P. Zupranski - The Andrzej Soltan Institute for Nuclear Studies

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P. Zupranski
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The Andrzej Soltan Institute for Nuclear Studies
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Nuclear Experiment (33)
 
High Energy Physics - Experiment (31)
 
High Energy Physics - Phenomenology (6)
 
Physics - Accelerator Physics (3)
 
Nuclear Theory (1)
 
Physics - Instrumentation and Detectors (1)

Publications Authored By P. Zupranski

This letter reports the successful use of feedback from a spin polarization measurement to the revolution frequency of a 0.97 GeV/$c$ bunched and polarized deuteron beam in the Cooler Synchrotron (COSY) storage ring in order to control both the precession rate ($\approx 121$ kHz) and the phase of the horizontal polarization component. Real time synchronization with a radio frequency (rf) solenoid made possible the rotation of the polarization out of the horizontal plane, yielding a demonstration of the feedback method to manipulate the polarization. Read More

Precision experiments, such as the search for electric dipole moments of charged particles using storage rings, demand for an understanding of the spin dynamics with unprecedented accuracy. The ultimate aim is to measure the electric dipole moments with a sensitivity up to 15 orders in magnitude better than the magnetic dipole moment of the stored particles. This formidable task requires an understanding of the background to the signal of the electric dipole from rotations of the spins in the spurious magnetic fields of a storage ring. Read More

Exclusive measurements of the quasi-free $pn \to pp\pi^-$ and $pp \to pp\pi^0$ reactions have been performed by means of $pd$ collisions at $T_p$ = 1.2 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region $T_p = 0. Read More

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$^2$Read More

The search for 4He-eta bound states was performed with the WASA-at-COSY facility via the measurement of the excitation function for the dd->3He n pi0 and dd->3He p pi- processes. The beam momentum was varied continuously between 2.127 GeV/c and 2. Read More

Using the production reactions $pd\to {}^3\mbox{He}\,\omega$ and $pp\to pp\omega$, the Dalitz plot distribution for the $\omega \to \pi^+ \pi^- \pi^0$ decay is studied with the WASA detector at COSY, based on a combined data sample of $ (4.408\pm 0.042) \times 10^4$ events. Read More

Various theoretical calculations based on QCD or hadronic interactions predict that in addition to the recently observed dibaryon resonance $d^*(2380)$ with $I(J^P) = 0(3^+)$ there should also exist a dibaryon resonance with mirrored quantum numbers $I(J^P) = 3(0^+)$. We report here on a search for such a $NN$-decoupled state in data on the $pp \to pp\pi^+\pi^+\pi^-\pi^-$ reaction. Since no clear-cut evidence has been found, we give upper limits for the production cross section of such a resonance in the mass range 2280 - 2500 MeV. Read More

We report on a high-statistics measurement of the most basic double pionic fusion reaction $\vec{n}p \to d\pi^0\pi^0$ over the energy region of the $d^*(2380)$ resonance by use of a polarized deuteron beam and observing the double fusion reaction in the quasifree scattering mode. The measurements were performed with the WASA detector setup at COSY. The data reveal substantial analyzing powers and confirm conclusions about the $d^*$ resonance obtained from unpolarized measurements. Read More

The WASA-at-COSY experiment has collected $3\times10^{7}$ events with $\eta$-mesons produced via the reaction $pd\rightarrow{^{3}\textrm{He}}\eta$ at $\textrm{T} = 1.0 \textrm{GeV}$. Using this data set, we evaluate the branching ratios of the decays $\eta\to\pi^{+}\pi^{-}\gamma$, $\eta\to e^{+}e^{-}\gamma$, $\eta\to\pi^{+}\pi^{-}e^{+}e^{-}$ and $\eta\to e^{+}e^{-}e^{+}e^{-}$. Read More

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. Read More

2015May
Authors: HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, S. Belostotski, N. Bianchi, H. P. Blok, A. Borissov, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Düren, G. Elbakian, F. Ellinghaus, E. Etzelmüller, R. Fabbri, A. Fantoni, L. Felawka, S. Frullani, G. Gapienko, V. Gapienko, J. Garay García, F. Garibaldi, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Hartig, D. Hasch, Y. Holler, I. Hristova, Y. Imazu, A. Ivanilov, H. E. Jackson, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, V. Korotkov, V. Kozlov, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, L. Lapikás, I. Lehmann, P. Lenisa, A. López Ruiz, W. Lorenzon, X. -G. Lu, B. -Q. Ma, D. Mahon, N. C. R. Makins, Y. Mao, B. Marianski, A. Martinez de la Ossa, H. Marukyan, Y. Miyachi, A. Movsisyan, M. Murray, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W. -D. Nowak, L. L. Pappalardo, R. Perez-Benito, A. Petrosyan, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, A. Schäfer, G. Schnell, B. Seitz, T. -A. Shibata, V. Shutov, M. Stahl, M. Stancari, M. Statera, J. J. M. Steijger, S. Taroian, A. Terkulov, R. Truty, A. Trzcinski, M. Tytgat, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, V. Vikhrov, I. Vilardi, S. Wang, S. Yaschenko, Z. Ye, S. Yen, B. Zihlmann, P. Zupranski

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. Read More

2015Apr
Affiliations: 1JEDI collaboration, 2JEDI collaboration, 3JEDI collaboration, 4JEDI collaboration, 5JEDI collaboration, 6JEDI collaboration, 7JEDI collaboration, 8JEDI collaboration, 9JEDI collaboration, 10JEDI collaboration, 11JEDI collaboration, 12JEDI collaboration, 13JEDI collaboration, 14JEDI collaboration, 15JEDI collaboration, 16JEDI collaboration, 17JEDI collaboration, 18JEDI collaboration, 19JEDI collaboration, 20JEDI collaboration, 21JEDI collaboration, 22JEDI collaboration, 23JEDI collaboration, 24JEDI collaboration, 25JEDI collaboration, 26JEDI collaboration, 27JEDI collaboration, 28JEDI collaboration, 29JEDI collaboration, 30JEDI collaboration, 31JEDI collaboration, 32JEDI collaboration, 33JEDI collaboration, 34JEDI collaboration, 35JEDI collaboration, 36JEDI collaboration, 37JEDI collaboration, 38JEDI collaboration, 39JEDI collaboration, 40JEDI collaboration, 41JEDI collaboration, 42JEDI collaboration, 43JEDI collaboration, 44JEDI collaboration, 45JEDI collaboration, 46JEDI collaboration, 47JEDI collaboration, 48JEDI collaboration, 49JEDI collaboration, 50JEDI collaboration, 51JEDI collaboration, 52JEDI collaboration, 53JEDI collaboration, 54JEDI collaboration, 55JEDI collaboration, 56JEDI collaboration, 57JEDI collaboration, 58JEDI collaboration, 59JEDI collaboration, 60JEDI collaboration, 61JEDI collaboration, 62JEDI collaboration, 63JEDI collaboration, 64JEDI collaboration, 65JEDI collaboration, 66JEDI collaboration, 67JEDI collaboration, 68JEDI collaboration, 69JEDI collaboration, 70JEDI collaboration, 71JEDI collaboration, 72JEDI collaboration, 73JEDI collaboration, 74JEDI collaboration, 75JEDI collaboration, 76JEDI collaboration, 77JEDI collaboration, 78JEDI collaboration, 79JEDI collaboration, 80JEDI collaboration, 81JEDI collaboration, 82JEDI collaboration, 83JEDI collaboration, 84JEDI collaboration, 85JEDI collaboration, 86JEDI collaboration, 87JEDI collaboration, 88JEDI collaboration, 89JEDI collaboration, 90JEDI collaboration, 91JEDI collaboration, 92JEDI collaboration, 93JEDI collaboration, 94JEDI collaboration, 95JEDI collaboration, 96JEDI collaboration, 97JEDI collaboration, 98JEDI collaboration, 99JEDI collaboration, 100JEDI collaboration, 101JEDI collaboration

