Measurement of the CKM angle γ using B±DK ± with D →KS0 π+π, KS0 K+K decays

The LHCb Collaboration

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Abstract

A binned Dalitz plot analysis of B± → DK± decays, with D → KS 0π+π− and D → KS 0K+K−, is used to perform a measurement of the CP-violating observables x± and y±, which are sensitive to the Cabibbo-Kobayashi-Maskawa angle γ. The analysis is performed without assuming any D decay model, through the use of information on the strong-phase variation over the Dalitz plot from the CLEO collaboration. Using a sample of proton-proton collision data collected with the LHCb experiment in 2015 and 2016, and corresponding to an integrated luminosity of 2.0 fb−1, the values of the CP violation parameters are found to be x− = (9.0 ± 1.7 ± 0.7 ± 0.4) × 10−2, y− = (2.1 ± 2.2 ± 0.5 ± 1.1) × 10−2, x+ = (−7.7 ± 1.9 ± 0.7 ± 0.4) × 10−2, and y+ = (−1.0 ± 1.9 ± 0.4 ± 0.9) × 10−2. The first uncertainty is statistical, the second is systematic, and the third is due to the uncertainty (on the strong-phase measurements. These values are used to obtain γ = (87− 12 + 11)∘, rB = 0.086− 0.014 + 0.013, and δB = (101±11)°, where rB is the ratio between the suppressed and favoured B-decay amplitudes and δB is the corresponding strong-interaction phase difference. This measurement is combined with the result obtained using 2011 and 2012 data collected with the LHCb experiment, to give γ = (80− 9 + 10)∘, rB = 0.080 ± 0.011, and δB = (110 ± 10)°.
Original languageEnglish
Article number176
Number of pages36
JournalJournal of High Energy Physics
Volume2018
Issue number8
DOIs
Publication statusPublished - 2018
Externally publishedYes

Keywords

  • B Physics
  • CKM angle gamma
  • CP violation
  • Flavor physics
  • Hadron-Hadron scattering (experiments)

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