Measurement of the W boson decay branching fraction ratio B(W ->c q)/B(W -> q-bar q') in proton-proton collisions at sqrt(s) = 13 TeV

Babbar, J.; Belforte, S.; Candelise, V.; Casarsa, M.; Cossutti, F.; De Leo, K.; Della Ricca, G.; ET AL (the CMS Collaboration),

doi:10.1016/j.physletb.2025.139754

The most precise measurement to date of the W boson hadronic decay branching fraction ratio 𝑅Wc = ℬ(W → cq)∕ℬ(W →qq′ ) is presented. The measurement is based on a sample of proton-proton collision data from the CERN LHC collected by the CMS experiment at a center-of-mass energy of 13TeVin 2016–2018 with an integrated luminosity of 138fb−1. The large cross section of top quark-antiquark production at the LHC offers a sizable high purity sample of W bosons suitable for this measurement. Events with one charged lepton (electron or muon) and at least four jets, two tagged as bottom quark jets, are analyzed. Charm jets are tagged using the presence of a muon inside the jet. The result, 𝑅Wc =0.489±0.020, is consistent with the standard model prediction and is twice as precise as the current world-average value.

Measurement of the W boson decay branching fraction ratio B(W ->c q)/B(W -> q-bar q') in proton-proton collisions at sqrt(s) = 13 TeV / Babbar, J.; Belforte, S.; Candelise, V.; Casarsa, M.; Cossutti, F.; De Leo, K.; Della Ricca, G.; ET AL (the CMS, Collaboration). - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - STAMPA. - 868:(2025), pp. 139754.1-139754.28. [10.1016/j.physletb.2025.139754]