Combined measurements of Higgs boson couplings in proton–proton collisions at $$\sqrt{s}=13\,\text {Te}\text {V} $$

Abstract

Combined measurements of the production and decay rates of the Higgs boson, as well as its couplings to vector bosons and fermions, are presented. The analysis uses the LHC proton–proton collision data set recorded with the CMS detector in 2016 at , corresponding to an integrated luminosity of 35.9 . The combination is based on analyses targeting the five main Higgs boson production mechanisms (gluon fusion, vector boson fusion, and associated production with a or boson, or a top quark-antiquark pair) and the following decay modes: , , , , , and . Searches for invisible Higgs boson decays are also considered. The best-fit ratio of the signal yield to the standard model expectation is measured to be , assuming a Higgs boson mass of . Additional results are given for various assumptions on the scaling behavior of the production and decay modes, including generic parametrizations based on ratios of cross sections and branching fractions or couplings. The results are compatible with the standard model predictions in all parametrizations considered. In addition, constraints are placed on various two Higgs doublet models.

Dynamical Higgs field alignment in the NMSSM

“…Inspection of Fig. 4 shows that the deviation of the parameter |η| is below 0.1 for the majority of points, restricting the deviations of all couplings to values below ten percent, in agreement with current experimental observations [51][52][53] (in this work, we shall not consider the region in which the bottom Yukawa coupling acquires a wrong sign, η 2, which can also be achieved within the NMSSM for heavy singlets [54]). The points on the extreme ends of the tan β region reach larger values of |η|, but do not exceed a deviation of 0.16.…”

NNLO QCD + NLO EW with Matrix+OpenLoops: precise predictions for vector-boson pair production

“…Since this happens only when moving from LO to NLO QCD, higher-order QCD corrections beyond NLO are free from further giant K-factors. 5 Note also that the availability of NNLO QCD corrections makes it possible to verify the stability of the perturbative expansion beyond NLO and to arrive at reliable QCD predictions for observables that feature giant K-factors. 5 Here, we assume that in diboson production at the scale Q M W at least one vector boson with p T, For what concerns the combination of QCD and EW corrections, the presence of giant K-factors raises more serious issues.…”

“…5 Note also that the availability of NNLO QCD corrections makes it possible to verify the stability of the perturbative expansion beyond NLO and to arrive at reliable QCD predictions for observables that feature giant K-factors. 5 Here, we assume that in diboson production at the scale Q M W at least one vector boson with p T, For what concerns the combination of QCD and EW corrections, the presence of giant K-factors raises more serious issues. In particular, the fact that in the relevant high-p T regions the NLO QCD and NLO EW corrections are both strongly enhanced implies sizeable theoretical uncertainties from large unknown mixed QCD-EW NNLO effects.…”

“…In particular, due to the high sensitivity to anomalous trilinear couplings, differential measurements at high transverse momenta probe the gauge symmetry structure of EW interactions and provide an excellent chance to detect indirect effects of physics beyond the Standard Model (BSM). Diboson final states are widely studied also in the context of direct BSM searches and in Higgs-boson measurements, where they are non-trivial irreducible backgrounds, as, for example, in the H → W + W − and H → ZZ analyses [1][2][3][4][5][6][7][8]. The increasing level of precision of experimental measurements calls for continuous improvements in the theoretical description of diboson production at the LHC.…”

Dark origin of the quark flavor hierarchy and mixing

“…The origin of flavor hierarchy, reflected in the elementary fermion mass spectrum, remains one of the big conundrums of Nature. The precise LHC measurements of the Higgs boson couplings to gauge bosons and third generation fermions strongly support the Standard Model (SM) mechanism of fermion mass generation, based on the Higgs Yukawa couplings and the electroweak symmetry breaking (EWSM) [1,2,3]. The SM, however, does not shine any light on the puzzle related to the observed span of Yukawa couplings, should this be related to an unknown underlying mechanism rather than the outcome of free parameters not regulated by any symmetry.…”