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24 results on '"Capitani G."'

1. 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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2. 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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3. 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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4. 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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5. 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

6. Beam-helicity asymmetry in associated electroproduction of real photons $ep \to e\gamma \pi N$ in the $\Delta$-resonance region

Author

The HERMES Collaboration, Airapetian, A., Akopov, N., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Blok, H. P., Böttcher, H., Borissov, A., Bowles, J., Brodski, I., Bryzgalov, V., Burns, J., 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., Frullani, S., Gapienko, G., Gapienko, V., García, J. Garay, Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, F., Gliske, S., 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., Lu, X. -G., Ma, B. -Q., Mahon, D., Makins, N. C. R., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Miller, C. A., 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., Stewart, J., Stinzing, F., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Ye, Z., Yen, S., Zagrebelnyy, V., Zihlmann, B., and Zupranski, P.

Subjects
internal [target], 27.6 GeV, +nucleon+pi+electron+photon%22">positron p --> nucleon pi electron photon, scattering amplitude, HERMES, asymmetry [helicity], Delta(1232), High Energy Physics - Experiment, DESY HERA Stor, associated production [photon], interaction [positron p], Physics::Accelerator Physics, ddc:530, High Energy Physics::Experiment, Nuclear Experiment, longitudinal [polarized beam], electroproduction [pi], recoil [detector], experimental results
Abstract

The beam-helicity asymmetry in associated electroproduction of real photons, $ep\to e\gamma \pi N$, in the $\Delta$(1232)-resonance region is measured using the longitudinally polarized HERA positron beam and an unpolarized hydrogen target. Azimuthal Fourier amplitudes of this asymmetry are extracted separately for two channels, $ep\to e\gamma \pi^0 p$ and $ep\to e\gamma \pi^+ n$, from a data set collected with a recoil detector. All asymmetry amplitudes are found to be consistent with zero., Comment: 17 pages, 4 figures, (minor changes wit respect to previous arXiv version)

Published
2013
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7. Transverse Polarization of Lambda and Lambda-bar Hyperons in Quasi-Real Photon-Nucleon Scattering at HERMES

Author

Airapetian, A., Akopov, N., Avetissian, E., Mikloukho, O., Miller, C. A., Miyachi, Y., Muccifora, V., Nagaitsev, A., Nappi, E., Naryshkin, Y., Nass, A., Nowak, W.-D., Oganessyan, K., Bailey, P., Ohsuga, H., Orlandi, G., Potashov, S., Potterveld, D. H., Raithel, M., Reggiani, D., Reimer, P. E., Reischl, A., Reolon, A. R., Rith, K., Baturin, V., Rosner, G., Rostomyan, A., Ryckbosch, D., Sanjiev, I., Savin, I., Scarlett, C., Schafer, A., Schill, C., Schnell, G., Schuler, K. P., Baumgarten, C., Schwind, A., Seibert, J., Seitz, B., Shanidze, R., Shibata, T.-A., Shutov, V., Simani, M. C., Sinram, K., Stancari, M., Statera, M., Beckmann, M., Steffens, E., Steijger, J. J. M., Stewart, J., Stosslein, U., Tanaka, H., Taroian, S., Tchuiko, B., Terkulov, A., Tessarin, S., Thomas, E., Belostotski, S., Tkabladze, A., Trzcinski, A., Tytgat, M., Urciuoli, G. M., van der Nat, P. B., van der Steenhoven, G., van de Vyver, R., Veretennikov, D., Vetterli, M. C., Vikhrov, V., Bernreuther, S., Vincter, M. G., Visser, J., Vogt, M., Volmer, J., Weiskopf, C., Wendland, J., Wilbert, J., Wise, T., Yen, S., Yoneyama, S., Bianchi, N., Zihlmann, B., Zohrabian, H., Zupranski, P., HERMES Collaboration, Blok, H. P., Bottcher, H., Akopov, Z., Borissov, A., Bouwhuis, M., Brack, J., Brull, A., Brunn, I., Capitani, G. P., Chiang, H. C., Ciullo, G., Contalbrigo, M., Court, G. R., Amarian, M., Dalpiaz, P. F., De Leo, R., De Nardo, L., De Sanctis, E., Devitsin, E., Di Nezza, P., Duren, M., Ehrenfried, M., Elalaoui-Moulay, A., Elbakian, G., Ammosov, V. V., Ellinghaus, F., Elschenbroich, U., Ely, J., Fabbri, R., Fantoni, A., Fechtchenko, A., Felawka, L., Fox, B., Franz, J., Frullani, S., Andrus, A., Garber, Y., Gapienko, G., Gapienko, V., Garibaldi, F., Garutti, E., Gaskell, D., Gavrilov, G., Gharibyan, V., Graw, G., Grebeniouk, O., Aschenauer, E. C., Greeniaus, L. G., Haeberli, W., Hafidi, K., Hartig, M., Hasch, D., Heesbeen, D., Henoch, M., Hertenberger, R., Hesselink, W. H. A., Hillenbrand, A., Augustyniak, W., Holler, Y., Hommez, B., Iarygin, G., Izotov, A., Jackson, H. E., Jgoun, A., Kaiser, R., Kinney, E., Kisselev, A., Konigsmann, K., Avakian, R., Kolster, H., Kopytin, M., Korotkov, V., Kozlov, V., Krauss, B., Krivokhijine, V. G., Lagamba, L., Lapikas, L., Laziev, A., Lenisa, P., Avetissian, A., Liebing, P., Lindemann, T., Lipka, K., Lorenzon, W., Makins, N. C. R., Marukyan, H., Masoli, F., Menden, F., Mexner, V., and Meyners, N.

Subjects
+Lambda+positron+anything%22">positron nucleon --> Lambda positron anything, longitudinal [polarized target], transverse [polarization], momentum dependence, HERMES, transverse momentum dependence, deep inelastic scattering [positron nucleon], polarized target: longitudinal, polarization: transverse, ddc:530, Nuclear Experiment, Antilambda: polarization, longitudinal [polarized beam], photoproduction [Lambda], 27.6 GeV, High Energy Physics::Phenomenology, Lambda: polarization, Lambda: photoproduction, DESY HERA Stor, positron nucleon: deep inelastic scattering, polarized beam: longitudinal, High Energy Physics::Experiment, polarization [Antilambda], polarization [Lambda], experimental results
Abstract

Physical review / D 76(9), 092008 (2007). doi:10.1103/PhysRevD.76.092008, The HERMES experiment has measured the transverse polarization of Lambda and Lambda-bar hyperons produced inclusively in quasireal photoproduction at a positron beam energy of 27.6 GeV. The transverse polarization of the Lambda hyperon is found to be positive while the observed Lambda-bar polarization is compatible with zero. The transverse polarization values averaged over the kinematic acceptance of HERMES are 0.078 +/- 0.006(stat) +/- 0.012(syst) and -0.025 +/- 0.015(stat) +/- 0.018(syst) for Lambda and Lambda-bar hyperons, respectively. The dependences of Lambda and Lambda-bar polarizations on the fraction $\zeta$ of the beam's light-cone momentum carried by the hyperon and on the hyperon's transverse momentum $p_T$ were investigated. The measured Lambda polarization rises linearly with $p_T$ and exhibits a different behavior for low and high values of $\zeta$, which approximately correspond to the backward and forward regions in the center-of-mass frame of the $\gamma^*N$ reaction., Published by Soc., [S.l.]

Published
2007
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8. Search for an exotic S = -2, Q = -2 baryon resonance at a mass near 1862-MeV in quasi-real photoproduction

Author

Airapetian, A., Akopov, N., Bailey, P., Meyners, N., Michler, T., Mikloukho, O., Miller, C. A., Miyachi, Y., Muccifora, V., Murray, M., Nagaitsev, A., Nappi, E., Naryshkin, Y., Balin, D., Negodaev, M., Nowak, W.-D., Oganessyan, K., Ohsuga, H., Osborne, A., Pickert, N., Potterveld, D. H., Raithel, M., Reggiani, D., Reimer, P. E., Beckmann, M., Reischl, A., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubacek, L., Rubin, J., Ryckbosch, D., Salomatin, Y., Belostotski, S., Sanjiev, I., Savin, I., Schafer, A., Schnell, G., Schuler, K. P., Seele, J., Seidl, R., Seitz, B., Shearer, C., Shibata, T.-A., Bianchi, N., Shutov, V., Sinram, K., Sommer, W., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stinzing, F., Blok, H. P., Tait, P., Tanaka, H., Taroian, S., Tchuiko, B., Terkulov, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., van der Nat, P. B., van der Steenhoven, G., Bottcher, H., van Haarlem, Y., Vikhrov, V., Vincter, M. G., Vogel, C., Volmer, J., Wang, S., Wendland, J., Ye, Y., Ye, Z., Yen, S., Borissov, A., Zihlmann, B., Zupranski, P., HERMES Collaboration, Borysenko, A., Bouwhuis, M., Akopov, Z., Brull, A., Bryzgalov, V., Capiluppi, M., Capitani, G. P., Chen, T., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., Amarian, M., Demey, M., De Nardo, L., De Sanctis, E., Devitsin, E., Diefenthaler, M., Di Nezza, P., Drechsler, J., Duren, M., Ehrenfried, M., Elalaoui-Moulay, A., Andrus, A., Elbakian, G., Ellinghaus, F., Elschenbroich, U., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Funel, A., Gapienko, G., Gapienko, V., Aschenauer, E. C., Garibaldi, F., Garrow, K., Gavrilov, G., Gharibyan, V., Giordano, F., Grebeniouk, O., Gregor, I. M., Hadjidakis, C., Hafidi, K., Hartig, M., Augustyniak, W., Hasch, D., Hesselink, W. H. A., Hillenbrand, A., Hoek, M., Holler, Y., Hommez, B., Hristova, I., Iarygin, G., Ivanilov, A., Izotov, A., Avakian, R., Jackson, H. E., Jgoun, A., Kaiser, R., Keri, T., Kinney, E., Kisselev, A., Kobayashi, T., Kopytin, M., Korotkov, V., Kozlov, V., Avetissian, A., Krauss, B., Krivokhijine, V. G., Lagamba, L., Lapikas, L., Laziev, A., Lenisa, P., Liebing, P., Linden-Levy, L. A., Lorenzon, W., Lu, H., Avetissian, E., Lu, J., Lu, S., Ma, B.-Q., Maiheu, B., Makins, N. C. R., Mao, Y., Marianski, B., Marukyan, H., Masoli, F., and Mexner, V.

