First observation of Λc+ΛK+π0 and evidence of Λc+ΛK+π+π-

Collaboration
Nov 21, 2023
11 pages
Published in:
  • Phys.Rev.D 109 (2024) 3, 032003
  • Published: Feb 1, 2024
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Abstract: (APS)
We present the first observation of the singly Cabibbo-suppressed decay Λc+ΛK+π0 with a significance of 5.7σ and the first evidence of Λc+ΛK+π+π- decay with a significance of 3.1σ, based on e+e- annihilation data recorded by the BESIII detector at the BEPCII collider. The data correspond to an integrated luminosity of 6.4fb-1, in the center-of-mass energy range from 4.600 to 4.950 GeV. We determine the branching fractions of Λc+ΛK+π0 and Λc+ΛK+π+π- relative to their Cabibbo-favored counterparts to be B(Λc+ΛK+π0)B(Λc+Λπ+π0)=(2.09±0.39stat±0.07syst)×10-2 and B(Λc+ΛK+π+π-)B(Λc+Λπ+π+π-)=(1.13±0.41stat±0.06syst)×10-2, respectively. Moreover, by combining our measured result with the world average of B(Λc+Λπ+π0), we obtain the branching fraction B(Λc+ΛK+π0)=(1.49±0.27stat±0.05syst±0.08ref)×10-3. This result significantly departs from theoretical predictions based on quark SU(3) flavor symmetry, which is underpinned by the presumption of meson pair S-wave amplitude dominance.
  • electron positron: annihilation
  • electron positron: colliding beams
  • Lambda/c+: hadronic decay
  • Lambda/c+: rare decay
  • Lambda
  • K
  • pi
  • symmetry: flavor
  • Lambda/c+: branching ratio: measured
  • branching ratio: ratio: measured