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1. The role of water in space weathering of silicate surfaces

Author

Murri, M, Capitani, G, Fasoli, M, Monguzzi, A, Calloni, A, Bussetti, G, Malaspina, N, Campione, M, Murri, M, Capitani, G, Fasoli, M, Monguzzi, A, Calloni, A, Bussetti, G, Malaspina, N, and Campione, M

Subjects
space weathering, olivine, pulsed laser ablation, nanoparticles
Published
2022

3. MICROWAVE-ASSISTED BRUCITE AND TALC REACTIONS WITH CO2 AS A PROXY FOR CARBON CAPTURE AND STORAGE BY SERPENTINE

Author

Corti, M, Maroni, P, Militello GM, Yivlialin, R, Campione, M, Lucotti, A, Bussetti, G, Capitani, G, Cavallo, A, Malaspina, N, Corti, M, Maroni, P, Militello, G, Yivlialin, R, Campione, M, Lucotti, A, Bussetti, G, Capitani, G, Cavallo, A, and Malaspina, N

Subjects
Antigorite, Carbon Capture and Storage, Mineral Carbonation, GEO/07 - PETROLOGIA E PETROGRAFIA, FIS/01 - FISICA SPERIMENTALE, CHIM/12 - CHIMICA DELL'AMBIENTE E DEI BENI CULTURALI, GEO/06 - MINERALOGIA
Abstract

In the last decades many studies have been focusing on Carbon Capture and Storage(CCS) to find a possible remedy to reduce the large increase of anthropogenic carbon dioxide. Mineral Carbonation (MC) is a potential solution for almost irreversible chemical long-term CCS. It concerns the combination of CaO and MgO with carbon dioxide forming spontaneously and exothermically dolomite and magnesite. However, kinetic barriers pose sever limitations for the practical exploitation of this reaction. High fractions of MgO are available in silicates such as olivine, orthopyroxene, clinopyroxene and serpentine. To date, data reported that serpentine polymorphs, above all antigorite, is an excellent candidate for fixing the carbon dioxide as the reaction efficiency is approximately 92% compared to lizardite (40%) and olivine (66%). This is due to the surface reactivity of approximately 18.7 m^2/g for the dehydrated antigorite comparedto10.8 m^2/g for dehydrated lizardite and 4.6 m^2/g for olivine. The microwave assisted process for CCS is an innovative technology that can be employed to catalyze the reaction through thermal and non-thermal mechanisms. Some pioneering tests of direct carbonation by microwave hydrothermal equipment have been performed on olivine, lizardite and chrysotile powders [1] but not on antigorite. The structure of serpentine is characterized by corrugated stacked layers of silica and brucite. For this reason, MC involves dissolution of silica layers, dissolution/dehydration of brucite layers, and precipitation of magnesium carbonate. To address the chemical response of the single phases, experiments have been performed by both a local microwave-source acting locally on a specific crystal surface and a volume source interacting with an ensemble of grains on synthetic powders and single crystals of pure brucite and talc. In a second step, treatments have been extended to chrysotile, lizardite and antigorite. A characterization of the mechanism and kinetics were performed by scanning probe microscopy on the surface of single crystals phases, supported by Raman spectroscopy and by Scanning and Transmission Electron Microscopy study performed on micro- and nano-sized grains. [1] White, et al. Reaction mechanisms of magnesium silicates with carbon dioxide in microwave fields. Final Report to the U.S. Department of Energy, National Energy Technology Laboratory (2004)

Published
2022

6. The intracrystalline microstructure of Monte Fico lizardite, by optics, μ-Raman spectroscopy and TEM

Author

Capitani G., Compagnoni R., Cossio R., Botta S., Mellini M., Capitani, G, Compagnoni, R, Cossio, R, Botta, S, and Mellini, M

Subjects
Sepentino, Lizardite, Monte Fico, Raman, TEM
Abstract

The Monte Fico lizardite crystals have an internal skeletal spongy microstructure, formed by two micrometric domains having different optical reliefs. This intracrystalline microstructure parallels the previously reported intercrystalline arrangement, consisting of lizardite prisms within a chrysotile plus polygonal serpentine matrix. In the high-wavenumber region, the larger and more abundant domains (that represent approximately 87ĝ€¯% of the total field view) produce μ-Raman spectra characterized by two major peaks at 3686 and 3705ĝ€¯cm-1. The smaller, less abundant domains present a wide band confined between these wavenumbers. These features are interpreted as lizardite and chrysotile, respectively. Raman results are confirmed by TEM, which emphasizes the presence of well-recognizable polygonal serpentine too. Tight crystallographic control exists between lizardite and this first serpentine generation. A second serpentine generation occurs perpendicularly to the first one. The lizardite crystals grew up with a skeletal habit, whereas chrysotile fibres and polygonal serpentine filled the voids, growing epitactically on the lizardite crystals, with fast crystal growth in a fluid-rich environment.

Published
2021

7. Life-threatening strongyloidosis in a puppy

Author

Colombo, M, Capitani, G, Morelli, S, and Di Cesare, A

Subjects
Italy, Puppy, Baermann, Strongyloides stercoralis, Puppy, Italy, Baermann, Strongyloides stercoralis
Published
2021

8. Fe-rich antigorite: a rock-forming mineral from low-temperature/high-pressure meta-ophicarbonates

Author

Di Pierro S.[1, 2, Groppo C.[1, Compagnoni R.[1], Capitani G.[4], Mellini M.[5], Di Pierro, S, Groppo, C, Compagnoni, R, Capitani, G, and Mellini, M

Subjects
Mineral, blueschist-facies metamorphism, Meta-ophicarbonate, Fe-rich antigorite, meta-ophicarbonates, Transmission Electron Microscopy, thermodynamic modelling, H2O-CO2 fluid, serpentine, Mineralogy, Trasmission Electron Microscopy, CO, Geochemistry and Petrology, Transmission electron microscopy, High pressure, blueschistfacies metamorphism, Geology, fluid
Abstract

This study provides the first characterization of Fe-rich antigorite (FeOtot up to 12 wt%), a rock-forming mineral occurring in ophicarbonate rocks from different low-temperature/high-pressure meta-ophiolitic suites: Acceglio (Traversiera Valley, external Piemonte Zone, NW Italy), Macedonia and Verias (Thessaloniki and Vurinos-Kozani ophiolitic complexes, NE Greece), Tinos (Tinos Island, Cyclades Archipelago, Greece). Fe-rich antigorite has been characterized through optical and transmission electron microscopy (TEM), and its mineral chemistry has been investigated by means of wavelength-dispersive and TEM-based energy dispersive spectrometry. In thin section, Fe-rich antigorite is characterized by a strong, peculiar pleochroism (alfa = green-dark green; gamma = bright-yellow-orange). It occurs in both mesh and bastite microstructures, and it is locally associated with relics of lizardite and/ or chrysotile. The modulated lattice parameters of disordered Fe-rich antigorites have been determined by electron diffraction in the transmission electron microscope. The values are highly variable, even within each ophicarbonate sample. Verias dominantly has a superlattice parameter a clustering around 43.5 Å (corresponding to the m = 17 polysome); Tinos and Macedonia have around 35.4 Å (m = 14); Acceglio may even go down to 29 Å (m = 12). Globally, the disorder features (i.e., reduced size of crystals, polysomatic faults, wobbling, misalignment among sublattice and superlattice reflections, etc.) increase from Macedonia to Verias, Tinos and Acceglio, respectively. The analyzed Fe-rich antigorites accommodate up to 12 wt% FeOtot, with XFe values (XFe = Fetot/[Mg + Fetot]) in the range 0.10-0.16 for Macedonia, 0.05-0.17 for Acceglio, 0.10-0.12 for Tinos and 0.05-0.10 for Verias. The intensity of the pleochroism seems to be directly correlated with the Fe content, with the Fe-richer samples showing the deeper absorption colours. Mineral relationships and TEM observations suggest that Fe-rich antigorite replaces former mesh and bastite microstructures consisting of lizardite ± chrysotile, only locally preserved as relict phases. The thermodynamic modelling approach (i.e., P/T-X(CO2) pseudosection) qualitatively shows that the stability of Fe-rich antigorite is compatible with low-temperature, high-pressure conditions (i.e., blueschist-facies metamorphic conditions), and is enhanced by the occurrence of CO2 in the fluid, consistent with the systematic occurrence of this mineral in meta-ophicarbonate rocks.

Published
2019
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9. Azimuthal single- and double-spin asymmetries in semi-inclusive deep-inelastic lepton scattering by transversely polarized protons

Author

Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Avakian, R., Bacchetta, A., Belostotski, S., Bryzgalov, V., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Elbakian, G., Ellinghaus, F., Fantoni, A., Felawka, L., Gavrilov, G., Gharibyan, V., Holler, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Kinney, E., Kisselev, A., Kozlov, V., Kravchenko, P., Lagamba, L., Lapikás, L., Lenisa, P., Lorenzon, W., Manaenkov, S. I., Marianski, B., Marukyan, H., Miyachi, Y., Movsisyan, A., Muccifora, V., Naryshkin, Y., Nass, A., Nazaryan, G., Nowak, W.-D., Pappalardo, L. L., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Schäfer, A., Schnell, G., Seitz, B., Shibata, T.-A., Shutov, V., Statera, M., Terkulov, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vilardi, I., Yaschenko, S., Zeiler, D., Zihlmann, B., and Zupranski, P.

Subjects
electron p: deep inelastic scattering, pi: leptoproduction, deep inelastic scattering: semi-inclusive reaction, dimension: 3, p: polarized beam, Nuclear Theory, lepton: beam, HERMES, lepton: scattering, anti-p, Sivers function, modulation, phase space, DESY HERA Stor, kinematics, polarization: transverse, High Energy Physics::Experiment, Collins, Nuclear Experiment, spin: asymmetry, experimental results
Abstract

A comprehensive set of azimuthal single-spin and double-spin asymmetries in semi-inclusive leptoproduction of pions, charged kaons, protons, and antiprotons from transversely polarized protons is presented. These asymmetries include the previously published HERMES results on Collins and Sivers asymmetries, the analysis of which has been extended to include protons and antiprotons and also to an extraction in a three-dimensional kinematic binning and enlarged phase space. They are complemented by corresponding results for the remaining four single-spin and four double-spin asymmetries allowed in the one-photon-exchange approximation of the semi-inclusive deep-inelastic scattering process for target-polarization orientation perpendicular to the direction of the incoming lepton beam. Among those results, significant non-vanishing $\cos{\phi-\phi_S}$ modulations provide evidence for a sizable worm-gear (II) distribution, $g_{1T}$. Most of the other modulations are found to be consistent with zero with the notable exception of large $\sin{\phi_S}$ modulations for charged pions and positive kaons.