Subjects
inclusive reaction [positron deuteron], (p 3pi-) [mass spectrum], branching ratio [channel cross section], DESY HERA Stor, 27.5 GeV, search for [pentaquark], ddc:530, exotic [baryon resonance], hadroproduction [Xi(1530)], (p pi+ 2pi-) [mass spectrum], Xi(1862) [postulated particle], upper limit
Abstract

A search for an exotic baryon resonance with $S=-2, Q=-2$ has been performed in quasi-real photoproduction on a deuterium target through the decay channel $\Xi^- \pi^- \to \Lambda \pi^- \pi^- \to p \pi^- \pi^- \pi^-$. No evidence for a previously reported $\Xi^{--}(1860)$ resonance is found in the $\Xi^- \pi^-$invariant mass spectrum. An upper limit for the photoproduction cross section of 2.1 nb is found at the 90% confidence level. The photoproduction cross section for the $\Xi^{0}(1530)$ is found to be between 9 and 24 nb.

Published
2005
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9. First measurement of the tensor structure function $b_1$ of the deuteron

Author

Airapetian, A., Akopov, N., Avetissian, E., Makins, N. C. R., Mao, Y., Marianski, B., Marukyan, H., Masoli, F., Mexner, V., Meyners, N., Mikloukho, O., Miller, C. A., Miyachi, Y., Bailey, P., Muccifora, V., Nagaitsev, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W.-D., Oganessyan, K., Ohsuga, H., Pickert, N., Balin, D., Potashov, S., Potterveld, D. H., Raithel, M., Reggiani, D., Reimer, P. E., Reischl, A., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Baturin, V., Rostomyan, A., Rubacek, L., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanjiev, I., Savin, I., Schafer, A., Schill, C., Schnell, G., Beckmann, M., Schuler, K. P., Seele, J., Seidl, R., Seitz, B., Shanidze, R., Shearer, C., Shibata, T.-A., Shutov, V., Simani, M. C., Sinram, K., Belostotski, S., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stinzing, F., Stosslein, U., Tait, P., Tanaka, H., Bernreuther, S., Taroian, S., Tchuiko, B., Terkulov, A., Tkabladze, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., van der Nat, P. B., van der Steenhoven, G., Vetterli, M. C., Bianchi, N., Vikhrov, V., Vincter, M. G., Vogel, C., Vogt, M., Volmer, J., Weiskopf, C., Wendland, J., Wilbert, J., Ye, Y., Ye, Z., Blok, H. P., Yen, S., Zihlmann, B., Zupranski, P., HERMES Collaboration, Bottcher, H., Akopov, Z., Borissov, A., Borysenko, A., Bouwhuis, M., Brack, J., Brull, A., Bryzgalov, V., Capitani, G. P., Chen, T., Chiang, H. C., Ciullo, G., Amarian, M., Contalbrigo, M., Dalpiaz, P. F., Leo, R. De, Demey, M., Nardo, L. De, Sanctis, E. De, Devitsin, E., Nezza, P. Di, Dreschler, J., Duren, M., Ammosov, V. V., Ehrenfried, M., Elalaoui-Moulay, A., Elbakian, G., Ellinghaus, F., Elschenbroich, U., Fabbri, R., Fantoni, A., Fechtchenko, A., Felawka, L., Fox, B., Andrus, A., Frullani, S., Gapienko, G., Gapienko, V., Garibaldi, F., Garrow, K., Garutti, E., Gaskell, D., Gavrilov, G., Gharibyan, V., Graw, G., Aschenauer, E. C., Grebeniouk, O., Greeniaus, L. G., Gregor, I. M., Hafidi, K., Hartig, M., Hasch, D., Heesbeen, D., Henoch, M., Hertenberger, R., Hesselink, W. H. A., Augustyniak, W., Hillenbrand, A., Hoek, M., Holler, Y., Hommez, B., Iarygin, G., Ivanilov, A., Izotov, A., Jackson, H. E., Jgoun, A., Kaiser, R., Avakian, R., Kinney, E., Kisselev, A., Kopytin, M., Korotkov, V., Kozlov, V., Krauss, B., Krivokhijine, V. G., Lagamba, L., Lapikas, L., Laziev, A., Avetissian, A., Lenisa, P., Liebing, P., Linden-Levy, L. A., Lipka, K., Lorenzon, W., Lu, H., Lu, J., Lu, S., Ma, B.-Q., and Maiheu, B.

Subjects
DESY HERA Stor, 27.6 GeV/c, structure function [deuteron], deep inelastic scattering [positron deuteron], asymmetry [polarization], ddc:550, tensor [polarization], HERMES, moment [structure function], polarized target [deuteron], momentum transfer dependence, x-dependence, experimental results
Published
2005
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10. First measurement of the tensor structure function $b_1$ of the deuteron

Author

Airapetian, A., Akopov, N., Akopov, Z., Amarian, M., Ammosov, V. V., Andrus, A., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetissian, E., Bailey, P., Balin, D., Baturin, V., Beckmann, M., Belostotski, S., Bernreuther, S., Bianchi, N., Blok, H. P., Bottcher, H., Borissov, A., Borysenko, A., Bouwhuis, M., Brack, J., Brull, A., Bryzgalov, V., Capitani, G. P., Chen, T., Chiang, H. C., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Leo, R. De, Demey, M., Nardo, L. De, Sanctis, E. De, Devitsin, E., Nezza, P. Di, Dreschler, J., Duren, M., Ehrenfried, M., Elalaoui-Moulay, A., Elbakian, G., Ellinghaus, F., Elschenbroich, U., Fabbri, R., Fantoni, A., Fechtchenko, A., Felawka, L., Fox, B., Frullani, S., Gapienko, G., Gapienko, V., Garibaldi, F., Garrow, K., Garutti, E., Gaskell, D., Gavrilov, G., Gharibyan, V., Graw, G., Grebeniouk, O., Greeniaus, L. G., Gregor, I. M., Hafidi, K., Hartig, M., Hasch, D., Heesbeen, D., Henoch, M., Hertenberger, R., Hesselink, W. H. A., Hillenbrand, A., Hoek, M., Holler, Y., Hommez, B., Iarygin, G., Ivanilov, A., Izotov, A., Jackson, H. E., Jgoun, A., Kaiser, R., Kinney, E., Kisselev, A., Kopytin, M., Korotkov, V., Kozlov, V., Krauss, B., Krivokhijine, V. G., Lagamba, L., Lapikas, L., Laziev, A., Lenisa, P., Liebing, P., Linden-Levy, L. A., Lipka, K., Lorenzon, W., Lu, H., Lu, J., Lu, S., Ma, B.-Q., Maiheu, B., Makins, N. C. R., Mao, Y., Marianski, B., Marukyan, H., Masoli, F., Mexner, V., Meyners, N., Mikloukho, O., Miller, C. A., Miyachi, Y., Muccifora, V., Nagaitsev, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W.-D., Oganessyan, K., Ohsuga, H., Pickert, N., Potashov, S., Potterveld, D. H., Raithel, M., Reggiani, D., Reimer, P. E., Reischl, A., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubacek, L., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanjiev, I., Savin, I., Schafer, A., Schill, C., Schnell, G., Schuler, K. P., Seele, J., Seidl, R., Seitz, B., Shanidze, R., Shearer, C., Shibata, T.-A., Shutov, V., Simani, M. C., Sinram, K., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stinzing, F., Stosslein, U., Tait, P., Tanaka, H., Taroian, S., Tchuiko, B., Terkulov, A., Tkabladze, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., Van Der Nat, P. B., Van Der Steenhoven, G., Vetterli, M. C., Vikhrov, V., Vincter, M. G., Vogel, C., Vogt, M., Volmer, J., Weiskopf, C., Wendland, J., Wilbert, J., Ye, Y., Ye, Z., Yen, S., Zihlmann, B., and Zupranski, P.

Subjects
deuteron: polarized target, DESY HERA Stor, positron deuteron: deep inelastic scattering, polarization: asymmetry, 27.6 GeV/c, polarization: tensor, deuteron: structure function, HERMES, structure function: moment, momentum transfer dependence, x-dependence, experimental results
Abstract

Physical review letters 95(24), 242001 (2005). doi:10.1103/PhysRevLett.95.242001, Published by APS, College Park, Md.

Published
2005
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11. Quark helicity distributions in the nucleon for up, down, and strange quarks from semi-inclusive deep-inelastic scattering

