First Observation of An Excited Charm Baryon Decaying to Omega Charm Baryon at the BaBar Experiment

Thesis/Dissertation · Sun Jan 01 00:00:00 EST 2006

DOI:https://doi.org/10.2172/920288· OSTI ID:920288

Bula, Rahmi ^[1]

---

1. State Univ. of New York (SUNY), Albany, NY (United States)

We have carried out a search for a charmed baryon Ω$$*\atop{c}$$ decaying to Ω$$0\atop{c}$$ and a γ where Ω _c candidates are reconstructed using decay modes Ω^-π⁺(c1), Ω^-π⁺π⁰(c2), Ω^-π⁺π^-π⁺(c3) and Ξ^-K^-π⁺π⁺(c4). This search is performed by analyzing integrated luminosity of 230.7 fb^-1 data collected by the BABAR detector at the Stanford Linear Accelerator Center. In decay channel Ω$$*\atop{c}$$ → Ω$$0\atop{c}$$(Ω^-π⁺)γ (C1), we observe a signal yield of 39.2$$+9.8\atop{-9.1}$$ (stat)±6.0(syst) events with a significance of 4.2 standard deviations. In decay channels Ω$$*\atop{c}$$ → Ω$$0\atop{c}$$(Ω^-π⁺π⁰)γ (C2) and Ω$$*\atop{c}$$ →} Ω$$0\atop{c}$$(Ξ^-K^-π⁺π⁺)γ (C4), we observe signal yields of 55.2$$+16.1\atop{-15.2}$$ ± 5.6 and 20.2$$+9.3\atop{-8.5}$$ ± 3.1 with significances of 3.4 and 2.0 σ, respectively. As for the Ω$$*\atop{c}$$ → Ω$$0\atop{c}$$(Ω^-π⁺π^-π⁺)γ (C3) decay channel, we observe signal yields of -5.1$$+5.3.8\atop{-4.7}$$±1.0 without a positive significance. We assume the same production mechanism for the four decay channels of Ω$$*\atop{c}$$ studied. By combining these four channels, the fit results in a signal yield of 105.3$$+21.2\atop{-20.5}$$± 6.0 events with a significance of 5.2 σ. We report the mass difference Ω$$*\atop{c}$$ - Ω$$0\atop{c}$$(δm) of the singly charmed baryon Ω$$*\atop{c}$$ to be 70.8$$+1.0\atop{-1.0}$$±1.1 MeV. Finally, the ratios of production cross sections are calculated: σ(e⁺e^-→C1)/σ(e⁺e^-→c1) = 0.71$$+0.19\atop{-0.18}$$±0.11, σ(e⁺e^-→C2)/σ(e⁺e^-→c2) = 1.76$$+0.71\atop{-0.69}$$±0.19, σ(e⁺e^-→C3)/σ(e⁺e^-→c3) = -0.66$$+0.74\atop{-0.66}$$±0.13, σ(e⁺e^-→C4)/σ(e⁺e^-→c4) = 1.70{sup +1.0}{sub -1.0}±0.27 and σ(e⁺e^-→Ω$$*\atop{c}$$ (combined))/σ(e⁺e^-→Ω$$0\atop{c}$$) = 1.0$$+0.23\atop{-0.22}$$±0.11.

• Research Organization: SLAC National Accelerator Lab., Menlo Park, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 920288
• Report Number(s): SLAC-R-881; TRN: US0807415
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
BARYONS
CHARMED BARYONS
CROSS SECTIONS
DECAY
LUMINOSITY
MASS DIFFERENCE
PRODUCTION
STANFORD LINEAR ACCELERATOR CENTER
Experiment-HEP
HEPEX