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173 results on '"V. Sapunenko"'

1. Experience in dynamic tape drive allocation to manage scientific data

Author: A. Cavalli, D. Cesini, A. Falabella, E. Fattibene, F. Fornari, L. Morganti, A. Prosperini, and V. Sapunenko
Subjects: History, Computer Science Applications, Education
Abstract: The main computing and storage facility of INFN (Italian Institute for Nuclear Physics) running at CNAF hosts and manages tens of Petabytes of data produced by the LHC (Large Hadron Collider) experiments at CERN and other scientific collaborations in which INFN is involved. Most of these data are stored on tape resources of different technologies. All the tape drives can be used for administrative tasks (as repack, audit, space reclamation), as well to write and read data of all the experiments. Moreover, the usage of tape resources by scientific communities will become considerably more intense in the next years and the amount of data on tape will double by 2025. For these reasons, the issue of the concurrent access to tape drives is significant. We designed a software solution to optimize the efficiency of the shared usage of tape drives in our environment and put it in production in January 2020. In this paper we present the experience with such dynamic tape resources allocation in production. Comparing it with the previous static allocation method, we observed an improvement in reading throughput up to 85%. Moreover, we describe the new features added to our solution to optimize the efficiency of the shared usage of tape drives of different technologies.
Published: 2023

2. Distributed filesystems (GPFS, CephFS and Lustre-ZFS) deployment on Kubernetes/Docker clusters

Author: V. Sapunenko, Daniele Cesini, A Prosperini, Federico Fornari, A. Cavalli, Antonio Falabella, Enrico Fattibene, and Lucia Morganti
Subjects: Application programming interface, Exploit, Computer science, business.industry, Data management, computer.software_genre, Proof of concept, Server, Container (abstract data type), Operating system, Lustre (file system), Orchestration (computing), business, computer
Abstract: Nowadays Kubernetes has become a powerful tool to deploy and manage containerized applications. Modern datacenters need distributed filesystems to provide user applications with access to stored data on a large number of nodes. The possibility to mount a distributed filesystem and exploit its native application programming interfaces in a Docker container, combined with the advanced orchestration features provided by Kubernetes, may enhance flexibility in data management, installation, running and monitoring of transfer services. Moreover, it would allow the execution of dedicated services on different nodes, in isolated and automatically replicable environments, so to improve deployment efficiency and fail-safeness. The goal of this work is to demonstrate the feasibility of using Kubernetes and Docker to setup clients capable to access a distributed filesystem from existing clusters and to create clusters based on containerized servers. Despite being just a proof of concept, the effort has shown the possibility of using different types of distributed filesystems (GPFS, CephFS, Lustre-ZFS) with equally positive results.
Published: 2021

3. Recent evolutions in the LTDP CDF project

Author: Federico Fornari, Lucia Morganti, V. Sapunenko, Enrico Fattibene, Daniele Cesini, Antonio Falabella, A. Cavalli, and A Prosperini
Subjects: File system, Database, 010308 nuclear & particles physics, business.industry, Group method of data handling, Data management, Physics, QC1-999, computer.software_genre, 01 natural sciences, Sequential access, Metadata, Software, Virtual machine, 0103 physical sciences, Fermilab, 010306 general physics, business, computer
Abstract: In the latest years, CNAF (the national center of the Italian Institute for Nuclear Physics INFN dedicated to Research and Development on Information and Communication Technologies) has been working on the Long Term Data Preservation (LTDP) project for the CDF experiment, active at Fermilab from 1990 to 2011. The main aims of the project are to protect the most relevant part of the CDF RUN-2 data collected between 2001 and 2011 and already stored on tape at CNAF (4 PB), as well as to ensure the availability and the access to the analysis facility to those data over time. Lately, the CDF database, hosting information about CDF datasets such as their structure, file locations and metadata, has been imported from Fermilab to CNAF. Also, the Sequential Access via Metadata (SAM) station data handling tool for CDF data management, that allows to manage data transfers and to retrieve information from the CDF database, has been properly installed and configured at CNAF. This was a fundamental step in the perspective of a complete decommissioning of CDF services on Fermilab side. An access system has been designed and tested to submit CDF analysis jobs, using CDF software distributed via CERN Virtual Machine File System (CVMFS) and requesting delivery of CDF files stored on CNAF tapes, as well as data present only on Fermilab storage archive. Moreover, the availability and the correctness of all CDF data stored on CNAF tapes has been verified. This paper describes all these recent evolutions in detail, presenting the future plans for the LTDP project at CNAF.
Published: 2020

4. The ISO 27001 Certification

Author: C Vistoli, A Ferraro, B Martelli, A Chierici, D De Girolamo, E Giampieri, E Fattibene, G Maron, G Castellani, G Guizzunti, L Dell'agnello, M Donatelli, S Dal Pra, S Longo, S Zani, and V Sapunenko
Published: 2020
Full Text: View/download PDF

5. INDIGO-DataCloud -Filling the gaps

Author: C Aiftimiei, M Caberletti, A Ceccanti, S Dal Pra, E Fattibene, D Michelotto, E Ronchieri, D Salomoni, V Sapunenko, S Taneja, and S Zani
Published: 2020
Full Text: View/download PDF

6. AR to RUN3-2016

Author: L. Dell'Agnello, Cesini, Daniele, Pra, Stefano Dal, V. Sapunenko, Zani, Stefano, and Chierici, Andrea
Published: 2020
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7. HSM and backup services at INFN-CNAF

Author: A. Cavalli, Enrico Fattibene, V. Sapunenko, Daniele Cesini, and A Prosperini
Subjects: File system, Large Hadron Collider, 010308 nuclear & particles physics, business.industry, Data management, Physics, QC1-999, Petabyte, computer.software_genre, 01 natural sciences, Software, Backup, Server, 0103 physical sciences, Operating system, IBM, 010306 general physics, business, computer
Abstract: IBM Spectrum Protect (ISP) software, one of the leader solutions in data protection, contributes to the data management infrastructure operated at CNAF, the central computing and storage facility of INFN (Istituto Nazionale di Fisica Nucleare – Italian National Institute for Nuclear Physics). It is used to manage about 55 Petabytes of scientific data produced by LHC (Large Hadron Collider at CERN) and other experiments in which INFN is involved, stored on tape resources as the highest latency storage tier within HSM (Hierarchical Space Management) environment. To accomplish this task, ISP works together with IBM Spectrum Scale (formerly GPFS - General Parallel File System) and GEMSS (Grid Enabled Mass Storage System), an in-house developed software layer that manages migration and recall queues. Moreover, we perform backup/archive operation of main IT services running at CNAF, such as mail servers, configurations, repositories, documents, logs, etc. In this paper we present the current configuration of the HSM infrastructure and the backup and recovery service, with particular attention to issues related to the increasing amount of scientific data to manage, expected for the next years.
Published: 2019

8. A Comparison of Data-Access Platforms for the Computing of Large Hadron Collider Experiments

Author: M. Bencivenni, A. Chierici, A. D’Apice, D. De Girolamo, L. dell’Agnello, M. Donatelli, G. Donvito, A. Fella, A. Forti, F. Furano, A. Ghiselli, A. Italiano, E. Lanciotti, G. Lo Re, L. Magnoni, U. Marconi, B. Martelli, M. Mazzucato, P. P. Ricci, F. Rosso, D. Salomoni, R. Santinelli, V. Sapunenko, R. Veraldi, D. Vitlacil, S. Zani, R. Zappi, CARBONE, ANGELO, GALLI, DOMENICO, VAGNONI, VINCENZO MARIA, M. Bencivenni, A. Carbone, A. Chierici, A. D’Apice, D. De Girolamo, L. dell’Agnello, M. Donatelli, G. Donvito, A. Fella, A. Forti, F. Furano, D. Galli, A. Ghiselli, A. Italiano, E. Lanciotti, G. Lo Re, L. Magnoni, U. Marconi, B. Martelli, M. Mazzucato, P. P. Ricci, F. Rosso, D. Salomoni, R. Santinelli, V. Sapunenko, V. Vagnoni, R. Veraldi, D. Vitlacil, S. Zani, and R. Zappi
Subjects: Nuclear and High Energy Physics, Large Hadron Collider, COMPUTER FACILITIES, business.industry, Computer science, SYSTEM ANALYSIS AND DESIGN, computer.software_genre, MASS MEMORY, Storage area network, Fibre Channel, HIGH ENERGY PHYSICS, Data access, Nuclear Energy and Engineering, Grid computing, Gigabit, Scalability, Operating system, DATA HANDLING, Data center, LHC, Electrical and Electronic Engineering, business, computer
Abstract: Performance, reliability and scalability in data-access are key issues in the context of the computing Grid and High Energy Physics data processing and analysis applications, in particular considering the large data size and I/O load that a Large Hadron Collider data centre has to support. In this paper we present the technical details and the results of a large scale validation and performance measurement employing different data-access platforms—namely CASTOR, dCache, GPFS and Scalla/Xrootd. The tests have been performed at the CNAF Tier-1, the central computing facility of the Italian National Institute for Nuclear Research (INFN). Our storage back-end was based on Fibre Channel disk-servers organized in a Storage Area Network, being the disk-servers connected to the computing farm via Gigabit LAN. We used 24 disk-servers, 260 TB of raw-disk space and 280 worker nodes as computing clients, able to run concurrently up to about 1100 jobs. The aim of the test was to perform sequential and random read/write accesses to the data, as well as more realistic access patterns, in order to evaluate efficiency, availability, robustness and performance of the various data-access solutions.
Published: 2008

9. INFN Tier–1: a distributed site

Author: Gaetano Maron, Antonio Falabella, A Prosperini, L Chiarelli, V. Sapunenko, Lucia Morganti, Tommaso Boccali, Andrea Chierici, Enrico Fattibene, S Zani, Donato De Girolamo, L. dell'Agnello, Diego Michelotto, Daniele Cesini, and Stefano Dal Pra
Subjects: Large Hadron Collider, 010308 nuclear & particles physics, Physics, QC1-999, 0103 physical sciences, Operating system, High bandwidth, 010306 general physics, computer.software_genre, 01 natural sciences, computer, Tier 1 network
Abstract: The INFN Tier-1 center at CNAF has been extended in 2016 and 2017 in order to include a small amount of resources (∼ 22 kHS06 corresponding to ∼ 10% of the CNAF pledges for LHC in 2017) physically located at the Bari-ReCas site (∼ 600 km distant from CNAF). In 2018, a significant fraction of the CPU power (∼ 170 kHS06, equivalent to ∼ 50% of the total CNAF pledges) is going to be provided via a collaboration with the PRACE Tier-0 CINECA center (a few km from CNAF), thus building a truly geographically distributed (WAN) center. The two sites are going to be interconnected via an high bandwidth link (400-1200 Gb/s), in order to ensure a transparent access to data residing on CNAF storage; the latency between the centers is small enough not to require particular caching strategies. In this contribution we describe the issues and the results of the production configuration, focusing both on the management aspects and on the performance provided to end-users.
Published: 2019

10. Elastic Extension of a CMS Computing Centre Resources on External Clouds

Author: V. Sapunenko, Giovanni Zizzi, Diego Michelotto, G. Codispoti, D. DeGirolamo, M. Panella, G. Peco, Daniele Bonacorsi, S Dal Pra, Alessandro Costantini, V. Ciaschini, Massimo Sgaravatto, C. Grandi, R. Di Maria, C. Aiftimiei, Sonia Taneja, and P. Calligola
Subjects: History, Focus (computing), Engineering, Large Hadron Collider, business.industry, Distributed computing, 02 engineering and technology, Extension (predicate logic), 021001 nanoscience & nanotechnology, Grid, 01 natural sciences, Computer Science Applications, Education, Computing and Computers, World Wide Web, Work (electrical), Proof of concept, Order (exchange), 0103 physical sciences, Use case, 010306 general physics, 0210 nano-technology, business
Abstract: After the successful LHC data taking in Run-I and in view of the future runs, the LHC experiments are facing new challenges in the design and operation of the computing facilities. The computing infrastructure for Run-II is dimensioned to cope at most with the average amount of data recorded. The usage peaks, as already observed in Run-I, may however originate large backlogs, thus delaying the completion of the data reconstruction and ultimately the data availability for physics analysis. In order to cope with the production peaks, CMS - along the lines followed by other LHC experiments - is exploring the opportunity to access Cloud resources provided by external partners or commercial providers. Specific use cases have already been explored and successfully exploited during Long Shutdown 1 (LS1) and the first part of Run 2. In this work we present the proof of concept of the elastic extension of a CMS site, specifically the Bologna Tier-3, on an external OpenStack infrastructure. We focus on the "Cloud Bursting" of a CMS Grid site using a newly designed LSF configuration that allows the dynamic registration of new worker nodes to LSF. In this approach, the dynamically added worker nodes instantiated on the OpenStack infrastructure are transparently accessed by the LHC Grid tools and at the same time they serve as an extension of the farm for the local usage. The amount of resources allocated thus can be elastically modeled to cope up with the needs of CMS experiment and local users. Moreover, a direct access/integration of OpenStack resources to the CMS workload management system is explored. In this paper we present this approach, we report on the performances of the on-demand allocated resources, and we discuss the lessons learned and the next steps.
Published: 2016

11. Dynamic sharing of tape drives accessing scientific data

Author: V. Sapunenko, Daniele Cesini, A Prosperini, Enrico Fattibene, A. Cavalli, Lucia Morganti, and P. P. Ricci
Subjects: History, Computer science, Computer Science Applications, Education
Published: 2018

12. Moments of the spin structure functions g1p and g1d for 0.05<Q2<3.0 GeV2

Author: R. A. Schumacher, G. V. O'Rielly, C. D. Keith, Cynthia Marie Hadjidakis, Z. W. Zhao, Chaden Djalali, D. G. Jenkins, Michael Dugger, S. Tkachenko, H. O. Funsten, A. I. Ostrovidov, A. C S Lima, S. Bültmann, L. Morand, M. R. Niroula, T. A. Forest, D. G. Ireland, G. Asryan, Volker D. Burkert, A. S. Biselli, J. Pierce, Elton Smith, M. J. Amaryan, M. MacCormick, O. P. Dzyubak, R. A. Niyazov, I. Hleiqawi, S. L. Careccia, Larry Weinstein, Avraham Klein, E. Golovatch, H. G. Juengst, K. Moriya, Daniel S. Carman, J. Kuhn, Philip L. Cole, S. McAleer, H. Hakobyan, S. Anefalos Pereira, P. D. Rubin, L. Blaszczyk, P. Corvisiero, Y. G. Sharabian, A. Fradi, L. Cheng, G. Audit, A.V. Stavinsky, C. E. Hyde-Wright, F. Sabatié, Nikolay Shvedunov, D. Heddle, P. Stoler, Friedrich Klein, J. P. Cummings, R. De Vita, N. Markov, V. Sapunenko, C. Salgado, Dinko Pocanic, L. Elouadrhiri, N. Kalantarians, S. Stepanyan, K. S. Egiyan, R. C. Minehart, C. A. Meyer, J. Ball, M. Taiuti, S. E. Kuhn, I. I. Strakovsky, M. Bektasoglu, M. Kossov, K. Mikhailov, K.H. Hicks, R. J. Feuerbach, G. V. Fedotov, M. Nozar, A. Deur, I. Popa, V. Crede, J. W. Price, Shifeng Chen, M. Anghinolfi, Laird Kramer, D. P. Watts, H. Egiyan, G. Gavalian, John A. Mueller, L. Casey, B. L. Berman, P. Mattione, B. B. Niczyporuk, G. Rosner, N. Benmouna, N. Pivnyuk, Kwangsoo Kim, J. T. Goetz, M. Mirazita, G. Riccardi, J. R. Calarco, R. A. Miskimen, B. A. Raue, B. McKinnon, W. J. Briscoe, L. M. Qin, R. G. Fersh, P. Eugenio, J. Langheinrich, C. Butuceanu, C. Hanretty, S. S. Stepanyan, E. Pasyuk, S. A. Philips, M. Ripani, G. Ricco, S. A. Morrow, C. Paterson, Y. Ilieva, Michael Vineyard, Victor Mokeev, M. Klusman, B. M. Preedom, D. Branford, P. Collins, B. Moreno, J. R. Johnstone, Lorenzo Zana, J. P. Santoro, Tsutomu Mibe, Gerald Feldman, J. M. Laget, L. Todor, D. Protopopescu, K. L. Giovanetti, S. V. Kuleshov, C. Marchand, S. Pozdniakov, M. Garçon, M. L. Seely, Ji Li, D. J. Tedeschi, G. E. Dodge, H. Y. Lu, J. Lachniet, I. Bedlinskiy, Marco A. Huertas, A. Tkabladze, M. D. Mestayer, E. L. Isupov, P. V. Degtyarenko, D. Rowntree, K. Livingston, Michael L. Williams, M. Holtrop, R. Suleiman, V. Kuznetsov, D. S. Dale, J. Zhang, S. Boiarinov, D. I. Sober, Gerard Gilfoyle, F. X. Girod, G. S. Mutchler, N. A. Baltzell, I. Niculescu, D. Sokhan, J. Salamanca, K. A. Griffioen, D. Lawrence, M. Guillo, N. Guler, R. De Masi, L. El Fassi, J. W C McNabb, Sylvain Bouchigny, H. Denizli, M. Guidal, M. Battaglieri, J. Hardie, S. Strauch, J. D. Kellie, Z. Krahn, R. Nasseripour, S. Barrow, P. Rossi, R. Dickson, N. Baillie, D. Doughty, V. Gyurjyan, R. Bradford, K. Lukashin, B. E. Stokes, G. S. Adams, H. Bagdasaryan, P. Nadel-Turonski, A. V. Skabelin, K. Joo, A. Cazes, S. Procureur, Maryam Moteabbed, Bernhard Mecking, K. V. Dharmawardane, L. Guo, M. Ungaro, D. P. Weygand, E. Wolin, N. Hassall, M. Bellis, D. G. Crabb, J. Yun, D. Cords, P. Bosted, A. Yegneswaran, N. Dashyan, Y. Prok, Barry Ritchie, E. De Sanctis, H. S. Jo, S. Niccolai, R. Fatemi, A. V. Vlassov, P. Coltharp, R. W. Gothe, M. M. Ito, K. Y. Kim, M. Osipenko, K. Beard, L. C. Smith, E. Munevar, Kalvir S. Dhuga, B. S. Ishkhanov, O. Pogorelko, M. Khandaker, B. Zhao, F. W. Hersman, W. Kim, G. Niculescu, N. Gevorgyan, L. C. Dennis, B. E. Bonner, H. Avakian, D. Sharov, S. A. Dytman, W. K. Brooks, K. Park, V. P. Kubarovsky, J. Shaw, Michael Wood, K. Hafidi, and V. S. Serov
Subjects: Physics, Nuclear and High Energy Physics, Chiral perturbation theory, Heavy baryon chiral perturbation theory, Proton, 010308 nuclear & particles physics, Nuclear Theory, Hadron, 01 natural sciences, Baryon, Nuclear physics, Polarizability, 0103 physical sciences, Sum rule in quantum mechanics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: The spin structure functions g 1 for the proton and the deuteron have been measured over a wide kinematic range in x and Q 2 using 1.6 and 5.7 GeV longitudinally polarized electrons incident upon polarized NH3 and ND3 targets at Jefferson Lab. Scattered electrons were detected in the CEBAF Large Acceptance Spectrometer, for 0.05 Q 2 5 GeV 2 and W 3 GeV . The first moments of g 1 for the proton and deuteron are presented – both have a negative slope at low Q 2 , as predicted by the extended Gerasimov–Drell–Hearn sum rule. The first extraction of the generalized forward spin polarizability of the proton γ 0 p is also reported. This quantity shows strong Q 2 dependence at low Q 2 . Our analysis of the Q 2 evolution of the first moment of g 1 shows agreement in leading order with Heavy Baryon Chiral Perturbation Theory. However, a significant discrepancy is observed between the γ 0 p data and Chiral Perturbation calculations for γ 0 p , even at the lowest Q 2 .
Published: 2009

13. Exclusive ρ0 electroproduction on the proton at CLAS

Author: J. Langheinrich, S. S. Stepanyan, E. Pasyuk, S. A. Philips, N. Dashyan, V. Sapunenko, G. Ricco, Alexei V. Klimenko, N. A. Baltzell, C. Salgado, Dinko Pocanic, Barry Ritchie, H. Denizli, A. V. Skabelin, K. A. Griffioen, B. Zhao, V. Gyurjyan, A. I. Ostrovidov, R. Fatemi, K. Park, S. E. Kuhn, Latifa Elouadrhiri, R. C. Minehart, Kei Moriya, C. A. Meyer, H. G. Juengst, B. E. Stokes, G. S. Adams, G. V. Fedotov, V. P. Kubarovsky, J. Zhang, P. Eugenio, K. P. Adhikari, A. V. Vlassov, D. P. Weygand, G. E. Dodge, H. Y. Lu, M. J. Amaryan, G. V. O'Rielly, S. Niccolai, Z. W. Zhao, V. Mokeev, Y. Ilieva, Ji Li, D. G. Jenkins, C. Tur, Gerard Gilfoyle, Elton Smith, H. Hakobyan, A.V. Stavinsky, J. D. Kellie, M. Guidal, M. MacCormick, I. Hleiqawi, S. L. Careccia, R. De Vita, Friedrich Klein, Brian Raue, P. V. Degtyarenko, M. D. Mestayer, J. P. Didelez, R. Nasseripour, L. Todor, F. W. Hersman, P. Coltharp, E. L. Isupov, J. P. Cummings, W. Gohn, S. A. Morrow, S. McAleer, M. Anghinolfi, P. Nadel-Turonski, D. Sokhan, D. Protopopescu, D. J. Tedeschi, M. Holtrop, Michael L. Williams, P. Collins, K. L. Giovanetti, I. Niculescu, F. X. Girod, L. Blaszczyk, B. Carnahan, James Mueller, D. Lawrence, R. G. Fersch, R. A. Miskimen, B. McKinnon, S. Pozdniakov, M. Garçon, J. J. Melone, M. M. Ito, S. Boiarinov, Larry Weinstein, L. Zana, P. D. Rubin, R. De Masi, D. Keller, I. Bedlinskiy, B. M. Preedom, S. Anefalos Pereira, D. Schott, Y. G. Sharabian, R. A. Schumacher, P. L. Cole, M. Yurov, M. Taiuti, S. Mehrabyan, D. Branford, L. C. Smith, E. Munevar, G. S. Mutchler, B. S. Ishkhanov, Michael Wood, K. Hafidi, L. Graham, M. Kossov, M. E. McCracken, C. I O Gordon, J. M. Laget, V. Kuznetsov, J. Kuhn, E. Hourany, M. Khandaker, V. S. Serov, L. C. Dennis, B. E. Bonner, J. W. Price, Tsutomu Mibe, S. Bültmann, G. Audit, Shifeng Chen, C. Bookwalter, N. Gevorgyan, M. Osipenko, C. E. Hyde-Wright, J. P. Santoro, H. S. Jo, H. Avakian, L. Morand, I. Popa, D. Sharov, T. A. Forest, G. Riccardi, M. R. Niroula, E. De Sanctis, O. Pogorelko, S. Stepanyan, P. Mattione, C. Butuceanu, M. S. Saini, D. Doughty, J. Pierce, M. Ripani, B. L. Berman, Avraham Klein, L. M. Qin, M. Aghasyan, E. Wolin, Sergey Kuleshov, W. J. Briscoe, D. Heddle, J. T. Goetz, D. I. Sober, Kalvir S. Dhuga, M. Bektasoglu, S. A. Dytman, S. Dhamija, M. Nozar, E. Polli, M. Mirazita, C. Paterson, J. P. Ball, R. W. Gothe, Y. Prok, B. Moreno, W. Kim, J. Hardie, Hall Crannell, D. S. Carman, K. Livingston, G. Rosner, C. Marchand, G. Niculescu, D. S. Dale, N. Baillie, S. Park, Sylvain Bouchigny, J. Lachniet, A. Tkabladze, D. G. Crabb, R. Dickson, Michael Vineyard, D. G. Ireland, V. Crede, J. R. Calarco, P. Khetarpal, N. Guler, J. Salamanca, L. El Fassi, J. W C McNabb, S. Barrow, P. Rossi, L. Casey, H. Bagdasaryan, Volker D. Burkert, A. S. Biselli, B. B. Niczyporuk, N. Pivnyuk, P. Stoler, C. Hanretty, Laird Kramer, J. R. Johnstone, L. Guo, M. Ungaro, A. Fradi, K. Joo, D. Cords, N. Markov, A. Yegneswaran, K. Hicks, M. Battaglieri, R. Bradford, K. S. Egiyan, A. Cazes, S. Procureur, Maryam Moteabbed, Bernhard Mecking, K. V. Dharmawardane, N. Hassall, M. Bellis, K. Mikhailov, G. Asryan, O. P. Dzyubak, R. A. Niyazov, P. Corvisiero, S. Strauch, D. P. Watts, H. Egiyan, I. I. Strakovsky, A. Deur, W. K. Brooks, R. J. Feuerbach, Cynthia Marie Hadjidakis, M. Guillo, Chaden Djalali, Michael Dugger, L. Cheng, F. Sabatié, Nikolay Shvedunov, N. Kalantarians, G. Gavalian, S. Tkachenko, and N. Benmouna
Subjects: Quark, Physics, REPRESENTATION, Nuclear and High Energy Physics, Particle physics, Valence (chemistry), Proton, Hadron, Parton, VECTOR-MESON ELECTROPRODUCTION, Approx, PHOTONS, QCD, EVOLUTION, High Energy Physics - Experiment, Regge theory, Nuclear physics, Scattering amplitude, GENERALIZED PARTON DISTRIBUTIONS, VIRTUAL COMPTON-SCATTERING, VECTOR-MESON ELECTROPRODUCTION, LARGE MOMENTUM-TRANSFER, DIFFRACTIVE PRODUCTION, PHOTOPRODUCTION, PHOTONS, QCD, REPRESENTATION, EVOLUTION, LARGE MOMENTUM-TRANSFER, GENERALIZED PARTON DISTRIBUTIONS, DIFFRACTIVE PRODUCTION, PHOTOPRODUCTION, Nuclear Experiment, VIRTUAL COMPTON-SCATTERING
Abstract: The $e p\to e^\prime p \rho^0$ reaction has been measured, using the 5.754 GeV electron beam of Jefferson Lab and the CLAS detector. This represents the largest ever set of data for this reaction in the valence region. Integrated and differential cross sections are presented. The $W$, $Q^2$ and $t$ dependences of the cross section are compared to theoretical calculations based on $t$-channel meson-exchange Regge theory on the one hand and on quark handbag diagrams related to Generalized Parton Distributions (GPDs) on the other hand. The Regge approach can describe at the $\approx$ 30% level most of the features of the present data while the two GPD calculations that are presented in this article which succesfully reproduce the high energy data strongly underestimate the present data. The question is then raised whether this discrepancy originates from an incomplete or inexact way of modelling the GPDs or the associated hard scattering amplitude or whether the GPD formalism is simply inapplicable in this region due to higher-twists contributions, incalculable at present., Comment: 29 pages, 29 figures
Published: 2008

