In a sample of 3.02 million hadronic Z(0) decays collected by the DELPHI detector, 270 J/psi --> e(+)e(-) candidates have been selected. A search for fully reconstructed B-c(+/-) mesons has yielded one B-c(+/-) --> J/psi pi(+/-) candidate, no B-c(+/-) --> J/psi e(+/-) nu(e) candidates, and one B-c(+/-) --> J/psi pi(+)pi(-)pi(+) candidate, consistent with expected background in each channel. The following 90% confidence level upper limits ate determined: Br(Z(0) --> B-c(+/-) X) x Br(B-c(+/-) --> J/psi pi(+)) < (1.05 to 0.84) x 10(-4) and Br(Z(d) --> B-c(+/-) X) x Br(B-c(+/-) --> J/psi e(+/-) nu(e)) < (5.8 to 5.0) x 10(-5), where the ranges quoted correspond to the range of predicted B-c(+/-) lifetimes from 0.4 to 1.4 ps, and Br(Z(0) --> B-c(+/-) X) x Br(B-c(+/-) --> J/psi pi(+)pi(-)pi(+/-)) < 1.75 x 10(-4), constant over the range of predicted B-c(+/-) lifetimes. (C) 1997 Elsevier Science B.V.
Search for the B-c meson
DE LOTTO, Barbara;SCURI, Fabrizio;
1997-01-01
Abstract
In a sample of 3.02 million hadronic Z(0) decays collected by the DELPHI detector, 270 J/psi --> e(+)e(-) candidates have been selected. A search for fully reconstructed B-c(+/-) mesons has yielded one B-c(+/-) --> J/psi pi(+/-) candidate, no B-c(+/-) --> J/psi e(+/-) nu(e) candidates, and one B-c(+/-) --> J/psi pi(+)pi(-)pi(+) candidate, consistent with expected background in each channel. The following 90% confidence level upper limits ate determined: Br(Z(0) --> B-c(+/-) X) x Br(B-c(+/-) --> J/psi pi(+)) < (1.05 to 0.84) x 10(-4) and Br(Z(d) --> B-c(+/-) X) x Br(B-c(+/-) --> J/psi e(+/-) nu(e)) < (5.8 to 5.0) x 10(-5), where the ranges quoted correspond to the range of predicted B-c(+/-) lifetimes from 0.4 to 1.4 ps, and Br(Z(0) --> B-c(+/-) X) x Br(B-c(+/-) --> J/psi pi(+)pi(-)pi(+/-)) < 1.75 x 10(-4), constant over the range of predicted B-c(+/-) lifetimes. (C) 1997 Elsevier Science B.V.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
