Higgs precision (Higgcision) era begins

Abstract

After the discovery of the Higgs boson at the LHC, it is natural to start the research program on the precision study of the Higgs-boson couplings to various standard model (SM) particles. We provide a generic framework for the deviations of the couplings from their SM values by introducing a number of parameters. We show that a large number of models beyond the SM can be covered, including two-Higgs-doublet models, supersymmetric models, little-Higgs models, extended Higgs sectors with singlets, and fourth generation models. We perform global fits to the most updated data from CMS, ATLAS, and Tevatron under various initial conditions of the parameter set. In particular, we have made explicit comparisons between the fitting results before and after the Moriond 2013 meetings. Highlights of the results include: (i) the nonstandard decay branching ratio of the Higgs boson is less than 22%; (ii) the most efficient way to achieve the best fit for the data before the Moriond update is to introduce additional particle contributions to the triangularloop functions of Hγγ and Hgg vertices; (iii) the 1σ allowed range of the relative coupling of HV V is 1.01 +0.13 −0.14 , which means that the electroweak-symmetry breaking contribution from the observed Higgs boson leaves only a small room for other Higgs bosons; (iv) the current data do not rule out pseudoscalar couplings nor pseudoscalar contributions to the Hγγ and Hgg vertices; and (v) the SM Higgs boson provides the best fit to all the current Higgs data.

Probing the Standard Model with Higgs signal rates from the Tevatron, the LHC and a future ILC

“…[8] concerning the discussion of a more general framework based on suitable effective Lagrangians. The coupling scale factors have been analyzed by the experimental collaborations [3,5] as well as in further phenomenological studies where Higgs coupling fits have been carried out [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. The results of those analyses show no significant deviations from SM Higgs couplings.…”

“…In this section we study to what extent the specific implementation of the χ 2 evaluation in HiggsSignals impacts the P-value calculation. This is also of interest for other implementations of χ 2 tests against Higgs mass and rate measurements [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28], which employ different levels of detail concerning the implementation - of uncertainties (correlated/uncorrelated, relative/absolute, symmetric/asymmetric, etc.). In order to evaluate the impact of the calculation of uncertainties and correlations on the χ 2 , we investigate the P-value of a SM-like Higgs boson modified by a global scale parameter κ.…”

Higgs phenomenology in the Minimal Dilaton Model after Run I of the LHC

“…Since the first hint of the Higgs-like boson at the LHC was uncovered at the end of 2011, the compatibility of the dilaton with the data has been extensively discussed [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. For example, in [23][24][25][26][27][28][29] the traditional dilaton models were compared with models including Higgs boson, and the techni-dilaton was shown to be able to explain the signals well [30][31][32][33][34][35]. The Higgs-dilaton was also used to solve cosmological problems such as inflation and dark energy [36][37][38][39][40].…”

“…Detailed studies indicate that if h instead of s corresponds to the newly discovered boson, a much lower χ 2 can be obtained in the fits to the Higgs data. So in our discussion we fix m h = 125.6 GeV which is the combined mass value of the two collaborations [27][28][29]. As for the potential, it is more convenient to use f , v, θ S , m h and m s as input parameters.…”

Invisible Higgs decay in a supersymmetric inverse seesaw model with light sneutrino dark matter

“…A precise determination of the discovered Higgs boson characteristics will be crucial in resolving some of the outstanding issues of the SM, and in particular, understanding the mechanism of electroweak symmetry breaking and its relationship to the BSM. The experimental results so far [3][4][5][6] show no significant deviation from the SM Higgs sector expectations, and already put severe constraints on various new physics models (see, for instance, [7][8][9][10][11][12][13][14][15]). However, they still do not exclude the possibility of a non-standard Higgs boson.…”