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26 results on '"Eberhard Klempt"'

1. Observation of the pη′ Cusp in the New Precise Beam Asymmetry Σ Data for γp→pη

Author

Cbelsa, F. Afzal, L Richter, S. Ciupka, U-G Meißner, V. Metag, W. Meyer, M. Grüner, K. Koop, T. Seifen, Lilian Witthauer, H. Kalinowsky, Matthew Lang, D. Piontek, N. Stausberg, M. Urban, I. V. Lopatin, A. V. Sarantsev, T. C. Jude, Frank Frommberger, M. Becker, B. Mitlasóczki, H. Schmieden, M. Dieterle, V. Sokhoyan, H. van Pee, D. E. Bayadilov, P. Klassen, K. Spieker, K. Nikonov, B. Krusche, A. B. Gridnev, Mariana Nanova, B. Salisbury, Wolfgang Hillert, J. Hannappel, C. Sowa, J. Hoff, E. Gutz, Ch. Honisch, J. Schultes, H. Dutz, G. Urff, Ch. Schmidt, Y. Wunderlich, Ulrich Wiedner, Frank Klein, V. Crede, U. Thoma, D. Elsner, S. Friedrich, A. Wilson, R. W. Novotny, Ph. Hoffmeister, A. Thiel, V. Novinskiy, P. Mahlberg, A. V. Anisovich, Francesco Messi, I. Keshelashvili, Ch. Wendel, F. Kalischewski, K.-T. Brinkmann, T. Triffterer, P. Kroenert, G. Reicherz, D. Walther, Jörg H. Müller, Jens Hartmann, D. Rönchen, T. Rostomyan, M. Gottschall, E. Blanke, D. Schaab, R. Beck, Ch. Hammann, A. Winnebeck, J. Müllers, Eberhard Klempt, and V. A. Nikonov

Subjects
Physics, Photon, Meson, media_common.quotation_subject, Partial wave analysis, Nuclear Theory, Solid angle, General Physics and Astronomy, Observable, Polarization (waves), 01 natural sciences, Asymmetry, Nuclear physics, 0103 physical sciences, Physics::Accelerator Physics, Nuclear Experiment, 010306 general physics, Nucleon, media_common
Abstract

Data on the beam asymmetry Σ in the photoproduction of η mesons off protons are reported for tagged photon energies from 1130 to 1790 MeV (mass range from W=1748 MeV to W=2045 MeV). The data cover the full solid angle that allows for a precise moment analysis. For the first time, a strong cusp effect in a polarization observable has been observed that is an effect of a branch-point singularity at the pη^{'} threshold [E_{γ}=1447 MeV (W=1896 MeV)]. The latest BnGa partial wave analysis includes the new beam asymmetry data and yields a strong indication for the N(1895)1/2^{-} nucleon resonance, demonstrating the importance of including all singularities for a correct determination of partial waves and resonance parameters.

Published
2020

2. First Measurements of the Double-Polarization Observables F , P , and H in ω Photoproduction off Transversely Polarized Protons in the N* Resonance Region

Author

Eberhard Klempt, O. Cortes, C. Hanretty, K. A. Griffioen, M. Ungaro, V. A. Nikonov, X. Wei, B. S. Ishkhanov, O. Soto, C. D. Keith, S. Strauch, G. Khachatryan, F. X. Girod, M. Osipenko, A. D'Angelo, Eugene Pasyuk, H. S. Jo, A. El Alaoui, W. J. Briscoe, Y. Ilieva, Aditya R. Khanal, Dustin Keller, L. Barion, F. Sabatié, I. I. Strakovsky, L. Guo, Alessandro Rizzo, A. V. Anisovich, L. Lanza, J. Brock, V. Mokeev, E. L. Isupov, Nicholas Zachariou, K Nakayama, M. C. Kunkel, P. Nadel-Turonski, Rong Wang, R. De Vita, A. Deur, R. A. Schumacher, Michael Wood, P. Lenisa, W. Phelps, Barry Ritchie, S. Boiarinov, K. Hafidi, G. Ciullo, Y. Prok, Iu. Skorodumina, S Niccolai, P. Eugenio, W. Kim, G. Niculescu, D. S. Carman, W. K. Brooks, I. Bedlinskiy, C. A. Meyer, D. Payette, K. Livingston, Sylvester Joosten, G. Rosner, H. Egiyan, Andrea Celentano, T. B. Hayward, J. Pierce, Jie Zhang, S. Adhikari, Friedrich Klein, D. G. Jenkins, M. Taiuti, K. P. Adhikari, Brian Raue, D. P. Watts, D. Marchand, Y. G. Sharabian, A. Movsisyan, S. Diehl, M. Ripani, C. Salgado, C. Carlin, S. Fegan, M. L. Kabir, A. V. Sarantsev, M. Battaglieri, N. Tyler, B. Duran, V. P. Kubarovsky, E. Voutier, J. A. Tan, U. Shrestha, V. Crede, D. Riser, Chaden Djalali, O. Pogorelko, M. Khachatryan, Michael Dugger, T. Mineeva, H. Avakian, E. Golovatch, A Fradi, R. Dupre, H. Voskanyan, Nikolaos Sparveris, F. Cao, P. Roy, N C Wei, N. K. Walford, R. A. Montgomery, M. Guidal, E. De Sanctis, N. Dashyan, A. Kim, P. Chatagnon, I. J. D. MacGregor, Michael Paolone, M. Holtrop, M. Hattawy, R. W. Gothe, M Ehrhart, K. Hicks, Luciano Pappalardo, S. Park, Taya Chetry, M. Contalbrigo, G. Angelini, Sergey Kuleshov, D. G. Meekins, L. El Fassi, A. I. Ostrovidov, D. G. Ireland, Volker D. Burkert, A. S. Biselli, M. Khandaker, B. McKinnon, D. Heddle, P. L. Cole, M. L. Seely, B. Torayev, Feng Huang, R. Paremuzyan, Sandra K. Johnston, D. Protopopescu, Z. W. Zhao, Nicholas M. Harrison, Gerard Gilfoyle, D. Sokhan, A. Filippi, and C. Munoz Camacho

Subjects
Physics, Photon, Spectrometer, Proton, Linear polarization, media_common.quotation_subject, Nuclear Theory, General Physics and Astronomy, Resonance, Polarization (waves), 01 natural sciences, Asymmetry, Nuclear physics, 0103 physical sciences, Physics::Accelerator Physics, Nuclear Experiment, 010306 general physics, Nucleon, media_common
Abstract

First measurements of double-polarization observables in ω photoproduction off the proton are presented using transverse target polarization and data from the CEBAF Large Acceptance Spectrometer (CLAS) FROST experiment at Jefferson Lab. The beam-target asymmetry F has been measured using circularly polarized, tagged photons in the energy range 1200-2700 MeV, and the beam-target asymmetries H and P have been measured using linearly polarized, tagged photons in the energy range 1200-2000 MeV. These measurements significantly increase the database on polarization observables. The results are included in two partial-wave analyses and reveal significant contributions from several nucleon (N^{*}) resonances. In particular, contributions from new N^{*} resonances listed in the Review of Particle Properties are observed, which aid in reaching the goal of mapping out the nucleon resonance spectrum.

