Mass and Lifetime Measurements of Bottom and Charm Baryons in p[bar over p] Collisions at √s = 1.96 TeV

• Main Authors: Gomez-Ceballos, Guillelmo (Contributor), Goncharov, Maxim (Contributor), Paus, Christoph M. E. (Contributor)
• Other Authors: Massachusetts Institute of Technology. Laboratory for Nuclear Science (Contributor)
• Format: Article
• Language: English
• Published: American Physical Society, 2014-08-25T14:30:12Z.
• Subjects: Article
• Online Access: Get fulltext

We report on mass and lifetime measurements of several ground state charmed and bottom baryons, using a data sample corresponding to 9.6  fb[superscript −1] from p[bar over p] collisions at √s = 1.96  TeV and recorded with the Collider Detector at Fermilab. Baryon candidates are reconstructed from data collected with an online event selection designed for the collection of long-lifetime heavy-flavor decay products and a second event selection designed to collect J/ψ → μ[superscript +]μ[superscript −] candidates. First evidence for the process Ω[− over b] → Ω[0 over c]π[superscript −] is presented with a significance of 3.3σ. We measure the following baryon masses: M(Ξ[0 over c]) 2470.85 ± 0.24(stat) ± 0.55(syst) MeV/c[superscript 2], M(Ξ[+ over c]) = 2468.00 ± 0.18(stat) ± 0.51(syst)  MeV/c[superscript 2], M(Λ[subscript b]) = 5620.15 ± 0.31(stat) ± 0.47(syst)  MeV/c[superscript 2], M(Ξ[− over b]) = 5793.4 ± 1.8(stat) ± 0.7(syst)  MeV/c[superscript 2], M(Ξ[0 over b]) = 5788.7 ± 4.3(stat) ± 1.4(syst)  MeV/c[superscript 2], and M(Ω[− over b]) = 6047.5 ± 3.8(stat) ± 0.6(syst)  MeV/c[superscript 2]. The isospin splitting of the Ξ[− over b][superscript ,0] states is found to be M(Ξ[− over b]) − M(Ξ[0 over b]) = 4.7 ± 4.7(stat) ± 0.7(syst)  MeV/c[superscript 2]. The isospin splitting of the Ξ[0 over c][superscript ,+] states is found to be M(Ξ[0 over c]) − M(Ξ[+ over c]) = 2.85 ± 0.30(stat) ± 0.04(syst)  MeV/c[superscript 2]. The following lifetime measurements are made: τ(Λ[subscript b]) = 1.565 ± 0.035(stat) ± 0.020(syst)  ps, τ(Ξ[−over b]) = 1.32 ± 0.14(stat) ± 0.02(syst)  ps, τ(Ω[− over b]) = 1.66[+0.53 over −0.40](stat) ± 0.02(syst)  ps.
United States. Dept. of Energy
National Science Foundation (U.S.)
Alfred P. Sloan Foundation