Search For The Lambda Sub B Baryon At Cdf PDF Download

The CDF experiment has recorded 110 pb[sup[minus]1] of p[ovr p] collisions at[radical]s= 1.8 TeV during the 1992-1995 data taking period. Using this dataset, searches for inclusive and semileptonic[Lambda][sub b] decays were performed. The[Lambda][sub b] mass was measured to be M[sub[Lambda][sub b]][equals] 5623[plus-minus] 5(stat.)[plus-minus] 4(syst.) MeV/c[sup 2], using a sample of exclusively reconstructed[Lambda][sub b] candidate events in the[Lambda][sub b][r-arrow][Lambda]J/[psi] channel. The[Lambda][sub b] lifetime was measured to be[tau][sub[Lambda][sub b]][equals] 1. 32[plus-minus] 0.08(stat.)[plus-minus] 0.05(syst.) ps, using a sample of 197[plus-minus] 25 partially reconstructed semileptonic[Lambda][sub b][r-arrow] l[sup[minus]][Lambda][sub c][sup[plus]]X decays, with[Lambda][sub c][sup[plus]] reconstructed from its decay to the pK[sup[minus]][pi][sup[plus]] final state. Using the same decay channels, the product branching ratios were measured to be f(b[r-arrow][Lambda][sub b])B([Lambda][sub b][r-arrow][Lambda]J/[psi])= 4.2[plus-minus]1.8(stat.)[plus-minus]0.7(syst.)[times]10[sup[minus]5] and f(b[r-arrow][Lambda][sub b])B([Lambda][sub b][r-arrow] l[sup[minus]][Lambda][sub c][sup[plus]][ovr[nu]])B([Lambda][sub c][sup[plus]][r-arrow] pK[sup[minus]][pi][sup[plus]])[equals] 9.3[plus-minus]2.5(stat.)[plus-minus][sup[plus]4.6][sub[minus]4.0](syst.)[times]10[sup[minus]4], where f(b[r-arrow][Lambda][sub b]) is the fraction of b quarks forming b baryons, and l is either an electron or a muon. 15 refs., 4 figs., 1 tab.