A new method to determine the spin tune is described and tested. In an ideal planar magnetic ring, the spin tune - defined as the number of spin precessions per turn - is given by $\nu_s = \gamma G$ (gamma is the Lorentz factor, $G$ the magnetic anomaly). For 970 MeV/c deuterons coherently precessing with a frequency of ~120 kHz in the Cooler Synchrotron COSY, the spin tune is deduced from the up-down asymmetry of deuteron carbon scattering. Read More

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 $68_{-31}^{+98}\text{(stat)}\pm13\text{(sys)}$. Read More

Exclusive measurements of the quasi-free $np \to np\pi^0\pi^0$ reaction have been performed by means of $dp$ collisions at $T_d$ = 2.27 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region $\sqrt s$ = (2. Read More

Exclusive and kinematically complete measurements of the double pionic fusion to $^3$He have been performed in the energy region of the so-called ABC effect, which denotes a pronounced low-mass enhancement in the $\pi\pi$-invariant mass spectrum. The experiments were carried out with the WASA detector setup at COSY. Similar to the observations in the basic $pn \to d \pi^0\pi^0$ reaction and in the $dd \to ^4$He$\pi^0\pi^0$ reaction, the data reveal a correlation between the ABC effect and a resonance-like energy dependence in the total cross section. Read More

2014Aug
Authors: P. Adlarson1, W. Augustyniak2, W. Bardan3, M. Bashkanov4, F. S. Bergmann5, M. Berłowski6, H. Bhatt7, M. Büscher8, H. Calén9, I. Ciepał10, H. Clement11, D. Coderre12, E. Czerwiński13, K. Demmich14, E. Doroshkevich15, R. Engels16, A. Erven17, W. Erven18, W. Eyrich19, P. Fedorets20, K. Föhl21, K. Fransson22, F. Goldenbaum23, P. Goslawski24, A. Goswami25, K. Grigoryev26, C. --O. Gullström27, F. Hauenstein28, L. Heijkenskjöld29, V. Hejny30, M. Hodana31, B. Höistad32, N. Hüsken33, A. Jany34, B. R. Jany35, L. Jarczyk36, T. Johansson37, B. Kamys38, G. Kemmerling39, F. A. Khan40, A. Khoukaz41, D. A. Kirillov42, S. Kistryn43, H. Kleines44, B. Kłos45, M. Krapp46, W. Krzemień47, P. Kulessa48, A. Kupść49, K. Lalwani50, D. Lersch51, B. Lorentz52, A. Magiera53, R. Maier54, P. Marciniewski55, B. Mariański56, M. Mikirtychiants57, H. --P. Morsch58, P. Moskal59, H. Ohm60, I. Ozerianska61, E. Perez del Rio62, N. M. Piskunov63, P. Podkopał64, D. Prasuhn65, A. Pricking66, D. Pszczel67, K. Pysz68, A. Pyszniak69, C. F. Redmer70, J. Ritman71, A. Roy72, Z. Rudy73, S. Sawant74, S. Schadmand75, T. Sefzick76, V. Serdyuk77, R. Siudak78, T. Skorodko79, M. Skurzok80, J. Smyrski81, V. Sopov82, R. Stassen83, J. Stepaniak84, E. Stephan85, G. Sterzenbach86, H. Stockhorst87, H. Ströher88, A. Szczurek89, A. Täschner90, A. Trzciński91, R. Varma92, G. J. Wagner93, M. Wolke94, A. Wrońska95, P. Wüstner96, P. Wurm97, A. Yamamoto98, L. Yurev99, J. Zabierowski100, M. J. Zieliński101, A. Zink102, J. Złomańczuk103, P. {Ż}uprański104, M. {Ż}urek105, R. L. Workman106, W. J. Briscoe107, I. I. Strakovsky108
Affiliations: 1WASA-at-COSY Collaboration, 2WASA-at-COSY Collaboration, 3WASA-at-COSY Collaboration, 4WASA-at-COSY Collaboration, 5WASA-at-COSY Collaboration, 6WASA-at-COSY Collaboration, 7WASA-at-COSY Collaboration, 8WASA-at-COSY Collaboration, 9WASA-at-COSY Collaboration, 10WASA-at-COSY Collaboration, 11WASA-at-COSY Collaboration, 12WASA-at-COSY Collaboration, 13WASA-at-COSY Collaboration, 14WASA-at-COSY Collaboration, 15WASA-at-COSY Collaboration, 16WASA-at-COSY Collaboration, 17WASA-at-COSY Collaboration, 18WASA-at-COSY Collaboration, 19WASA-at-COSY Collaboration, 20WASA-at-COSY Collaboration, 21WASA-at-COSY Collaboration, 22WASA-at-COSY Collaboration, 23WASA-at-COSY Collaboration, 24WASA-at-COSY Collaboration, 25WASA-at-COSY Collaboration, 26WASA-at-COSY Collaboration, 27WASA-at-COSY Collaboration, 28WASA-at-COSY Collaboration, 29WASA-at-COSY Collaboration, 30WASA-at-COSY Collaboration, 31WASA-at-COSY Collaboration, 32WASA-at-COSY Collaboration, 33WASA-at-COSY Collaboration, 34WASA-at-COSY Collaboration, 35WASA-at-COSY Collaboration, 36WASA-at-COSY Collaboration, 37WASA-at-COSY Collaboration, 38WASA-at-COSY Collaboration, 39WASA-at-COSY Collaboration, 40WASA-at-COSY Collaboration, 41WASA-at-COSY Collaboration, 42WASA-at-COSY Collaboration, 43WASA-at-COSY Collaboration, 44WASA-at-COSY Collaboration, 45WASA-at-COSY Collaboration, 46WASA-at-COSY Collaboration, 47WASA-at-COSY Collaboration, 48WASA-at-COSY Collaboration, 49WASA-at-COSY Collaboration, 50WASA-at-COSY Collaboration, 51WASA-at-COSY Collaboration, 52WASA-at-COSY Collaboration, 53WASA-at-COSY Collaboration, 54WASA-at-COSY Collaboration, 55WASA-at-COSY Collaboration, 56WASA-at-COSY Collaboration, 57WASA-at-COSY Collaboration, 58WASA-at-COSY Collaboration, 59WASA-at-COSY Collaboration, 60WASA-at-COSY Collaboration, 61WASA-at-COSY Collaboration, 62WASA-at-COSY Collaboration, 63WASA-at-COSY Collaboration, 64WASA-at-COSY Collaboration, 65WASA-at-COSY Collaboration, 66WASA-at-COSY Collaboration, 67WASA-at-COSY Collaboration, 68WASA-at-COSY Collaboration, 69WASA-at-COSY Collaboration, 70WASA-at-COSY Collaboration, 71WASA-at-COSY Collaboration, 72WASA-at-COSY Collaboration, 73WASA-at-COSY Collaboration, 74WASA-at-COSY Collaboration, 75WASA-at-COSY Collaboration, 76WASA-at-COSY Collaboration, 77WASA-at-COSY Collaboration, 78WASA-at-COSY Collaboration, 79WASA-at-COSY Collaboration, 80WASA-at-COSY Collaboration, 81WASA-at-COSY Collaboration, 82WASA-at-COSY Collaboration, 83WASA-at-COSY Collaboration, 84WASA-at-COSY Collaboration, 85WASA-at-COSY Collaboration, 86WASA-at-COSY Collaboration, 87WASA-at-COSY Collaboration, 88WASA-at-COSY Collaboration, 89WASA-at-COSY Collaboration, 90WASA-at-COSY Collaboration, 91WASA-at-COSY Collaboration, 92WASA-at-COSY Collaboration, 93WASA-at-COSY Collaboration, 94WASA-at-COSY Collaboration, 95WASA-at-COSY Collaboration, 96WASA-at-COSY Collaboration, 97WASA-at-COSY Collaboration, 98WASA-at-COSY Collaboration, 99WASA-at-COSY Collaboration, 100WASA-at-COSY Collaboration, 101WASA-at-COSY Collaboration, 102WASA-at-COSY Collaboration, 103WASA-at-COSY Collaboration, 104WASA-at-COSY Collaboration, 105WASA-at-COSY Collaboration, 106SAID Data Analysis Center, 107SAID Data Analysis Center, 108SAID Data Analysis Center

