Search for W Boson Decays to Three Charged Pions


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Sirunyan A., Tumasyan A., Adam W., Ambrogi F., Asilar E., Bergauer T., ...More

Physical Review Letters, vol.122, no.15, 2019 (SCI-Expanded, Scopus) identifier identifier identifier identifier

Abstract

For the first time, a search for the rare decay of the W boson to three charged pions has been performed. Proton-proton collision data recorded by the CMS experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 77.3 fb-1, have been analyzed. No significant excess is observed above the background expectation. An upper limit of 1.01×10-6 is set at 95% confidence level on the branching fraction of the W boson to three charged pions. This provides a strong motivation for theoretical calculations of this branching fraction.