2002/06/30 by Deirdre Black, Tao Han, Hong-Jian He +1 · 1 citation
Physics and Astronomy · #Dark Matter and Cosmic Phenomena #Neutrino Physics Research #Particle physics theoretical and experimental studies #hep-ex #hep-ph #nucl-ex
paper · pdf · doi:10.1103/physrevd.66.053002
published as Phys.Rev.D66:053002,2002 · 34pp. Final version in Phys.Rev.D (refs added, minor rewording, RevTex4)
arxiv created 2002/07/16 · openalex publication_date 2002/09/13 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Motivated by the recent strong experimental evidence of large \ensuremathν_\ensuremathμ\ensuremath-\ensuremathν_\ensuremathτ neutrino mixing, we explore current bounds on the analogous mixing in the charged lepton sector. We present a general formalism for dimension-6 fermionic effective operators involving \ensuremathτ\ensuremath-\ensuremathμ mixing with a typical Lorentz structure (\ensuremathμ\ensuremathΓ\ensuremathτ)(q^\ensuremathα\ensuremathΓq^\ensuremathβ), and discuss their relationship to the standard model gauge symmetry and the underlying flavor dynamics. We derive the low-energy constraints on the new physics scale associated with each operator, mostly from current experimental bounds on rare decay processes of \ensuremathτ, hadrons or heavy quarks. For operators involving at least one light quark (u,d,s), these constraints typically give a bound on the new physics scale of a few TeV or higher. Those operators with two heavy quarks turn out to be more weakly constrained at the present, giving bounds of a few hundred GeV. A few scalar and pseudoscalar operators are free from all current experimental constraints.