Inclusive Measurements of Inelastic Electron and Positron Scattering from Unpolarized Hydrogen and Deuterium Targets
The HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, S. Belostotski, N. Bianchi, H. P. Blok, A. Borissov, J. Bowles, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, L. De Nardo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Dueren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, R. Fabbri, A. Fantoni, L. Felawka, S. Frullani, D. Gabbert, G. Gapienko, V. Gapienko, F. Garibaldi, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Golembiovskaya, C. Hadjidakis, M. Hartig, D. Hasch, G. Hill, A. Hillenbrand, M. Hoek, Y. Holler, I. Hristova, Y. Imazu, A. Ivanilov, H. E. Jackson, H. S. Jo, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, V. Korotkov, V. Kozlov, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, R. Lamb, L. Lapikas, I. Lehmann, P. Lenisa, L. A. Linden-Levy, A. Lopez Ruiz, W. Lorenzon, X. -G. Lu, X. -R. Lu, B. -Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, L. Manfre, Y. Mao, B. Marianski, A. Martinez de la Ossa, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, V. Muccifora, M. Murray, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W. -D. Nowak, L. L. Pappalardo, R. Perez-Benito, N. Pickert, M. Raithel, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, F. Sanftl, A. Schaefer, G. Schnell, K. P. Schueler, B. Seitz, T. -A. Shibata, V. Shutov, M. Stancari, M. Statera, E. Steffens, J. J. M. Steijger, H. Stenzel, J. Stewart, F. Stinzing, S. Taroian, A. Trzcinski, M. Tytgat, A. Vandenbroucke, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, V. Vikhrov, I. Vilardi, C. Vogel, S. Wang, S. Yaschenko, H. Ye, Z. Ye, S. Yen, W. Yu, D. Zeiler, B. Zihlmann, P. Zupranski
TL;DR
This work delivers high-statistics inclusive measurements of inelastic electron and positron scattering from unpolarized hydrogen and deuterium with HERMES, extracting the structure functions $F_2^p$ and $F_2^d$ via a world-data $R$ parameterization. It spans a broad kinematic regime, including a largely uncharted region ($Q^2\lesssim1$ GeV$^2$, $15<W^2<45$ GeV$^2$), and confronts the data with Regge-motivated ALLM fits to the photon-nucleon cross section, yielding GD11-P and GD11-D parameterizations. The analysis provides the deuteron-to-proton cross-section ratio with reduced uncertainties and delivers updated global fits to cross sections and ratios, refining constraints on parton distributions and the transition between perturbative and non-perturbative QCD. Overall, the results are consistent with existing world data and extend the kinematic coverage, contributing precise inputs for global analyses of nucleon structure in the DIS regime.
Abstract
Results of inclusive measurements of inelastic electron and positron scattering from unpolarized protons and deuterons at the HERMES experiment are presented. The structure functions $F_2^p$ and $F_2^d$ are determined using a parameterization of existing data for the longitudinal-to-transverse virtual-photon absorption cross-section ratio. The HERMES results provide data in the ranges $0.006\leq x\leq 0.9$ and 0.1 GeV$^2\leq Q^2\leq$ 20 GeV$^2$, covering the transition region between the perturbative and the non-perturbative regimes of QCD in a so-far largely unexplored kinematic region. They are in agreement with existing world data in the region of overlap. The measured cross sections are used, in combination with data from other experiments, to perform fits to the photon-nucleon cross section using the functional form of the ALLM model. The deuteron-to-proton cross-section ratio is also determined.