Author

Airapetian, A., Akopov, N., Avetissian, E., Marianski, B., Marukyan, H., Masoli, F., Mexner, V., Meyners, N., Mikloukho, O., Miller, C. A., Miyachi, Y., Muccifora, V., Nagaitsev, A., Bailey, P., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. D., Oganessyan, K., Ohsuga, H., Pickert, N., Potashov, S., Potterveld, D. H., Baturin, V., Raithel, M., Reggiani, D., Reimer, P. E., Reischl, A., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubacek, L., Baumgarten, C., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanjiev, I., Savin, I., Scarlett, C., Schafer, A., Schill, C., Schnell, G., Schuler, K. P., Beckmann, M., Schwind, A., Seele, J., Seidl, R., Seitz, B., Shanidze, R., Shearer, C., Shibata, T. A., Shutov, V., Simani, M. C., Sinram, K., Belostotski, S., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stosslein, U., Tait, P., Tanaka, H., Taroian, S., Bernreuther, S., Tchuiko, B., Terkulov, A., Tkabladze, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., van der Nat, P., van der Steenhoven, G., Vetterli, M. C., Vikhrov, V., Bianchi, N., Vincter, M. G., Vogel, C., Vogt, M., Volmer, J., Weiskopf, C., Wendland, J., Wilbert, J., Ybeles Smit, G., Yen, S., Zihlmann, B., Blok, H. P., Zohrabian, H., Zupranski, P., HERMES Collaboration, Blumlein, J., Akopov, Z., Bottcher, H., Borissov, A., Borysenko, A., Bouwhuis, M., Brack, J., Brull, A., Bryzgalov, V., Capitani, G. P., Chiang, H. C., Ciullo, G., Amarian, M., Contalbrigo, M., Dalpiaz, P. F., De Leo, R., De Nardo, L., De Sanctis, E., Devitsin, E., Di Nezza, P., Duren, M., Ehrenfried, M., Elalaoui-Moulay, A., Ammosov, V. V., Elbakian, G., Ellinghaus, F., Elschenbroich, U., Ely, J., Fabbri, R., Fantoni, A., Fechtchenko, A., Felawka, L., Fox, B., Franz, J., Andrus, A., Frullani, S., Gapienko, G., Gapienko, V., Garibaldi, F., Garrow, K., Garutti, E., Gaskell, D., Gavrilov, G., Gharibyan, V., Graw, G., Aschenauer, E. C., Grebeniouk, O., Greeniaus, L. G., Gregor, I. M., Hafidi, K., Hartig, M., Hasch, D., Heesbeen, D., Henoch, M., Hertenberger, R., Hesselink, W. H. A., Augustyniak, W., Hillenbrand, A., Hoek, M., Holler, Y., Hommez, B., Iarygin, G., Ivanilov, A., Izotov, A., Jackson, H. E., Jgoun, A., Kaiser, R., Avakian, R., Kinney, E., Kisselev, A., Konigsmann, K., Kopytin, M., Korotkov, V., Kozlov, V., Krauss, B., Krivokhijine, V. G., Lagamba, L., Lapikas, Louk, Avetissian, A., Laziev, A., Lenisa, P., Liebing, P., Lindemann, T., Linden-Levy, L. A., Lipka, K., Lorenzon, W., Lu, J., Maiheu, B., Makins, N. C. R., (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education

Subjects
Quark, internal [polarized target], Nuclear and High Energy Physics, Particle physics, Strange quark, sea [quark], High Energy Physics::Lattice, deep inelastic scattering [positron deuteron], Hadron, Nuclear Theory, dependence [flavor], Down quark, FOS: Physical sciences, HERMES, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), density [helicity], 27.5 GeV, Pion, 0103 physical sciences, ddc:530, SDG 14 - Life Below Water, deep inelastic scattering [positron p], 010306 general physics, electroproduction [pi], Physics, 010308 nuclear & particles physics, High Energy Physics::Phenomenology, polarization [quark], Deep inelastic scattering, moment, Baryon, DESY HERA Stor, electroproduction [K], Up quark, valence [quark], polarization [cross section], High Energy Physics::Experiment, polarized beam [positron], asymmetry [spin], experimental results
Abstract

Polarized deep-inelastic scattering data on longitudinally polarized hydrogen and deuterium targets have been used to determine double-spin asymmetries of cross sections. Inclusive and semi-inclusive asymmetries for the production of positive and negative pions from hydrogen were obtained in a reanalysis of previously published data. Inclusive and semi-inclusive asymmetries for the production of negative and positive pions and kaons were measured on a polarized deuterium target. The separate helicity densities for the up and down quarks and the anti-up, anti-down, and strange sea quarks were computed from these asymmetries in a "leading order" QCD analysis. The polarization of the up-quark is positive and that of the down-quark is negative. All extracted sea quark polarizations are consistent with zero, and the light quark sea helicity densities are flavor symmetric within the experimental uncertainties. First and second moments of the extracted quark helicity densities in the measured range are consistent with fits of inclusive data. © 2005 The American Physical Society.

Published
2005
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12. Single-spin asymmetries in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target

Author

Airapetian, A., Akopov, N., Bacchetta, A., Mikloukho, O., Miller, C. A., Miyachi, Y., Muccifora, V., Nagaitsev, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. D., Bailey, P., Oganessyan, K., Ohsuga, H., Osborne, A., Pickert, N., Potterveld, D. H., Raithel, M., Reggiani, D., Reimer, P. E., Reischl, A., Reolon, A. R., Balin, D., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubacek, L., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanjiev, I., Savin, Igor A., Beckmann, M., Schafer, A., Schill, C., Schnell, G., Schuler, K. P., Seele, J., Seidl, R., Seitz, B., Shanidze, R., Shearer, C., Shibata, T. A., Belostotski, S., Shutov, V., Sinram, K., Sommer, W., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stinzing, F., Bianchi, N., Tait, P., Tanaka, H., Taroian, S., Tchuiko, B., Terkulov, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., van der Nat, P. B., van der Steenhoven, G., Blok, H. P., van Haarlem, Y., Vetterli, M. C., Vikhrov, V., Vincter, M. G., Vogel, C., Volmer, J., Wang, S., Wendland, J., Wilbert, J., Ybeles Smit, G., Bottcher, H., Ye, Y., Ye, Z., Yen, S., Zihlmann, B., Zupranski, P., HERMES Collaboration, Borissov, A., Borysenko, A., Akopov, Z., Bouwhuis, M., Brull, A., Bryzgalov, V., Capitani, G. P., Cappiluppi, M., Chen, T., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., De Leo, R., Amarian, M., Demey, M., De Nardo, L., De Sanctis, E., Devitsin, E., Di Nezza, P., Duren, M., Ehrenfried, M., Elalaoui-Moulay, A., Elbakian, G., Ellinghaus, F., Andrus, A., Elschenbroich, U., Fabbri, R., Fantoni, A., Fechtchenko, A., Felawka, L., Frullani, S., Gapienko, G., Gapienko, V., Garibaldi, F., Garrow, K., Aschenauer, E. C., Gavrilov, G., Gharibyan, V., Grebeniouk, O., Gregor, I. M., Hadjidakis, C., Hafidi, K., Hartig, M., Hasch, D., Henoch, M., Hesselink, W. H. A., Augustyniak, W., Hillenbrand, A., Hoek, M., Holler, Y., Hommez, B., Hristova, I., Iarygin, G., Ilyichev, A., Ivanilov, A., Izotov, A., Jackson, H. E., Avakian, R., Jgoun, A., Kaiser, R., Kinney, E., Kisselev, A., Kobayashi, T., Kopytin, M., Korotkov, V., Kozlov, V., Krauss, B., Krivokhijine, V. G., Avetissian, A., Lagamba, L., Lapikas, Louk, Laziev, A., Lenisa, P., Liebing, P., Linden-Levy, L. A., Lorenzon, W., Lu, H., Lu, J., Lu, S., Avetissian, E., Ma, B. Q., Maiheu, B., Makins, N. C. R., Mao, Y., Marianski, B., Marukyan, H., Masoli, F., Mexner, V., Meyners, N., Michler, T., (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education

Subjects
Particle physics, transverse [polarization], Nuclear Theory, FOS: Physical sciences, General Physics and Astronomy, HERMES, 13.60.–r, Inelastic scattering, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), 27.5 GeV, Pion, 13.88.+e, ddc:550, Vector meson, SDG 14 - Life Below Water, deep inelastic scattering [positron p], 14.20.Dh, 14.65.–q, Nuclear Experiment, Physics, Scattering, polarized target [hydrogen], High Energy Physics::Phenomenology, polarization [quark], Deep inelastic scattering, +pi+positron+anything%22">positron p --> pi positron anything, angular dependence, DESY HERA Stor, Distribution function, High Energy Physics::Experiment, transverse momentum [quark], Nucleon, electroproduction [pi+], asymmetry [spin], electroproduction [pi-], Lepton, experimental results
Abstract

Single-spin asymmetries for semi-inclusive electroproduction of charged pions in deep-inelastic scattering of positrons are measured for the first time with transverse target polarization. The asymmetry depends on the azimuthal angles of both the pion ($\ensuremath{\phi}$) and the target spin axis (${\ensuremath{\phi}}_{S}$) about the virtual-photon direction and relative to the lepton scattering plane. The extracted Fourier component $\mathbf{⟨}\mathrm{sin} (\ensuremath{\phi}+{\ensuremath{\phi}}_{S}){\mathbf{⟩}}_{UT}^{\ensuremath{\pi}}$ is a signal of the previously unmeasured quark transversity distribution, in conjunction with the Collins fragmentation function, also unknown. The component $\mathbf{⟨}\mathrm{sin} (\ensuremath{\phi}\ensuremath{-}{\ensuremath{\phi}}_{S}{\mathbf{⟩}}_{UT}^{\ensuremath{\pi}}$ arises from a correlation between the transverse polarization of the target nucleon and the intrinsic transverse momentum of quarks, as represented by the previously unmeasured Sivers distribution function. Evidence for both signals is observed, but the Sivers asymmetry may be affected by exclusive vector meson production.

Published
2005
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13. Search for an exotic S = -2, Q = -2 baryon resonance at a mass near 1862-MeV in quasi-real photoproduction

Author

Airapetian, A., Akopov, N., Akopov, Z., Amarian, M., Andrus, A., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetissian, E., Bailey, P., Balin, D., Beckmann, M., Belostotski, S., Bianchi, N., Blok, H. P., Bottcher, H., Borissov, A., Borysenko, A., Bouwhuis, M., Brull, A., Bryzgalov, V., Capiluppi, M., Capitani, G. P., Chen, T., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., Demey, M., De Nardo, L., De Sanctis, E., Devitsin, E., Diefenthaler, M., Di Nezza, P., Drechsler, J., Duren, M., Ehrenfried, M., Elalaoui-Moulay, A., Elbakian, G., Ellinghaus, F., Elschenbroich, U., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Funel, A., Gapienko, G., Gapienko, V., Garibaldi, F., Garrow, K., Gavrilov, G., Gharibyan, V., Giordano, F., Grebeniouk, O., Gregor, I. M., Hadjidakis, C., Hafidi, K., Hartig, M., Hasch, D., Hesselink, W. H. A., Hillenbrand, A., Hoek, M., Holler, Y., Hommez, B., Hristova, I., Iarygin, G., 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., Krauss, B., Krivokhijine, V. G., Lagamba, L., Lapikas, L., Laziev, A., Lenisa, P., Liebing, P., Linden-Levy, L. A., Lorenzon, W., Lu, H., Lu, J., Lu, S., Ma, B.-Q., Maiheu, B., Makins, N. C. R., Mao, Y., Marianski, B., Marukyan, H., Masoli, F., Mexner, V., Meyners, N., Michler, T., Mikloukho, O., Miller, C. A., Miyachi, Y., Muccifora, V., Murray, M., Nagaitsev, A., Nappi, E., Naryshkin, Y., Negodaev, M., Nowak, W.-D., Oganessyan, K., Ohsuga, H., Osborne, A., Pickert, N., Potterveld, D. H., Raithel, M., Reggiani, D., Reimer, P. E., Reischl, A., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubacek, L., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanjiev, I., Savin, I., Schafer, A., Schnell, G., Schuler, K. P., Seele, J., Seidl, R., Seitz, B., Shearer, C., Shibata, T.-A., Shutov, V., Sinram, K., Sommer, W., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stinzing, F., Tait, P., Tanaka, H., Taroian, S., Tchuiko, B., Terkulov, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., Van Der Nat, P. B., Van Der Steenhoven, G., Van Haarlem, Y., Vikhrov, V., Vincter, M. G., Vogel, C., Volmer, J., Wang, S., Wendland, J., Ye, Y., Ye, Z., Yen, S., Zihlmann, B., and Zupranski, P.