Published
2019

3. Beam-target helicity asymmetry E in K0Λ and K0Σ0 photoproduction on the neutron

Author

P. Lenisa, M. Ungaro, D. G. Ireland, C. A. Meyer, R. Dupre, V. Crede, C.D. Bass, V. A. Nikonov, M. Battaglieri, P. Chatagnon, G. V. Fedotov, R. A. Montgomery, Ron L. Workman, R. Paremuzyan, R. A. Schumacher, C. S. Whisnant, K. P. Adhikari, A. Fradi, M. Osipenko, D. G. Jenkins, Nicholas M. Harrison, N. Markov, Martin K. Mayer, K. A. Griffioen, I. Zonta, I. J. D. MacGregor, A. Kim, H. Hakobyan, M. Khachatryan, D. Sokhan, H. S. Jo, Tim O'Connell, D. Marchand, S. Diehl, M. Bashkanov, B. McKinnon, A. I. Ostrovidov, K. Park, V. Mokeev, G. Khachatryan, L. Lanza, Eberhard Klempt, P. Collins, S. Niccolai, F. X. Girod, M. Contalbrigo, Sandra K. Johnston, P. Eugenio, T. Chetry, Volker D. Burkert, A. S. Biselli, Pawel Nadel-Turonski, M. Mirazita, J. Zhang, Rong Wang, J. W. Price, Alessandro Rizzo, S. Strauch, Iu. Skorodumina, C. Hanretty, George Davey Smith, M. Taiuti, C. Djalali, J. A. Tan, E. Golovatch, Y. G. Sharabian, M. Lowry, G. Charles, K. L. Giovanetti, I. Bedlinskiy, M. Rehfuss, K. Hicks, S. Adhikari, M. L. Kabir, M. Ehrhart, F. Sabatié, Andreas Klein, V. Laine, F. Cao, D. Adikaram, M. Guidal, W. Kim, Larry Weinstein, Z. Akbar, G. Rosner, P. Peng, C. Munoz Camacho, M. H. Wood, M. Hattawy, G. Niculescu, J. A. Fleming, I. I. Strakovsky, M. Holtrop, A. Filippi, A. D'Angelo, M. Ripani, Y. Ghandilyan, Carlos A. Salgado, B. A. Clary, A. M. Sandorfi, B. S. Ishkhanov, M. Khandaker, D. I. Sober, A. Deur, Hong Lu, Michael Paolone, D. Ho, S. Fegan, A. Celentano, R. W. Gothe, D. Heddle, Maxime Defurne, E. L. Isupov, W. Gohn, S. Boiarinov, R. De Vita, T. Kageya, L. El Fassi, N. K. Walford, R. G. Fersch, Frank Klein, P. L. Cole, Z. W. Zhao, Dustin Keller, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, Nikos Sparveris, X. Wei, K. Hafidi, E. Voutier, A. Movsisyan, Yordanka Ilieva, L. Barion, V. P. Kubarovsky, D. Riser, A. El Alaoui, Nicholas Zachariou, O. Pogorelko, K. Livingston, H. Voskanyan, D. Protopopescu, W. J. Briscoe, E. Pasyuk, D. P. Watts, H. Egiyan, A. V. Sarantsev, and S. Chandavar

Subjects
Physics, Strange quark, 010308 nuclear & particles physics, media_common.quotation_subject, Nuclear Theory, Quark model, Hyperon, 01 natural sciences, Helicity, Asymmetry, Pseudoscalar meson, Nuclear physics, 13. Climate action, Isospin, 0103 physical sciences, Neutron, Nuclear Experiment, 010306 general physics, media_common
Abstract

We report the first measurements of the E beam-target helicity asymmetry for the γn→K0Λ and K0Σ0 channels in the energy range 1.70≤W≤2.34 GeV. The CLAS system at Jefferson Lab uses a circularly polarized photon beam and a target consisting of longitudinally polarized solid molecular hydrogen deuteride with low background contamination for the measurements. The multivariate analysis method boosted decision trees is used to isolate the reactions of interest. Comparisons with predictions from the KaonMAID, SAID, and Bonn-Gatchina models are presented. These results will help separate the isospin I=0 and I=1 photocoupling transition amplitudes in pseudoscalar meson photoproduction.

Published
2018

4. Measurement of the beam asymmetry Σ and the target asymmetry T in the photoproduction of ω mesons off the proton using CLAS at Jefferson Laboratory

Author

William Brooks, George Davey Smith, R. A. Schumacher, A. El Alaoui, S. Stepanyan, J. Pierce, H. Y. Lu, P. Eugenio, G. Gavalian, I. Denisenko, N. Dashyan, Taya Chetry, M. Taiuti, A. Filippi, A. Fradi, D. P. Watts, K. A. Griffioen, Friedrich Klein, V. Crede, M. Khandaker, D. G. Meekins, Brian Raue, A. D'Angelo, A. V. Sarantsev, Yordanka Ilieva, Nicholas Zachariou, E. Pasyuk, V. Mokeev, V. Batourine, R. Paremuzyan, R. De Vita, N. Markov, L. Lanza, G. Rosner, E. Golovatch, K. Hicks, W. Kim, Sergey Kuleshov, M. Ripani, R. A. Montgomery, F. Sabatié, S. Niccolai, Carlos A. Salgado, C. D. Keith, Pawel Nadel-Turonski, D. G. Jenkins, Eberhard Klempt, B. A. Clary, J. Brock, Alessandro Rizzo, R. Dupre, M. Battaglieri, J. Zhang, C. Djalali, J. A. Tan, L. El Fassi, J. W. Price, S. Anefalos Pereira, K. Livingston, C. Hanretty, C. Carlin, M. Guidal, L. Guo, M. Ungaro, Gerard Gilfoyle, A. I. Ostrovidov, A. V. Anisovich, K. Park, G. Charles, G. Niculescu, V. A. Nikonov, G. Ciullo, J. P. Ball, B. Torayev, Y. Prok, F. X. Girod, M. E. McCracken, D. S. Carman, D. G. Ireland, M. Holtrop, K. Joo, I. Bedlinskiy, V. P. Kubarovsky, D. Riser, M. Osipenko, Andreas Klein, Nikos Sparveris, X. Wei, T. Mineeva, D. Sokhan, O. Pogorelko, S. Procureur, W. Gohn, A. Kim, Z. E. Meziani, W. Phelps, Volker D. Burkert, M. Bashkanov, A. S. Biselli, B. S. Ishkhanov, L. Elouadrhiri, K. L. Giovanetti, I. Balossino, S. Strauch, Michael Dugger, D. I. Sober, E. Voutier, I. I. Strakovsky, A. Movsisyan, B. McKinnon, Dustin Keller, S. Park, A. Deur, K. Hafidi, Iu. Skorodumina, Sylvester Joosten, S. Fegan, G. Khachatryan, P. L. Cole, Z. W. Zhao, E. Phelps, N. Gevorgyan, D. Protopopescu, W. J. Briscoe, C. Munoz Camacho, M. H. Wood, A. Celentano, R. W. Gothe, M. Contalbrigo, Z. Akbar, N. K. Walford, I. J. D. MacGregor, S. Adhikari, M. Hattawy, Martin K. Mayer, Y. G. Sharabian, C. Gleason, Barry Ritchie, P. Roy, C. A. Meyer, G. V. Fedotov, E. L. Isupov, S. Boiarinov, K. P. Adhikari, H. Hakobyan, and P. Lenisa

Subjects
Physics, Particle physics, Proton, Meson, 010308 nuclear & particles physics, Partial wave analysis, media_common.quotation_subject, Nuclear Theory, Bremsstrahlung, Observable, 7. Clean energy, 01 natural sciences, Resonance (particle physics), Asymmetry, Baryon, Nuclear physics, 13. Climate action, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, media_common
Abstract

The photoproduction of ω mesons off the proton has been studied in the reaction γp→pω using the CEBAF Large Acceptance Spectrometer (CLAS) and the frozen-spin target in Hall B at the Thomas Jefferson National Accelerator Facility. For the first time, the target asymmetry T has been measured in photoproduction from the decay ω→π+π-π0, using a transversely polarized target with energies ranging from just above the reaction threshold up to 2.8 GeV. Significant nonzero values are observed for these asymmetries, reaching about 30-40% in the third-resonance region. New measurements for the photon-beam asymmetry Σ are also presented, which agree well with previous CLAS results and extend the world database up to 2.1 GeV. These data and additional ω photoproduction observables from CLAS were included in a partial-wave analysis within the Bonn-Gatchina framework. Significant contributions from s-channel resonance production were found in addition to t-channel exchange processes.

