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1. Measurement of parton distributions of strange quarks in the nucleon from charged-kaon production in deep-inelastic scattering on the deuteron

Author

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

Subjects
Quark, Particle physics, Strange quark, Nuclear and High Energy Physics, Nuclear Theory, FOS: Physical sciences, Parton, 01 natural sciences, NO, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), 13.60.-r, 13.88.+e, 14.20.Dh, 14.65.-q, 0103 physical sciences, ddc:530, SDG 14 - Life Below Water, 010306 general physics, Nuclear Experiment, Physics, 010308 nuclear & particles physics, Scattering, Deep inelastic scattering, Helicity, Strange matter, Physics and Astronomy, High Energy Physics::Experiment, Nucleon
Abstract

The momentum and helicity density distributions of the strange quark sea in the nucleon are obtained in leading order from charged-kaon production in deep-inelastic scattering on the deuteron. The distributions are extracted from spin-averaged K+/- multiplicities, and from K+/- and inclusive double-spin asymmetries for scattering of polarized positrons by a polarized deuterium target. The shape of the momentum distribution is softer than that of the average of the ubar and dbar quarks. In the region of measurement 0.02 < x < 0.6 and Q^2 > 1.0 GeV^2, the helicity distribution is zero within experimental uncertainties., 5 pages, 5 figures, 1 table; text slightly expanded, 10 references added

Published
2008
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2. O16(e,e′p) reaction at large missing energy

Author

W.H.A. Hesselink, Jan Ryckebusch, R. Starink, Franco Garibaldi, R. De Leo, Salvatore Frullani, G. M. Urciuoli, C. J. G. Onderwater, L. Lapikás, Evaristo Cisbani, E. Jans, David Groep, Mauro Iodice, and Roberto Perrino

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Missing energy, Proton, Nuclear Theory, Hadron, Momentum transfer, Baryon, Nuclear physics, Proton emission, Atomic physics, Nuclear Experiment, Nucleon
Abstract

We investigate the origin of the strength at large missing energies in electron-induced proton knockout reactions. For that purpose the reaction O16(e,ep) was studied at a central value ! = 215 MeV of the energy transfer, and two values of the momentum transfer: q = 300,400 MeV/c, corresponding to the "dip region". Differential cross sections were determined in a large range of missing energy (Em=0-140 MeV) and proton emission angle (pq=0-110 ◦ ), and compared to predictions of a model that includes nucleon-nucleon short-range correlations and two-body currents. It is observed that, in the kinematic domain covered by this experiment, the largest contribution to the cross section stems from two-body currents, while short-range correlations contribute a significant fraction.

Published
2007

3. Hard exclusive electroproduction of π+π− pairs

Author

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

Subjects
Physics, HERMES experiment, Nuclear and High Energy Physics, Particle physics, Meson, Isovector, 010308 nuclear & particles physics, Isoscalar, Nuclear Theory, Parton, 01 natural sciences, Helicity, Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, Invariant mass, Nuclear Experiment, 010306 general physics
Abstract

Hard exclusive electroproduction of π + π − pairs off hydrogen and deuterium targets has been studied by the HERMES experiment at DESY. Legendre moments 〈 P 1 〉 and 〈 P 3 〉 of the angular distributions of π + mesons in the center-of-mass frame of the pair have been measured for the first time. Their dependence on the π + π − invariant mass can be understood as being due to the interference between relative P -wave (isovector) and S -, D -wave (isoscalar) states of the two pions. The increase in magnitude of 〈 P 1 〉 as Bjorken x increases is interpreted in the framework of generalized parton distributions as an enhancement of flavour non-singlet q q ¯ exchange for larger values of x , which leads to a sizable admixture of isoscalar and isovector pion pairs. In addition, the interference between P -wave and D -wave states separately for transverse and longitudinal pion pairs has been studied. The data indicate that in the f 2 ( 1270 ) region at 〈 Q 2 〉 = 3 GeV 2 higher-twist effects can be as large as the leading-twist longitudinal component.

Published
2004

4. Probing short-range correlations in 3He and 16O using the reaction (e, e′pp)

Author

W.H.A. Hesselink, R. Starink, D.L. Groep, and E. Jans

Subjects
Physics, Nuclear and High Energy Physics, Proton emission, Atomic physics, Ground state
Abstract

Short-range correlations in 3 He and 16 O have been investigated using the reaction ( e , e ′ pp ). Data were taken at various values of the transferred four-momentum ( w , q ), and proton emission angles. The cross sections, measured for the reaction 3 He( e , e ′ pp ) n at small values of p m , are well reproduced by the results of continuum Faddeev calculations. However, at larger values of p m , serious discrepancies are observed between the experimental and theoretical cross sections. Evidence for short-range-correlations in 16 O has been obtained from the reaction 16 O( e , e ′ pp ), leading to the ground state in 14 C. The cross sections for this transition, measured as a function of p m at three values of w , are well reproduced by two parameter-free microscopic calculations. The calculations show that the reaction is dominated by knockout of protons in a 1 S 0 state, and driven by short-range correlations.

Published
2000

5. Evidence for short-range correlations in O-16

Author

J. A. Templon, M. F. van Batenburg, Roberto Perrino, C. J. G. Onderwater, L. Lapikás, W. H. Dickhoff, Evaristo Cisbani, W.H.A. Hesselink, E. Jans, R. Starink, M.F.M. Steenbakkers, David Groep, P. Heimberg, M. Iodice, Salvatore Frullani, Jan Ryckebusch, Franco Garibaldi, Franco Davide Pacati, G. M. Urciuoli, Carlotta Giusti, R. De Leo, Larry Weinstein, and (Astro)-Particles Physics

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Missing energy, Proton, 010308 nuclear & particles physics, Knockout, Function (mathematics), State (functional analysis), 7. Clean energy, 01 natural sciences, Nuclei, Momentum, 0103 physical sciences, Atomic physics, 010306 general physics, Ground state
Abstract

The reaction O-16(e,e'pp)C-14 has been investigated at three values of the transferred energy omega. The differential cross sections were determined as a function of the missing energy and the missing momentum. Evidence for short-range correlations in O-16 has been obtained from the transition to the ground state of C-14. The cross sections for this transition are well reproduced by two independent parameter-free microscopic calculations. The results of both calculations show that the reaction is dominated by knockout of a proton pair in a S-1(0) state, driven by short-range-correlations. (C) 2000 Published by Elsevier Science B.V. All rights reserved.

Published
2000

6. Proton detection with large-acceptance scintillator detection systems in electron-scattering environments

Author

R. Starink, W.J. Kasdorp, M. van Beuzekom, R.F. van Wijk, E. Kwakkel, E. Jans, H.J Sturris, Jan Visschers, Nasser Kalantar-Nayestanaki, C. J. G. Onderwater, J Kos, J. J. M. Steijger, David Groep, A Poelman, F. A. Mul, Antonio Pellegrino, A.N.M. Zwart, W.H.A. Hesselink, E.E van den Born, T Ploegmakers, H.Z. Peek, J. J. van Leeuwe, J. A. Templon, and M.N. Kruszynska

Subjects
Physics, Nuclear and High Energy Physics, Photomultiplier, Proton, Physics::Instrumentation and Detectors, business.industry, Detector, Scintillator, Nuclear magnetic resonance, Optics, Proton emission, Nucleon, business, Instrumentation, Electron scattering, Energy (signal processing)
Abstract

Two highly segmented plastic-scintillator arrays have been developed for proton detection in electron scattering experiments. The detectors subtend solid angles of 225 and 550 msr and cover energy ranges of 50-225 and 25-165 MeV, respectively. The charge and arrival time of each photomultiplier signal are digitized by flash ADCs and temporarily stored in a dual-port memory. The readout parameters are computer controlled, tuned, and monitored. These detectors have been employed in (e, e'p) and (e, e'pp) experiments for proton emission angles greater than 30 degrees and for luminosities up to 10(36) nucleons cm(-2) s(-1). The singles counting rates in the scintillator elements of the first layers were about 0.5 x 10(6) particles s(-1) and the trigger rate 1 MHz. The measured resolution in the excitation energy and timing spectra are 2.7% and 0.7 ns, respectively. (C) 1999 Elsevier Science B.V. All rights reserved.

Published
1999

7. Electron-induced two-proton knockout from 3He

Author

Jacek Golak, G.M. Urciuli, Hiroyuki Kamada, Salvatore Frullani, R. Starink, M.F.M. Steenbakkers, W. Glöckle, Evaristo Cisbani, R. De Leo, R. Perrino, David Groep, Larry Weinstein, E. Jans, Franco Garibaldi, M. Iodice, A. Scott, G.J. Lolos, L. Lapikás, D. Boersma, W.H.A. Hesselink, H. Witała, Th. S. Bauer, D. G. Ireland, P. Heimberg, H. P. Blok, H. de Vries, and M. F. van Batenburg

Subjects
Cross section (geometry), Physics, Coupling (electronics), Nuclear and High Energy Physics, Meson, Proton, Nuclear Theory, Virtual particle, Electron, Nuclear Experiment, Nucleon, Molecular physics
Abstract

Electron-induced two-nucleon knockout reactions at intermediate electron energies are driven both by one-body currents (coupling of the virtual photon to correlated nucleon pairs) and two-body currents (intermediate Δ-excitation and meson exchange currents (MEC)). In addition, final state interactions (FSI) contribute to the cross section. Recent experiments [1] have shown that the 160(e, e’pp)14C reaction is dominated by the direct knockout of strongly correlated proton pairs via one-body currents.

Published
1999

8. Signatures for Short-Range Correlations inO16Observed in the ReactionO16(e,e′pp)C14

Author

R. Starink, M.F.M. Steenbakkers, Salvatore Frullani, F. Garibaldi, J. J. M. Steijger, E. Jans, C. Kormanyos, G. M. Urciuoli, W.J.W. Geurts, H.W. Willering, W.H.A. Hesselink, Herbert Müther, David Groep, Carlotta Giusti, C. J. G. Onderwater, Franco Davide Pacati, D. Boersma, R. De Leo, M. A. van Uden, G. van der Steenhoven, W. H. Dickhoff, Nasser Kalantar-Nayestanaki, M. Iodice, A. Misiejuk, R. Perrino, K. Allaart, L. Lapikás, Larry Weinstein, W.J. Kasdorp, E.C. Aschenauer, E. Cisbani, Antonio Pellegrino, Th. S. Bauer, and J. J. van Leeuwe

Subjects
Physics, Range (particle radiation), Momentum (technical analysis), Proton, 010308 nuclear & particles physics, Momentum transfer, General Physics and Astronomy, 01 natural sciences, Omega, medicine.anatomical_structure, Excited state, 0103 physical sciences, medicine, Atomic physics, Nuclear Experiment, 010306 general physics, Ground state, Nucleus
Abstract

The reaction O-16(e,e'pp)C-14 has been studied at a transferred four-momentum (omega,\q\) = (210 MeV, 300 MeV/c). The differential cross sections for the transitions to the ground state and the lowest excited states in C-14 were determined as a function of the momentum of the recoiling C-14 nucleus and the angle between the momentum of the proton emitted in the forward direction and the momentum transfer q. A comparison of the data to the results of calculations, performed with a microscopic model, shows clear signatures for short-range correlations in the O-16 ground state.

Published
1998

9. High-Missing-Momentum Components in the4He(e,e′p)3HReaction

Author

J. J. M. Steijger, J. J. van Leeuwe, O. Unal, C. M. Spaltro, H. J. Bulten, Rolf Ent, Antonio Pellegrino, J.M. Laget, E. Jans, L. Lapikas, J. F. J. van den Brand, W.H.A. Hesselink, C. J. G. Onderwater, Rocco Schiavilla, G. E. Dodge, Henk Blok, S. I. Nagorny, J. A. Templon, and W.J. Kasdorp

Subjects
Chemical kinetics, Physics, Reaction mechanism, General Physics and Astronomy, Impulse (physics), Few-body systems, Atomic physics, Nuclear Experiment, Wave function, Electron scattering
Abstract

The cross section of the He-4(e, e'p)H-3 reaction has been measured for missing momenta 220 less than or equal to p(m) less than or equal to 690 MeV/c to study high-momentum components of the nuclear wave function and the reaction mechanism for this transition. The zero predicted in the plane-wave impulse approximation (PWIA) cross section, due to the underlying pt momentum distribution, is found to be washed out. Three types of calculations indicate that this is caused by final-state interactions and contributions from two-body currents. The calculations reproduce the high p(m) (600-690 MeV/c) data, although due to different ingredients in the models.

