Measurement of the parity-violating asymmetry in inclusive electroproduction of π - Near the Δ0 resonance

  • D. Androić
  • , D. S. Armstrong
  • , J. Arvieux
  • , S. L. Bailey
  • , D. H. Beck
  • , E. J. Beise
  • , J. Benesch
  • , F. Benmokhtar
  • , L. Bimbot
  • , J. Birchall
  • , P. Bosted
  • , H. Breuer
  • , C. L. Capuano
  • , Y. C. Chao
  • , A. Coppens
  • , C. A. Davis
  • , C. Ellis
  • , G. Flores
  • , G. Franklin
  • , C. Furget
  • D. Gaskell, M. T.W. Gericke, J. Grames, G. Guillard, J. Hansknecht, T. Horn, M. K. Jones, P. M. King, W. Korsch, S. Kox, L. Lee, J. Liu, A. Lung, J. Mammei, J. W. Martin, R. D. McKeown, A. Micherdzinska, M. Mihovilovic, H. Mkrtchyan, M. Muether, S. A. Page, V. Papavassiliou, S. F. Pate, S. K. Phillips, P. Pillot, M. L. Pitt, M. Poelker, B. Quinn, W. D. Ramsay, J. S. Real, J. Roche, P. Roos, J. Schaub, T. Seva, N. Simicevic, G. R. Smith, D. T. Spayde, M. Stutzman, R. Suleiman, V. Tadevosyan, W. T.H. Van Oers, M. Versteegen, E. Voutier, W. Vulcan, S. P. Wells, S. E. Williamson, S. A. Wood

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

The parity-violating (PV) asymmetry of inclusive π - production in electron scattering from a liquid deuterium target was measured at backward angles. The measurement was conducted as a part of the G0 experiment, at a beam energy of 360 MeV. The physics process dominating pion production for these kinematics is quasifree photoproduction off the neutron via the Δ0 resonance. In the context of heavy-baryon chiral perturbation theory, this asymmetry is related to a low-energy constant dΔ- that characterizes the parity-violating γNΔ coupling. Zhu et al. calculated dΔ- in a model benchmarked by the large asymmetries seen in hyperon weak radiative decays, and predicted potentially large asymmetries for this process, ranging from Aγ-=-5.2 to +5.2ppm. The measurement performed in this work leads to Aγ-=-0.36±1.06±0.37±0.03ppm (where sources of statistical, systematic and theoretical uncertainties are included), which would disfavor enchancements considered by Zhu et al. proportional to V ud/V us. The measurement is part of a program of inelastic scattering measurements that were conducted by the G0 experiment, seeking to determine the N-Δ axial transition form factors using PV electron scattering.

Original languageEnglish
Article number122002
JournalPhysical Review Letters
Volume108
Issue number12
DOIs
StatePublished - Mar 20 2012

Funding

FundersFunder number
National Science Foundation Arctic Social Science Program1019521
National Science Foundation Arctic Social Science Program

    ASJC Scopus subject areas

    • General Physics and Astronomy

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