14. Measurement of the x- and Q2-dependence of the asymmetry A1 on the nucleon

Author: L. Elouadrhiri, R. A. Miskimen, M. Khandaker, B. McKinnon, G. Rosner, I. I. Strakovsky, R. W. Gothe, M. Bellis, D. Branford, P. Rossi, K. Y. Kim, A. Deur, S. V. Kuleshov, H. G. Juengst, K. S. Egiyan, P. V. Degtyarenko, P. Dragovitsch, M. Battaglieri, M. Nozar, D. J. Tedeschi, M. Taiuti, I. Bedlinskiy, L. Todor, J. P. Cummings, D. Doughty, F. X. Girod, S. Niccolai, D. Protopopescu, Laird Kramer, J. Hardie, V. Gyurjyan, R. De Masi, B. E. Stokes, F. Ronchetti, R. A. Schumacher, P. Corvisiero, V. P. Kubarovsky, G. S. Adams, D. Heddle, Brian Raue, M. Mirazita, G. Ricco, Dinko Pocanic, L. C. Smith, S. Tkachenko, R. Bradford, K. Lukashin, Y. G. Sharabian, O. Pogorelko, E. Wolin, S. McAleer, S. E. Kuhn, V. Sapunenko, B. S. Ishkhanov, Ji Li, Jean Laget, N. Benmouna, N. Pivnyuk, Rakhsha Nasseripour, B. Carnahan, L. C. Dennis, B. E. Bonner, M. Guillo, C. Tur, J. Napolitano, A. I. Ostrovidov, R. Fatemi, A. C S Lima, Gerard Gilfoyle, D. Cords, Marco A. Huertas, H. Avakian, E. S. Smith, K. Park, A. V. Vlassov, D. G. Ireland, M. R. Niroula, V. Batourine, B. Zhao, Y. Ilieva, E. L. Isupov, R. Suleiman, I. Hleiqawi, L. Guo, S. Bültmann, Volker D. Burkert, A. S. Biselli, H. S. Jo, E. Golovatch, Michael L. Williams, P. Bosted, S. L. Careccia, James Mueller, G. S. Mutchler, R. DeVita, M. Ripani, S. A. Morrow, Atilla Gonenc, M. MacCormick, C. Djalali, F. W. Hersman, T. A. Forest, M. Anghinolfi, P. D. Rubin, S. Stepanyan, A. Cazes, G. Gavalian, J. W. Price, S. Boiarinov, Maryam Moteabbed, B. M. Preedom, N. A. Baltzell, Sylvain Bouchigny, J. P. Ball, Y. Prok, K. L. Giovanetti, Michael Dugger, A. Yegneswaran, Shifeng Chen, K. V. Dharmawardane, J. Pierce, M. Kossov, Avraham Klein, Jens H. Kuhn, A. Stavinsky, Larry Weinstein, P. Ambrozewicz, E. Pasyuk, L. M. Qin, K. A. Griffioen, H. O. Funsten, P. Coltharp, U. Thoma, C. Keith, Lorenzo Zana, D. P. Weygand, S. A. Dytman, Hall Crannell, M. M. Ito, N. Baillie, J. T. Goetz, G. V. O'Rielly, C. Paterson, M. Klusman, K. Livingston, V. Crede, Z. W. Zhao, Frank Klein, D. G. Crabb, J. R. Calarco, S. Strauch, D. G. Jenkins, C. Salgado, J. D. Kellie, G. E. Dodge, S. Pozdniakov, N. Guler, J. W C McNabb, M. D. Mestayer, I. Niculescu, Nikolay Shvedunov, D. Lawrence, M. Guidal, D. I. Sober, S. S. Stepanyan, M. Osipenko, S. Barrow, F. Sabatié, Michael Vineyard, K. Beard, M. Garçon, B. Mecking, G. Riccardi, J. Shaw, C. Butuceanu, Michael Wood, W. K. Brooks, K. Hafidi, V. S. Serov, Victor Mokeev, M. Ungaro, K. Joo, J. Yun, J. P. Santoro, Roy Thompson, K. Kim, J. J. Manak, P. Eugenio, J. Zhang, H. Bagdasaryan, P. Collins, Daniel S. Carman, C. Hadjidakis, C. E. Hyde-Wright, M. Bektasoglu, J. Langheinrich, S. A. Philips, G. Niculescu, M. Holtrop, Hong Lu, P. L. Cole, P. Nadel-Turonski, Tsutomu Mibe, B. B. Niczyporuk, J. Lachniet, A. Tkabladze, D. Rowntree, R. S. Hakobyan, J. Donnelly, O. P. Dzyubak, R. A. Niyazov, R. J. Feuerbach, L. Morand, P. Stoler, E. De Sanctis, K. Hicks, W. Kim, Susan Taylor, K. Mikhailov, H. Egiyan, N. Markov, Barry Ritchie, G. Asryan, H. Denizli, A. V. Skabelin, R. C. Minehart, C. A. Meyer, G. V. Fedotov, and E. Polli
Subjects: Quark, Physics, Nuclear and High Energy Physics, Particle physics, Proton, 010308 nuclear & particles physics, media_common.quotation_subject, Momentum transfer, Quark model, Parton, 01 natural sciences, Asymmetry, Nuclear physics, 0103 physical sciences, Invariant mass, 010306 general physics, Nucleon, media_common
Abstract: We report results for the virtual photon asymmetry A{sub 1} on the nucleon from new Jefferson Lab measurements. The experiment, which used the CEBAF Large Acceptance Spectrometer and longitudinally polarized proton ({sup 15}NH{sub 3}) and deuteron ({sup 15}ND{sub 3}) targets, collected data with a longitudinally polarized electron beam at energies between 1.6 GeV and 5.7 GeV. In the present paper, we concentrate on our results for A{sub 1}(x,Q{sup 2}) and the related ratio g{sub 1}/F{sub 1}(x,Q{sup 2}) in the resonance and the deep inelastic regions for our lowest and highest beam energies, covering a range in momentum transfer Q{sup 2} from 0.05 to 5.0 GeV{sup 2} and in final-state invariant mass W up to about 3 GeV. Our data show detailed structure in the resonance region, which leads to a strong Q{sup 2}--dependence of A{sub 1}(x,Q{sup 2}) for W below 2 GeV. At higher W, a smooth approach to the scaling limit, established by earlier experiments, can be seen, but A{sub 1}(x,Q{sup 2}) is not strictly Q{sup 2}--independent. We add significantly to the world data set at high x, up to x = 0.6. Our data exceed the SU(6)-symmetric quark model expectation for both the proton and the deuteron whilemore » being consistent with a negative d-quark polarization up to our highest x. This data set should improve next-to-leading order (NLO) pQCD fits of the parton polarization distributions.« less
Published: 2006

15. Performance of 10 Gigabit Ethernet Using Commodity Hardware

Author: L. dell'Agnello, D Gregori, V. Sapunenko, V. Vagnoni, M. Onofri, Stefano Perazzini, B Martelli, Marco Bencivenni, Andrea Chierici, M. Donatelli, Donato De Girolamo, D. Galli, S Zani, Davide Salomoni, Umberto Marini Bettolo Marconi, A. Italiano, Elisabetta Ronchieri, A Prosperini, Armando Fella, A. Carbone, Antonia Ghiselli, Maria Cristina Vistoli, R. Veraldi, F Rosso, A. Cavalli, G. Peco, M. Mazzucato, Rajeev Kumar, D. Bortolotti, P. P. Ricci, Stefano Dal Pra, M. Bencivenni, D. Bortolotti, A. Carbone, A. Cavalli, A. Chierici, S. Dal Prà, D. De Girolamo, L. dell'Agnello, M. Donatelli, A. Fella, D. Galli, A. Ghiselli, D. Gregori, A. Italiano, R. Kumar, U. Marconi, B. Martelli, M. Mazzucato, M. Onofri, G. Peco, S. Perazzini, A. Prosperini, P. P. Ricci, E. Ronchieri, F. Rosso, D. Salomoni, V. Sapunenko, V. Vagnoni, R. Veraldi, M. C. Vistoli, and S. Zani.
Subjects: Nuclear and High Energy Physics, Computer science, business.industry, COMPUTER NETWORK PERFORMANCE, NETWORK INTERFACES, ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS, 10 Gigabit Ethernet, Jumbo frame, Metro Ethernet, LHCb, TCP offload engine, Synchronous Ethernet, LOCAL AREA NETWORKS, Nuclear Energy and Engineering, Network interface controller, DATA ACQUISITION, TRIGGERING, LHC, Electrical and Electronic Engineering, ATA over Ethernet, business, Computer network, Carrier Ethernet
Abstract: In the prospect of employing 10 Gigabit Ethernet as networking technology for online systems and offline data analysis centers of High Energy Physics experiments, we performed a series of measurements on the performance of 10 Gigabit Ethernet, using the network interface cards mounted on the PCI-Express bus of commodity PCs both as transmitters and receivers. In real operating conditions, the achievable maximum transfer rate through a network link is not only limited by the capacity of the link itself, but also by that of the memory and peripheral buses and by the ability of the CPUs and of the Operating System to handle packet processing and interrupts raised by the network interface cards in due time. Besides the TCP and UDP maximum data transfer throughputs, we also measured the CPU loads of the sender/receiver processes and of the interrupt and soft-interrupt handlers as a function of the packet size, either using standard or ``jumbo'' Ethernet frames. In addition, we also performed the same measurements by simultaneously reading data from Fibre Channel links and forwarding them through a 10 Gigabit Ethernet link, hence emulating the behavior of a disk server in a Storage Area Network exporting data to client machines via 10 Gigabit Ethernet.
Published: 2010

16. Extending the farm on external sites: the INFN Tier-1 experience

Author: S Virgilio, V. Sapunenko, A. Falabella, L Chiarelli, Andrea Chierici, Enrico Fattibene, Tommaso Boccali, S Zani, A Prosperini, Gaetano Maron, D De Girolamo, S. Dal Pra, L. dell'Agnello, Daniele Cesini, A. Cavalli, and V. Ciaschini
Subjects: History, Large Hadron Collider, Computer science, business.industry, Cloud computing, Computer Science Applications, Education, Tier 1 network, Upgrade, General purpose, High bandwidth, Data center, Latency (engineering), business, Telecommunications, Simulation
Abstract: The Tier-1 at CNAF is the main INFN computing facility offering computing and storage resources to more than 30 different scientific collaborations including the 4 experiments at the LHC. It is also foreseen a huge increase in computing needs in the following years mainly driven by the experiments at the LHC (especially starting with the run 3 from 2021) but also by other upcoming experiments such as CTA[1] While we are considering the upgrade of the infrastructure of our data center, we are also evaluating the possibility of using CPU resources available in other data centres or even leased from commercial cloud providers. Hence, at INFN Tier-1, besides participating to the EU project HNSciCloud, we have also pledged a small amount of computing resources (~ 2000 cores) located at the Bari ReCaS[2] for the WLCG experiments for 2016 and we are testing the use of resources provided by a commercial cloud provider. While the Bari ReCaS data center is directly connected to the GARR network[3] with the obvious advantage of a low latency and high bandwidth connection, in the case of the commercial provider we rely only on the General Purpose Network. In this paper we describe the set-up phase and the first results of these installations started in the last quarter of 2015, focusing on the issues that we have had to cope with and discussing the measured results in terms of efficiency.
Published: 2017

17. The CLAS Electromagnetic Calorimeter at Large Angles

Author: Paolo Rossi, H. Avakian, Marco Ripani, V. Sapunenko, Victor Mokeev, R. De Vita, P. Corvisiero, M. Battaglieri, E. Polli, M. Mirazita, M. Taiuti, F. Ronchetti, V. Muccifora, V. Gyuriyan, M. Anghinolfi, N. Bianchi, M. Osipenko, E. Golovach, and Giovanni Ricco
Subjects: Physics, Nuclear and High Energy Physics, Spectrometer, Physics::Instrumentation and Detectors, Monte Carlo method, Detector, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Scintillator, Calorimeter, Nuclear physics, Electromagnetic calorimeter, Calibration, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Instrumentation, Nuclear Experiment, Energy (signal processing)
Abstract: The study of the response of the two modules of the large-angle electromagnetic shower calorimeter (LAC) of the CLAS detector to charged and neutral particles is reported. The results agree very well with the Monte Carlo simulation. The procedures adopted for the energy and timing calibration are also discussed, proving that the module geometry allows for simple self-calibrating energy and timing algorithms.
Published: 2014

18. Phenomenological model for describing pion-pair production on a proton by virtual photons in the energy region of nucleon-resonance excitation

Author: M. Anginolfi, M. Ripani, B. S. Ishkhanov, G. Ricco, E. N. Golovach, M. Taiuti, V. V. Sapunenko, M. Battaglieri, M. Osipenko, G. V. Fedotov, and Victor Mokeev
Subjects: Physics, Nuclear and High Energy Physics, Proton, Nuclear Theory, Virtual particle, Atomic and Molecular Physics, and Optics, Nuclear physics, Cross section (physics), Pion, Pair production, Phenomenological model, Nuclear Experiment, Nucleon, Energy (signal processing)
Abstract: A phenomenological model is developed for describing the production of π + π − pairs on a proton by virtual photons in the energy region of nucleon-resonance excitation.The cross sections are calculated for the channels γp → π −Δ++, γp → π +Δ0, and γp → ρp, which make a dominant contribution to pion-pair production, and the results are compared with available experimental data.The contributions of nucleon resonances to the cross section for the reaction γp → π −Δ++ are predicted within the developed approach.
Published: 2001

19. LHCb experience with LFC replication

Author: G L Re, G. Peco, V. Vagnoni, A. Carbone, A D'Apice, M Girone, E D Perez, V. Sapunenko, P. P. Ricci, D Duellmann, D Vitlacil, B Martelli, L. dell'Agnello, F. Bonifazi, F Bonifazi, A Carbone, E D Perez, A D'Apice, L dell'Agnello, D Duellmann, M Girone, G L Re, B Martelli, G Peco, P P Ricci, V Sapunenko, V Vagnoni, and D Vitlacil
Subjects: History, Distributed Computing Environment, GRID COMPUTING, Large Hadron Collider, LFC, DATABASE, Computer science, business.industry, Data management, LHCB EXPERIMENT, computer.software_genre, Grid, Replication (computing), Oracle, Computer Science Applications, Education, Computing and Computers, Grid computing, Scalability, Operating system, business, computer
Abstract: Database replication is a key topic in the framework of the LHC Computing Grid to allow processing of data in a distributed environment. In particular, the LHCb computing model relies on the LHC File Catalog, i.e. a database which stores information about files spread across the GRID, their logical names and the physical locations of all the replicas. The LHCb computing model requires the LFC to be replicated at Tier-1s. The LCG 3D project deals with the database replication issue and provides a replication service based on Oracle Streams technology. This paper describes the deployment of the LHC File Catalog replication to the INFN National Center for Telematics and Informatics (CNAF) and to other LHCb Tier-1 sites. We performed stress tests designed to evaluate any delay in the propagation of the streams and the scalability of the system. The tests show the robustness of the replica implementation with performance going much beyond the LHCb requirements.
Published: 2007

20. Performance Studies of the StoRM Storage Resource ManagerThird IEEE International Conference on e-Science and Grid Computing (e-Science 2007)

Author: CARBONE, ANGELO, L. dell'Agnello, A. Forti, A. Ghiselli, E. Lanciotti, L. Magnoni, M. Mazzucato, R. Santinelli, V. Sapunenko, V. Vagnoni, R. Zappi, A. Carbone, L. dell'Agnello, A. Forti, A. Ghiselli, E. Lanciotti, L. Magnoni, M. Mazzucato, R. Santinelli, V. Sapunenko, V. Vagnoni, and R. Zappi
Subjects: GRID COMPUTING, DISTRIBUTED COMPUTING
Published: 2007

21. Measurement of high lying nucleon resonances and search for a missing state in double charged pion electroproduction off the proton

Author: Giovanni Ricco, V. Sapunenko, M. Osipenko, Nikolay Shvedunov, A. A. Boluchevskii, Marco Ripani, G. V. Fedotov, B. S. Ishkhanov, V. Mokeev, M. Anghinolfi, R. De Vita, E. N. Golovach, M. Battaglieri, M. Taiuti, and Volker D. Burkert
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Meson, Proton, Nuclear Theory, Hadron, Resonance, Elementary particle, Atomic and Molecular Physics, and Optics, Baryon, Nuclear physics, Pion, High Energy Physics::Experiment, Nuclear Experiment, Nucleon
Abstract: We have analyzed data taken by the CLAS collaboration in double charged pion electroproduction off the proton. We have used an isobar model specifically developed for the analysis of the Nππ channel. This approach relates baryon resonance parameters to the experimental cross section, allowing the extraction of electromagnetic and some strong couplings from the fit to the data. A remarkable feature of the CLAS data is a resonance structure around 1.7 GeV which has not been seen in double pion photoproduction. The structure appears at all Q 2 values from 0.5 to 1.5 GeV 2 and it can not be reproduced with conventional N ∗ parameters.
Published: 2003

22. An integrated solution for remote data access

Author: Domenico D'Urso, V. Sapunenko, V. Vagnoni, L. dell'Agnello, and Matteo Duranti
Subjects: File system, History, business.industry, Atomic force microscopy, Computer science, Data management, computer.software_genre, Computer Science Applications, Education, Data access, Operating system, Data center, Namespace, IBM, business, Disk space, computer
Abstract: Data management constitutes one of the major challenges that a geographically- distributed e-Infrastructure has to face, especially when remote data access is involved. We discuss an integrated solution which enables transparent and efficient access to on-line and near-line data through high latency networks. The solution is based on the joint use of the General Parallel File System (GPFS) and of the Tivoli Storage Manager (TSM). Both products, developed by IBM, are well known and extensively used in the HEP computing community. Owing to a new feature introduced in GPFS 3.5, so-called Active File Management (AFM), the definition of a single, geographically-distributed namespace, characterised by automated data flow management between different locations, becomes possible. As a practical example, we present the implementation of AFM-based remote data access between two data centres located in Bologna and Rome, demonstrating the validity of the solution for the use case of the AMS experiment, an astro-particle experiment supported by the INFN CNAF data centre with the large disk space requirements (more than 1.5 PB).
Published: 2015

23. First Experiences with CMS Data Storage on the GEMSS System at the INFN-CNAF Tier-1

Author: D. Andreotti, A. Sartirana, A. Cavalli, P. P. Ricci, S. Dal Pra, B Martelli, L. dell'Agnello, Elisabetta Ronchieri, A Prosperini, Riccardo Zappi, V. Sapunenko, A.C. Forti, L. Li Gioi, Daniele Bonacorsi, D Gregori, C. Grandi, and V. Vagnoni
Subjects: File system, Engineering, Large Hadron Collider, Database, business.industry, Scale test, Context (language use), computer.software_genre, Tier 1 network, Software deployment, Computer data storage, Operating system, IBM, business, computer
Abstract: A brand new Mass Storage System solution called “Grid-Enabled Mass Storage System” (GEMSS) -based on the Storage Resource Manager (StoRM) developed by INFN, on the General Parallel File System by IBM and on the Tivoli Storage Manager by IBM -has been tested and deployed at the INFNCNAF Tier-1 Computing Centre in Italy. After a successful stress test phase, the solution is now being used in production for the data custodiality of the CMS experiment at CNAF. All data previously recorded on the CASTOR system have been transferred to GEMSS. As final validation of the GEMSS system, some of the computing tests done in the context of the WLCG “Scale Test for the Experiment Program” (STEP’09) challenge were repeated in September-October 2009 and compared with the results previously obtained with CASTOR in June 2009. In this paper, the GEMSS system basics, the stress test activity and the deployment phase -as well as the reliability and performance of the system -are overviewed. The experiences in the use of GEMSS at CNAF in preparing for the first months of data taking of the CMS experiment at the Large Hadron Collider are also presented.
Published: 2011