Published
1998

10. Relativistic effects in the electrodisintegration of deuterium

Author

H. de Vries, W.J. Kasdorp, J. J. van Leeuwe, B. Mosconi, G. J. L. Nooren, G. van der Steenhoven, Nasser Kalantar-Nayestanaki, W.H.A. Hesselink, J.A. Tjon, L. Lapikás, Antonio Pellegrino, Th. S. Bauer, E. Jans, J. A. Templon, C. J. G. Onderwater, J. J. M. Steijger, and R. Starink

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, media_common.quotation_subject, Operator (physics), Nuclear Theory, Momentum transfer, Asymmetry, Separation, Deuterium, Invariant mass, Covariant transformation, Electron-scattering, Nuclear Experiment, Nucleon, Relativistic quantum chemistry, Momentum-transfer, media_common
Abstract

The structure function R LT and the cross-section asymmetry A φ with respect to the direction of the momentum transfer in the reaction 2 H( e , e ′ p ) have been measured at a four-momentum transfer squared of 0.2 (GeV/c) 2 , for missing momenta between 160 and 220 MeV/c at an invariant mass of 1050 MeV. For a proper description of these data calculations that include a relativistic form of the nucleon current operator are favoured. The absolute 2 H( e , e ′ p ) cross-section data favour a covariant calculation over non-relativistic calculations with relativistic corrections.

Published
1997

11. Viscosity and fission time scale ofDy156

Author

Muhsin N. Harakeh, H. van der Ploeg, G. van 't Hof, A.J.M. Plompen, Nasser Kalantar-Nayestanaki, J. C. S. Bacelar, J.P.S. van Schagen, I. Diószegi, W.H.A. Hesselink, and A. Kugler

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Viscosity, Fission, Neutron emission, Analytical chemistry, Order (ring theory), Fusion fission, Scale (descriptive set theory), Nuclear matter, Spectral line
Abstract

In the fusion-fission reaction {sup 40}Ar+{sup 116}Cd{r_arrow}{sup 156}Dy{r_arrow}fission, performed at beam energies {ital E}{sub {ital b}}=216 MeV and 238 MeV, {gamma} rays were measured in coincidence with fission fragments. The {gamma}-ray spectra are interpreted using a modified version of the statistical-model code CASCADE. From a comparison of the experimental and calculated spectra it is deduced that the nuclear viscosity is in the range 0.01{lt}{gamma}{lt}4. The extracted fission time scale is of the order of 10{sup {minus}19} s. {copyright} {ital 1996 The American Physical Society.}

Published
1996

12. Two-body currents in the reaction 12C(e,e\prime p)11B at high missing momenta

Author

Albert Zondervan, Jan Ryckebusch, L. Lapikás, E. Jans, G. van der Steenhoven, W.H.A. Hesselink, Leon Kester, Antonio Pellegrino, H. P. Blok, and (Astro)-Particles Physics

Subjects
Physics, Nuclear and High Energy Physics, Energy transfer, Atomic physics, Impulse (physics), SDG 6 - Clean Water and Sanitation, Multiplet, Excitation, Order of magnitude
Abstract

The reaction 12 C(e, e′p) 11 B has been studied in the dip region at an energy transfer ω = 212 MeV, a three-momentum transfer | q | = 270 MeV/c, and missing momenta in the range from 360 MeV/c to 600 MeV/c. Data have been obtained for the ground-state transtition and a multiplet of states centered at an excitation energy of about 7 MeV in 11 B. Distorted-wave impulse approximation calculations under-estimate the data for the ground-state transition and those for the multiplet of states by one and two orders of magnitude, respectively. Long-range correlations in the initial state bring the results of the calculations closer to the data, while two-step processes are shown to increase the calculated strength for the excitation of the multiplet of states by an order ot magnitude relative to the one-step calculations. Calculations that include two-body currents are able to give a proper account of both data sets.

Published
1996

13. Negative pion photoproduction fromN15in the region of the Δ resonance

Author

W.H.A. Hesselink, Emil Hallin, T. Gresko, Jinsook Kim, J. Shaw, K. Keeter, J.C. Bergstrom, Hyun Tai Chung, J. M. Vogt, D. M. Skopik, B. E. Norum, H. Choi, T.P. Welch, H.S. Kaplan, H.B. van den Brink, J.H. Mitchell, P. Stoler, and T. Kobayashi

Subjects
Nuclear physics, Physics, Scattering cross-section, Nuclear and High Energy Physics, Pion, Impulse (physics), Photon energy, Atomic physics, Wave function, Delta baryon
Abstract

The differential cross section for the reaction {sup 15}N({gamma},{pi}{sup {minus}}){sup 15}O{sub gs} has been measured at a photon energy of 220 MeV. We find a discrepancy between our data and a calculation based on the distorted wave impulse approximation which uses phenomenological 1{ital p}-shell wave functions. A second calculation, in which higher-shell configurations are included in the wave functions, fails to correct the discrepancy and is even more at odds with the data.

Published
1995

14. Neutral-Pion Electroproduction on the Proton near Threshold

Author

G. J. L. Nooren, J. Konijn, J. A. Templon, J. J. M. Steijger, E. Jans, Mohsen Harakeh, I. Bobeldijk, Antonio Pellegrino, R.Y. de Vries, Nasser Kalantar-Nayestanaki, H. P. Blok, R. van der Meer, B. E. Norum, Tjeerd Ketel, C. W. de Jager, W.J. Kasdorp, J. A. P. Theunissen, G. van der Steenhoven, H. B. van den Brink, W.H.A. Hesselink, L. Lapikás, C. M. Spaltro, G. E. Dodge, N. de Jonge, H. de Vries, J. J. van Leeuwe, M. A. van Uden, D. G. Ireland, E. Passchier, P.K.A. de Witt Huberts, M.C. Bouwhuis, Other Research IHEF (IoP, FNWI), and Faculty of Science

Subjects
Physics, Particle physics, Chiral perturbation theory, Pion, Proton, Meson, Computer Science::Information Retrieval, Crossing, Hadron, General Physics and Astronomy, Elementary particle, Boson
Abstract

The double-differential coincidence cross section for the reaction {sup 1}H({ital e},{ital e}{prime}{ital p}){pi}{sup 0} has been measured at {ital Q}{sup 2}=0.1(GeV/{ital c}){sup 2} in a range in the invariant mass of 2--14 MeV above threshold. From the angular dependence of the data values of the pion {ital s}-wave multipoles {ital E}{sub 0+} and {ital L}{sub 0+} have been extracted. The results are compared to predictions from chiral perturbation theory and models based on an effective Lagrangian. None of the models is able to describe both the {ital E}{sub 0+} and the {ital L}{sub 0+} multipoles.

Published
1995

15. The 12C(e, e′p) and 12C(e, e′pp) reactions in the Δ-resonance region

Author

Leon Kester, J.R. Calarco, T. P. Smith, L.J. de Bever, M.W. Kelder, Marc Vanderhaeghen, E. Jans, J. J. M. Steijger, J. Konijn, W.H.A. Hesselink, M. Kruijer, N. Kalantar-Nayestanaki, A. Pellegrino, Carlotta Giusti, Albert Zondervan, P.J. Countryman, Jan Ryckebusch, J.L. Visschers, F. W. Hersman, Franco Davide Pacati, Th.S. Bauer, J.H. Mitchell, M. Leuschner, and Other Research IHEF (IoP, FNWI)

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Meson, Proton, Nuclear Theory, Resonance (particle physics), Coincidence, Nuclear physics, Pion, Correlation function, Atomic physics, Nuclear Experiment, Electron scattering
Abstract

Coincidence cross sections for the 12 C(e, e′pp) and 12 C(e, e′p) reactions have been measured in the Δ-resonance region. The 12 C(e, e′pp) reaction has been measured at three different angular settings of the proton detectors to investigate the angular correlation between the emitted protons. The data, which have a low statistical accuracy, are compared with a calculation based on the direct-knockout mechanism, which includes one- and two-body currents. NN-correlations are accounted for via a correlation function, Δ-excitation via a two-body current and final-state interactions of the emitted protons via an optical potential. The 12 C(e, e′p) data, taken at large proton-emission angles, cover the region of high missing-energy values (145–275 MeV). The data are compared to results of a calculation taking into account meson exchange, intermediate Δ-excitation and pion production. This comparison shows that there is ample evidence for processes leading to multi-nucleon knockout.

Published
1995

16. The 13C(γ,π−)13N reaction at Eγ≈ 184 MeV (Tπ ≈ 41 MeV)

Author

H. B. van den Brink, T. Gresko, T. P. Welch, Emil Hallin, T. Kobayashi, W.H.A. Hesselink, B. E. Norum, P. Stoler, Hyun Tai Chung, D. M. Skopik, John C. Mitchell, H. Choi, J. Shaw, J. M. Vogt, and H. P. Blok

Subjects
Nuclear physics, Physics, Nuclear reaction, Nuclear and High Energy Physics, Cross section (physics), Particle physics, Pion, Nuclear Experiment, Differential (mathematics)
Abstract

Differential cross sections for the 13 C( γ , π − ) 13 N reaction at E γ ≈ 184 MeV ( T π ≈ 41 MeV) were measured with the Saskatoon tagged-photon facility and two range-telescope detectors. Data were obtained at pion angles of 45°, 60°, 80° and 100°, with emphasis on the forward angles, where the cross section shows a strong rise. The present data, together with existing ones at larger angles, are compared to several theoretical calculations.

Published
1995

17. Short-Range Nucleon-Nucleon Correlations Investigated with the ReactionC12(e,e′pp)

Author

M.W. Kelder, E. Jans, J. H. Mitchell, J. Konijn, J. R. Calarco, Franco Davide Pacati, J. J. M. Steijger, D. DeAngelis, W.H.A. Hesselink, Carlotta Giusti, Jan Visschers, Z. Papandreou, Th. S. Bauer, Leon Kester, W. Kim, Nasser Kalantar-Nayestanaki, Antonio Pellegrino, F. W. Hersman, and Albert Zondervan

Subjects
Physics, Baryon, Nuclear reaction, Particle physics, Proton, Hadron, General Physics and Astronomy, Elementary particle, Atomic physics, Nucleon, Omega, Lepton
Abstract

The reaction $^{12}C({e,e}^{\ensuremath{'}}\mathrm{pp})$ has been studied at an energy transfer $\ensuremath{\omega}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}212\phantom{\rule{0ex}{0ex}}\mathrm{MeV}$ and a three-momentum transfer $|\mathit{q}|\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}70\phantom{\rule{0ex}{0ex}}\mathrm{MeV}/c$. The measured missing-energy spectrum shows a signature for knockout of proton pairs from $(1p{)}^{2}$, $(1p,1s)$, and $(1s{)}^{2}$ states. A comparison of the data with a calculation, in which different processes leading to two-nucleon knockout are accounted for, shows that the measured cross section for the knockout of a $(1p{)}^{2}$ pair can largely be attributed to short-range nucleon-nucleon correlations.

