학술논문
Exclusive $\pi^+$ electroproduction off the proton from low to high -t
Document Type
Working Paper
Author
Basnet, S.; Huber, G. M.; Li, W. B.; Blok, H. P.; Gaskell, D.; Horn, T.; Aniol, K.; Arrington, J.; Beise, E. J.; Boeglin, W.; Brash, E. J.; Breuer, H.; Chang, C. C.; Christy, M. E.; Ent, R.; Gibson, E.; Holt, R. J.; Jin, S.; Jones, M. K.; Keppel, C. E.; Kim, W.; King, P. M.; Kovaltchouk, V.; Liu, J.; Lolos, G. J.; Mack, D. J.; Margaziotis, D. J.; Markowitz, P.; Matsumura, A.; Meekins, D.; Miyoshi, T.; Mkrtchyan, H.; Niculescu, I.; Okayasu, Y.; Pentchev, L.; Perdrisat, C.; Potterveld, D.; Punjabi, V.; Reimer, P.; Reinhold, J.; Roche, J.; Sarty, A.; Smith, G. R.; Tadevosyan, V.; Tang, L. G.; Tvaskis, V.; Volmer, J.; Vulcan, W.; Warren, G.; Wood, S. A.; Xu, C.; Zheng, X.
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Abstract
Background: Measurements of exclusive meson production are a useful tool in the study of hadronic structure. In particular, one can discern the relevant degrees of freedom at different distance scales through these studies. Purpose: To study the transition between non-perturbative and perturbative Quantum Chromodyanmics as the square of four momentum transfer to the struck proton, -t, is increased. Method: Cross sections for the $^1$H(e,e'$\pi^+$)n reaction were measured over the -t range of 0.272 to 2.127 GeV$^2$ with limited azimuthal coverage at fixed beam energy of 4.709 GeV, Q$^2$ of 2.4 GeV$^2$ and W of 2.0 GeV at the Thomas Jefferson National Accelerator Facility (JLab) Hall C. Results: The -t dependence of the measured $\pi^+$ electroproduction cross section generally agrees with prior data from JLab Halls B and C. The data are consistent with a Regge amplitude based theoretical model, but show poor agreement with a Generalized Parton Distribution (GPD) based model. Conclusion: The agreement of cross sections with prior data implies small contribution from the interference terms, and the confirmation of the change in t-slopes between the low and high -t regions previously observed in photoproduction indicates the changing nature of the electroproduction reaction in our kinematic regime.
Comment: 9 pages, 5 figures Physical Review C, in press
Comment: 9 pages, 5 figures Physical Review C, in press