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 $h\to e\ddot{I}„$, $h\to \hat{I}¼\ddot{I}„$, $b\to s{\ell }^{+}{\ell }^{-}$, the $W$ mass and $R(D^{(\ast )})$ as well as the excess in $t\to b{H}^{+}(130\mathrm{GeV})\to b\overline{b}c$ is possible. While this requires flavour violating couplings, the stringent bounds from e.g. $\hat{I}¼\to e{\hat{I}}^3$, $\ddot{I}„\to \hat{I}¼{\hat{I}}^3$, $B_s-{\bar{B}}_s$ mixing, $b\to s{\hat{I}}^3$, low mass di-jet and $pp\to H^{+}{H}^{-}\to \ddot{I}{„}^{+}\ddot{I}{„}^{-}\hat{I}½\bar{\hat{I}}½$ 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.

10 pages, 3 figures, 1 table, typo corrected, final version