Published
1995

18. Isomer-selected decay of the GDR in 156Dy

Author

Muhsin N. Harakeh, R.F. Noorman, W.H.A. Hesselink, and J.P.S. van Schagen

Subjects
Nuclear reaction, ENRICHED TARGET, Nuclear and High Energy Physics, Astrophysics::High Energy Astrophysical Phenomena, CD-116(AR-40,XN-GAMMA) 156-XDY, LARGE-VOLUME NAL, XN-GAMMA) 156-XDY, Spectral line, Physics::Fluid Dynamics, COMPTON-SUPPRESSED GE-DETECTOR, GIANT DIPOLE RESONANCE, SUM-SPECTROMETER, HOT ROTATING NUCLEI, Nuclear fusion, FUSION REACTIONS, CD-116(AR-40, Nuclear Experiment, ISOMERIC DECAY, Physics, MULTIPLICITY FILTER, STATISTICAL-MODEL CALCULATIONS, MEASURED E(GAMMA), STATES, E = 200 MEV, X-RAY SUM ENERGY, GAMMA-RAY MULTIPLICITY, Atomic physics, DEFORMED SHAPES
Abstract

The strength distribution of high-energy γ-rays emitted in the statistical decay of the 156 Dy ∗ compound nucleus, with E ∗ = 92.5 MeV , has been measured inclusively and for selected decay pathways in which isomers in 149 Dy, 151 Dy and 152 Dy were populated. For both spectra a deformation | β | = 0.3 is deduced and the centroid energies agree with those found from ground-state systematics. The high-energy γ-ray spectrum triggered on isomeric decay shows an increase of the width of the GDR in comparison with the inclusive spectrum.

Published
1995

19. GDR γ-ray decay in 156Dy∗ from regions selected on temperature and angular momentum

Author

W.H.A. Hesselink, H.J. Hofmann, A. van der Woude, J.P.S. van Schagen, R.F. Noorman, Yoram Alhassid, A.J.M. Plompen, J. C. S. Bacelar, Z. Sujkowski, A Stolk, Nasser Kalantar-Nayestanaki, M. N. Haraken, Brian Bush, and Research unit Nuclear & Hadron Physics

Subjects
Physics, Nuclear and High Energy Physics, Angular momentum, Thermal fluctuations, Statistical fluctuations, SHAPE FLUCTUATIONS, DY NUCLEI, Landau theory, Spectral line, HOT ROTATING NUCLEI, THERMAL FLUCTUATIONS, Excited state, GIANT-DIPOLE-RESONANCE, High Energy Physics::Experiment, DEFORMED SHAPES, Atomic physics, Ground state, SYSTEM, Bar (unit)
Abstract

The strength distribution of the GDR built on highly excited states in a restricted temperature domain in Dy-156 and Dy-155 nuclei has been deduced by subtraction of gamma-ray spectra obtained for the decay of Dy-154* and Dy-156* from regions selected on angular momentum. The resulting difference spectra have been analyzed within the statistical model. The results show a large deformation (\beta\ similar to 0.51 +/- 0.29 and 0.35 +/- 0.14) for the angular-momentum regions with [J] similar to 32 ($) over bar h at T approximate to 1.8 +/- 0.2 MeV and [J] similar to 46 ($) over bar h at T approximate to 1.7 +/- 0.2 MeV respectively, in satisfactory agreement with calculations performed in the framework of Landau theory of shape transitions and statistical fluctuations. The deduced centroid energies are in agreement with the systematics of the GDR built on the ground state. The width of the GDR shows a systematic increase with increasing temperature.

Published
1995

20. High-Momentum Protons inPb208

Author

James J. Kelly, J. A. Templon, R. van der Meer, C. Marchand, E. Passchier, I. Bobeldijk, W.H.A. Hesselink, Antonio Pellegrino, C. M. Spaltro, H. P. Blok, W.J. Kasdorp, M.N. Harakeh, L. Lapikás, G. J. L. Nooren, J. Konijn, G. E. Dodge, M. A. van Uden, H. de Vries, J. A. P. Theunissen, D. G. Ireland, E. Jans, M. Bouwhuis, C. W. de Jager, Nasser Kalantar-Nayestanaki, R.Y. de Vries, G. van der Steenhoven, N. de Jonge, J. J. van Leeuwe, H. B. van den Brink, J. J. M. Steijger, P.K.A. de Witt Huberts, Maya J. Schroevers, and R. S. Hicks

Subjects
Baryon, Physics, Nuclear reaction, Proton, Hadron, General Physics and Astronomy, Elementary particle, Atomic physics, Nucleon, Wave function, Energy (signal processing)
Abstract

High-momentum components of proton momentum distributions in $^{208}\mathrm{Pb}$ have been studied from 300 to 500 MeV/c with the ($e,{e}^{\ensuremath{'}}p$) reaction. Cross sections were measured with 180 keV excitation-energy resolution for transitions to the low-lying ${\mathrm{\textonehalf{}}}^{+}$, ${\frac{3}{2}}^{+}$, ${\frac{11}{2}}^{\ensuremath{-}}$, ${\frac{5}{2}}^{+}$, and ${\frac{7}{2}}^{+}$ states in $^{207}\mathrm{Tl}$. The data are compared to distorted-wave impulse-approximation calculations with mean-field wave functions and with wave functions that include nucleon-nucleon correlations. The data are substantially larger than mean-field predictions. The observed excess strength at low excitation energy appears to be mainly due to long-range correlations and not to short-range and tensor correlations.

Published
1994

21. The angular-momentum dependence of the giant dipole resonance in 154Dy∗

Author

Z. Sujkowski, W.H.A. Hesselink, R.F. Noorman, J. C. S. Bacelar, H.J. Hofmann, M.J.A. De Voigt, A. van der Woude, A Stolk, J.P.S. van Schagen, Nasser Kalantar-Nayestanaki, and M.N. Harakeh

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Dipole, Angular momentum, Excited state, Nuclear Theory, Gamma ray, Resonance, Atomic physics, Nuclear Experiment, Spin (physics), Excitation
Abstract

The statistical γ-ray decay of the compound nucleus 154 Dy ∗ formed at an excitation energy of 69 MeV is studied in three angular-momentum windows 〈 J 〉 = 31,42 and 50ℏ. The GDR strength function extracted from the data indicates a constant centroid energy for the resonance E GDR = 15.2 ± 0.5 MeV, a small deformation of the nuclear shape for all spin regions and an increase in the resonance width with increasing angular momentum. The latter might indicate larger shape fluctuations at higher angular momenta. A systematical study of the dependence of the extracted strength function with different methods of analysis is presented, and their discrepancies discussed.

Published
1994

22. A large-acceptance proton scintillator detection system for electron scattering experiments

Author

Leon Kester, M.N. Kruszynska, G. J. L. Nooren, J.R. Calarco, N. Kalantar-Nayestanaki, A. Pellegrino, E. Kok, J.H. Mitchell, E.A. van den Born, Th.S. Bauer, R.F. van Wijk, J. J. M. Steijger, W.H.A. Hesselink, A.N.M. Zwart, J.L. Visschers, J. Konijn, R. De Leo, Albert Zondervan, E. Jans, R. Boontje, F. A. Mul, E. Kwakkel, and P.J. Countryman

Subjects
Physics, Nuclear and High Energy Physics, Photomultiplier, Luminosity (scattering theory), Proton, Physics::Instrumentation and Detectors, Scattering, business.industry, Nuclear Theory, Scintillator, Dead time, Particle detector, Nuclear physics, Optics, Scintillation counter, Nuclear Experiment, business, Instrumentation
Abstract

Two plastic scintillator arrays with fast read-out electronics have been constructed for proton detection in an electron scattering environment. The detectors, one consisting of 47 and the other of 53 scintillators, each subtend a 39 msr solid angle and cover dynamic ranges of 25–158 and 37–198 MeV, respectively. The segmentation of the detector allows detection at forward scattering angles (> 50°) at a luminosity of 8×10 36 nucleons s −1 cm −2 (at about 1 MHz per element). The charge and time of arrival of each photomultiplier signal are digitized by two Flash ADCs. The read-out of background events is suppressed efficiently by a proper coincidence requirement in the first-level trigger. An unambiguous identification of protons and pions is obtained. The energy resolution amounts to 3.3 MeV for 87 MeV protons, while the intrinsic timing resolution is estimated at 0.6 ns.

Published
1994

23. Non-collective degrees of freedom in 192Pb

Author

R.J. Liotta, J. Blomqvist, N. Sandalescu, M. P. Carpenter, R. V. F. Janssens, W.H.A. Hesselink, A.J.M. Plompen, and Muhsin N. Harakeh

Subjects
Coupling, Physics, Nuclear and High Energy Physics, Character (mathematics), Spins, Proton, Degrees of freedom (physics and chemistry), Quasiparticle, Neutron, Atomic physics, Excitation
Abstract

Two positive-parity and two negative-parity groups of states of non-collective character with excitation energies ranging from 3 to 7 MeV and spins as high as 21 ħ have been established in 192 Pb. The main features of each group are described phenomenologically as four-quasiparticle configurations, arising from coupling of the 2 + 1 , 4 + 1 and 6 + 1 states to a specific aligned neutron two-quasiparticle configuration. Supporting evidence for this interpretation and the importance of proton excitations in this singly closed-shell nucleus is obtained from the predictions of the quasiparticle multi-step shell model (QMSM). In addition, a four-quasiparticle structure of predominant neutron character is proposed on the basis of comparisons with the experimental data on 194 Pb and with the results of the QMSM calculations.

Published
1993

24. Collective and quasiparticle structures in 192Pb

Author

Ian Gardner Bearden, R. V. F. Janssens, T. Lauritsen, D. Ye, J.P.S. van Schagen, W.H.A. Hesselink, G. van 't Hof, A.J.M. Plompen, T. L. Khoo, Y. Liang, U. Garg, Muhsin N. Harakeh, M. P. Carpenter, Nasser Kalantar-Nayestanaki, I. Ahmad, and W. Reviol

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Proton, Isotope, Nuclear Theory, Degrees of freedom (physics and chemistry), Quasiparticle, Neutron, Atomic physics, Nuclear Experiment, Excitation, Spin-½
Abstract

The structure of 192Pb has been investigated using the 173Yb(24Mg, 5n) reaction at Eb = 132 MeV. The level scheme has been extended up to an excitation energy of 7 MeV and a spin of 23 ħ. Two collective bands of levels linked by M1 transitions and four groups of states of non-collective character have been observed. Based on comparison with experimental data on odd-A Tl isotopes and with cranked shell-model calculations assuming an oblate shape, the collective Ml bands are interpreted as having an underlying proton 2-quasiparticle configuration coupled to a pair of rotation-aligned i 13 2 neutrons. The four groups of non-collective level-sequences are understood as 4-quasiparticle excitations associated with aligned neutron 2-quasiparticle states that involve a mixture of neutron and proton degrees of freedom.

Published
1993

25. GDR dissipation and nuclear shape in hot fast-rotating Dy nuclei

Author

A.J.M. Plompen, A. van der Woude, J. C. S. Bacelar, A. Stolk, R.F. Noorman, J.P.S. van Schagen, Nasser Kalantar-Nayestanaki, Yoram Alhassid, H.J. Hofmann, W.H.A. Hesselink, Mohsen Harakeh, Z. Sujkowski, and Brian Bush

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Angular momentum, HIGH-SPIN, Nuclear Theory, FLUCTUATIONS, Deformation (meteorology), Dissipation, Nuclear physics, Total angular momentum quantum number, Beta (plasma physics), Excited state, GIANT-DIPOLE-RESONANCE, Angular momentum coupling, Atomic physics, Nuclear Experiment, DECAY
Abstract

The statistical gamma-ray decay of the GDR built on excited states in Dy nuclei has been investigated for selected domains of angular momentum up to about 70hBAR and temperatures in the range 1-2 MeV. The GDR strength distributions extracted from the data indicate large average nuclear deformations (beta approximately 0.35) at high angular momentum and average temperatures T greater-than-or-equal-to 1.5 MeV. This experimental observation is supported by results from calculations in which thermal shape fluctuations are taken into account around an oblate equilibrium deformation beta(eq) Although this equilibrium deformation increases with angular momentum, the calculations show rather large and constant average deformations [beta] approximately 0.35.

