Hidden Higgs Boson at the LHC and Light Dark Matter Searches

TL;DR

This paper explores how an invisible Higgs decay into light dark matter particles could explain the absence of Higgs signals in certain mass ranges at the LHC, and discusses implications for dark matter detection.

Contribution

It introduces a simple extension of the Standard Model with a scalar dark matter candidate that can cause the Higgs to decay invisibly, affecting search strategies and experimental constraints.

Findings

Invisible Higgs decays can significantly reduce the excluded mass regions.

The model aligns with recent dark matter hints from CRESST-II.

Future LHC and direct detection experiments can test this scenario.

Abstract

Recent LHC searches have not found a clear signal of the Higgs boson h of the standard model (SM) with three or four families in the mass range m_h = 120-600 GeV. If the Higgs had an unexpectedly large invisible branching ratio, the excluded m_h regions would shrink. This can be realized in the simplest weakly interacting massive particle dark matter (DM) model, which is the SM plus a real gauge-singlet scalar field D as the DM, via the invisible mode h -> DD. Current data allow this decay to occur for D-mass values near, but below, m_h/2 and those compatible with the light DM hypothesis. For such D masses, h -> DD can dominate the Higgs width depending on m_h, and thus sizable portions of the m_h exclusion zones in the SM with three or four families may be recovered. Increased luminosity at the LHC may even reveal a Higgs having SM-like visible decays still hiding in the presently disallowed regions. The model also accommodates well the new possible DM hints from CRESST-II and will be further tested by improved data from future DM direct searches.