Book Description

In this paper we review the most recent results concerning B Baryons at CDF and D0, including the observation and the study of the properties of the?{sub b}−,?{sub b}− and?{sub b}{sup ±(*)}, the observation of new?{sub b}° decay modes, and a new measurement of the lifetime of the b hadrons in decays with a J/?. The?{sub b}− baryon is observed through the decay chain?{sub b}− → J/??−, where J/? →??−,?− →?K−, and? → pK−, using 4.2 fb−1 of data. The?{sub b}− mass is measured to be 6054.4 ± 6.8(stat.) ± 0.9(syst.) MeV/c2, and the lifetime 1.13{sub -0.40}{sup +0.53}(stat.) ± 0.02(syst.) ps. For the?{sub b}− the mass is measured 5790.9 ± 2.6(stat.) ± 0.8(syst.) MeV/c2 and the lifetime 1.56{sub -0.25}{sup +0.27}(stat.) ± 0.02(syst.) ps. A new accurate measurement of the properties of the resonances?{sub b}+,?{sub b}−,?*{sub b}+, and?*{sub b}− has been performed in 6 fb−1 of data, and the masses have been determined, m(?{sub b}+) = 5811.2{sub -0.8}{sup +0.9}(stat.) ± 1.7(syst.), m(?{sub b}−) = 5815.5{sub -0.5}{sup +0.6}(stat.) ± 1.7(syst.), m(?*{sub b}+) = 5832.0 ± 0.7(stat.) ± 1.8(syst.), and m(?*{sub b}−) = 5835.0 ± 0.6(stat.) ± 1.8(syst.). The?{sub b}° →?{sub c}(2595)+?− →?{sub c}+?−?+?−,?{sub b}° →?{sub c}(2625)+?− →?{sub c}+?−?+?−,?{sub b}° →?{sub c}(2455){sup ++}?−?− →?{sub c}+?−?+?−, and?{sub b}° →?{sub c}(2455)°?+?− →?{sub c}+?−?+?−. CDF has performed new measurements of the b hadron lifetimes in decays with a J/?. The measured lifetimes are the currently most precise determination of the B+, B° and?{sub b}° lifetimes. The measured values are c?(B+) = 491.4 ± 2.6(stat.) ± 2.6(syst.)?m, c?(B) = 451.7 ± 3.0(stat.) ± 2.5(syst.)?m, and c?(?{sub b}°) = 460.8 ± 13.4(stat.) {+-} 4.1(syst.)?m.