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An improved measurement of direct CP violation parameters in B^+- -> J/psi K^+- and B^+- -> J/psi pi^+- decays

Research output: Contribution to journalJournal article


Article number241801
Journal publication date12/06/2013
JournalPhysical Review Letters
Number of pages7
Original languageEnglish


We present a measurement of the direct CP-violating charge asymmetry in B± mesons decaying to J/ψK± and J/ψπ± where J/ψ decays to μ+μ-, using the full run II data set of 10.4  fb-1 of proton-antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. A difference in the yield of B- and B+ mesons in these decays is found by fitting to the difference between their reconstructed invariant mass distributions resulting in asymmetries of AJ/ψK=[0.59±0.37]%, which is the most precise measurement to date, and AJ/ψπ=[-4.2±4.5]%. Both measurements are consistent with standard model predictions.

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© 2013 American Physical Society