NuTeV anomaly, neutrino mixing, and a heavy Higgs boson

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Date
2003-04
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American Physical Society
Abstract

Recent results from the NuTeV experiment at Fermilab and the deviation of the Z invisible width, measured at CERN LEP and the SLAC Linear Collider, from its standard model (SM) prediction suggest the suppression of neutrino-Z couplings. Such suppressions occur naturally in models which mix the neutrinos with heavy gauge singlet states. We postulate a universal suppression of the Znunu couplings by a factor of (1-epsilon) and perform a fit to the Z-pole and NuTeV observables with epsilon and the oblique correction parameters S and T. Compared to a fit with S and T only, the inclusion of epsilon leads to a dramatic improvement in the quality of the fit. The values of S and T preferred by the fit can be obtained within the SM by a simple increase in the Higgs boson mass. However, if the W mass is also included in the fit, a non-zero U parameter becomes necessary which cannot be supplied within the SM. The preferred value of epsilon suggests that the seesaw mechanism may not be the reason why neutrinos are so light.

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Keywords
fermion pair production, supersymmetric standard model, extra, dimensions, sin(2) theta(w), qed corrections, mass, annihilation, oscillation, parameters, calculate, Astronomy & Astrophysics, Physics
Citation
Loinaz, W ; Okamura, N ; Takeuchi, T ; et al., APR 2003. “NuTeV anomaly, neutrino mixing, and a heavy Higgs boson,” PHYSICAL REVIEW D 67(7): 073012. DOI: 10.1103/PhysRevD.67.073012