New data on quasifree polarized neutron-proton scattering, in the region of the recently observed $d^*$ resonance structure, have been obtained by exclusive and kinematically complete high-statistics measurements with WASA at COSY. This paper details the determination of the beam polarization, checks of the quasifree character of the scattering process, on all obtained $A_y$ angular distributions and on the new partial-wave analysis, which includes the new data producing a resonance pole in the $^3D_3$-$^3G_3$ coupled partial waves at ($2380\pm10 - i40\pm5$) MeV -- in accordance with the $d^*$ dibaryon resonance hypothesis. The effect of the new partial-wave solution on the description of total and differential cross section data as well as specific combinations of spin-correlation and spin-transfer observables available from COSY-ANKE measurements at $T_d$ = 2. Read More

Charge symmetry breaking (CSB) observables are a suitable experimental tool to examine effects induced by quark masses on the nuclear level. Previous high precision data from TRIUMF and IUCF are currently used to develop a consistent description of CSB within the framework of chiral perturbation theory. In this work the experimental studies on the reaction dd->4He{\pi}0 have been extended towards higher excess energies in order to provide information on the contribution of p-waves in the final state. Read More

2014Jul

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. Read More

2014Jun
Authors: The HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, S. Belostotski, N. Bianchi, H. P. Blok, A. Borissov, J. Bowles, I. Brodski, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, L. De Nardo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Düren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, R. Fabbri, A. Fantoni, L. Felawka, S. Frullani, D. Gabbert, G. Gapienko, V. Gapienko, F. Garibaldi, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Golembiovskaya, C. Hadjidakis, M. Hartig, D. Hasch, A. Hillenbrand, M. Hoek, Y. Holler, I. Hristova, Y. Imazu, A. Ivanilov, H. E. Jackson, H. S. Jo, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, N. Kobayashi, V. Korotkov, V. Kozlov, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, L. Lapikás, I. Lehmann, P. Lenisa, A. López Ruiz, W. Lorenzon, X. -G. Lu, B. -Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, Y. Mao, B. Marianski, A. Martinez de la Ossa, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, V. Muccifora, M. Murray, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W. -D. Nowak, L. L. Pappalardo, R. Perez-Benito, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, F. Sanftl, A. Schäfer, G. Schnell, K. P. Schüler, B. Seitz, T. -A. Shibata, V. Shutov, M. Stancari, M. Statera, E. Steffens, J. J. M. Steijger, J. Stewart, F. Stinzing, S. Taroian, A. Terkulov, R. Truty, A. Trzcinski, M. Tytgat, A. Vandenbroucke, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, V. Vikhrov, I. Vilardi, S. Wang, S. Yaschenko, Z. Ye, W. Yu, V. Zagrebelnyy, D. Zeiler, B. Zihlmann, P. Zupranski

The transverse polarization of $\Lambda$ 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. Read More

2014Jun

Dalitz plot distribution of the $\eta\to\pi^+\pi^-\pi^0$ decay is determined using a data sample of $1.2\cdot 10^7$ $\eta$ mesons from $pd\to ^3\textrm{He}\eta$ reaction at 1 GeV collected by the WASA detector at COSY. Read More

Exclusive and kinematically complete high-statistics measurements of quasifree polarized $\vec{n}p$ scattering have been performed in the energy region of the narrow resonance structure $d^*$ with $I(J^P) = 0(3^+)$, $M \approx$ 2380 MeV/$c^2$ and $\Gamma \approx$ 70 MeV observed recently in the double-pionic fusion channels $pn \to d\pi^0\pi^0$ and $pn \to d\pi^+\pi^-$. The experiment was carried out with the WASA detector setup at COSY having a polarized deuteron beam impinged on the hydrogen pellet target and utilizing the quasifree process $\vec{d}p \to np + p_{spectator}$. That way the $np$ analyzing power $A_y$ was measured over a large angular range. Read More

2014Feb

We present new data for angular distributions and on the cross section ratio of the p + d -> 3He + eta reaction at excess energies of Q = 48.8 MeV and Q = 59.8 MeV. Read More

2013Dec

An earlier extraction from the HERMES experiment of the polarization-averaged parton distribution of strange quarks in the nucleon has been reevaluated using final data on the multiplicities of charged kaons in semi-inclusive deep-inelastic scattering obtained with a kinematically more comprehensive method of correcting for experimental effects. General features of the distribution are confirmed, but the rise at low x is less pronounced than previously reported. Read More

2013Oct
Authors: The HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, S. Belostotski, N. Bianchi, H. P. Blok, A. Borissov, J. Bowles, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, L. De Nardo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Düren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, R. Fabbri, A. Fantoni, L. Felawka, S. Frullani, D. Gabbert, G. Gapienko, V. Gapienko, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Golembiovskaya, C. Hadjidakis, M. Hartig, D. Hasch, A. Hillenbrand, M. Hoek, Y. Holler, I. Hristova, A. Ivanilov, H. E. Jackson, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, V. Korotkov, V. Kozlov, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, L. Lapikás, I. Lehmann, P. Lenisa, A. López Ruiz, W. Lorenzon, B. -Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, Y. Mao, B. Marianski, A. Martinez de la Ossa, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, V. Muccifora, M. Murray, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W. -D. Nowak, L. L. Pappalardo, R. Perez-Benito, A. Petrosyan, M. Raithel, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, F. Sanftl, A. Schäfer, G. Schnell, B. Seitz, T. -A. Shibata, V. Shutov, M. Stancari, M. Statera, E. Steffens, J. J. M. Steijger, J. Stewart, F. Stinzing, S. Taroian, A. Terkulov, R. Truty, A. Trzcinski, M. Tytgat, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, V. Vikhrov, I. Vilardi, S. Wang, S. Yaschenko, Z. Ye, S. Yen, W. Yu, V. Zagrebelnyy, D. Zeiler, B. Zihlmann, P. Zupranski

Single-spin asymmetries were investigated in inclusive electroproduction of charged pions and kaons from transversely polarized protons at the HERMES experiment. The asymmetries were studied as a function of the azimuthal angle $\psi$ about the beam direction between the target-spin direction and the hadron production plane, the transverse hadron momentum relative to the direction of the incident beam, and the Feynman variable $x_F$. The $\sin(\psi)$ amplitudes are positive for positive pions and kaons, slightly negative for negative pions and consistent with zero for negative kaons, with particular transverse-momentum but weak $x_F$ dependences. Read More

2013Oct
Authors: The HERMES Collaboration, A. Airapetian, N. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, H. P. Blok, H. Böttcher, A. Borissov, J. Bowles, I. Brodski, V. Bryzgalov, J. Burns, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Düren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, E. Etzelmüller, R. Fabbri, S. Frullani, G. Gapienko, V. Gapienko, J. Garay García, F. Garibaldi, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Hartig, D. Hasch, Y. Holler, I. Hristova, A. Ivanilov, H. E. Jackson, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, V. Korotkov, V. Kozlov, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, L. Lapikás, I. Lehmann, P. Lenisa, W. Lorenzon, X. -G. Lu, B. -Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, Y. Mao, B. Marianski, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, V. Muccifora, M. Murray, A. Mussgiller, Y. Naryshkin, A. Nass, M. Negodaev, W. -D. Nowak, L. L. Pappalardo, R. Perez-Benito, A. Petrosyan, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, A. Schäfer, G. Schnell, B. Seitz, T. -A. Shibata, M. Stahl, M. Statera, E. Steffens, J. J. M. Steijger, J. Stewart, F. Stinzing, S. Taroian, A. Terkulov, R. Truty, A. Trzcinski, M. Tytgat, Y. Van Haarlem, C. Van Hulse, V. Vikhrov, I. Vilardi, S. Wang, S. Yaschenko, Z. Ye, S. Yen, V. Zagrebelnyy, B. Zihlmann, P. Zupranski