Subjects
DESY HERA Stor, 27.5 GeV, positron deuteron: inclusive reaction, baryon resonance: exotic, mass spectrum: (p pi+ 2pi-), channel cross section: branching ratio, Xi(1530): hadroproduction, postulated particle: Xi(1862), pentaquark: search for, mass spectrum: (p 3pi-), upper limit
Abstract

Physical review / D 71(3), 032004 (2005). doi:10.1103/PhysRevD.71.032004, A search for an exotic baryon resonance with $S=-2, Q=-2$ has been performed in quasi-real photoproduction on a deuterium target through the decay channel $\Xi^- \pi^- \to \Lambda \pi^- \pi^- \to p \pi^- \pi^- \pi^-$. No evidence for a previously reported $\Xi^{--}(1860)$ resonance is found in the $\Xi^- \pi^-$invariant mass spectrum. An upper limit for the photoproduction cross section of 2.1 nb is found at the 90% confidence level. The photoproduction cross section for the $\Xi^{0}(1530)$ is found to be between 9 and 24 nb., Published by Inst., Woodbury, NY

Published
2005
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14. Single-spin asymmetries in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target

Author

Airapetian, A., Akopov, N., Akopov, Z., Amarian, M., Andrus, A., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetissian, E., Bacchetta, A., Bailey, P., Balin, D., Beckmann, M., Belostotski, S., Bianchi, N., Blok, H. P., Bottcher, H., Borissov, A., Borysenko, A., Bouwhuis, M., Brull, A., Bryzgalov, V., Capitani, G. P., Cappiluppi, M., Chen, T., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., De Leo, R., Demey, M., De Nardo, L., De Sanctis, E., Devitsin, E., Di Nezza, P., Duren, M., Ehrenfried, M., Elalaoui-Moulay, A., Elbakian, G., Ellinghaus, F., Elschenbroich, U., Fabbri, R., Fantoni, A., Fechtchenko, A., Felawka, L., Frullani, S., Gapienko, G., Gapienko, V., Garibaldi, F., Garrow, K., Gavrilov, G., Gharibyan, V., Grebeniouk, O., Gregor, I. M., Hadjidakis, C., Hafidi, K., Hartig, M., Hasch, D., Henoch, M., Hesselink, W. H. A., Hillenbrand, A., Hoek, M., Holler, Y., Hommez, B., Hristova, I., Iarygin, G., Ilyichev, A., Ivanilov, A., Izotov, A., Jackson, H. E., Jgoun, A., Kaiser, R., Kinney, E., Kisselev, A., Kobayashi, T., Kopytin, M., Korotkov, V., Kozlov, V., Krauss, B., Krivokhijine, V. G., Lagamba, L., Lapikas, Louk, Laziev, A., Lenisa, P., Liebing, P., Linden-Levy, L. A., Lorenzon, W., Lu, H., Lu, J., Lu, S., Ma, B. Q., Maiheu, B., Makins, N. C. R., Mao, Y., Marianski, B., Marukyan, H., Masoli, F., Mexner, V., Meyners, N., Michler, T., Mikloukho, O., Miller, C. A., Miyachi, Y., Muccifora, V., Nagaitsev, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. D., Oganessyan, K., Ohsuga, H., Osborne, A., Pickert, N., Potterveld, D. H., Raithel, M., Reggiani, D., Reimer, P. E., Reischl, A., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubacek, L., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanjiev, I., Savin, Igor A., Schafer, A., Schill, C., Schnell, G., Schuler, K. P., Seele, J., Seidl, R., Seitz, B., Shanidze, R., Shearer, C., Shibata, T. A., Shutov, V., Sinram, K., Sommer, W., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stinzing, F., Tait, P., Tanaka, H., Taroian, S., Tchuiko, B., Terkulov, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., Van Der Nat, P. B., Van Der Steenhoven, G., Van Haarlem, Y., Vetterli, M. C., Vikhrov, V., Vincter, M. G., Vogel, C., Volmer, J., Wang, S., Wendland, J., Wilbert, J., Ybeles Smit, G., Ye, Y., Ye, Z., Yen, S., Zihlmann, B., and Zupranski, P.

Subjects
positron p: deep inelastic scattering, pi+: electroproduction, HERMES, angular dependence, DESY HERA Stor, +pi+positron+anything%22">positron p --> pi positron anything, 27.5 GeV, hydrogen: polarized target, pi-: electroproduction, polarization: transverse, quark: transverse momentum, quark: polarization, spin: asymmetry, experimental results
Abstract

Physical review letters 94(1), 012002 (2005). doi:10.1103/PhysRevLett.94.012002, Single-spin asymmetries for semi-inclusive electroproduction of charged pions in deep-inelastic scattering of positrons are measured for the first time with transverse target polarization. The asymmetry depends on the azimuthal angles of both the pion ($\phi$) and the target spin axis ($\phi_S$) about the virtual photon direction and relative to the lepton scattering plane. The extracted Fourier component $\pi$ is a signal of the previously unmeasured quark transversity distribution, in conjunction with the so-called Collins fragmentation function, also unknown. The Fourier component $\pi$ of the asymmetry arises from a correlation between the transverse polarization of the target nucleon and the intrinsic transverse momentum of quarks, as represented by the previously unmeasured Sivers distribution function. Evidence for both signals is observed, but the Sivers asymmetry may be affected by exclusive vector meson production, Published by APS, College Park, Md.

Published
2005
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15. Quark helicity distributions in the nucleon for up, down, and strange quarks from semi-inclusive deep-inelastic scattering

Author

Airapetian, A., Akopov, N., Akopov, Z., Amarian, M., Ammosov, V. V., Andrus, A., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetissian, E., Bailey, P., Baturin, V., Baumgarten, C., Beckmann, M., Belostotski, S., Bernreuther, S., Bianchi, N., Blok, H. P., Blumlein, J., Bottcher, H., Borissov, A., Borysenko, A., Bouwhuis, M., Brack, J., Brull, A., Bryzgalov, V., Capitani, G. P., Chiang, H. C., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., De Leo, R., De Nardo, L., De Sanctis, E., Devitsin, E., Di Nezza, P., Duren, M., Ehrenfried, M., Elalaoui-Moulay, A., Elbakian, G., Ellinghaus, F., Elschenbroich, U., Ely, J., Fabbri, R., Fantoni, A., Fechtchenko, A., Felawka, L., Fox, B., Franz, J., Frullani, S., Gapienko, G., Gapienko, V., Garibaldi, F., Garrow, K., Garutti, E., Gaskell, D., Gavrilov, G., Gharibyan, V., Graw, G., Grebeniouk, O., Greeniaus, L. G., Gregor, I. M., Hafidi, K., Hartig, M., Hasch, D., Heesbeen, D., Henoch, M., Hertenberger, R., Hesselink, W. H. A., Hillenbrand, A., Hoek, M., Holler, Y., Hommez, B., Iarygin, G., Ivanilov, A., Izotov, A., Jackson, H. E., Jgoun, A., Kaiser, R., Kinney, E., Kisselev, A., Konigsmann, K., Kopytin, M., Korotkov, V., Kozlov, V., Krauss, B., Krivokhijine, V. G., Lagamba, L., Lapikas, Louk, Laziev, A., Lenisa, P., Liebing, P., Lindemann, T., Linden-Levy, L. A., Lipka, K., Lorenzon, W., Lu, J., Maiheu, B., Makins, N. C. R., Marianski, B., Marukyan, H., Masoli, F., Mexner, V., Meyners, N., Mikloukho, O., Miller, C. A., Miyachi, Y., Muccifora, V., Nagaitsev, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. D., Oganessyan, K., Ohsuga, H., Pickert, N., Potashov, S., Potterveld, D. H., Raithel, M., Reggiani, D., Reimer, P. E., Reischl, A., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubacek, L., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanjiev, I., Savin, I., Scarlett, C., Schafer, A., Schill, C., Schnell, G., Schuler, K. P., Schwind, A., Seele, J., Seidl, R., Seitz, B., Shanidze, R., Shearer, C., Shibata, T. A., Shutov, V., Simani, M. C., Sinram, K., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stosslein, U., Tait, P., Tanaka, H., Taroian, S., Tchuiko, B., Terkulov, A., Tkabladze, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., Van Der Nat, P., Van Der Steenhoven, G., Vetterli, M. C., Vikhrov, V., Vincter, M. G., Vogel, C., Vogt, M., Volmer, J., Weiskopf, C., Wendland, J., Wilbert, J., Ybeles Smit, G., Yen, S., Zihlmann, B., Zohrabian, H., and Zupranski, P.

