Searching for low-mass resonances decaying into <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>W</mml:mi></mml:math> bosons

Abstract

In recent years, several hints for new scalar particles have been observed by the Large Hadron Collider at CERN. In this context, we recast and combine the CMS and ATLAS analyses of the Standard Model Higgs boson decaying to a pair of $W$ bosons in order to search for low-mass resonances. We provide limits on the corresponding cross section assuming direct production via gluon fusion. For the whole range of masses, we consider (90--200 GeV); the observed limit on the cross section turns out to be weaker than the expected one. Furthermore, at $\ensuremath{\approx}95\text{ }\text{ }\mathrm{GeV}$, the limit is weakest, and a new scalar decaying into a pair of $W$ bosons (which subsequently decay leptonically) with a cross section $\ensuremath{\approx}0.5\text{ }\text{ }\mathrm{pb}$ is preferred over the Standard Model hypothesis by $\ensuremath{\gtrsim}2.5\ensuremath{\sigma}$. In light of the previously existing excesses in other channels at similar masses, this strengthens the case for such a new Higgs boson and gives room for the scalar candidate at 95 GeV decaying into $W$ bosons.