2001/01/31 by Chuan-Hung Chen, C. Geng, C. Q. Geng · 3 citations
Physics and Astronomy · #Baryon #Black Holes and Theoretical Physics #Branching fraction #Electron #Lambda #Lepton #Muon #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Physics #Physics beyond the Standard Model #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #Quark #Standard Model (mathematical formulation) #hep-ph
paper · pdf · doi:10.1103/physrevd.63.114024
published as Phys.Rev. D63 (2001) 114024 · 12 pages, 12 figures, some typos corrected, Phys.Rev.D version
arxiv created 2001/03/13 · openalex publication_date 2001/05/09 · arxiv updated 2009/11/30 · openalex created_date 2017/05/26 · openalex updated_date 2026/08/05
We investigate the rare baryonic exclusive decays of \ensuremathΛb\ensuremath→\ensuremathΛl+l^\ensuremath-(l=e,\ensuremathμ,\ensuremathτ) with polarized \ensuremathΛ. Under the approximation of the heavy quark effective theory, in the standard model we derive the differential decay rates and various polarization asymmetries by including lepton mass effects. We find that with the long-distance effects the decay branching ratios are 5.3\ifmmode×\else\texttimes\fi10^\ensuremath-5 for \ensuremathΛb\ensuremath→\ensuremathΛl+l^\ensuremath- (l=e,\ensuremathμ) and 1.1\ifmmode×\else\texttimes\fi10^\ensuremath-5 for \ensuremathΛb\ensuremath→\ensuremathΛ\ensuremathτ+\ensuremathτ^\ensuremath-. The effects of new physics in the decay rates are also discussed. The integrated longitudinal \ensuremathΛ polarizations are \ensuremath-0.31 and \ensuremath-0.12, while that of the normal ones 0.02 and 0.01, for di-muon and tau modes, respectively. The CP-odd transverse polarization of \ensuremathΛ is zero in the standard model but it is expected to be sizable in some theories with new physics.