24. Precise Measurement of the Neutron Magnetic Form FactorGMnin the Few-GeV2Region

Author: R. J. Feuerbach, J. P. Cummings, L. C. Smith, E. Munevar, R. De Masi, D. Keller, M. Kossov, B. S. Ishkhanov, I. Popa, K. S. Egiyan, G. Ricco, K. Mikhailov, L. Cheng, M. Khandaker, M. Garçon, J. Shaw, Michael Wood, P. Nadel-Turonski, Nikolay Shvedunov, M. R. Niroula, K. Hafidi, R. Nasseripour, S. McAleer, Friedrich Klein, B. P. Quinn, Brian Raue, V. S. Serov, L. Casey, F. X. Girod, Susan Taylor, Marco A. Huertas, M. Lowry, V. Sapunenko, D. P. Watts, L. C. Dennis, B. E. Bonner, Hartmuth Arenhövel, Dinko Pocanic, H. Egiyan, R. G. Fersch, H. Avakian, D. Doughty, B. B. Niczyporuk, G. S. Adams, S. Park, D. Sharov, N. Kalantarians, P. L. Cole, Sylvain Bouchigny, Sabine Jeschonnek, R. C. Minehart, Kei Moriya, D. Heddle, P. Rossi, J. Lachniet, H. G. Juengst, C. A. Meyer, N. Pivnyuk, K. Joo, W. J. Briscoe, B. L. Berman, A. Tkabladze, G. V. Fedotov, E. Pasyuk, D. Rowntree, A. Coleman, L. M. Qin, M. Y. Gabrielyan, S. E. Kuhn, S. A. Dytman, V. Crede, Y. Ilieva, J. R. Calarco, T. Mineeva, J. W. Price, M. J. Amaryan, C. Paterson, S. Strauch, M. MacCormick, A.V. Stavinsky, M. Klusman, I. Hleiqawi, V. P. Kubarovsky, K. P. Adhikari, S. L. Careccia, A. Empl, L. El Fassi, O. Pogorelko, B. Moreno, D. P. Weygand, J. Salamanca, R. Suleiman, M. E. McCracken, Elton Smith, K. L. Giovanetti, B. Asavapibhop, G. V. O'Rielly, Tsutomu Mibe, Larry Weinstein, Z. W. Zhao, J. W C McNabb, D. J. Tedeschi, D. Protopopescu, D. G. Jenkins, Barry Ritchie, M. Anghinolfi, James Mueller, S. Malace, S. A. Morrow, P. Rubin, I. Bedlinskiy, G. S. Mutchler, Konstantin Stopani, S. Pozdniakov, V. Gyurjyan, M. M. Ito, C. Djalali, Y. G. Sharabian, G. Rosner, T. Kageya, K. Livingston, D. S. Dale, X. Wei, R. Dickson, V. Kuznetsov, C. E. Hyde-Wright, H. Denizli, N. Guler, N. A. Baltzell, P. Mattione, K. A. Griffioen, M. S. Saini, A. V. Skabelin, P. Dragovitsch, J. Zhang, S. Barrow, E. De Sanctis, S. Niccolai, J. T. Goetz, E. Polli, H. Bagdasaryan, R. A. Miskimen, J. D. Kellie, B. McKinnon, Sergey Kuleshov, M. Bektasoglu, J. Hardie, M. Nozar, W. Kim, Laird Kramer, G. Niculescu, D. I. Sober, D. Branford, M. Guidal, R. A. Schumacher, H. Hakobyan, M. Mirazita, P. Khetarpal, C. Hanretty, J. M. Laget, M. Holtrop, Victor Mokeev, L. Graham, J. R. Johnstone, N. Gevorgyan, L. Guo, M. Ungaro, M. Osipenko, F. Sabatié, A. Daniel, K. Beard, Kalvir S. Dhuga, S. Bültmann, A. I. Ostrovidov, J. Yun, D. Cords, V. Batourine, T. A. Forest, A. Yegneswaran, A. C S Lima, A. Sandorfi, K. Park, R. Fatemi, S. Stepanyan, A. V. Vlassov, D. G. Ireland, Volker D. Burkert, A. S. Biselli, J. Pierce, Avraham Klein, B. Zhao, J. Langheinrich, R. De Vita, A. Fradi, S. S. Stepanyan, S. A. Philips, William Brooks, N. Markov, P. Konczykowski, B. E. Stokes, J. J. Manak, S. Anefalos Pereira, G. E. Dodge, H. Y. Lu, N. Dashyan, Maryam Moteabbed, P. V. Degtyarenko, K. V. Dharmawardane, I. Niculescu, D. Lawrence, D. Schott, F. W. Hersman, M. Battaglieri, N. Baillie, P. Stoler, K. Hicks, G. Asryan, O. P. Dzyubak, R. A. Niyazov, P. Corvisiero, R. Bradford, B. A. Mecking, K. Lukashin, E. Wolin, Gerard Gilfoyle, M. Guillo, D. Sokhan, W. Gohn, N. Hassall, M. Bellis, E. Golovatch, J. P. Ball, J. Hu, Y. Prok, D. S. Carman, S. Dhamija, M. D. Mestayer, L. Elouadrhiri, I. I. Strakovsky, E. L. Isupov, R. W. Gothe, G. Gavalian, S. Tkachenko, A. Deur, Michael L. Williams, J. Kuhn, N. Benmouna, J. P. Santoro, Andrei Afanasev, M. Ripani, D. G. Crabb, K. Y. Kim, Roy Thompson, Cynthia Marie Hadjidakis, S. Boiarinov, Michael Dugger, B. M. Preedom, Douglas Higinbotham, M. Yurov, Lorenzo Zana, H. S. Jo, C. Bookwalter, C. Salgado, Kwangsoo Kim, G. Riccardi, P. Eugenio, A. Starostin, M. Taiuti, Michael Vineyard, and P. Collins
Subjects: Physics, 010308 nuclear & particles physics, Scattering, Nuclear Theory, General Physics and Astronomy, Scintillator, 7. Clean energy, 01 natural sciences, Nuclear physics, Dipole, Deuterium, 0103 physical sciences, Magnetic form factor, Neutron detection, High Energy Physics::Experiment, Neutron, Nuclear Experiment, 010306 general physics, Electron scattering
Abstract: The neutron elastic magnetic form factor was extracted from quasielastic electron scattering on deuterium over the range Q;{2}=1.0-4.8 GeV2 with the CLAS detector at Jefferson Lab. High precision was achieved with a ratio technique and a simultaneous in situ calibration of the neutron detection efficiency. Neutrons were detected with electromagnetic calorimeters and time-of-flight scintillators at two beam energies. The dipole parametrization gives a good description of the data.
Published: 2009

25. Search for the Photoexcitation of Exotic Mesons in theπ+π+π−System

Author: M. Nozar, C. Salgado, D. P. Weygand, L. Guo, G. Adams, Ji Li, P. Eugenio, M. J. Amaryan, M. Anghinolfi, G. Asryan, H. Avakian, H. Bagdasaryan, N. Baillie, J. P. Ball, N. A. Baltzell, S. Barrow, M. Battaglieri, I. Bedlinskiy, M. Bektasoglu, M. Bellis, N. Benmouna, B. L. Berman, A. S. Biselli, L. Blaszczyk, B. E. Bonner, S. Bouchigny, S. Boiarinov, R. Bradford, D. Branford, W. J. Briscoe, W. K. Brooks, S. Bültmann, V. D. Burkert, C. Butuceanu, J. R. Calarco, S. L. Careccia, D. S. Carman, B. Carnahan, L. Casey, A. Cazes, S. Chen, L. Cheng, P. L. Cole, P. Collins, P. Coltharp, D. Cords, P. Corvisiero, D. Crabb, H. Crannell, V. Crede, J. P. Cummings, D. Dale, N. Dashyan, R. De Masi, R. De Vita, E. De Sanctis, P. V. Degtyarenko, H. Denizli, L. Dennis, A. Deur, K. V. Dharmawardane, K. S. Dhuga, R. Dickson, C. Djalali, G. E. Dodge, D. Doughty, M. Dugger, S. Dytman, O. P. Dzyubak, H. Egiyan, K. S. Egiyan, L. El Fassi, L. Elouadrhiri, R. Fatemi, G. Fedotov, R. J. Feuerbach, T. A. Forest, A. Fradi, H. Funsten, M. Garçon, G. Gavalian, N. Gevorgyan, G. P. Gilfoyle, K. L. Giovanetti, F. X. Girod, J. T. Goetz, R. W. Gothe, K. A. Griffioen, M. Guidal, M. Guillo, N. Guler, V. Gyurjyan, C. Hadjidakis, K. Hafidi, H. Hakobyan, C. Hanretty, J. Hardie, N. Hassall, D. Heddle, F. W. Hersman, K. Hicks, I. Hleiqawi, M. Holtrop, C. E. Hyde-Wright, Y. Ilieva, D. G. Ireland, B. S. Ishkhanov, E. L. Isupov, M. M. Ito, D. Jenkins, H. S. Jo, J. R. Johnstone, K. Joo, H. G. Juengst, N. Kalantarians, J. D. Kellie, M. Khandaker, W. Kim, A. Klein, F. J. Klein, M. Kossov, Z. Krahn, L. H. Kramer, V. Kubarovsky, J. Kuhn, S. E. Kuhn, S. V. Kuleshov, V. Kuznetsov, J. Lachniet, J. M. Laget, J. Langheinrich, D. Lawrence, K. Livingston, H. Y. Lu, M. MacCormick, N. Markov, P. Mattione, S. McAleer, B. McKinnon, J. W. C. McNabb, B. A. Mecking, S. Mehrabyan, M. D. Mestayer, C. A. Meyer, T. Mibe, K. Mikhailov, M. Mirazita, R. Miskimen, V. Mokeev, B. Moreno, K. Moriya, S. A. Morrow, M. Moteabbed, J. Mueller, E. Munevar, G. S. Mutchler, P. Nadel-Turonski, R. Nasseripour, S. Niccolai, G. Niculescu, I. Niculescu, B. B. Niczyporuk, M. R. Niroula, R. A. Niyazov, G. V. O’Rielly, M. Osipenko, A. I. Ostrovidov, K. Park, E. Pasyuk, C. Paterson, S. Anefalos Pereira, S. A. Philips, J. Pierce, N. Pivnyuk, D. Pocanic, O. Pogorelko, E. Polli, I. Popa, S. Pozdniakov, B. M. Preedom, J. W. Price, Y. Prok, D. Protopopescu, L. M. Qin, B. A. Raue, G. Riccardi, G. Ricco, M. Ripani, B. G. Ritchie, F. Ronchetti, G. Rosner, P. Rossi, P. D. Rubin, F. Sabatié, J. Salamanca, J. P. Santoro, V. Sapunenko, R. A. Schumacher, V. S. Serov, Y. G. Sharabian, D. Sharov, N. V. Shvedunov, A. V. Skabelin, E. S. Smith, L. C. Smith, D. I. Sober, D. Sokhan, A. Stavinsky, S. S. Stepanyan, S. Stepanyan, B. E. Stokes, P. Stoler, I. I. Strakovsky, S. Strauch, M. Taiuti, D. J. Tedeschi, U. Thoma, A. Tkabladze, S. Tkachenko, L. Todor, M. Ungaro, M. F. Vineyard, A. V. Vlassov, D. P. Watts, L. B. Weinstein, M. Williams, E. Wolin, M. H. Wood, A. Yegneswaran, L. Zana, J. Zhang, B. Zhao, and Z. W. Zhao
Subjects: Quantum chromodynamics, Physics, Particle physics, Meson, 010308 nuclear & particles physics, Partial wave analysis, Bremsstrahlung, General Physics and Astronomy, 01 natural sciences, 7. Clean energy, Nuclear physics, Excited state, 0103 physical sciences, Isobar, Production (computer science), 010306 general physics, Spin-½
Abstract: A search for exotic mesons in the $$\pi^{+}\pi^{+}\pi^{-}$$ system photoproduced by the charge exchange reaction $$\gamma p\to \pi^{+}\pi^{+}\pi^{-}(n)$$ was carried out by the CLAS collaboration at Jefferson Lab. A tagged-photon beam with energies in the 4.8 to 5.4 GeV range, produced through bremsstrahlung from a 5.744 GeV electron beam, was incident on a liquid-hydrogen target. A Partial Wave Analysis (PWA) was performed on a sample of 83,000 events, the highest such statistics to date in this reaction at these energies. The main objective of this study was to look for the photoproduction of an exotic $$J^{PC} = 1^{-+}$$ resonant state in the 1 to 2 GeV mass range. Our PWA analysis, based on the isobar model, shows production of the $$a_{2}(1320)$$ and the $$\pi_{2}(1670)$$ mesons, but no evidence for the $$a_{1}(1260)$$, nor the $$\pi_{1}(1600)$$ exotic state at the expected levels. An upper limit of 13.5 nb is determined for the exotic $$\pi_1(1600)$$ cross section, less than 2% of the $a_2(1320)
Published: 2009

26. Measurement of Directf0(980)Photoproduction on the Proton

Author: S. Park, Sylvain Bouchigny, V. Crede, J. R. Calarco, E. Wolin, C. E. Hyde, R. A. Schumacher, V. Sapunenko, Dinko Pocanic, P. Nadel-Turonski, L. Casey, V. Mokeev, D. Lawrence, J. P. Cummings, H. G. Juengst, B. E. Stokes, Cynthia Marie Hadjidakis, J. P. Ball, D. S. Carman, A. Fradi, A. V. Vlassov, P. Konczykowski, M. J. Amaryan, S. Dhamija, Michael Dugger, K. Livingston, D. S. Dale, T. Lee, Maryam Moteabbed, M. Kossov, S. E. Kuhn, L. Graham, Ashot Gasparian, B. B. Niczyporuk, C. I O Gordon, M. MacCormick, R. W. Gothe, Z. W. Zhao, R. Dickson, N. Gevorgyan, T. Kageya, H. Avakian, I. Hleiqawi, K. V. Dharmawardane, A.V. Stavinsky, J. Donnelly, G. Asryan, N. Pivnyuk, D. G. Crabb, J. Kuhn, M. E. McCracken, R. De Vita, S. Strauch, E. Clinton, S. Bültmann, S. L. Careccia, D. G. Jenkins, O. P. Dzyubak, D. P. Watts, H. Egiyan, Gerard Gilfoyle, G. Ricco, Lorenzo Zana, J. P. Santoro, C. Tur, L. Gan, Tsutomu Mibe, W. Gohn, T. A. Forest, D. J. Tedeschi, N. Markov, D. Sokhan, D. Sharov, W. Kim, S. Anefalos Pereira, S. Stepanyan, G. Niculescu, M. Yurov, J. Goett, R. A. Miskimen, I. Bedlinskiy, B. McKinnon, M. Y. Gabrielyan, J. Pierce, K. L. Giovanetti, F. X. Girod, Sergey Kuleshov, Avraham Klein, Shifeng Chen, N. Guler, E. Golovatch, Friedrich Klein, Larry Weinstein, N. A. Baltzell, G. E. Dodge, P. Khetarpal, K. A. Stopani, Brian Raue, D. Keller, H. Y. Lu, M. Nozar, D. Branford, J. Salamanca, H. S. Jo, C. Bookwalter, E. De Sanctis, L. Lesniak, G. Riccardi, J. M. Laget, V. V. Mochalov, P. Mattione, K. A. Griffioen, M. Aghasyan, X. Wei, V. Kuznetsov, M. S. Saini, P. V. Degtyarenko, A. I. Ostrovidov, D. I. Sober, A. Sandorfi, K. Park, P. Eugenio, Adam P. Szczepaniak, V. Batourine, C. Hanretty, A. Starostin, M. Guidal, N. Dashyan, M. Taiuti, W. J. Briscoe, E. Pasyuk, H. Hakobyan, S. A. Morrow, G. Rosner, J. T. Goetz, M. Mirazita, C. Djalali, Paolo Rossi, M. Khandaker, L. Bibrzycki, I. Niculescu, J. Lachniet, A. Tkabladze, Y. Ilieva, J. W. Price, M. Holtrop, R. A. Niyazov, Elton Smith, D. G. Ireland, A. Daniel, A. Teymurazyan, I. I. Strakovsky, G. Gavalian, N. Hassall, M. Bellis, P. Ambrozewicz, P. Collins, B. Zhao, R. De Masi, S. Tkachenko, D. Schott, M. Ripani, D. Doughty, P. Stoler, J. J. Melone, S. Niccolai, Z. Krahn, Volker D. Burkert, A. S. Biselli, M. Anghinolfi, C. Salgado, N. Benmouna, J. Langheinrich, S. S. Stepanyan, D. Heddle, J. D. Kellie, A. Deur, N. Baillie, T. Mineeva, S. Malace, Mark W. Paris, J. R. Johnstone, Hall Crannell, M. Osipenko, V. P. Kubarovsky, Y. G. Sharabian, Laird Kramer, L. Cheng, W. K. Brooks, J. Hardie, F. W. Hersman, R. S. Hakobyan, L. Guo, M. Ungaro, B. Moreno, O. Pogorelko, G. S. Mutchler, K. Hicks, Nikolay Shvedunov, D. Protopopescu, B. L. Berman, K. S. Egiyan, L. El Fassi, S. Pozdniakov, M. Garçon, Michael Wood, K. Mikhailov, K. Hafidi, V. S. Serov, M. Battaglieri, N. Kalantarians, R. Bradford, B. A. Mecking, R. Nasseripour, K. Joo, A. Yegneswaran, Michael Vineyard, V. Gyurjyan, J. Zhang, H. Bagdasaryan, L. Todor, R. G. Fersch, C. Paterson, Ji Li, P. L. Cole, M. D. Mestayer, E. L. Isupov, Michael L. Williams, M. M. Ito, S. Boiarinov, F. Sabatié, L. C. Smith, E. Munevar, B. S. Ishkhanov, M. R. Niroula, M. Lowry, Latifa Elouadrhiri, R. C. Minehart, Kei Moriya, C. A. Meyer, G. V. Fedotov, K. P. Adhikari, D. P. Weygand, O. Glamazdin, Alexei V. Klimenko, Y. Prok, Barry Ritchie, and I. Nakagawa
Subjects: Physics, Particle physics, Proton, Meson, 010308 nuclear & particles physics, Partial wave analysis, Hadron, General Physics and Astronomy, Resonance, 01 natural sciences, 7. Clean energy, Nuclear physics, Particle decay, Pion, 0103 physical sciences, 010306 general physics, Nucleon
Abstract: We report on the results of the first measurement of exclusive f{sub 0}(980) meson photoproduction on protons for E{sub {gamma}}=3.0-3.8 GeV and -t=0.4-1.0 GeV{sup 2}. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The resonance was detected via its decay in the {pi}{sup +}{pi}{sup -} channel by performing a partial wave analysis of the reaction {gamma}p{yields}p{pi}{sup +}{pi}{sup -}. Clear evidence of the f{sub 0}(980) meson was found in the interference between P and S waves at M{sub {pi}{sup +}}{sub {pi}{sup -}}{approx}1 GeV. The S-wave differential cross section integrated in the mass range of the f{sub 0}(980) was found to be a factor of about 50 smaller than the cross section for the {rho} meson. This is the first time the f{sub 0}(980) meson has been measured in a photoproduction experiment.
Published: 2009

27. Electroproduction ofpπ+π−off protons at0.2<Q2<0.6GeV2and1.3<W<1.57GeV with the CLAS detector

Author: P. Stoler, N. A. Baltzell, V. Crede, K. Hicks, J. R. Calarco, K. A. Griffioen, K. S. Egiyan, J. D. Kellie, C. Paterson, H. Denizli, S. Strauch, M. Klusman, M. Guidal, J. W C McNabb, K. Livingston, Nikolay Shvedunov, G. S. Mutchler, R. Dickson, Shifeng Chen, M. Osipenko, M. Holtrop, G. E. Dodge, V. Gyurjyan, P. Eugenio, P. V. Degtyarenko, Laird Kramer, J. Donnelly, G. Asryan, C. E. Hyde, O. P. Dzyubak, M. Taiuti, Marco A. Huertas, G. Rosner, T. Mineeva, J. Zhang, N. Guler, F. X. Girod, J. Langheinrich, I. Niculescu, V. Batourine, B. Carnahan, R. A. Niyazov, E. De Sanctis, Hovhannes Baghdasaryan, Sylvain Bouchigny, L. C. Smith, J. T. Goetz, J. P. Cummings, D. Lawrence, A.V. Stavinsky, B. B. Niczyporuk, P. Corvisiero, L. Guo, P. Rossi, B. S. Ishkhanov, M. Ungaro, R. A. Miskimen, B. McKinnon, H. G. Juengst, Susan Taylor, E. Wolin, D. I. Sober, J. W. Price, Konstantin Stopani, D. J. Tedeschi, V. Sapunenko, N. Pivnyuk, K. Mikhailov, Y. Prok, D. Branford, Dinko Pocanic, M. Mirazita, H. Egiyan, E. Golovatch, William Brooks, J. M. Laget, L. Todor, S. E. Kuhn, R. Fatemi, J. P. Ball, I. Bedlinskiy, Sergey Kuleshov, Rakhsha Nasseripour, Hall Crannell, M. Bektasoglu, A. Yegneswaran, B. E. Stokes, D. Protopopescu, S. Pozdniakov, A. V. Vlassov, K. V. Dharmawardane, D. S. Carman, G. S. Adams, C. Tur, T. Lee, G. Ricco, K. Joo, J. Kuhn, D. G. Jenkins, A. I. Ostrovidov, Roy Thompson, G. V. O'Rielly, K. Park, R. De Vita, R. A. Schumacher, Elton Smith, R. J. Feuerbach, Victor Mokeev, J. Shaw, Y. Ilieva, S. A. Morrow, C. Djalali, G. Niculescu, M. Anghinolfi, Michael Wood, D. G. Ireland, D. G. Crabb, M. D. Mestayer, P. Coltharp, Friedrich Klein, James Mueller, N. Dashyan, S. Bültmann, T. A. Forest, Brian Raue, G. Gavalian, N. Hassall, M. Bellis, M. Guillo, S. Stepanyan, S. Niccolai, M. M. Ito, E. L. Isupov, Volker D. Burkert, J. Pierce, Avraham Klein, A. S. Biselli, P. D. Rubin, J. Hardie, J. Hu, P. Ambrozewicz, M. Battaglieri, V. S. Serov, L. C. Dennis, Michael L. Williams, B. E. Bonner, R. Bradford, B. A. Mecking, S. Tkachenko, N. Benmouna, F. Sabatié, Y. G. Sharabian, H. Avakian, Kwangsoo Kim, C. Butuceanu, M. Ripani, N. Markov, S. Boiarinov, D. Sharov, Cynthia Marie Hadjidakis, Michael Dugger, H. O. Funsten, E. Pasyuk, S. A. Dytman, Latifa Elouadrhiri, R. C. Minehart, Kei Moriya, C. A. Meyer, A. Tkabladze, G. V. Fedotov, Michael Vineyard, D. P. Weygand, Alexei V. Klimenko, V. P. Kubarovsky, Barry Ritchie, O. Pogorelko, Lorenzo Zana, J. P. Santoro, H. S. Jo, D. Doughty, C. Salgado, M. E. McCracken, P. Nadel-Turonski, Tsutomu Mibe, M. Khandaker, N. Gevorgyan, Z. Krahn, J. Lachniet, N. Baillie, Gerard Gilfoyle, D. Rowntree, M. J. Amaryan, R. W. Gothe, I. Hleiqawi, K. Y. Kim, S. L. Careccia, P. L. Cole, K. L. Giovanetti, B. Asavapibhop, Larry Weinstein, F. W. Hersman, and W. Kim
Subjects: Baryon, Physics, Nuclear and High Energy Physics, Particle physics, Pion, Meson, Hadron, Elementary particle, Invariant mass, Sensitivity (control systems), Nucleon
Abstract: This paper reports on the most comprehensive data set obtained on differential and fully integrated cross sections for the process ep{yields}e{sup '}p{pi}{sup +}{pi}{sup -}. The data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the as yet unexplored kinematic region of photon virtuality 0.2
Published: 2009