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. Read More

2013Jun

Exclusive measurements of the quasi-free $pn \to pp\pi^0\pi^-$ reaction have been performed by means of $pd$ collisions at $T_p$ = 1.2 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region $\sqrt s$ = (2. Read More

2013Apr

An exclusive measurement of the dd -> 3He n \pi 0 reaction was carried at a beam momentum of p = 1.2 GeV/c using the WASA-at-COSY facility. For the first time data on the total cross section as well as differential distributions were obtained. Read More

2013Apr

The presently world largest data sample of pi0 --> gamma e+e- decays containing nearly 5E5 events was collected using the WASA detector at COSY. A search for a dark photon U produced in the pi0 --> gamma U --> gamma e+e- decay from the pp-->pp\pi^0 reaction was carried out. An upper limit on the square of the U-gamma mixing strength parameter epsilon^2 of 5e-6 at 90% CL was obtained for the mass range 20 MeV Read More

2013Jan
Authors: P. Adlarson1, W. Augustyniak2, W. Bardan3, M. Bashkanov4, T. Bednarski5, F. S. Bergmann6, M. Berlowski7, H. Bhatt8, M. Buescher9, H. Calen10, H. Clement11, D. Coderre12, E. Czerwinski13, K. Demmich14, E. Doroshkevich15, R. Engels16, W. Erven17, W. Eyrich18, P. Fedorets19, K. Foehl20, K. Fransson21, F. Goldenbaum22, P. Goslawski23, A. Goswami24, K. Grigoryev25, C. -O. Gullstroem26, F. Hauenstein27, L. Heijkenskjoeld28, V. Hejny29, F. Hinterberger30, M. Hodana31, B. Hoeistad32, A. Jany33, B. R. Jany34, L. Jarczyk35, T. Johansson36, B. Kamys37, G. Kemmerling38, F. A. Khan39, A. Khoukaz40, S. Kistryn41, J. Klaja42, H. Kleines43, B. Klos44, M. Krapp45, W. Krzemien46, P. Kulessa47, A. Kupsc48, K. Lalwani49, D. Lersch50, L. Li51, B. Lorentz52, A. Magiera53, R. Maier54, P. Marciniewski55, B. Marianski56, M. Mikirtychiants57, H. -P. Morsch58, P. Moskal59, B. K. Nandi60, S. Niedzwiecki61, H. Ohm62, I. Ozerianska63, E. Perez del Rio64, P. Plucinski65, P. Podkopal66, D. Prasuhn67, A. Pricking68, D. Pszczel69, K. Pysz70, A. Pyszniak71, C. F. Redmer72, J. Ritman73, A. Roy74, Z. Rudy75, S. Sawant76, S. Schadmand77, A. Schmidt78, T. Sefzick79, V. Serdyuk80, N. Shah81, M. Siemaszko82, R. Siudak83, T. Skorodko84, M. Skurzok85, J. Smyrski86, V. Sopov87, R. Stassen88, J. Stepaniak89, E. Stephan90, G. Sterzenbach91, H. Stockhorst92, H. Stroeher93, A. Szczurek94, T. Tolba95, A. Trzcinski96, R. Varma97, P. Vlasov98, G. J. Wagner99, W. Weglorz100, M. Wolke101, A. Wronska102, P. Wuestner103, P. Wurm104, A. Yamamoto105, X. Yuan106, L. Yurev107, J. Zabierowski108, C. Zheng109, M. J. Zielinski110, W. Zipper111, J. Zlomanczuk112, P. Zupranski113, M. Zurek114
Affiliations: 1WASA-at-COSY collaboration, 2WASA-at-COSY collaboration, 3WASA-at-COSY collaboration, 4WASA-at-COSY collaboration, 5WASA-at-COSY collaboration, 6WASA-at-COSY collaboration, 7WASA-at-COSY collaboration, 8WASA-at-COSY collaboration, 9WASA-at-COSY collaboration, 10WASA-at-COSY collaboration, 11WASA-at-COSY collaboration, 12WASA-at-COSY collaboration, 13WASA-at-COSY collaboration, 14WASA-at-COSY collaboration, 15WASA-at-COSY collaboration, 16WASA-at-COSY collaboration, 17WASA-at-COSY collaboration, 18WASA-at-COSY collaboration, 19WASA-at-COSY collaboration, 20WASA-at-COSY collaboration, 21WASA-at-COSY collaboration, 22WASA-at-COSY collaboration, 23WASA-at-COSY collaboration, 24WASA-at-COSY collaboration, 25WASA-at-COSY collaboration, 26WASA-at-COSY collaboration, 27WASA-at-COSY collaboration, 28WASA-at-COSY collaboration, 29WASA-at-COSY collaboration, 30WASA-at-COSY collaboration, 31WASA-at-COSY collaboration, 32WASA-at-COSY collaboration, 33WASA-at-COSY collaboration, 34WASA-at-COSY collaboration, 35WASA-at-COSY collaboration, 36WASA-at-COSY collaboration, 37WASA-at-COSY collaboration, 38WASA-at-COSY collaboration, 39WASA-at-COSY collaboration, 40WASA-at-COSY collaboration, 41WASA-at-COSY collaboration, 42WASA-at-COSY collaboration, 43WASA-at-COSY collaboration, 44WASA-at-COSY collaboration, 45WASA-at-COSY collaboration, 46WASA-at-COSY collaboration, 47WASA-at-COSY collaboration, 48WASA-at-COSY collaboration, 49WASA-at-COSY collaboration, 50WASA-at-COSY collaboration, 51WASA-at-COSY collaboration, 52WASA-at-COSY collaboration, 53WASA-at-COSY collaboration, 54WASA-at-COSY collaboration, 55WASA-at-COSY collaboration, 56WASA-at-COSY collaboration, 57WASA-at-COSY collaboration, 58WASA-at-COSY collaboration, 59WASA-at-COSY collaboration, 60WASA-at-COSY collaboration, 61WASA-at-COSY collaboration, 62WASA-at-COSY collaboration, 63WASA-at-COSY collaboration, 64WASA-at-COSY collaboration, 65WASA-at-COSY collaboration, 66WASA-at-COSY collaboration, 67WASA-at-COSY collaboration, 68WASA-at-COSY collaboration, 69WASA-at-COSY collaboration, 70WASA-at-COSY collaboration, 71WASA-at-COSY collaboration, 72WASA-at-COSY collaboration, 73WASA-at-COSY collaboration, 74WASA-at-COSY collaboration, 75WASA-at-COSY collaboration, 76WASA-at-COSY collaboration, 77WASA-at-COSY collaboration, 78WASA-at-COSY collaboration, 79WASA-at-COSY collaboration, 80WASA-at-COSY collaboration, 81WASA-at-COSY collaboration, 82WASA-at-COSY collaboration, 83WASA-at-COSY collaboration, 84WASA-at-COSY collaboration, 85WASA-at-COSY collaboration, 86WASA-at-COSY collaboration, 87WASA-at-COSY collaboration, 88WASA-at-COSY collaboration, 89WASA-at-COSY collaboration, 90WASA-at-COSY collaboration, 91WASA-at-COSY collaboration, 92WASA-at-COSY collaboration, 93WASA-at-COSY collaboration, 94WASA-at-COSY collaboration, 95WASA-at-COSY collaboration, 96WASA-at-COSY collaboration, 97WASA-at-COSY collaboration, 98WASA-at-COSY collaboration, 99WASA-at-COSY collaboration, 100WASA-at-COSY collaboration, 101WASA-at-COSY collaboration, 102WASA-at-COSY collaboration, 103WASA-at-COSY collaboration, 104WASA-at-COSY collaboration, 105WASA-at-COSY collaboration, 106WASA-at-COSY collaboration, 107WASA-at-COSY collaboration, 108WASA-at-COSY collaboration, 109WASA-at-COSY collaboration, 110WASA-at-COSY collaboration, 111WASA-at-COSY collaboration, 112WASA-at-COSY collaboration, 113WASA-at-COSY collaboration, 114WASA-at-COSY collaboration

