The Q(2)-dependence of the generalised Gerasimov-Drell-Hearn integral for the deuteron, proton and neutron

Airapetian, A. and Akopov, N. and Akopov, Z. and Amarian, M. and Ammosov, V. V. and Aschenauer, E. C. and Avakian, R. and Avetissian, A. and Avetissian, E. and Bailey, P. and Baturin, V. and Baumgarten, C. and Beckmann, M. and Belostotski, S. and Bernreuther, S. and Bianchi, N. and Blok, H. P. and Boettcher, H. and Borissov, A. and Bouhali, O. and Bouwhuis, M. and Brack, J. and Brauksiepe, S. and Bruell, A. and Brunn, I. and Capitani, G. P. and Chiang, H. C. and Ciullo, G. and Court, G. R. and Dalpiaz, P. F. and De Leo, R. and De Nardo, L. and De Sanctis, E. and Devitsin, E. and Di Nezza, P. and Dueren, M. and Ehrenfried, M. and Elalaoui-Moulay, A. and Elbakian, G. and Ellinghaus, F. and Elschenbroich, U. and Ely, J. and Fabbri, R. and Fantoni, A. and Fechtchenko, A. and Felawka, L. and Fischer, H. and Fox, B. and Franz, J. and Frullani, S. and Gaerber, Y. and Gapienko, G. and Gapienko, V. and Garibaldi, F. and Garutti, E. and Gavrilov, G. and Gharibyan, V. and Graw, G. and Grebeniouk, O. and Green, P. W. and Greeniaus, L. G. and Gute, A. and Haeberli, W. and Hafidi, K. and Hartig, M. and Hasch, D. and Heesbeen, D. and Heinsius, F. H. and Henoch, M. and Hertenberger, R. and Hesselink, W. H. A. and Hillenbrand, A. and Holler, Y. and Hommez, B. and Iarygin, G. and Izotov, A. and Jackson, H. E. and Jgoun, A. and Kaiser, R. and Kinney, E. and Kisselev, A. and Kitching, P. and Koenigsmann, K. and Kolster, H. and Kopytin, M. and Korotkov, V. and Kotik, E. and Kozlov, V. and Krauss, B. and Krivokhijine, V. G. and Lagamba, L. and Lapikas, L. and Laziev, A. and Lenisa, P. and Liebing, P. and Lindemann, T. and Lipka, K. and Lorenzon, W. and Makins, N. C. R. and Marukyan, H. and Masoli, F. and Menden, F. and Mexner, V. and Meyners, N. and Mikloukho, O. and Miller, C. A. and Miyachi, Y. and Muccifora, V. and Nagaitsev, A. and Nappi, E. and Naryshkin, Y. and Nass, A. and Nowak, W. D. and Oganessyan, K. and Ohsuga, H. and Orlandi, G. and Podiatchev, S. and Potashov, S. and Potterveld, D. H. and Raithel, M. and Reggiani, D. and Reimer, P. E. and Reisch, A. and Reolon, A. R. and Rith, K. and Rosner, G. and Rostomyan, A. and Ryckbosch, D. and Sanjiev, I. and Sato, F. and Savin, I. and Scarlett, C. and Schaefer, A. and Schill, C. and Schnell, G. and Schueler, K. P. and Schwind, A. and Seibert, J. and Seitz, B. and Shanidze, R. and Shibata, T. A. and Shutov, V. and Simani, M. C. and Sinram, K. and Stancari, M. and Statera, M. and Steffens, E. and Steijger, J. J. M. and Stewart, J. and Stoesslein, U. and Suetsugu, K. and Tanaka, H. and Taroian, S. and Terkulov, A. and Teryaev, O. and Tessarin, S. and Thomas, E. and Tkabladze, A. and Tytgat, M. and Urciuoli, G. M. and van der Nat, P. and van der Steenhoven, G. and van de Vyver, R. and Vetterli, M. C. and Vikhrov, V. and Vincter, M. G. and Visser, J. and Vogt, M. and Volmer, J. and Weiskopf, C. and Wendland, J. and Wilbert, J. and Wise, T. and Yen, S. and Yoneyama, S. and Zihlmann, B. and Zohrabian, H. and Zupranski, P. (2003) The Q(2)-dependence of the generalised Gerasimov-Drell-Hearn integral for the deuteron, proton and neutron. EUROPEAN PHYSICAL JOURNAL C, 26 (4). pp. 527-538. ISSN 1434-6044, 1434-6052

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Abstract

The Gerasimov-Drell-Hearn (GDH) sum rule connects the anomalous contribution to the magnetic moment of the target nucleus with an energy-weighted integral of the difference of the helicity-dependent photoabsorption cross sections. Originally conceived for real photons, the GDH integral can be generalised to the case of photons with virtuality Q(2). For spin-1/2 targets such as the nucleon, it then represents the non-perturbative limit of the first moment Gamma(1) of the spin structure function g(1)(x,Q(2)) in deep inelastic scattering (DIS). The data collected by HERMES with a deuterium target are presented together with a re-analysis of previous measurements on the proton. This provides an unprecedented and complete measurement of the generalised GDH integral for photon-virtuality ranging over 1.2 < Q(2) < 12.0 GeV2 and for photon-nucleon invariant mass squared W-2 ranging over I < W2 < 45 GeV2. thus covering simultaneously the nucleon-resonance and the deep inelastic scattering regions. These data allow the study of the Q(2)-dependence of the full GDH integral, which is sensitive to both the Q(2)-evolution of the resonance form factors and contributions of higher twist. The contribution of the nucleon-resonance region is seen to decrease rapidly with increasing Q(2). The DIS contribution is sizeable over the full measured range, even down to the lowest measured Q(2). As expected, at higher Q(2) the data are found to be in agreement with previous measurements of the first moment of g(1). From data on the deuteron and proton, the GDH integral for the neutron has been derived and the proton-neutron difference evaluated. This difference is found to satisfy the fundamental Bjorken sum rule at Q(2) = 5 GeV2.

Item Type: Article
Uncontrolled Keywords: SPIN STRUCTURE-FUNCTION; DEEP-INELASTIC SCATTERING; STRUCTURE-FUNCTION G(1); SUM-RULE; RESONANCE REGION; POLARIZED HYDROGEN; NUCLEON; POLARIMETER; EXTRACTION; TARGET;
Subjects: 500 Science > 530 Physics
Divisions: Physics > Institute of Theroretical Physics > Chair Professor Schäfer > Group Andreas Schäfer
Depositing User: Dr. Gernot Deinzer
Date Deposited: 24 Aug 2021 12:35
Last Modified: 24 Aug 2021 12:35
URI: https://pred.uni-regensburg.de/id/eprint/39302

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