28. Measurement of semi-inclusive pi+ electroproduction off the proton

Author: L. C. Smith, E. Munevar, M. H. Wood, Y. Ilieva, M. E. McCracken, P. Nadel-Turonski, E. Wolin, R. J. Feuerbach, B. S. Ishkhanov, G. E. Dodge, Tsutomu Mibe, P. V. Degtyarenko, J. P. Ball, Y. Prok, D. S. Carman, M. R. Niroula, Alexander Ilyichev, O. P. Dzyubak, I. I. Strakovsky, Paolo Rossi, K. S. Egiyan, P. L. Cole, Z. W. Zhao, J. Lachniet, A. Tkabladze, W. Kim, I. Niculescu, R. A. Niyazov, D. G. Crabb, R. S. Hakobyan, L. El Fassi, Elton Smith, A. Deur, G. Niculescu, R. De Masi, B. L. Berman, J. Kuhn, B. McKinnon, W. K. Brooks, G. P. Gilfoyle, K. Livingston, R. Fatemi, N. Markov, A. V. Vlassov, J. P. Cummings, M. Anghinolfi, G. Ricco, B. Zhao, D. J. Tedeschi, S. Niccolai, R. Dickson, Ji Li, Y. G. Sharabian, S. Strauch, D. P. Watts, H. Egiyan, L. M. Qin, C. Paterson, L. Zana, D. Branford, J. M. Laget, M. Khandaker, G. Riccardi, N. Hassall, M. Bellis, Cynthia Marie Hadjidakis, R. De Vita, A. I. Ostrovidov, K. A. Griffioen, N. Guler, F. W. Hersman, J. Hardie, C. Butuceanu, M. J. Amaryan, M. Kossov, Shifeng Chen, E. N. Golovach, Volker D. Burkert, A. S. Biselli, Michael Dugger, J. Langheinrich, H. O. Funsten, H. G. Juengst, Luca Trentadue, M. MacCormick, I. Hleiqawi, M. D. Mestayer, C. Djalali, H. Denizli, P. Eugenio, S. Dytman, A. V. Skabelin, S. L. Careccia, I. Popa, P. Coltharp, R. A. Schumacher, P. Mattione, M. Osipenko, S. Barrow, M. Taiuti, A.V. Stavinsky, S. Anefalos Pereira, P. D. Rubin, R. W. Gothe, Laird Kramer, E. L. Isupov, D. Lawrence, D. Sokhan, M. M. Ito, H. Hakobyan, A. Cazes, J. R. Calarco, C. I O Gordon, K. L. Giovanetti, S. Mehrabyan, Alexei V. Klimenko, J. T. Goetz, R. Miskimen, C. Hanretty, G. V. O'Rielly, E. Polli, Michael L. Williams, Larry Weinstein, M. Mirazita, Kalvir S. Dhuga, J. D. Kellie, P. Collins, Friedrich Klein, F. Sabatié, Nikolay Shvedunov, J. J. Melone, V. Sapunenko, Sylvain Bouchigny, S. Bültmann, L. Todor, Barry Ritchie, Dinko Pocanic, Victor Mokeev, Brian Raue, G. Asryan, E. De Sanctis, M. Battaglieri, I. Bedlinskiy, V. A. Drozdov, S. Stepanyan, S. E. Kuhn, N. A. Baltzell, D. Protopopescu, S. Pozdniakov, M. Garçon, M. F. Vineyard, J. Pierce, Avraham Klein, Z. Krahn, N. Dashyan, S. Boiarinov, U. Thoma, D. I. Sober, R. Bradford, N. Kalantarians, Latifa Elouadrhiri, V. Gyurjyan, G. S. Mutchler, D. G. Ireland, V. Crede, N. Baillie, B. B. Niczyporuk, R. C. Minehart, Kei Moriya, S. McAleer, N. Pivnyuk, B. E. Stokes, J. Napolitano, G. S. Adams, J. Zhang, B. M. Preedom, F. X. Girod, L. Blaszczyk, H. Bagdasaryan, J. P. Santoro, C. Tur, C. A. Meyer, L. Guo, M. Ungaro, G. Gavalian, J. Donnelly, S. Tkachenko, D. Heddle, J. Salamanca, N. Benmouna, G. V. Fedotov, M. Ripani, J. W C McNabb, D. Jenkins, R. Nasseripour, S. A. Morrow, K. Joo, Maryam Moteabbed, Bernhard Mecking, K. V. Dharmawardane, A. Yegneswaran, Atilla Gonenc, P. Ambrozewicz, J. W. Price, M. Holtrop, D. P. Weygand, P. Corvisiero, H. S. Jo, Gerald Feldman, Federico A. Ceccopieri, C. Salgado, G. Rosner, M. Guillo, K. Mikhailov, M. Guidal, H. Y. Lu, C. E. Hyde-Wright, P. Stoler, Sergey Kuleshov, M. Bektasoglu, M. Nozar, K. Hicks, S. S. Stepanyan, S. A. Philips, J. Mueller, K. Hafidi, V. S. Serov, K. Park, V. P. Kubarovsky, O. Pogorelko, L. C. Dennis, B. E. Bonner, H. Avakian, W. J. Briscoe, E. Pasyuk, D. Doughty, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, CLAS, and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Particle physics, Nuclear and High Energy Physics, Proton, DEEP-INELASTIC-SCATTERING, TARGET FRAGMENTATION REGION, TRANSVERSE-MOMENTUM, PARTON DISTRIBUTIONS, AZIMUTHAL ASYMMETRY, PION ELECTROPRODUCTION, CHARGED HADRONS, HARD PROCESSES, LEADING ORDER, CROSS-SECTION, TARGET FRAGMENTATION REGION, Hadron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Spectral line, Nuclear physics, Pion, Factorization, 0103 physical sciences, 010306 general physics, Nuclear Experiment, PION ELECTROPRODUCTION, Physics, DEEP-INELASTIC-SCATTERING, 010308 nuclear & particles physics, LEADING ORDER, TRANSVERSE-MOMENTUM, Azimuth, Diquark, CHARGED HADRONS, HARD PROCESSES, PARTON DISTRIBUTIONS, Cathode ray, AZIMUTHAL ASYMMETRY, High Energy Physics::Experiment, CROSS-SECTION
Abstract: Semi-inclusive {pi}{sup +} electroproduction on protons has been measured with the CLAS detector at Jefferson Lab. The measurement was performed on a liquid-hydrogen target using a 5.75 GeV electron beam. The complete five-fold differential cross sections were measured over a wide kinematic range including the complete range of azimuthal angles between hadronic and leptonic planes, {phi}, enabling us to separate the {phi}-dependent terms. Our measurements of the {phi}-independent term of the cross section at low Bjorken x were found to be in fairly good agreement with pQCD calculations. Indeed, the conventional current fragmentation calculation can account for almost all of the observed cross section, even at small {pi}{sup +} momentum. The measured center-of-momentum spectra are in qualitative agreement with high-energy data, which suggests a surprising numerical similarity between the spectator diquark fragmentation in the present reaction and the antiquark fragmentation measured in e{sup +}e{sup -} collisions. We have observed that the two {phi}-dependent terms of the cross section are small. Within our precision the cos2{phi} term is compatible with zero, except for the low-z region, and the measured cos{phi} term is much smaller in magnitude than the sum of the Cahn and Berger effects.
Published: 2009

29. Electroexcitation of the Roper resonance for1.7<Q2<4.5GeV2ine→p→enπ+

Author: B. Zhao, F. W. Hersman, Marco Ripani, S. Dhamija, R. W. Gothe, K. Y. Kim, J. Kuhn, J. P. Santoro, E. De Sanctis, Latifa Elouadrhiri, B. M. Preedom, P. Eugenio, R. C. Minehart, Kei Moriya, D. I. Sober, M. Taiuti, G. Rosner, C. A. Meyer, M. Battaglieri, G. V. Fedotov, P. Collins, J. J. Melone, Lorenzo Zana, R. Bradford, K. Lukashin, J. Shaw, V. Batourine, D. P. Weygand, H. Hakobyan, Friedrich Klein, H. S. Jo, Michael Wood, K. Hafidi, Brian Raue, Gerald Feldman, Elton Smith, R. Fatemi, V. S. Serov, A. V. Vlassov, T. Lee, M. Anghinolfi, P. Coltharp, James Mueller, I. I. Strakovsky, N. A. Baltzell, R. De Vita, P. D. Rubin, A. Cazes, Maryam Moteabbed, C. Salgado, Bernhard Mecking, Y. G. Sharabian, A. Deur, K. A. Griffioen, K. S. Egiyan, K. V. Dharmawardane, Baile Zhang, Alexei V. Klimenko, S. Anefalos Pereira, Z. Krahn, W. K. Brooks, Shifeng Chen, J. D. Kellie, Y. Prok, N. Hassall, M. Bellis, J. Langheinrich, Barry Ritchie, N. Baillie, P. Mattione, M. S. Saini, L. C. Dennis, B. E. Bonner, S. S. Stepanyan, S. A. Philips, R. A. Miskimen, B. McKinnon, H. Avakian, J. T. Goetz, E. Polli, B. L. Berman, D. Sharov, M. Mirazita, D. Branford, K. Livingston, D. S. Dale, Ji Li, L. M. Qin, J. M. Laget, H. Denizli, N. Gevorgyan, C. Paterson, G. Gavalian, W. J. Briscoe, E. Pasyuk, S. Tkachenko, M. D. Mestayer, S. A. Dytman, J. Donnelly, G. Asryan, A. V. Skabelin, N. Benmouna, Gerard Gilfoyle, O. P. Dzyubak, R. A. Niyazov, E. L. Isupov, A. Fradi, D. Sokhan, M. Guillo, V. Crede, Michael L. Williams, W. Gohn, N. Markov, V. Sapunenko, Dinko Pocanic, J. R. Calarco, P. Corvisiero, E. Golovatch, S. Boiarinov, S. E. Kuhn, Charles Hyde, V. P. Kubarovsky, O. Pogorelko, C. Tur, M. J. Amaryan, M. MacCormick, I. Hleiqawi, R. Nasseripour, S. L. Careccia, S. McAleer, F. X. Girod, Laird Kramer, B. E. Stokes, G. S. Adams, J. P. Cummings, Cynthia Marie Hadjidakis, G. E. Dodge, H. Y. Lu, K. L. Giovanetti, L. Blaszczyk, P. V. Degtyarenko, M. Kossov, V. Gyurjyan, K. Joo, I. Popa, Sergey Kuleshov, M. Bektasoglu, Michael Dugger, D. Heddle, M. Nozar, P. Stoler, I. Niculescu, D. Lawrence, J. Zhang, R. De Masi, D. Schott, S. A. Morrow, C. Djalali, R. A. Schumacher, M. Guidal, Larry Weinstein, K. Hicks, M. Holtrop, L. Graham, H. Bagdasaryan, C. I O Gordon, P. Ambrozewicz, S. Bültmann, L. Morand, T. A. Forest, S. Stepanyan, J. Pierce, Avraham Klein, K. Mikhailov, L. Cheng, Nikolay Shvedunov, A. I. Ostrovidov, L. Casey, A. C S Lima, K. Park, N. Kalantarians, B. B. Niczyporuk, D. G. Ireland, Michael Vineyard, N. Pivnyuk, Giovanni Ricco, Atilla Gonenc, E. Wolin, Volker D. Burkert, A. S. Biselli, J. P. Ball, D. S. Carman, D. G. Crabb, J. Salamanca, J. W C McNabb, M. Yurov, J. W. Price, S. Mehrabyan, C. Bookwalter, G. Riccardi, H. Funsten, P. Nadel-Turonski, C. Butuceanu, Tsutomu Mibe, N. Dashyan, K. Hafnaoui, C. Hanretty, G. V. O'Rielly, J. R. Johnstone, Z. W. Zhao, D. Keller, Paolo Rossi, D. G. Jenkins, J. Lachniet, A. Tkabladze, S. Park, Sylvain Bouchigny, D. Rowntree, M. M. Ito, R. S. Hakobyan, L. El Fassi, M. Khandaker, H. G. Juengst, A.V. Stavinsky, D. J. Tedeschi, V. Mokeev, I. Bedlinskiy, L. C. Smith, E. Munevar, B. S. Ishkhanov, M. R. Niroula, V. Kuznetsov, S. Strauch, R. Suleiman, L. Guo, G. S. Mutchler, M. Ungaro, S. Niccolai, J. Hardie, D. Doughty, W. Kim, D. P. Watts, G. Niculescu, J. Yun, D. Cords, H. Egiyan, T. Takeuchi, A. Yegneswaran, M. Osipenko, F. Sabatié, Kalvir S. Dhuga, M. Y. Gabrielyan, R. Dickson, R. J. Feuerbach, N. Guler, Inna Aznauryan, P. L. Cole, S. Barrow, L. Todor, D. Protopopescu, S. Pozdniakov, M. Garçon, Y. Ilieva, and B. Moreno
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Roper resonance, Meson production, 010308 nuclear & particles physics, State (functional analysis), 01 natural sciences, Helicity, Baryon, 0103 physical sciences, Pi, Isobar, 010306 general physics, Ground state
Abstract: The helicity amplitudes of the electroexcitation of the Roper resonance are extracted for $1.7l{Q}^{2}l4.5\phantom{\rule{0.3em}{0ex}}{\mathrm{GeV}}^{2}$ from recent high precision JLab-CLAS cross section and longitudinally polarized beam asymmetry data for ${\ensuremath{\pi}}^{+}$ electroproduction on protons at $W=1.15\ensuremath{-}1.69$ GeV. The analysis is made using two approaches, dispersion relations and a unitary isobar model, which give consistent ${Q}^{2}$ behavior of the helicity amplitudes for the ${\ensuremath{\gamma}}^{*}p\ensuremath{\rightarrow}$N(1440)P${}_{11}$ transition. It is found that the transverse helicity amplitude ${A}_{1/2}$, which is large and negative at ${Q}^{2}=0$, becomes large and positive at ${Q}^{2}\ensuremath{\simeq}2\phantom{\rule{0.3em}{0ex}}{\mathrm{GeV}}^{2}$, and then drops slowly with ${Q}^{2}$. The longitudinal helicity amplitude ${S}_{1/2}$, which was previously found from CLAS $\stackrel{\ensuremath{\rightarrow}}{e}p\ensuremath{\rightarrow}\mathit{ep}{\ensuremath{\pi}}^{0},\mathit{en}{\ensuremath{\pi}}^{+}$ data to be large and positive at ${Q}^{2}=0.4,0.65\phantom{\rule{0.3em}{0ex}}{\mathrm{GeV}}^{2}$, drops with ${Q}^{2}$. Available model predictions for ${\ensuremath{\gamma}}^{*}p\ensuremath{\rightarrow}$N(1440)P${}_{11}$ allow us to conclude that these results provide strong evidence in favor of N(1440)P${}_{11}$ as a first radial excitation of the $3q$ ground state. The results of the present paper also confirm the conclusion of our previous analysis for ${Q}^{2}l1$ GeV${}^{2}$ that the presentation of N(1440)P${}_{11}$ as a q$^{3}\mathrm{G}$ hybrid state is ruled out.
Published: 2008

30. First measurement of target and double spin asymmetries fore→p→→epπ0in the nucleon resonance region above theΔ(1232)

Author: F. X. Girod, L. Blaszczyk, Lorenzo Zana, N. Dashyan, H. Hakobyan, E. Munevar, B. Zhao, H. S. Jo, B. S. Ishkhanov, D. Keller, V. Crede, J. W. Price, William Brooks, C. Salgado, J. Kuhn, J. P. Santoro, E. Wolin, J. R. Calarco, J. P. Ball, Y. Prok, D. S. Carman, M. Yurov, G. Gavaliann, D. G. Crabb, J. Langheinrich, S. S. Stepanyan, C. Bookwalter, C. Butuceanu, Shifeng Chen, W. Kim, M. Khandaker, M. R. Niroula, H. Avakian, V. Gyurjyan, R. A. Schumacher, Barry Ritchie, S. A. Morrow, H. G. Juengst, M. Kossov, C. Djalali, D. Sharov, A. Fradi, S. Tkachenko, Maryam Moteabbed, L. Graham, F. Sabatié, P. Eugenio, J. Zhang, Bernhard Mecking, N. Benmouna, S. Dhamija, M. Ripani, I. I. Strakovsky, D. P. Watts, H. Bagdasaryan, A. Tkabladze, M. Taiuti, G. Niculescu, H. Egiyan, S. Bültmann, L. Todor, M. S. Saini, S. Strauch, M. D. Mestayer, A.V. Stavinsky, K. Mikhailov, Z. W. Zhao, T. A. Forest, R. W. Gothe, J. T. Goetz, M. J. Amaryan, G. Ricco, D. J. Tedeschi, E. L. Isupov, D. G. Jenkins, D. Protopopescu, S. Stepanyan, P. Collins, V. Sapunenko, M. MacCormick, I. Hleiqawi, A. Deur, Latifa Elouadrhiri, Michael L. Williams, N. Hassall, M. Bellis, J. Pierce, Kei Moriya, Avraham Klein, Michael Dugger, S. L. Careccia, I. Bedlinskiy, S. Park, C. A. Meyer, N. Markov, L. Casey, W. J. Briscoe, S. Pozdniakov, M. Garçon, G. S. Mutchler, G. V. Fedotov, C. Hanretty, S. Boiarinov, N. A. Baltzell, G. Rosner, B. L. Berman, S. E. Kuhn, E. Pasyuk, K. L. Giovanetti, P. Rossi, V. Kuznetsov, Friedrich Klein, G. E. Dodge, H. Y. Lu, B. B. Niczyporuk, Larry Weinstein, K. A. Griffioen, Brian Raue, E. De Sanctis, P. V. Degtyarenko, M. Battaglieri, Victor Mokeev, J. R. Johnstone, D. Doughty, N. Pivnyuk, L. Guo, P. Mattione, R. J. Feuerbach, L. Cheng, C. Paterson, M. Ungaro, Nikolay Shvedunov, L. El Fassi, I. Niculescu, R. A. Niyazov, D. P. Weygand, R. Bradford, D. Lawrence, Elton Smith, J. D. Kellie, J. Lachniet, D. I. Sober, R. De Masi, D. Schott, S. Niccolai, M. F. Vineyard, P. Stoler, R. Nasseripour, N. Kalantarians, J. Salamanca, K. Joo, Y. G. Sharabian, P. Coltharp, J. W C McNabb, A. V. Vlassov, W. Gohn, Z. Krahn, V. P. Kubarovsky, B. E. Stokes, R. G. Fersch, K. Hicks, A. Yegneswaran, M. M. Ito, O. Pogorelko, Y. Ilieva, N. Baillie, R. De Vita, B. McKinnon, P. L. Cole, D. Branford, S. Anefalos Pereira, G. Asryan, O. P. Dzyubak, M. Osipenko, M. Mirazita, J. M. Laget, N. Gevorgyan, P. Nadel-Turonski, Tsutomu Mibe, Michael Wood, K. Hafidi, P. Bosted, Gerard Gilfoyle, B. Moreno, D. Sokhan, V. S. Serov, K. Livingston, D. S. Dale, R. Dickson, A. I. Ostrovidov, K. Park, N. Guler, D. G. Ireland, Volker D. Burkert, A. S. Biselli, M. Guidal, M. Holtrop, C. E. Hyde-Wright, Sergey Kuleshov, and M. Nozar
Subjects: Physics, Nuclear and High Energy Physics, Roper resonance, Particle physics, Proton, 010308 nuclear & particles physics, media_common.quotation_subject, Coupling (probability), 01 natural sciences, Resonance (particle physics), Asymmetry, Nuclear physics, 0103 physical sciences, Invariant mass, 010306 general physics, Nucleon, Spin (physics), media_common
Abstract: DOI: http://dx.doi.org/10.1103/PhysRevC.78.045204 The exclusive channel polarized proton(polarized e,e prime p)pi0 was studied in the first and second nucleon resonance regions in the Q2 range from 0.187 to 0.770 GeV2 at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). Longitudinal target and beam-target asymmetries were extracted over a large range of center-of-mass angles of the pi0 and compared to the unitary isobar model MAID, the dynamic model by Sato and Lee, and the dynamic model DMT. A strong sensitivity to individual models was observed, in particular for the target asymmetry and in the higher invariant mass region. This data set, once included in the global fits of the above models, is expected to place strong constraints on the electrocoupling amplitudes A_{1/2} and S_{1/2} for the Roper resonance N(1400)P11, and the N(1535)S11 and N(1520)D13 states.
Published: 2008

31. A novel approach for mass storage data custodial

Author: L. Magnoni, M. Mazzucato, Elisabetta Ronchieri, Riccardo Zappi, V. Sapunenko, D Vitlacil, B Martelli, L. dell'Agnello, V. Vagnoni, P. P. Ricci, D. Gregori, A. Carbone, and Antonia Ghiselli
Subjects: File system, Storage area network, Large Hadron Collider, Grid computing, Magnetic tape data storage, Database, Computer science, Interface (computing), Operating system, Petabyte, computer.software_genre, computer, Mass storage
Abstract: The mass storage challenge for the Large Hadron Collider (LHC) experiments is still nowadays a critical issue for the various Tier-1 computing centres and the Tier-0 centre involved in the custodial and analysis of the data produced by the experiments. In particular, the requirements for the tape mass storage systems are quite strong, amounting to several PetaBytes of data that should be available for near-line access at any time. Besides the solutions already widely employed by the High Energy Physics community so far, an interesting new option showed up recently. It is based on the interaction between the General Parallel File System (GPFS) and the Tivoli Storage Manager (TSM) by IBM. The new features introduced in GPFS version 3.2 allow to inteface GPFS with tape storage managers. We implemented such an interface for TSM, and performed various performance studies on a pre-production system. Together with the StoRM SRM interface, developed as a joint collaboration between INFN-CNAF and ICTP-Trieste, this solution can fulfill all the requirements of a Tier-1 WLCG centre. The first StoRM-GPFS-TSM based system has now entered its production phase at CNAF, presently adopted by the LHCb experiment. We will describe the implementation of the interface and the prototype test-bed, and we will discuss the results of some tests.
Published: 2008

32. A comparison of data-access platforms for the computing of BaBar experiment at the Italian Tier1

Author: V. Sapunenko, L. Li Gioi, D. Andreotti, Eleonora Luppi, and Armando Fella
Subjects: Storage area network, Data access, Large Hadron Collider, Database, Grid computing, Group method of data handling, Computer science, Scalability, Operating system, BaBar experiment, Context (language use), computer.software_genre, computer
Abstract: Performance, reliability and scalability in data access are key issues in the context of Grid computing and High Energy Physics (HEP) data analysis. We present the technical details and the results of a large scale validation and performance measurement achieved at the INFN Tier1, the central computing facility of the Italian National Institute for Nuclear Research (INFN). The aim of this work is the evaluation of data access activity during analysis tasks within BaBar computing model against two of the most used data handling systems in HEP scenario: GPFS and Scalla/Xrootd.
Published: 2008

33. Electroproduction ofϕ(1020)mesons at1.4⩽Q2⩽3.8GeV2measured with the CLAS spectrometer

Author: M. Guidal, R. Nasseripour, M. Holtrop, I. I. Strakovsky, R. J. Feuerbach, G. V. O'Rielly, Cynthia Marie Hadjidakis, B. Zhao, Z. W. Zhao, D. G. Jenkins, Alexei V. Klimenko, R. De Masi, A. Deur, Michael Dugger, H. O. Funsten, Michael Wood, K. Hafidi, N. Dashyan, B. E. Stokes, G. S. Adams, Barry Ritchie, P. L. Cole, B. M. Preedom, V. S. Serov, C. E. Hyde-Wright, S. McAleer, J. Langheinrich, S. S. Stepanyan, S. A. Philips, L. Blaszczyk, G. Ricco, J. Ball, F. W. Hersman, Sergey Kuleshov, Lorenzo Zana, J. P. Santoro, M. Bektasoglu, M. Nozar, M. Garçon, Elton Smith, M. Battaglieri, J. Salamanca, J. Lachniet, A. Tkabladze, Latifa Elouadrhiri, P. Coltharp, H. Hakobyan, F. Sabatié, H. S. Jo, K. Livingston, D. S. Dale, J. W C McNabb, J. R. Ficenec, N. A. Baltzell, V. Kuznetsov, R. Bradford, R. C. Minehart, Kei Moriya, C. A. Meyer, J. W. Price, M. M. Ito, S. Strauch, V. Mokeev, C. Salgado, L. Cheng, B. L. Berman, L. M. Qin, D. P. Watts, H. Egiyan, K. A. Griffioen, J. P. Cummings, V. Gyurjyan, G. V. Fedotov, S. A. Morrow, M. Anghinolfi, E. De Sanctis, V. P. Kubarovsky, D. Keller, Nikolay Shvedunov, Friedrich Klein, R. Dickson, James Mueller, C. Paterson, D. I. Sober, O. Pogorelko, C. Djalali, E. Munevar, D. P. Weygand, L. C. Smith, M. Kossov, L. C. Dennis, J. Zhang, B. E. Bonner, H. Avakian, Ji Li, M. Guillo, Brian Raue, S. Niccolai, I. Popa, S. Dhamija, N. Hassall, M. Bellis, H. Bagdasaryan, F. X. Girod, B. S. Ishkhanov, S. Park, R. Fatemi, N. Kalantarians, W. Gohn, A. V. Vlassov, J. R. Johnstone, D. Sharov, M. D. Mestayer, Y. G. Sharabian, Sylvain Bouchigny, J. Hardie, H. G. Juengst, J. Kuhn, L. El Fassi, C. Marchand, G. Audit, E. Wolin, H. Denizli, E. L. Isupov, R. De Vita, J. D. Kellie, L. Morand, Michael L. Williams, P. Rossi, N. Guler, William Brooks, Christian Weiss, A.V. Stavinsky, M. R. Niroula, R. W. Gothe, S. Boiarinov, W. Kim, M. Mirazita, W. J. Briscoe, L. Casey, G. Gavalian, C. Hanretty, S. Tkachenko, S. Anefalos Pereira, G. Niculescu, P. Nadel-Turonski, N. Benmouna, J. P. Ball, Tsutomu Mibe, Y. Prok, D. S. Carman, A. V. Skabelin, A. Cazes, Maryam Moteabbed, Hall Crannell, Bernhard Mecking, D. J. Tedeschi, M. Ripani, E. Pasyuk, V. Crede, Shifeng Chen, G. Rosner, K. V. Dharmawardane, J. R. Calarco, S. A. Dytman, I. Bedlinskiy, B. B. Niczyporuk, L. Guo, M. Ungaro, N. Pivnyuk, D. G. Crabb, R. A. Schumacher, M. Khandaker, S. Barrow, P. Mattione, M. S. Saini, P. Eugenio, M. Taiuti, K. Joo, G. S. Mutchler, Michael Vineyard, D. Cords, L. Graham, C. I O Gordon, A. Yegneswaran, M. Yurov, J. T. Goetz, S. Mehrabyan, S. Bültmann, V. Sapunenko, P. Collins, Dinko Pocanic, J. J. Melone, M. Osipenko, S. Procureur, T. A. Forest, C. Bookwalter, G. Riccardi, S. Stepanyan, S. E. Kuhn, Kalvir S. Dhuga, C. Butuceanu, J. Pierce, Avraham Klein, C. Tur, G. E. Dodge, L. Todor, H. Y. Lu, P. V. Degtyarenko, M. J. Amaryan, D. Protopopescu, M. MacCormick, I. Hleiqawi, S. Pozdniakov, I. Niculescu, D. Lawrence, S. L. Careccia, D. Schott, K. L. Giovanetti, Larry Weinstein, D. Doughty, D. Heddle, Y. Ilieva, B. Moreno, R. A. Miskimen, B. McKinnon, D. Branford, J. M. Laget, N. Gevorgyan, A. I. Ostrovidov, K. Park, D. G. Ireland, Volker D. Burkert, A. S. Biselli, Z. Krahn, N. Baillie, Laird Kramer, Gerard Gilfoyle, D. Sokhan, A. Fradi, N. Markov, G. Asryan, O. P. Dzyubak, R. A. Niyazov, P. Corvisiero, K. S. Egiyan, K. Mikhailov, P. Stoler, and K. Hicks
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Meson, 010308 nuclear & particles physics, Vector meson dominance, 01 natural sciences, Helicity, Gluon, 0103 physical sciences, Exponent, Vector meson, 010306 general physics, Nucleon, Exchange model
Abstract: Electroproduction of exclusive \ensuremath{\phi} vector mesons has been studied with the CLAS detector in the kinematic range $1.4\ensuremath{\leqslant}{Q}^{2}\ensuremath{\leqslant}3.8$ GeV${}^{2},0.0\ensuremath{\leqslant}{t}^{'}\ensuremath{\leqslant}3.6$ GeV${}^{2}$, and $2.0\ensuremath{\leqslant}W\ensuremath{\leqslant}3.0$ GeV. The scaling exponent for the total cross section as $1/({Q}^{2}+{M}_{\ensuremath{\phi}}^{2}){}^{n}$ was determined to be $n=2.49\ifmmode\pm\else\textpm\fi{}0.33$. The slope of the four-momentum transfer ${t}^{'}$ distribution is ${b}_{\ensuremath{\phi}}=0.98\ifmmode\pm\else\textpm\fi{}0.17$ GeV${}^{\ensuremath{-}2}$. Under the assumption of $s$-channel helicity conservation, we determine the ratio of longitudinal to transverse cross sections to be $R=0.86\ifmmode\pm\else\textpm\fi{}0.24$. A two-gluon exchange model is able to reproduce the main features of the data.
Published: 2008