Published
1993

26. Lack of evidence for a superdeformed band inPb192

Author

T. L. Khoo, W. Reviol, Y. Liang, I. Ahmad, U. Garg, Nasser Kalantar-Nayestanaki, M. P. Carpenter, W.H.A. Hesselink, G. van 't Hof, A.J.M. Plompen, D. Ye, Ian Gardner Bearden, T. Lauritsen, R. V. F. Janssens, J.P.S. van Schagen, and Muhsin N. Harakeh

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Nuclear magnetic resonance, medicine.anatomical_structure, Nuclear Theory, medicine, Measure (mathematics), Nucleus
Abstract

An experiment was performed to measure the lifetimes of the states in the superdeformed band reported in $^{192}\mathrm{Pb}$. No evidence for such a band was found, despite the fact that the experimental conditions were nearly identical to those of an earlier measurement where this band was proposed. The problems and questions encountered in the analysis are described. The arguments presented here indicate that further measurements are needed to establish the existence of a superdeformed band in this nucleus unambiguously.

Published
1993

27. Collective oblate bands inPb196

Author

R. G. Henry, B. Fornal, M. P. Carpenter, J. R. B. Oliveira, W.H.A. Hesselink, D. T. Vo, T. L. Khoo, J. R. Hughes, E. Rubel, R. M. Diamond, Ian Gardner Bearden, T. Lauritsen, P. J. Daly, W. Reviol, M. J. Brinkman, J. E. Draper, Jolie Cizewski, C. Duyar, M. A. Deleplanque, U. Garg, A.J.M. Plompen, M. A. Stoyer, Y. Liang, F. S. Stephens, T. F. Wang, Z. W. Grabowski, R. H. Mayer, E. A. Henry, R. V. F. Janssens, Nasser Kalantar-Nayestanaki, W. H. Kelly, J. Burde, A. Kuhnert, J. A. Becker, D. Nissius, F. Soramel, and Iftikhar Ahmad

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Spins, Computer Science::Information Retrieval, Yrast, Hadron, Quasiparticle, Atomic physics, Spin (physics), Nucleon, Excitation
Abstract

Evidence for collective oblate behavior in [sup 196]Pb is presented. One irregular and two regular bands of [ital M]1 transitions have been observed following the [sup 170]Er([sup 30]Si,4[ital n]) and [sup 176]Yb([sup 26]Mg,6[ital n]) reactions. Transitions linking the most intense regular band to the low-lying negative-parity yrast levels are observed, establishing excitation energies, spins, and probable parities of the band members. In contrast, no such transitions have been found for the irregular band and the weaker regular band. The bands are interpreted as corresponding to collective oblate rotation, arising mainly from deformation-aligned high-[ital j], shape-driving quasiproton excitations across the [ital Z]=82 shell gap, coupled to rotation-aligned quasineutrons.

Published
1993

28. The reactions in the dip region

Author

Z. Papandreou, Albert Zondervan, Th. S. Bauer, J. Konijn, J. J. M. Steijger, Antonio Pellegrino, M.W. Kelder, E. Jans, W.H.A. Hesselink, M. Kruijer, J.M. Mitchell, W. Kim, Jan Visschers, J. R. Calarco, F. W. Hersman, Nasser Kalantar-Nayestanaki, Leon Kester, and P. C. Countryman

Subjects
Physics, Nuclear and High Energy Physics, Electron spectrometer, Proton, Energy transfer, Nuclear Theory, Detector, Momentum transfer, Angular correlation, Position (vector), Physics::Accelerator Physics, Atomic physics, Nuclear Experiment, Conjugate
Abstract

The reactions 12 C (e,e′pp) and 12 C (e,e′p) have been studied at an energy transfer ω = 210 MeV and a momentum transfer ‖q‖ = 267 MeV/c. The angular correlation between two emitted protons has been measured keeping the position of the electron spectrometer and one proton detector fixed, while the position of the other detector was varied around the conjugate angle. A clear signature for the emission of two correlated protons has been observed.

Published
1993

29. Investigation of the ExclusiveHe3(e,e′pn)H1Reaction

Author

W.H.A. Hesselink, T. Hehl, J. C. McGeorge, D. P. Watts, L. Lapikas, P. Grabmayr, H. P. Blok, C. Ayerbe, Jan C. Bernauer, J. Garcia Llongo, Th. Pospischil, Damir Bosnar, F. Moschini, H. de Vries, Jacek Golak, Andreas Nogga, Johann-Ludwig Heim, U. Müller, M. Ases Antelo, R. Perez-Benito, M. O. Distler, M. Ding, M. Weiss, Th. Walcher, D. Baumann, J. Bermuth, B. Zihlmann, J. R. M. Annand, M. Potokar, G. Rosner, Michael Seimetz, D. I. Glazier, D. G. Middleton, W. Glöckle, P. Barneo, Harald Merkel, J.M. Friedrich, M. Weinriefer, G. Jover Mañas, R. Skibiński, E. Jans, P. Merle, Hiroyuki Kamada, R. Böhm, I. Martin, H. Witała, K. Monstad, Michael Kohl, and I. J. D. MacGregor

Subjects
Momentum, Nuclear physics, Recoil proton, Physics, Energy transfer, Nuclear Theory, Momentum transfer, Continuum (design consultancy), General Physics and Astronomy, Few-body systems, Atomic physics, Nuclear Experiment
Abstract

Cross sections for the ^3He(e,e′pn)^1H reaction were measured for the first time at energy transfers of 220 and 270 MeV for several momentum transfers ranging from 300 to 450 MeV/c. Cross sections are presented as a function of the momentum of the recoil proton and the momentum transfer. Continuum Faddeev calculations using the Argonne V18 and Bonn-B nucleon-nucleon potentials overestimate the measured cross sections by a factor 5 at low recoil proton momentum with the discrepancy becoming smaller at higher recoil proton momentum.

Published
2009

30. A scintillator detector system for electron scattering experiments

Author

Antonio Pellegrino, G. J. L. Nooren, Albert Zondervan, J. J. M. Steijger, E. Jans, W.H.A. Hesselink, and Th. S. Bauer

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, Physics::Instrumentation and Detectors, business.industry, Nuclear Theory, Resolution (electron density), Detector, Scintillator, Kinetic energy, Nuclear physics, Optics, Hodoscope, Physics::Accelerator Physics, Angular resolution, Nuclear Experiment, business, Instrumentation, Electron scattering
Abstract

We have constructed and operated two highly segmented scintillator detectors for use in electron scattering experiments. The detectors cover a solid angle of 40 msr each, while one detector accepts protons with a kinetic energy between 25 and 158 MeV and the other between 37 and 198 MeV. Hodoscope planes provide an angular resolution of 15 × 16.5 mrad (hor. × ver.). The energy resolution we obtained is 2 MeV (FWHM) for 91 MeV protons, and the coincidence timing resolution with respect to the QDQ spectrometer at NIKHEF-K is 0.9 ns (FWHM).

Published
1991

31. 3He(e, epp) and 3He(e, epn) reactions at AmPS and MAMI

Author

P. Merle, B. Zihlmann, K. Monstad, D. P. Watts, U. Müller, D. I. Glazier, T. Hehl, I. Martin, J. C. McGeorge, J. Garcia Llongo, D. Baumann, Th. Walcher, G. Rosner, J. Bermuth, M. Potokar, R. Böhm, M. Weinriefer, D. Bosnar, M. Ases Antelo, M. Kohl, C. Ayerbe, G. Jover Mañas, P. Grabmayr, F. Moschini, I. J. D. MacGregor, P. Barneo, Th. Pospischil, E. Jans, J. R. M. Annand, M. O. Distler, J.M. Friedrich, Johann-Ludwig Heim, M. Ding, M. Weiss, R. Pérez Benito, M. Seimitz, W.H.A. Hesselink, D. G. Middleton, L. Lapikás, Harald Merkel, H. P. Blok, Jan C. Bernauer, and H. de Vries

Subjects
Nuclear physics, Baryon, Physics, Nuclear reaction, Faddeev equations, electron scattering on nuclei, nucleon-nucleon correlations, Hadron, Neutron, Elementary particle, Nucleon, Atomic and Molecular Physics, and Optics, Lepton
Abstract

This paper reports on measurements of the 3He(e, epp) reaction measured at AmPS and the 3He(e, epn) reaction measured at MAMI. The measurements were performed in similar kinematics to allow a comparison to be made between the cross sections of the two reactions. Results are shown for both reactions together with a comparison for the 3He(e, e epp) data with continuum Faddeev calculations.

Published
2008

32. Transverse polarization ofΛandΛ¯hyperons in quasireal photoproduction

Author

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

Subjects
Physics, HERMES experiment, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Hyperon, Lambda, Lambda baryon, Polarization (waves), 01 natural sciences, Particle identification, Nuclear physics, Transverse plane, Light cone, 0103 physical sciences, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

The HERMES experiment has measured the transverse polarization of Lambda and {ovr Lambda} hyperons produced inclusively in quasireal photoproduction at a positron beam energy of 27.6 GeV. The transverse polarization P{sub n}{sup Lambda} of the Lambda hyperon is found to be positive while the observed {ovr Lambda} polarization is compatible with zero. The values averaged over the kinematic acceptance of HERMES are P{sub n}{sup Lambda} =0.078 {+-} 0.006(stat) {+-} 0.012(syst) and P{sub n}{sup {ovr Lambda}} = -0.025 {+-} 0.015(stat) {+-} 0.018(syst) for Lambda and {ovr Lambda}, respectively. The dependences of P{sub n}{sup Lambda} and P{sub n}{sup {ovr Lambda}} on the fraction zeta of the beam's light-cone momentum carried by the hyperon and on the hyperon's transverse momentum p{sub T} were investigated. The measured Lambda polarization rises linearly with p{sub 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
2007

33. Precise determination of the spin structure function g(1) of the proton, deuteron, and neutron

Author

L. A. Linden-Levy, W.-D. Nowak, V. A. Gapienko, P. Zupranski, J. Streit, L. Felawka, I.A. Savin, N. Meyners, G. Rosner, W. Augustyniak, Shan Wang, G. P. Capitani, H. Böttcher, Andreas Schäfer, N. Bianchi, L. Rubacek, L. Lapikás, D. Veretennikov, G. Schnell, A. Funel, A. Nagaitsev, G. van der Steenhoven, A. Osborne, Salvatore Frullani, U. Stosslein, H. Ohsuga, Arne Vandenbroucke, L. Lagamba, Z. Akopov, Riccardo Fabbri, J. G. Rubin, P. F. Dalpiaz, Y. Naryshkin, Hidekazu Tanaka, G. Iarygin, P. Tait, Morgan Murray, T. A. Shibata, R.O. Avakian, Tetsuya Hasegawa, F. Giordano, A. Rostomyan, A. R. Reolon, Tsutomu Kobayashi, Y. Salomatin, M. Contalbrigo, A. Avetissian, P. Lenisa, A. Trzcinski, H. E. Jackson, H. Marukyan, N. Akopov, V. G. Krivokhijine, A. Airapetian, H. P. Blok, Y. X. Ye, M. Statera, A. Brull, B. Marianski, Martin Raithel, E. Devitsin, Wolfgang Lorenzon, E. C. Aschenauer, V. Shutov, A. Kisselev, B. Q. Ma, K. Garrow, Ivana Hristova, Hasko Stenzel, M. Capiluppi, C. Vogel, B. Hommez, C. Weiskopf, Alessandra Fantoni, M. Hoek, I. Sanjiev, G. Gapienko, F. Stinzing, J. Stewart, V. A. Kozlov, D. Reggiani, M. Ehrenfried, K. Rith, R. De Leo, P. E. Reimer, V. A. Korotkov, Michael Tytgat, Naomi C R Makins, R. Perez-Benito, B. Tchuiko, M. Kopytin, B. Maiheu, J. Dreschler, V. Vikhrov, M. Hartig, M. Demey, O. Grebeniouk, M. Stancari, Wouter Deconinck, P. Di Nezza, S. Taroian, P. Liebing, J. Lu, I. M. Gregor, Andrey V. Izotov, A. Jgoun, S. Yen, C. Shearer, B. Seitz, A. Borissov, Valeria Muccifora, C. Riedl, Ralf Kaiser, U. Elschenbroich, W.H.A. Hesselink, Y. Van Haarlem, M. Diefenthaler, E. Steffens, J. Seele, P. B. van der Nat, K. P. Schüler, E. De Sanctis, T. Michler, G. Elbakian, Franco Garibaldi, A. Hillenbrand, G. Gavrilov, H. Guler, A. Borysenko, A. Gute, A. Andrus, Eugenio Nappi, V. Mexner, E. Avetissian, N. Pickert, O. Mikloukho, Dirk Ryckbosch, M. Negodaev, S. Lu, Adel Terkulov, C. A. Miller, Y. Gärber, D. Gabbert, Y. J. Mao, P. Kravchenko, F. Masoli, T. Keri, J. J. M. Steijger, Michael Düren, A. Elalaoui-Moulay, Frank Ellinghaus, B. Zihlmann, E. R. Kinney, Cynthia Marie Hadjidakis, Y. Miyachi, D. Hasch, S. Belostotski, V. Bryzgalov, K. Sinram, L. De Nardo, Zhenyu Ye, V. Gharibyan, A. Reischl, B. Krauss, G. Ciullo, Y. Holler, A. Ivanilov, (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education

