Abstract
Abstract We perform a phenomenological fit to all ATLAS, CMS, CDF and D0 Higgs boson data available after Moriond 2012. We allow all Higgs boson branching fractions, its couplings to standard model particles, as well as to an hypothetical invisible sector to vary freely, and determine their current favourite values. The standard model Higgs boson with a mass 125 GeV correctly predicts the average observed rate and provides an acceptable global fit to data. However, better fits are obtained by non-standard scenarios that reproduce anomalies in the present data (more γγ and less WW signals than expected) such as modified rates of loop processes or partial fermiophobia. We find that present data disfavours Higgs boson invisible decays. We consider implications for the standard model, for supersymmetric and fermiophobic Higgs bosons, for dark matter models, for warped extra-dimensions.
Highlights
Named gluon-gluon fusion, vector-boson fusion (VBF) and associated production with W and Z bosons (Vh)
Because different search categories are sensitive to different Higgs boson couplings, the LHC can study the properties of a Higgs boson with mh ≈ 125 GeV and test if it follows the SM predictions or is affected by new physics
From a theoretical point of view, reconstructing the Higgs boson properties is an important way to address the main issue that LHC can clarify: is there a natural reason behind the the smallness of the weak scale, mh MPl? if the weak scale is naturally small, one expects that the new physics that cuts off the top loop contribution to m2h affects the gg → h and h → γγ rates
Summary
The experimental collaborations measure rates of Higgs boson signals R. In the context of fermiophobic Higgs boson searches, ATLAS measured the pp → hX → γγX rate with a high cut pT h > 40 GeV on the Higgs boson transverse momentum [36] (we are oversimplifying by omitting several secondary issues) This cut allows to suppress the gg → h production process, while keeping most of the signal in the VBF and associate production mechanisms. To see how much gg → h is suppressed we allowed for additional QCD jets performing simulations with the Pythia [37] and MadGraph [38] codes We find that this experimental result can be re-interpreted in a general context as a measurement of [0.3σ(pp → h) + σ(pp → W h, Zh, jjh)] × BR(h → γγ),. The average rate of fermionic channels lies along the SM prediction; here the new Tevatron combination for h → bb plays an important role
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