A novel probe of the Higgs boson coupling to "charm" and other light quarks

Using the full LHC Run 2 data set with proton-proton collisions at a center-of-mass energy of 13 TeV, Ralf Schmieder, a PhD student at the ETP, has performed the first measurement of a slight difference in the associated production of the Higgs boson with the W boson. This is defined as the difference between the abundances with which positively or negatively charged W bosons have been encountered. Because protons contain more quarks with the flavor "up" than "down", the Standard Model of Particle Physics (SM) predicts a difference of about two. The exact value of this asymmetry depends, among other things, on the as yet unknown couplings of the Higgs boson to the "charm" and to other light quarks. No deviations from the expectation of the SM were observed. However, the presented measurement demonstrates the potential of the applied method when it comes to investigating the couplings of the Higgs boson to very light quarks, which will be difficult to determine otherwise at the LHC. A preliminary publication of the results by the CMS collaboration can be found at this link.