2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/38373A sample of 400 $B^0_d/\bar{B}{^0_d} \to J/ψK^0_s$ decays collected in $\bar{p}p$ collisions by the CDF detector is used to directly measure the CP-violation parameter $\sin(2β)$. We find $\sin(2β) = 0.79 ^{+0.41}_{-0.44}$,favoring the standard model expectation of a large $CP$ violation in this $B^0$ decay mode.4 Pages; Contribution to The International Europhysics Conference on High-Energy Physics (EPS-HEP 99), Tampere, Finland, July 15-21, 1999High Energy Physics - Experimenttext