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Modified Paschos-Wolfenstein relation and extraction of weak mixing angle sin^2 theta_W

S. Kumano
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Abstract

The NuTeV collaboration reported anomalously large weak mixing angle sin^2 theta_W in comparison with the standard model prediction. Neutrino and antineutrino charged- and neutral-current events are analyzed for extracting sin^2 theta_W. Although the Paschos-Wolfenstein relation is not directly used in the analysis, it plays an important role in the determination. Noting that the target nucleus, iron, is not an isoscalar nucleus, we derive a leading-order expression for a modified Paschos-Wolfenstein relation for nuclei, which may have neutron excess. Then, using charge and baryon-number conservations for nuclei, we discuss a nuclear correction in the sin^2 theta_W determination. It is noteworthy that nuclear modifications are different between valence up- and down-quark distributions. We show this difference effect on the NuTeV sin^2 theta_W deviation.

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S. Kumano. 2002-11-28. Modified Paschos-Wolfenstein relation and extraction of weak mixing angle sin^2 theta_W. https://doi.org/10.1103/physrevd.66.111301

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