Measurement of the CKM angle γ using B± → DK± with D → K S 0 π+π−, K S 0 K+K− decays

Journal article

A binned Dalitz plot analysis of B ± → DK ± decays, with D→K0Sπ+π− and D→K0SK+K−, is performed to measure the CP-violating observables x ± and y ±, which are sensitive to the Cabibbo-Kobayashi-Maskawa angle γ. The analysis exploits a sample of proton-proton collision data corresponding to 3.0 fb−1 collected by the LHCb experiment. Measurements from CLEO-c of the variation of the strong-interaction phase of the D decay over the Dalitz plot are used as inputs. The values of the parameters are found to be x + = (−7.7 ± 2.4 ± 1.0 ± 0.4) × 10− 2, x − = (2.5 ± 2.5 ± 1.0 ± 0.5) × 10− 2, y + = (−2.2 ± 2.5 ± 0.4 ± 1.0) × 10− 2 and y − = (7.5 ± 2.9 ± 0.5 ± 1.4) × 10− 2. The first, second, and third uncertainties are the statistical, the experimental systematic, and that associated with the precision of the strong-phase parameters. These are the most precise measurements of these observables and correspond to γ = (62 − 14 + 15) ° , with a second solution at γ → γ + 180°, and r B  = 0.080 − 0.021 + 0.019, where r B is the ratio between the suppressed and favoured B decay amplitudes.

Authors: LHCb collaboration; Aaij, R; Adeva, B; Adinolfi, M; Aidala, CA

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Springer
• Journal: Journal of High Energy Physics
• Volume: 2018
• Issue: 176
• Publication date: 2018-08-28
• Acceptance date: 2018-08-14
• DOI: 10.1007/JHEP08(2018)176
• EISSN: 1029-8479
• ISSN: 1126-6708
• Keywords: flavor physics; CP violation; Hadron-Hadron scattering (experiments); CKM angle gamma; B physics