Published
2018

5. Measurement of the helicity asymmetry E in ω→π+π−π0 photoproduction

Author

M. Contalbrigo, T. Mineeva, R. A. Schumacher, Z. Akbar, M. Khachatryan, V. Mokeev, Taya Chetry, A. V. Anisovich, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, E. Golovatch, F. Cao, P. Roy, M. Guidal, B. S. Ishkhanov, K. Hicks, C. Gleason, Iu. Skorodumina, Nikos Sparveris, X. Wei, M. Holtrop, O. Cortes, K. P. Adhikari, C. D. Keith, E. L. Isupov, M. Ripani, Barry Ritchie, E. Voutier, Nicholas Zachariou, S. Stepanyan, Laura Clark, L. Guo, H. Egiyan, S. Boiarinov, G. Khachatryan, A. Movsisyan, I. J. D. MacGregor, E. De Sanctis, G. Charles, J. Brock, Sylvester Joosten, M. Hattawy, Carlos A. Salgado, A. Celentano, R. W. Gothe, A. V. Sarantsev, S. Park, M. Osipenko, F. Sabatié, W. J. Briscoe, I. I. Strakovsky, Y. G. Sharabian, S. Niccolai, M. Ungaro, D. I. Sober, A. I. Ostrovidov, K. Park, Michael Paolone, R. Dupre, M. Battaglieri, C. Munoz Camacho, A. Filippi, G. V. Fedotov, A. Deur, K. A. Griffioen, V. Crede, D. G. Ireland, W. Phelps, Lorenzo Zana, S. Adhikari, N. Dashyan, D. Protopopescu, Alessandro Rizzo, M. Garçon, Volker D. Burkert, B. McKinnon, W. K. Brooks, D. G. Jenkins, I. Bedlinskiy, V. A. Nikonov, Brian Raue, P. Nadel-Turonski, A. Fradi, F. X. Girod, W. Kim, I. Denisenko, V. Batourine, Michael Dugger, G. Rosner, N. Markov, R. Paremuzyan, S. Strauch, Andreas Klein, K. Livingston, W. Gohn, R. De Vita, C. Carlin, Nicholas M. Harrison, S. Anefalos Pereira, L. Lanza, D. Sokhan, A. Kim, C. Djalali, C. Hanretty, R. Fersch, H. Avakian, Eberhard Klempt, J. Zhang, H. Voskanyan, E. Pasyuk, J. W. Price, George Davey Smith, V. P. Kubarovsky, D. G. Meekins, A. D'Angelo, O. Pogorelko, Frank Klein, Dustin Keller, L. El Fassi, Michael Wood, K. Hafidi, P. L. Cole, Z. W. Zhao, P. Eugenio, M. Taiuti, N. Gevorgyan, D. Heddle, G. Hollis, Hrachya Hakobyan, M. J. Amaryan, K. L. Giovanetti, and M. Khandaker

Subjects
Physics, Meson, 010308 nuclear & particles physics, Partial wave analysis, Bremsstrahlung, Resonance, Observable, 01 natural sciences, Helicity, Nuclear physics, Pomeron, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

The double-polarization observable E was studied for the reaction γp → pω using the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at the Thomas Jefferson National Accelerator Facility and the longitudinally polarized frozen-spin target (FROST). The observable was measured from the charged decay mode of the meson, ω → π+π−π0, using a circularly polarized tagged-photon beam with energies ranging from the ω threshold at 1.1 to 2.3 GeV. A partial-wave analysis within the Bonn-Gatchina framework found dominant contributions from the 3/2+ partial wave near threshold, which is identified with the subthreshold N(1720) 3/2+ nucleon resonance. To describe the entire data set, which consisted of ω differential cross sections and a large variety of polarization observables, further contributions from other nucleon resonances were found to be necessary. With respect to nonresonant mechanisms, π exchange in the t channel was found to remain small across the analyzed energy range, while Pomeron t-channel exchange gradually grew from the reaction threshold to dominate all other contributions above W ≈ 2 GeV.

Published
2017

6. Measurement of the differential and total cross sections of the γd→K0Λ(p) reaction within the resonance region

Author

H. Hakobyan, M. Taiuti, Dustin Keller, N. Compton, N. Dashyan, D. I. Glazier, R. De Vita, Michael Wood, K. Hafidi, Laura Clark, Yordanka Ilieva, X. Wei, C. E. Hyde, A. Simonyan, M. Osipenko, L. Guo, Alessandro Rizzo, S. Anefalos Pereira, K. Hicks, R. Paremuzyan, R. A. Schumacher, W. Phelps, V. P. Kubarovsky, V. Crede, A. El Alaoui, J. A. Fleming, O. Pogorelko, S. M. Hughes, P. Nadel-Turonski, G. Murdoch, R. A. Montgomery, Michael Paolone, G. Gavalian, N. K. Walford, M. Camp, G. Charles, V. Mokeev, C. Gleason, Nicholas Zachariou, E. De Sanctis, K. P. Adhikari, Nicholas M. Harrison, T. Cao, H. Avakian, H. S. Jo, F. X. Girod, N. Markov, I. J. D. MacGregor, D. Heddle, C. Hanretty, Barry Ritchie, H. Voskanyan, S. Pisano, P. Lenisa, M. Contalbrigo, Avraham Klein, D. Sokhan, F. Sabatié, H. Y. Lu, G. Rosner, M. Khachatryan, I. Stankovic, Philip L. Cole, Z. Akbar, S. Adhikari, B. McKinnon, Nikolaos Sparveris, I. Bedlinskiy, E. Munevar, W. Kim, P. L. Cole, K. Livingston, Y. Ghandilyan, I. Niculescu, Friedrich Klein, D. G. Jenkins, G. Niculescu, B. S. Ishkhanov, A. D'Angelo, Taya Chetry, R. W. Gothe, Eberhard Klempt, M. Mirazita, L. El Fassi, V. Batourine, J. Zhang, S. Stepanyan, G. Khachatryan, Brian Raue, J. W. Price, Latifa Elouadrhiri, C. A. Meyer, Sergey Kuleshov, M. Ripani, M. Ungaro, A. I. Ostrovidov, K. Park, G. V. Fedotov, F. Cao, D. G. Ireland, V. A. Nikonov, Volker D. Burkert, A. S. Biselli, W. J. Briscoe, K. Joo, C. Munoz Camacho, I. I. Strakovsky, M. Guidal, Y. G. Sharabian, G. Ciullo, Y. Prok, T. Mineeva, D. S. Carman, D. Protopopescu, A. Deur, E. Voutier, S. Niccolai, A. Movsisyan, Iu. Skorodumina, W. K. Brooks, G. D. Smith, M. Holtrop, C. E. Taylor, E. Golovatch, R. Dupre, S. Strauch, D. P. Watts, H. Egiyan, A. V. Sarantsev, M. Battaglieri, B. Torayev, K. L. Giovanetti, A. Filippi, M. Khandaker, O. Cortes, E. L. Isupov, A. Fradi, Sylvester Joosten, L. Lanza, Eugene Pasyuk, Andrea Celentano, C. Djalali, N. A. Baltzell, C. Salgado, K. A. Griffioen, A. Trivedi, and P. Eugenio

Subjects
Physics, Particle physics, 010308 nuclear & particles physics, Partial wave analysis, Quark model, Gamma ray, Bremsstrahlung, Resonance, Lambda, 01 natural sciences, Particle identification, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

We report the first measurement of differential and total cross sections for the $\ensuremath{\gamma}d\ensuremath{\rightarrow}{K}^{0}\mathrm{\ensuremath{\Lambda}}(p)$ reaction, using data from the CLAS detector at the Thomas Jefferson National Accelerator Facility. Data collected during two separate experimental runs were studied with photon-energy coverage 0.8--3.6 GeV and 0.5-- 2.6 GeV, respectively. The two measurements are consistent giving confidence in the method and determination of systematic uncertainties. The cross sections are compared with predictions from the KAON-MAID theoretical model (without kaon exchange), which deviate from the data at higher $W$ and at forward kaon angles. These data, along with previously published cross sections for ${K}^{+}\mathrm{\ensuremath{\Lambda}}$ photoproduction, provide essential constraints on the nucleon resonance spectrum. A first partial wave analysis was performed that describes the data without the introduction of new resonances.

