On ε{lunate}K beyond lowest order in the operator product expansion

Andrzej J. Buras, Diego Guadagnoli, Gino Isidori

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Abstract

We analyse the structure of long distance (LD) contributions to the CP-violating parameter ε{lunate}K, that generally affect both the absorptive (Γ12) and the dispersive (M12) parts of the K0 - over(K, ̄)0 mixing amplitude. We point out that, in a consistent framework, in addition to LD contributions to Im Γ12, estimated recently by two of us, also LD contributions to Im M12 have to be taken into account. Estimating the latter contributions the impact of LD effects on ε{lunate}K is significantly reduced (from -6.0% to -3.6%). The overall effect of LD corrections and of the superweak phase being different from 45° is summarised by the multiplicative factor κε{lunate} = 0.94 ± 0.02.

Original languageEnglish
Pages (from-to)309-313
Number of pages5
JournalPhysics Letters B
Volume688
Issue number4-5
DOIs
StatePublished - 10 May 2010

Keywords

  • CP violation
  • Effective theories
  • K mesons
  • Standard Model

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