Cornering dimension-6 HV V interactions at high energy LHC: the role of event ratios

Abstract

Abstract:We suggest a way of improving the probes on dimension-6 CP-conserving HV V interactions (V = W , Z, γ), from the LHC data on the Higgs boson to be available in the 14 TeV run with an integrated luminosity of 3000 fb −1 . We find that the ratios of total rates in different channels can be quite useful in this respect. This includes ratios of event rates in (a) different final states for the Higgs produced by the same production mechanism, and (b) the same final state from two different production modes. While most theoretical uncertainties cancel in the former, the latter helps in the case of those operators which shift the numerator and denominator in opposite directions. Our analysis, incorporating theoretical, systematic and statistical uncertain, leads to projected limits that are better than the strongest ones obtained so far from precision electroweak as well as LHC Higgs data. Moreover, values of the coefficients of the dimension-6 operators, which are allowed in disjoint intervals, can have their ranges narrowed down substantially in our approach.

DistinguishingCP-odd couplings of the Higgs boson to weak boson pairs

“…As for the CP-odd terms, we take the benchmark point asf B =f W = −30.77 such thatC ZZh = 40.0 andC γZh = 0.0 [ Table 1 ]. Both of these benchmarks are consistent with existing constraints [65,75]. The histograms in the two figures are indicative of the induced asymmetry in the distributions for both O 1 and O 2 when the CP-violating coupling is turned on.…”

“…1 and 2 histograms of the differential cross section distributions corresponding to observables O 1 and O 2 respectively. In both the figures, to tune in the CP-even Lagrangian, we have taken the benchmark value f W W = −3.0 [75] which corresponds to C ZZh = 4.62 and C γZh = 2.53. As for the CP-odd terms, we take the benchmark point asf B =f W = −30.77 such thatC ZZh = 40.0 andC γZh = 0.0 [ Table 1 ].…”

The Higgs legacy of the LHC Run I

“…The second question has been tackled by Higgs specialized tools, for example presented in refs. [19][20][21][22][23][24][25][26][27][28][29][30]. A shift from the analysis of Higgs couplings based on total rates to an effective field theory of the Higgs sector is the appropriate step to include kinematic distributions in the Higgs fit.…”

“…These operators can be classified by their dimension. For example for the Higgs coupling to W and Z bosons this question has been studied independently of the coupling strength [19][20][21][22][23][24][25][26][27][28][29][30][63][64][65][66][67].…”

Extended scalar sectors, effective operators and observed data

“…The role and usefulness of higher-dimensional operators in dealing with unknown physics in Higgs phenomenology have already been discussed in a large body of works found in the literature [2][3][4][5][6][7][8][9][10][11][12][13]17]. For example, in [17], ways towards improved under-standing on the dimension-6 hV V operators in the high luminosity run of the LHC have been suggested. The utility of various ratios of signal strengths in different channels has figured in discussions found there.…”