Published
2020
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10. Longitudinal double-spin asymmetries in semi-inclusive deep-inelastic scattering of electrons and positrons by protons and deuterons

Author

Airapetian, A., Akopov, N., Bryzgalov, V., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Nardo, L., De Sanctis, E., Akopov, Z., Diefenthaler, M., Di Nezza, P., Düren, M., Elbakian, G., Ellinghaus, F., Fantoni, A., Felawka, L., Frullani, S., Gavrilov, G., Gharibyan, V., Aschenauer, E. C., Giordano, F., Gliske, S., Hasch, D., Holler, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Augustyniak, W., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Lehmann, I., Lorenzon, W., Avakian, R., Ma, B.-Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Miyachi, Y., Movsisyan, A., Muccifora, V., Mussgiller, A., Avetissian, A., Naryshkin, Y., Nass, A., Nazaryan, G., Nowak, W.-D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, Anush, Reimer, P. E., Reolon, A. R., Riedl, C., Belostotski, S., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Schnell, G., Seitz, B., Shibata, T.-A., Statera, M., Blok, H. P., Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., van der Nat, P. B., Van Haarlem, Y., Van Hulse, C., Borissov, A., Veretennikov, D., Vikhrov, V., Vilardi, I., Vogel, Christian, Wang, S., Yaschenko, S., Zihlmann, B., Zupranski, P., HERMES Collaboration, and Student Lab and Education

Subjects
Proton, charged-lepton interactions with hadrons, media_common.quotation_subject, Particle interactions, HELICITY, Hadron, Nuclear Theory, Socio-culturale, FOS: Physical sciences, Strong interaction, Polarization in interactions &amp, 01 natural sciences, 7. Clean energy, Asymmetry, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), Pion, Strong interaction, Particle interactions, Deep inelastic scattering, Photon & charged-lepton interactions with hadrons, Polarization in interactions & scattering, Quantum chromodynamics, 0103 physical sciences, DISTRIBUTIONS, ddc:530, SDG 7 - Affordable and Clean Energy, valence, 010306 general physics, Nuclear Experiment, media_common, Physics, 010308 nuclear & particles physics, Scattering, polarized quark distributions, scattering, nucleon, electroproduction, Deep inelastic scattering, Helicity, Photon &amp, High Energy Physics - Phenomenology, Physics and Astronomy, helicity distributions, High Energy Physics::Experiment, Nucleon, Quantum chromodynamics, azimuthal dependence
Abstract

A comprehensive collection of results on longitudinal double-spin asymmetries is presented for charged pions and kaons produced in semi-inclusive deep-inelastic scattering of electrons and positrons on the proton and deuteron, based on the full HERMES data set. The dependence of the asymmetries on hadron transverse momentum and azimuthal angle extends the sensitivity to the flavor structure of the nucleon beyond the distribution functions accessible in the collinear framework. No strong dependence on those variables is observed. In addition, the hadron charge-difference asymmetry is presented, which under certain model assumptions provides access to the helicity distributions of valence quarks. We gratefully acknowledge the DESY management for its support, the staff at DESY and the collaborating institutions for their significant effort. This work was supported by the State Committee of Science of the Republic of Armenia, Grant No. 18T-1C180; the FWO-Flanders and IWT, Belgium; the Natural Sciences and Engineering Research Council of Canada; the National Natural Science Foundation of China; the Alexander von Humboldt Stiftung, the German Bundesministerium fur Bildung und Forschung (BMBF), and the Deutsche Forschungsgemeinschaft (DFG); the Italian Istituto Nazionale di Fisica Nucleare (INFN); the MEXT, JSPS, and G-COE of Japan; the Dutch Foundation for Fundamenteel Onderzoek der Materie (FOM); the Russian Academy of Science and the Russian Federal Agency for Science and Innovations; the Basque Foundation for Science (IKERBASQUE), the Basque Government, Grant No. IT956-16, and MINECO (Juan de la Cierva), Spain; the U.K. Engineering and Physical Sciences Research Council, the Science and Technology Facilities Council, and the Scottish Universities Physics Alliance; as well as the U.S. Department of Energy (DOE) and the National Science Foundation (NSF).

Published
2019
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11. Longitudinal double-spin asymmetries in semi-inclusive deep-inelastic scattering of electrons and positrons by protons and deuterons

Author

Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Belostotski, S., Blok, H. P., Borissov, A., Bryzgalov, V., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Nardo, L., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Elbakian, G., Ellinghaus, F., Fantoni, A., Felawka, L., Frullani, S., Gavrilov, G., Gharibyan, V., Giordano, F., Gliske, S., Hasch, D., Holler, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Lehmann, I., Lorenzon, W., Ma, B.-Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Miyachi, Y., Movsisyan, A., Muccifora, V., Mussgiller, A., Naryshkin, Y., Nass, A., Nazaryan, G., Nowak, W.-D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, Anush, Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Schnell, G., Seitz, B., Shibata, T.-A., Statera, M., Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Der Nat, P. B., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Vogel, Christian, Wang, S., Yaschenko, S., Zihlmann, B., and Zupranski, P.

Abstract

Physical review / D 99(11), 112001 (2019). doi:10.1103/PhysRevD.99.112001, A comprehensive collection of results on longitudinal double-spin asymmetries is presented for charged pions and kaons produced in semi-inclusive deep-inelastic scattering of electrons and positrons on the proton and deuteron, based on the full HERMES data set. The dependence of the asymmetries on hadron transverse momentum and azimuthal angle extends the sensitivity to the flavor structure of the nucleon beyond the distribution functions accessible in the collinear framework. No strong dependence on those variables is observed. In addition, the hadron charge-difference asymmetry is presented, which under certain model assumptions provides access to the helicity distributions of valence quarks., Published by APS, College Park, MD

Published
2019
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12. Beam-helicity asymmetries for single-hadron production in semi-inclusive deep-inelastic scattering from unpolarized hydrogen and deuterium targets

Author

Airapetian, Avetik, Akopov, Norair, Akopov, Zaven, Aschenauer, Elke-Caroline, Augustyniak, Witold, Belostotski, Stanislav, Blok, Henk, Bryzgalov, V., Capitani, G., Cisbani, E., Ciulli, G., Contalbrigo, Marco, Deconinck, Wouter, Sanctis, Enzo De, Diefenthaler, Markus, DiNezza, Pasquale, Dueren, Michael, Elbakyan, Garegin, Ellinghaus, Frank, Felawka, Larry, Gapienko, G., Garibaldi, F., Gavrilov, Gennady, Gharibyan, Vahagn, Hillenbrand, Achim, Holler, Yorck, Ivanilov, A., Jackson, Harold, Joosten, Sylvester, Kaiser, Ralf, Kinney, Edward, Kisselev, A., Korotkov, Vladislav, Kozlov, V., Kravchenko, Polina, Lagamba, L., Lapikas, L., Lehmann, Inti, Lenisa, Paolo, Lorenzon, W., Manaenkov, S., Marianski, Bohdan, Marukyan, Hrachya, Movsisyan, Aram, Muccifora, V., Nass, A., Nazaryan, Gevorg, Nowak, Wolf-Dieter, Pappalardo, Luciano, Reolon, A., Riedl, Caroline, Rith, Klaus, Rosner, G., Rostomyan, Armine, Ryckbosch, D., Schnell, Gunar, Seitz, B., Shutov, Vitaly, Statera, M., Terkulov, A., Trzcinski, A., Tytgat, M., Haarlem, Yves Van, Hulse, Charlotte Van, Veretennikov, Denis, Vilardi, I., Vogel, Christian, Yashchenko, Sergey, Zagrebelnyy, Vitaly, Zeiler, D., Zihlmann, B., and Warsaw I, P. Zupranski

Subjects
Nuclear Theory, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment
Abstract

A measurement of beam-helicity asymmetries for single-hadron production in deep-inelastic scattering is presented. Data from the scattering of 27.6 GeV electrons and positrons off gaseous hydrogen and deuterium targets were collected by the HERMES experiment. The asymmetries are presented separately as a function of the Bjorken scaling variable, the hadron transverse momentum and the fractional energy for charged pions and kaons as well as for protons and anti-protons. These asymmetries are also presented as a function of the three aforementioned kinematic variables simultaneously.

Published
2019
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14. Longitudinal double-spin asymmetries in semi-inclusive deep-inelastic scattering of electrons and positrons by protons and deuterons

Author

Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Belostotski, S., Blok, H. P., Borissov, A., Bryzgalov, V., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Nardo, L., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Elbakian, G., Ellinghaus, F., Fantoni, A., Felawka, L., Frullani, S., Gavrilov, G., Gharibyan, V., Giordano, F., Gliske, S., Hasch, D., Holler, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Lehmann, I., Lorenzon, W., Ma, B. -Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Miyachi, Y., Movsisyan, A., Muccifora, V., Mussgiller, A., Naryshkin, Y., Nass, A., Nazaryan, G., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Schnell, G., Seitz, B., Shibata, T. -A., Statera, M., Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Der Nat, P. B., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Vogel, C., Wang, S., Yaschenko, S., Zihlmann, B., and Zupranski, P.

Subjects
Nuclear Theory, High Energy Physics::Experiment, Nuclear Experiment
Abstract

A comprehensive collection of results on longitudinal double-spin asymmetries is presented for charged pions and kaons produced in semi-inclusive deep-inelastic scattering of electrons and positrons on the proton and deuteron, based on the full HERMES data set. The dependence of the asymmetries on hadron transverse momentum and azimuthal angle extends the sensitivity to the flavor structure of the nucleon beyond the distribution functions accessible in the collinear framework. No strong dependence on those variables is observed. In addition, the hadron charge-difference asymmetry is presented, which under certain model assumptions provides access to the helicity distributions of valence quarks.

Published
2018
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15. Ratios of helicity amplitudes for exclusive ρ0 electroproduction on transversely polarized protons

Author

Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Belostotski, S., Blok, H. P., Borissov, A., Bryzgalov, V., Capitani, G. P., Ciullo, G., Contalbrigo, M., Deconinck, W., De Leo, R., De Sanctis, E., Düren, M., Elbakian, G., Ellinghaus, F., Felawka, L., Frullani, S., Garibaldi, F., Gavrilov, G., Gharibyan, V., Goloskokov, S. V., Holler, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Kroll, P., Lagamba, L., Lapikás, L., Lehmann, I., Lenisa, P., Lorenzon, W., Manaenkov, S. I., Marianski, B., Marukyan, H., Miyachi, Y., Movsisyan, A., Muccifora, V., Nass, A., Nowak, W. D., Pappalardo, L. L., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Ryckbosch, D., Salomatin, Y., Schäfer, A., Schnell, G., Seitz, B., Shibata, T. A., Shutov, V., Statera, M., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Yaschenko, S., Zihlmann, B., Zupranski, P., and Student Lab and Education

Subjects
Bersagli Nucleari Polarizzati, Socio-culturale, Positroni Polarizzati, High Energy Physics::Experiment, Produzione di mesoni in collissioni profondamente anelastiche, Polarizzazione, Nuclear Experiment
Abstract

Exclusive ρ0-meson electroproduction is studied by the HERMES experiment, using the 27.6 GeV longitudinally polarized electron/positron beam of HERA and a transversely polarized hydrogen target, in the kinematic region 1.0 GeV2< Q2< 7.0 GeV2, 3.0 GeV < W< 6.3 GeV, and - t′< 0.4 GeV2. Using an unbinned maximum-likelihood method, 25 parameters are extracted. These determine the real and imaginary parts of the ratios of several helicity amplitudes describing ρ0-meson production by a virtual photon. The denominator of those ratios is the dominant amplitude, the nucleon-helicity-non-flip amplitude F012012, which describes the production of a longitudinal ρ0-meson by a longitudinal virtual photon. The ratios of nucleon-helicity-non-flip amplitudes are found to be in good agreement with those from the previous HERMES analysis. The transverse target polarization allows for the first time the extraction of ratios of a number of nucleon-helicity-flip amplitudes to F012012. Results obtained in a handbag approach based on generalized parton distributions taking into account the contribution from pion exchange are found to be in good agreement with these ratios. Within the model, the data favor a positive sign for the π- ρ transition form factor. By also exploiting the longitudinal beam polarization, a total of 71 ρ0 spin-density matrix elements is determined from the extracted 25 parameters, in contrast to only 53 elements as directly determined in earlier analyses.

