Search for W Boson Decays to Three Charged Pions

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American Physical Society

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\text{}\text{}{\mathrm{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.

PAIR PRODUCTION, Physics, Multidisciplinary, Physics
Sirunyan, A. M., Tumasyan, A., Adam, W., Ambrogi, F., Asilar, E., Bergauer, T., Brandstetter, J., Dragicevic, M., Erö, J., Escalante Del Valle, A., Flechl, M., Frühwirth, R., Ghete, V. M., Hrubec, J., Jeitler, M., Krammer, N., Krätschmer, I., Liko, D., … Madlener, T. (2019). Search for W Boson Decays to Three Charged Pions. In Physical Review Letters (Vol. 122, Issue 15). American Physical Society (APS).