Naslov
Measurement of the Parity-Violating Asymmetry in Inclusive Electroproduction of π- near the Δ0 Resonance

Autori
Androić, Darko ; ... ; Ševa, Tomislav ; ... ; Wood, S.A.

Izvornik
Physical Review Letters (0031-9007) 108 (2012); 122002-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
parity-violating asymmetry; electron scattering; deuterium target

Sažetak
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 +5.2  ppm. The measurement performed in this work leads to Aγ-=-0.36±1.06±0.37±0.03  ppm (where sources of statistical, systematic and theoretical uncertainties are included), which would disfavor enchancements considered by Zhu et al. proportional to Vud/Vus. 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.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

Napomena
G0 Collaboration.

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