Published
2017
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16. Ratios of helicity amplitudes for exclusive $\rho ^0$ electroproduction on transversely polarized protons

Author

Airapetian, A., Akopov, N., Ciullo, G., Contalbrigo, M., Deconinck, W., De Leo, R., De Sanctis, E., Düren, M., Elbakian, G., Ellinghaus, F., Felawka, L., Frullani, S., Akopov, Z., Garibaldi, F., Gavrilov, G., Gharibyan, V., Goloskokov, S. V., Holler, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Aschenauer, E. C., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Kroll, P., Lagamba, L., Lapikás, L., Lehmann, I., Lenisa, P., Lorenzon, W., Augustyniak, W., Manaenkov, S. I., Marianski, B., Marukyan, H., Miyachi, Y., Movsisyan, A., Muccifora, V., Nass, A., Nowak, W. -D., Pappalardo, L. L., Petrosyan, Anush, Belostotski, S., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Ryckbosch, D., Salomatin, Y., Schäfer, A., Schnell, G., Blok, H. P., Seitz, B., Shibata, T. -A., Shutov, V., Statera, M., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Borissov, A., Veretennikov, D., Vikhrov, V., Vilardi, I., Yaschenko, S., Zihlmann, B., Zupranski, P., HERMES Collaboration, Bryzgalov, V., and Capitani, G. P.

Subjects
High Energy Physics - Phenomenology, High Energy Physics::Experiment, ddc:530, Nuclear Experiment, High Energy Physics - Experiment
Abstract

Exclusive $\rho^0$-meson electroproduction is studied by the HERMES experiment, using the 27.6 GeV longitudinally polarized electron/positron beam of HERA and a transversely polarized hydrogen target, in the kinematic region 1.0 GeV$^2$ < Q$^2$ < 7.0 GeV$^2$, 3.0 GeV < W < 6.3 GeV, and -t’ < 0.4 GeV$^2$. Using an unbinned maximum-likelihood method, 25 parameters are extracted. These determine the real and imaginary parts of the ratios of several helicity amplitudes describing $\rho^0$-meson production by a virtual photon. The denominator of those ratios is the dominant amplitude, the nucleon-helicity-non-flip amplitude $F_{0\frac{1}{2}0\frac{1}{2}}$, which describes the production of a longitudinal $\rho^0$-meson by a longitudinal virtual photon. The ratios of nucleon-helicity-non-flip amplitudes are found to be in good agreement with those from the previous HERMES analysis. The transverse target polarization allows for the first time the extraction of ratios of a number of nucleon-helicity-flip amplitudes to $F_{0\frac{1}{2}0\frac{1}{2}}$. Results obtained in a handbag approach based on generalized parton distributions taking into account the contribution from pion exchange are found to be in good agreement with these ratios. Within the model, the data favor a positive sign for the $\pi-\rho$ transition form factor. By also exploiting the longitudinal beam polarization, a total of 71 $\rho^0$ spin-density matrix elements is determined from the extracted 25 parameters, in contrast to only 53 elements as directly determined in earlier analyses.

Published
2017
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17. Ratios of helicity amplitudes for exclusive $\rho^0$ electroproduction on transversely polarized protons

Author

Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Belostotski, S., Blok, H. P., Borissov, A., Bryzgalov, V., Capitani, G. P., Ciullo, G., Contalbrigo, M., Deconinck, W., De Leo, R., De Sanctis, E., Düren, M., Elbakian, G., Ellinghaus, F., Felawka, L., Frullani, S., Garibaldi, F., Gavrilov, G., Gharibyan, V., Goloskokov, S. V., Holler, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Kroll, P., Lagamba, L., Lapikás, L., Lehmann, I., Lenisa, P., Lorenzon, W., Manaenkov, S. I., Marianski, B., Marukyan, H., Miyachi, Y., Movsisyan, A., Muccifora, V., Nass, A., Nowak, W. -D., Pappalardo, L. L., Petrosyan, Anush, Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Ryckbosch, D., Salomatin, Y., Schäfer, A., Schnell, G., Seitz, B., Shibata, T. -A., Shutov, V., Statera, M., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Yaschenko, S., Zihlmann, B., Zupranski, P., and HERMES Collaboration

Subjects
Astrophysics::High Energy Astrophysical Phenomena, High Energy Physics::Phenomenology, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment
Abstract

Exclusive $\rho^0$-meson electroproduction is studied by the HERMES experiment, using the 27.6 GeV longitudinally polarized electron/positron beam of HERA and a transversely polarized hydrogen target, in the kinematic region 1.0 GeV$^2$

Published
2017
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18. Ratios of helicity amplitudes for exclusive $\rho ^0$ electroproduction on transversely polarized protons

Author

Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Belostotski, S., Blok, H. P., Borissov, A., Bryzgalov, V., Capitani, G. P., Ciullo, G., Contalbrigo, M., Deconinck, W., De Leo, R., De Sanctis, E., Düren, M., Elbakian, G., Ellinghaus, F., Felawka, L., Frullani, S., Garibaldi, F., Gavrilov, G., Gharibyan, V., Goloskokov, S. V., Holler, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Kroll, P., Lagamba, L., Lapikás, L., Lehmann, I., Lenisa, P., Lorenzon, W., Manaenkov, S. I., Marianski, B., Marukyan, H., Miyachi, Y., Movsisyan, A., Muccifora, V., Nass, A., Nowak, W.-D., Pappalardo, L. L., Petrosyan, Anush, Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Ryckbosch, D., Salomatin, Y., Schaefer, Andreas, Schnell, G., Seitz, B., Shibata, T.-A., Shutov, V., Statera, M., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Yaschenko, S., Zihlmann, B., and Zupranski, P.

Abstract

The European physical journal / C 77(6), 378(2017). doi:10.1140/epjc/s10052-017-4899-1, Exclusive $\rho^0$-meson electroproduction is studied by the HERMES experiment, using the 27.6 GeV longitudinally polarized electron/positron beam of HERA and a transversely polarized hydrogen target, in the kinematic region 1.0 GeV$^2$ < Q$^2$ < 7.0 GeV$^2$, 3.0 GeV < W < 6.3 GeV, and -t’ < 0.4 GeV$^2$. Using an unbinned maximum-likelihood method, 25 parameters are extracted. These determine the real and imaginary parts of the ratios of several helicity amplitudes describing $\rho^0$-meson production by a virtual photon. The denominator of those ratios is the dominant amplitude, the nucleon-helicity-non-flip amplitude $F_{0\frac{1}{2}0\frac{1}{2}}$, which describes the production of a longitudinal $\rho^0$-meson by a longitudinal virtual photon. The ratios of nucleon-helicity-non-flip amplitudes are found to be in good agreement with those from the previous HERMES analysis. The transverse target polarization allows for the first time the extraction of ratios of a number of nucleon-helicity-flip amplitudes to $F_{0\frac{1}{2}0\frac{1}{2}}$. Results obtained in a handbag approach based on generalized parton distributions taking into account the contribution from pion exchange are found to be in good agreement with these ratios. Within the model, the data favor a positive sign for the $\pi-\rho$ transition form factor. By also exploiting the longitudinal beam polarization, a total of 71 $\rho^0$ spin-density matrix elements is determined from the extracted 25 parameters, in contrast to only 53 elements as directly determined in earlier analyses., Published by Springer, Berlin

Published
2017
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20. Erratum to: Spin density matrix elements in exclusive ω electroproduction on 1H and 2H targets at 27.5 GeV beam energy

Author

Airapetian, A., Akopov, N., Akopov, Z., Augustyniak, W., Avetissian, A., Blok, H. P., Borissov, A., Bryzgalov, V., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Etzelmüller, E., Fabbri, R., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Lehmann, I., Lenisa, P., Lorenzon, W., Ma, B.-Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Movsisyan, A., Murray, M., Naryshkin, Y., Nass, A., Nowak, W.-D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rostomyan, A., Ryckbosch, D., Schäfer, A., Schnell, G., Schüler, K. P., Seitz, B., Shibata, T.-A., Stahl, M., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Yen, S., Zeiler, D., Zihlmann, B., and Zupranski, P.

Abstract

No abstract available.

Published
2016

21. Spin density matrix elements in exclusive omega electroproduction on H-1 and H-2 targets at 27.5 GeV beam energy (vol 74, 3110, 2014)

Author

Airapetian, A., Akopov, N., Akopov, Z., Augustyniak, W., Avetissian, A., Blok, H. P., Borissov, A., Bryzgalov, V., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, Giuseppe, Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Dueren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Etzelmueller, E., Fabbri, R., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikas, L., Lehmann, I., Lenisa, Paolo, Lorenzon, W., B. Q., Ma, Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Movsisyan, A., Murray, M., Naryshkin, Y., Nass, A., Nowak, W. D., Pappalardo, Luciano Libero, Perez Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rostomyan, A., Ryckbosch, D., Schaefer, A., Schnell, G., Schueler, K. P., Seitz, B., Shibata, T. A., Stahl, M., Stancari, M., Statera, Marco, Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Yen, S., Zeiler, D., Zihlmann, B., and Zupranski, P.

Subjects
PHYSICS, MINIMAL FLAVOR VIOLATION, SYMMETRY, SEARCH, STANDARD MODEL, HIGGS-BOSON, DECAYS, LHC, COUPLINGS, PARTICLE, Socio-culturale
Published
2016

22. Erratum to: Spin density matrix elements in exclusive $\mathrm{\omega}$ electroproduction on $\mathrm{^1H}$ and $\mathrm{^2H}$ targets at 27.5 GeV beam energy

Author

Airapetian, A., Akopov, N., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Akopov, Z., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Etzelmüller, E., Fabbri, R., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Augustyniak, W., Garibaldi, F., Gavrilov, G., Gharibyan, V., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Ivanilov, A., Jackson, H. E., Joosten, S., Avetissian, A., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Blok, H. P., Lapikás, L., Lehmann, I., Lenisa, P., Lorenzon, W., Ma, B.-Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Borissov, A., Movsisyan, A., Murray, M., Naryshkin, Y., Nass, A., Nowak, W.-D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, Anush, Reimer, P. E., Reolon, A. R., Bryzgalov, V., Riedl, C., Rith, K., Rostomyan, A., Ryckbosch, D., Schäfer, A., Schnell, G., Schüler, K. P., Seitz, B., Shibata, T.-A., Stahl, M., Capiluppi, M., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Capitani, G. P., Van Hulse, C., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Yen, S., Zeiler, D., Zihlmann, B., Zupranski, P., and HERMES Collaboration

Subjects
ddc:530
Abstract

It has been found that three of the spin-density matrix elements (SDMEs) in Fig. 6 of the published paper were incorrectly labeled. The labels have been fixed, while none of the results or conclusions have changed.

Published
2016
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23. Erratum to: Spin density matrix elements in exclusive $\omega$ electroproduction on $^1$H and $^2$H targets at 27.5 GeV beam energy

Author

Airapetian, A., Akopov, N., Akopov, Z., Augustyniak, W., Avetissian, A., Blok, H. P., Borissov, A., Bryzgalov, V., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Etzelmüller, E., Fabbri, R., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Lehmann, I., Lenisa, P., Lorenzon, W., Ma, B.-Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Movsisyan, A., Murray, M., Naryshkin, Y., Nass, A., Nowak, W.-D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, Anush, Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rostomyan, A., Ryckbosch, D., Schäfer, A., Schnell, G., Schüler, K. P., Seitz, B., Shibata, T.-A., Stahl, M., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Yen, S., Zeiler, D., Zihlmann, B., and Zupranski, P.

