Hadronic τ Decays as New Physics Probes in the LHC Era
Résumé
We analyze the sensitivity of hadronic τ decays to nonstandard interactions within the model-independent framework of the standard model effective field theory. Both exclusive and inclusive decays are studied, using the latest lattice data and QCD dispersion relations. We show that there are enough theoretically clean channels to disentangle all the effective couplings contributing to these decays, with the τ→ππντ channel representing an unexpected powerful new physics probe. We find that the ratios of nonstandard couplings to the Fermi constant are bound at the subpercent level. These bounds are complementary to the ones from electroweak precision observables and pp→τντ measurements at the LHC. The combination of τ decay and LHC data puts tighter constraints on lepton universality violation in the gauge boson-lepton vertex corrections.
Mots clés
Elementary Particles and Fields
tau: hadronic decay
lepton: universality: violation
correction: vertex
weak interaction: coupling constant
CERN LHC Coll
new physics
electroweak interaction
quantum chromodynamics
effective field theory
dispersion relation
sensitivity
lattice field theory
data analysis method
tau --> pi pi neutrino/tau