Test of isospin symmetry via low-energy 1H(pi{-},pi{0})n charge exchange.
We report measurements of the pi;{-}p-->pi;{0}n differential cross sections at six momenta (104-143 MeV/c) and four angles (0 degrees -40 degrees ) by detection of gamma-ray pairs from pi;{0}-->gammagamma decays using a photon-pair spectrometer at TRIUMF. This kinematic region exhibits a vanishing zero-degree cross section from destructive interference between s and p waves, thus yielding special sensitivity to pion-nucleon dynamics. Our data and previous data do not agree, with important implications for earlier claims of large isospin-violating effects.
University of Kentucky, Lexington, Kentucky 40506, USA.
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Jia
T P
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Gorringe
M D
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Hasinoff
M A
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Kovash
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Ojha
M M
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Pavan
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Tripathi
P A
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Zołnierczuk