Probing the neutrino mass through semileptonic meson decays

Authors:
  • DBDamir Bečirević
    Damir Bečirević
  • CCClaire Chevallier
    Claire Chevallier
  • SFSvjetlana Faifer
    Svjetlana Faifer
  • NKNejc Košnik
    Nejc Košnik
  • LPLovre Pavičić
    Lovre Pavičić
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Abstract
We argue that a detailed analysis of semileptonic decays can test the possibility of a massive neutrino. The key observable, related to the forward-backward asymmetry, is exactly zero for a massless neutrino but becomes non-zero if the neutral lepton is heavy and interacts with Standard Model fields via left-handed operators. For right-handed interactions, this quantity differs significantly from zero even for a massless right-handed neutrino. We demonstrate this explicitly using the example of a pseudoscalar meson decaying into another pseudoscalar meson. A similar discussion applies to decays into a vector meson, with an additional subtlety addressed in this work.