Published
2017

7. Beam-Target Helicity Asymmetry for γ→n→→π−p in the N* Resonance Region

Author

C. Gleason, Barry Ritchie, G. V. Fedotov, K. P. Adhikari, J. Ball, M. Hattawy, D. P. Watts, Marco Ripani, H. Hakobyan, G. Rosner, S. Fegan, F. X. Girod, M. Ungaro, K. A. Griffioen, I. I. Strakovsky, K. Livingston, R. Paremuzyan, C. Djalali, X. Wei, A. V. Sarantsev, A. Deur, L. Elouadrhiri, Y. Ghandilyan, R. A. Schumacher, Nicholas M. Harrison, Gerard Gilfoyle, Z. Akbar, V. Crede, L. Lanza, D. I. Glazier, M. Osipenko, Jie Zhang, E. Pasyuk, G. Khachatryan, R. A. Montgomery, P. Lenisa, P. L. Cole, G. Ciullo, D. Sokhan, N. Markov, D. S. Carman, W. Phelps, V. P. Kubarovsky, D. Riser, P. Eugenio, L. Clark, M. Bashkanov, V. Laine, O. Pogorelko, W. J. Briscoe, F. J. Klein, S. Niccolai, R. Fersch, S. M. Hughes, B. McKinnon, Nikolaos Sparveris, A. Movsisyan, M. M. Lowry, I. Zonta, R. De Vita, N. Dashyan, H. S. Jo, C. Salgado, Avraham Klein, Ron L. Workman, F. Sabatié, I. Bedlinskiy, L. Colaneri, Andrea Celentano, C. Bass, Dustin Keller, H. Y. Lu, Yordanka Ilieva, E. Golovatch, S. Strauch, N. K. Walford, R. Dupre, G. Charles, Alfred Švarc, S. Procureur, L. El Fassi, Victor Mokeev, Z. W. Zhao, J. A. Fleming, J. W. Price, D. Ho, Michael Wood, T. Kageya, A. M. Sandorfi, Y. G. Sharabian, Taya Chetry, S. Anefalos Pereira, I. J. D. MacGregor, W. Kim, P. Collins, G. Niculescu, V. A. Nikonov, A. D'Angelo, R. W. Gothe, C. S. Whisnant, E. L. Isupov, M. Battaglieri, Ye Tian, H. Voskanyan, A. Fradi, K. Joo, K. Hicks, E. De Sanctis, V. Batourine, D. A. Jenkins, Sergey Kuleshov, D. G. Ireland, H. Jiang, C. S. Nepali, P. Peng, K. Park, D. I. Sober, Volker D. Burkert, C. Munoz Camacho, A. S. Biselli, Tim O'Connell, Eberhard Klempt, B. S. Ishkhanov, D. Adikaram, T. Mineeva, M. Guidal, L. Guo, Alessandro Rizzo, S. Joosten, G. D. Smith, M. Holtrop, D. Protopopescu, C. Hanretty, A. Kim, W. Gohn, E. Voutier, A. El Alaoui, Nicholas Zachariou, B. Torayev, M. J. Amaryan, H. Avakian, M. Contalbrigo, M. Khandaker, A. Filippi, M. Paolone, Iu. Skorodumina, and G. Murdoch

Subjects
Physics, Photon, 010308 nuclear & particles physics, General Physics and Astronomy, 7. Clean energy, 01 natural sciences, Helicity, Nuclear physics, Deuterium, Solid hydrogen, Isospin, 0103 physical sciences, Neutron, Invariant mass, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

We report the first beam-target double-polarization asymmetries in the γ þ nðpÞ → π− þ pðpÞ reaction spanning the nucleon resonance region from invariant mass W ¼ 1500 to 2300 MeV. Circularly polarized photons and longitudinally polarized deuterons in solid hydrogen deuteride (HD) have been used with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The exclusive final state has been extracted using three very different analyses that show excellent agreement, and these have been used to deduce the E polarization observable for an effective neutron target. These results have been incorporated into new partial wave analyses and have led to significant revisions for several γnN* resonance photocouplings.

Published
2017

8. Scrutinizing the evidence for N(1685)

Author

Volker D. Burkert, U. Thoma, A. V. Anisovich, A. V. Sarantsev, V. A. Nikonov, and Eberhard Klempt

Subjects
Physics, Particle physics, 010308 nuclear & particles physics, 0103 physical sciences, Parity (physics), Observable, Nuclear Experiment, 010306 general physics, 01 natural sciences
Abstract

The helicity-dependent observable $E$ for the reaction $\ensuremath{\gamma}d\ensuremath{\rightarrow}\ensuremath{\eta}n(p)$ with a spectator proton was recently measured by the A2 Collaboration at MAMI in Mainz. The data were interpreted as further evidence for a narrow resonance with spin and parity ${J}^{P}=1/{2}^{+}$ $({P}_{11}$ wave). However, a full partial-wave analysis without any narrow resonance leads to an excellent description of the data. Imposing a narrow resonance with the properties suggested by the A2 Collaboration leads to a significant deterioration of the fit quality: there is no need for a narrow resonance.

Published
2017

9. Erratum: Modification of theω-Meson Lifetime in Nuclear Matter [Phys. Rev. Lett.100, 192302 (2008)]

Author

M. Kotulla, A. Ehmanns, I. Jaegle, Ulrich Mosel, Gisela Anton, V. Metag, V. Crede, S. Hoeffgen, I. Fabry, R. W. Gothe, Yu. A. Beloglazov, T. Mertens, J. C. S. Bacelar, M. Konrad, S. Shende, J. G. Messchendorp, D. E. Bayadilov, E. Gutz, H. Dutz, J. Lotz, A. B. Gridnev, Mariana Nanova, J. Hoessl, O. Bartholomy, Michael Fuchs, D. Trnka, J. Langheinrich, R. Gregor, I. V. Lopatin, D. Elsner, R. W. Novotny, Ph. Hoffmeister, R. Castelijns, R. Ewald, K. Essig, S. Schadmand, S. Lugert, Eberhard Klempt, P. Muehlich, J. Junkersfeld, H. Loehner, Fritz Klein, I. Horn, D. Menze, B. Kopf, Ch. Funke, B. Krusche, H. Kalinowsky, R. Bogendoerfer, and Frank Klein

Subjects
Nuclear physics, Physics, Particle physics, Meson production, Meson, General Physics and Astronomy, Nuclear matter, Omega
Published
2015

10. Three-Body Nature ofN*andΔ*Resonances from Sequential Decay Chains

Author

Frank Klein, V. Sokhoyan, A. Wilson, E. Gutz, M. Pfeiffer, S. Shende, J. Junkersfeld, J. G. Messchendorp, R. Beck, D. V. Novinski, Ch. Schmidt, M. Kotulla, D. Walther, V. A. Nikonov, R. Castelijns, Matthew Lang, Wolfgang Hillert, A. Thiel, A. V. Anisovich, I. Horn, S. Lugert, H. Kalinowsky, Cbelsa, U. Thoma, Eberhard Klempt, B. Bantes, V. Kleber, D. Elsner, Volker Metag, H. van Pee, R. Gregor, R. Varma, T. Mertens, Friedrich Klein, Herbert Löhner, R. W. Novotny, Yu. A. Beloglazov, B. Krusche, A. Roy, A. V. Sarantsev, Ph. Hoffmeister, O. Bartholomy, L. M. Pant, H. Dutz, S. Kammer, Bernard Metsch, Frank Frommberger, D. Piontek, Ch. Wendel, Ch. Funke, I. V. Lopatin, V. V. Sumachev, H. Schmieden, V. Crede, D. E. Bayadilov, A. B. Gridnev, Mariana Nanova, A. Süle, I. Jaegle, M. Ostrick, D. Trnka, J. C. S. Bacelar, R. Ewald, T. Szczepanek, and M. Fuchs

Subjects
Physics, Partial wave analysis, Nuclear Theory, General Physics and Astronomy, Dalitz plot, Delta baryon, Particle decay, Pion, Isobar, High Energy Physics::Experiment, Decay chain, Atomic physics, Nuclear Experiment, Nucleon
Abstract

The N pi(0)pi(0) decays of positive-parity N* and Delta* resonances at about 2 GeV are studied at ELSA by photoproduction of two neutral pions off protons. The data reveal clear evidence for several intermediate resonances: Delta(1232), N(1520)3/2(-), and N(1680)5/2(+), with spin parities J(P) = 3/2(+), 3/2(-), and 5/2(+). The partial wave analysis (within the Bonn-Gatchina approach) identifies N(1440)1/2(+) and the N(pi pi)s (wave) (abbreviated as N sigma here) as further isobars and assigns the final states to the formation of nucleon and Delta resonances and to nonresonant contributions. We observe the know Delta(1232)pi decays of Delta(1910)1/2(+), Delta(1920)3/2(+), Delta(1905)5/2(+), Delta(1950)7/2(+), and of the corresponding spin-parity series in the nucleon sector, N(1880)1/2(+), N(1900)3/2(+), N(2000)5/2(+), and N(1990)7/2(+). For the nucleon resonances, these decay modes are reported here for the first time. Further new decay modes proceed via N(1440)1/2(pi)(+), N(1520)3/2(pi)(-) , N(1680)5/2(pi)(+), and N sigma. The latter decay modes are observed in the decay of N* resonances and at most weakly in Delta(*) decays. It is argued that these decay modes provide evidence for a 3-quark nature of N* resonances rather than a quark-diquark structure.

