Status of invisible Higgs decays

TL;DR

This paper assesses how LHC and Tevatron data constrain invisible decays of a 125 GeV Higgs boson, exploring various coupling scenarios and their implications for dark matter and future searches.

Contribution

It provides a comprehensive global fit analysis of invisible Higgs decay constraints under different coupling assumptions using collider data.

Findings

Invisible decay rates up to 23%, 61%, and 88% are consistent with data at 95% CL for different models.

Limiting vector boson coupling reduces the invisible decay allowance to 56%.

Sign constraints on quark couplings allow up to 36% invisible decay at 95% CL.

Abstract

We analyze the extent to which the LHC and Tevatron results as of the end of 2012 constrain invisible (or undetected) decays of the Higgs boson-like state at ~ 125 GeV. To this end we perform global fits for several cases: 1) a Higgs boson with Standard Model (SM) couplings but additional invisible decay modes; 2) SM couplings to fermions and vector bosons, but allowing for additional new particles modifying the effective Higgs couplings to gluons and photons; 3) no new particles in the loops but tree-level Higgs couplings to the up-quarks, down-quarks and vector bosons, relative to the SM, treated as free parameters. We find that in the three cases invisible decay rates of 23%, 61%, 88%, respectively, are consistent with current data at 95% confidence level (CL). Limiting the coupling to vector bosons, CV, to CV < 1 in case 3) reduces the allowed invisible branching ratio to 56% at 95% CL. Requiring in addition that the Higgs couplings to quarks have the same sign as in the SM, an invisible rate of up to 36% is allowed at 95% CL. We also discuss direct probes of invisible Higgs decays, as well as the interplay with dark matter searches.