Subjects
Physics, HERMES experiment, Nuclear and High Energy Physics, Proton, FOS: Physical sciences, 14.20.Dh, 13.88.+e, 13.60.Hb, 13.60.−r, HERA, Inelastic scattering, High Energy Physics - Experiment, NO, Nuclear physics, High Energy Physics - Experiment (hep-ex), Deuterium, High Energy Physics::Experiment, Neutron, ddc:530, Atomic physics, Nuclear Experiment, Nucleon, Spin-½
Abstract

Precise measurements of the spin structure functions of the proton $g_1^p(x,Q^2)$ and deuteron $g_1^d(x,Q^2)$ are presented over the kinematic range $0.0041 \leq x \leq 0.9$ and $0.18 $ GeV$^2$ $\leq Q^2 \leq 20$ GeV$^2$. The data were collected at the HERMES experiment at DESY, in deep-inelastic scattering of 27.6 GeV longitudinally polarized positrons off longitudinally polarized hydrogen and deuterium gas targets internal to the HERA storage ring. The neutron spin structure function $g_1^n$ is extracted by combining proton and deuteron data. The integrals of $g_1^{p,d}$ at $Q^2=5$ GeV$^2$ are evaluated over the measured $x$ range. Neglecting any possible contribution to the $g_1^d$ integral from the region $x \leq 0.021$, a value of $0.330 \pm 0.011\mathrm{(theo.)}\pm0.025\mathrm{(exp.)}\pm 0.028$(evol.) is obtained for the flavor-singlet axial charge $a_0$ in a leading-twist NNLO analysis.

Published
2007

34. First measurements of the ^16O(e,e'pn)^14N reaction

Author

Th. Pospischil, Frank Klein, P. Bartsch, Johann-Ludwig Heim, Carlo Barbieri, H. de Vries, L. Lapikás, M. Weis, D. Bauman, H. Schmieden, S. Grözinger, T. Hehl, U. Müller, G. Rosner, Michael Kohl, Carlotta Giusti, J. C. McGeorge, Harald Merkel, P. Barneo, Jrm Annand, P. Merle, W.H.A. Hesselink, P. Grabmayr, I. J. D. MacGregor, D. I. Glazier, E. Jans, R. Böhm, A. Süle, Michael Seimetz, J.M. Friedrich, D. Elsner, H. P. Blok, M. Ding, D. Bosnar, F. Moschini, Th. Walcher, B. Zihlmann, D. G. Middleton, M. O. Distler, I. Martin, D. P. Watts, and J. Bermuth

Subjects
Physics, Nuclear and High Energy Physics, Resolution (electron density), Magnitude (mathematics), FOS: Physical sciences, Energy–momentum relation, Kinematics, Residual, Momentum, medicine.anatomical_structure, medicine, Atomic physics, Nuclear Experiment (nucl-ex), Nuclear Experiment, Nucleus
Abstract

This paper reports on the first measurement of the ^16O(e,e'pn)^14N reaction. Data were measured in kinematics centred on a super-parallel geometry at energy and momentum transfers of 215 MeV and 316 MeV/c. The experimental resolution was sufficient to distinguish groups of states in the residual nucleus but not good enough to separate individual states. The data show a strong dependence on missing momentum and this dependence appears to be different for two groups of states in the residual nucleus. Theoretical calculations of the reaction using the Pavia code do not reproduce the shape or the magnitude of the data., Comment: 10 pages, 11 figures, 2 tables, Accepted for publication in EPJA

Published
2007
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35. Beam-charge azimuthal asymmetry and deeply virtual Compton scattering

Author

A. Airapetian, A. Reischl, L. Lagamba, C. Shearer, B. Seitz, Z. Akopov, Shan Wang, H. Ohsuga, Klaus Rith, U. Elschenbroich, F. Stinzing, P. B. van der Nat, H. Y. Lu, A. Borissov, V. A. Gapienko, A. Nagaitsev, S. Frullani, G. Ciullo, M. Demey, C. A. Miller, N. Pickert, Dirk Ryckbosch, A. Rostomyan, A. R. Reolon, A. Avetissian, P. F. Dalpiaz, V. A. Korotkov, G. Iarygin, I. M. Gregor, R. Seidl, Hidekazu Tanaka, M. Stancari, M. Beckmann, A. Elalaoui-Moulay, Frank Ellinghaus, W.-D. Nowak, E. R. Kinney, M. Statera, A. Laziev, P. E. Reimer, K. Garrow, N. Akopov, L. Rubacek, Andrey V. Izotov, M. Bouwhuis, H. Böttcher, V. A. Kozlov, J. Seele, Valeria Muccifora, H. Marukyan, A. Osborne, Y. Naryshkin, Y. X. Ye, G. Gapienko, A. Hillenbrand, G. Elbakian, J. Volmer, Alessandra Fantoni, A. Funel, M. Hoek, A. Ivanilov, J. Stewart, K. P. Schüler, P. Zupranski, Y. J. Mao, P. Tait, B. Maiheu, A. Brull, B. Tchuiko, M. Kopytin, M. Contalbrigo, Tsutomu Kobayashi, L. Felawka, M. Amarian, W. Augustyniak, A. Andrus, Martin Raithel, Eugenio Nappi, E. De Sanctis, T. Michler, Y. Salomatin, S. Lu, E. C. Aschenauer, J. J. M. Steijger, M. Negodaev, Michael Düren, G. van der Steenhoven, V. Shutov, B. Krauss, G. P. Capitani, Adel Terkulov, I. Sanjiev, F. Masoli, Naomi C R Makins, Michael Tytgat, E. Avetissian, D. Balin, Nicola Bianchi, O. Mikloukho, W.H.A. Hesselink, G. Schnell, T. Chen, D. Gaskell, A. Jgoun, B. Q. Ma, H. E. Jackson, M. Hartig, N. Meyners, G. Rosner, L. A. Linden-Levy, K. Oganessyan, Y. Holler, S. Taroian, A. Borysenko, V. G. Krivokhijine, M. Ehrenfried, B. Marianski, J. Lu, C. Vogel, S. Yen, P. Lenisa, R. De Leo, Rezo Shanidze, A. Trzcinski, Ralf Kaiser, S. Belostotski, V. Bryzgalov, Wouter Deconinck, P. Di Nezza, F. Garibaldi, P. Liebing, E. Steffens, J. Dreschler, G. Gavrilov, V. Vikhrov, K. Sinram, L. De Nardo, Zhenyu Ye, Manuella Vincter, Hasko Stenzel, M. Capiluppi, L. Lapikás, I.A. Savin, J. G. Rubin, V. Gharibyan, V. Mexner, K. Hafidi, Morgan Murray, Y. Van Haarlem, B. Zihlmann, P. Bailey, T. A. Shibata, Cynthia Marie Hadjidakis, Y. Miyachi, R.O. Avakian, Andreas Schäfer, J. Wendland, W. Sommer, D. Hasch, D. H. Potterveld, E. Devitsin, A. Kisselev, Arne Vandenbroucke, Riccardo Fabbri, D. Reggiani, O. Grebeniouk, C. Riedl, H. P. Blok, Wolfgang Lorenzon, Ivana Hristova, B. Hommez, (Astro)-Particles Physics, and Photo Conversion Materials

Subjects
HERMES experiment, Elastic scattering, Physics, Nuclear and High Energy Physics, Particle physics, Photon, Scattering, media_common.quotation_subject, High Energy Physics::Phenomenology, Compton scattering, FOS: Physical sciences, DESY, HERA, 13.60.Fz Elastic and Compton scattering, 14.20.Dh, 24.85.+p, Asymmetry, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), ddc:530, High Energy Physics::Experiment, Nuclear Experiment, media_common
Abstract

The first observation of an azimuthal cross section asymmetry with respect to the charge of the incoming lepton beam is reported from a study of hard exclusive electroproduction of real photons. The data have been accumulated by the HERMES experiment at DESY, in which the HERA 27.6 GeV electron or positron beam scattered off an unpolarized hydrogen gas target. The observed asymmetry is attributed to the interference between the Bethe-Heitler process and the deeply virtual Compton scattering (DVCS) process. The interference term is sensitive to DVCS amplitudes, which provide the most direct access to generalized parton distributions. © 2007 The American Physical Society.

Published
2007

36. Beam-spin asymmetries in the azimuthal distribution of pion electroproduction

Author

V. A. Korotkov, Wouter Deconinck, V. Mexner, J. Lu, S. Yen, B. Zihlmann, G. Elbakian, Y. Miyachi, H. Guler, Ralf Kaiser, B. Hommez, A. Nagaitsev, A. Borissov, M. Demey, G. Iarygin, H. Marukyan, E. Steffens, Dirk Ryckbosch, Hasko Stenzel, A. Airapetian, P. Lenisa, I.A. Savin, I. M. Gregor, V. Kozlov, A. Brull, G. Gavrilov, J. G. Rubin, A. Andrus, A. Trzcinski, B. Marianski, K. Sinram, L. De Nardo, T. Keri, Tsutomu Kobayashi, Y. J. Mao, P. Kravchenko, O. Grebeniouk, A. Elalaoui-Moulay, Frank Ellinghaus, E. R. Kinney, S. Lu, Y. Naryshkin, M. Negodaev, G.P. Capitani, M. Statera, S. Frullani, F. Stinzing, H. E. Jackson, V. G. Krivokhijine, Andreas Schäfer, N. Pickert, L. Felawka, M. Amarian, H. P. Blok, A. R. Reolon, T. A. Shibata, Adel Terkulov, C. Vogel, A. Funel, W.H.A. Hesselink, V. Muccifora, V. Vikhrov, J. J. M. Steijger, Michael Düren, Michael Tytgat, Y. Salomatin, Wolfgang Lorenzon, M. Stancari, P. E. Reimer, L. Lagamba, P. Di Nezza, P. Bailey, G. van der Steenhoven, C. A. Miller, Arne Vandenbroucke, P. Zupranski, Morgan Murray, R.O. Avakian, L. Rubacek, Riccardo Fabbri, B. Krauss, S. Taroian, K. P. Schüler, A. Fantoni, Ivana Hristova, H. Avakian, P.F. Dalpiaz, B. Q. Ma, A. Borysenko, F. Giordano, Alessandro Bacchetta, W. Augustyniak, M. Contalbrigo, E. Devitsin, O. Mikloukho, M. Ehrenfried, N. Meyners, Martin Raithel, W.-D. Nowak, R. De Leo, J. Stewart, K. Garrow, G. Rosner, E. C. Aschenauer, A. Kisselev, V. Shutov, A. Osborne, R. Seidl, E. Avetisyan, E. De Sanctis, T. Michler, Klaus Rith, V. Gharibyan, K. Oganessyan, I. Sanjiev, H. Böttcher, Naomi C R Makins, J. Streit, F. Masoli, S. Belostotski, D. Reggiani, M. Hartig, V. Bryzgalov, F. Garibaldi, C. Hadjidakis, P. Tait, J. Dreschler, M. Capiluppi, P. Liebing, Andrey V. Izotov, Z. Akopov, D. Hasch, Z. Ye, Hidekazu Tanaka, A. Jgoun, Y. Van Haarlem, C. Riedl, G. Gapienko, Shan Wang, H. Ohsuga, A. Rostomyan, A. Avetissian, K. Hafidi, M. Diefenthaler, J. Seele, A. Hillenbrand, A. Ivanilov, A. Reischl, Y. Holler, G. Ciullo, Tetsuya Hasegawa, V. A. Gapienko, N. Bianchi, R. Perez-Benito, B. Maiheu, C. Shearer, B. Seitz, E. Nappi, U. Elschenbroich, L. Lapikás, P. B. van der Nat, Y. X. Ye, L. A. Linden-Levy, M. Hoek, G. Schnell, B. Tchuiko, M. Kopytin, (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education

