CP violation and determination of the $bs$ "flat" unitarity triangle at FCCee

Abstract

We investigate the sensitivity with which two angles of the "flat" unitarity triangle, defined by $V_{ub}^{\ast }{V}_{us}+V_{cb}^{\ast }{V}_{cs}+V_{tb}^{\ast }{V}_{ts}=0$, can possibly be measured directly at FCCee. We show that the measured errors on the angle ${\alpha }_s=\arg (-V_{ub}^{\ast }{V}_{us}/V_{tb}^{\ast }{V}_{ts})$ and ${\beta }_s=\arg (-V_{tb}^{\ast }{V}_{ts}/V_{cb}^{\ast }{V}_{cs})$ should be better than $0.4^{\circ }$ and $0.035^{\circ }$, respectively. These measurements, combined with the measurement of the 3rd angle ${\gamma }_s=\arg (-V_{cb}^{\ast }{V}_{cs}/V_{ub}^{\ast }{V}_{us})$, discussed in a different paper, will contribute to probe further the consistency of the CP sector of the Standard Model with unprecedented level of accuracy.

Comments: 27 pages, 24 figures