Abstract

The European physical journal / C 76(3), 162(2016). doi:10.1140/epjc/s10052-016-3996-x, It has been found that three of the spin-density matrix elements (SDMEs) in Fig. 6 of the published paper were incorrectly labeled. The labels have been fixed, while none of the results or conclusions have changed., Published by Springer, Berlin

Published
2016
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24. Spin density matrix elements in exclusive rho (0) electroproduction on H-1 and H-2 targets at 27.5 GeV beam energy

Author

Airapetian, A., Akopov, N., Akopov, Z., Andrus, A., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetissian, E., Belostotski, S., Bianchi, N., Blok, H. P., Böttcher, H., Bonomo, C., Borissov, A., Brüll, A., Bryzgalov, V., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., Demey, M., De Nardo, L., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Dreschler, J., Düren, M., Ehrenfried, M., Elalaoui-Moulay, A., Elbakian, G., Ellinghaus, F., Elschenbroich, U., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Funel, A., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, F., Gliske, S., Grebeniouk, O., Gregor, I. M., Guler, H., Hadjidakis, C., Hartig, M., Hasch, D., Hasegawa, T., Hesselink, W. H. A., Hill, G., Hillenbrand, A., Hoek, M., Holler, Y., Hommez, B., Hristova, I., Iarygin, G., Imazu, Y., Ivanilov, A., Izotov, A., Jackson, H. E., Jgoun, A., Kaiser, R., Keri, T., Kinney, E., Kisselev, A., Kobayashi, T., Kopytin, M., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lamb, R., Lapikás, L., Lehmann, I., Lenisa, P., Liebing, P., Linden-Levy, L. A., Lorenzon, W., Lu, S., Lu, X.-R., Ma, B.-Q., Maiheu, B., Makins, N. C. R., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Mexner, V., Miller, C. A., Miyachi, Y., Muccifora, V., Murray, M., Mussgiller, A., Nagaitsev, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W.-D., Osborne, A., Pappalardo, L. L., Perez-Benito, R., Pickert, N., Raithel, M., Reggiani, D., Reimer, P. E., Reischl, A., Reolon, A. R., Riedl, C., Rith, K., Rock, S. E., Rosner, G., Rostomyan, A., Rubacek, L., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanjiev, I., Schäfer, A., Schnell, G., Schüler, K. P., Seitz, B., Shearer, C., Shibata, T.-A., Shutov, V., Stancari, M., Statera, M., Steffens, J. E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stinzing, F., Streit, J., Tait, P., Taroian, S., Tchuiko, B., Terkulov, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., van der Nat, P. B., van der Steenhoven, G., Van Haarlem, Y., Van Hulse, C., Varanda, M., Veretennikov, D., Vikhrov, V., Vilardi, I., Vogel, C., Wang, S., Yaschenko, S., Ye, H., Ye, Y., Ye, Z., Yen, S., Yu, W., Zeiler, D., Zihlmann, B., Zupranski, P., (Astro)-Particles Physics, Photo Conversion Materials, Network Institute, Student Lab and Education, and Artificial Intelligence (section level)

Subjects
HERMES experiment, Particle physics, Hydrogen, Physics and Astronomy (miscellaneous), FOS: Physical sciences, chemistry.chemical_element, Kinematics, 01 natural sciences, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), 0103 physical sciences, SDG 14 - Life Below Water, Nuclear Experiment, 010306 general physics, Engineering (miscellaneous), Physics, 010308 nuclear & particles physics, Polarization (waves), Helicity, Amplitude, Deuterium, chemistry, High Energy Physics::Experiment, Condensed Matter::Strongly Correlated Electrons, Beam energy
Abstract

Spin Density Matrix Elements (SDMEs) describing the angular distribution of exclusive rho^0 electroproduction and decay are determined in the HERMES experiment with 27.6 GeV beam energy and unpolarized hydrogen and deuterium targets. Eight (fifteen) SDMEs that are related (unrelated) to the longitudinal polarization of the beam are extracted in the kinematic region 1 GeV^2 < Q^2 < 7 GeV^2, 3.0 GeV < W < 6.3 GeV, and -t < 0.4 GeV^2. Within the given experimental uncertainties, a hierarchy of relative sizes of helicity amplitudes is observed. Kinematic dependences of all SDMEs on Q^2 and t are presented, as well as the longitudinal-to-transverse rho^0 electroproduction cross section ratio as a function of Q^2. A small but statistically significant deviation from the hypothesis of s-channel helicity conservation is observed. An indication is seen of a contribution of unnatural-parity-exchange amplitudes; these amplitudes are naturally generated with a quark-exchange mechanism., 41 pages, 20 figures, 16 table; revised version corrects small typos, text clarified on 6 pages, two references added and new data added to figure 20

Published
2009
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25. Transverse-target-spin asymmetry in exclusive ω -meson electroproduction

Author

Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Avetissian, A., Belostotski, S., Blok, H. P., Borissov, A., Bryzgalov, V., Capitani, G. P., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Elbakian, G., Ellinghaus, F., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Gharibyan, V., Giordano, F., Gliske, S., Hasch, D., Hoek, M., Holler, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Lehmann, I., Lenisa, P., Lorenzon, W., Ma, B.-Q., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Miyachi, Y., Movsisyan, A., Muccifora, V., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W.-D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Schnell, G., Seitz, B., Shibata, T.-A., Statera, M., Steffens, E., Steijger, J. J. M., Stinzing, F., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Vikhrov, V., Vilardi, I., Vogel, C., Wang, S., Yaschenko, S., Yen, S., Zihlmann, B., and Zupranski, P.

Subjects
ENERGY, Physics and Astronomy, LEPTOPRODUCTION, PARTON DISTRIBUTIONS, High Energy Physics::Experiment, LEPTON SCATTERING, Nuclear Experiment, QCD
Abstract

Hard exclusive electroproduction of omega mesons is studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target. The amplitudes of five azimuthal modulations of the single-spin asymmetry of the cross section with respect to the transverse proton polarization are measured. They are determined in the entire kinematic region as well as for two bins in photon virtuality and momentum transfer to the nucleon. Also, a separation of asymmetry amplitudes into longitudinal and transverse components is done. These results are compared to a phenomenological model that includes the pion pole contribution. Within this model, the data favor a positive pi omega transition form factor.

Published
2015

26. Spin density matrix elements in exclusive ω electroproduction on 1H and 2H targets at 27.5 GeV beam energy

Author

Airapetian, A., Akopov, N., Akopov, Z., Augustyniak, W., Avetissian, A., Blok, H. P., Borissov, A., Bryzgalov, V., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Etzelmüller, E., Fabbri, R., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Lehmann, I., Lenisa, P., Lorenzon, W., Ma, B.-Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Movsisyan, A., Murray, M., Naryshkin, Y., Nass, A., Nowak, W.-D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rostomyan, A., Ryckbosch, D., Schäfer, A., Schnell, G., Schüler, K. P., Seitz, B., Shibata, T.-A., Stahl, M., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Yen, S., Zeiler, D., Zihlmann, B., and Zupranski, P.

Subjects
High Energy Physics::Experiment, Nuclear Experiment
Abstract

Exclusive electroproduction of ω mesons on unpolarized hydrogen and deuterium targets is studied in the kinematic region of Q2

Published
2015

27. Bose–Einstein correlations in hadron-pairs from lepto-production on nuclei ranging from hydrogen to xenon

Author

Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Belostotski, S., Bianchi, N., Blok, H. P., Borissov, A., Bryzgalov, V., Burns, J., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Elbakian, G., Ellinghaus, F., Etzelmüller, E., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Gapienko, G., Gapienko, V., Garay García, J., Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, F., Gliske, S., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Imazu, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Lehmann, I., Lenisa, P., López Ruiz, A., Lorenzon, W., Lu, X.-G., Ma, B.-Q., Mahon, D., Makins, N. C. R., Mao, Y., Marianski, B., Martinez de la Ossa, A., Marukyan, H., Miyachi, Y., Movsisyan, A., Murray, M., Mussgiller, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W.-D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Schäfer, A., Schnell, G., Seitz, B., Shibata, T.-A., Shutov, V., Stahl, M., Stancari, M., Statera, M., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Ye, Z., Yen, S., Zihlmann, B., and Zupranski, P.

Subjects
INTERFERENCE, 67.85.Jk Other Bose-Einstein condensation phenomena, 13.60.-r Photon and charged-lepton interactions with hadrons, 24.10.Lx Monte Carlo simulations (including hadron and parton cascades and string breaking models), ENVIRONMENT, Physics and Astronomy (miscellaneous), Socio-culturale, INTERFEROMETRY, DEEP-INELASTIC SCATTERING, 13.60.-r Photon and charged-lepton interactions with hadrons, Economica, Physics and Astronomy, 67.85.Jk Other Bose-Einstein condensation phenomena, IDENTICAL PARTICLES, FRAGMENTATION, NEUTRINO, ANNIHILATION, HADRONIZATION, Nuclear Experiment, Engineering (miscellaneous), 24.10.Lx Monte Carlo simulations (including hadron and parton cascades and string breaking models), MULTIPLE PRODUCTION
Abstract

Bose–Einstein correlations of like-sign charged hadrons produced in deep-inelastic electron and positron scattering are studied in the HERMES experiment using nuclear targets of 1 H, 2 H, 3 He, 4 He, N, Ne, Kr, and Xe. A Gaussian approach is used to parametrize a two-particle correlation function determined from events with at least two charged hadrons of the same sign charge. This correlation function is compared to two different empirical distributions that do not include the Bose–Einstein correlations. One distribution is derived from unlike-sign hadron pairs, and the second is derived from mixing like-sign pairs from different events. The extraction procedure used simulations incorporating the experimental setup in order to correct the results for spectrometer acceptance effects, and was tested using the distribution of unlike-sign hadron pairs. Clear signals of Bose–Einstein correlations for all target nuclei without a significant variation with the nuclear target mass are found. Also, no evidence for a dependence on the invariant mass W of the photon-nucleon system is found when the results are compared to those of previous experiments.

Published
2015

28. High-pressure Brillouin and Raman spectroscopy of a natural antigorite single-crystal

Author

Marquardt, K., Marquardt, H., Speziale, S., Koch-Müller, M., Capitani, G., Marquardt, K, Marquardt, H, Speziale, S, Koch Müller, M, and Capitani, G

Subjects
Raman spectroscopy, Brillouin spectroscopy, Subduction zone processe, Elasticity, Antigorite, GEO/06 - MINERALOGIA
Abstract

Being the high-pressure polymorph of serpentine, antigorite is a candidate mineral to transport “water” into subduction zones. Its expected dehydration under elevated pressure-temperature conditions markedly influences physico-chemical properties and processes in these regions and is considered to trigger subduction zone seismicity. In order to map hydration in subduction zone environments, laboratory data on the (anisotropic) sound wave velocities of serpentine minerals are needed. Here, we present high-pressure acoustic wave velocities, measured within the a-c-plane of a natural antigorite singlecrystal by Brillouin scattering. Preparation of the desired sample for Brillouin Spectroscopy was possible by using the focused ion beam technique. The chosen crystallographic plane is representative of the expected preferred orientation of antigorite crystals in a subduction zone environment and, therefore, our results put direct constraints on the expected seismic anisotropy emerging from a crystallographic preferred orientation (CPO) of antigorite in these regions. In addition, we performed direction-dependent high-pressure Raman Spectroscopy of the same single-crystal. We find anomalies in the pressure dependencies of both acoustic wave velocities and measured Raman shifts at a pressure of around 7 GPa consistent with previous observations.

