High precision measurements of the mass, intrinsic width, momentum spectrum and the branching fractions of Λc(2880)+ decay modes in the BABAR experiment.

摘要

This dissertation reports an acurate measurement of the mass, intrinsic width and momentum spectra of the charmed baryon Λc(2880) + along with the first measurements on the relative branching fractions of the Λc(2880)+ decaying resonantly and non-resonantly to the Λc(2286) +pi+pi- mode.; This analysis was performed using a data sample of approximately 230 fb-1 (integrated luminosity) collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at the Stanford Linear Accelerator Center. We measure the mass of the Λ c(2880)+ to be 2.8809 +/- 0.0004 (stat.) GeV/c2 and the intrinsic width to be 5.8 +/- 1.7 (stat. MeV. We also measure the relative branching fraction for each of the non-resonant and resonant decays of the Λc(2880) + → Λc(2286)+pipi final states, relative to all modes of Λc(2880) + → Λc(2286)+pipi.; The relative branching fraction for the non-resonant decay mode Λ c(2880)+ → Λc(2286) +pi+pi- relative to (Λ c(2880)+ → Λc(2286) +pi+pi-)allmodes is evaluated to be 0.385 +/- 0.087 (stat.) +0.044-0.074 (syst.), wheras the relative branching fraction for the non-resonant decay modes sumc(2455)0pi +, sumc(2520)0pi +, sumc(2455)++pi - and sumc(2520)++pi - are measured to be 0.119 +/- 0.024 (stat.) +0.026-0.014 (syst.), 0.141 +/- 0.038 (stat.) +0.020-0.013 (syst.), 0.206 +/- 0.033 (stat.) +0.026-0.013 (syst.) and 0.149 +/- 0.039 (stat.) +0.023-0.015 (syst.) respectively.; Comparison to previous experiments are also given.