Measurement of the CP-violation parameter sin(2beta) in B0 to J/psi-Kshort decays

Abstract

A sample of 400 $B_d^0/\bar{B}{}_d^0\to J/\ddot{I}ˆK_s^0$ decays collected in $\bar{p}p$ collisions by the CDF detector is used to directly measure the CP-violation parameter $\sin (2{\hat{I}}^2)$. We find $\sin (2{\hat{I}}^2)=0.79_{-0.44}^{+0.41}$,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, 1999