Published
2013

29. Bose–Einstein correlations in hadron-pairs from lepto-production on nuclei ranging from hydrogen to xenon

Author

Airapetian, A., Akopov, N., Blok, H. P., Statera, M., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Borissov, A., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Ye, Z., Yen, S., Zihlmann, B., Zupranski, P., HERMES Collaboration, Bryzgalov, V., Burns, J., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Akopov, Z., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Elbakian, G., Ellinghaus, F., Etzelmüller, E., Fabbri, R., Aschenauer, E. C., Fantoni, A., Felawka, L., Frullani, S., Gapienko, G., Gapienko, V., Garay Garcia, Jasone, Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, F., Augustyniak, W., Gliske, S., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Imazu, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Avakian, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Avetissian, A., Lehmann, I., Lenisa, P., Ruiz, A. López, Lorenzon, W., Lu, X. -G., Ma, B. -Q., Mahon, D., Makins, N. C. R., Mao, Y., Marianski, B., Avetisyan, E., Martinez de la Ossa, Alberto, Marukyan, H., Miyachi, Y., Movsisyan, A., Murray, M., Mussgiller, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Belostotski, S., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, Anush, Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Bianchi, N., Rubin, J., Ryckbosch, D., Salomatin, Y., Schäfer, A., Schnell, Gunar, Seitz, B., Shibata, T. -A., Shutov, V., Stahl, M., and Stancari, M.

Subjects
High Energy Physics - Experiment (hep-ex), FOS: Physical sciences, ddc:530, Nuclear Experiment (nucl-ex), Nuclear Experiment, High Energy Physics - Experiment
Abstract

Bose-Einstein correlations of like-sign charged hadrons produced in deep-inelastic electron and positron scattering are studied in the HERMES experiment using nuclear targets of $^1$H, $^2$H, $^3$He, $^4$He, N, Ne, Kr, and Xe. A Gaussian approach is used to parametrize a two-particle correlation function determined from events with at least two charged hadrons of the same sign charge. This correlation function is compared to two different empirical distributions that do not include the Bose-Einstein correlations. One distribution is derived from unlike-sign hadron pairs, and the second is derived from mixing like-sign pairs from different events. The extraction procedure used simulations incorporating the experimental setup in order to correct the results for spectrometer acceptance effects, and was tested using the distribution of unlike-sign hadron pairs. Clear signals of Bose-Einstein correlations for all target nuclei without a significant variation with the nuclear target mass are found. Also, no evidence for a dependence on the invariant mass $W$ of the photon-nucleon system is found when the results are compared to those of previous experiments.

Published
2015
Full Text
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30. Transverse-target-spin asymmetry in exclusive $��$-meson electroproduction

Author

The HERMES Collaboration, Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Avetissian, A., Belostotski, S., Blok, H. P., Borissov, A., Bryzgalov, V., Capitani, G. P., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., D��ren, M., Elbakian, G., Ellinghaus, F., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Gharibyan, V., Giordano, F., Gliske, S., Hasch, D., Hoek, M., Holler, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Krivokhijine, V. G., Lagamba, L., Lapik��s, L., Lehmann, I., Lenisa, P., Lorenzon, W., Ma, B. -Q., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Miyachi, Y., Movsisyan, A., Muccifora, V., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Schnell, G., Seitz, B., Shibata, T. -A., Statera, M., Steffens, E., Steijger, J. J. M., Stinzing, F., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Vikhrov, V., Vilardi, I., Vogel, C., Wang, S., Yaschenko, S., Yen, S., Zihlmann, B., and Zupranski, P.

Subjects
High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), Nuclear Theory, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment
Abstract

Hard exclusive electroproduction of $��$ mesons is studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target. The amplitudes of five azimuthal modulations of the single-spin asymmetry of the cross section with respect to the transverse proton polarization are measured. They are determined in the entire kinematic region as well as for two bins in photon virtuality and momentum transfer to the nucleon. Also, a separation of asymmetry amplitudes into longitudinal and transverse components is done. These results are compared to a phenomenological model that includes the pion pole contribution. Within this model, the data favor a positive $����$ transition form factor., DESY Report 15-149

Published
2015
Full Text
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31. Transverse-target-spin asymmetry in exclusive $\omega$-meson electroproduction

Author

Airapetian, A., Akopov, N., Capitani, G. P., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Akopov, Z., Elbakian, G., Ellinghaus, F., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Gharibyan, V., Giordano, F., Gliske, S., Aschenauer, E. C., Hasch, D., Hoek, M., Holler, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Augustyniak, W., Kisselev, A., Korotkov, V., Kozlov, V., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Lehmann, I., Lenisa, P., Lorenzon, W., Ma, B.-Q., Avetissian, A., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Miyachi, Y., Movsisyan, A., Muccifora, V., Naryshkin, Y., Nass, A., Negodaev, M., Belostotski, S., Nowak, W.-D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, Anush, Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Blok, H. P., Rubin, J., Ryckbosch, D., Salomatin, Y., Schnell, G., Seitz, B., Shibata, T.-A., Statera, M., Steffens, E., Steijger, J. J. M., Stinzing, F., Borissov, A., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Vikhrov, V., Vilardi, I., Vogel, C., Bryzgalov, V., Wang, S., Yaschenko, S., Yen, S., Zihlmann, B., Zupranski, P., HERMES Collaboration, and Student Lab and Education

Subjects
polarization [p], Leptroproduction, longitudinal, Nuclear Theory, Socio-culturale, HERMES, meson, High Energy Physics - Experiment, Economica, transition [form factor], Parton Distribution, Lepton Scattering, Leptroproduction, energy, QCS, ddc:530, SDG 7 - Affordable and Clean Energy, Nuclear Experiment, asymmetry [cross section], pole [pi], momentum transfer, scattering, photon, nucleon, electroproduction, beam [electron], Parton Distribution, angular dependence, High Energy Physics - Phenomenology, transverse, kinematics, target [hydrogen], positron, High Energy Physics::Experiment, Lepton Scattering, spectrometer, QCS, Particle Physics - Experiment, energy
Abstract

Hard exclusive electroproduction of $\omega$ mesons is studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target. The amplitudes of five azimuthal modulations of the single-spin asymmetry of the cross section with respect to the transverse proton polarization are measured. They are determined in the entire kinematic region as well as for two bins in photon virtuality and momentum transfer to the nucleon. Also, a separation of asymmetry amplitudes into longitudinal and transverse components is done. These results are compared to a phenomenological model that includes the pion pole contribution. Within this model, the data favor a positive $\pi\omega$ transition form factor., Comment: DESY Report 15-149

Published
2015
Full Text
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32. High-pressure Brillouin and Raman spectroscopy of a natural antigorite single-crystal

Author

Speziale, S., Marquardt, H., Koch-Müller, M., Marquardt, K., Capitani, G., Jahn, S., Wilke, M., Marquardt, H, Speziale, S, Koch Müller, M, Marquardt, K, Capitani, G, Jahn, S, and Wilke, M

Subjects
Raman spectroscopy, Brillouin spectroscopy, 550 - Earth sciences, Antigorite, GEO/06 - MINERALOGIA
Abstract

Being the high-pressure polymorph of serpentine, Antigorite is a candidate mineral to transport “water” into subduction zones. Its expected dehydration under elevated pressure-temperature conditions markedly influences physico-chemical properties and processes in these regions and is considered to trigger subduction zone seismicity. In order to map hydration in subduction zone environments, laboratory data on the (anisotropic) sound wave velocities of serpentine minerals are needed. Here, we present high-pressure acoustic wave velocities, measured within the a-c-plane of a natural antigorite single-crystal by Brillouin scattering. Preparation of the desired sample for Brillouin Spectroscopy was only possible by using the focused ion beam technique. The chosen crystallographic plane is representative of the expected preferred orientation of antigorite crystals in a subduction zone environment and, therefore, our results put direct constraints on the expected seismic anisotropy emerging from a crystallographic preferred orientation (CPO) of antigorite in these regions. In addition, we performed direction-dependent high-pressure Raman Spectroscopy of the same single-crystal. We find anomalies in the pressure dependencies of both acoustic wave velocities and measured Raman shifts at a pressure of around 7 GPa. This observation is consistent with previous Raman and x-ray diffraction studies and likely related to a stress-induced proton re-orientation.