Published
2015

11. N(1520)3/2−Helicity Amplitudes from an Energy-Independent Multipole Analysis Based on New Polarization Data on Photoproduction of Neutral Pions

Author

Ph. Thämer, Ch. Honisch, Ch. Schmidt, J. Hannappel, A. V. Anisovich, V. A. Nikonov, A. V. Sarantsev, H. Schmieden, Alastair J. Wilson, T. C. Jude, Ulrich Wiedner, D. E. Bayadilov, Lilian Witthauer, A. B. Gridnev, Mariana Nanova, M. Kube, A. Thiel, A. Käser, U. Thoma, K. Makonyi, Francesco Messi, K.-Th. Brinkmann, M. Grüner, Ch. Hammann, Matthew Lang, K. Fornet-Ponse, H. van Pee, K. Koop, M. Becker, Yu. A. Beloglazov, S. Böse, H. Kalinowsky, G. Reicherz, A. Berlin, E. Gutz, D. V. Novinski, Friedrich Klein, F. Kalischewski, A. Winnebeck, P. Klassen, M. Urban, T. Rostomyan, M. Gottschall, D. Elsner, D. Walther, V. Sokhoyan, W. Meyer, V. Metag, T. Seifen, R. W. Novotny, Ph. Hoffmeister, Ch. Funke, B. Krusche, Friedrich, Eberhard Klempt, B. Roth, M. Bichow, Reinhard Beck, Wolfgang Hillert, M. Dieterle, Y. Wunderlich, Ch. Wendel, Frank Frommberger, D. Piontek, I. V. Lopatin, H. Dutz, H. Eberhardt, V. Crede, I. Keshelashvili, Jörg H. Müller, Jens Hartmann, D. Kaiser, R. Schmitz, C. Rosenbaum, O. Jahn, V. Hannen, and J. Herick

Subjects
Physics, 010308 nuclear & particles physics, Linear polarization, Partial wave analysis, General Physics and Astronomy, Electron, Polarization (waves), 01 natural sciences, Helicity, Nuclear physics, Amplitude, Pion, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Multipole expansion
Abstract

New data on the polarization observables T, P, and H for the reaction γp→pπ0 are reported. The results are extracted from azimuthal asymmetries when a transversely polarized butanol target and a linearly polarized photon beam are used. The data were taken at the Bonn electron stretcher accelerator ELSA using the CBELSA/TAPS detector. These and earlier data are used to perform a truncated energy-independent partial wave analysis in sliced-energy bins. This energy-independent analysis is compared to the results from energy-dependent partial wave analyses.

Published
2014

12. First Measurement of the Helicity Asymmetry forγp→pπ0in the Resonance Region

Author

R. W. Novotny, Ph. Hoffmeister, K. Makonyi, A. V. Anisovich, K.-Th. Brinkmann, K. Fornet-Ponse, H. van Pee, K. Koop, Frank Klein, M. Urban, V. Crede, Matthew Lang, Friedrich, A. Wilson, V. Sokhoyan, Yasser Maghrbi, H. Dutz, R. Schmitz, R. Ewald, D. Piontek, R. Beck, W. Meyer, G. Reicherz, H. Schmieden, D. E. Bayadilov, H. Eberhardt, I. V. Lopatin, T. Seifen, H. Kalinowsky, A. B. Gridnev, Mariana Nanova, J. Hannappel, D. Kaiser, I. Jaegle, J. Mueller, Ulrich Wiedner, U. Thoma, M. Gruener, Frank Frommberger, Jens Hartmann, Wolfgang Hillert, V. Metag, M. Gottschall, T. Rostomyan, E. Gutz, I. Keshelashvili, M. Bichow, A. V. Sarantsev, D. Walther, B. Bantes, S. Boese, V. A. Nikonov, A. Thiel, Eberhard Klempt, Ch. Hammann, A. Winnebeck, M. Kube, Ch. Honisch, Ch. Schmidt, S. Kammer, F. Dietz, Th. Challand, Ch. Funke, B. Krusche, Ch. Wendel, Schaepe, and D. Elsner

Subjects
Physics, Photon, 010308 nuclear & particles physics, media_common.quotation_subject, Nuclear Theory, Solid angle, General Physics and Astronomy, Resonance, 01 natural sciences, Asymmetry, Helicity, Nuclear physics, Cross section (physics), Amplitude, Pion, 0103 physical sciences, Nuclear Experiment, 010306 general physics, media_common
Abstract

The first measurement of the helicity dependence of the photoproduction cross section of single neutral pions off protons is reported for photon energies from 600 to 2300 MeV, covering nearly the full solid angle. The data are compared to predictions from the SAID, MAID, and BnGa partial wave analyses. Strikingly large differences between data and predictions are observed, which are traced to differences in the helicity amplitudes of well-known and established resonances. Precise values for the helicity amplitudes of several resonances are reported.

Published
2014

13. p¯pannihilation at rest intoKLK±π∓

Author

D. Walther, F. H. Heinsius, C. Völcker, M. A. Faessler, R.P. Haddock, U. Strohbusch, C. Pietra, J. Lüdemann, Marcel Kunze, P. Schmidt, K. Braune, W. Dünnweber, R. McCrady, C.J. Batty, H. Stöck, U. Wiedner, Herbert Koch, Č. Zupančič, A. Ehmanns, Claude Amsler, C.A. Baker, R. Landua, M. Ratajczak, U. Kurilla, A. Berdoz, R. Ouared, Michael Doser, M. Benayoun, B. Pick, S. M. Spanier, Pàl Hidas, P. Blüm, Kenneth M. Crowe, U. Thoma, M. Tischhäuser, Farid Ould-Saada, C. A. Meyer, C. Kolo, M. Suffert, R. Seibert, W. Roethel, M. Lakata, K. Beuchert, D. Jamnik, D. Engelhardt, O. Cramer, A. Abele, J. Adomeit, S. Wallis, K. Peters, H. Kalinowsky, J. Meier, S. Bischoff, P. Kammel, K. Wittmack, P. Giarritta, C. Holtzhaußen, J. Kisiel, S. Resag, T. Degener, M. Herz, A. Herbstrith, T. Case, H. Matthäy, C. N. Pinder, S. v. Dombrowski, Eberhard Klempt, L. Montanet, M. Heinzelmann, B. M. Barnett, V. Crede, B. Kämmle, C. Regenfus, Nigel Hessey, C. Strassburger, and N. Djaoshvili

Subjects
Physics, Nuclear and High Energy Physics, Crystallography, Annihilation, Branching fraction, Partial wave analysis, Pi, Dalitz plot, K matrix
Abstract

