New Higgses at the Electroweak Scale and Differential $t\bar t$ Distributions (2405.15933v1)

Abstract: Indications for new Higgs bosons at 95\,GeV and 152\,GeV with significance of 3.8$\sigma$ and $4.3\sigma$, respectively, have been obtained. While the former contains the inclusive $\gamma\gamma$ channel, the latter is obtained by combining several modes of associated di-photon production, i.e. $\gamma\gamma+X$ with $X=\ell,\,\ell b,\,{\rm MET},\,\tau,\,...$, within the $\Delta$SM (the Standard Model extended by a real triplet). Such a triplet predicts a positive definite shift in the $W$ mass, in agreement with the current global electroweak fit, and its neutral component decays dominantly to $W$ bosons (for small mixing angles). This offers a connection to $t\bar t$ differential distributions whose experimental signature is $WW b\bar b$: A simplified model with a new scalar $H$, produced via gluon fusion and decaying to $S$ and $S^\prime$ with subsequent (dominant) decays to $WW$ and $b\bar b$, respectively, has the same final state. In fact, adding this new physics polution to the Standard Model describes the leptonic $t\bar t$ distributions better by at least $5.8\sigma$. Furthermore, assuming that $S^\prime$ is an $SU(2)_L$ singlet, the resulting di-photon signal strength is compatible with the 95\,GeV $\gamma\gamma$ measurements. A possible UV completion of this simplified model is the $\Delta$2HDMS, i.e. a 2HDM supplemented with a singlet and a real triplet, which can successfully accommodate electroweak scale Baryogenesis.