MEASUREMENT OF THE WEAK NEUTRAL CURRENT VIA NUCLEAR PARITY VIOLATION
Journal or Book Title
PHYSICAL REVIEW D
Present low-energy experiments which detect parity violation in nuclei are analyzed, and a consistent set of weak couplings is extracted. Using symmetries and the quark model, it is shown that a parity-violating weak-neutral-current contribution is required by the data, and we extract values sin2θW=0.0±0.4 or ρ=1.1±0.2, consistent with other determinations. The error quoted is statistical only, and does not include a possibly sizable theoretical uncertainty. On the other hand, if we assume the world-average values for ρ and θW, we can obtain from the data (with minimal quark-model assumptions) the matrix element of an operator which is closely related to operators involved in the so-called ‘‘penguin’’ diagrams of ΔS=1 hyperon decay. The matrix element so obtained is consistent with that calculated in a modified form of the vacuum-saturation technique, and has a magnitude such that the penguin contributions to hyperon decays are moderate but not dominant.
Donoghue, JF and Holstein, BR, "MEASUREMENT OF THE WEAK NEUTRAL CURRENT VIA NUCLEAR PARITY VIOLATION" (1985). PHYSICAL REVIEW D. 202.
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