Subjects
Nuclear and High Energy Physics, Meson, Hadron, FOS: Physical sciences, Virtual particle, Inelastic scattering, 01 natural sciences, 7. Clean energy, 24.85.+p, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Pion, 13.88.+e, 0103 physical sciences, ddc:530, SDG 7 - Affordable and Clean Energy, 010306 general physics, Nuclear Experiment, 13.60.-r, Physics, 010308 nuclear & particles physics, 13.87.Fh, 14.20.Dh, HERA, Science General, Scattering amplitude, Physics::Accelerator Physics, High Energy Physics::Experiment, Dimensionless quantity
Abstract

A measurement of the beam-spin asymmetry in the azimuthal distribution of pions produced in semi-inclusive deep-inelastic scattering off protons is presented. The measurement was performed using the HERMES spectrometer with a hydrogen gas target and the longitudinally polarized 27.6 GeV positron beam of HERA. The sinusoidal amplitude of the dependence of the asymmetry on the angle ϕ of the hadron production plane around the virtual photon direction relative to the lepton scattering plane was measured for π + π + , π − π − and π 0 π 0 mesons. The dependence of this amplitude on the Bjorken scaling variable and on the pion fractional energy and transverse momentum is presented. The results are compared to theoretical model calculations.

Published
2007

37. A silicon micro-strip telescope for the HERMES experiment: a design study

Author

K. Fiedler, G. van der Steenhoven, W.H.A. Hesselink, M.G. Guidal, J. J. M. Steijger, M. van Beuzekom, A. Siriphant, J. Visser, E. Kok, and (Astro)-Particles Physics

Subjects
Physics, HERMES experiment, Nuclear and High Energy Physics, Silicon, business.industry, Scattering, Physics::Instrumentation and Detectors, Detector, chemistry.chemical_element, DESY, law.invention, Telescope, Nuclear physics, Optics, Recoil, chemistry, law, High Energy Physics::Experiment, SDG 7 - Affordable and Clean Energy, business, Instrumentation, Lepton
Abstract

The construction of a silicon telescope as a possible extension of the HERMES experiment at DESY is under study. The challenge is to build a detector that is able to detect both slow recoiling hadrons, and fast (nearly minimum ionising) particles produced in deep-inelastic lepton scattering. The detector should cover a large area for a large geometric acceptance, and it should be mounted inside the scattering chamber thus lowering the threshold for the detection of low-energy recoil products. The impact of the large dynamic range of the signals on the design of the read-out electronics is also addressed. © 1998 Elsevier Science B.V. All rights reserved.

Published
1998

38. Double-hadron leptoproduction in the nuclear medium

Author

V. A. Korotkov, Klaus Rith, M. Stancari, J. Stewart, J. J. M. Steijger, A. Brüll, Michael Düren, G. Elbakian, D. Veretennikov, A. Airapetian, B. Zihlmann, K. Sinram, L. De Nardo, Zhenyu Ye, V. Gharibyan, W. Augustyniak, Cynthia Marie Hadjidakis, Y. Miyachi, D. Hasch, A. Funel, F. Giordano, P. Di Nezza, G. van der Steenhoven, M. Demey, Shan Wang, H. Ohsuga, A. Osborne, P. Liebing, R. Seidl, F. Stinzing, Hasko Stenzel, V. A. Gapienko, I. M. Gregor, G. Iarygin, M. Capiluppi, P. Lenisa, L. A. Linden-Levy, H. Böttcher, Michael Tytgat, A. Trzcinski, W.H.A. Hesselink, W.-D. Nowak, Tsutomu Kobayashi, A. Borysenko, H. Marukyan, J. G. Rubin, A. Rostomyan, A. Avetissian, S. Taroian, L. Lapikás, Dirk Ryckbosch, B. Hommez, Frank Ellinghaus, J. Streit, S. Lu, Adel Terkulov, G. Gapienko, I.A. Savin, E. R. Kinney, O. Grebeniouk, C. Riedl, C. Vogel, Salvatore Frullani, P. Tait, P. Bailey, L. Lagamba, H. Guler, Z. Akopov, Y. Naryshkin, P. F. Dalpiaz, Eugenio Nappi, A. Borissov, V. Vikhrov, A. R. Roelon, J. Dreschler, Hidekazu Tanaka, R. Perez-Benito, B. Maiheu, A. Andrus, H. E. Jackson, Andreas Schäfer, H. P. Blok, M. Negodaev, Morgan Murray, A. Jgoun, B. Krauss, Y. Van Haarlem, B. Marianski, Wolfgang Lorenzon, Tetsuya Hasegawa, Valeria Muccifora, Ivana Hristova, Y. Salomatin, K. P. Schüler, S. Belostotski, P. Zupranski, B. Q. Ma, V. Bryzgalov, M. Ehrenfried, R. De Leo, E. Avetissian, Nicola Bianchi, O. Mikloukho, Arne Vandenbroucke, N. Meyners, G. Rosner, Riccardo Fabbri, I. Sanjiev, K. Garrow, V. A. Kozlov, L. Felawka, M. Amarian, A. Nagaitsev, G. P. Capitani, G. Schnell, N. Akopov, Y. J. Mao, P. Kravchenko, V. G. Krivokhijine, F. Masoli, P. E. Reimer, M. Contalbrigo, Y. X. Ye, Martin Raithel, E. C. Aschenauer, V. Shutov, C. Shearer, B. Seitz, Naomi C R Makins, U. Elschenbroich, T. Keri, P. B. van der Nat, M. Hartig, J. Lu, Alessandra Fantoni, Wouter Deconinck, S. Yen, M. Hoek, K. A. Griffioen, Ralf Kaiser, B. Tchuiko, M. Kopytin, E. Steffens, G. Gavrilov, V. Mexner, T. A. Shibata, R.O. Avakian, A. Ivanilov, A. Reischl, E. Devitsin, A. Kisselev, G. Ciullo, D. Reggiani, Y. Holler, E. De Sanctis, T. Michler, Franco Garibaldi, M. Diefenthaler, J. Seele, A. Hillenbrand, N. Pickert, C. A. Miller, A. Elalaoui-Moulay, M. Statera, Andrey V. Izotov, L. Rubacek, (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education

Subjects
Particle physics, Nuclear Theory, FOS: Physical sciences, General Physics and Astronomy, chemistry.chemical_element, Inelastic scattering, 25.30.Rw, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Xenon, ddc:550, 13.60.−r, 13.87.Fh, 25.75.Gz, Nuclear Experiment, Physics, Scattering, High Energy Physics::Phenomenology, Krypton, HERA, Nuclear matter, Deep inelastic scattering, chemistry, Deuterium, High Energy Physics::Experiment
Abstract

Physical review letters 96, 162301 (2006). doi:10.1103/PhysRevLett.96.162301, Published by APS, College Park, Md.

Published
2006

39. Longitudinal spin transfer to the Lambda hyperon in semiinclusive deep-inelastic scattering

Author

B. Hommez, B. Marianski, K. Sinram, L. De Nardo, A. Osborne, B. Krauss, Zhenyu Ye, Y. Van Haarlem, A. Borissov, V. Gharibyan, K. Hafidi, R. Seidl, P. E. Reimer, M. Bouwhuis, H. Böttcher, M. Diefenthaler, Morgan Murray, G. Iarygin, J. Seele, B. Zihlmann, V. Vikhrov, Manuella Vincter, A. Hillenbrand, Houbing Lu, P. Tait, J. Dreschler, A. Andrus, Cynthia Marie Hadjidakis, Y. Miyachi, J. Wendland, W. Sommer, M. Demey, M. Negodaev, D. Hasch, D. H. Potterveld, Dirk Ryckbosch, H. Marukyan, S. Belostotski, V. Bryzgalov, P. Bailey, I. M. Gregor, Y. Salomatin, Tsutomu Kobayashi, W. Augustyniak, M. Statera, Arne Vandenbroucke, Riccardo Fabbri, C. Vogel, B. Q. Ma, H. P. Blok, M. Beckmann, M. Ehrenfried, R. De Leo, Wolfgang Lorenzon, Andrey V. Izotov, Klaus Rith, J. J. M. Steijger, Michael Düren, T. A. Shibata, V. A. Korotkov, R.O. Avakian, A. Elalaoui-Moulay, Frank Ellinghaus, H. Ohsuga, Ivana Hristova, E. R. Kinney, M. Stancari, A. Jgoun, E. Devitsin, C. Riedl, Y. Naryshkin, Michael Tytgat, H. E. Jackson, A. Kisselev, V. G. Krivokhijine, A. Brüll, P. Lenisa, A. Trzcinski, N. Pickert, D. Reggiani, W.-D. Nowak, G. Elbakian, T. Chen, S. Taroian, C. A. Miller, Eugenio Nappi, S. I. Manaenkov, A. Nagaitsev, K. Oganessyan, A. Rostomyan, Salvatore Frullani, A. Funel, A. R. Reolon, A. Avetissian, G. van der Steenhoven, P. F. Dalpiaz, A. Borysenko, G. Gapienko, K. P. Schüler, I.A. Savin, Andreas Schäfer, E. De Sanctis, T. Michler, Franco Garibaldi, C. Shearer, B. Seitz, B. Maiheu, E. Avetissian, D. Balin, Nicola Bianchi, N. Akopov, O. Mikloukho, U. Elschenbroich, P. B. van der Nat, Y. J. Mao, P. Kravchenko, V. A. Gapienko, P. Di Nezza, P. Liebing, F. Masoli, J. G. Rubin, A. Laziev, H. C. Chiang, Song-Ming Wang, Y. X. Ye, Alessandra Fantoni, M. Hoek, B. Tchuiko, M. Kopytin, T. Keri, Wouter Deconinck, V. Mexner, Hidekazu Tanaka, K. Garrow, V. A. Kozlov, P. Zupranski, L. Lagamba, Z. Akopov, N. Meyners, J. Lu, G. Rosner, S. Yen, Ralf Kaiser, A. Airapetian, E. Steffens, F. Stinzing, G. Gavrilov, Xian Chen, J. Volmer, A. Ivanilov, L. Felawka, M. Amarian, X. R. Lu, M. Contalbrigo, G. P. Capitani, Martin Raithel, E. C. Aschenauer, G. Schnell, V. Shutov, I. Sanjiev, Naomi C R Makins, M. Hartig, A. Reischl, G. Ciullo, L. Rubacek, O. Grebeniouk, L. A. Linden-Levy, Y. Holler, L. Lapikás, J. Stewart, W.H.A. Hesselink, Valeria Muccifora, S. Lu, Adel Terkulov, Hasko Stenzel, M. Capiluppi, (Astro)-Particles Physics, and Photo Conversion Materials

Subjects
HERMES experiment, Nuclear and High Energy Physics, Particle physics, Lambda baryon, Lambda, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, Positron, 13.88.+e, 0103 physical sciences, ddc:530, 13.60.−r, 13.60.Rj, SDG 7 - Affordable and Clean Energy, 010306 general physics, Physics, 010308 nuclear & particles physics, Scattering, Hyperon, HERA, Deep inelastic scattering, Physics::Accelerator Physics, High Energy Physics::Experiment
Abstract

The transfer of polarization from a high-energy positron to a {lambda}{sup 0} hyperon produced in semiinclusive deep-inelastic scattering has been measured. The data have been obtained by the HERMES experiment at DESY using the 27.6 GeV longitudinally polarized positron beam of the HERA collider and unpolarized gas targets internal to the positron (electron) storage ring. The longitudinal spin-transfer coefficient is found to be D{sub LL{sup '}}{sup {lambda}}=0.11{+-}0.10(stat){+-}0.03(syst) at an average fractional energy carried by the {lambda}{sup 0} hyperon =0.45. The dependence of D{sub LL{sup '}}{sup {lambda}} on both the fractional energy z and the fractional longitudinal momentum x{sub F} is presented.

