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An Effective Field Theory Calculation of the Parity Violating Asymmetry in n+p -> d+gamma

David B. Kaplan·Martin J. Savage·Roxanne P. Springer·Mark B. Wise
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Abstract

Weak interactions are expected to induce a parity violating pion-nucleon coupling, h_{πNN}^{(1)}. This coupling should be measurable in a proposed experiment to study the parity violating asymmetry A_γin the process \vec n + p \to d+γ. We compute the leading dependence of A_γon the coupling h_{πNN}^{(1)} using recently developed effective field theory techniques and find an asymmetry of A_γ= +0.17 h_{πNN}^{(1)} at leading order. This asymmetry has the opposite sign to that given by Desplanques, Donoghue and Holstein.

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David B. Kaplan, Martin J. Savage, Roxanne P. Springer, Mark B. Wise. 1998-07-30. An Effective Field Theory Calculation of the Parity Violating Asymmetry in n+p -> d+gamma. https://doi.org/10.1016/s0370-2693(99)00032-5

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