An exclusive measurement of the excitation function for the dd->3Heppi- reaction was performed at the Cooler Synchrotron COSY-Juelich with the WASA-at-COSY detection system. The data were taken during a slow acceleration of the beam from 2.185 GeV/c to 2. Read More

2012Dec
Authors: HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, S. Belostotski, H. P. Blok, A. Borissov, J. Bowles, I. Brodski, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, L. De Nardo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Düren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, R. Fabbri, A. Fantoni, L. Felawka, S. Frullani, D. Gabbert, G. Gapienko, V. Gapienko, F. Garibaldi, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Golembiovskaya, C. Hadjidakis, M. Hartig, D. Hasch, A. Hillenbrand, M. Hoek, Y. Holler, I. Hristova, Y. Imazu, A. Ivanilov, A. Izotov, H. E. Jackson, H. S. Jo, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, N. Kobayashi, V. Korotkov, V. Kozlov, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, L. Lapikás, I. Lehmann, P. Lenisa, A. López Ruiz, W. Lorenzon, B. -Q. Ma, D. Mahon, B. Maiheu, N. C. R. Makins, S. I. Manaenkov, L. Manfré, Y. Mao, B. Marianski, A. Martinez de la Ossa, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, M. Murray, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W. -D. Nowak, L. L. Pappalardo, R. Perez-Benito, A. Petrosyan, M. Raithel, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, F. Sanftl, A. Schäfer, G. Schnell, B. Seitz, T. -A. Shibata, V. Shutov, M. Stancari, M. Statera, E. Steffens, J. J. M. Steijger, J. Stewart, F. Stinzing, S. Taroian, A. Terkulov, R. Truty, A. Trzcinski, M. Tytgat, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, I. Vilardi, C. Vogel, S. Wang, S. Yaschenko, Z. Ye, S. Yen, W. Yu, V. Zagrebelnyy, D. Zeiler, B. Zihlmann, P. Zupranski

Multiplicities in semi-inclusive deep-inelastic scattering are presented for each charge state of \pi^\pm and K^\pm mesons. The data were collected by the HERMES experiment at the HERA storage ring using 27.6 GeV electron and positron beams incident on a hydrogen or deuterium gas target. Read More

2012Dec

Exclusive and kinematically complete high-statistics measurements of the basic double pionic fusion reactions pn -> dpi0pi0, pn -> d pi+pi- and pp -> dpi+pi0 have been carried out simultaneously over the energy region of the ABC effect using the WASA detector setup at COSY. Whereas the isoscalar reaction part given by the dpi0pi0 channel exhibits the ABC effect, i.e. Read More

2012Jun

Exclusive and kinematically complete high-statistics measurements of the double pionic fusion reaction $dd \to ^4$He$\pi^0\pi^0$ have been performed in the energy range 0.8 - 1.4 GeV covering thus the region of the ABC effect, which denotes a pronounced low-mass enhancement in the $\pi\pi$-invariant mass spectrum. Read More

2012Jun
Authors: The HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, S. Belostotski, H. P. Blok, A. Borissov, J. Bowles, I. Brodski, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, L. De Nardo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Düren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, E. Etzelmüller, R. Fabbri, A. Fantoni, L. Felawka, S. Frullani, G. Gapienko, V. Gapienko, F. Garibaldi, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Golembiovskaya, I. M. Gregor, H. Guler, M. Hartig, D. Hasch, A. Hillenbrand, M. Hoek, Y. Holler, I. Hristova, A. Ivanilov, H. E. Jackson, H. S. Jo, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, V. Korotkov, V. Kozlov, B. Krauss, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, L. Lapikás, I. Lehmann, P. Lenisa, A. López Ruiz, W. Lorenzon, S. Lu, X. Lu, B. -Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, L. Manfré, Y. Mao, B. Marianski, A. Martinez de la Ossa, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, M. Murray, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W. -D. Nowak, A. Osborne, L. L. Pappalardo, R. Perez-Benito, A. Petrosyan, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, L. Rubacek, J. Rubin, D. Ryckbosch, A. Schäfer, G. Schnell, K. P. Schüler, B. Seitz, C. Shearer, T. -A. Shibata, V. Shutov, M. Stancari, M. Statera, J. J. M. Steijger, J. Stewart, S. Taroian, A. Terkulov, R. Truty, A. Trzcinski, M. Tytgat, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, V. Vikhrov, I. Vilardi, S. Wang, S. Yaschenko, Z. Ye, S. Yen, V. Zagrebelnyy, D. Zeiler, B. Zihlmann, P. Zupranski

The beam-helicity asymmetry in exclusive electroproduction of real photons by the longitudinally polarized HERA positron beam scattering off an unpolarized hydrogen target is measured at HERMES. The asymmetry arises from deeply virtual Compton scattering and its interference with the Bethe--Heitler process. Azimuthal amplitudes of the beam-helicity asymmetry are extracted from a data sample consisting of $ep\rightarrow ep\gamma$ events with detection of all particles in the final state including the recoiling proton. Read More

2012Apr
Authors: HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, S. Belostotski, H. P. Blok, A. Borissov, J. Bowles, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, L. De Nardo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Düren, G. Elbakian, F. Ellinghaus, A. Fantoni, L. Felawka, S. Frullani, G. Gapienko, V. Gapienko, F. Garibaldi, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Golembiovskaya, C. Hadjidakis, M. Hartig, D. Hasch, A. Hillenbrand, M. Hoek, Y. Holler, I. Hristova, Y. Imazu, A. Ivanilov, H. E. Jackson, H. S. Jo, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, V. Korotkov, V. Kozlov, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, L. Lapikás, I. Lehmann, P. Lenisa, A. López Ruiz, W. Lorenzon, B. -Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, L. Manfré, Y. Mao, B. Marianski, A. Martinez de la Ossa, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, M. Murray, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W. -D. Nowak, L. L. Pappalardo, R. Perez-Benito, A. Petrosyan, M. Raithel, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, F. Sanftl, A. Schäfer, G. Schnell, K. P. Schüler, B. Seitz, T. -A. Shibata, M. Stancari, M. Statera, J. J. M. Steijger, J. Stewart, F. Stinzing, A. Terkulov, R. Truty, A. Trzcinski, M. Tytgat, A. Vandenbroucke, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, V. Vikhrov, I. Vilardi, S. Wang, S. Yaschenko, Z. Ye, S. Yen, W. Yu, V. Zagrebelnyy, D. Zeiler, B. Zihlmann, P. Zupranski

The azimuthal cos{\phi} and cos2{\phi} modulations of the distribution of hadrons produced in unpolarized semi-inclusive deep-inelastic scattering of electrons and positrons off hydrogen and deuterium targets have been measured in the HERMES experiment. For the first time these modulations were determined in a four-dimensional kinematic space for positively and negatively charged pions and kaons separately, as well as for unidentified hadrons. These azimuthal dependences are sensitive to the transverse motion and polarization of the quarks within the nucleon via, e. Read More