Subjects
positron: polarized beam, quark: sea, positron p: deep inelastic scattering, HERMES, cross section: polarization, helicity: density, moment, pi: electroproduction, flavor: dependence, DESY HERA Stor, 27.5 GeV, positron deuteron: deep inelastic scattering, quark: valence, polarized target: internal, K: electroproduction, quark: polarization, spin: asymmetry, experimental results
Abstract

Physical review / D 71(1), 012003 (2005). doi:10.1103/PhysRevD.71.012003, Polarized deep--inelastic scattering data on longitudinally polarized hydrogen and deuterium targets have been used to determine double spin asymmetries of cross sections. Inclusive and semi--inclusive asymmetries for the production of positive and negative pions from hydrogen were obtained in a re--analysis of previously published data. Inclusive and semi--inclusive asymmetries for the production of negative and positive pions and kaons were measured on a polarized deuterium target. The separate helicity densities for the up and down quarks and the anti--up, anti--down, and strange sea quarks were computed from these asymmetries in a ``leading order QCD analysis. The polarization of the up--quark is positive and that of the down--quark is negative. All extracted sea quark polarizations are consistent with zero, and the light quark sea helicity densities are flavor symmetric within the experimental uncertainties. First and second moments of the extracted quark helicity densities in the measured range are consistent with fits of inclusive data., Published by Inst., Woodbury, NY

Published
2005
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16. Flavor decomposition of the sea quark helicity distributions in the nucleon from semiinclusive deep inelastic scattering

Author

Airapetian, A., Akopov, N., Avetissian, E., Mexner, V., Meyners, N., Mikloukho, O., Miller, C. A., Miyachi, Y., Muccifora, V., Nagaitsev, A., Nappi, E., Naryshkin, Y., Nass, A., Bailey, P., Negodaev, M., Nowak, W.-D., Oganessyan, K., Ohsuga, H., Orlandi, G., Pickert, N., Potashov, S., Potterveld, D. H., Raithel, M., Reggiani, D., Baturin, V., Reimer, P. E., Reischl, A., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubacek, L., Ryckbosch, D., Salomatin, Y., Baumgarten, C., Sanjiev, I., Savin, I., Scarlett, C., Schafer, A., Schill, C., Schnell, G., Schuler, K. P., Schwind, A., Seele, J., Seidl, R., Beckmann, M., Seitz, B., Shanidze, R., Shearer, C., Shibata, T.-A., Shutov, V., Simani, M. C., Sinram, K., Stancari, M., Statera, M., Steffens, E., Belostotski, S., Steijger, J. J. M., Stewart, J., Stosslein, U., Tait, P., Tanaka, H., Taroian, S., Tchuiko, B., Terkulov, A., Tkabladze, A., Trzcinski, A., Bernreuther, S., Tytgat, M., Vandenbroucke, A., van der Nat, P., van der Steenhoven, G., Vetterli, M. C., Vikhrov, V., Vincter, M. G., Visser, J., Vogel, C., Vogt, M., Bianchi, N., Volmer, J., Weiskopf, C., Wendland, J., Wilbert, J., Ybeles Smit, G., Yen, S., Zihlmann, B., Zohrabian, H., Zupranski, P., HERMES Collaboration, Blok, H. P., Bottcher, H., Akopov, Z., Borissov, A., Bouwhuis, M., Brack, J., Brull, A., Bryzgalov, V., Capitani, G. P., Chiang, H. C., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Amarian, M., De Leo, R., De Nardo, L., De Sanctis, E., Devitsin, E., Di Nezza, P., Duren, M., Ehrenfried, M., Elalaoui-Moulay, A., Elbakian, G., Ellinghaus, F., Ammosov, V. V., Elschenbroich, U., Ely, J., Fabbri, R., Fantoni, A., Fechtchenko, A., Felawka, L., Fox, B., Franz, J., Frullani, S., Garber, Y., Andrus, A., Gapienko, G., Gapienko, V., Garibaldi, F., Garrow, K., Garutti, E., Gaskell, D., Gavrilov, G., Gharibyan, V., Graw, G., Grebeniouk, O., Aschenauer, E. C., Greeniaus, L. G., Hafidi, K., Hartig, M., Hasch, D., Heesbeen, D., Henoch, M., Hertenberger, R., Hesselink, W. H. A., Hillenbrand, A., Hoek, M., Augustyniak, W., Holler, Y., Hommez, B., Iarygin, G., Ivanilov, A., Izotov, A., Jackson, H. E., Jgoun, A., Kaiser, R., Kinney, E., Kisselev, A., Avakian, R., Konigsmann, K., Kopytin, M., Korotkov, V., Kozlov, V., Krauss, B., Krivokhijine, V. G., Lagamba, L., Lapikas, L., Laziev, A., Lenisa, P., Avetissian, A., Liebing, P., Lindemann, T., Lipka, K., Lorenzon, W., Lu, J., Maiheu, B., Makins, N. C. R., Marianski, B., Marukyan, H., and Masoli, F.

Subjects
sea [quark], momentum spectrum [quark], High Energy Physics::Lattice, deep inelastic scattering [positron deuteron], Nuclear Theory, HERMES, absorption [photon], x-dependence, inclusive reaction [positron deuteron], helicity [quark], ddc:550, Nuclear Experiment, 27.6 GeV, High Energy Physics::Phenomenology, DESY HERA Stor, electroproduction [K+], electroproduction [K-], flavor [quark], High Energy Physics::Experiment, asymmetry [flavor], polarized beam [positron], polarized target [deuteron], electroproduction [pi+], asymmetry [spin], electroproduction [pi-], experimental results
Abstract

Double-spin asymmetries of semi-inclusive cross sections for the production of identified pions and kaons have been measured in deep-inelastic scattering of polarized positrons on a polarized deuterium target. Five helicity distributions including those for three sea quark flavors were extracted from these data together with re-analyzed previous data for identified pions from a hydrogen target. These distributions are consistent with zero for all three sea flavors. A recently predicted flavor asymmetry in the polarization of the light quark sea appears to be disfavored by the data.

Published
2004
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17. Flavor decomposition of the sea quark helicity distributions in the nucleon from semiinclusive deep inelastic scattering

Author

Airapetian, A., Akopov, N., Akopov, Z., Amarian, M., Ammosov, V. V., Andrus, A., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetissian, E., Bailey, P., Baturin, V., Baumgarten, C., Beckmann, M., Belostotski, S., Bernreuther, S., Bianchi, N., Blok, H. P., Bottcher, H., Borissov, A., Bouwhuis, M., Brack, J., Brull, A., Bryzgalov, V., Capitani, G. P., Chiang, H. C., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., De Leo, R., De Nardo, L., De Sanctis, E., Devitsin, E., Di Nezza, P., Duren, M., Ehrenfried, M., Elalaoui-Moulay, A., Elbakian, G., Ellinghaus, F., Elschenbroich, U., Ely, J., Fabbri, R., Fantoni, A., Fechtchenko, A., Felawka, L., Fox, B., Franz, J., Frullani, S., Garber, Y., Gapienko, G., Gapienko, V., Garibaldi, F., Garrow, K., Garutti, E., Gaskell, D., Gavrilov, G., Gharibyan, V., Graw, G., Grebeniouk, O., Greeniaus, L. G., Hafidi, K., Hartig, M., Hasch, D., Heesbeen, D., Henoch, M., Hertenberger, R., Hesselink, W. H. A., Hillenbrand, A., Hoek, M., Holler, Y., Hommez, B., Iarygin, G., Ivanilov, A., Izotov, A., Jackson, H. E., Jgoun, A., Kaiser, R., Kinney, E., Kisselev, A., Konigsmann, K., Kopytin, M., Korotkov, V., Kozlov, V., Krauss, B., Krivokhijine, V. G., Lagamba, L., Lapikas, L., Laziev, A., Lenisa, P., Liebing, P., Lindemann, T., Lipka, K., Lorenzon, W., Lu, J., Maiheu, B., Makins, N. C. R., Marianski, B., Marukyan, H., Masoli, F., Mexner, V., Meyners, N., Mikloukho, O., Miller, C. A., Miyachi, Y., Muccifora, V., Nagaitsev, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W.-D., Oganessyan, K., Ohsuga, H., Orlandi, G., Pickert, N., Potashov, S., Potterveld, D. H., Raithel, M., Reggiani, D., Reimer, P. E., Reischl, A., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubacek, L., Ryckbosch, D., Salomatin, Y., Sanjiev, I., Savin, I., Scarlett, C., Schafer, A., Schill, C., Schnell, G., Schuler, K. P., Schwind, A., Seele, J., Seidl, R., Seitz, B., Shanidze, R., Shearer, C., Shibata, T.-A., Shutov, V., Simani, M. C., Sinram, K., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stewart, J., Stosslein, U., Tait, P., Tanaka, H., Taroian, S., Tchuiko, B., Terkulov, A., Tkabladze, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., Van Der Nat, P., Van Der Steenhoven, G., Vetterli, M. C., Vikhrov, V., Vincter, M. G., Visser, J., Vogel, C., Vogt, M., Volmer, J., Weiskopf, C., Wendland, J., Wilbert, J., Ybeles Smit, G., Yen, S., Zihlmann, B., Zohrabian, H., and Zupranski, P.

Subjects
positron: polarized beam, deuteron: polarized target, quark: sea, quark: flavor, 27.6 GeV, pi+: electroproduction, photon: absorption, HERMES, quark: momentum spectrum, x-dependence, K-: electroproduction, DESY HERA Stor, positron deuteron: deep inelastic scattering, positron deuteron: inclusive reaction, pi-: electroproduction, K+: electroproduction, flavor: asymmetry, quark: helicity, spin: asymmetry, experimental results
Abstract

Physical review letters 92(1), 012005 (2004). doi:10.1103/PhysRevLett.92.012005, Double-spin asymmetries of semi-inclusive cross sections for the production of identified pions and kaons have been measured in deep-inelastic scattering of polarized positrons on a polarized deuterium target. Five helicity distributions including those for three sea quark flavors were extracted from these data together with re-analyzed previous data for identified pions from a hydrogen target. These distributions are consistent with zero for all three sea flavors. A recently predicted flavor asymmetry in the polarization of the light quark sea appears to be disfavored by the data., Published by APS, College Park, Md.