We present a measurement and partial wave analysis of the final state ${K}_{L}{K}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{\ensuremath{\mp}}$ of $\overline{p}p$ annihilation at rest in liquid hydrogen. This reaction is important for the study of the $\overline{K}K$ decay mode of scalar resonances, in particular, the isovectors ${a}_{0}(980)$ and ${a}_{0}(1450).$ The determination of the ${a}_{0}(1450)$ production also fixes the $\overline{K}K$ coupling of the isoscalar ${f}_{0}(1500)$ which is discussed as a glueball. We find $B(\overline{p}\stackrel{\ensuremath{\rightarrow}}{p}{a}_{0}(1450)\ensuremath{\pi}{;a}_{0}(1450)\ensuremath{\rightarrow}\overline{K}K)=(8.88\ifmmode\pm\else\textpm\fi{}1.68)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ and hence $B(\overline{p}\stackrel{\ensuremath{\rightarrow}}{p}{f}_{0}(1500)\ensuremath{\pi}{;f}_{0}(1500)\ensuremath{\rightarrow}\overline{K}K)=(4.52\ifmmode\pm\else\textpm\fi{}0.36)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}.$ The mass and width of ${a}_{0}(1450)$ are $m=1480\ifmmode\pm\else\textpm\fi{}30\mathrm{MeV}{/c}^{2}$ and $\ensuremath{\Gamma}=265\ifmmode\pm\else\textpm\fi{}15\mathrm{MeV}{/c}^{2},$ respectively. For ${a}_{0}(980)$ we determine the relative ratio $B(\overline{p}\stackrel{\ensuremath{\rightarrow}}{p}{a}_{0}\ensuremath{\pi}{;a}_{0}\ensuremath{\rightarrow}\overline{K}K)/B(\overline{p}\stackrel{\ensuremath{\rightarrow}}{p}{a}_{0}\ensuremath{\pi}{;a}_{0}\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\eta})$ =0.23\ifmmode\pm\else\textpm\fi{}0.05 and its relative coupling, $\overline{K}K$ to \ensuremath{\pi}\ensuremath{\eta}, is $1.03\ifmmode\pm\else\textpm\fi{}0.14.$

Published
1998

14. Thielet al.Reply

Author

G. Reicherz, F. Kalischewski, Yu. A. Beloglazov, V. Metag, A. V. Sarantsev, J. Hannappel, U. Thoma, H. Schmieden, D. E. Bayadilov, James Mueller, W. Meyer, Mariana Nanova, Eberhard Klempt, V. Kleber, Wolfgang Hillert, M. Bichow, Matthew Lang, I. Juergensen, D. Walther, A. V. Anisovich, D. Kaiser, D. Piontek, M. Gottschall, I. V. Lopatin, A. Thiel, U. Wiedner, Y. Wunderlich, S. Boese, H. Kalinowsky, D. Elsner, Jens Hartmann, V. A. Nikonov, K. Fornet-Ponse, R. W. Novotny, Ph. Hoffmeister, I. Keshelashvili, R. Beck, E. Gutz, Ch. Honisch, Ch. Schmidt, H. vanPee, Ch. Hammann, B. Bantes, V. Sokhoyan, B. Krusche, Ch. Wendel, P. Drexler, V. V. Sumachev, S. Kammer, A. Winnebeck, F. Dietz, Th. Challand, Ch. Funke, Frank Frommberger, Frank Klein, Friedrich, K. Makonyi, K.-Th. Brinkmann, T. Seifen, I. Jaegle, M. Gruener, Yasser Maghrbi, H. Dutz, H. Eberhardt, V. Crede, R. Ewald, and Alastair J. Wilson

Subjects
Physics, 010308 nuclear & particles physics, Quantum electrodynamics, 0103 physical sciences, General Physics and Astronomy, 010306 general physics, Polarization (waves), Nucleon, 01 natural sciences
Published
2013

15. In-mediumωmass from theγ+Nb→π0γ+Xreaction

Author

V. Metag, M. Ostrick, M. Kotulla, Ch. Schmidt, A. Ehmanns, V. Crede, M. Pfeiffer, D. Elsner, R. Ewald, R. Bogendorfer, R. W. Novotny, Ph. Hoffmeister, Yu. A. Beloglazov, R. Gregor, T. Szczepanek, Friedrich Klein, B. Schoch, J. C. S. Bacelar, H. Schmieden, D. E. Bayadilov, I. Fabry, A. Radkov, A. B. Gridnev, Mariana Nanova, G. Suft, S. Shende, Michael Fuchs, D. Trnka, J. Langheinrich, J. Lotz, O. Bartholomy, H. Dutz, U. Thoma, Frank Klein, J. Hossl, S. Schadmand, R. Varma, I. V. Lopatin, R. W. Gothe, D. Walther, Ch. Weinheimer, H. van Pee, E. Gutz, J. Junkersfeld, J. G. Messchendorp, T. Mertens, Herbert Löhner, C. Morales, Lalit Mohan Pant, M. Konrad, B. Kopf, I. Jaegle, Gisela Anton, Ch. Funke, I. Horn, S. Lugert, Eberhard Klempt, S. Höffgen, B. Krusche, R. Castelijns, K. Essig, A. Süle, Ankhi Roy, D. Menze, Ch. Wendel, V. V. Sumachev, and H. Kalinowsky

Subjects
Absolute magnitude, Physics, Nuclear and High Energy Physics, Particle physics, Photon, Meson, Electron, Sensitivity (control systems), Nuclear Experiment, Nuclear matter, Omega, Line (formation)
Abstract

Data on the photoproduction of $\ensuremath{\omega}$ mesons on nuclei have been reanalyzed in a search for in-medium modifications. The data were taken with the crystal barrel (CB)/two-arm photon spectrometer (TAPS) detector system at the ELectron Stretcher Anlage (ELSA) accelerator facility in Bonn. First results from the analysis of the data set were published by Trnka et al. [Phys. Rev. Lett. 94, 192303 (2005)], claiming a lowering of the $\ensuremath{\omega}$ mass in the nuclear medium by 14$%$ at normal nuclear matter density. The extracted $\ensuremath{\omega}$ line shape was found to be sensitive to the background subtraction. For this reason a reanalysis of the same data set has been initiated, and a new method has been developed to reduce the background and to determine the shape and absolute magnitude of the background directly from the data. Details of the reanalysis and of the background determination are described. The $\ensuremath{\omega}$ signal on the Nb target, extracted in the reanalysis, does not show a deviation from the corresponding line shape on a ${\mathrm{LH}}_{2}$ target, measured as reference. The earlier claim of an in-medium mass shift is thus not confirmed. The sensitivity of the $\ensuremath{\omega}$ line shape to different in-medium modification scenarios is discussed.

Published
2010

16. Measurement of the beam asymmetryΣin the forward direction forγ⃗p→pπ0

Author

O. Bartholomy, V. A. Nikonov, S. Lugert, Eberhard Klempt, H. Schmieden, D. E. Bayadilov, T. Mertens, E. Gutz, A. B. Gridnev, Mariana Nanova, Herbert Löhner, D. Elsner, R. Castelijns, Yu. A. Beloglazov, H. van Pee, H. Kalinowsky, J. C. S. Bacelar, A. V. Sarantsev, N. Sparks, R. W. Novotny, Ph. Hoffmeister, B. Krusche, D. Menze, Friedrich Klein, S. Kammer, I. Jaegle, C. Funke, Ch. Schmidt, Ch. Wendel, B. Schoch, V. V. Sumachev, L. M. Pant, A. Roy, R. Bantes, S. Shende, D. V. Novinski, V. Sokhoyan, Volker Metag, R. Gregor, A. V. Anisovich, U. Thoma, J. G. Messchendorp, D. Walther, S. Schadmand, J. Junkersfeld, R. Ewald, I. V. Lopatin, Wolfgang Hillert, R. Beck, D. Trnka, M. Kotulla, T. Szczepanek, R. Varma, A. Süle, M. Ostrick, V. Crede, Frank Klein, A. Wilson, M. Pfeiffer, and Frank Frommberger

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Photon, Meson, media_common.quotation_subject, Hadron, Sigma, Elementary particle, Asymmetry, Nuclear physics, Pion, High Energy Physics::Experiment, Nuclear Experiment, Lepton, media_common
Abstract

Photoproduction of neutral pions has been studied with the CBELSA/TAPS detector for photon energies between 0.92 and 1.68 GeV at the electron stretcher accelerator ELSA. The beam asymmetry Sigma has been extracted for 115 degrees > theta(c.m.) > 155 degrees of the pi(0) meson and for theta(c.m.) > 60 degrees. The new beam-asymmetry data cover the very forward region, which extend previously published data for the same reaction by our collaboration and improve the world database for photon energies above 1.5 GeV. The angular dependence of Sigma shows overall good agreement with the SAID parametrization.