34. Polarized structure functionσLT'forH1(e→,e'K+)Λin the nucleon resonance region

Author: L. C. Dennis, B. E. Bonner, S. McAleer, F. X. Girod, L. Blaszczyk, H. Avakian, D. Sharov, D. Lawrence, P. Stoler, K. Hicks, K. S. Egiyan, Laird Kramer, D. Doughty, L. C. Smith, E. Munevar, V. Mokeev, K. Mikhailov, Elton Smith, J. Langheinrich, S. S. Stepanyan, S. A. Philips, W. J. Briscoe, E. Pasyuk, B. S. Ishkhanov, D. P. Watts, S. A. Dytman, R. A. Schumacher, P. Eugenio, D. Heddle, H. Egiyan, J. W. Price, M. F. Vineyard, G. Asryan, O. P. Dzyubak, R. A. Niyazov, P. Nadel-Turonski, Tsutomu Mibe, H. G. Juengst, P. Corvisiero, E. Wolin, M. Taiuti, M. Anghinolfi, M. Kossov, James Mueller, E. De Sanctis, M. R. Niroula, J. P. Ball, M. Battaglieri, Y. Ilieva, P. D. Rubin, Y. G. Sharabian, A.V. Stavinsky, D. S. Carman, Patrick Girard, W. Kim, T. A. Forest, G. Niculescu, J. Lachniet, D. I. Sober, R. J. Feuerbach, Michael Wood, A. I. Ostrovidov, V. Sapunenko, L. Casey, Dinko Pocanic, R. Bradford, K. Lukashin, D. J. Tedeschi, K. Park, C. Hanretty, S. Stepanyan, K. Hafidi, D. G. Crabb, J. Pierce, V. S. Serov, S. E. Kuhn, Avraham Klein, E. Anciant, B. E. Stokes, B. B. Niczyporuk, I. Bedlinskiy, G. Ricco, D. G. Ireland, B. Moreno, G. E. Dodge, H. Y. Lu, P. V. Degtyarenko, N. Pivnyuk, Volker D. Burkert, A. S. Biselli, G. Audit, C. E. Hyde-Wright, R. Fatemi, A. V. Vlassov, R. De Vita, Z. W. Zhao, V. Kuznetsov, K. Joo, S. Procureur, Maryam Moteabbed, B. Zhao, D. G. Jenkins, Bernhard Mecking, Z. Krahn, Shifeng Chen, D. Sayre, S. Strauch, P. Collins, D. Protopopescu, I. Niculescu, M. Khandaker, S. Pozdniakov, Sylvain Bouchigny, J. J. Manak, P. Rossi, N. Baillie, S. Anefalos Pereira, A. Fradi, C. Cetina, A. Shafi, P. Dragovitsch, P. Mattione, Friedrich Klein, Kwangsoo Kim, R. A. Miskimen, B. McKinnon, V. P. Kubarovsky, G. Riccardi, J. Salamanca, Sergey Kuleshov, M. Osipenko, R. De Masi, Brian Raue, D. Branford, M. Mirazita, J. M. Laget, J. W C McNabb, S. A. Morrow, C. Djalali, G. S. Mutchler, M. Bektasoglu, S. Niccolai, F. Sabatié, N. Gevorgyan, C. Butuceanu, K. Beard, F. W. Hersman, N. A. Baltzell, J. T. Goetz, K. Livingston, D. S. Dale, N. Markov, O. Pogorelko, P. Coltharp, V. Crede, K. A. Griffioen, R. Dickson, J. Hardie, M. J. Amaryan, Kalvir S. Dhuga, P. Ambrozewicz, Gerard Gilfoyle, M. Nozar, D. Sokhan, M. MacCormick, M. Bellis, I. Hleiqawi, M. M. Ito, S. L. Careccia, J. Kuhn, R. W. Gothe, G. Gavalian, N. Guler, J. R. Calarco, G. A. Peterson, S. Simionatto, J. D. Kellie, S. Taylor, S. Tkachenko, K. Y. Kim, K. L. Giovanetti, B. Asavapibhop, J. P. Santoro, Roy Thompson, Larry Weinstein, S. Barrow, N. Benmouna, M. Ripani, M. Guidal, M. Guillo, L. Cheng, M. D. Mestayer, G. Rosner, R. Nasseripour, Nikolay Shvedunov, J. Hu, E. L. Isupov, L. Elouadrhiri, M. Holtrop, Michael L. Williams, S. Boiarinov, I. I. Strakovsky, B. M. Preedom, A. Deur, Lorenzo Zana, N. Kalantarians, H. Hakobyan, H. S. Jo, Gerald Feldman, Michael Dugger, W. K. Brooks, K. Wang, H. O. Funsten, C. Salgado, B. L. Berman, L. M. Qin, C. Paterson, Thierry Auger, M. Garçcon, J. R. Johnstone, V. Gyurjyan, J. Zhang, H. Bagdasaryan, L. Guo, M. Ungaro, A. Tkabladze, J. Yun, D. Cords, L. El Fassi, A. Yegneswaran, P. L. Cole, Y. Prok, Barry Ritchie, R. C. Minehart, Kei Moriya, C. A. Meyer, G. V. Fedotov, D. P. Weygand, A. V. Skabelin, and N. Dashyan
Subjects: Physics, Nuclear and High Energy Physics, Angular range, 010308 nuclear & particles physics, Hydrogen-1, Structure function, Hyperon, Sigma, Resonance, Lambda, 01 natural sciences, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: The first measurements of the polarized structure function {sigma}{sub LT{sup '}} for the reaction {sup 1}H(e-vector,e{sup '}K{sup +}){lambda} in the nucleon resonance region are reported. Measurements are included from threshold up to W=2.05 GeV for central values of Q{sup 2} of 0.65 and 1.00 GeV{sup 2}, and nearly the entire kaon center-of-mass angular range. {sigma}{sub LT{sup '}} is the imaginary part of the longitudinal-transverse response and is expected to be sensitive to interferences between competing intermediate s-channel resonances, as well as resonant and nonresonant processes. The results for {sigma}{sub LT{sup '}} are comparable in magnitude to previously reported results from CLAS for {sigma}{sub LT}, the real part of the same response. An intriguing sign change in {sigma}{sub LT{sup '}} is observed in the high Q{sup 2} data at W{approx_equal}1.9 GeV. Comparisons to several existing model predictions are shown.
Published: 2008

35. Measurement ofep→epπ0beam spin asymmetries above the resonance region

Author: R. De Masi, M. Garçon, B. Zhao, M. J. Amaryan, P. Ambrozewicz, M. Anghinolfi, G. Asryan, H. Avakian, H. Bagdasaryan, N. Baillie, J. Ball, J. P. Ball, N. A. Baltzell, V. Batourine, M. Battaglieri, I. Bedlinskiy, M. Bellis, N. Benmouna, B. L. Berman, P. Bertin, A. S. Biselli, L. Blaszczyk, S. Bouchigny, S. Boiarinov, R. Bradford, D. Branford, W. J. Briscoe, W. K. Brooks, S. Bültmann, V. D. Burkert, C. Butuceanu, J. R. Calarco, S. L. Careccia, D. S. Carman, L. Casey, S. Chen, L. Cheng, P. L. Cole, P. Collins, P. Coltharp, D. Crabb, V. Crede, N. Dashyan, E. De Sanctis, R. De Vita, P. V. Degtyarenko, A. Deur, K. V. Dharmawardane, R. Dickson, C. Djalali, G. E. Dodge, J. Donnelly, D. Doughty, M. Dugger, O. P. Dzyubak, H. Egiyan, K. S. Egiyan, L. El Fassi, L. Elouadrhiri, P. Eugenio, G. Fedotov, G. Feldman, A. Fradi, H. Funsten, G. Gavalian, G. P. Gilfoyle, K. L. Giovanetti, F. X. Girod, J. T. Goetz, A. Gonenc, R. W. Gothe, K. A. Griffioen, M. Guidal, N. Guler, L. Guo, V. Gyurjyan, K. Hafidi, H. Hakobyan, C. Hanretty, F. W. Hersman, K. Hicks, I. Hleiqawi, M. Holtrop, C. E. Hyde-Wright, Y. Ilieva, D. G. Ireland, B. S. Ishkhanov, E. L. Isupov, M. M. Ito, D. Jenkins, H. S. Jo, J. R. Johnstone, K. Joo, H. G. Juengst, N. Kalantarians, J. D. Kellie, M. Khandaker, W. Kim, A. Klein, F. J. Klein, A. V. Klimenko, M. Kossov, Z. Krahn, L. H. Kramer, V. Kubarovsky, J. Kuhn, S. E. Kuhn, S. V. Kuleshov, J. Lachniet, J. M. Laget, J. Langheinrich, D. Lawrence, T. Lee, K. Livingston, H. Y. Lu, M. MacCormick, N. Markov, P. Mattione, M. Mazouz, B. McKinnon, B. A. Mecking, M. D. Mestayer, C. A. Meyer, T. Mibe, B. Michel, K. Mikhailov, M. Mirazita, R. Miskimen, V. Mokeev, B. Moreno, K. Moriya, S. A. Morrow, M. Moteabbed, E. Munevar, G. S. Mutchler, P. Nadel-Turonski, R. Nasseripour, S. Niccolai, G. Niculescu, I. Niculescu, B. B. Niczyporuk, M. R. Niroula, R. A. Niyazov, M. Nozar, M. Osipenko, A. I. Ostrovidov, K. Park, E. Pasyuk, C. Paterson, S. Anefalos Pereira, J. Pierce, N. Pivnyuk, D. Pocanic, O. Pogorelko, S. Pozdniakov, J. W. Price, S. Procureur, Y. Prok, D. Protopopescu, B. A. Raue, G. Ricco, M. Ripani, B. G. Ritchie, F. Ronchetti, G. Rosner, P. Rossi, F. Sabatié, J. Salamanca, C. Salgado, J. P. Santoro, V. Sapunenko, R. A. Schumacher, V. S. Serov, Y. G. Sharabian, D. Sharov, N. V. Shvedunov, E. S. Smith, L. C. Smith, D. I. Sober, D. Sokhan, A. Stavinsky, S. Stepanyan, S. S. Stepanyan, B. E. Stokes, P. Stoler, I. I. Strakovsky, S. Strauch, M. Taiuti, D. J. Tedeschi, A. Tkabladze, S. Tkachenko, C. Tur, M. Ungaro, M. F. Vineyard, A. V. Vlassov, E. Voutier, D. P. Watts, L. B. Weinstein, D. P. Weygand, M. Williams, E. Wolin, M. H. Wood, A. Yegneswaran, L. Zana, J. Zhang, and Z. W. Zhao
Subjects: Physics, Nuclear and High Energy Physics, Photon, Spectrometer, 010308 nuclear & particles physics, media_common.quotation_subject, Parton, 01 natural sciences, Asymmetry, Nuclear physics, Formalism (philosophy of mathematics), Amplitude, 0103 physical sciences, Cathode ray, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, media_common
Abstract: The beam spin asymmetry (BSA) in the exclusive reaction ep->ep pi0 was measured with the CEBAF 5.77 GeV polarized electron beam and Large Acceptance Spectrometer(CLAS). The xB, Q2, t and phi dependences of the pi0 BSA are presented in the deep inelastic regime. The asymmetries are fitted with a sin(phi) function and their amplitudes are extracted. Overall, they are of the order of 0.04 - 0.11 and roughly independent of t. This is the signature of a non-zero longitudinal-transverse interference. The implications concerning the applicability of a formalism based on generalized parton distributions, as well as the extension of a Regge formalism at high photon virtualities, are discussed.
Published: 2008

36. Light Vector Mesons in the Nuclear Medium

Author: V. Crede, S. McAleer, L. Blaszczyk, J. R. Calarco, B. L. Berman, E. De Sanctis, S. Tkachenko, M. Taiuti, R. A. Schumacher, Michael Wood, A. I. Ostrovidov, G. Asryan, C. I O Gordon, K. Hafidi, K. Park, C. Paterson, J. W. Price, O. P. Dzyubak, R. A. Niyazov, V. S. Serov, L. C. Dennis, D. G. Ireland, B. G. Ritchie, B. E. Stokes, J. Kuhn, M. R. Niroula, Cynthia Marie Hadjidakis, M. J. Amaryan, H. Avakian, M. MacCormick, I. Hleiqawi, Volker D. Burkert, G. S. Adams, S. L. Careccia, A. S. Biselli, S. Stepanyan, D. Sharov, A. V. Vlassov, Philip L. Cole, Larry Weinstein, J. Pierce, Avraham Klein, Chaden Djalali, K.H. Hicks, D. J. Tedeschi, K. Joo, Sylvain Bouchigny, G. S. Mutchler, Michael Dugger, W. Kim, Gerard Gilfoyle, D. Sokhan, H. S. Jo, K. S. Egiyan, J. Hardie, Friedrich Klein, J. P. Cummings, Laird Kramer, K. Livingston, S. A. Dytman, W. K. Brooks, B. Carnahan, S. Niccolai, H. O. Funsten, P. Collins, Ulrich Mosel, Z. W. Zhao, I. Bedlinskiy, H. G. Juengst, G. Niculescu, R. Nasseripour, K. Mikhailov, R. A. Miskimen, B. McKinnon, H. Hakobyan, S. Anefalos Pereira, D. G. Jenkins, P. Coltharp, Hall Crannell, A.V. Stavinsky, P. Eugenio, R. W. Gothe, V. Sapunenko, M. Bektasoglu, C. Salgado, Dinko Pocanic, M. M. Ito, D. Branford, V. Gyurjyan, P. Khetarpal, A. Fradi, M. Holtrop, M. Kossov, J. M. Laget, D. P. Weygand, Y. Ilieva, V. P. Kubarovsky, R. De Vita, L. C. Smith, E. Munevar, G. E. Dodge, B. S. Ishkhanov, P. Nadel-Turonski, H. Bagdasaryan, P. V. Degtyarenko, N. Guler, S. E. Kuhn, Federico Ronchetti, J. J. Melone, K. Moriya, C. Hanretty, I. Niculescu, D. Lawrence, J. D. Kellie, Victor Mokeev, J. R. Johnstone, L. Guo, M. Ungaro, Latifa Elouadrhiri, G. Rosner, J. Lachniet, A. Tkabladze, M. Guidal, A. Yegneswaran, R. C. Minehart, S. Barrow, C. Tur, P. Rossi, J. Langheinrich, S. S. Stepanyan, E. Pasyuk, J. Zhang, C. A. Meyer, S. Mehrabyan, F. X. Girod, Baile Zhang, G. V. Fedotov, G. Gavalian, R. S. Hakobyan, R. Dickson, M. Ripani, L. El Fassi, D. Doughty, Z. Krahn, N. Benmouna, G. Riccardi, B. A. Raue, M. Osipenko, C. Butuceanu, Tsutomu Mibe, L. Cheng, Shifeng Chen, N. Baillie, Daniel S. Carman, F. Sabatié, Nikolay Shvedunov, K. L. Giovanetti, S. V. Kuleshov, D. Protopopescu, G. Ricco, S. Pozdniakov, M. Garçon, E. Wolin, C. E. Hyde-Wright, O. Pogorelko, J. Ball, N. Kalantarians, M. Khandaker, D. G. Crabb, M. Nozar, B. Zhao, H. Denizli, H. Y. Lu, J. T. Goetz, F. W. Hersman, M. Mirazita, Elton Smith, N. Dashyan, James Mueller, Alexei V. Klimenko, Y. Prok, I. I. Strakovsky, Y. G. Sharabian, P. Muehlich, A. Deur, Ji Li, M. D. Mestayer, R. J. Feuerbach, E. L. Isupov, Michael L. Williams, Maryam Moteabbed, Bernhard Mecking, K. V. Dharmawardane, S. Boiarinov, B. M. Preedom, Lorenzo Zana, J. P. Santoro, M. Battaglieri, D. P. Watts, H. Egiyan, Gerald Feldman, N. A. Baltzell, N. Markov, R. Bradford, K. A. Griffioen, N. Hassall, M. Bellis, J. Salamanca, P. Mattione, J. W C McNabb, M. Anghinolfi, L. Casey, B. B. Niczyporuk, Michael Vineyard, N. Pivnyuk, W. J. Briscoe, L. Todor, S. A. Morrow, S. Strauch, P. Ambrozewicz, P. Stoler, D. I. Sober, Thomas Jefferson National Accelerator Facility (Jefferson Lab), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, CLAS, and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Nuclear and High Energy Physics, Particle physics, Rho meson, Meson, Nuclear Theory, FOS: Physical sciences, light vector mesons, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, chiral symmetry, Spectral line, Nuclear physics, ENHANCEMENT, CLAS, 0103 physical sciences, 11.30.Rd, 14.40.Cs, 24.85.+p, QCD SUM-RULES, Invariant mass, RHO-MESON, Nuclear Experiment (nucl-ex), 010306 general physics, in-medium modifications, Nuclear Experiment, Physics, AU COLLISIONS, QCD sum rules, CEBAF, 010308 nuclear & particles physics, QCD SUM-RULES, RHO-MESON, SPECTRAL-FUNCTION, AU COLLISIONS, OMEGA-MESONS, MATTER, CLAS, ENHANCEMENT, SYSTEM, CEBAF, Nuclear matter, SPECTRAL-FUNCTION, Deuterium, Mass spectrum, High Energy Physics::Experiment, MATTER, SYSTEM, OMEGA-MESONS
Abstract: The light vector mesons ($\rho$, $\omega$, and $\phi$) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the $\rho$ meson at normal nuclear densities and zero temperature. The vector mesons were detected with the CEBAF Large Acceptance Spectrometer (CLAS) via their decays to $e^{+}e^{-}$. The rare leptonic decay was chosen to reduce final-state interactions. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing technique. The $\rho$ meson mass spectrum was extracted after the $\omega$ and $\phi$ signals were removed in a nearly model-independent way. Comparisons were made between the $\rho$ mass spectra from the heavy targets ($A > 2$) with the mass spectrum extracted from the deuterium target. With respect to the $\rho$-meson mass, we obtain a small shift compatible with zero. Also, we measure widths consistent with standard nuclear many-body effects such as collisional broadening and Fermi motion., Comment: 15 pages, 18 figures, 3 tables
Published: 2008

37. Bayesian analysis of pentaquark signals from CLAS data

Author: W. Kim, P. Coltharp, L. C. Smith, E. Munevar, G. Niculescu, B. S. Ishkhanov, M. R. Niroula, E. Wolin, D. P. Watts, A. V. Vlassov, Lorenzo Zana, N. Markov, Gerard Gilfoyle, H. Avakian, D. Sharov, R. De Vita, A. Fradi, F. X. Girod, L. Blaszczyk, D. Sokhan, H. Hakobyan, H. S. Jo, Gerald Feldman, D. Doughty, Chaden Djalali, J. Kuhn, Michael Dugger, B. Zhao, W. J. Briscoe, G. E. Dodge, H. Y. Lu, S. Anefalos Pereira, Federico Ronchetti, M. Kossov, H. O. Funsten, J. P. Ball, Y. Prok, E. Pasyuk, B. E. Stokes, J. P. Santoro, D. S. Carman, C. Salgado, B. L. Berman, C. E. Hyde-Wright, Atilla Gonenc, P. V. Degtyarenko, Sylvain Bouchigny, K. Joo, Y. Ilieva, N. Hassall, M. Bellis, G. Ricco, J. W. Price, E. De Sanctis, P. Rossi, Laird Kramer, V. Kuznetsov, J. Lachniet, D. I. Sober, Z. Krahn, D. G. Crabb, F. W. Hersman, Sergey Kuleshov, Friedrich Klein, Brian Raue, N. Dashyan, Michael Wood, M. Nozar, M. Ripani, M. D. Mestayer, P. Eugenio, N. Baillie, K. Hafidi, M. Taiuti, Z. W. Zhao, C. Paterson, I. Niculescu, E. L. Isupov, V. Crede, R. A. Miskimen, B. McKinnon, D. G. Jenkins, Michael L. Williams, J. Langheinrich, A. I. Ostrovidov, D. Lawrence, M. Osipenko, V. S. Serov, N. A. Baltzell, S. S. Stepanyan, D. G. Ireland, S. Boiarinov, D. Branford, J. D. Kellie, J. R. Calarco, K. A. Griffioen, Volker D. Burkert, A. S. Biselli, P. Collins, M. Mirazita, V. Batourine, M. Khandaker, G. Rosner, R. Nasseripour, G. Gavalian, J. M. Laget, J. Donnelly, S. Tkachenko, N. Gevorgyan, R. De Masi, K. Park, F. Sabatié, G. Asryan, N. Benmouna, S. Procureur, Maryam Moteabbed, Bernhard Mecking, Michael Vineyard, B. Moreno, R. A. Schumacher, R. W. Gothe, L. Cheng, O. P. Dzyubak, C. Butuceanu, Nikolay Shvedunov, S. Strauch, M. Guidal, M. MacCormick, D. Protopopescu, I. Hleiqawi, M. Battaglieri, S. L. Careccia, G. S. Mutchler, S. Pozdniakov, M. Garçon, R. Bradford, K. L. Giovanetti, N. Kalantarians, Larry Weinstein, K. Livingston, M. Holtrop, S. Niccolai, R. Dickson, N. Guler, S. Stepanyan, H. G. Juengst, J. Pierce, Avraham Klein, A.V. Stavinsky, K. S. Egiyan, D. J. Tedeschi, V. Gyurjyan, I. Bedlinskiy, K. Mikhailov, J. Zhang, H. Bagdasaryan, L. Guo, M. Ungaro, P. Stoler, R. A. Niyazov, A. Yegneswaran, P. Nadel-Turonski, Tsutomu Mibe, C. Hanretty, Barry Ritchie, Victor Mokeev, J. R. Johnstone, P. L. Cole, A. Tkabladze, Latifa Elouadrhiri, L. El Fassi, Kei Moriya, C. A. Meyer, V. Sapunenko, G. V. Fedotov, S. A. Morrow, P. Ambrozewicz, D. P. Weygand, J. Salamanca, L. Casey, W. Gohn, C. Tur, B. B. Niczyporuk, N. Pivnyuk, A. Deur, W. K. Brooks, M. Anghinolfi, Y. G. Sharabian, Shifeng Chen, P. Mattione, J. T. Goetz, V. P. Kubarovsky, O. Pogorelko, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, CLAS, and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)
Subjects: Quark, Particle physics, Bayesian probability, FOS: Physical sciences, General Physics and Astronomy, Physics and Astronomy(all), 01 natural sciences, Bayesian, Particle identification, High Energy Physics - Phenomenology (hep-ph), CLAS, 0103 physical sciences, Feature (machine learning), Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, pentaquark, Physics, 010308 nuclear & particles physics, Hyperon, Probability and statistics, Fermion, 13.60.Rj, 12.39.Mk, 14.20.Jn, 14.80.-j, 02.50.-r, 02.70.Uu, Pentaquark, High Energy Physics - Phenomenology, Physics - Data Analysis, Statistics and Probability, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Data Analysis, Statistics and Probability (physics.data-an)
Abstract: We examine the results of two measurements by the CLAS collaboration, one of which claimed evidence for a $\Theta^{+}$ pentaquark, whilst the other found no such evidence. The unique feature of these two experiments was that they were performed with the same experimental setup. Using a Bayesian analysis we find that the results of the two experiments are in fact compatible with each other, but that the first measurement did not contain sufficient information to determine unambiguously the existence of a $\Theta^{+}$. Further, we suggest a means by which the existence of a new candidate particle can be tested in a rigorous manner., Comment: 5 pages, 3 figures
Published: 2008

