Target and beam-target spin asymmetries in exclusive pi(+) and pi(-) electroproduction with 1.6-to 5.7-GeV electrons

CLAS Collaboration, P. E. Bosted*, A. S. Biselli, S. Careccia, G. Dodge, R. Fersch, N. Guler, S. E. Kuhn, J. Pierce, Y. Prok, X. Zheng, K. P. Adhikari, D. Adikaram, Z. Akbar, M. J. Amaryan, S. Anefalos Pereira, G. Asryan, H. Avakian, R. A. Badui, J. BallN. A. Baltzell, M. Battaglieri, V. Batourine, I. Bedlinskiy, S. Boiarinov, W. J. Briscoe, S. Bultmann, V. D. Burkert, T. Cao, D. S. Carman, A. Celentano, S. Chandavar, G. Charles, T. Chetry, G. Ciullo, L. Clark, L. Colaneri, P. L. Cole, M. Contalbrigo, O. Cortes, V. Crede, A. D'Angelo, N. Dashyan, R. De Vita, Jamie Fleming, Simon Hughes, G. D. Smith, Ivana Stankovic, D. P. Watts, N. Zachariou, L. Zana

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Beam-target double-spin asymmetries and target single-spin asymmetries in exclusive pi(+) and quasiexclusive pi(-) electroproduction were obtained from scattering of 1.6- to 5.7-GeV longitudinally polarized electrons from longitudinally polarized protons (for pi(+)) and deuterons (for pi(-)) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The kinematic range covered is 1.1 <W <2.6 GeV and 0.05 <Q(2) <5 GeV2, with good angular coverage in the forward hemisphere. The asymmetry results were divided into approximately 40 000 kinematic bins for pi(+) from free protons and 15 000 bins for pi(-) production from bound nucleons in the deuteron. The present results are found to be in reasonable agreement with fits to previous world data for W <1.7 GeV and Q(2) <0.5 GeV2, with discrepancies increasing at higher values of Q(2), especially for W > 1.5 GeV. Very large target-spin asymmetries are observed for W > 1.6 GeV. When combined with cross-section measurements, the present results can provide powerful constraints on nucleon resonance amplitudes at moderate and large values of Q(2), for resonances with masses as high as 2.3 GeV.

Original languageEnglish
Article number055201
Number of pages25
JournalPhysical Review C
Volume94
Issue number5
DOIs
Publication statusPublished - 1 Nov 2016

Keywords / Materials (for Non-textual outputs)

  • CHARGED PIONS
  • DEUTERONS
  • NUCLEON
  • GEV2
  • CLAS

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