2012Mar
Authors: The HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, H. P. Blok, A. Borissov, J. Bowles, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, L. De Nardo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Düren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, A. Fantoni, L. Felawka, S. Frullani, D. Gabbert, G. Gapienko, V. Gapienko, F. Garibaldi, G. Gavrilov, F. Giordano, S. Gliske, M. Golembiovskaya, C. Hadjidakis, M. Hartig, D. Hasch, M. Hoek, Y. Holler, Y. Imazu, H. E. Jackson, H. S. Jo, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, N. Kobayashi, V. Korotkov, V. Kozlov, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, L. Lapikás, I. Lehmann, P. Lenisa, W. Lorenzon, B. -Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, L. Manfré, Y. Mao, B. Marianski, A. Martinez de la Ossa, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, V. Muccifora, M. Murray, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, W. -D. Nowak, L. L. Pappalardo, R. Perez-Benito, A. Petrosyan, M. Raithel, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, F. Sanftl, A. Schäfer, G. Schnell, K. P. Schüler, B. Seitz, T. -A. Shibata, V. Shutov, M. Stancari, M. Statera, E. Steffens, J. J. M. Steijger, J. Stewart, S. Taroian, A. Terkulov, R. Truty, A. Trzcinski, M. Tytgat, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, V. Vikhrov, I. Vilardi, S. Wang, S. Yaschenko, Z. Ye, S. Yen, W. Yu, V. Zagrebelnyy, D. Zeiler, B. Zihlmann, P. Zupranski

Beam-helicity and beam-charge asymmetries in the hard exclusive leptoproduction of real photons from an unpolarised hydrogen target by a 27.6 GeV lepton beam are extracted from the HERMES data set of 2006-2007 using a missing-mass event selection technique. The asymmetry amplitudes extracted from this data set are more precise than those extracted from the earlier data set of 1996-2005 previously analysed in the same manner by HERMES. Read More

This paper reports results from a study of the reaction pp->pK0\Sigma+ at beam momenta of p_{beam} = 2950, 3059, and 3200 MeV/c (excess energies of \epsilon= 126, 161, and 206 MeV). Total cross sections were determined for all energies; a set of differential cross sections (Dalitz plots; invariant mass spectra of all two-body subsystems; angular distributions of all final state particles; distributions in helicity and Jackson frames) are presented for \epsilon= 161 MeV. The total cross sections are proportional to the volume of available three-body phase-space indicating that the transition matrix element does not change significantly in this range of excess energies. Read More

2011Dec
Authors: The HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, S. Belostotski, N. Bianchi, H. P. Blok, A. Borissov, J. Bowles, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, L. De Nardo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Düren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, A. Fantoni, L. Felawka, S. Frullani, D. Gabbert, G. Gapienko, V. Gapienko, F. Garibaldi, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Golembiovskaya, C. Hadjidakis, M. Hartig, D. Hasch, A. Hillenbrand, M. Hoek, Y. Holler, I. Hristova, Y. Imazu, A. Ivanilov, H. E. Jackson, H. S. Jo, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, V. Korotkov, V. Kozlov, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, L. Lapikás, I. Lehmann, P. Lenisa, A. López Ruiz, W. Lorenzon, B. -Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, L. Manfré, Y. Mao, B. Marianski, A. Martinez de la Ossa, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, V. Muccifora, M. Murray, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W. -D. Nowak, L. L. Pappalardo, R. Perez-Benito, A. Petrosyan, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, F. Sanftl, A. Schäfer, G. Schnell, K. P. Schüler, B. Seitz, T. -A. Shibata, V. Shutov, M. Stancari, M. Statera, E. Steffens, J. J. M. Steijger, J. Stewart, F. Stinzing, S. Taroian, A. Terkulov, R. Truty, A. Trzcinski, M. Tytgat, A. Vandenbroucke, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, V. Vikhrov, I. Vilardi, S. Wang, S. Yaschenko, Z. Ye, S. Yen, V. Zagrebelnyy, D. Zeiler, B. Zihlmann, P. Zupranski

A measurement of the virtual-photon asymmetry A_2(x,Q^2) and of the spin-structure function g_2(x,Q^2) of the proton are presented for the kinematic range 0.004 < x < 0.9 and 0. Read More

2011Jul
Authors: P. Adlarson, C. Adolph, W. Augustyniak, W. Bardan, M. Bashkanov, T. Bednarski, F. S. Bergmann, M. Berłowski, H. Bhatt, K. -T. Brinkmann, M. Büscher, H. Calén, H. Clement, D. Coderre, E. Czerwiński, E. Doroshkevich, R. Engels, W. Erven, W. Eyrich, P. Fedorets, K. Föhl, K. Fransson, F. Goldenbaum, P. Goslawski, K. Grigoryev, C. -O. Gullström, C. Hanhart, L. Heijkenskjöld, J. Heimlich, V. Hejny, F. Hinterberger, M. Hodana, B. Höistad, M. Jacewicz, A. Jany, B. R. Jany, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, O. Khakimova, A. Khoukaz, S. Kistryn, J. Klaja, H. Kleines, B. Kłos, F. Kren, W. Krzemień, P. Kulessa, A. Kupść, K. Lalwani, S. Leupold, B. Lorentz, A. Magiera, R. Maier, B. Mariański, P. Marciniewski, U. -G. Meißner, M. Mikirtychiants, H. -P. Morsch, P. Moskal, B. K. Nandi, S. Niedźwiecki, H. Ohm, A. Passfeld, C. Pauly, E. Perez del Rio, T. Petri, Y. Petukhov, N. Piskunov, P. Pluciński, P. Podkopał, A. Povtoreyko, D. Prasuhn, A. Pricking, K. Pysz, A. Pyszniak, T. Rausmann, C. F. Redmer, J. Ritman, A. Roy, Z. Rudy, S. Sawant, S. Schadmand, A. Schmidt, T. Sefzick, V. Serdyuk, N. Shah, M. Siemaszko, R. Siudak, T. Skorodko, M. Skurzok, J. Smyrski, V. Sopov, R. Stassen, J. Stepaniak, G. Sterzenbach, H. Stockhorst, F. Stollenwerk, A. Szczurek, A. Täschner, C. Terschlüsen, T. Tolba, A. Trzciński, R. Varma, P. Vlasov, G. J. Wagner, W. Węglorz, A. Winnemöller, A. Wirzba, M. Wolke, A. Wrońska, P. Wüstner, P. Wurm, X. Yuan, L. Yurev, J. Zabierowski, C. Zheng, M. J. Zieliński, W. Zipper, J. Złomańczuk, P. Żuprański

An exclusive measurement of the decay eta --> pi+ pi- gamma has been performed at the WASA facility at COSY. The eta mesons were produced in the fusion reaction pd --> 3He X at a proton beam momentum of 1.7 GeV/c. Read More

2011Jul
Authors: HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, S. Belostotski, N. Bianchi, H. P. Blok, A. Borissov, J. Bowles, I. Brodski, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, L. De Nardo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Düren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, R. Fabbri, A. Fantoni, L. Felawka, S. Frullani, G. Gapienko, V. Gapienko, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Golembiovskaya, L. Grigoryan, C. Hadjidakis, M. Hartig, D. Hasch, A. Hillenbrand, M. Hoek, Y. Holler, I. Hristova, Y. Imazu, A. Ivanilov, H. E. Jackson, H. S. Jo, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, N. Kobayashi, V. Korotkov, V. Kozlov, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, L. Lapikás, I. Lehmann, P. Lenisa, A. López Ruiz, W. Lorenzon, X. -G. Lu, X. -R. Lu, B. -Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, L. Manfré, Y. Mao, B. Marianski, A. Martinez de la Ossa, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, V. Muccifora, M. Murray, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W. -D. Nowak, L. L. Pappalardo, R. Perez-Benito, A. Petrosyan, M. Raithel, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, F. Sanftl, A. Schäfer, G. Schnell, B. Seitz, T. -A. Shibata, V. Shutov, M. Stancari, M. Statera, E. Steffens, J. J. M. Steijger, J. Stewart, F. Stinzing, S. Taroian, R. Truty, A. Trzcinski, M. Tytgat, A. Vandenbroucke, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, V. Vikhrov, I. Vilardi, C. Vogel, S. Wang, S. Yaschenko, Z. Ye, S. Yen, W. Yu, V. Zagrebelnyy, D. Zeiler, B. Zihlmann, P. Zupranski

