Searches for lepton-flavour-violating decays of the Higgs boson into e-$\tau$ and $\mu$-$\tau$ in ATLAS

This talk presents direct searches for lepton flavor violation in Higgs boson decays, $H\rightarrow e\tau$ and $H\rightarrow \mu\tau$, performed using data collected with the ATLAS detector at the LHC. The searches are based on a data sample of proton-proton collisions at a center-of-mass energy $\sqrt{s}=13$ TeV, corresponding to an integrated luminosity of 138 fb$^{-1}$. Two background estimation techniques are exploited, one based on Monte Carlo simulations and the other one on data: the former is used to measure the absolute values of the branching ratios, while the latter is particularly sensitive to the difference in branching ratios. Results are presented for the branching ratios B($H\rightarrow e\tau$) and B($H\rightarrow \mu\tau$) obtained from the simultaneous measurement of the $H\rightarrow e\tau$ and $H\rightarrow \mu\tau$ signals.