Published
2010

17. Beam asymmetries in near-thresholdωphotoproduction off the proton

Author

V. Sokhoyan, Matthew Lang, M. Pfeiffer, D. Walther, A. Ehmanns, J. Junkersfeld, R. Varma, Ch. Weinheimer, S. Shende, Friedrich Klein, M. Ostrick, H. Kalinowsky, H. Dutz, Frank Klein, A. Roy, R. Beck, D. Elsner, D. Menze, V. Metag, E. Gutz, V. Crede, Ph. Hoffmeister, H. Schmieden, I. Jaegle, D. E. Bayadilov, S. Kammer, A. B. Gridnev, H. van Pee, Mariana Nanova, Ch. Wendel, V. Kleber, Ch. Funke, Yu. A. Beloglazov, R. Castelijns, A. Suele, V. V. Sumachev, A. V. Sarantsev, O. Bartholomy, M. Kotulla, K. Essig, M. Konrad, D. Trnka, R. Novotny, S. Hoeffgen, I. V. Lopatin, T. Mertens, A. V. Anisovich, U. Thoma, Herbert Löhner, B. Bantes, C. Morales, B. Schoch, A. Radkov, J. G. Messchendorp, I. Fabry, J. C. S. Bacelar, R. Gregor, R. Ewald, T. Szczepanek, M. Fuchs, V. A. Nikonov, I. Horn, S. Lugert, Eberhard Klempt, Ch. Schmidt, J. Lotz, D. V. Novinski, B. Krusche, L. M. Pant, Research unit Nuclear & Hadron Physics, and Publica

Subjects
TAPS, Physics, Nuclear and High Energy Physics, Photon, Proton, Meson, media_common.quotation_subject, photon, Nuclear Theory, Bremsstrahlung, Resonance, PHOTONS, MESONS, ETA, Omega, Asymmetry, Nuclear physics, Pion, SPECTROMETER, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, media_common
Abstract

The photoproduction of {omega} mesons off protons has been studied at the Bonn ELSA accelerator from threshold to E{sub {gamma}}=1700 MeV. Linearly polarized beams were produced via coherent bremsstrahlung. Large photon asymmetries in excess of 50% were obtained. For the first time the pion asymmetries associated with the {omega}{yields}{pi}{sup 0}{gamma} decay were measured and found close to zero. The asymmetries indicate s-channel resonance formation on top of t-channel exchange processes.

Published
2008

18. Evidence for a Parity DoubletΔ(1920)P33andΔ(1940)D33fromγp→pπ0η

Author

R. Castelijns, D. Menze, J. Junkersfeld, J. Ernst, A. Ehmanns, B. Krusche, Sumachev, J. Hossl, M. Konrad, Herbert Löhner, Crede, B. Kopf, A. V. Anisovich, H. Schmieden, E. Gutz, O. Bartholomy, A. B. Gridnev, D. Walther, M. Ostrick, Metag, J. Lotz, D. V. Novinski, R. Bantes, Frank Klein, Gisela Anton, U. Thoma, V. A. Nikonov, R. W. Gothe, C. Funke, H. Flemming, B. Schoch, Yu. A. Beloglazov, A. V. Sarantsev, H. Kalinowsky, G. Suft, I. V. Lopatin, Messchendorp J, I. Horn, Eberhard Klempt, S. Höffgen, H. Matthäy, van Pee H, C.-H. Weinheimer, R. Beck, I. Fabry, Herbert Koch, R. Bogendorfer, T. Szczepanek, M. Fuchs, J. Langheinrich, A. Fosel, and Ch. Schmidt

Subjects
Delta, Quantum chromodynamics, Physics, Nuclear physics, Particle physics, Total angular momentum quantum number, Partial wave analysis, Quark model, Pi, General Physics and Astronomy, Parity (physics), Nuclear Experiment, Delta baryon
Abstract

Evidence is reported for the existence of a parity doublet of Delta resonances with total angular momentum J=3/2 from photoproduction of the p pi(0)eta final state. The two parity partners Delta(1920)P-33 and Delta(1940)D-33 make significant contributions to the reaction. Cascades of resonances into Delta(1232)eta, N(1535)pi, and Na-0(980) are clearly observed.

Published
2008

19. Observation of In-Medium Modifications of theωMeson

Author

V. Crede, V. Metag, I. Fabry, Yu. A. Beloglazov, Lalit Mohan Pant, R. W. Gothe, S. Lugert, H. Dutz, J. Hossl, Eberhard Klempt, S. Höffgen, R. Varma, R. Castelijns, Fritz Klein, I. Horn, M. Ostrick, G. Suft, S. Shende, I. Jaegle, M. Kotulla, T. Mertens, R. Gregor, S. Schadmand, Herbert Löhner, A. Roy, Gisela Anton, O. Bartholomy, Ch. Schmidt, C. Morales, J. Lotz, D. Trnka, J. Langheinrich, H. Kalinowsky, D. Walther, T. Szczepanek, Frank Klein, K. Essig, A. Süle, E. Gutz, B. Kopf, B. Krusche, A. Radkov, A. Ehmanns, H. van Pee, M. Pfeiffer, Ch. Funke, D. Menze, D. Elsner, M. Konrad, H. Schmieden, D. E. Bayadilov, Ch. Wendel, A. B. Gridnev, Mariana Nanova, V. V. Sumachev, U. Thoma, R. W. Novotny, Ph. Hoffmeister, J. C. S. Bacelar, B. Schoch, J. Junkersfeld, R. Ewald, R. Bogendorfer, J. G. Messchendorp, Michael Fuchs, I. V. Lopatin, and Ch. Weinheimer

Subjects
Physics, Particle physics, Meson, Nuclear Theory, Hadron, General Physics and Astronomy, Omega baryon, Omega, Baryon, Nuclear physics, Particle decay, Pion, High Energy Physics::Experiment, Nuclear Experiment, Nuclear density
Abstract

The photoproduction of omega mesons on nuclei has been investigated using the Crystal Barrel/TAPS experiment at the ELSA tagged photon facility in Bonn. The aim is to study possible in-medium modifications of the omega meson via the reaction gamma+A

Published
2005

20. Neutral-PionPhotoproduction off Protons in the Energy Range0.3 GeV<Eγ<3 GeV

Author

H. van Pee, M. Konrad, R. Bantes, Gisela Anton, H. Flemming, R. Joosten, M. Ostrick, Herbert Löhner, J. Langheinrich, D. V. Novinski, H. Kalinowsky, Ch. Weinheimer, G. Suft, R. Castelijns, E. Gutz, T. Szczepanek, J. Hossl, R. W. Gothe, A. Radkov, Yu. A. Beloglazov, D. Menze, A. Ehmanns, A. V. Sarantsev, V. Crede, H. Matthäy, B. Krusche, J. Reinnarth, J. Ernst, S. Schadmand, H. Freiesleben, B. Schoch, Frank Klein, C. Morales, A. V. Anisovich, V. V. Sumachev, U. Thoma, R. Bogendorfer, Michael Fuchs, J. Lotz, I. V. Lopatin, H. Schmieden, J. Junkersfeld, J. G. Messchendorp, A. B. Gridnev, D. Walther, I. Fabry, B. Kopf, Herbert Koch, A. Fosel, Ch. Schmidt, Ch. Funke, O. Bartholomy, I. Horn, Eberhard Klempt, and S. Höffgen

Subjects
Nuclear physics, Physics, Range (particle radiation), Particle physics, Pion, Photon, Proton, Partial wave analysis, Solid angle, General Physics and Astronomy, Resonance, Intermediate state
Abstract

Single pi(0) photoproduction has been studied with the CB-ELSA experiment at Bonn using tagged photon energies between 0.3 and 3.0 GeV. The experimental setup covers a very large solid angle of similar to98% of 4pi. Differential cross sections dsigma/dOmega have been measured. Complicated structures in the angular distributions indicate a variety of different resonances being produced in the s channel intermediate state gammap-->N(*)(Delta(*))-->ppi(0). A combined analysis including the data presented in this letter along with other data sets reveals contributions from known resonances and evidence for a new resonance N(2070)D(15).