Hadron multiplicities in semi-inclusive deep-inelastic scattering were measured on neon, krypton and xenon targets relative to deuterium at an electron(positron)-beam energy of 27.6 GeV at HERMES. These ratios were determined as a function of the virtual-photon energy nu, its virtuality Q2, the fractional hadron energy z and the transverse hadron momentum with respect to the virtual-photon direction pt . Read More

2011Jul

The reaction pp->pppi0pi0 has been investigated at a beam energy of 1.4 GeV using the WASA-at-COSY facility. The total cross section is found to be (324 +- 21_systematic +- 58_normalization) mub. Read More

2011Jun
Authors: The HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, S. Belostotski, N. Bianchi, H. P. Blok, A. Borissov, J. Bowles, I. Brodski, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, L. De Nardo, E. De Sanctis, P. Di Nezza, M. Dueren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, R. Fabbri, A. Fantoni, L. Felawka, S. Frullani, D. Gabbert, G. Gapienko, V. Gapienko, F. Garibaldi, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Golembiovskaya, M. Hartig, D. Hasch, M. Hoek, Y. Holler, I. Hristova, Y. Imazu, A. Ivanilov, H. E. Jackson, H. S. Jo, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, V. Korotkov, V. Kozlov, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, L. Lapikas, I. Lehmann, P. Lenisa, A. Lopez Ruiz, W. Lorenzon, X. -G. Lu, X. -R. Lu, B. -Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, L. Manfre, Y. Mao, B. Marianski A. Martinez de la Ossa, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, M. Murray, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W. -D. Nowak, L. L. Pappalardo, R. Perez-Benito, M. Raithel, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, A. Schaefer, G. Schnell, K. P. Schueler, B. Seitz, T. -A. Shibata, V. Shutov, M. Stancari, M. Statera, E. Steffens, J. J. M. Steijger, F. Stinzing, S. Taroian, A. Terkulov, R. Truty, A. Trzcinski, M. Tytgat, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, V. Vikhrov, I. Vilardi, S. Wang, S. Yaschenko, Z. Ye, S. Yen, V. Zagrebelnyy, D. Zeiler, B. Zihlmann, P. Zupranski

Double-spin asymmetries in exclusive electroproduction of real photons from a transversely polarized hydrogen target are measured with respect to the product of target polarization with beam helicity and beam charge, and with respect to the product of target polarization with beam helicity alone. The asymmetries arise from the deeply virtual Compton scattering process and its interference with the Bethe--Heitler process. They are related to the real part of the same combination of Compton form factors as that determining the previously published transverse target single-spin asymmetries through the imaginary part. Read More

2011Apr
Authors: P. Adlarson, C. Adolph, W. Augustyniak, V. Baru, M. Bashkanov, F. S. Bergmann, M. Berlowski, H. Bhatt, K. -T. Brinkmann, M. Buescher, H. Calen, H. Clement, D. Coderre, E. Czerwinski, E. Doroshkevich, C. Ekstrom, R. Engels, W. Erven, W. Eyrich, P. Fedorets, K. Foehl, K. Fransson, F. Goldenbaum, P. Goslawski, K. Grigoryev, V. Grishina, C. -O. Gullstrom, J. Hampe, C. Hanhart, L. Heijkenskj, V. Hejny, F. Hinterberger, M. Hodana, B. Hoistad, M. Jacewicz, M. Janusz, A. Jany, B. R. Jany, L. Jarczyk, J. Jaus, T. Johansson, B. Kamys, G. Kemmerling, O. Khakimova, A. Khoukaz, S. Kistryn, J. Klaja, H. Kleines, B. Klos, F. Kren, W. Krzemien, P. Kulessa, S. Kullander, A. Kupsc, K. Lalwani, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, M. Mikirtychiants, P. Moskal, H. -P. Morsch, B. K. Nandi, H. Ohm, A. Passfeld, C. Pauly, E. Perez del Rio, Y. Petukhov, N. Piskunov, P. Plucinski, P. Podkopal, A. Povtoreyko, D. Prasuhn, A. Pricking, K. Pysz, T. Rausmann, C. F. Redmer, J. Ritman, A. Roy, R. J. M. Y. Ruber, Z. Rudy, S. Schadmand, A. Schmidt, W. Schroeder, T. Sefzick, V. Serdyuk, N. Shah, M. Siemaszko, R. Siudak, T. Skorodko, M. Skurzok, J. Smyrski, V. Sopov, R. Stassen, J. Stepaniak, G. Sterzenbach, H. Stockhorst, H. Stroeher, A. Szczurek, A. Taeschner, T. Tolba, A. Trzcinski, R. Varma, P. Vlasov, G. J. Wagner, W. Weglorz, A. Winnemoeller, A. Wirzba, M. Wolke, A. Wronska, P. Wuestner, P. Wurm, L. Yurev, J. Zabierowski, M. J. Zielinski, W. Zipper, J. Zlomanczuk, P. Zupranski

We report on a high-statistics measurement of the basic double pionic fusion reaction $pn \to d\pi^0\pi^0$ over the energy region of the so-called ABC effect, a pronounced low-mass enhancement in the $\pi\pi$-invariant mass spectrum. The measurements were performed with the WASA detector setup at COSY. The data reveal the ABC effect to be associated with a Lorentzian shaped energy dependence in the integral cross section. Read More

2011Mar
Authors: The HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, S. Belostotski, N. Bianchi, H. P. Blok, A. Borissov, J. Bowles, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, L. De Nardo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Dueren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, R. Fabbri, A. Fantoni, L. Felawka, S. Frullani, D. Gabbert, G. Gapienko, V. Gapienko, F. Garibaldi, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Golembiovskaya, C. Hadjidakis, M. Hartig, D. Hasch, G. Hill, A. Hillenbrand, M. Hoek, Y. Holler, I. Hristova, Y. Imazu, A. Ivanilov, H. E. Jackson, H. S. Jo, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, V. Korotkov, V. Kozlov, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, R. Lamb, L. Lapikas, I. Lehmann, P. Lenisa, L. A. Linden-Levy, A. Lopez Ruiz, W. Lorenzon, X. -G. Lu, X. -R. Lu, B. -Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, L. Manfre, Y. Mao, B. Marianski, A. Martinez de la Ossa, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, V. Muccifora, M. Murray, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W. -D. Nowak, L. L. Pappalardo, R. Perez-Benito, N. Pickert, M. Raithel, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, F. Sanftl, A. Schaefer, G. Schnell, K. P. Schueler, B. Seitz, T. -A. Shibata, V. Shutov, M. Stancari, M. Statera, E. Steffens, J. J. M. Steijger, H. Stenzel, J. Stewart, F. Stinzing, S. Taroian, A. Trzcinski, M. Tytgat, A. Vandenbroucke, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, V. Vikhrov, I. Vilardi, C. Vogel, S. Wang, S. Yaschenko, H. Ye, Z. Ye, S. Yen, W. Yu, D. Zeiler, B. Zihlmann, P. Zupranski

Results of inclusive measurements of inelastic electron and positron scattering from unpolarized protons and deuterons at the HERMES experiment are presented. The structure functions $F_2^p$ and $F_2^d$ are determined using a parameterization of existing data for the longitudinal-to-transverse virtual-photon absorption cross-section ratio. The HERMES results provide data in the ranges $0. Read More

