${\rm Y}(4S)\to B^0\overline{B^0}\gamma$ Background at B-Factories

Abstract

We give an estimate of the $C$-even $B^0\overline{B^0}$ background coming from the radiative decay ${\rm Y}(4S)\to B^0{\bar{B}}^0\gamma$ at $B$-factories. Our result $B({\rm Y}(4S)\to B^0{\bar{B}}^0\gamma )\simeq 3\times 10^{-9}$ shows that such background could be safely neglected in the analyses of $CP$ violating effects.

Comments: RevTex, 8 pages, 1 figure (included)