Published
2004
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18. Nuclear polarization of molecular hydrogen recombined on a non-metallic surface

Author

Airapetian, A., Akopov, N., Avetissian, E., Makins, N. C. R., Marianski, B., Marukian, H., Masoli, F., Mexner, V., Meyners, N., Mikloukho, O., Miller, C. A., Miyachi, Y., Muccifora, V., Bailey, P., Nagaitsev, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. D., Oganessyan, K., Ohsuga, H., Pickert, N., Potashov, S., Baturin, V., Potterveld, David H., Raithel, M., Reggiani, D., Reimer, P. E., Reischl, A., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomian, A., Baumgarten, C., Rubacek, L., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanjiev, I., Savin, Igor A., Scarlett, C., Schill, C., Schnell, G., Schuler, K. P., Beckmann, M., Schwind, A., Seele, J., Seidl, R., Seitz, B., Shanidze, R., Shearer, C., Shibata, T. A., Shutov, V., Simani, M. C., Sinram, K., Belostotsky, S., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stosslein, U., Tait, P., Tanaka, H., Taroian, S., Bernreuther, S., Chuiko, B., Terkulov, A., Tkabladze, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., van der Nat, P., van der Steenhoven, G., Vetterli, M. C., Vikhrov, V., Bianchi, N., Vincter, M. G., Vogel, C., Vogt, M., Volmer, J., Weiskopf, C., Wendland, J., Wilbert, J., Wise, T., Ybeles Smit, G., Zihlmann, B., Blok, H. P., Zohrabian, H., Zupranski, P., HERMES Collaboration, Bottcher, H., Akopov, Z., Borissov, A., Borisenko, A., Bouwhuis, M., Brack, J., Brull, A., Bryzgalov, V., Capitani, G. P., Chiang, H. C., Ciullo, G., Contalbrigo, M., Amarian, M., Court, G., Dalpiaz, P. F., De Leo, R., De Nardo, L., De Sanctis, E., Devitsin, E., Di Nezza, P., Duren, M., Ehrenfried, M., Elalaoui-Moulay, A., Ammosov, V. V., Elbakian, G., Ellinghaus, F., Elschenbroich, U., Ely, J., Fabbri, R., Fantoni, A., Feshchenko, A., Felawka, L., Fox, B., Franz, J., Andrus, A., Frullani, S., Gapienko, G., Gapienko, V., Garibaldi, F., Garrow, K., Garutti, E., Gaskell, D., Gavrilov, G., Gharibyan, V., Graw, G., Aschenauer, E. C., Grebenyuk, O., Greeniaus, L. G., Gregor, I. M., Haeberli, W., Hafidi, K., Hartig, M., Hasch, D., Heesbeen, D., Henoch, M., Hertenberger, R., Augustyniak, W., Hesselink, W. H. A., Hillenbrand, A., Hoek, M., Holler, Y., Hommez, B., Yarygin, G., Ivanilov, A., Izotov, A., Jackson, H. E., Jgoun, A., Avakian, R., Kaiser, R., Kinney, E., Kiselev, A., Kolster, H., Konigsmann, Kay, Kopytin, M., Korotkov, V., Kozlov, V., Krauss, B., Krivokhizhin, V. G., Avetissian, A., Lagamba, L., Lapikas, Louk, Laziev, A., Lenisa, P., Liebing, P., Linden-Levy, L. A., Lipka, K., Lorenzon, W., Lu, J., and Maiheu, B.

Subjects
fabrication [polarized target], DESY HERA Stor, 13.88.+e, molecule [hydrogen], polarized target [hydrogen], 39.10.+j, measurement [polarization], 34.09.+q, ddc:530, silicon [plastics], HERMES, surface [plastics], 29.25.P
Abstract

The nuclear polarization of ${\rm H}_2$ molecules formed by recombination of nuclear polarized H atoms on

Published
2004
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19. Nuclear polarization of molecular hydrogen recombined on a non-metallic surface

Author

Airapetian, A., Akopov, N., Akopov, Z., Amarian, M., Ammosov, V. V., Andrus, A., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetissian, E., Bailey, P., Baturin, V., Baumgarten, C., Beckmann, M., Belostotsky, S., Bernreuther, S., Bianchi, N., Blok, H. P., Bottcher, H., Borissov, A., Borisenko, A., Bouwhuis, M., Brack, J., Brull, A., Bryzgalov, V., Capitani, G. P., Chiang, H. C., Ciullo, G., Contalbrigo, M., Court, G., Dalpiaz, P. F., De Leo, R., De Nardo, L., De Sanctis, E., Devitsin, E., Di Nezza, P., Duren, M., Ehrenfried, M., Elalaoui-Moulay, A., Elbakian, G., Ellinghaus, F., Elschenbroich, U., Ely, J., Fabbri, R., Fantoni, A., Feshchenko, A., Felawka, L., Fox, B., Franz, J., Frullani, S., Gapienko, G., Gapienko, V., Garibaldi, F., Garrow, K., Garutti, E., Gaskell, D., Gavrilov, G., Gharibyan, V., Graw, G., Grebenyuk, O., Greeniaus, L. G., Gregor, I. M., Haeberli, W., Hafidi, K., Hartig, M., Hasch, D., Heesbeen, D., Henoch, M., Hertenberger, R., Hesselink, W. H. A., Hillenbrand, A., Hoek, M., Holler, Y., Hommez, B., Yarygin, G., Ivanilov, A., Izotov, A., Jackson, H. E., Jgoun, A., Kaiser, R., Kinney, E., Kiselev, A., Kolster, H., Konigsmann, Kay, Kopytin, M., Korotkov, V., Kozlov, V., Krauss, B., Krivokhizhin, V. G., Lagamba, L., Lapikas, Louk, Laziev, A., Lenisa, P., Liebing, P., Linden-Levy, L. A., Lipka, K., Lorenzon, W., Lu, J., Maiheu, B., Makins, N. C. R., Marianski, B., Marukian, H., Masoli, F., Mexner, V., Meyners, N., Mikloukho, O., Miller, C. A., Miyachi, Y., Muccifora, V., Nagaitsev, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. D., Oganessyan, K., Ohsuga, H., Pickert, N., Potashov, S., Potterveld, David H., Raithel, M., Reggiani, D., Reimer, P. E., Reischl, A., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomian, A., Rubacek, L., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanjiev, I., Savin, Igor A., Scarlett, C., Schill, C., Schnell, G., Schuler, K. P., Schwind, A., Seele, J., Seidl, R., Seitz, B., Shanidze, R., Shearer, C., Shibata, T. A., Shutov, V., Simani, M. C., Sinram, K., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stosslein, U., Tait, P., Tanaka, H., Taroian, S., Chuiko, B., Terkulov, A., Tkabladze, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., van der Nat, P., van der Steenhoven, G., Vetterli, M. C., Vikhrov, V., Vincter, M. G., Vogel, C., Vogt, M., Volmer, J., Weiskopf, C., Wendland, J., Wilbert, J., Wise, T., Ybeles Smit, G., Zihlmann, B., Zohrabian, H., Zupranski, P., and HERMES Collaboration

Subjects
hydrogen: molecule, plastics: surface, plastics: silicon, DESY HERA Stor, hydrogen: polarized target, 13.88.+e, polarization: measurement, 39.10.+j, 34.09.+q, polarized target: fabrication, HERMES, 29.25.P
Abstract

The nuclear polarization of ${\rm H}_2$ molecules formed by recombination of nuclear polarized H atoms on

Published
2004
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20. Single spin azimuthal asymmetries in electroproduction of neutral pions in semiinclusive deep inelastic scattering

Author

Airapetian, A., Akopov, N., Akopov, Z., Amarian, M., Aschenauer, E. C., Avakian, H., Avakian, R., Avetissian, A., Avetissian, E., Bailey, P., Bains, B., Baturin, V., Baumgarten, C., Beckmann, M., Belostotski, S., Bernreuther, S., Bianchi, N., Bottcher, H., Borissov, A., Bouhali, O., Bouwhuis, M., Brack, J., Brauksiepe, S., Bruckner, W., Brull, A., Brunn, I., Bulten, H. J., Capitani, G. P., Chumney, P., Cisbani, E., Ciullo, G., Court, G. R., Dalpiaz, P. F., De Leo, R., De Nardo, L., De Sanctis, E., De Schepper, D., Devitsin, E., De Witt Huberts, P. K. A., Di Nezza, P., Djordjadze, V., Duren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Ely, J., Fantoni, A., Fechtchenko, A., Felawka, L., Filippone, B. W., Fischer, H., Fox, B., Franz, J., Frullani, S., Garber, Y., Garibaldi, F., Garutti, E., Gavrilov, G., Gharibyan, V., Golendukhin, A., Graw, G., Grebeniouk, O., Green, P. W., Greeniaus, L. G., Gute, A., Haeberli, W., Hafidi, K., Hartig, M., Hasch, D., Heesbeen, D., Heinsius, F. H., Henoch, M., Hertenberger, R., Hesselink, W. H. A., Hofman, G., Holler, Y., Holt, R. J., Hommez, B., Iarygin, G., Izotov, A., Jackson, H. E., Jgoun, A., Jung, P., Kaiser, R., Kanesaka, J., Kinney, E., Kisselev, A., Kitching, P., Kobayashi, H., Koch, N., Konigsmann, K., Kolster, H., Korotkov, V., Kotik, E., Kozlov, V., Krauss, B., Krivokhijine, V. G., Kyle, G., Lagamba, L., Laziev, A., Lenisa, P., Liebing, P., Lindemann, T., Lorenzon, W., Maas, A., Makins, N. C. R., Marukyan, H., Masoli, F., McAndrew, M., McIlhany, K., Meissner, F., Menden, F., Meyners, N., Mikloukho, O., Miller, C. A., Milner, R., Muccifora, V., Mussa, R., Nagaitsev, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaeva, K., Nowak, W.-D., Oganessyan, K., O'Neill, T. G., Owen, B. R., Pate, S. F., Potashov, S., Potterveld, D. H., Raithel, M., Rakness, G., Rappoport, V., Redwine, R., Reggiani, D., Reolon, A. R., Rith, K., Robinson, D., Rostomyan, A., Ruh, M., Ryckbosch, D., Sakemi, Y., Sanjiev, I., Sato, F., Savin, I., Scarlett, C., Schafer, A., Schill, C., Schmidt, F., Schnell, G., Schuler, K. P., Schwind, A., Seibert, J., Seitz, B., Shibata, T.-A., Shutov, V., Simani, M. C., Simon, A., Sinram, K., Steffens, E., Steijger, J. J. M., Stewart, J., Stosslein, U., Suetsugu, K., Taroian, S., Terkulov, A., Teryaev, O., Tessarin, S., 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., Vincter, M. G., Visser, J., Weiskopf, C., Wendland, J., Wilbert, J., Wise, T., Yen, S., Yoneyama, S., and Zohrabian, H.