2010Dec
Authors: The HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, S. Belostotski, N. Bianchi, H. P. Blok, A. Borissov, J. Bowles, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, L. De Nardo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Dueren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, R. Fabbri, A. Fantoni, L. Felawka, S. Frullani, D. Gabbert, G. Gapienko, V. Gapienko, F. Garibaldi, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Golembiovskaya, C. Hadjidakis, M. Hartig, D. Hasch, G. Hill, A. Hillenbrand, M. Hoek, Y. Holler, I. Hristova, Y. Imazu, A. Ivanilov, H. E. Jackson, H. S. Jo, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, N. Kobayashi, V. Korotkov, V. Kozlov, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, R. Lamb, L. Lapikas, I. Lehmann, P. Lenisa, L. A. Linden-Levy, A. Lopez Ruiz, W. Lorenzon, X. -G. Lu, X. -R. Lu, B. -Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, L. Manfre, Y. Mao, B. Marianski, A. Martinez de la Ossa, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, V. Muccifora, M. Murray, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W. -D. Nowak, L. L. Pappalardo, R. Perez-Benito, N. Pickert, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, F. Sanftl, A. Schaefer, G. Schnell, K. P. Schueler, B. Seitz, T. -A. Shibata, V. Shutov, M. Stancari, M. Statera, E. Steffens, J. J. M. Steijger, F. Stinzing, S. Taroian, A. Terkulov, A. Trzcinski, M. Tytgat, A. Vandenbroucke, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, V. Vikhrov, I. Vilardi, S. Wang, S. Yaschenko, S. Yen, W. Yu, B. Zihlmann, P. Zupranski

Exclusive rho^0-meson electroproduction is studied in the HERMES experiment, using a 27.6 GeV longitudinally polarized electron/positron beam and unpolarized hydrogen and deuterium targets in the kinematic region 0.5 GeV^2 < Q^2 < 7. Read More

This paper reports results on simultaneous measurements of the reaction channels pp -> pK+\Lambda and pp -> pK+\Sigma^0 at excess energies of 204, 239, and 284 MeV (\Lambda) and 127, 162, and 207 MeV (\Sigma^0). Total and differential cross sections are given for both reactions. It is concluded from the measured total cross sections that the high energy limit of the cross section ratio is almost reached at an excess energy of only about 200 MeV. Read More

2010Aug
Authors: The HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, S. Belostotski, N. Bianchi, H. P. Blok, A. Borissov, J. Bowles, I. Brodski, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, L. De Nardo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Dueren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, A. Fantoni, L. Felawka, S. Frullani, D. Gabbert, G. Gapienko, V. Gapienko, F. Garibaldi, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Golembiovskaya, C. Hadjidakis, M. Hartig, D. Hasch, G. Hill, A. Hillenbrand, M. Hoek, Y. Holler, I. Hristova, Y. Imazu, A. Ivanilov, H. E. Jackson, A. Jgoun, H. S. Jo, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, N. Kobayashi, V. Korotkov, V. Kozlov, B. Krauss, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, R. Lamb, L. Lapikas, I. Lehmann, P. Lenisa, L. A. Linden-Levy, A. Lopez Ruiz, W. Lorenzon, X. -G. Lu, X. -R. Lu, B. -Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, L. Manfre, Y. Mao, B. Marianski, A. Martinez de la Ossa, H. Marukyan, C. A. Miller, A. Movsisyan, V. Muccifora, M. Murray, D. Mueller, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W. -D. Nowak, L. L. Pappalardo, R. Perez-Benito, N. Pickert, M. Raithel, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, F. Sanftl, A. Schaefer, G. Schnell, K. P. Schueler, B. Seitz, T. -A. Shibata, V. Shutov, M. Stancari, M. Statera, E. Steffens, J. J. M. Steijger, H. Stenzel, J. Stewart, F. Stinzing, S. Taroian, A. Terkulov, A. Trzcinski, M. Tytgat, A. Vandenbroucke, P. B. Van der Nat, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, V. Vikhrov, I. Vilardi, C. Vogel, S. Wang, S. Yaschenko, Z. Ye, S. Yen, W. Yu, D. Zeiler, B. Zihlmann, P. Zupranski

Azimuthal asymmetries in exclusive electroproduction of a real photon from a longitudinally polarized deuterium target are measured with respect to target polarization alone and with respect to target polarization combined with beam helicity and/or beam charge. The asymmetries appear in the distribution of the real photons in the azimuthal angle $\phi$ around the virtual photon direction, relative to the lepton scattering plane. The asymmetries arise from the deeply virtual Compton scattering process and its interference with the Bethe-Heitler process. Read More

2010Jun
Authors: HERMES collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, A. Bacchetta, S. Belostotski, N. Bianchi, H. P. Blok, A. Borissov, J. Bowles, I. Brodski, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, L. De Nardo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Dueren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, U. Elschenbroich, R. Fabbri, A. Fantoni, L. Felawka, S. Frullani, D. Gabbert, G. Gapienko, V. Gapienko, F. Garibaldi, V. Gharibyan, F. Giordano, S. Gliske, M. Golembiovskaya, C. Hadjidakis, M. Hartig, D. Hasch, G. Hill, A. Hillenbrand, M. Hoek, Y. Holler, I. Hristova, Y. Imazu, A. Ivanilov, A. Izotov, H. E. Jackson, H. S. Jo, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, N. Kobayashi, V. Korotkov, V. Kozlov, P. Kravchenko, L. Lagamba, R. Lamb, L. Lapikas, I. Lehmann, P. Lenisa, L. A. Linden-Levy, A. Lopez Ruiz, W. Lorenzon, X. -G. Lu, X. -R. Lu, B. -Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, L. Manfre, Y. Mao, B. Marianski, A. Martinez de la Ossa, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, M. Murray, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W. -D. Nowak, L. L. Pappalardo, R. Perez-Benito, N. Pickert, M. Raithel, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, F. Sanftl, A. Schaefer, G. Schnell, B. Seitz, T. -A. Shibata, V. Shutov, M. Stancari, M. Statera, E. Steffens, J. J. M. Steijger, H. Stenzel, J. Stewart, F. Stinzing, S. Taroian, A. Terkulov, A. Trzcinski, M. Tytgat, P. B. van der Nat, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, V. Vikhrov, I. Vilardi, C. Vogel, S. Wang, S. Yaschenko, H. Ye, Z. Ye, S. Yen, W. Yu, D. Zeiler, B. Zihlmann, P. Zupranski

Single-spin asymmetries for pions and charged kaons are measured in semi-inclusive deep-inelastic scattering of positrons and electrons off a transversely nuclear-polarized hydrogen target. The dependence of the cross section on the azimuthal angles of the target polarization (phi_S)and the produced hadron (phi) is found to have a substantial sin(phi+phi_S) modulation for the production of pi+, pi- and K+. This Fourier component can be interpreted in terms of non-zero transversity distribution functions and non-zero favored and disfavored Collins fragmentation functions with opposite sign. Read More

2010Apr
Authors: The HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, B. Ball, S. Belostotski, N. Bianchi, H. P. Blok, H. Boettcher, A. Borissov, J. Bowles, I. Brodski, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, L. De Nardo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Dueren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, R. Fabbri, A. Fantoni, L. Felawka, S. Frullani, D. Gabbert, G. Gapienko, V. Gapienko, F. Garibaldi, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Golembiovskaya, C. Hadjidakis, M. Hartig, D. Hasch, G. Hill, A. Hillenbrand, M. Hoek, Y. Holler, I. Hristova, Y. Imazu, A. Ivanilov, A. Izotov, H. E. Jackson, H. S. Jo, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, N. Kobayashi, V. Korotkov, V. Kozlov, P. Kravchenko, V. G. Krivokhijne, L. Lagamba, R. Lamb, L. Lapikas, I. Lehmann, P. Lenisa, L. A. Linden-Levy, A. Lopez~Ruiz, W. Lorenzon, X. -G. Lu, X. -R. Lu, B. -Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, L. Manfre, Y. Mao, B. Marianski, A. Martinez de la Ossa, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, V. Muccifora, M. Murray, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W. -D. Nowak, L. L. Pappalardo, R. Perez-Benito, N. Pickert, M. Raithel, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, F. Sanftl, A. Schaefer, G. Schnell, K. P. Schueler, B. Seitz, T. -A. Shibata, V. Shutov, M. Stancari, M. Statera, E. Steffens, J. J. M. Steijger, H. Stenzel, J. Stewart, F. Stinzing, S. Taroian, A. Terkulov, A. Trzcinski, M. Tytgat, A. Vandenbroucke, P. B. van der Nat,