Published
2006

40. Quasifreeπ0andπ−Electroproduction onHe4in theΔ-Resonance Region

Author

L. Todor, W.H.A. Hesselink, M. F. van Batenburg, Y. Jun, Tancredi Botto, P. Heimberg, H. P. Blok, Igor Passchier, D. J. J. de Lange, David Groep, B. E. Norum, L. Lapikás, G. E. Dodge, Douglas Higinbotham, E. Jans, Th. S. Bauer, Tjeerd Ketel, H. de Vries, M. F. M. Steenbakkers, and R. Starink

Subjects
Physics, Nuclear magnetic resonance, General Physics and Astronomy, Resonance
Published
2005

41. Measurement of the tensor structure function b1 of the deuteron

Author

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

Subjects
HERMES experiment, Particle physics, media_common.quotation_subject, FOS: Physical sciences, General Physics and Astronomy, Spin structure, Inelastic scattering, Asymmetry, High Energy Physics - Experiment, 14.65.−q, Nuclear physics, High Energy Physics - Experiment (hep-ex), 13.88.+e, SDG 7 - Affordable and Clean Energy, Nuclear Experiment, media_common, Physics, 13.60.−r, 14.20.Dh, Scattering, Momentum transfer, HERA, Deep inelastic scattering, High Energy Physics::Experiment
Abstract

The \Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6 GeV/c positron beam of \Hera. The use of a tensor polarized deuteron gas target with only a negligible residual vector polarization enabled the first measurement of the tensor asymmetry $\At$ and the tensor structure function $\bd$ for average values of the Bj��rken variable $0.01<< x>

Published
2005

42. Subleading-twist effects in single-spin asymmetries in semi-inclusive deep-inelastic scattering on a longitudinally polarized hydrogen target

Author

P. Zupranski, P. Lenisa, L. Felawka, M. Amarian, Houbing Lu, A. Trzcinski, L. Lagamba, P. Di Nezza, C. Shearer, B. Seitz, E. Nappi, V. Muccifora, F. Masoli, S. Belostotski, G. Iarygin, V. Bryzgalov, A. Funel, G. van der Steenhoven, U. Elschenbroich, W.H.A. Hesselink, A. Borysenko, P. Bailey, G. Schnell, F. Garibaldi, N. Meyners, G. Rosner, Y. Salomatin, P. B. van der Nat, A. R. Reolon, Wouter Deconinck, H. Marukyan, Tsutomu Kobayashi, Andrey V. Izotov, J. Volmer, D. Hasch, P. E. Reimer, Hasko Stenzel, T. Chen, K. Hafidi, M. Negodaev, Z. Akopov, C. A. Miller, W. Augustyniak, M. Diefenthaler, A. Ivanilov, M. Contalbrigo, Martin Raithel, V. Mexner, S. Lu, G. Gapienko, Adel Terkulov, A. Fantoni, T. A. Shibata, Hidekazu Tanaka, E. C. Aschenauer, V. Shutov, V. A. Gapienko, R.O. Avakian, B. Q. Ma, I. Sanjiev, E. De Sanctis, T. Michler, B. Krauss, A. Nagaitsev, V. Gharibyan, A. Reischl, Dirk Ryckbosch, N. Bianchi, Naomi C R Makins, E. Devitsin, A. Kisselev, A. Osborne, T. Keri, D. Reggiani, M. Ehrenfried, H. E. Jackson, K. Garrow, V. G. Krivokhijine, A. Airapetian, V. A. Korotkov, J. Seele, J. Dreschler, R. De Leo, M. Demey, A. Hillenbrand, S. Frullani, A. Laziev, J. Lu, S. Yen, I. M. Gregor, F. Stinzing, L. Rubacek, A. Andrus, Michael Tytgat, Y. Holler, N. Pickert, Song-Ming Wang, N. Akopov, Ralf Kaiser, A. Elalaoui-Moulay, Frank Ellinghaus, S. Taroian, Y. X. Ye, G.P. Capitani, E. R. Kinney, E. Steffens, Y. J. Mao, H. Ohsuga, G. Elbakian, M. Hoek, Y. Naryshkin, G. Gavrilov, J. Stewart, B. Tchuiko, M. Kopytin, A. Rostomyan, A. Brüll, V. Vikhrov, A. Jgoun, Manuella Vincter, A. Avetissian, M. Statera, Y. Van Haarlem, C. Riedl, C. Vogel, Morgan Murray, R. Seidl, M. Bouwhuis, H. Böttcher, B. Maiheu, P. Tait, G. Ciullo, K. Sinram, L. De Nardo, Zhenyu Ye, B. Zihlmann, L. A. Linden-Levy, Y. Miyachi, J. Wendland, W. Sommer, D. H. Potterveld, L. Lapikás, M. Hartig, M. Capiluppi, P. Liebing, K. P. Schüler, B. Hommez, P.F. Dalpiaz, J. J. M. Steijger, Michael Düren, M. Stancari, D. Balin, O. Mikloukho, E. Avetissian, J. G. Rubin, A. Borissov, M. Beckmann, Klaus Rith, B. Marianski, C. Hadjidakis, I.A. Savin, Andreas Schäfer, W.-D. Nowak, Arne Vandenbroucke, Riccardo Fabbri, Alessandro Bacchetta, H. P. Blok, Wolfgang Lorenzon, Ivana Hristova, K. Oganessyan, V. Kozlov, O. Grebeniouk, (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education

Subjects
Quark, Nuclear and High Energy Physics, Particle physics, Proton, Meson, Nuclear Theory, FOS: Physical sciences, Inelastic scattering, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Pion, 13.60.-r, 13.88.+e, 14.20.Dh, 14.65.-q, 0103 physical sciences, SDG 14 - Life Below Water, 010306 general physics, Nuclear Experiment, Spin-½, Physics, 010308 nuclear & particles physics, Scattering, High Energy Physics::Phenomenology, Deep inelastic scattering, Physics::Accelerator Physics, High Energy Physics::Experiment
Abstract

Single-spin asymmetries in the semi-inclusive production of charged pions in deep-inelastic scattering from transversely and longitudinally polarized proton targets are combined to evaluate the subleading-twist contribution to the longitudinal case. This contribution is significantly positive for π + mesons and dominates the asymmetries on a longitudinally polarized target previously measured by Hermes . The subleading-twist contribution for π − mesons is found to be small.

Published
2005

43. Search for an exoticS=−2,Q=−2baryon resonance at a mass near 1862 MeV in quasireal photoproduction

Author

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

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Resonance, Lambda baryon, 01 natural sciences, Baryon, Particle decay, Exotic baryon, 0103 physical sciences, Mass spectrum, Invariant mass, Atomic physics, 010306 general physics
Abstract

A search for an exotic baryon resonance with $S=\ensuremath{-}2$, $Q=\ensuremath{-}2$ has been performed in quasireal photoproduction on a deuterium target through the decay channel ${\ensuremath{\Xi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\Lambda}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}$. No evidence for a previously reported ${\ensuremath{\Xi}}^{--}(1860)$ resonance is found in the ${\ensuremath{\Xi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}$ 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 ${\ensuremath{\Xi}}^{0}(1530)$ is found to be between 9 and 24 nb.

Published
2005

44. Comparison between the transverse responses of the reactionsC12(e,e'p)B11andC12(γ,p)B11

Author

T. Davinson, Jan Ryckebusch, G. DeMeyer, E. C. Aschenauer, D. Branford, S. A. Morrow, David Groep, J.E. Ducret, L. Lapikás, Nasser Kalantar-Nayestanaki, R. Medaglia, M. F. van Batenburg, R. Starink, D. Boersma, J. F. Arneil, John A. Mackenzie, K. Hicks, G. van der Steenhoven, C. Marchand, M. A. van Uden, D. G. Ireland, H. P. Blok, W.H.A. Hesselink, M. Liang, M. Van Sambeek, and H. de Vries

Subjects
Nuclear physics, Physics, Parallel kinematics, Nuclear and High Energy Physics, Transverse plane, Structure function, High resolution, Atomic physics, Two-body problem, Electron scattering
Abstract

A study of the reaction C-12(e,e'p)B-11 in parallel kinematics has been made for the missing-momentum region 250

Published
2005

45. Flavor decomposition of the sea-quark helicity distributions in the nucleon from semiinclusive deep inelastic scattering

Author

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

Subjects
Quark, Particle physics, Meson, High Energy Physics::Lattice, Nuclear Theory, Hadron, FOS: Physical sciences, General Physics and Astronomy, 13.60.–r, Inelastic scattering, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Pion, 13.88.+e, Nuclear Experiment, 14.20.Dh, 14.65.–q, QC, Physics, High Energy Physics::Phenomenology, Quark model, Deep inelastic scattering, Baryon, High Energy Physics::Experiment
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., Comment: 5 pages, 3 figures

Published
2004

46. The HERMES Polarized Hydrogen and Deuterium Gas Target in the HERA Electron Storage Ring

Author

G. Graw, Y. Salomatin, V. A. Gapienko, N. Bianchi, V. A. Korotkov, K. Sinram, L. De Nardo, M. Ehrenfried, R. De Leo, B. Hommez, W. Haeberli, Y. Van Haarlem, R. Seidl, J. G. Rubin, L. Lapikás, M. Bouwhuis, H. Böttcher, L. Rubacek, J. Seele, P. Tait, Michael Tytgat, E. Avetissian, K. Garrow, H. Ohsuga, Dirk Ryckbosch, A. Airapetian, Klaus Rith, G. Elbakian, W. Augustyniak, S. Lu, D. Heesbeen, B. Zihlmann, L. A. Linden-Levy, S. Taroian, Adel Terkulov, H. E. Jackson, V. G. Krivokhijine, H. P. Blok, A. Borissov, Y. Miyachi, J. Wendland, C. Baumgarten, W. Sommer, A. Reischl, F. Stinzing, Wolfgang Lorenzon, B. Maiheu, A. Rostomyan, A. Avetissian, D. H. Potterveld, Z. Akopov, G. Iarygin, J. Stewart, A. Brüll, C. Hadjidakis, Bo-Qiang Ma, R. Mussa, Ivana Hristova, G. Schnell, C. A. Miller, P. Bailey, J. Wilbert, P. E. Reimer, Rezo Shanidze, M. Henoch, G. Gapienko, Arne Vandenbroucke, G. van der Steenhoven, V. Vikhrov, Manuella Vincter, A. Nagaitsev, Michel Vetterli, A. Fantoni, E. De Sanctis, V. Kozlov, A. Laziev, Riccardo Fabbri, M. Statera, Hidekazu Tanaka, D. Reggiani, W.H.A. Hesselink, A. Borysenko, G. Ciullo, K. P. Schüler, P.F. Dalpiaz, N. Koch, B. Braun, T. Kobayashi, N. Akopov, O. Grebeniouk, Z. Ye, Y. Mao, P. Lenisa, V. Gharibyan, J. J. M. Steijger, Michael Düren, A. Trzcinski, J. Volmer, M. Stancari, T. Wise, C. Schill, A. Jgoun, Y. X. Ye, A. Ivanilov, A. Fechtchenko, C. Vogel, D. Balin, O. Mikloukho, M. Beckmann, W.-D. Nowak, A. R. Reolon, C. Shearer, Hasko Stenzel, C. Riedl, L. Felawka, B. Seitz, M. Amarian, E. Nappi, K. Hafidi, V. Mexner, I.A. Savin, L. Lagamba, V. Muccifora, U. Elschenbroich, M. Demey, P. Zupranski, P. Di Nezza, H. Kolster, Y. Holler, K. Oganessyan, P. B. van der Nat, I. M. Gregor, N. Meyners, G. Rosner, A. Osborne, Ralf Hertenberger, T. A. Shibata, M. Hartig, G.P. Capitani, Andrey V. Izotov, R.O. Avakian, M. Hoek, D. Hasch, B. Marianski, G.R. Court, G. V. Ybeles Smit, M. Capiluppi, B. Tchuiko, M. Kopytin, A. Nass, S. Frullani, P. Liebing, N. Pickert, E. Devitsin, J. Lu, A. Kisselev, S. Yen, Ralf Kaiser, E. Steffens, A. Hillenbrand, G. Gavrilov, M. Contalbrigo, Martin Raithel, T. Chen, E. C. Aschenauer, V. Shutov, I. Sanjiev, Naomi C R Makins, H. Marukyan, Houbing Lu, S. Belostotski, A. Andrus, V. Bryzgalov, M. Negodaev, F. Garibaldi, Sihui Wang, A. Elalaoui-Moulay, Frank Ellinghaus, E. R. Kinney, Y. Naryshkin, B. Krauss, (Astro)-Particles Physics, and Photo Conversion Materials

