Charge symmetry breaking in n p --> d pi^0

Abstract

The forward--backward asymmetry in n p --> d pi^0, which must be zero in the center-of-mass system if charge symmetry is respected, has been measured to be [17.2 +/- 8 (stat) +/- 5.5 (sys)] * 10^{-4}, at an incident neutron energy of 279.5 MeV. This charge symmetry breaking observable was extracted by fitting the data with GEANT-based simulations and is compared to recent chiral effective field theory calculations, with implications regarding the value of the u d quark mass difference.

arXiv comment5 pages, 2 figures, submitted to Phys Rev Let

References in corpus (2)

• Observation of the Charge Symmetry Breaking d + d -> 4He + pi0 Reaction Near Threshold
• Charge Symmetry Violation in $pn\to d{\pi }^0$ as a Test of Chiral Effective Field Theory

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