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Title: Evidence for CP Violation in B{sup 0}{yields}D{sup +}D{sup -} Decays

Journal Article · · Physical Review Letters
; ; ; ; ; ;  [1]; ; ; ; ; ; ; ; ; ; ; ; ;  [2]
  1. J. Stefan Institute, Ljubljana (Slovenia)
  2. High Energy Accelerator Research Organization (KEK), Tsukuba (Japan)

We report measurements of the branching fraction and CP violation parameters in B{sup 0}{yields}D{sup +}D{sup -} decays. The results are based on a data sample that contains 535x10{sup 6} BB pairs collected at the {upsilon}(4S) resonance, with the Belle detector at the KEKB asymmetric-energy e{sup +}e{sup -} collider. We obtain [1.97{+-}0.20(stat){+-}0.20(syst)]x10{sup -4} for the branching fraction of B{sup 0}{yields}D{sup +}D{sup -}. The measured values of the CP violation parameters are S=-1.13{+-}0.37{+-}0.09, A=0.91{+-}0.23{+-}0.06, where the first error is statistical and the second is systematic. We find evidence of CP violation in B{sup 0}{yields}D{sup +}D{sup -} at the 4.1{sigma} confidence level. While the value of S is consistent with expectations from other measurements, the value of the parameter A favors large direct CP violation at the 3.2{sigma} confidence level, in contradiction to standard model expectations.

OSTI ID:
20951442
Journal Information:
Physical Review Letters, Vol. 98, Issue 22; Other Information: DOI: 10.1103/PhysRevLett.98.221802; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0031-9007
Country of Publication:
United States
Language:
English