Invisible Higgs decay with B\to K\nu\bar{\nu} constraint

TL;DR

This paper uses rare B decay measurements to constrain the invisible decay of the Higgs into light singlet particles, revealing potential deviations from standard model predictions and implications for cosmology.

Contribution

It introduces a novel method to bound Higgs invisible decays via B o K uar{ u} constraints, linking low-energy experiments to Higgs property measurements.

Findings

Upper bound on Higgs coupling to light singlet S from B decay data.

Invisible Higgs decay width comparable to standard decay modes.

Implications for Higgs detection and cosmological models.

Abstract

If the Higgs boson were the only particle within the LHC accessible range, precision measurement of the Higgs's properties would play a unique role in studying electroweak symmetry breaking as well as possible new physics. We try to use low energy experiments such as rare B decay to constrain a challenging decay mode of Higgs, in which a Higgs decays to a pair of light (\approx 1 \sim 2 GeV) SM singlet S and becomes invisible. By using the current experimental bound of rare decay B\to K\nu\bar{\nu} and computing the contribution of B\to K SS to (the) B\to K+\cancel{E}, we obtain an upper bound on the Higgs coupling to such light singlet. It is interesting that the partial width of the invisible decay mode h\to SS by taking the upper bound value of coupling is at a comparable level with h\to WW/ZZ or WW^(*) decay modes, making the Higgs identifiable but with a different predicted decay BR from the standard model Higgs decay. It will then have an impact on precision measurement of the Higgs's properties. We also study the implication for cosmology from such a light singlet and propose a solution to the potential problem.