38. Cross sections and beam asymmetries fore→p→enπ+in the nucleon resonance region for1.7⩽Q2⩽4.5GeV2

Author: R. Fatemi, A. V. Vlassov, T. Lee, H. G. Juengst, A. Fradi, R. De Vita, A.V. Stavinsky, N. Markov, N. Hassall, B. Zhao, D. J. Tedeschi, S. Park, Sylvain Bouchigny, K. Hafnaoui, K. Livingston, D. S. Dale, G. Rosner, R. Nasseripour, I. Bedlinskiy, S. Anefalos Pereira, P. Rossi, E. Wolin, R. Dickson, Ji Li, J. P. Ball, Y. Prok, F. W. Hersman, V. Kuznetsov, J. P. Cummings, V. Sapunenko, Dinko Pocanic, C. Hanretty, N. Guler, S. McAleer, F. X. Girod, L. Blaszczyk, D. G. Ireland, V. Crede, S. E. Kuhn, M. Osipenko, F. Sabatié, J. Lachniet, H. Denizli, A. Tkabladze, J. R. Johnstone, M. Kossov, J. R. Calarco, D. G. Crabb, D. Rowntree, J. Donnelly, G. Asryan, O. P. Dzyubak, R. A. Niyazov, A. I. Ostrovidov, A. C S Lima, R. Suleiman, I. Popa, G. S. Mutchler, L. Guo, G. E. Dodge, H. Y. Lu, M. Ungaro, D. Doughty, M. D. Mestayer, S. Niccolai, E. De Sanctis, Volker D. Burkert, A. S. Biselli, E. L. Isupov, C. Tur, M. Guillo, D. Heddle, W. Gohn, M. Guidal, J. Hardie, Z. Krahn, J. Kuhn, P. L. Cole, S. Barrow, Elton Smith, Friedrich Klein, M. Yurov, Kalvir S. Dhuga, Michael L. Williams, P. V. Degtyarenko, N. Baillie, M. Anghinolfi, James Mueller, A. V. Skabelin, L. Todor, D. Protopopescu, S. Mehrabyan, D. I. Sober, S. Pozdniakov, M. Garçon, J. Yun, D. Cords, S. S. Stepanyan, S. Boiarinov, P. D. Rubin, Y. G. Sharabian, A. Yegneswaran, R. A. Miskimen, Brian Raue, B. McKinnon, Atilla Gonenc, R. C. Minehart, Kei Moriya, C. A. Meyer, J. W. Price, T. Takeuchi, M. Holtrop, I. Niculescu, C. Bookwalter, G. V. Fedotov, W. Kim, G. Niculescu, G. Gavalian, Laird Kramer, G. Riccardi, D. Lawrence, Baile Zhang, Shifeng Chen, S. Dhamija, J. Shaw, P. Corvisiero, S. Tkachenko, L. El Fassi, D. Branford, Michael Wood, R. De Masi, B. E. Stokes, K. Hafidi, C. Butuceanu, D. Keller, D. Schott, G. S. Adams, N. A. Baltzell, V. Gyurjyan, N. Benmouna, M. Ripani, K. Joo, N. Dashyan, P. Mattione, D. P. Weygand, M. S. Saini, M. Mirazita, J. M. Laget, V. S. Serov, R. W. Gothe, Y. Ilieva, N. Gevorgyan, Michael Vineyard, J. Zhang, P. Nadel-Turonski, Alexei V. Klimenko, L. Cheng, Tsutomu Mibe, B. M. Preedom, L. Elouadrhiri, J. Langheinrich, K. Y. Kim, Nikolay Shvedunov, J. T. Goetz, E. Polli, H. Bagdasaryan, Lorenzo Zana, J. P. Santoro, Barry Ritchie, S. A. Philips, M. Khandaker, P. Eugenio, M. Taiuti, G. V. O'Rielly, Z. W. Zhao, I. I. Strakovsky, P. Stoler, J. D. Kellie, S. A. Morrow, V. P. Kubarovsky, V. Mokeev, R. A. Schumacher, B. Moreno, Gerard Gilfoyle, G. Ricco, C. Djalali, H. Hakobyan, H. S. Jo, Gerald Feldman, K. Hicks, O. Pogorelko, A. Deur, D. G. Jenkins, Federico Ronchetti, L. C. Dennis, L. Graham, P. Collins, B. E. Bonner, J. J. Melone, C. Salgado, D. Sokhan, K. Park, Daniel S. Carman, M. J. Amaryan, K. S. Egiyan, C. I O Gordon, N. Kalantarians, H. Avakian, W. K. Brooks, M. MacCormick, I. Hleiqawi, C. E. Hyde-Wright, D. Sharov, P. Ambrozewicz, K. Mikhailov, S. Bültmann, L. Morand, T. A. Forest, Cynthia Marie Hadjidakis, S. L. Careccia, Sergey Kuleshov, S. Stepanyan, K. L. Giovanetti, J. Pierce, Avraham Klein, Larry Weinstein, M. Bektasoglu, M. Nozar, Michael Dugger, H. O. Funsten, W. J. Briscoe, E. Pasyuk, S. A. Dytman, J. Salamanca, J. W C McNabb, L. Casey, B. B. Niczyporuk, N. Pivnyuk, V. Batourine, M. Battaglieri, L. C. Smith, E. Munevar, B. S. Ishkhanov, B. L. Berman, R. Bradford, B. A. Mecking, K. Lukashin, L. M. Qin, R. S. Hakobyan, K. A. Griffioen, C. Paterson, M. Klusman, D. P. Watts, M. R. Niroula, E. Golovatch, M. Bellis, S. Strauch, H. Egiyan, A. Cazes, Maryam Moteabbed, P. Coltharp, K. V. Dharmawardane, M. Y. Gabrielyan, R. J. Feuerbach, M. M. Ito, and Inna Aznauryan
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Meson, 010308 nuclear & particles physics, Resonance, 01 natural sciences, Excited state, Isospin, 0103 physical sciences, Production (computer science), Invariant mass, Sensitivity (control systems), Atomic physics, 010306 general physics, Nucleon
Abstract: The exclusive electroproduction process $\stackrel{\ensuremath{\rightarrow}}{e}p\ensuremath{\rightarrow}{e}^{'}n{\ensuremath{\pi}}^{+}$ was measured in the range of the photon virtuality ${Q}^{2}=1.7\text{\ensuremath{-}}4.5 {\mathrm{GeV}}^{2}$, and the invariant mass range for the $n{\ensuremath{\pi}}^{+}$ system of $W=1.15\text{\ensuremath{-}}1.7 \mathrm{GeV}$ using the CEBAF Large Acceptance Spectrometer. For the first time, these kinematics are probed in exclusive ${\ensuremath{\pi}}^{+}$ production from protons with nearly full coverage in the azimuthal and polar angles of the $n{\ensuremath{\pi}}^{+}$ center-of-mass system. The $n{\ensuremath{\pi}}^{+}$ channel has particular sensitivity to the isospin \textonehalf{} excited nucleon states, and together with the $p{\ensuremath{\pi}}^{0}$ final state will serve to determine the transition form factors of a large number of resonances. The largest discrepancy between these results and present modes was seen in the ${\ensuremath{\sigma}}_{{\mathit{LT}}^{'}}$ structure function. In this experiment, 31,295 cross section and 4,184 asymmetry data points were measured. Because of the large volume of data, only a reduced set of structure functions and Legendre polynomial moments can be presented that are obtained in model-independent fits to the differential cross sections.
Published: 2008

39. Measurement of Deeply Virtual Compton Scattering Beam-Spin Asymmetries

Author: G. Niculescu, Gerard Gilfoyle, K. Livingston, L. Blaszczyk, S. Tkachenko, I. I. Strakovsky, A. Deur, D. Sokhan, J. Donnelly, G. Asryan, O. P. Dzyubak, A. V. Vlassov, M. Taiuti, K. S. Egiyan, K. Mikhailov, T. Lee, Atilla Gonenc, G. E. Dodge, R. W. Gothe, J. W. Price, M. Guidal, P. Rossi, R. Dickson, V. Crede, D. Doughty, P. V. Degtyarenko, Daniel S. Carman, Alexei V. Klimenko, J. R. Calarco, M. Mazouz, R. Miskimen, J. Salamanca, Lorenzo Zana, J. Kuhn, M. Ripani, Philip L. Cole, J. P. Santoro, Y. Prok, Z. Krahn, Hovanes Egiyan, B. A. Raue, D. P. Watts, Barry Ritchie, O. Pogorelko, M. Khandaker, V. Batourine, C. Butuceanu, G. Ricco, I. Niculescu, R. A. Niyazov, H. Y. Lu, Friedrich Klein, D. Lawrence, E. Wolin, Z. W. Zhao, N. Markov, Elton Smith, Gerald Feldman, B. McKinnon, J. Ball, S. A. Morrow, N. Baillie, R. De Masi, J. P. Ball, M. Nozar, P. Eugenio, B. Zhao, D. Protopopescu, C. E. Hyde, S. Pozdniakov, M. Garçon, D. Branford, P. Stoler, Michael Wood, R. A. Schumacher, E. De Sanctis, M. J. Amaryan, J. M. Laget, K. Hafidi, P. Ambrozewicz, M. MacCormick, Y. Ilieva, B. Michel, V. S. Serov, D. G. Crabb, J. Langheinrich, E. Voutier, S. S. Stepanyan, E. Pasyuk, R. De Vita, I. Hleiqawi, M. Osipenko, M. Kossov, S. L. Careccia, B. E. Stokes, N. Guler, Sylvain Bouchigny, S. Bültmann, Tsutomu Mibe, M. Anghinolfi, M. R. Niroula, N. Dashyan, F. W. Hersman, L. C. Smith, E. Munevar, S. Stepanyan, L. Casey, K.H. Hicks, K. Joo, Y. G. Sharabian, Larry Weinstein, J. Pierce, Avraham Klein, Latifa Elouadrhiri, D. J. Tedeschi, B. L. Berman, B. S. Ishkhanov, I. Bedlinskiy, N. A. Baltzell, C. A. Meyer, V. P. Kubarovsky, G. V. Fedotov, Laird Kramer, P. Collins, David Jenkins, J. D. Kellie, B. B. Niczyporuk, K. L. Giovanetti, S. V. Kuleshov, C. Hanretty, M. Holtrop, C. Paterson, V. Sapunenko, Michael Vineyard, H. Avakian, D. Sharov, N. Pivnyuk, Dinko Pocanic, D. P. Weygand, W. J. Briscoe, H. S. Jo, K. A. Griffioen, A. I. Ostrovidov, K. Park, D. G. Ireland, S. E. Kuhn, M. D. Mestayer, Volker D. Burkert, A. S. Biselli, S. Niccolai, E. L. Isupov, Michael L. Williams, W. K. Brooks, S. Boiarinov, C. Tur, G. Rosner, P. Coltharp, Victor Mokeev, J. R. Johnstone, Shifeng Chen, J. Lachniet, M. M. Ito, L. Guo, P. Mattione, A. Tkabladze, J. T. Goetz, V. Gyurjyan, M. Mirazita, M. Ungaro, J. Zhang, F. X. Girod, S. Strauch, L. El Fassi, R. Nasseripour, P. Nadel-Turonski, D. I. Sober, G. S. Mutchler, H. Bagdasaryan, M. Bellis, S. Procureur, Maryam Moteabbed, Bernhard Mecking, K. V. Dharmawardane, G. Gavalian, M. Battaglieri, N. Benmouna, R. Bradford, Chaden Djalali, Michael Dugger, H. O. Funsten, K. Moriya, Carlos A. Salgado, L. Cheng, F. Sabatié, Nikolay Shvedunov, A. Yegneswaran, N. Kalantarians, H. G. Juengst, H. Hakobyan, S. Anefalos Pereira, A.V. Stavinsky, W. Kim, Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), CLAS, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)
Subjects: Quark, Particle physics, Photon, Proton, media_common.quotation_subject, HERA, General Physics and Astronomy, Parton, Kinematics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Asymmetry, Nuclear physics, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], PARTON DISTRIBUTIONS, NUCLEON, HERA, NUCLEON, 010306 general physics, Nuclear Experiment, media_common, Physics, 010308 nuclear & particles physics, Compton scattering, 12.40.Vv,13.40.Gp,13.60.Fz,13.60.Hb,13.60.-r,14.20.Dh,24.85.+p, PARTON DISTRIBUTIONS, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], High Energy Physics::Experiment, Nucleon
Abstract: 1 tex file (6 pages), 4 (eps) figures; The beam spin asymmetries in the hard exclusive electroproduction of photons on the proton (ep -> epg) were measured over a wide kinematic range and with high statistical accuracy. These asymmetries result from the interference of the Bethe-Heitler process and of deeply virtual Compton scattering. Over the whole kinematic range (x_B from 0.11 to 0.58, Q^2 from 1 to 4.8 GeV^2, -t from 0.09 to 1.8 GeV^2), the azimuthal dependence of the asymmetries is compatible with expectations from leading-twist dominance, A = a*sin(phi)/[1+c*cos(phi)]. This extensive set of data can thus be used to constrain significantly the generalized parton distributions of the nucleon in the valence quark sector.
Published: 2008

40. Search for Medium Modifications of theρMeson

Author: S. A. Morrow, C. Djalali, C. Hanretty, A.V. Stavinsky, P. Ambrozewicz, D. J. Tedeschi, Baile Zhang, M. J. Amaryan, H. Juengst, R. A. Miskimen, B. McKinnon, M. MacCormick, Shifeng Chen, I. Bedlinskiy, Carlos A. Salgado, I. Hleiqawi, Andreas Klein, Ji Li, S. L. Careccia, D. Branford, L. Casey, B. B. Niczyporuk, N. Pivnyuk, Nikolay Shvedunov, M. Mirazita, J. M. Laget, K. L. Giovanetti, P. Collins, E. L. Isupov, N. Markov, J. Salamanca, Mark Richard James Williams, J. W C McNabb, Larry Weinstein, J. T. Goetz, S. Boiarinov, K. A. Griffioen, B. M. Preedom, S. McAleer, C. E. Hyde-Wright, J. P. Cummings, S. Niccolai, L. Elouadrhiri, S. Mehrabyan, H. Denizli, F. X. Girod, L. Blaszczyk, R. J. Feuerbach, Lorenzo Zana, J. Hardie, E. De Sanctis, Jens H. Kuhn, I. I. Strakovsky, A. I. Ostrovidov, K. Park, R. A. Schumacher, N. A. Baltzell, M. Khandaker, Dinko Pocanic, D. G. Ireland, V. Crede, Sergey Kuleshov, J. P. Santoro, M. Bektasoglu, H. Hakobyan, Federico Ronchetti, H. S. Jo, G. Riccardi, P. Muehlich, A. Deur, M. Kossov, Gerald Feldman, Volker D. Burkert, A. S. Biselli, S. E. Kuhn, J. R. Calarco, M. Guidal, Z. Krahn, L. C. Smith, E. Munevar, G. Ricco, D. I. Sober, S. Strauch, Rakhsha Nasseripour, K. Moriya, L. Todor, D. Doughty, C. Butuceanu, D. Protopopescu, N. Dashyan, G. Niculescu, M. Holtrop, N. Baillie, Mestayer, M. Battaglieri, B. S. Ishkhanov, S. Pozdniakov, M. Garçon, P. Eugenio, D. P. Watts, H. Egiyan, M. Taiuti, J. D. Kellie, R. C. Minehart, C. A. Meyer, B. Carnahan, S. Tkachenko, C. I O Gordon, F. Sabatié, V. Sapunenko, Laird Kramer, R. Bradford, B. A. Mecking, A. V. Vlassov, J. Langheinrich, G. V. Fedotov, N. Kalantarians, N. Benmouna, M. Ripani, M. Nozar, Yordanka Ilieva, Michael Vineyard, R. De Vita, Gerard Gilfoyle, M. Anghinolfi, Ulrich Mosel, J. J. Melone, Brian Raue, K. Livingston, James Mueller, D. P. Weygand, D. Sokhan, Cynthia Marie Hadjidakis, E. S. Smith, Maryam Moteabbed, M. R. Niroula, Alexei V. Klimenko, S. Anefalos Pereira, D. G. Jenkins, G. S. Mutchler, Michael Dugger, H. O. Funsten, Y. G. Sharabian, K. V. Dharmawardane, E. Wolin, B. L. Berman, S. Stepanyan, L. C. Dennis, R. Dickson, Sylvain Bouchigny, Barry Ritchie, J. P. Ball, Y. Prok, D. S. Carman, P. Rossi, C. Paterson, D. G. Crabb, J. Pierce, H. Avakian, P. Mattione, D. Sharov, N. Guler, G. E. Dodge, H. Y. Lu, P. V. Degtyarenko, S. Barrow, I. Niculescu, D. Lawrence, R. De Masi, P. Coltharp, William Brooks, Hall Crannell, M. M. Ito, S. Bültmann, W. J. Briscoe, E. Pasyuk, J. R. Johnstone, L. Guo, M. Ungaro, S. A. Dytman, M. Bellis, K. Joo, S. S. Stepanyan, A. Yegneswaran, V. Gyurjyan, J. Zhang, H. Bagdasaryan, J. W. Price, V. P. Kubarovsky, G. Rosner, O. Pogorelko, Frank Klein, Michael Wood, K. Hafidi, K. S. Egiyan, V. S. Serov, B. E. Stokes, G. S. Adams, K. Mikhailov, Clarisse Tur, P. Nadel-Turonski, Tsutomu Mibe, G. Gavalian, V. Mokeev, P. Stoler, W. Kim, J. Lachniet, K. Hicks, A. Tkabladze, R. S. Hakobyan, L. El Fassi, M. Osipenko, G. Asryan, O. P. Dzyubak, R. A. Niyazov, P. L. Cole, Z. W. Zhao, B. Zhao, F. W. Hersman, and R. W. Gothe
Subjects: Physics, Particle physics, Rho meson, Meson, Spectrometer, Nuclear Theory, Spectrum (functional analysis), General Physics and Astronomy, Order (ring theory), Physics and Astronomy(all), Resonance (particle physics), medicine.anatomical_structure, Deuterium, medicine, High Energy Physics::Experiment, Nuclear Experiment, Nucleus
Abstract: The photoproduction of vector mesons on various nuclei has been studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory. The vector mesons, $$\rho$$, $$\omega$$, and $$\phi$$, are observed via their decay to $e^+e^-$, in order to reduce the effects of final state interactions in the nucleus. Of particular interest are possible in-medium effects on the properties of the $$\rho$$ meson. The $$\rho$$ spectral function is extracted from the data on various nuclei, carbon, iron, and titanium, and compared to the spectrum from liquid deuterium, which is relatively free of nuclear effects. We observe no significant mass shift for the $$\rho$$ meson; however, there is some widening of the resonance in titanium and iron, which is consistent with expected collisional broadening.
Published: 2007

41. Erratum: Cross sections for theγp→K*0Σ+reaction atEγ=1.7−3.0GeV [Phys. Rev. C75, 042201 (2007)]

Author: Shifeng Chen, L. C. Dennis, M. Osipenko, H. Avakian, K. Livingston, K. Beard, K. A. Griffioen, J. Donnelly, G. Asryan, M. Battaglieri, R. Bradford, B. A. Mecking, O. P. Dzyubak, R. A. Niyazov, H. Egiyan, J. T. Goetz, R. Dickson, D. Doughty, G. Rosner, Carlos A. Salgado, J. W C McNabb, D. Heddle, A.V. Stavinsky, A. V. Vlassov, Maryam Moteabbed, W. J. Briscoe, E. Pasyuk, K. S. Egiyan, E. S. Smith, D. G. Jenkins, W. Kim, Laird Kramer, D. J. Tedeschi, Kwangsoo Kim, J. Lachniet, A. Tkabladze, S. A. Dytman, S. E. Kuhn, B. B. Niczyporuk, G. Riccardi, K. Mikhailov, B. L. Berman, M. Amarian, N. Guler, R. De Vita, I. Bedlinskiy, Andreas Klein, J. Langheinrich, B. E. Stokes, V. Sapunenko, C. Butuceanu, Sylvain Bouchigny, N. Pivnyuk, E. Wolin, Stephen Taylor, K. Lukashin, Ji Li, U. Thoma, C. Paterson, M. Bellis, P. Rossi, Gerard Gilfoyle, S. McAleer, F. X. Girod, S. A. Morrow, G. Gavalian, P. Stoler, R. S. Hakobyan, V. Batourine, S. Niccolai, C. Djalali, J. P. Ball, D. G. Ireland, M. D. Mestayer, V. Crede, G. Ricco, Y. Prok, V. Mokeev, D. S. Carman, J. Hardie, M. MacCormick, B. Carnahan, F. Sabatié, K. Hicks, J. R. Calarco, P. Ambrozewicz, Michael L. Williams, I. Hleiqawi, S. L. Careccia, V. P. Kubarovsky, S. Strauch, Atilla Gonenc, H. Juengst, D. G. Crabb, J. P. Cummings, G. S. Mutchler, M. Guidal, Z. Krahn, L. C. Smith, E. Munevar, N. A. Baltzell, E. De Sanctis, O. Pogorelko, K. L. Giovanetti, G. Niculescu, R. W. Gothe, N. Baillie, R. A. Miskimen, B. McKinnon, M. Anghinolfi, Larry Weinstein, B. S. Ishkhanov, S. Boiarinov, D. I. Sober, D. Branford, L. Elouadrhiri, M. R. Niroula, Yordanka Ilieva, M. Mirazita, J. M. Laget, M. Kossov, Frank Klein, I. I. Strakovsky, J. D. Kellie, A. Deur, R. G. Fersch, Rakhsha Nasseripour, M. Holtrop, Michael Dugger, B. Zhao, M. Khandaker, Brian Raue, P. Coltharp, Y. G. Sharabian, M. M. Ito, A. I. Ostrovidov, Michael Wood, K. Park, Michael Vineyard, Hong Lu, P. L. Cole, Z. W. Zhao, F. W. Hersman, S. Whisnant, B. M. Preedom, V. S. Serov, Federico Ronchetti, Lorenzo Zana, Volker D. Burkert, A. S. Biselli, Clarisse Tur, P. Nadel-Turonski, H. S. Jo, Tsutomu Mibe, Gerald Feldman, C. E. Hyde-Wright, R. C. Minehart, K. Wang, C. A. Meyer, K. Moriya, R. J. Feuerbach, Jens H. Kuhn, Sergey Kuleshov, S. Tkachenko, N. Benmouna, V. Gyurjyan, M. Ripani, G. V. Fedotov, N. Kalantarians, L. Todor, J. Zhang, H. Bagdasaryan, D. Protopopescu, J. W. Price, L. Guo, S. Pozdniakov, M. Garçon, M. Ungaro, K. Joo, S. S. Stepanyan, A. Yegneswaran, D. P. Weygand, Alexei V. Klimenko, Barry Ritchie, G. E. Dodge, P. V. Degtyarenko, I. Niculescu, D. Lawrence, R. De Masi, R. A. Schumacher, M. Nozar, S. Bültmann, S. Stepanyan, J. Pierce, William Brooks, Hall Crannell, P. Eugenio, M. Taiuti, P. Collins, J. P. Santoro, and Roy Thompson
Subjects: Baryon, Nuclear reaction, Physics, Nuclear and High Energy Physics, Particle physics, Meson, Hadron, Elementary particle, Fermion, Boson, Sigma baryon
Published: 2007

