Measurement of the neutron F2 structure function via spectator tagging with CLAS.

/ Authors

N. Baillie, S. Tkachenko, J. Zhang, P. Bosted, S. Bültmann, M. Christy, H. Fenker, K. Griffioen, C. Keppel, S. Kuhn

and 140 more authors

W. Melnitchouk, V. Tvaskis, K. Adhikari, D. Adikaram, M. Aghasyan, M. Amaryan, M. Anghinolfi, J. Arrington, H. Avakian, H. Baghdasaryan, M. Battaglieri, A. Biselli, D. Branford, W. Briscoe, W. Brooks, V. Burkert, D. Carman, A. Celentano, S. Chandavar, G. Charles, P. Cole, M. Contalbrigo, V. Crede, A. D’Angelo, A. Daniel, N. Dashyan, R. Vita, E. Sanctis, A. Deur, B. Dey, C. Djalali, G. Dodge, J. Domingo, D. Doughty, R. Dupré, D. Dutta, R. Ent, H. Egiyan, A. Alaoui, Lamiaa El Fassi, L. Elouadrhiri, P. Eugenio, G. Fedotov, S. Fegan, A. Fradi, M. Gabrielyan, N. Gevorgyan, G. Gilfoyle, K. Giovanetti, F. Girod, W. Gohn, E. Golovatch, R. Gothe, L. Graham, B. Guegan, M. Guidal, N. Guler, L. Guo, K. Hafidi, D. Heddle, K. Hicks, M. Holtrop, E. Hungerford, C. Hyde, Y. Ilieva, D. Ireland, M. Ispiryan, E. Isupov, S. Jawalkar, H. Jo, N. Kalantarians, M. Khandaker, P. Khetarpal, A. Kim, W. Kim, P. King, A. Klein, F. Klein, A. Klimenko, V. Kubarovsky, S. Kuleshov, N. Kvaltine, K. Livingston, H. Lu, I. MacGregor, Y. Mao, N. Markov, B. McKinnon, T. Mineeva, B. Morrison, H. Moutarde, E. Munevar, P. Nadel-Turonski, A. Ni, S. Niccolai, I. Niculescu, G. Niculescu, M. Osipenko, A. Ostrovidov, L. Pappalardo, K. Park, S. Park, E. Pasyuk, S. Pereira, S. Pisano, S. Pozdniakov, J. Price, S. Procureur, Y. Prok, D. Protopopescu, B. Raue, G. Ricco, D. Rimal, M. Ripani, G. Rosner, P. Rossi, F. Sabatié, M. Saini, C. Salgado, D. Schott, R. Schumacher, E. Seder, Y. Sharabian, D. Sober, D. Sokhan, S. Stepanyan, S. Stepanyan, P. Stoler, S. Strauch, M. Taiuti, W. Tang, M. Ungaro, M. Vineyard, E. Voutier, D. Watts, L. Weinstein, D. Weygand, M. Wood, L. Zana, B. Zhao

/ Abstract

We report on the first measurement of the F(2) structure function of the neutron from the semi-inclusive scattering of electrons from deuterium, with low-momentum protons detected in the backward hemisphere. Restricting the momentum of the spectator protons to ≲100 MeV/c and their angles to ≳100° relative to the momentum transfer allows an interpretation of the process in terms of scattering from nearly on-shell neutrons. The F(2)(n) data collected cover the nucleon-resonance and deep-inelastic regions over a wide range of Bjorken x for 0.65<Q(2)<4.52 GeV(2), with uncertainties from nuclear corrections estimated to be less than a few percent. These measurements provide the first determination of the neutron to proton structure function ratio F(2)(n)/F(2)(p) at 0.2≲x≲0.8 with little uncertainty due to nuclear effects.

Journal: Physical review letters

DOI: 10.1103/PhysRevLett.108.142001