Measurement of branching ratio of the B decay to chic and kaon

Abstract

We report on a measurement of the branching ratio of the decay B"^ -> Xci (1-^)^ • Here "we" represents our HEP group, because this work is completed by me under the assistance of other members of our group. It is the first time that the B —> Xci(l-P)^''' decay is reconstructed in pp collisions, although it has been previously observed in e^e~ collisions. The data sample consists of 110 pb~^ of pp collisions at a center of mass energy of 1.8 TeV collected by the Collider Detector at Fermilab (CDF). This data was collected during Run I of the Tevatron from 1992 through 1995. The Xci(l-P) meson is reconstructed via the decay Xci(l^) —)• J/ip'j, and the J/-^ meson is reconstructed via the decay J/ip -^ /w"*"/^"- Signals of 18.7 ± 5.6 B^ -^ Xci(l-P)^^ events and 487.3±24.2 B'^ -> J/ipK^ events are observed. Using these numbers along with acceptance corrections calculated from detector simulations we determine the ratio of branching ratios BR(5+ -^ Xci(l^)^^)/BR(5+ - i J/^K^). Then by using the world average Particle Data Group (PDG) value for BR(5+ -)> J/ipK'^), we calculate the branching ratio BR(5+ ^ Xci(l^)^^) to be (9.0±3.0{stat)±l.2(sys))xl0-\ which has a comparable error to the value quoted in the PDG.