Published
2012

35. Spin density matrix elements in exclusive ω electroproduction on 1 H and 2 H targets at 27.5 GeV beam energy

Author

Airapetian, A.II. Physikalisches Institut, Justus-Liebig Universität Gießen, 35392, Gießen, Germany, Akopov, N.(Yerevan Physics Institute, 375036, Yerevan, Armenia), Akopov, Z.(DESY, 22603, Hamburg, Germany), Augustyniak, W.(National Centre for Nuclear Research, 00-689, Warsaw, Poland), Avetissian, A.(Yerevan Physics Institute, 375036, Yerevan, Armenia), Blok, H. P.(National Institute for Subatomic Physics (Nikhef), 1009 DB, Amsterdam, The Netherlands), Borissov, A.(DESY, 22603, Hamburg, Germany), Bryzgalov, V.(Institute for High Energy Physics, 142281, Protvino, Moscow Region, Russia), Capiluppi, M.(Sezione di Ferrara, Istituto Nazionale di Fisica Nucleare, 44122, Ferrara, Italy), Capitani, G. P.(Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, 00044, Frascati, Italy), Cisbani, E.(Sezione di Roma, Gruppo Collegato Sanità, Istituto Nazionale di Fisica Nucleare, 00161, Rome, Italy), Ciullo, G.(Sezione di Ferrara, Istituto Nazionale di Fisica Nucleare, 44122, Ferrara, Italy), Contalbrigo, M.(Sezione di Ferrara, Istituto Nazionale di Fisica Nucleare, 44122, Ferrara, Italy), Dalpiaz, P. F.(Sezione di Ferrara, Istituto Nazionale di Fisica Nucleare, 44122, Ferrara, Italy), Deconinck, W.(DESY, 22603, Hamburg, Germany), De Leo, R.(Sezione di Bari, Istituto Nazionale di Fisica Nucleare, 70124, Bari, Italy), De Sanctis, E.(Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, 00044, Frascati, Italy), Diefenthaler, M.(Physikalisches Institut, Universität Erlangen-Nürnberg, 91058, Erlangen, Germany), Di Nezza, P.(Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, 00044, Frascati, Italy), Düren, M.(II. Physikalisches Institut, Justus-Liebig Universität Gießen, 35392, Gießen, Germany), Ehrenfried, M.(II. Physikalisches Institut, Justus-Liebig Universität Gießen, 35392, Gießen, Germany), Elbakian, G.(Yerevan Physics Institute, 375036, Yerevan, Armenia), Ellinghaus, F.(Nuclear Physics Laboratory, University of Colorado, 80309-0390, Boulder, CO, USA), Etzelmüller, E.(II. Physikalisches Institut, Justus-Liebig Universität Gießen, 35392, Gießen, Germany), Fabbri, R.(DESY, 15738, Zeuthen, Germany), Felawka, L.(TRIUMF, V6T 2A3, Vancouver, BC, Canada), Frullani, S.(Sezione di Roma, Gruppo Collegato Sanità, Istituto Nazionale di Fisica Nucleare, 00161, Rome, Italy), Gabbert, D.(DESY, 15738, Zeuthen, Germany), Gapienko, G.(Institute for High Energy Physics, 142281, Protvino, Moscow Region, Russia), Gapienko, V.(Institute for High Energy Physics, 142281, Protvino, Moscow Region, Russia), Garibaldi, F.(Sezione di Roma, Gruppo Collegato Sanità, Istituto Nazionale di Fisica Nucleare, 00161, Rome, Italy), Gavrilov, G.(DESY, 22603, Hamburg, Germany), Gharibyan, V.(Yerevan Physics Institute, 375036, Yerevan, Armenia), Hartig, M.(DESY, 22603, Hamburg, Germany), Hasch, D.(Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, 00044, Frascati, Italy), Holler, Y.(DESY, 22603, Hamburg, Germany), Hristova, I.(DESY, 15738, Zeuthen, Germany), Ivanilov, A.(Institute for High Energy Physics, 142281, Protvino, Moscow Region, Russia), Jackson, H. E.(Physics Division, Argonne National Laboratory, 60439-4843, Argonne, IL, USA), Joosten, S.(Department of Physics and Astronomy, Ghent University, 9000, Gent, Belgium), Kaiser, R.(SUPA, School of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK), Karyan, G.(Yerevan Physics Institute, 375036, Yerevan, Armenia), Keri, T.(II. Physikalisches Institut, Justus-Liebig Universität Gießen, 35392, Gießen, Germany), Kinney, E.(Nuclear Physics Laboratory, University of Colorado, 80309-0390, Boulder, CO, USA), Kisselev, A.(B.P. Konstantinov Petersburg Nuclear Physics Institute, 188300, Gatchina, Leningrad Region, Russia), Korotkov, V.(Institute for High Energy Physics, 142281, Protvino, Moscow Region, Russia), Kozlov, V.(Lebedev Physical Institute, 117924, Moscow, Russia), Kravchenko, P.(B.P. Konstantinov Petersburg Nuclear Physics Institute, 188300, Gatchina, Leningrad Region, Russia), Krivokhijine, V. G.(Joint Institute for Nuclear Research, 141980, Dubna, Russia), Lagamba, L.(Sezione di Bari, Istituto Nazionale di Fisica Nucleare, 70124, Bari, Italy), Lapikás, L.(National Institute for Subatomic Physics (Nikhef), 1009 DB, Amsterdam, The Netherlands), Lehmann, I.(SUPA, School of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK), Lenisa, P.(Sezione di Ferrara, Istituto Nazionale di Fisica Nucleare, 44122, Ferrara, Italy), Lorenzon, W.(Randall Laboratory of Physics, University of Michigan, 48109-1040, Ann Arbor, MI, USA), Ma, B.-Q.(School of Physics, Peking University, 100871, Beijing, China), Mahon, D.(SUPA, School of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK), Manaenkov, S. I.(B.P. Konstantinov Petersburg Nuclear Physics Institute, 188300, Gatchina, Leningrad Region, Russia), Mao, Y.(School of Physics, Peking University, 100871, Beijing, China), Marianski, B.(National Centre for Nuclear Research, 00-689, Warsaw, Poland), Marukyan, H.(Yerevan Physics Institute, 375036, Yerevan, Armenia), Movsisyan, A.(Sezione di Ferrara, Istituto Nazionale di Fisica Nucleare, 44122, Ferrara, Italy), Murray, M.(SUPA, School of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK), Naryshkin, Y.(B.P. Konstantinov Petersburg Nuclear Physics Institute, 188300, Gatchina, Leningrad Region, Russia), Nass, A.(Physikalisches Institut, Universität Erlangen-Nürnberg, 91058, Erlangen, Germany), Nowak, W.-D.(DESY, 15738, Zeuthen, Germany), Pappalardo, L. L.(Sezione di Ferrara, Istituto Nazionale di Fisica Nucleare, 44122, Ferrara, Italy), Perez-Benito, R.(II. Physikalisches Institut, Justus-Liebig Universität Gießen, 35392, Gießen, Germany), Petrosyan, A.(Yerevan Physics Institute, 375036, Yerevan, Armenia), Reimer, P. E.(Physics Division, Argonne National Laboratory, 60439-4843, Argonne, IL, USA), Reolon, A. R.(Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, 00044, Frascati, Italy), Riedl, C.(DESY, 15738, Zeuthen, Germany), Rith, K.(Physikalisches Institut, Universität Erlangen-Nürnberg, 91058, Erlangen, Germany), Rostomyan, A.(DESY, 22603, Hamburg, Germany), Ryckbosch, D.(Department of Physics and Astronomy, Ghent University, 9000, Gent, Belgium), Schäfer, A.(Institut für Theoretische Physik, Universität Regensburg, 93040, Regensburg, Germany), Schnell, G.(Department of Theoretical Physics, University of the Basque Country UPV/EHU, 48080, Bilbao, Spain), Schüler, K. P.(DESY, 22603, Hamburg, Germany), Seitz, B.(SUPA, School of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK), Shibata, T.-A.(Department of Physics, Tokyo Institute of Technology, 152, Tokyo, Japan), Stahl, M.(II. Physikalisches Institut, Justus-Liebig Universität Gießen, 35392, Gießen, Germany), Stancari, M.(Sezione di Ferrara, Istituto Nazionale di Fisica Nucleare, 44122, Ferrara, Italy), Statera, M.(Sezione di Ferrara, Istituto Nazionale di Fisica Nucleare, 44122, Ferrara, Italy), Steffens, E.(Physikalisches Institut, Universität Erlangen-Nürnberg, 91058, Erlangen, Germany), Steijger, J. J. M.(National Institute for Subatomic Physics (Nikhef), 1009 DB, Amsterdam, The Netherlands), Taroian, S.(Yerevan Physics Institute, 375036, Yerevan, Armenia), Terkulov, A.(Lebedev Physical Institute, 117924, Moscow, Russia), Truty, R.(Department of Physics, University of Illinois, 61801-3080, Urbana, IL, USA), Trzcinski, A.(National Centre for Nuclear Research, 00-689, Warsaw, Poland), Tytgat, M.(Department of Physics and Astronomy, Ghent University, 9000, Gent, Belgium), Van Haarlem, Y.(Department of Physics and Astronomy, Ghent University, 9000, Gent, Belgium), Van Hulse, C.(Department of Theoretical Physics, University of the Basque Country UPV/EHU, 48080, Bilbao, Spain), Vikhrov, V.(B.P. Konstantinov Petersburg Nuclear Physics Institute, 188300, Gatchina, Leningrad Region, Russia), Vilardi, I.(Sezione di Bari, Istituto Nazionale di Fisica Nucleare, 70124, Bari, Italy), Wang, S.(School of Physics, Peking University, 100871, Beijing, China), Yaschenko, S.(DESY, 22603, Hamburg, Germany), Yen, S.(TRIUMF, V6T 2A3, Vancouver, BC, Canada), Zeiler, D.(Physikalisches Institut, Universität Erlangen-Nürnberg, 91058, Erlangen, Germany), Zihlmann, B.(DESY, 22603, Hamburg, Germany), and Zupranski, P.(National Centre for Nuclear Research, 00-689, Warsaw, Poland)

Abstract

Exclusive electroproduction of ω mesons on unpolarized hydrogen and deuterium targets is studied in the kinematic region of Q2>1.0 GeV 2 , 3.0 GeV

Published
2014

36. A PDB-wide, evolution-based assessment of protein-protein interfaces

Author

Baskaran K, Jose Manuel Duarte, Biyani N, Bliven S, and Capitani G

Subjects
Models, Molecular, Crystal contacts, PDB, PISA, Computational Biology, Proteins, Protein Structure, Secondary, Protein–protein interfaces, Biological interfaces, Structural Biology, EPPIC, Amino Acid Sequence, Databases, Protein, Conserved Sequence, Protein Binding, Research Article
Abstract

Background Thanks to the growth in sequence and structure databases, more than 50 million sequences are now available in UniProt and 100,000 structures in the PDB. Rich information about protein–protein interfaces can be obtained by a comprehensive study of protein contacts in the PDB, their sequence conservation and geometric features. Results An automated computational pipeline was developed to run our Evolutionary Protein–Protein Interface Classifier (EPPIC) software on the entire PDB and store the results in a relational database, currently containing > 800,000 interfaces. This allows the analysis of interface data on a PDB-wide scale. Two large benchmark datasets of biological interfaces and crystal contacts, each containing about 3000 entries, were automatically generated based on criteria thought to be strong indicators of interface type. The BioMany set of biological interfaces includes NMR dimers solved as crystal structures and interfaces that are preserved across diverse crystal forms, as catalogued by the Protein Common Interface Database (ProtCID) from Xu and Dunbrack. The second dataset, XtalMany, is derived from interfaces that would lead to infinite assemblies and are therefore crystal contacts. BioMany and XtalMany were used to benchmark the EPPIC approach. The performance of EPPIC was also compared to classifications from the Protein Interfaces, Surfaces, and Assemblies (PISA) program on a PDB-wide scale, finding that the two approaches give the same call in about 88% of PDB interfaces. By comparing our safest predictions to the PDB author annotations, we provide a lower-bound estimate of the error rate of biological unit annotations in the PDB. Additionally, we developed a PyMOL plugin for direct download and easy visualization of EPPIC interfaces for any PDB entry. Both the datasets and the PyMOL plugin are available at http://www.eppic-web.org/ewui/#downloads. Conclusions Our computational pipeline allows us to analyze protein–protein contacts and their sequence conservation across the entire PDB. Two new benchmark datasets are provided, which are over an order of magnitude larger than existing manually curated ones. These tools enable the comprehensive study of several aspects of protein–protein contacts in the PDB and represent a basis for future, even larger scale studies of protein–protein interactions.

Published
2014

37. Spin density matrix elements in exclusive $\omega$ electroproduction on $^1$H and $^2$H targets at 27.5 GeV beam energy

Author

The HERMES Collaboration, Airapetian, A., Akopov, N., Akopov, Z., Augustyniak, W., Avetissian, A., Blok, H. P., Borissov, A., Bryzgalov, V., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Etzelmüller, E., Fabbri, R., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Lehmann, I., Lenisa, P., Lorenzon, W., Ma, B. -Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Movsisyan, A., Murray, M., Naryshkin, Y., Nass, A., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rostomyan, A., Ryckbosch, D., Schäfer, A., Schnell, G., Schüler, K. P., Seitz, B., Shibata, T. -A., Stahl, M., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Yen, S., Zeiler, D., Zihlmann, B., and Zupranski, P.

