Bottom quark electroweak dipole moments at a high-energy $\mu-$collider

Abstract

We study the sensitivity of a high-energy $\mu-$collider with center of mass energy in the multi--TeV range in testing electroweak dipole interactions of the $b-$quark. We parametrize the relevant deformations in the language of the Standard Model effective field theory, where the dominant modifications arise at the $d=6$ level. We analyse $\mu^+ \mu^- \to b \bar b$ and $\mu^+ \mu^- \to b \bar b h$ scatterings, performing a study at the level of a fast detector simulation. Owing the chiral structure of the dipole interaction, the study of the $\mu^+ \mu^- \to b \bar b h$ process allows to enforce the stronger bounds on the Wilson coefficients of the $d=6$ operators. The limits that can be obtained surpass present and future bounds from EW precision measurements also improving upon the ones arising from the measurement of the $\Delta F=1$ transitions $B\to X_s\gamma$.