Nondecoupling supersymmetry and an $L_\mu - L_\tau$ gauge boson at Belle-II

by Heerak Banerjee (Indian Association for the Cultivation of Science)

Wednesday 30 Oct 2019, 16:00 → 17:30 Europe/Rome

Aula Conversi (Dip. di Fisica - Edificio G. Marconi)

We find that the radiative contribution of charged sleptons to the $\gamma - Z^\prime$ kinetic mixing is nondecoupling in the presence of a gauged $U(1)_{L_\mu-L_\tau}$ symmetry, depending logarithmically on the ratio (r) of stau to smuon masses. The signal process, $e^+ e^- \rightarrow \gamma Z^\prime \rightarrow \gamma + E_T^{\rm miss}$ at Belle-II arises through kinetic mixing in this case. Considering the constraints on gauged $U(1)_{L_\mu-L_\tau}$  models, we show that any significant excess in all but the highest photon energy bin would be a smoking gun for such heavy scalar fields in SUSY coupling to $Z^\prime$. This process can probe large swathes of the r vs $g_X$ parameter space as well as the $M_{Z^{\prime}}-g_X$ parameter space still allowed in gauged $U(1)_{L_\mu-L_\tau}$ models for superheavy sparticles.