Accumulating Hints for Flavour Violating Higgses at the Electroweak Scale

Abstract

We show that supplementing the Standard Model by only a second Higgs doublet, a combined explanation of $h\to eτ$, $h\to μτ$, $b\to s \ell^+ \ell^-$, the $W$ mass and $R({D^{(*)}})$ as well as the excess in $t\to bH^+(130\,{\rm GeV})\to b\overline{b}c$ is possible. While this requires flavour violating couplings, the stringent bounds from e.g. $μ\to eγ$, $τ\to μγ$, $B_s-\bar B_s$ mixing, $b\to sγ$, low mass di-jet and $pp\to H^+H^-\to τ^+τ^-ν\barν$ searches can be avoided. However, the model is very constrained, it inevitably predicts a shift in the SM Higgs coupling strength to tau leptons as well as a non-zero $t\to hc$ rate, as indeed preferred by recent measurements. We study three benchmark points providing such a simultaneous explanation and calculate their predictions, including collider signatures which can be tested with upcoming LHC run-3 data.