학술논문

A measurement of the CP asymmetry difference between Λc+ → pK − K + and pπ−π+ decays
Document Type
article
Source
Journal of High Energy Physics. 2018(3)
Subject
Charm physics
CP violation
Flavor physics
Hadron-Hadron scattering
hep-ex
Nuclear & Particles Physics
Mathematical Sciences
Physical Sciences
Mathematical Physics
Atomic
Molecular
Nuclear
Particle and Plasma Physics
Quantum Physics
Atomic
Molecular
Nuclear
Particle and Plasma Physics
Language
Abstract
The difference between the CP asymmetries in the decays Λc+ → pK−K+ and Λc+ → pπ−π+ is presented. Proton-proton collision data taken at centre-of-mass energies of 7 and 8 TeV collected by the LHCb detector in 2011 and 2012 are used, corresponding to an integrated luminosity of 3 fb−1. The Λc+ candidates are reconstructed as part of the Λb0 → Λc+μ−X decay chain. In order to maximize the cancellation of production and detection asymmetries in the difference, the final-state kinematic distributions of the two samples are aligned by applying phase-space-dependent weights to the Λc+ → pπ−π+ sample. This alters the definition of the integrated CP asymmetry to ACPwgt(pπ−π+). Both samples are corrected for reconstruction and selection efficiencies across the five-dimensional Λc+ decay phase space. The difference in CP asymmetries is found to be ΔACPwgt=ACP(pK−K+)−ACPwgt(pπ−π+)=(0.30±0.91±0.61)%, where the first uncertainty is statistical and the second is systematic.[Figure not available: see fulltext.].