content_type = "text/plain"
user_agent = "Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)"
moz = "Mozilla/5.0 "
moz_version = "5"
We measure the branching fraction for the
flavor-changing neutral-current process B -> Xs l+ l- with
a sample of 89 x 10^6 Upsilon(4S) -> BBbar events
recorded with the BaBar detector at the PEP-II e+e- storage ring.
The final state is reconstructed from e+e- or mu+mu- pairs
and a hadronic system consisting of one K or K0s and up to
two pions, with at most one pi0.
We observe a signal of 40 +/- 10(stat) +/- 2(syst) events
and extract the inclusive branching fraction
B(B -> Xs l+ l-) =
(5.6 +/- 1.5(stat) +/- 0.6(exp syst) +/- 1.1(model syst)) x 10^-6
for mll > 0.2 GeV/c^2.
|
