Measurement of the Neutron F-2 Structure Function via Spectator Tagging with CLAS

CLAS Collaboration, N. Baillie, S. Tkachenko, J. Zhang, P. Bosted, S. Bueltmann, M. E. Christy, H. Fenker, K. A. Griffioen, C. E. Keppel, S. E. Kuhn, W. Melnitchouk, V. Tvaskis, K. P. Adhikari, D. Adikaram, M. Aghasyan, M. J. Amaryan, M. Anghinolfi, J. Arrington, H. AvakianH. Baghdasaryan, M. Battaglieri, A. S. Biselli, D. Branford, W. J. Briscoe, W. K. Brooks, V. D. Burkert, D. S. Carman, A. Celentano, S. Chandavar, G. Charles, P. L. Cole, M. Contalbrigo, V. Crede, A. D'Angelo, A. Daniel, N. Dashyan, R. De Vita, E. De Sanctis, A. Deur, B. Dey, C. Djalali, G. Dodge, J. Domingo, D. Doughty, R. Dupre, D. Dutta, R. Ent, H. Egiyan, A. El Alaoui, D. P. Watts

Research output: Contribution to journalArticlepeer-review


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 less than or similar to 100 MeV/c and their angles to greater than or similar to 100 degrees 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 GeV2, 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 less than or similar to x less than or similar to 0.8 with little uncertainty due to nuclear effects.

Original languageEnglish
Article number142001
Pages (from-to)-
Number of pages6
JournalPhysical Review Letters
Issue number14
Publication statusPublished - 6 Apr 2012

Cite this