Subjects
High Energy Physics - Phenomenology, High Energy Physics::Experiment, Nuclear Experiment, High Energy Physics - Experiment
Abstract

Exclusive electroproduction of $\omega$ mesons on unpolarized hydrogen and deuterium targets is studied in the kinematic region of Q$^2$>1.0 GeV$^2$, 3.0 GeV < W < 6.3 GeV, and -t'< 0.2 GeV$^2$. Results on the angular distribution of the $\omega$ meson, including its decay products, are presented. The data were accumulated with the HERMES forward spectrometer during the 1996-2007 running period using the 27.6 GeV longitudinally polarized electron or positron beam of HERA. The determination of the virtual-photon longitudinal-to-transverse cross-section ratio reveals that a considerable part of the cross section arises from transversely polarized photons. Spin density matrix elements are presented in projections of Q$^2$ or -t'. Violation of s-channel helicity conservation is observed for some of these elements. A sizable contribution from unnatural-parity-exchange amplitudes is found and the phase shift between those amplitudes that describe transverse $\omega$ production by longitudinal and transverse virtual photons, $\gamma^{*}_{L} \to \omega_{T}$ and $\gamma^{*}_{T} \to \omega_{T}$, is determined for the first time. A hierarchy of helicity amplitudes is established, which mainly means that the unnatural-parity-exchange amplitude describing the $\gamma^*_T \to \omega_T$ transition dominates over the two natural-parity-exchange amplitudes describing the $\gamma^*_L \to \omega_L$ and $\gamma^*_T \to \omega_T$ transitions, with the latter two being of similar magnitude. Good agreement is found between the HERMES proton data and results of a pQCD-inspired phenomenological model that includes pion-pole contributions, which are of unnatural parity., Comment: "Erratum version", e.g., includes the corrected version of Figure 6, to be published in "Erratum to: Spin density matrix elements in exclusive omega electroproduction on 1H and 2H targets at 27.5 GeV beam energy". Three SDMEs were mislabeled in the figure of the previously published version [EPJC74(2014)3110]. The labels have been fixed, while none of the results or conclusions changed

Published
2014

38. Transverse target single-spin asymmetry in inclusive electroproduction of charged pions and kaons

Author

Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Avetissian, A., Avetisyan, E., Belostotski, S., Blok, H. P., Borissov, A., Bryzgalov, V., Burns, J., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Etzelmüller, E., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garay García, J., Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, F., Gliske, S., Hartig, M., Hasch, D., Hoek, M., Holler, Y., Hristova, I., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Lehmann, I., Lenisa, P., Lorenzon, W., Lu, X.-G., Ma, B.-Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Miyachi, Y., Movsisyan, A., Muccifora, V., Murray, M., Mussgiller, A., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W.-D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Schäfer, A., Schnell, G., Seitz, B., Shibata, T.-A., Stahl, M., Statera, M., Steffens, E., Steijger, J. J. M., Stinzing, F., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Vogel, C., Wang, S., Yaschenko, S., Ye, Z., Yen, S., Zihlmann, B., and Zupranski, P.

Abstract

Single-spin asymmetries were investigated in inclusive electroproduction of charged pions and kaons\ud from transversely polarized protons at the Hermes experiment. The asymmetries were studied as a\ud function of the azimuthal angle ψ about the beam direction between the target-spin direction and the hadron production plane, the transverse hadron momentum PT relative to the direction of the incident beam, and the Feynman variable xF . The sinψ amplitudes are positive for π+ and K+, slightly negative for π− and consistent with zero for K−, with particular PT but weak xF dependences. Especially large asymmetries are observed for two small subsamples of events, where also the scattered electron was recorded by the spectrometer.

Published
2014

39. Spin density matrix elements in exclusive $\omega$ electroproduction on $\mathrm{^1 H}$ and $\mathrm{^2 H}$ targets at 27.5 GeV beam energy

Author

Airapetian, Avetik, Akopov, N., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Akopov, Zaven, Ehrenfried, M., Elbakian, G., Ellinghaus, F., Etzelmüller, E., Fabbri, R., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Augustyniak, W., Garibaldi, F., Gavrilov, G., Gharibyan, V., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Ivanilov, A., Jackson, H. E., Joosten, S., Avetissian, A., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Blok, H. P., Lapikás, L., Lehmann, I., Lenisa, P., Lorenzon, W., Ma, B. -Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Borissov, A., Movsisyan, A., Murray, M., Naryshkin, Y., Nass, A., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, Anush, Reimer, P. E., Reolon, A. R., Bryzgalov, V., Riedl, C., Rith, K., Rostomyan, A., Ryckbosch, D., Schäfer, A., Schnell, Gunar, Schüler, K. P., Seitz, B., Shibata, T. -A., Stahl, M., Capiluppi, M., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Capitani, G. P., Van Hulse, C., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Yen, S., Zeiler, D., Zihlmann, B., Zupranski, P., and HERMES Collaboration

Subjects
perturbation theory [quantum chromodynamics], 27.6 GeV, amplitude analysis [helicity], High Energy Physics::Phenomenology, electroproduction [omega(783)], pole [pi], density matrix [spin], HERMES, exclusive reaction [positron p], exclusive reaction [electron p], transverse [cross section], DESY HERA Stor, exclusive reaction [electron deuteron], High Energy Physics::Experiment, ddc:530, angular distribution, ratio [cross section], Nuclear Experiment, longitudinal [cross section], longitudinal [polarized beam], experimental results
Abstract

Exclusive electroproduction of $\omega $ mesons on unpolarized hydrogen and deuterium targets is studied in the kinematic region of $Q^2> 1.0$ GeV$^2$ , 3.0 GeV $< W

Published
2014
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40. Pentaquark $��^+$ search at HERMES

Author

The HERMES Collaboration, Akopov, N., Akopov, Z., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Belostotski, S., Blok, H. P., Borissov, A., Bowles, J., Bryzgalov, V., Burns, J., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Di Nezza, P., Elbakian, G., Etzelm��ller, E., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Gabbert, D., Garc��a, J. Garay, Garibaldi, F., Gavrilov, G., Giordano, F., Gliske, S., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Imazu, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapik��s, L., Lehmann, I., Ruiz, A. L��pez, Lorenzon, W., Lu, X., Ma, B. -Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., de la Ossa, A. Martinez, Marukyan, H., Miller, C. A., Miyachi, Y., Movsisyan, A., Murray, M., Nappi, E., Nass, A., Negodaev, M., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Schnell, G., Sch��ler, K. P., Seitz, B., Shibata, T. -A., Stancari, M., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Ye, H., Ye, Z., Yen, S., Zihlmann, B., and Zupranski, P.

Subjects
High Energy Physics - Experiment (hep-ex), FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment
Abstract

The earlier search at HERMES for narrow baryon states excited in quasi-real photoproduction, decaying through the channel $pK_S^0\rightarrow p��^+��^-$, has been extended with improved decay-particle reconstruction, more advanced particle identification, and increased event samples. The structure observed earlier at an invariant mass of 1528 MeV shifts to 1522 MeV and the statistical significance drops to about 2$��$ for data taken with a deuterium target. The number of events above background is $68_{-31}^{+98}\text{(stat)}\pm13\text{(sys)}$. No such structure is observed in the hydrogen data set.

Published
2014
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41. Transverse polarization of $��$ hyperons from quasireal photoproduction on nuclei

Author

The HERMES Collaboration, Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Belostotski, S., Bianchi, N., Blok, H. P., Borissov, A., Bowles, J., Brodski, I., Bryzgalov, V., Burns, J., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Nardo, L., De Sanctis, E., Diefenthaler, M., Di Nezza, P., D��ren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, F., Gliske, S., Golembiovskaya, M., Hadjidakis, C., Hartig, M., Hasch, D., Hillenbrand, A., Hoek, M., Holler, Y., Hristova, I., Imazu, Y., Ivanilov, A., Jackson, H. E., Jo, H. S., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Kobayashi, N., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapik��s, L., Lehmann, I., Lenisa, P., Ruiz, A. L��pez, Lorenzon, W., Lu, X. -G., Ma, B. -Q., Mahon, D., Makins, N. C. R., Manaenkov, S. I., Mao, Y., Marianski, B., de la Ossa, A. Martinez, Marukyan, H., Miller, C. A., Miyachi, Y., Movsisyan, A., Muccifora, V., Murray, M., Mussgiller, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanftl, F., Sch��fer, A., Schnell, G., Sch��ler, K. P., Seitz, B., Shibata, T. -A., Shutov, V., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stewart, J., Stinzing, F., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Vandenbroucke, A., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Ye, Z., Yu, W., Zagrebelnyy, V., Zeiler, D., Zihlmann, B., and Zupranski, P.

Subjects
High Energy Physics - Experiment (hep-ex), High Energy Physics::Phenomenology, Nuclear Theory, Physics::Atomic and Molecular Clusters, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

The transverse polarization of $��$ hyperons was measured in inclusive quasireal photoproduction for various target nuclei ranging from hydrogen to xenon. The data were obtained by the HERMES experiment at HERA using the 27.6 GeV lepton beam and nuclear gas targets internal to the lepton storage ring. The polarization observed is positive for light target nuclei and is compatible with zero for krypton and xenon., final version to be published in Phys. Rev. D (in press)

Published
2014
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43. Pentaquark $\Theta^+$ search at HERMES

Author

The HERMES Collaboration, Akopov, N., Akopov, Z., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Belostotski, S., Blok, H. P., Borissov, A., Bowles, J., Bryzgalov, V., Burns, J., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Di Nezza, P., Elbakian, G., Etzelmüller, E., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Gabbert, D., García, J. Garay, Garibaldi, F., Gavrilov, G., Giordano, F., Gliske, S., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Imazu, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Lehmann, I., Ruiz, A. López, Lorenzon, W., Lu, X., Ma, B. -Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., de la Ossa, A. Martinez, Marukyan, H., Miller, C. A., Miyachi, Y., Movsisyan, A., Murray, M., Nappi, E., Nass, A., Negodaev, M., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Schnell, G., Schüler, K. P., Seitz, B., Shibata, T. -A., Stancari, M., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Ye, H., Ye, Z., Yen, S., Zihlmann, B., and Zupranski, P.

Subjects
polarized target [deuterium], HERMES, photoproduction [hadron], High Energy Physics - Experiment, target [deuterium], ddc:530, Nuclear Experiment, pentaquark, hadronic decay [Theta(1540)], 27.6 GeV, background, polarized target [hydrogen], +p+K0%28S%29%22">Theta(1540) --> p K0(S), +pi%2B+pi%22">K0(S) --> pi+ pi, baryon, DESY HERA Stor, (p K0(S)) [mass spectrum], search for [pentaquark], hydrogen, deep inelastic scattering [electron p], High Energy Physics::Experiment, deep inelastic scattering [electron deuteron], particle identification, statistical, experimental results, photoproduction
Abstract

The earlier search at HERMES for narrow baryon states excited in quasi-real photoproduction, decaying through the channel $pK_S^0\rightarrow p\pi^+\pi^-$, has been extended with improved decay-particle reconstruction, more advanced particle identification, and increased event samples. The structure observed earlier at an invariant mass of 1528 MeV shifts to 1522 MeV and the statistical significance drops to about 2$\sigma$ for data taken with a deuterium target. The number of events above background is $68_{-31}^{+98}\text{(stat)}\pm13\text{(sys)}$. No such structure is observed in the hydrogen data set.

Published
2014
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44. Spin density matrix elements in exclusive $��$ electroproduction on $^1$H and $^2$H targets at 27.5 GeV beam energy

Author

The HERMES Collaboration, Airapetian, A., Akopov, N., Akopov, Z., Augustyniak, W., Avetissian, A., Blok, H. P., Borissov, A., Bryzgalov, V., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., D��ren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Etzelm��ller, E., Fabbri, R., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapik��s, L., Lehmann, I., Lenisa, P., Lorenzon, W., Ma, B. -Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Movsisyan, A., Murray, M., Naryshkin, Y., Nass, A., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rostomyan, A., Ryckbosch, D., Sch��fer, A., Schnell, G., Sch��ler, K. P., Seitz, B., Shibata, T. -A., Stahl, M., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Yen, S., Zeiler, D., Zihlmann, B., and Zupranski, P.

