Limits on Lorentz violation from charged-pion decay

Abstract

Charged-pion decay offers many opportunities to study Lorentz violation. Using an effective field theory approach, we study Lorentz violation in the lepton, W-boson, and quark sectors and derive the differential pion-decay rate, including muon polarization. Using coordinate redefinitions we are able to relate the first-generation quark sector, in which no bounds were previously reported, to the lepton and W-boson sector. This facilitates a tractable calculation, enabling us to place bounds on the level of $10^{-4}$ on first-generation quark parameters. Our expression for the pion-decay rate can be used to constrain Lorentz violation in future experiments.

12 pages, 1 figure, Accepted for publication in Phys. Rev. D

References in corpus (2)

• Matter-gravity couplings and Lorentz violation
• pi/K -> e nu branching ratios to O(e^2 p^4) in Chiral Perturbation Theory

Cited by in corpus (1)

• Testing Lorentz invariance in orbital electron capture