42. π0photoproduction on the proton for photon energies from 0.675 to 2.875 GeV

Author: B. M. Preedom, J. P. Ball, D. S. Carman, L. C. Dennis, B. E. Bonner, R. A. Schumacher, H. Avakian, J. Kuhn, J. P. Santoro, Roy Thompson, B. Carnahan, D. G. Crabb, P. Eugenio, M. Taiuti, P. Collins, R. A. Niyazov, F. Sabatié, S. Bültmann, T. A. Forest, A. I. Ostrovidov, J. Langheinrich, A. C S Lima, W. J. Briscoe, V. Gyurjyan, S. S. Stepanyan, P. Stoler, J. Slamanca, S. A. Philips, S. Stepanyan, H. S. Jo, Gerald Feldman, E. Pasyuk, Valeria Muccifora, J. Pierce, Avraham Klein, D. Doughty, S. A. Dytman, D. G. Ireland, K. Wang, K. Hicks, J. Zhang, H. Bagdasaryan, D. Heddle, L. Elouadrhiri, R. J. Feuerbach, I. I. Strakovsky, Volker D. Burkert, B. B. Niczyporuk, A. S. Biselli, Gerard Gilfoyle, Marco A. Huertas, H. G. Juengst, L. Zana, G. E. Dodge, P. Coltharp, A. Deur, B. E. Stokes, W. K. Brooks, N. Pivnyuk, P. V. Degtyarenko, G. S. Adams, W. Kim, G. Gavalian, A.V. Stavinsky, J. Shaw, G. Niculescu, J. Napolitano, B. L. Berman, J. Donnelly, G. Asryan, O. P. Dzyubak, S. Tkachenko, Federico Ronchetti, Kwangsoo Kim, G. Riccardi, R. Fatemi, C. Butuceanu, Laird Kramer, M. M. Ito, L. M. Qin, F. W. Hersman, M. Kossov, A. V. Vlassov, Sylvain Bouchigny, P. Rossi, E. Anciant, G. V. O'Rielly, M. D. Mestayer, K. Joo, I. Niculescu, D. Lawrence, N. Benmouna, P. Corvisiero, M. Ripani, Carlos A. Salgado, G. Ricco, Michael L. Williams, Victor Mokeev, T. Lee, D. J. Tedeschi, M. Amarian, L. Guo, P. Nadel-Turonski, Tsutomu Mibe, Z. Krahn, Y. Ilieva, M. Spraker, M. Ungaro, Michael Wood, V. S. Serov, M. Guidal, Susan Taylor, S. Strauch, M. Khandaker, N. Baillie, C. Paterson, M. Klusman, S. Boiarinov, J. P. Cummings, R. De Vita, R. A. Miskimen, K. Park, K. S. Egiyan, B. McKinnon, D. G. Jenkins, H. Egiyan, L. C. Maximon, K. Mikhailov, A. Coleman, I. Hleiqawi, H. R. Weller, J. R. Calarco, M. Guillo, I. Bedlinskiy, S. L. Careccia, S. Simionatto, M. Holtrop, S. McAleer, Friedrich Klein, D. Branford, F. X. Girod, Brian Raue, N. Kalantarians, Hall Crannell, J. J. Manak, M. Osipenko, M. Mirazita, K. L. Giovanetti, B. Asavapibhop, Cynthia Marie Hadjidakis, J. M. Laget, A. Tkabladze, J. Yun, D. Cords, Larry Weinstein, J. W C McNabb, D. Rowntree, K. Beard, L. C. Smith, A. Yegneswaran, Michael Dugger, H. O. Funsten, Michael Vineyard, V. P. Kubarovsky, Nicola Bianchi, R. W. Gothe, B. S. Ishkhanov, Kalvir S. Dhuga, C. Marchand, V. Kuznetsov, S. A. Morrow, C. Djalali, L. Todor, A. Empl, R. S. Hakobyan, O. Pogorelko, K. Y. Kim, G. Rosner, R. Nasseripour, E. De Sanctis, D. Protopopescu, J. W. Price, M. R. Niroula, S. Pozdniakov, M. Garçon, G. Audit, C. E. Hyde-Wright, J. Lachniet, D. I. Sober, A. Shafi, P. Ambrozewicz, P. Dragovitsch, M. Bektasoglu, M. Nozar, K. Livingston, S. Niccolai, P. L. Cole, R. Dickson, J. Hardie, N. Guler, S. Barrow, M. Battaglieri, N. A. Baltzell, K. A. Griffioen, J. D. Kellie, Ron L. Workman, R. Bradford, K. Lukashin, G. S. Mutchler, M. Bellis, J. Hu, Alexei V. Klimenko, R. A. Arndt, Barry Ritchie, Bernhard Mecking, K. V. Dharmawardane, R. C. Minehart, Kei Moriya, C. A. Meyer, G. V. Fedotov, Y. Prok, D. P. Weygand, H. Denizli, A. V. Skabelin, Shifeng Chen, J. T. Goetz, V. Sapunenko, Dinko Pocanic, S. E. Kuhn, C. Tur, Elton Smith, J. R. Ficenec, M. Anghinolfi, James Mueller, P. D. Rubin, Y. G. Sharabian, and E. Wolin
Subjects: Physics, Normalization (statistics), Nuclear and High Energy Physics, Particle physics, Photon, Spectrometer, Proton, 010308 nuclear & particles physics, Forward scatter, Scattering, 01 natural sciences, Particle identification, Nuclear physics, 0103 physical sciences, Photon beam, Nuclear Experiment, 010306 general physics
Abstract: Differential cross sections for the reaction $\gamma p \to p \pi^0$ have been measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged photon beam with energies from 0.675 to 2.875 GeV. The results reported here possess greater accuracy in the absolute normalization than previous measurements. They disagree with recent CB-ELSA measurements for the process at forward scattering angles. Agreement with the SAID and MAID fits is found below 1 GeV. The present set of cross sections has been incorporated into the SAID database, and exploratory fits have been extended to 3 GeV. Resonance couplings have been extracted and compared to previous determinations.
Published: 2007

43. Q2dependence of theS11(1535)photocoupling and evidence for aP-wave resonance in η electroproduction

Author: S. A. Morrow, Laird Kramer, P. Dragovitsch, P. Stoler, Barry Ritchie, J. Hardie, S. O. Nelson, K. Hicks, H. G. Juengst, M. L. Leber, Federico Ronchetti, K. Livingston, A.V. Stavinsky, D. J. Tedeschi, J. Kuhn, N. A. Baltzell, R. C. Minehart, C. A. Meyer, G. V. Fedotov, R. Dickson, L. Elouadrhiri, H. Denizli, J. P. Santoro, Roy Thompson, D. P. Weygand, I. Bedlinskiy, K. A. Griffioen, G. Ricco, N. Markov, J. Langheinrich, S. S. Stepanyan, N. Dashyan, S. A. Philips, I. I. Strakovsky, N. Guler, M. Bellis, G. A. Peterson, K. S. Egiyan, Nikolay Shvedunov, A. Deur, V. Frolov, M. J. Amaryan, K. Mikhailov, Shifeng Chen, R. J. Feuerbach, A. I. Ostrovidov, P. Eugenio, R. Fatemi, B. B. Niczyporuk, S. Barrow, W. K. Brooks, M. Taiuti, V. Batourine, I. Hleiqawi, Friedrich Klein, Y. Ilieva, C. Cetina, A. V. Vlassov, S. L. Careccia, N. Kalantarians, J. Hu, J. D. Kellie, J. P. Cummings, S. Simionatto, C. E. Hyde-Wright, Brian Raue, N. Pivnyuk, J. Napolitano, Michael Vineyard, L. Farhi, D. Rowntree, Sergey Kuleshov, N. Baillie, J. T. Goetz, E. Polli, M. Bektasoglu, M. Nozar, V. Gyurjyan, G. V. O'Rielly, P. Collins, Maryam Moteabbed, K. L. Giovanetti, B. Asavapibhop, M. Kossov, M. MacCormick, Valeria Muccifora, Bernhard Mecking, V. Sapunenko, Dinko Pocanic, R. De Vita, J. Zhang, M. Guidal, Z. W. Zhao, G. Gavalian, S. Tkachenko, R. A. Schumacher, Susan Taylor, N. Benmouna, P. L. Cole, M. Spraker, Larry Weinstein, D. Doughty, G. Rosner, L. C. Smith, S. J. Gaff, H. Bagdasaryan, R. Nasseripour, M. Holtrop, D. G. Jenkins, C. Djalali, M. D. Mestayer, E. L. Isupov, M. Ripani, L. Guo, S. Strauch, Gerard Gilfoyle, K. Sabourov, D. Heddle, Nicola Bianchi, D. P. Watts, H. Egiyan, S. Bültmann, M. Ungaro, Michael L. Williams, B. S. Ishkhanov, Sylvain Bouchigny, S. E. Kuhn, T. A. Forest, D. Sokhan, S. Stepanyan, P. Nadel-Turonski, B. E. Stokes, J. W. Price, J. Pierce, Avraham Klein, G. S. Adams, Tsutomu Mibe, G. E. Dodge, J. J. Manak, S. Boiarinov, Michael Dugger, S. McAleer, B. M. Preedom, H. Y. Lu, P. Rossi, H. O. Funsten, F. X. Girod, P. V. Degtyarenko, D. Protopopescu, R. A. Miskimen, B. McKinnon, J. H. Kelley, K. Joo, G. S. Mutchler, S. Pozdniakov, M. Garçon, L. M. Qin, J. Yun, D. Cords, C. Tur, Lorenzo Zana, D. G. Ireland, A. Shafi, A. Yegneswaran, I. Niculescu, M. Battaglieri, V. Crede, D. Lawrence, D. Branford, P. Ambrozewicz, H. Hakobyan, Kwangsoo Kim, G. Riccardi, Gerald Feldman, K. Moriya, U. Thoma, J. R. Calarco, A. Tkabladze, M. Mirazita, J. M. Laget, C. Paterson, Elton Smith, K. Wang, C. Salgado, Atilla Gonenc, M. R. Niroula, M. Klusman, R. Bradford, K. Lukashin, C. Butuceanu, M. Guillo, E. De Sanctis, M. Khandaker, M. Anghinolfi, E. Wolin, H. S. Jo, R. S. Hakobyan, James Mueller, L. El Fassi, P. D. Rubin, J. P. Ball, Y. Prok, Y. G. Sharabian, D. S. Carman, J. Lachniet, D. I. Sober, S. Niccolai, D. G. Crabb, J. Salamanca, J. W C McNabb, A. Coleman, H. R. Weller, Volker D. Burkert, A. S. Biselli, J. Donnelly, G. Asryan, O. P. Dzyubak, R. A. Niyazov, P. Corvisiero, J. Miles, P. Coltharp, M. Osipenko, F. Sabatié, M. M. Ito, K. Beard, R. W. Gothe, Kalvir S. Dhuga, K. Y. Kim, W. Kim, A. V. Skabelin, G. Niculescu, B. Zhao, R. D. Levine, V. Mokeev, F. W. Hersman, L. C. Dennis, B. E. Bonner, H. Avakian, W. J. Briscoe, E. Pasyuk, S. A. Dytman, Patrick Girard, J. Shaw, Michael Wood, K. Hafidi, V. S. Serov, K. Park, V. P. Kubarovsky, A. Empl, and O. Pogorelko
Subjects: Baryon, Scattering cross-section, Physics, Nuclear and High Energy Physics, Cross section.transverse, Particle physics, Amplitude, Photon, Angular distribution, Momentum transfer, Resonance, High Energy Physics::Experiment
Abstract: New cross sections for the reaction $\mathit{ep}\ensuremath{\rightarrow}{e}^{'}\ensuremath{\eta}p$ are reported for total center-of-mass energy $W=1.5\text{\ensuremath{-}}2.3$ GeV and invariant squared momentum transfer ${Q}^{2}=0.13\text{\ensuremath{-}}3.3$ GeV${}^{2}$. This large kinematic range allows the extraction of new information about response functions, photocouplings, and $\ensuremath{\eta}N$ coupling strengths of baryon resonances. A sharp structure is seen at $W~1.7$ GeV. The shape of the differential cross section is indicative of the presence of a $P$-wave resonance that persists to high ${Q}^{2}$. Improved values are derived for the photocoupling amplitude for the ${S}_{11}$(1535) resonance. The new data greatly expand the ${Q}^{2}$ range covered, and an interpretation of all data with a consistent parametrization is provided.
Published: 2007

44. Experimental Study of ExclusiveH2(e,e′p)nReaction Mechanisms at HighQ2

Author: Y. Ilieva, V. Gyurjyan, R. Miskimen, N. Dashyan, J. Zhang, M. Guillo, G. Gavalian, H. Bagdasaryan, S. A. Morrow, S. Tkachenko, S. Mehrabyan, M. Guidal, G. Riccardi, N. Benmouna, E. Wolin, V. Sapunenko, Alexei V. Klimenko, J. P. Ball, D. S. Carman, Dinko Pocanic, R. J. Feuerbach, L. Guo, M. Ungaro, M. Holtrop, P. Eugenio, R. G. Fersch, D. G. Crabb, D. Lawrence, C. Marchand, J. P. Cummings, S. E. Kuhn, A. Deur, L. Todor, D. Protopopescu, S. Pozdniakov, M. Garçon, P. L. Cole, Marco Ripani, Y. Prok, Barry Ritchie, M. Kossov, M. Taiuti, V. Mokeev, S. Bouchigny, R. A. Schumacher, Nikolay Shvedunov, C. Tur, W. K. Brooks, E. De Sanctis, M. Khandaker, Elton Smith, G. Audit, C. E. Hyde-Wright, K. Livingston, C. I O Gordon, R. Dickson, S. Bültmann, D. Cords, P. Nadel-Turonski, Tsutomu Mibe, M. Battaglieri, D. I. Sober, Federico Ronchetti, Sergey Kuleshov, C. Djalali, A. Yegneswaran, M. J. Amaryan, M. Anghinolfi, M. Nozar, N. Kalantarians, N. Guler, S. Stepanyan, Ji Li, P. Coltharp, M. M. Ito, James Mueller, P. Collins, Cynthia Marie Hadjidakis, I. Hleiqawi, J. Pierce, Avraham Klein, R. Fatemi, B. L. Berman, J. Langheinrich, S. S. Stepanyan, Michael Dugger, R. Bradford, G. S. Mutchler, J. J. Melone, J. Lachniet, S. L. Careccia, A. Tkabladze, Z. Krahn, S. Barrow, Michael Wood, A. V. Vlassov, Y. G. Sharabian, G. E. Dodge, H. Y. Lu, H. Denizli, L. C. Smith, E. Munevar, G. V. O'Rielly, P. Ambrozewicz, K. Hafidi, M. D. Mestayer, S. Niccolai, M. Osipenko, B. S. Ishkhanov, P. Rossi, N. A. Baltzell, Friedrich Klein, N. Baillie, P. V. Degtyarenko, V. S. Serov, L. C. Dennis, C. Hanretty, K. L. Giovanetti, Brian Raue, K. A. Griffioen, E. L. Isupov, Z. W. Zhao, M. Bellis, Larry Weinstein, R. S. Hakobyan, S. Strauch, J. Hardie, H. G. Juengst, D. P. Watts, D. Doughty, H. Avakian, R. De Vita, D. G. Ireland, L. El Fassi, Michael L. Williams, V. Crede, M. MacCormick, Shifeng Chen, W. Kim, D. G. Jenkins, I. Niculescu, H. Egiyan, C. Paterson, G. Niculescu, A. V. Skabelin, A.V. Stavinsky, M. R. Niroula, J. R. Calarco, R. De Masi, A. Cazes, Maryam Moteabbed, Bernhard Mecking, B. Zhao, K. V. Dharmawardane, P. Mattione, S. Anefalos Pereira, W. J. Briscoe, E. Pasyuk, S. Boiarinov, B. M. Preedom, Latifa Elouadrhiri, Gerard Gilfoyle, S. McAleer, J. D. Kellie, R. C. Minehart, Kei Moriya, D. J. Tedeschi, F. X. Girod, L. Blaszczyk, C. A. Meyer, S. A. Dytman, D. Sokhan, G. V. Fedotov, J. Kuhn, J. T. Goetz, K. Park, J. Salamanca, I. Bedlinskiy, Laird Kramer, H. S. Jo, F. W. Hersman, B. McKinnon, Lorenzo Zana, J. W C McNabb, J. P. Santoro, V. Batourine, V. P. Kubarovsky, D. P. Weygand, D. Branford, O. Pogorelko, Giovanni Ricco, M. Mirazita, J. M. Laget, Atilla Gonenc, F. Sabatié, N. Gevorgyan, B. B. Niczyporuk, R. W. Gothe, J. W. Price, N. Pivnyuk, H. Hakobyan, Gerald Feldman, G. Rosner, R. Nasseripour, C. Salgado, B. E. Stokes, G. S. Adams, M. Bektasoglu, K. Joo, P. Stoler, C. Butuceanu, Michael Vineyard, K. Hicks, N. Markov, J. Donnelly, G. Asryan, O. P. Dzyubak, R. A. Niyazov, U. Thoma, P. Corvisiero, A. I. Ostrovidov, K. S. Egiyan, Volker D. Burkert, A. S. Biselli, and K. Mikhailov
Subjects: Physics, Nuclear reaction, Reaction mechanism, Particle physics, 010308 nuclear & particles physics, Partial wave analysis, Hadron, General Physics and Astronomy, Elementary particle, 01 natural sciences, Delta baryon, Chemical kinetics, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: The reaction 2H(e,e'p)n has been studied with full kinematic coverage for photon virtuality 1.75 NN transition is the primary contribution at higher momenta.
Published: 2007

45. Cross sections for theγp→K*0Σ+reaction atEγ=1.7–3.0GeV

Author: S. McAleer, H. G. Juengst, F. X. Girod, J. Kuhn, A.V. Stavinsky, A. V. Vlassov, R. W. Gothe, Roy Thompson, Atilla Gonenc, R. De Vita, J. W. Price, D. J. Tedeschi, U. Thoma, S. A. Morrow, B. E. Stokes, P. Coltharp, Michael Vineyard, V. Sapunenko, G. Ricco, Latifa Elouadrhiri, C. Djalali, M. M. Ito, J. P. Cummings, I. Bedlinskiy, M. Kossov, Hall Crannell, R. C. Minehart, S. E. Kuhn, C. A. Meyer, K. Park, A. Tkabladze, Maryam Moteabbed, L. C. Smith, E. Munevar, P. Ambrozewicz, Bernhard Mecking, B. M. Preedom, G. V. Fedotov, Friedrich Klein, C. Tur, M. Osipenko, B. S. Ishkhanov, H. Egiyan, B. Zhao, Z. W. Zhao, P. Eugenio, Lorenzo Zana, J. P. Santoro, M. Taiuti, Brian Raue, G. E. Dodge, H. Y. Lu, V. Gyurjyan, E. De Sanctis, K. Beard, H. S. Jo, M. R. Niroula, V. P. Kubarovsky, D. P. Weygand, M. Battaglieri, R. S. Hakobyan, J. Zhang, P. Stoler, G. Gavalian, V. Crede, S. Tkachenko, D. G. Jenkins, Elton Smith, N. Benmouna, M. Ripani, Gerald Feldman, K. Wang, P. V. Degtyarenko, Daniel S. Carman, C. Salgado, H. Bagdasaryan, R. Bradford, J. Lachniet, D. I. Sober, J. R. Calarco, O. Pogorelko, M. Anghinolfi, P. Collins, Y. G. Sharabian, L. Guo, M. Ungaro, B. L. Berman, P. Nadel-Turonski, Tsutomu Mibe, J. W C McNabb, Federico Ronchetti, Michael Dugger, I. Niculescu, Alexei V. Klimenko, Ji Li, D. Lawrence, K. Hicks, G. Rosner, Barry Ritchie, R. Nasseripour, S. Niccolai, F. W. Hersman, K. S. Egiyan, C. E. Hyde-Wright, Kwangsoo Kim, S. Strauch, M. D. Mestayer, K. Joo, G. Riccardi, K. Moriya, R. A. Niyazov, Shifeng Chen, B. B. Niczyporuk, R. De Masi, R. A. Schumacher, K. Mikhailov, A. Yegneswaran, M. Bellis, Michael L. Williams, C. Paterson, M. Amarian, N. Pivnyuk, J. Hardie, C. Butuceanu, S. Boiarinov, Sergey Kuleshov, M. Nozar, Sylvain Bouchigny, N. Kalantarians, J. T. Goetz, S. Bültmann, P. Rossi, R. G. Fersch, J. Donnelly, G. Asryan, O. P. Dzyubak, P. L. Cole, S. Whisnant, S. Stepanyan, I. I. Strakovsky, M. Guidal, J. Pierce, Avraham Klein, G. S. Mutchler, A. Deur, W. K. Brooks, M. Holtrop, V. Batourine, B. Carnahan, F. Sabatié, E. Wolin, J. Langheinrich, S. S. Stepanyan, J. P. Ball, Y. Prok, N. A. Baltzell, K. A. Griffioen, D. G. Crabb, J. D. Kellie, V. Mokeev, K. Lukashin, W. Kim, G. Niculescu, Michael Wood, V. S. Serov, L. C. Dennis, H. Avakian, M. MacCormick, I. Hleiqawi, Laird Kramer, W. J. Briscoe, E. Pasyuk, S. A. Dytman, S. L. Careccia, Gerard Gilfoyle, K. L. Giovanetti, S. Taylor, Y. Ilieva, Larry Weinstein, K. Livingston, R. Dickson, N. Guler, L. Todor, D. Protopopescu, A. I. Ostrovidov, M. Khandaker, S. Pozdniakov, M. Garçon, Z. Krahn, N. Baillie, D. G. Ireland, D. Doughty, R. A. Miskimen, B. McKinnon, Volker D. Burkert, A. S. Biselli, D. Heddle, D. Branford, M. Mirazita, J. M. Laget, and R. J. Feuerbach
Subjects: Quark, Physics, Nuclear and High Energy Physics, Range (particle radiation), Particle physics, Photon, Meson, 010308 nuclear & particles physics, Scalar (mathematics), Dalitz plot, Photon energy, 01 natural sciences, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Tensor, Nuclear Experiment, 010306 general physics
Abstract: Differential cross sections for the reaction $$\gamma p \to K^{*0} \Sigma^+$$ are presented at nine bins in photon energy in the range from 1.7 to 3.0 GeV. The \kstar was detected by its decay products, $$K^+\pi^-$$, in the CLAS detector at Jefferson Lab. These data are the first \kstar photoproduction cross sections ever published over a broad range of angles. Comparison with a theoretical model based on the vector and tensor $K^*$-quark couplings shows good agreement with the data in general, after adjusting the model's two parameters in a fit to our data. Disagreement between the data at forward angles and the global angle-energy fit to the model suggests that the role of scalar $$\kappa$$ meson exchange in $t$-channel diagrams should be investigated.
Published: 2007

