Effective-field theory analysis of the τ − → π − π 0 ν τ decays

J. Miranda (Departamento de Física, Centro de Investigación y de Estudios Avanzados del IPN, Apdo. Postal 14-740, Ciudad de México, 07000, México) ; P. Roig (Departamento de Física, Centro de Investigación y de Estudios Avanzados del IPN, Apdo. Postal 14-740, Ciudad de México, 07000, México)

We perform an effective field theory analysis of the τ − → π − π 0 ν τ decays, that includes the most general interactions between Standard Model fields up to dimension six, assuming left-handed neutrinos. We constrain as much as possible the necessary Standard Model hadronic input using chiral symmetry, dispersion relations, data and asymptotic QCD properties. As a result, we show that it is possible to set precise (competitive with low-energy and LHC measurements) bounds on (non-standard) charged current tensor interactions, finding a very small preference for their presence, according to Belle data. Belle-II near future measurements can thus be very useful in either confirming or further restricting new physics tensor current contributions to these decays. For this, the spectrum in the di-pion invariant mass turns out to be particularly promising. Distributions in the angle defined by the τ − and π − momenta can also be helpful if measured with less than 10% accuracy, both for non-standard scalar and tensor interactions.

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      "title": "Effective-field theory analysis of the \u03c4 \u2212 \u2192 \u03c0 \u2212 \u03c0 0 \u03bd  \u03c4  decays"
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Published on:
07 November 2018
Publisher:
Springer
Published in:
Journal of High Energy Physics , Volume 2018 (2018)
Issue 11
Pages 1-27
DOI:
https://doi.org/10.1007/JHEP11(2018)038
Copyrights:
The Author(s)
Licence:
CC-BY-3.0

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