Subjects
positron p: deep inelastic scattering, polarization: longitudinal, HERMES, transverse momentum dependence, fragmentation function, energy dependence, x-dependence, DESY HERA Stor, 27.5 GeV, p: polarized target, pi0: electroproduction, analyzing power, polarization: transverse, quark: polarization, spin: asymmetry, experimental results
Abstract

Physical review / D 64(9), 097101 (2001). doi:10.1103/PhysRevD.64.097101, A single-spin asymmetry in the azimuthal distribution of neutral pions relative to the lepton scattering plane has been measured for the first time in deep-inelastic scattering of positrons off longitudinally polarized protons. The analysing power in the sin(phi) moment of the cross section is 0.019 +/- 0.007(stat.) +/- 0.003(syst.). This result is compared to single-spin asymmetries for charged pion production measured in the same kinematic range. The pi^0 asymmetry is of the same size as the pi^+ asymmetry and shows a similar dependence on the relevant kinematic variables. The asymmetry is described by a phenomenological calculation based on a fragmentation function that represents sensitivity to the transverse polarization of the struck quark., Published by Inst., Woodbury, NY

Published
2001
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21. Measurement of longitudinal spin transfer to $\Lambda$ hyperons in deep inelastic lepton scattering

Author

Airapetian, A., Akopov, N., Amarian, M., Aschenauer, E. C., Avakian, H., Avakian, R., Avetissian, A., Bains, B., Baumgarten, C., Beckmann, M., Belostotski, S., Belz, J. E., Benisch, Th., Bernreuther, S., Bianchi, N., Blouw, J., Bottcher, H., Borissov, A., Bouwhuis, M., Brack, J., Brauksiepe, S., Braun, B., Bray, B., Brons, S., Bruckner, W., Brull, A., Bruins, E. E. W., Bulten, H. J., Capitani, G. P., 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., Duren, M., Dvoredsky, A., Elbakian, G., Ely, J., Fantoni, A., Fechtchenko, A., Ferstl, M., Fiedler, K., Filippone, B. W., Fischer, H., Fox, B., Franz, J., Frullani, S., Funk, M.-A., Garber, Y., Gao, H., Garibaldi, F., Gavrilov, G., Geiger, P., Gharibyan, V., Golendukhin, A., Graw, G., Grebeniouk, O., Green, P. W., Greeniaus, L. G., Grosshauser, C., Guidal, M., Gute, A., Gyurjyan, V., Haas, J. P., Haeberli, W., Hausser, O., Hansen, J.-O., Hartig, M., Hasch, D., Heinsius, F. H., Henderson, R., Henoch, M., Hertenberger, R., Holler, Y., Holt, R. J., Hoprich, W., Ihssen, H., Iodice, M., Izotov, A., Jackson, H. E., Jgoun, A., Kaiser, R., Kinney, E., Kirsch, M., Kisselev, A., Kitching, P., Kobayashi, H., Koch, N., Konigsmann, K., Kolstein, M., Kolster, H., Korotkov, V., Korsch, W., Kozlov, V., Kramer, L. H., Krivokhijine, V. G., Kurisuno, M., Kyle, G., Lachnit, W., Lenisa, P., Lorenzon, W., Makins, N. C. R., Manaenkov, S. I., Martens, F. K., Martin, J. W., Masoli, F., Mateos, A., McAndrew, M., McIlhany, K., McKeown, R. D., Meissner, F., Menden, F., Metz, A., Meyners, N., Mikloukho, O., Miller, C. A., Miller, M. A., Milner, R., Most, A., Muccifora, V., Mussa, R., Nagaitsev, A., Naryshkin, Y., Nathan, A. M., Neunreither, F., Niczyporuk, J. M., Nowak, W.-D., Nupieri, M., O'Neill, T. G., Openshaw, R., Ouyang, J., Owen, B. R., Papavassiliou, V., Pate, S. F., Pitt, M., Potashov, S., Potterveld, D. H., Rakness, G., Reali, A., Redwine, R., Reolon, A. R., Ristinen, R., Rith, K., Rossi, P., Rudnitsky, S., Ruh, M., Ryckbosch, D., Sakemi, Y., Savin, I., Scarlett, C., Schmidt, F., Schmitt, H., Schnell, G., Schuler, K. P., Schwind, A., Seibert, J., Shibata, T.-A., Shibatani, K., Shin, T., Shutov, V., Simani, C., Simon, A., Sinram, K., Slavich, P., Spengos, M., Steffens, E., Stenger, J., Stewart, J., Stosslein, U., Sutter, M., Tallini, H., Taroian, S., Terkulov, 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., Vincter, M. G., Visser, J., Volk, E., Wander, W., Wendland, J., Williamson, S. E., Wise, T., Woller, K., Yoneyama, S., and Zohrabian, H.

Subjects
positron: polarized beam, Lambda: electroproduction, quark model parton, positron p: deep inelastic scattering, up: fragmentation, Lambda: polarization, HERMES, up: polarization, +p+pi%22">Lambda --> p pi, helicity: conservation law, DESY HERA Stor, 27.5 GeV, mass spectrum: (p pi-), angular distribution, +Lambda%22">positron p --> Lambda, experimental results
Abstract

Physical review / D 64(11), 112005 (2001). doi:10.1103/PhysRevD.64.112005, Spin transfer in deep-inelastic Lambda electroproduction has been studied with the HERMES detector using the 27.6 GeV polarized positron beam in the HERA storage ring. For an average fractional energy transfer = 0.45, the longitudinal spin transfer from the virtual photon to the Lambda has been extracted. The spin transfer along the Lambda momentum direction is found to be 0.11 +/- 0.17 (stat) +/- 0.03 (sys); similar values are found for other possible choices for the longitudinal spin direction of the Lambda. This result is the most precise value obtained to date from deep-inelastic scattering with charged lepton beams, and is sensitive to polarized up quark fragmentation to hyperon states. The experimental result is found to be in general agreement with various models of the Lambda spin content, and is consistent with the assumption of helicity conservation in the fragmentation process., Published by Inst., Woodbury, NY

Published
2001
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22. Measurement of the beam spin azimuthal asymmetry associated with deeply virtual Compton scattering

Author

Airapetian, A., Akopov, N., Akopov, Z., Amarian, M., Aschenauer, E. C., Avakian, H., Avakian, R., Avetissian, A., Avetissian, E., Bailey, P., Bains, B., Baturin, V., Baumgarten, C., Beckmann, M., Belostotski, S., Bernreuther, S., Bianchi, N., Bottcher, H., Borissov, A., Bouhali, O., Bouwhuis, M., Brack, J., Brauksiepe, S., Bruckner, W., Brull, A., Brunn, I., Bulten, H. J., Capitani, G. P., Chumney, P., Cisbani, E., Ciullo, G., Court, G. R., Dalpiaz, P. F., De Leo, R., De Nardo, L., De Sanctis, E., De Schepper, D., Devitsin, E., De Witt Huberts, P. K. A., Di Nezza, P., Duren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Ely, J., Fabbri, R., Fantoni, A., Fechtchenko, A., Felawka, L., Filippone, B. W., Fischer, H., Fox, B., Franz, J., Frullani, S., Garber, Y., Garibaldi, F., Garutti, E., Gavrilov, G., Gharibyan, V., Golendukhin, A., Graw, G., Grebeniouk, O., Green, P. W., Greeniaus, L. G., Gute, A., Haeberli, W., Hafidi, K., Hartig, M., Hasch, D., Heesbeen, D., Heinsius, F. H., Henoch, M., Hertenberger, R., Hesselink, W. H. A., Hofman, G., Holler, Y., Holt, R. J., Hommez, B., Iarygin, G., Izotov, A., Jackson, H. E., Jgoun, A., Jung, P., Kaiser, R., Kanesaka, J., Kinney, E., Kisselev, A., Kitching, P., Kobayashi, H., Koch, N., Konigsmann, K., Kolster, H., Korotkov, V., Kotik, E., Kozlov, V., Krauss, B., Krivokhijine, V. G., Kyle, G., Lagamba, L., Laziev, A., Lenisa, P., Liebing, P., Lindemann, T., Lorenzon, W., Maas, A., Makins, N. C. R., Marukyan, H., Masoli, F., McAndrew, M., McIlhany, K., Meissner, F., Menden, F., Meyners, N., Mikloukho, O., Miller, C. A., Milner, R., Muccifora, V., Mussa, R., Nagaitsev, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaeva, K., Nowak, W.-D, Oganessyan, K., O'Neill, T. G., Owen, B. R., Pate, S. F., Potashov, S., Potterveld, D. H., Raithel, M., Rakness, G., Rappoport, V., Redwine, R., Reggiani, D., Reolon, A. R., Rith, K., Robinson, D., Rostomyan, A., Ruh, M., Ryckbosch, D., Sakemi, Y., Sanjiev, I., Sato, F., Savin, I., Scarlett, C., Schafer, A., Schill, C., Schmidt, F., Schnell, G., Schuler, K. P., Schwind, A., Seibert, J., Seitz, B., Shibata, T.-A., Shutov, V., Simani, M. C., Simon, A., Sinram, K., Steffens, E., Steijger, J. J. M., Stewart, J., Stosslein, U., Suetsugu, K., Taroian, S., Terkulov, A., Tessarin, S., Thomas, E., Tipton, B., Tytgat, M., Urciuoli, G. M., Van Den Brand, J. F. J., Van Steenhoven, G., Van Vyver, R., Van Hunen, J. J., Vetterli, M. C., Vikhrov, V., Vincter, M. G., Visser, J., Weiskopf, C., Wendland, J., Wilbert, J., Wise, T., Yen, S., Yoneyama, S., and Zohrabian, H.

