Charge Symmetry Violating Contributions to Neutrino Reactions

Abstract

The NuTeV group has measured charged and neutral current reactions for neutrinos on iron targets. Ratios of these cross sections provide an independent measurement of the Weinberg angle. The NuTeV value for sin^2 theta_W is three standard deviations larger than the value measured in other electroweak processes. By reviewing theoretical estimates of parton charge symmetry violation (CSV), we study CSV contributions to the NuTeV measurement. We conclude that charge symmetry violating effects should remove roughly 30% of the discrepancy between the NuTeV result and other determinations of sin^2 theta_W.

Comments: 15 pages, 2 figures; Fig 2 replaced [CSV distribution calculated at low Q^2, evolved to 20 GeV^2]; table II changed