Subjects
29.25.Pj, Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, Hydrogen, Atomic Physics (physics.atom-ph), chemistry.chemical_element, FOS: Physical sciences, 07.60.F, Electron, 01 natural sciences, Physics - Atomic Physics, NO, 07.77, 29.25.-t, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Physics::Atomic Physics, 010306 general physics, Instrumentation, Physics, 67.65, 010308 nuclear & particles physics, DESY, HERA, Instrumentation and Detectors (physics.ins-det), Polarization (waves), 29.25.P, chemistry, Deuterium, Cathode ray, Atomic physics, Nucleon
Abstract

The HERMES hydrogen and deuterium nuclear-polarized gas targets have been in use since 1996 with the polarized electron beam of HERA at DESY to study the spin structure of the nucleon. Polarized atoms from a Stern-Gerlach Atomic Beam Source are injected into a storage cell internal to the HERA electron ring. Atoms diffusing from the center of the storage cell into a side tube are analyzed to determine the atomic fraction and the atomic polarizations. The atoms have a nuclear polarization, the axis of which is defined by an external magnetic holding field. The holding field was longitudinal during 1996-2000, and was changed to transverse in 2001. The design of the target is described, the method for analyzing the target polarization is outlined, and the performance of the target in the various running periods is presented. © 2004 Elsevier B.V. All rights reserved.

Published
2004
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47. Evidence for a narrow |S|=1 baryon state at a mass of 1528 MeV in quasi-real photoproduction

Author

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

Subjects
Nuclear and High Energy Physics, Particle physics, Nuclear Theory, FOS: Physical sciences, 01 natural sciences, NO, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), 0103 physical sciences, Invariant mass, 12.39.Mk, 13.60.-r, 13.60.Rj, 14.20.-c, 010306 general physics, Nuclear Experiment, Physics, Isovector, 010308 nuclear & particles physics, State (functional analysis), Pentaquark, Baryon, Deuterium, Exotic baryon, Mass spectrum, High Energy Physics::Experiment
Abstract

Evidence for a narrow baryon state is found in quasi-real photoproduction on a deuterium target through the decay channel p K^0_S --> p pi^+ pi^-. A peak is observed in the p K^0_S invariant mass spectrum at 1528 +/- 2.6 (stat) +/-2.1 (syst) MeV. Depending on the background model,the naive statistical significance of the peak is 4--6 standard deviations and its width may be somewhat larger than the experimental resolution of sigma=4.3 -- 6.2 MeV. This state may be interpreted as the predicted S=+1 exotic Theta^{+}(uuddbar(s)) pentaquark baryon. No signal for an hypothetical Theta^{++} baryon was observed in the pK^+ invariant mass distribution. The absence of such a signal indicates that an isotensor Theta is excluded and an isovector Theta is unlikely., 8 pages, 4 figures

Published
2003

48. Q2Dependence of Nuclear Transparency for Exclusiveρ0Production

Author

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

Subjects
HERMES experiment, Physics, Nuclear reaction, Particle physics, Meson, Nuclear Theory, Hadron, General Physics and Astronomy, Virtual particle, Coherence length, Nuclear physics, Nuclear transparency, High Energy Physics::Experiment, Nuclear Experiment, Nucleon
Abstract

Exclusive coherent and incoherent electroproduction of the rho(0) meson from H-1 and N-14 targets has been studied at the HERMES experiment as a function of coherence length (l(c)), corresponding to the lifetime of hadronic fluctuations of the virtual photon, and squared four-momentum of the virtual photon (-Q(2)). The ratio of N-14 to H-1 cross sections per nucleon, called nuclear transparency, was found to increase (decrease) with increasing l(c) for coherent (incoherent) rho(0) electroproduction. For fixed l(c), a rise of nuclear transparency with Q(2) is observed for both coherent and incoherent rho(0) production, which is in agreement with theoretical calculations of color transparency.

Published
2003

49. Quark fragmentation to π±, π0, K±, p and p_bar in the nuclear environment

Author

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

Subjects
HERMES experiment, Quark, Nuclear and High Energy Physics, Meson, Nuclear Theory, Hadron, chemistry.chemical_element, 13.87.Fh, 13.60.-r, 14.20.-c, 14.40.-n, 01 natural sciences, 7. Clean energy, Nuclear physics, 0103 physical sciences, Multiplicity (chemistry), Nuclear Experiment, 010306 general physics, Physics, 010308 nuclear & particles physics, Krypton, Baryon, Deuterium, chemistry, High Energy Physics::Experiment, Atomic physics
Abstract

The influence of the nuclear medium on lepto-production of hadrons was studied in the HERMES experiment at DESY in semi-inclusive deep-inelastic scattering of 27.6 GeV positrons off deuterium, nitrogen and krypton targets. The differential multiplicity for krypton relative to that of deuterium has been measured for the first time for various identified hadrons (π+, π−, π0, K+, K−, p and p ) as a function of the virtual photon energy ν, the fraction z of this energy transferred to the hadron, and the hadron transverse momentum squared pt2. The multiplicity ratio is strongly reduced in the nuclear medium at low ν and high z, with significant differences among the various hadrons. The distribution of the hadron transverse momentum is broadened towards high pt2 in the nuclear medium, in a manner resembling the Cronin effect previously observed in collisions of heavy ions and protons with nuclei.

Published
2003

50. Evidence for Quark-Hadron Duality in the Proton Spin Asymmetry $A_1$

Author

Michel Vetterli, N. Akopov, F. Menden, B. Hommez, Klaus Rith, D. Heesbeen, L. G. Greeniaus, E. De Sanctis, U. Stosslein, Franco Garibaldi, C. A. Miller, S. Yen, C. Weiskopf, L. Lagamba, A. Jgoun, B. D. Fox, B. Zihlmann, Z. Akopov, J. Ely, Ralf Kaiser, G. Schnell, A. Rostomyan, A. R. Reolon, A. Avetissian, G. M. Urciuoli, J. Stewart, E. Steffens, E. Kotik, A. Brüll, G. Hofman, W. Haeberli, G. Gavrilov, V. V. Ammosov, F. Masoli, J. Visser, F. Sato, A. Reischl, K. Negodaeva, A. Fechtchenko, G. S. Kyle, I.A. Savin, K. Sinram, H. J. Bulten, L. De Nardo, B. Tipton, K. P. Schüler, U. Elschenbroich, M. Amarian, R. Van de Vyver, G. Ciullo, H. P. Blok, S. Yoneyama, Evaristo Cisbani, Valeria Muccifora, V. Gharibyan, L. Felawka, G. Iarygin, Christian Schill, S. Brauksiepe, B. Krauss, E. Avetissian, Nicola Bianchi, O. Mikloukho, Wolfgang Lorenzon, S. Potashov, H. Zohrabian, C. Scarlett, P. Bailey, H. Marukyan, G. P. Capitani, G.R. Court, Axel Maas, Andreas Schäfer, Eugenio Nappi, J. Franz, Andrey V. Izotov, A. Airapetian, P. Kitching, G. van der Steenhoven, J. Wendland, Michael Tytgat, P.W. Green, D. H. Potterveld, M. Bouwhuis, H. Böttcher, P. Di Nezza, F.H. Heinsius, Frank Ellinghaus, S. Taroian, V. Mexner, T. Lindemann, E. R. Kinney, V. Rappoport, P. Liebing, T. Wise, V. A. Korotkov, A. Schwind, R. Shanidze, S. Podiatchev, F. Schmidt, Martin Raithel, R. J. Holt, Y. Naryshkin, M. Beckmann, J. F. J. van den Brand, E. C. Aschenauer, V. Shutov, O. Grebeniouk, M. Stancari, Salvatore Frullani, J. J. M. Steijger, I. Sanjiev, P. F. Dalpiaz, K. Königsmann, Michael Düren, G. Orlandi, Naomi C R Makins, V. Baturin, S. Tessarin, P. Lenisa, J. Seibert, V. A. Kozlov, B. W. Filippone, D. Reggiani, J. Volmer, G. Elbakian, S. Belostotski, S. Bernreuther, Adel Terkulov, Yasuhiro Sakemi, M. Ehrenfried, R. De Leo, Erika Garutti, Y. Holler, V. Vikhrov, M. C. Simani, Manuella Vincter, Y. Gärber, P.K.A. de Witt Huberts, M. Hartig, E. Thomas, H. Avakian, Ralf Hertenberger, W.H.A. Hesselink, A. Gute, Dirk Ryckbosch, Othmane Bouhali, P. E. Reimer, M. Henoch, K. Suetsugu, R. Fabbri, T. A. Shibata, R.O. Avakian, H. E. Jackson, V. G. Krivokhijine, E. Devitsin, C. Baumgarten, N. Meyners, A. Borissov, K. Hafidi, V. A. Gapienko, H. Kolster, Alessandra Fantoni, G. Graw, M. Kopytin, A. Nass, Peter Jung, B. Seitz, D. Hasch, A. Laziev, K. Oganessyan, J. Wilbert, W.-D. Nowak, I. Brunn, A. Kisselev, H. Fischer, Jeffrey Brack, A. Nagaitsev, (Astro)-Particles Physics, and Photo Conversion Materials

Subjects
Quark, Particle physics, media_common.quotation_subject, Hadron, Nuclear Theory, FOS: Physical sciences, General Physics and Astronomy, Inelastic scattering, 01 natural sciences, Asymmetry, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Q(2)-DEPENDENCE, 0103 physical sciences, Proton spin crisis, SCATTERING, 010306 general physics, Nuclear Experiment, media_common, Physics, 010308 nuclear & particles physics, SUM, CONSTRAINTS, Deep inelastic scattering, 3. Good health, Baryon, POLARIMETER, NEUTRON, High Energy Physics::Experiment, POLARIZED HYDROGEN, Nucleon, RESONANCES, BEHAVIOR
Abstract

Spin-dependent lepton-nucleon scattering data have been used to investigate the validity of the concept of quark-hadron duality for the spin asymmetry $A_1$. Longitudinally polarised positrons were scattered off a longitudinally polarised hydrogen target for values of $Q^2$ between 1.2 and 12 GeV$^2$ and values of $W^2$ between 1 and 4 GeV$^2$. The average double-spin asymmetry in the nucleon resonance region is found to agree with that measured in deep-inelastic scattering at the same values of the Bjorken scaling variable $x$. This finding implies that the description of $A_1$ in terms of quark degrees of freedom is valid also in the nucleon resonance region for values of $Q^2$ above 1.6 GeV$^2$., 5 pages, 1 eps figure, table added, new references added, in print in Phys. Rev. Lett

Published
2002

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