Subjects
High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment
Abstract

Exclusive electroproduction of $��$ mesons on unpolarized hydrogen and deuterium targets is studied in the kinematic region of Q$^2$>1.0 GeV$^2$, 3.0 GeV < W < 6.3 GeV, and -t'< 0.2 GeV$^2$. Results on the angular distribution of the $��$ meson, including its decay products, are presented. The data were accumulated with the HERMES forward spectrometer during the 1996-2007 running period using the 27.6 GeV longitudinally polarized electron or positron beam of HERA. The determination of the virtual-photon longitudinal-to-transverse cross-section ratio reveals that a considerable part of the cross section arises from transversely polarized photons. Spin density matrix elements are presented in projections of Q$^2$ or -t'. Violation of s-channel helicity conservation is observed for some of these elements. A sizable contribution from unnatural-parity-exchange amplitudes is found and the phase shift between those amplitudes that describe transverse $��$ production by longitudinal and transverse virtual photons, $��^{*}_{L} \to ��_{T}$ and $��^{*}_{T} \to ��_{T}$, is determined for the first time. A hierarchy of helicity amplitudes is established, which mainly means that the unnatural-parity-exchange amplitude describing the $��^*_T \to ��_T$ transition dominates over the two natural-parity-exchange amplitudes describing the $��^*_L \to ��_L$ and $��^*_T \to ��_T$ transitions, with the latter two being of similar magnitude. Good agreement is found between the HERMES proton data and results of a pQCD-inspired phenomenological model that includes pion-pole contributions, which are of unnatural parity., "Erratum version", e.g., includes the corrected version of Figure 6, to be published in "Erratum to: Spin density matrix elements in exclusive omega electroproduction on 1H and 2H targets at 27.5 GeV beam energy". Three SDMEs were mislabeled in the figure of the previously published version [EPJC74(2014)3110]. The labels have been fixed, while none of the results or conclusions changed

Published
2014
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45. Spin density matrix elements in exclusive omega electroproduction on H-1 and H-2 targets at 27.5 GeV beam energy

Author

Airapetian, A., Akopov, N., Akopov, Z., Augustyniak, W., Avetissian, A., Blok, H. P., Borissov, A., Bryzgalov, V., Capiluppi, Marco, Capitani, G. P., Cisbani, E., Ciullo, Giuseppe, Contalbrigo, Marco, Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Etzelmüller, E., Fabbri, R., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Lehmann, I., Lenisa, Paolo, Lorenzon, W., B. Q., Ma, Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Movsisyan, A., Murray, M., Naryshkin, Y., Nass, A., Nowak, W. D., Pappalardo, Luciano Libero, Perez Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rostomyan, A., Ryckbosch, D., Schäfer, A., Schnell, G., Schüler, K. P., Seitz, B., Shibata, T. A., Stahl, M., Stancari, Michelle Dawn, Statera, Marco, Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Yen, S., Zeiler, D., Zihlmann, B., and Zupranski, P.

Subjects
13.60.-r Photon and charged-lepton interactions with hadrons, 29.27.Hj Polarized beams, 13.60.-r Photon and charged-lepton interactions with hadrons, 34.80.Nz Spin dependence of cross sections, polarized beam experiments, 29.27.Hj Polarized beams, 34.80.Nz Spin dependence of cross sections, NO
Published
2014

46. Spin density matrix elements in exclusive $\omega$ electroproduction on $\mathrm{^1 H}$ and $\mathrm{^2 H}$ targets at 27.5 GeV beam energy

Author

Airapetian, Avetik, Akopov, N., Akopov, Zaven, Augustyniak, W., Avetissian, A., Blok, H. P., Borissov, A., Bryzgalov, V., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Etzelmüller, E., Fabbri, R., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Lehmann, I., Lenisa, P., Lorenzon, W., Ma, B. -Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Movsisyan, A., Murray, M., Naryshkin, Y., Nass, A., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, Anush, Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rostomyan, A., Ryckbosch, D., Schäfer, A., Schnell, Gunar, Schüler, K. P., Seitz, B., Shibata, T. -A., Stahl, M., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Yen, S., Zeiler, D., Zihlmann, B., and Zupranski, P.

Subjects
27.6 GeV, electron deuteron: exclusive reaction, cross section: longitudinal, cross section: ratio, HERMES, omega(783): electroproduction, cross section: transverse, DESY HERA Stor, pi: pole, positron p: exclusive reaction, electron p: exclusive reaction, polarized beam: longitudinal, angular distribution, spin: density matrix, quantum chromodynamics: perturbation theory, helicity: amplitude analysis, experimental results
Abstract

The European physical journal / C 74(11), 3110 (2014). doi:10.1140/epjc/s10052-014-3110-1, Exclusive electroproduction of $\omega $ mesons on unpolarized hydrogen and deuterium targets is studied in the kinematic region of $Q^2> 1.0$ GeV$^2$ , 3.0 GeV $< W, Published by Springer, Berlin

Published
2014
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47. Spin density matrix elements in exclusive $\omega$ electroproduction on $\mathrm{^1 H}$ and $\mathrm{^2 H}$ targets at 27.5 GeV beam energy

Author

Airapetian, Avetik, Akopov, N., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Akopov, Z., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Etzelmüller, E., Fabbri, R., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Augustyniak, W., Garibaldi, F., Gavrilov, G., Gharibyan, V., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Ivanilov, A., Jackson, H. E., Joosten, S., Avetissian, A., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Blok, H. P., Lapikás, L., Lehmann, I., Lenisa, P., Lorenzon, W., Ma, B. -Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Borissov, A., Movsisyan, A., Murray, M., Naryshkin, Y., Nass, A., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, Anush, Reimer, P. E., Reolon, A. R., Bryzgalov, V., Riedl, C., Rith, K., Rostomyan, A., Ryckbosch, D., Schäfer, A., Schnell, Gunar, Schüler, K. P., Seitz, B., Shibata, T. -A., Stahl, M., Capiluppi, M., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Capitani, G. P., Van Hulse, C., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Yen, S., Zeiler, D., Zihlmann, B., Zupranski, P., and HERMES Collaboration

Subjects
perturbation theory [quantum chromodynamics], 27.6 GeV, amplitude analysis [helicity], High Energy Physics::Phenomenology, electroproduction [omega(783)], pole [pi], density matrix [spin], HERMES, exclusive reaction [positron p], exclusive reaction [electron p], transverse [cross section], DESY HERA Stor, exclusive reaction [electron deuteron], High Energy Physics::Experiment, ddc:530, angular distribution, ratio [cross section], Nuclear Experiment, longitudinal [cross section], longitudinal [polarized beam], experimental results
Abstract

Exclusive electroproduction of $\omega $ mesons on unpolarized hydrogen and deuterium targets is studied in the kinematic region of $Q^2> 1.0$ GeV$^2$ , 3.0 GeV $< W

Published
2014

49. Evidence for a single-spin azimuthal asymmetry in semi-inclusive pion electroproduction

Author

Airapetian, A., Akopov, N., Beckmann, M., Krivokhijine, V. G., Kurisuno, M., Kyle, G., Lachnit, W., Lenisa, P., Lorenzon, W., Makins, N. C. R., Martens, F. K., Martin, J. W., Masoli, F., Belostotski, S., Mateos, A., McAndrew, M., McIlhany, K., McKeown, R. D., Meissner, F., Menden, F., Metz, A., Meyners, N., Mikloukho, O., Miller, C. A., Belz, J. E., Miller, M. A., Milner, R., Most, A., Muccifora, V., Mussa, R., Nagaitsev, A., Naryshkin, Y., Nathan, A. M., Neunreither, F., Niczyporuk, M., Benisch, Th., Nowak, W.-D., Nupieri, M., Oganessyan, K. A., O'Neill, T. G., Openshaw, R., Ouyang, J., Owen, B. R., Papavassiliou, V., Pate, S. F., Pitt, M., Bernreuther, S., Potashov, S., Potterveld, D. H., Rakness, G., Reali, A., Redwine, R., Reolon, A. R., Ristinen, R., Rith, K., Rossi, P., Rudnitsky, S., Bianchi, N., Ruh, M., Ryckbosch, D., Sakemi, Y., Savin, I., Scarlett, C., Schäfer, A., Schmidt, F., Schmitt, H., Schnell, G., Schüler, K. P., Blouw, J., Schwind, A., Seibert, J., Shibata, T.-A., Shibatani, K., Shin, T., Shutov, V., Simani, C., Simon, A., Sinram, K., Slavich, P., Böttcher, H., Spengos, M., Steffens, E., Stenger, J., Stewart, J., Stoesslein, U., Sutter, M., Tallini, H., Taroian, S., Terkulov, A., Teryaev, O., Borissov, A., Thomas, E., Tipton, B., Tytgat, M., Urciuoli, G. M., van den Brand, J. F. J., van der Steenhoven, G., van de Vyver, R., van Hunen, J. J., Vetterli, M. C., Vikhrov, V., Bouwhuis, M., Vincter, M. G., Visser, J., Volk, E., Wander, W., Wendland, J., Williamson, S. E., Wise, T., Woller, K., Yoneyama, S., Zohrabian, H., Amarian, M., Brack, J., HERMES Collaboration, Brauksiepe, S., Braun, B., Bray, B., Brons, St., Brückner, W., Brüll, A., Bruins, E. E. W., Bulten, H. J., Capitani, G. P., Aschenauer, E. C., Carter, P., Chumney, P., Cisbani, E., Court, G. R., Dalpiaz, P. F., De Sanctis, E., De Schepper, D., Devitsin, E., de Witt Huberts, P. K. A., Di Nezza, P., Avakian, H., Düren, M., Dvoredsky, A., Elbakian, G., Ely, J., Fantoni, A., Fechtchenko, A., Ferstl, M., Fiedler, K., Filippone, B. W., Fischer, H., Avakian, R., Fox, B., Franz, J., Frullani, S., Funk, M.-A., Gärber, Y., Gao, H., Garibaldi, F., Gavrilov, G., Geiger, P., Gharibyan, V., Avetissian, A., Golendukhin, A., Graw, G., Grebeniouk, O., Green, P. W., Greeniaus, L. G., Grosshauser, C., Guidal, M., Gute, A., Gyurjyan, V., Haas, J. P., Avetissian, E., Haeberli, W., Hansen, J.-O., Hartig, M., Hasch, D., Häusser, O., Heinsius, F. H., Henderson, R., Henoch, M., Hertenberger, R., Holler, Y., Bains, B., Holt, R. J., Hoprich, W., Ihssen, H., Iodice, M., Izotov, A., Jackson, H. E., Jgoun, A., Kaiser, R., Kinney, E., Kisselev, A., Baumgarten, C., Kitching, P., Kobayashi, H., Koch, N., Königsmann, K., Kolstein, M., Kolster, H., Korotkov, V., Korsch, W., Kozlov, V., Kramer, L. H., and (Astro)-Particles Physics

Subjects
Quark, Particle physics, Proton structure, FRAGMENTATION FUNCTIONS, media_common.quotation_subject, General Physics and Astronomy, BEAM, NUCLEONS, 01 natural sciences, Asymmetry, Nuclear physics, Pion, LEPTOPRODUCTION, 0103 physical sciences, ddc:550, DISTRIBUTIONS, Nuclear Experiment, 010306 general physics, media_common, Physics, 010308 nuclear & particles physics, Scattering, polarized target internal, Deep inelastic scattering, Transverse plane, Distribution function, ANALYZING POWER, High Energy Physics::Experiment, Lepton
Abstract

Single-spin asymmetries for semi-inclusive pion production in deep-inelastic scattering have been measured for the first time. A significant target-spin asymmetry of the distribution in the azimuthal angle straight phi of the pion relative to the lepton scattering plane was formed for pi(+) electroproduction on a longitudinally polarized hydrogen target. The corresponding analyzing power in the sinstraight phi moment of the cross section is 0.022+/-0.005+/-0.003. This result can be interpreted as the effect of terms in the cross section involving chiral-odd spin distribution functions in combination with a chiral-odd fragmentation function that is sensitive to the transverse polarization of the fragmenting quark.

Published
2000
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