Published
2005

21. PhotoproductionofηMesonsoff Protons for0.75 GeV<Eγ<3 GeV

Author

H. Flemming, M. Konrad, V. Crede, Gisela Anton, B. Kopf, D. V. Novinski, C. Morales, D. Walther, H. van Pee, U. Thoma, H. Schmieden, Ch. Funke, A. B. Gridnev, H. Kalinowsky, A. V. Anisovich, J. Junkersfeld, R. Castelijns, D. Menze, R. Joosten, A. Fosel, Ch. Schmidt, J. Langheinrich, E. Gutz, R. Bantes, S. Schadmand, A. Radkov, O. Bartholomy, M. Ostrick, A. Ehmanns, H. Matthäy, I. Fabry, Herbert Koch, J. G. Messchendorp, Frank Klein, V. V. Sumachev, Yu. A. Beloglazov, A. V. Sarantsev, J. Hosl, B. Krusche, J. Reinnarth, B. Schoch, Michael Fuchs, R. Bogendorfer, T. Szczepanek, Herbert Löhner, I. V. Lopatin, G. Suft, Ch. Weinheimer, I. Horn, Eberhard Klempt, S. Höffgen, J. Ernst, H. Freiesleben, J. Lotz, and R. W. Gothe

Subjects
Physics, Particle physics, Range (particle radiation), Photon, Meson production, Proton, Meson, Astrophysics::High Energy Astrophysical Phenomena, General Physics and Astronomy, Resonance, Nuclear physics, Angular distribution, High Energy Physics::Experiment, Nuclear Experiment, Nucleon
Abstract

Total and differential cross sections for the reaction p(gamma,eta)p have been measured for photon energies in the range from 750 MeV to 3 GeV. The low-energy data are dominated by the S-11 wave which has two poles in the energy region below 2 GeV. Eleven nucleon resonances are observed in their decay into peta. At medium energies we find evidence for a new resonance N(2070)D-15 with (M,Gamma)=(2068+/-22, 295+/-40) MeV. At gamma energies above 1.5 GeV, a strong peak in the forward direction develops, signaling the exchange of vector mesons in the t channel.

Published
2005

22. Mass formula for baryon resonances

Author

Eberhard Klempt

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Angular momentum, High Energy Physics::Phenomenology, Nuclear Theory, Quark model, FOS: Physical sciences, High Energy Physics - Experiment, Baryon, Mass formula, High Energy Physics - Experiment (hep-ex), Total angular momentum quantum number, Orbital motion, Angular momentum coupling, Nuclear Experiment, Nucleon
Abstract

Light-baryon resonances with u,d, and s quarks only can be classified using the non-relativistic quark model. When we assign to baryon resonances with total angular momenta J intrinsic orbital angular momenta L and spin S we make the following observations: plotting the squared masses of the light-baryon resonances against these intrinsic orbital angular momenta L, Delta's with even and odd parity can be described by the same Regge trajectory. For a given L, nucleon resonances with spin S=3/2 are approximately degenerate in mass with Delta resonances of same total orbital momentum L. To which total angular momentum L and S couple has no significant impact on the baryon mass. Nucleons with spin 1/2 are shifted in mass; the shift is - in units of squared masses - proportional to the component in the wave function which is antisymmetric in spin and flavor. Sequential resonances in the same partial wave are separated in mass square by the same spacing as observed in orbital angular momentum excitations. Based on these observations, a new baryon mass formula is proposed which reproduces nearly all known baryon masses., Comment: 4 pages, 1 figure

Published
2002

23. Comment on 'Protonium annihilation intoπ0π0at rest in a liquid hydrogen target'

Author

Pàl Hidas, W. Dünnweber, V. Crede, M. A. Faessler, R.P. Haddock, A. V. Sarantsev, D. Walther, F. H. Heinsius, Stefan M Spanier, R. Landua, Eberhard Klempt, M. Heinzelmann, C.J. Batty, B.S. Zou, S. Wallis-Plachner, M. Suffert, B. Pick, H. Kalinowsky, K. Wittmack, T. Case, I. Uman, H. Matthäy, J. Kisiel, C.A. Baker, W. Roethel, F. Meyer-Wildhagen, N.P. Hessey, U. Thoma, K. Braune, R. Ouared, M. Ratajczak, U. Wiedner, C. Regenfus, U. Kurilla, M. Benayoun, Kenneth M. Crowe, Claude Amsler, P. Kammel, J. Reinnarth, B.M. Barnett, U. Strohbusch, P. Blüm, Marcel Kunze, J. S. Suh, D.V. Bugg, C. A. Meyer, Herbert Koch, Michael Doser, K. Peters, D. Jamnik, and D. Engelhardt

Subjects
Nuclear physics, Rest (physics), Physics, Nuclear and High Energy Physics, Annihilation, 010308 nuclear & particles physics, Protonium, 0103 physical sciences, Atomic physics, 010306 general physics, 01 natural sciences, Liquid hydrogen
Published
2002

24. New analysis of the radiative decayω→ηγin proton-antiproton annihilation at rest

Author

C. Kolo, C.A. Baker, Kenneth M. Crowe, J.S. Suh, B.S. Zou, H. Kalinowsky, J. Meier, W. Roethel, F. H. Heinsius, K. Peters, C. Völcker, S. Bischoff, U. Wiedner, C. Straßburger, D. Jamnik, M. Ratajczak, D. Engelhardt, R. Landua, Marcel Kunze, R. Ouared, U. Kurilla, A. Abele, S. Wallis-Plachner, C.J. Batty, B. M. Barnett, B. Pick, M. Suffert, R. Seibert, M. Lakata, I. Uman, M. A. Faessler, T. Degener, R.P. Haddock, P. Kammel, A. Herbstrith, Pàl Hidas, M. Herz, D. Walther, T. Case, H. Matthäy, K. Wittmack, J. Kisiel, U. Thoma, C. Hodd, H. Stöck, C. Holtzhaußen, K. Braune, U. Strohbusch, W. Dünnweber, R. McCrady, J. Adomeit, Michael Doser, Nigel Hessey, M. Tischhäuser, P. Blüm, D.V. Bugg, Herbert Koch, Eberhard Klempt, A. Berdoz, and C. A. Meyer

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Proton, Antiproton, Branching fraction, High Energy Physics::Phenomenology, Radiative transfer, Radiative decay, Degree of coherence, Omega
Abstract

We report on a measurement of the branching ratio of the rare decay $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\omega}}\ensuremath{\eta}\ensuremath{\gamma}$ relative to the well known decay $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\omega}}{\ensuremath{\pi}}^{0}\ensuremath{\gamma}.$ The \ensuremath{\omega}'s are produced in $p\overline{p}\ensuremath{\rightarrow}\ensuremath{\eta}\ensuremath{\omega}$ and $p\overline{p}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}\ensuremath{\omega}.$ Eigenstate mixing and interference effects of the \ensuremath{\omega} and ${\ensuremath{\rho}}^{0}$ are taken into account, as well as coherent interference with the background. We find evidence for the non-resonant annihilation channel $B(p\overline{p}\ensuremath{\rightarrow}\ensuremath{\eta}\ensuremath{\eta}\ensuremath{\gamma})=(3.5\ifmmode\pm\else\textpm\fi{}1.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ and limit the value of $B(\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\omega}}\ensuremath{\eta}\ensuremath{\gamma})$ to the range of $(0.7\mathrm{to}5.5)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ depending on the degree of coherence with the background.

Published
2000

25. Observability of the sign of wave functions

Author

Eberhard Klempt

Subjects
Quantum phase transition, Physics, Quantum discord, Quantum state, Quantum mechanics, Quantum electrodynamics, Quantum process, Quantum system, Quantum phases, Wave function collapse, Wave function
Abstract

A change of the phase factor of -1 in the wave function of a molecular quantum system leads to observable consequences in transition probabilities between molecular quantum states in accordance with quantum-mechanical calculations.

Published
1976

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