Determination of the sign of the decay width difference in the bs0 system

The LHCb Collaboration

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Abstract

The interference between the K +K - S-wave and P-wave amplitudes in Bs0→J/ψK +K - decays with the K +K - pairs in the region around the (1020) resonance is used to determine the variation of the difference of the strong phase between these amplitudes as a function of K +K - invariant mass. Combined with the results from our CP asymmetry measurement in Bs0→J/ψ decays, we conclude that the Bs0 mass eigenstate that is almost CP=+1 is lighter and decays faster than the mass eigenstate that is almost CP=-1. This determines the sign of the decay width difference ΔΓ sΓ LH to be positive. Our result also resolves the ambiguity in the past measurements of the CP violating phase s to be close to zero rather than π. These conclusions are in agreement with the standard model expectations.

Original languageEnglish
Article number241801
Number of pages7
JournalPhysical Review Letters
Volume108
Issue number24
DOIs
Publication statusPublished - 11 Jun 2012
Externally publishedYes

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