46. Separated structure functions for the exclusive electroproduction ofK+ΛandK+Σ0final states

Author: Y. Ilieva, L. C. Dennis, B. E. Bonner, J. Kuhn, J. P. Santoro, Elton Smith, D. P. Watts, Roy Thompson, Nicola Bianchi, R. W. Gothe, H. Avakian, H. Egiyan, Latifa Elouadrhiri, R. C. Minehart, Kei Moriya, D. G. Ireland, P. Eugenio, V. Crede, M. Taiuti, P. Collins, Michael Dugger, C. A. Meyer, H. O. Funsten, K. Livingston, P. L. Cole, M. Anghinolfi, G. V. Fedotov, R. A. Miskimen, B. McKinnon, K. Y. Kim, N. Markov, A. Tkabladze, J. R. Calarco, E. Wolin, R. Dickson, I. I. Strakovsky, James Mueller, D. Rowntree, D. Branford, E. De Sanctis, A. Deur, K. S. Egiyan, W. J. Briscoe, P. D. Rubin, J. P. Ball, B. Zhao, E. Pasyuk, M. Mirazita, J. M. Laget, N. Guler, J. Lachniet, D. I. Sober, A. I. Ostrovidov, D. Doughty, W. K. Brooks, Y. G. Sharabian, D. P. Weygand, K. Mikhailov, L. El Fassi, D. G. Crabb, V. Batourine, S. A. Dytman, Volker D. Burkert, R. Fatemi, G. V. O'Rielly, D. Heddle, Daniel S. Carman, A. S. Biselli, S. Barrow, A. V. Vlassov, G. Gavalian, F. W. Hersman, P. Dragovitsch, Z. W. Zhao, L. Farhi, S. Tkachenko, V. Sapunenko, D. Sayre, N. Benmouna, M. Ripani, P. Nadel-Turonski, Dinko Pocanic, D. G. Jenkins, D. Protopopescu, Kwangsoo Kim, G. Riccardi, M. Amarian, D. Lawrence, Nikolay Shvedunov, J. P. Cummings, C. E. Hyde-Wright, A. V. Skabelin, K. Park, S. Pozdniakov, M. Garçon, C. Butuceanu, Tsutomu Mibe, P. Stoler, R. De Vita, Laird Kramer, N. Baillie, A. Shafi, S. McAleer, M. Osipenko, F. Sabatié, N. Kalantarians, S. E. Kuhn, F. X. Girod, K. Beard, M. Kossov, P. Coltharp, S. Niccolai, K. Hicks, Valeria Muccifora, B. L. Berman, Sylvain Bouchigny, C. Tur, Y. Prok, Barry Ritchie, Kalvir S. Dhuga, L. M. Qin, Gerard Gilfoyle, R. J. Feuerbach, M. M. Ito, Sergey Kuleshov, M. Guillo, M. Bektasoglu, P. Rossi, M. Nozar, V. P. Kubarovsky, J. Donnelly, G. Asryan, V. Frolov, D. Sokhan, O. P. Dzyubak, R. A. Niyazov, C. Paterson, Atilla Gonenc, J. W. Price, M. Klusman, W. Kim, J. Hardie, M. MacCormick, I. Hleiqawi, L. C. Smith, Shifeng Chen, B. S. Ishkhanov, S. L. Careccia, P. Corvisiero, S. Simionatto, G. Niculescu, K. L. Giovanetti, B. Asavapibhop, S. Taylor, Larry Weinstein, M. R. Niroula, M. Khandaker, H. G. Juengst, M. Guidal, M. Bellis, J. Salamanca, V. Mokeev, M. Holtrop, A.V. Stavinsky, C. Cetina, J. T. Goetz, Jian Zhang, E. Polli, Michael Vineyard, J. Langheinrich, S. S. Stepanyan, S. A. Philips, D. J. Tedeschi, I. Bedlinskiy, J. W C McNabb, J. Hu, M. D. Mestayer, E. L. Isupov, B. B. Niczyporuk, S. Boiarinov, Maryam Moteabbed, N. Pivnyuk, B. M. Preedom, Bernhard Mecking, Lorenzo Zana, J. Napolitano, H. Hakobyan, H. S. Jo, Gerald Feldman, K. Wang, C. Salgado, S. A. Morrow, C. Djalali, M. Battaglieri, R. Bradford, P. Ambrozewicz, K. Lukashin, N. A. Baltzell, K. A. Griffioen, J. J. Manak, J. D. Kellie, S. Strauch, G. S. Mutchler, Mathew Williams, V. Gyurjyan, H. Bagdasaryan, L. Guo, M. Ungaro, K. Joo, J. Yun, D. Cords, A. Yegneswaran, B. E. Stokes, G. Ricco, G. Rosner, R. Nasseripour, A. Empl, O. Pogorelko, Patrick Girard, Michael Wood, K. Hafidi, V. S. Serov, Friedrich Klein, Brian Raue, Federico Ronchetti, G. E. Dodge, H. Y. Lu, P. V. Degtyarenko, I. Niculescu, R. De Masi, R. A. Schumacher, S. Bültmann, T. A. Forest, S. Stepanyan, J. Pierce, Avraham Klein, and N. Dashyan
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Proton, 010308 nuclear & particles physics, Momentum transfer, Hyperon, Sigma, Strangeness, Lambda, 01 natural sciences, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Production (computer science), Nuclear Experiment, 010306 general physics, Energy (signal processing)
Abstract: We report measurements of the exclusive electroproduction of K{sup +}{lambda} and K{sup +}{sigma}{sup 0} final states from a proton target using the Continuous Electron Beam Accelerator Facility (CEBAF) large-acceptance spectrometer (CLAS) detector at the Thomas Jefferson National Accelerator Facility. The separated structure functions {sigma}{sub T},{sigma}{sub L},{sigma}{sub TT}, and {sigma}{sub LT} were extracted from the {phi}- and {epsilon}-dependent differential cross sections taken with electron beam energies of 2.567, 4.056, and 4.247 GeV. This analysis represents the first {sigma}{sub L}/{sigma}{sub T} separation with the CLAS detector, and the first measurement of the kaon electroproduction structure functions away from parallel kinematics. The data span a broad range of momentum transfers from 0.5{
Published: 2007

47. First measurement of beam-recoil observablesCxandCzin hyperon photoproduction

Author: V. Gyurjyan, L. C. Dennis, B. E. Bonner, H. Avakian, Maryam Moteabbed, Bernhard Mecking, J. Zhang, K. V. Dharmawardane, H. Bagdasaryan, K. Park, F. Sabatiã, V. P. Kubarovsky, A. Empl, O. Pogorelko, S. A. Morrow, K. Lukashin, W. J. Briscoe, E. Pasyuk, L. C. Smith, V. Sapunenko, Dinko Pocanic, S. A. Dytman, B. S. Ishkhanov, Barry Ritchie, J. Kuhn, Hall Crannell, Marco Ripani, S. E. Kuhn, E. Anciant, Roy Thompson, C. Marchand, M. Bellis, J. Shaw, M. R. Niroula, Michael Wood, J. P. Cummings, K. Hafidi, V. S. Serov, L. Elouadrhiri, C. Tur, B. P. Quinn, R. A. Schumacher, G. V. O'Rielly, R. Fatemi, B. Zhao, Kei Moriya, Federico Ronchetti, C. A. Meyer, Victor Mokeev, Z. W. Zhao, J. Hu, M. Khandaker, G. V. Fedotov, M. Kossov, L. Guo, M. Ungaro, B. L. Berman, D. G. Jenkins, Cynthia Marie Hadjidakis, S. Bültmann, T. A. Forest, A. V. Vlassov, I. Popa, I. I. Strakovsky, J. Langheinrich, S. S. Stepanyan, S. A. Philips, A. Coleman, S. Stepanyan, P. Eugenio, B. B. Niczyporuk, H. R. Weller, N. Baillie, M. Battaglieri, R. A. Miskimen, B. McKinnon, P. Dragovitsch, D. P. Weygand, M. Taiuti, J. Pierce, Avraham Klein, Shifeng Chen, Michael Dugger, Kwangsoo Kim, G. Riccardi, N. Pivnyuk, L. M. Qin, J. Napolitano, H. O. Funsten, R. Bradford, J. Yun, D. Cords, Friedrich Klein, M. Osipenko, F. W. Hersman, G. E. Dodge, S. McAleer, F. X. Girod, A. Yegneswaran, C. Butuceanu, R. J. Feuerbach, A. Deur, H. Denizli, Brian Raue, D. Branford, P. V. Degtyarenko, R. De Vita, N. Guler, P. Collins, Marco A. Huertas, M. Mirazita, J. M. Laget, P. L. Cole, M. Guidal, W. K. Brooks, K. Beard, J. Hardie, G. Niculescu, A. V. Skabelin, I. Niculescu, Giovanni Ricco, Atilla Gonenc, M. D. Mestayer, J. J. Manak, H. G. Juengst, P. Coltharp, D. Lawrence, M. Holtrop, J. W. Price, C. Paterson, R. De Masi, E. L. Isupov, P. Nadel-Turonski, M. M. Ito, C. Djalali, R. W. Gothe, Tsutomu Mibe, A.V. Stavinsky, M. Klusman, Michael L. Williams, E. De Sanctis, M. MacCormick, J. T. Goetz, J. Lachniet, D. I. Sober, G. Audit, C. E. Hyde-Wright, E. Polli, M. Guillo, J. D. Kellie, Valeria Muccifora, D. J. Tedeschi, K. Y. Kim, G. Gavalian, S. Tkachenko, V. Batourine, S. Boiarinov, B. M. Preedom, H. Y. Lu, Sergey Kuleshov, I. Bedlinskiy, M. Bektasoglu, N. Benmouna, M. Nozar, Gerard Gilfoyle, E. Wolin, B. Carnahan, Elton Smith, P. Ambrozewicz, D. Sokhan, A. Tkabladze, Nikolay Shvedunov, D. Rowntree, Lorenzo Zana, J. P. Santoro, W. Kim, J. P. Ball, Y. Prok, U. Thoma, R. S. Hakobyan, M. Anghinolfi, D. S. Carman, Sylvain Bouchigny, L. El Fassi, N. Natasha, N. Kalantarians, James Mueller, S. Niccolai, D. G. Crabb, J. Salamanca, Susan Taylor, P. Rossi, J. W C McNabb, D. P. Watts, H. Egiyan, P. D. Rubin, Y. G. Sharabian, V. Crede, J. R. Calarco, B. E. Stokes, G. S. Adams, H. S. Jo, K. Joo, N. A. Baltzell, K. A. Griffioen, N. Markov, Laird Kramer, Y. Ilieva, S. Strauch, G. S. Mutchler, A. I. Ostrovidov, A. C S Lima, D. G. Ireland, Volker D. Burkert, A. S. Biselli, Nicola Bianchi, L. Todor, D. Protopopescu, S. Pozdniakov, M. Garçon, G. Rosner, R. Nasseripour, A. Shafi, K. S. Egiyan, K. Livingston, R. Dickson, K. Mikhailov, S. Barrow, P. Stoler, K. Hicks, J. Donnelly, G. Asryan, O. P. Dzyubak, R. A. Niyazov, M. J. Amaryan, I. Hleiqawi, S. L. Careccia, S. Simionatto, P. Corvisiero, K. L. Giovanetti, B. Asavapibhop, M. Spraker, Larry Weinstein, D. Doughty, D. Heddle, H. Hakobyan, Gerald Feldman, K. Wang, C. Salgado, and Michael Vineyard
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Photon, 010308 nuclear & particles physics, Bremsstrahlung, Hyperon, Observable, Lambda, Polarization (waves), 01 natural sciences, Induced polarization, Nuclear physics, Recoil, 0103 physical sciences, Nuclear Experiment, 010306 general physics
Abstract: Spin transfer from circularly polarized real photons to recoiling hyperons has been measured for the reactions $$\vec\gamma + p \to K^+ + \vec\Lambda$$ and $$\vec\gamma + p \to K^+ + \vec\Sigma^0$$. The data were obtained using the CLAS detector at Jefferson Lab for center-of-mass energies $W$ between 1.6 and 2.53 GeV, and for $$-0.85
Published: 2007

48. Quark-hadron duality in spin structure functionsg1pandg1d

Author: Carlos A. Salgado, M. Amarian, Nikolay Shvedunov, S. Bültmann, M. Guidal, L. Morand, T. A. Forest, P. Dragovitsch, J. Pierce, Avraham Klein, Elton Smith, Gerard Gilfoyle, S. Niccolai, M. Holtrop, K. Livingston, G. E. Dodge, E. Wolin, Hall Crannell, Michael Vineyard, P. V. Degtyarenko, M. Anghinolfi, Hong Lu, J. Hardie, I. Niculescu, James Mueller, B. M. Preedom, D. Lawrence, P. D. Rubin, Y. G. Sharabian, P. Eugenio, R. De Masi, Lorenzo Zana, J. P. Santoro, V. Batourine, H. G. Juengst, J. Langheinrich, S. S. Stepanyan, S. A. Philips, R. Fatemi, B. Carnahan, F. Sabatié, H. S. Jo, D. Doughty, A. V. Vlassov, M. Taiuti, J. P. Ball, Y. Prok, A.V. Stavinsky, L. Elouadrhiri, N. Guler, P. Nadel-Turonski, Tsutomu Mibe, V. Gyurjyan, Federico Ronchetti, R. J. Feuerbach, V. Sapunenko, V. Crede, D. J. Tedeschi, J. P. Cummings, P. Stoler, Dinko Pocanic, D. Heddle, Daniel S. Carman, J. Zhang, B. E. Stokes, D. G. Crabb, S. E. Kuhn, C. E. Hyde-Wright, G. Ricco, J. R. Calarco, H. Denizli, G. Gavalian, N. Baillie, H. Bagdasaryan, J. W. Price, G. V. O'Rielly, I. Bedlinskiy, S. Tkachenko, M. Kossov, C. Tur, Ji Li, S. Barrow, A. Deur, K. Hicks, R. A. Miskimen, B. McKinnon, G. S. Adams, Jeffrey P. Donnelly, N. Benmouna, M. Ripani, Shifeng Chen, M. D. Mestayer, R. DeVita, Sergey Kuleshov, M. Bektasoglu, M. Nozar, E. L. Isupov, Cynthia Marie Hadjidakis, Michael L. Williams, L. M. Qin, J. W C McNabb, K. S. Egiyan, D. Branford, Friedrich Klein, Michael Dugger, P. L. Cole, S. Boiarinov, W. K. Brooks, J. Lachniet, Z. W. Zhao, A. Tkabladze, A. V. Skabelin, Brian Raue, H. O. Funsten, C. Paterson, J. T. Goetz, E. Polli, S. Stepanyan, P. Collins, M. Mirazita, S. A. Morrow, J. M. Laget, Victor Mokeev, J. J. Manak, D. Rowntree, M. Klusman, L. Todor, C. Djalali, K. Mikhailov, Marco A. Huertas, L. Guo, M. Ungaro, D. G. Jenkins, R. S. Hakobyan, Susan Taylor, E. Golovatch, Sylvain Bouchigny, D. Protopopescu, S. Pozdniakov, M. Garçon, C. D. Keith, Kwangsoo Kim, G. Riccardi, H. Egiyan, P. Rossi, P. Ambrozewicz, R. C. Minehart, C. Butuceanu, K. Joo, J. Yun, D. Cords, M. MacCormick, U. Thoma, G. Asryan, I. Hleiqawi, C. A. Meyer, A. Yegneswaran, O. P. Dzyubak, R. A. Niyazov, G. V. Fedotov, M. Bellis, S. L. Careccia, P. Corvisiero, E. De Sanctis, J. Kuhn, Roy Thompson, K. L. Giovanetti, D. I. Sober, M. Guillo, Larry Weinstein, B. B. Niczyporuk, S. McAleer, N. Pivnyuk, J. Napolitano, M. Khandaker, Y. Ilieva, F. X. Girod, D. P. Weygand, Atilla Gonenc, G. Rosner, P. Bosted, R. Nasseripour, P. Coltharp, M. M. Ito, L. C. Smith, B. S. Ishkhanov, A. Cazes, Maryam Moteabbed, Bernhard Mecking, M. R. Niroula, K. V. Dharmawardane, M. Osipenko, K. Beard, W. Kim, M. Battaglieri, G. Niculescu, R. Bradford, K. Lukashin, L. C. Dennis, Laird Kramer, B. E. Bonner, H. Avakian, E. Pasyuk, S. A. Dytman, N. Markov, K. Park, A. I. Ostrovidov, A. C S Lima, D. G. Ireland, Volker D. Burkert, A. S. Biselli, V. P. Kubarovsky, O. Pogorelko, J. Shaw, Michael Wood, K. Hafidi, V. S. Serov, S. Strauch, R. Suleiman, G. S. Mutchler, N. A. Baltzell, K. A. Griffioen, J. D. Kellie, R. W. Gothe, K. Y. Kim, B. Zhao, F. W. Hersman, and R. A. Schumacher
Subjects: Physics, Quantum chromodynamics, Quark, Nuclear and High Energy Physics, Particle physics, Proton, 010308 nuclear & particles physics, Hadron, Duality (optimization), 01 natural sciences, Resonance (particle physics), Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon, Spin-½
Abstract: New measurements of the spin structure functions of the proton and deuteron g1p(x,Q2) and g1d(x,Q2) in the nucleon resonance region are compared with extrapolations of target-mass-corrected next-to-leading-order (NLO) QCD fits to higher energy data. Averaged over the entire resonance region (W 1.7 GeV2. This global duality appears to result from cancellations among the prominent local resonance regions: in particular strong sigma{3/2} contributions in the Delta(1232) region appear to be compensated by strong sigma{1/2} contributions in the resonance region centered on 1.5 GeV. These results are encouraging for the extension of NLO QCD fits to lower W and Q2 than have been used previously.
Published: 2007

49. Experimental study of exclusive 2H(e,e'p)n reaction mechanisms at high Q2

Author: K S, Egiyan, G, Asryan, N, Gevorgyan, K A, Griffioen, J M, Laget, S E, Kuhn, G, Adams, M J, Amaryan, P, Ambrozewicz, M, Anghinolfi, G, Audit, H, Avakian, H, Bagdasaryan, N, Baillie, J P, Ball, N A, Baltzell, S, Barrow, V, Batourine, M, Battaglieri, I, Bedlinskiy, M, Bektasoglu, M, Bellis, N, Benmouna, B L, Berman, A S, Biselli, L, Blaszczyk, S, Bouchigny, S, Boiarinov, R, Bradford, D, Branford, W J, Briscoe, W K, Brooks, S, Bültmann, V D, Burkert, C, Butuceanu, J R, Calarco, S L, Careccia, D S, Carman, A, Cazes, S, Chen, P L, Cole, P, Collins, P, Coltharp, D, Cords, P, Corvisiero, D, Crabb, V, Crede, J P, Cummings, N, Dashyan, R, De Masi, R, De Vita, E, De Sanctis, P V, Degtyarenko, H, Denizli, L, Dennis, A, Deur, K V, Dharmawardane, R, Dickson, C, Djalali, G E, Dodge, J, Donnelly, D, Doughty, M, Dugger, S, Dytman, O P, Dzyubak, H, Egiyan, L, El Fassi, L, Elouadrhiri, P, Eugenio, R, Fatemi, G, Fedotov, G, Feldman, R J, Feuerbach, R, Fersch, M, Garçon, G, Gavalian, G P, Gilfoyle, K L, Giovanetti, F X, Girod, J T, Goetz, A, Gonenc, C I O, Gordon, R W, Gothe, M, Guidal, M, Guillo, N, Guler, L, Guo, V, Gyurjyan, C, Hadjidakis, K, Hafidi, H, Hakobyan, R S, Hakobyan, C, Hanretty, J, Hardie, F W, Hersman, K, Hicks, I, Hleiqawi, M, Holtrop, C E, Hyde-Wright, Y, Ilieva, D G, Ireland, B S, Ishkhanov, E L, Isupov, M M, Ito, D, Jenkins, H S, Jo, K, Joo, H G, Juengst, N, Kalantarians, J D, Kellie, M, Khandaker, W, Kim, A, Klein, F J, Klein, A V, Klimenko, M, Kossov, Z, Krahn, L H, Kramer, V, Kubarovsky, J, Kuhn, S V, Kuleshov, J, Lachniet, J, Langheinrich, D, Lawrence, Ji, Li, K, Livingston, H Y, Lu, M, Maccormick, C, Marchand, N, Markov, P, Mattione, S, McAleer, B, McKinnon, J W C, McNabb, B A, Mecking, S, Mehrabyan, J J, Melone, M D, Mestayer, C A, Meyer, T, Mibe, K, Mikhailov, R, Minehart, M, Mirazita, R, Miskimen, V, Mokeev, K, Moriya, S A, Morrow, M, Moteabbed, J, Mueller, E, Munevar, G S, Mutchler, P, Nadel-Turonski, R, Nasseripour, S, Niccolai, G, Niculescu, I, Niculescu, B B, Niczyporuk, M R, Niroula, R A, Niyazov, M, Nozar, G V, O'Rielly, M, Osipenko, A I, Ostrovidov, K, Park, E, Pasyuk, C, Paterson, S, Anefalos Pereira, J, Pierce, N, Pivnyuk, D, Pocanic, O, Pogorelko, S, Pozdniakov, B M, Preedom, J W, Price, Y, Prok, D, Protopopescu, B A, Raue, G, Riccardi, G, Ricco, M, Ripani, B G, Ritchie, F, Ronchetti, G, Rosner, P, Rossi, F, Sabatié, J, Salamanca, C, Salgado, J P, Santoro, V, Sapunenko, R A, Schumacher, V S, Serov, Y G, Sharabian, N V, Shvedunov, A V, Skabelin, E S, Smith, L C, Smith, D I, Sober, D, Sokhan, A, Stavinsky, S S, Stepanyan, S, Stepanyan, B E, Stokes, P, Stoler, S, Strauch, M, Taiuti, D J, Tedeschi, U, Thoma, A, Tkabladze, S, Tkachenko, L, Todor, C, Tur, M, Ungaro, M F, Vineyard, A V, Vlassov, D P, Watts, L B, Weinstein, D P, Weygand, M, Williams, E, Wolin, M H, Wood, A, Yegneswaran, L, Zana, J, Zhang, B, Zhao, and Z W, Zhao
Abstract: The reaction 2H(e,e'p)n has been studied with full kinematic coverage for photon virtuality 1.75Q25.5 GeV2. Comparisons of experimental data with theory indicate that for very low values of neutron recoil momentum (p(n)100 MeV/c) the neutron is primarily a spectator and the reaction can be described by the plane-wave impulse approximation. For 100p(n)750 MeV/c, proton-neutron rescattering dominates the cross section, while Delta production followed by the NDelta--NN transition is the primary contribution at higher momenta.
Published: 2007

50. ISOBAR CHANNELS IN THE PRODUCTION OF PI+ PI- PAIRS ON A PROTON BY VIRTUAL PHOTONS

Author: G. V. Fedotov, Marco Ripani, J. Ricco, E. L. Isupov, V. V. Sapunenko, M. Battaglieri, B. S. Ishkhanov, E. N. Golovach, N. Markov, M. Taiuti, A. A. Boluchevskii, L. Elouardrhiri, Nikolay Shvedunov, V. I. Mokeev, Volker D. Burkert, and K. Joo
Subjects: Physics, NUCLEON-RESONANCE EXCITATION, Nuclear and High Energy Physics, Particle physics, Meson, Nuclear Theory, Hadron, Virtual particle, ELECTROPRODUCTION, Resonance (particle physics), Atomic and Molecular Physics, and Optics, Nuclear physics, Pair production, Pion, Isobar, Nuclear Experiment, Nucleon, ENERGY REGION, NUCLEON-RESONANCE EXCITATION, ENERGY REGION, ELECTROPRODUCTION
Abstract: A new approach is developed for evaluating contributions of various isobar channels to the double charged-pion production in the reactions γr,vp → π+π−p. This approach makes it possible to determine both respective cross sections and amplitudes for quasi-two-particle channels from a fit to data on cross sections for a three-particle final state. The diffractive anzatz, which is widely used to describe rho-meson production, is modified to meet the purpose of the description of data in the near-threshold and subthreshold regions. The cross sections for rho-meson electroproduction in the energy region of nucleon-resonance excitation are determined for the first time on the basis of the latest data of the CLAS Collaboration.
Published: 2007

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