Subjects
positron: polarized beam, angular distribution: asymmetry, positron p: deep inelastic scattering, polarization: longitudinal, approximation: Bethe-Heitler, interference, HERMES, photon: electroproduction, helicity: dependence, DESY HERA Stor, analyzing power, Compton scattering: off-shell, 26.7 GeV, experimental results
Abstract

Physical review letters 87(18), 182001 (2001). doi:10.1103/PhysRevLett.87.182001, The beam-spin asymmetry in hard electroproduction of photons has been measured for the first time. The data have been accumulated by the HERMES experiment at DESY using the HERA 27.6 GeV longitudinally polarized positron beam and an unpolarized hydrogen gas target. The asymmetry in the azimuthal distribution of the produced photons in the angle phi relative to the lepton scattering plane was determined with respect to the helicity state of the incoming positron beam. The beam-spin analyzing power in the sin(phi) moment was measured to be -0.23 +/- 0.04(stat) +/- 0.03(syst) in the missing-mass range below 1.7 GeV. The observed asymmetry is attributed to the interference of the Bethe-Heitler and deeply-virtual Compton scattering processes., Published by APS, College Park, Md.

Published
2001
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23. Measurement of the spin asymmetry in the photoproduction of pairs of high $\mathrm{p_T}$ hadrons at HERMES

Author

Airapetian, A., Akopov, N., Amarian, M., Aschenauer, E. C., Avakian, H., Avakian, R., Avetissian, A., Bains, B., Baumgarten, C., Beckmann, M., Belostotski, S., Belz, J. E., Benisch, Th., Bernreuther, S., Bianchi, N., Blouw, J., Bottcher, H., Borissov, A., Brack, J., Brauksiepe, S., Braun, B., Bruckner, W., Brull, A., Bulten, H. J., Capitani, G. P., 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., Duren, M., Dvoredsky, A., Elbakian, G., Ely, J., Fantoni, A., Ferstl, M., Fiedler, K., Filippone, B. W., Fischer, H., Fox, B., Franz, J., Frullani, S., Funk, M.-A., Garber, Y., Garibaldi, F., Gavrilov, G., Geiger, P., Gharibyan, V., Golendukhin, A., Graw, G., Grebeniouk, O., Green, P. W., Greeniaus, L. G., Grosshauser, C., Guidal, M., Gute, A., Haeberli, W., Hansen, J.-O., Hasch, D., Hausser, O., Heinsius, F. H., Henderson, R., Henoch, M., Hertenberger, R., Holler, Y., Holt, R. J., Hoprich, W., Ihssen, H., Iodice, M., Izotov, A., Jackson, H. E., Jgoun, A., Kaiser, R., Kinney, E., Kisselev, A., Kitching, P., Kobayashi, H., Koch, N., Konigsmann, K., Kolstein, M., Kolster, H., Korotkov, V., Korsch, W., Kozlov, V., Kramer, L. H., Kurisuno, M., Kyle, G., Lachnit, W., Lorenzon, W., Makins, N. C. R., Martens, F. K., Martin, J. W., Masoli, F., Mateos, A., McAndrew, M., McIlhany, K., McKeown, R. D., Meissner, F., Menden, F. M., Metz, A., Meyners, N., Mikloukho, O., Miller, C. A., Miller, M. A., Milner, R., Most, A., Muccifora, V., Naryshkin, Y., Nathan, A. M., Neunreither, F., Niczyporuk, M., Nowak, W.-D., O'Neill, T. G., Openshaw, R., Ouyang, J., Owen, B. R., Pate, S. F., Potashov, S., Potterveld, D. H., Rakness, G., Redwine, R., Reolon, A. R., Ristinen, R., Rith, K., Rossi, P., Rudnitsky, S., Ruh, M., Ryckbosch, D., Sakemi, Y., Scarlett, C., Schafer, A., Schmidt, F., Schmitt, H., Schnell, G., Schuler, K. P., Schwind, A., Seibert, J., Shibata, T.-A., Shibatani, K., Shin, T., Shutov, V., Simani, C., Simon, A., Sinram, K., Slavich, P., Spengos, M., Steffens, E., Stenger, J., Stewart, J., Stoesslein, U., Sutter, M., Tallini, H., Taroian, S., Terkulov, A., Tipton, B., Tytgat, M., Uriuoli, G. M., Van De Vyver, R., Van Den Brand, J. F. J., Van Der Steenhoven, G., Van Hunen, J. J., Vetterli, M. C., Vikhrov, V., Vincter, M. G., Visser, J., Volk, E., Wander, W., Wendland, J., Williamson, S. E., Wise, T., Woller, K., Yoneyama, S., and Zohrabian, H.

Subjects
positron: polarized beam, DESY HERA Stor, 27.5 GeV, polarization: asymmetry, positron p: deep inelastic scattering, +hadron%2B+hadron-+positron+anything%22">positron p --> hadron+ hadron- positron anything, polarization: longitudinal, polarized target: internal, HERMES, gluon: polarization, hadron: pair production, experimental results
Abstract

Physical review letters 84(12), 2584 - 2588 (2000). doi:10.1103/PhysRevLett.84.2584, We present a measurement of the longitudinal spin asymmetry A_|| in photoproduction of pairs of hadrons with high transverse momentum p_T. Data were accumulated by the HERMES experiment using a 27.5 GeV polarized positron beam and a polarized hydrogen target internal to the HERA storage ring. For h+h- pairs with p_T^h_1 > 1.5 GeV/c and p_T^h_2 > 1.0 GeV/c, the measured asymmetry is A_|| = -0.28 +/- 0.12 (stat.) +/- 0.02 (syst.). This negative value is in contrast to the positive asymmetries typically measured in deep inelastic scattering from protons, and is interpreted to arise from a positive gluon polarization., Published by APS, College Park, Md.

Published
2000
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24. Measurement of the spin asymmetry in the photoproduction of pairs of high $\mathrm{p_T}$ hadrons at HERMES

Author

Airapetian, A., Akopov, N., Belostotski, S., McIlhany, K., McKeown, R. D., Meissner, F., Menden, F. M., Metz, A., Meyners, N., Mikloukho, O., Miller, C. A., Miller, M. A., Milner, R., Belz, J. E., Most, A., Muccifora, V., Naryshkin, Y., Nathan, A. M., Neunreither, F., Niczyporuk, M., Nowak, W.-D., O'Neill, T. G., Openshaw, R., Ouyang, J., Benisch, Th., Owen, B. R., Pate, S. F., Potashov, S., Potterveld, D. H., Rakness, G., Redwine, R., Reolon, A. R., Ristinen, R., Rith, K., Rossi, P., Bernreuther, S., Rudnitsky, S., Ruh, M., Ryckbosch, D., Sakemi, Y., Scarlett, C., Schafer, A., Schmidt, F., Schmitt, H., Schnell, G., Schuler, K. P., Bianchi, N., Schwind, A., Seibert, J., Shibata, T.-A., Shibatani, K., Shin, T., Shutov, V., Simani, C., Simon, A., Sinram, K., Slavich, P., Blouw, J., Spengos, M., Steffens, E., Stenger, J., Stewart, J., Stoesslein, U., Sutter, M., Tallini, H., Taroian, S., Terkulov, A., Tipton, B., Bottcher, H., Tytgat, M., Uriuoli, G. M., van de Vyver, R., van den Brand, J. F. J., van der Steenhoven, G., van Hunen, J. J., Vetterli, M. C., Vikhrov, V., Vincter, M. G., Visser, J., Borissov, A., Volk, E., Wander, W., Wendland, J., Williamson, S. E., Wise, T., Woller, K., Yoneyama, S., Zohrabian, H., HERMES Collaboration, Brack, J., Brauksiepe, S., Amarian, M., Braun, B., Bruckner, W., Brull, A., Bulten, H. J., Capitani, G. P., Carter, P., Chumney, P., Cisbani, E., Court, G. R., Dalpiaz, P. F., Aschenauer, E. C., De Sanctis, E., De Schepper, D., Devitsin, E., de Witt Huberts, P. K. A., Di Nezza, P., Duren, M., Dvoredsky, A., Elbakian, G., Ely, J., Fantoni, A., Avakian, H., Ferstl, M., Fiedler, K., Filippone, B. W., Fischer, H., Fox, B., Franz, J., Frullani, S., Funk, M.-A., Garber, Y., Garibaldi, F., Avakian, R., Gavrilov, G., Geiger, P., Gharibyan, V., Golendukhin, A., Graw, G., Grebeniouk, O., Green, P. W., Greeniaus, L. G., Grosshauser, C., Guidal, M., Avetissian, A., Gute, A., Haeberli, W., Hansen, J.-O., Hasch, D., Hausser, 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., Konigsmann, K., Kolstein, M., Kolster, H., Korotkov, V., Korsch, W., Kozlov, V., Kramer, L. H., Beckmann, M., Kurisuno, M., Kyle, G., Lachnit, W., Lorenzon, W., Makins, N. C. R., Martens, F. K., Martin, J. W., Masoli, F., Mateos, A., and McAndrew, M.

Subjects
internal [polarized target], longitudinal [polarization], +hadron%2B+hadron-+positron+anything%22">positron p --> hadron+ hadron- positron anything, HERMES, Astrophysics::Cosmology and Extragalactic Astrophysics, polarization [gluon], DESY HERA Stor, 27.5 GeV, pair production [hadron], asymmetry [polarization], ddc:550, High Energy Physics::Experiment, deep inelastic scattering [positron p], polarized beam [positron], Nuclear Experiment, experimental results
Abstract

We present a measurement of the longitudinal spin asymmetry A_|| in photoproduction of pairs of hadrons with high transverse momentum p_T. Data were accumulated by the HERMES experiment using a 27.5 GeV polarized positron beam and a polarized hydrogen target internal to the HERA storage ring. For h+h- pairs with p_T^h_1 > 1.5 GeV/c and p_T^h_2 > 1.0 GeV/c, the measured asymmetry is A_|| = -0.28 +/- 0.12 (stat.) +/- 0.02 (syst.). This negative value is in contrast to the positive asymmetries typically measured in deep inelastic scattering from protons, and is interpreted to arise from a positive gluon polarization.

Published
2000
Full Text
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