Mass and Lifetime Measurements of Bottom and Charm Baryons in p[bar over p] Collisions at √s = 1.96 TeV
Author(s)
Gomez-Ceballos, Guillelmo; Goncharov, Maxim; Paus, Christoph M. E.
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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.
Date issued
2014-04Department
Massachusetts Institute of Technology. Laboratory for Nuclear ScienceJournal
Physical Review D
Publisher
American Physical Society
Citation
Aaltonen, T., S. Amerio, D. Amidei, A. Anastassov, A. Annovi, J. Antos, G. Apollinari, et al. “Mass and Lifetime Measurements of Bottom and Charm Baryons in p[bar over p] Collisions at √s = 1.96 TeV.” Phys. Rev. D 89, no. 7 (April 2014). © 2014 American Physical Society
Version: Final published version
ISSN
1550-7998
1550-2368