Additional isospin-breaking effects in ∈′/∈

S. Gardner, G. Valencia

Research output: Contribution to journalArticlepeer-review

44 Scopus citations


In the analysis of ∈′/∈ it has been traditional to consider the isospin-breaking effects arising from electroweak-penguin contributions and from π0-η,η′ mixing, yet additional isospin-violating effects exist. In particular, we study the isospin violation which arises from the u-d quark mass difference in the hadronization of the gluonic penguin operator, engendering contributions of an effective ΔI = 3/2 character. Using chiral perturbation theory and the factorization approximation for the hadronic matrix elements, we find within a specific model for the low-energy constants that we can readily accommodate an increase in ∈′/∈ by a factor of two.

Original languageEnglish
Pages (from-to)355-362
Number of pages8
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Issue number2-4
StatePublished - 1999

Bibliographical note

Funding Information:
The work of S.G. and G.V. is supported in part by the DOE under contract numbers DE-FG02-96ER40989 and DE-FG02-92ER40730, respectively. We thank J.F. Donoghue, C.-J. David Lin, and M.B. Wise for useful conversations, and we thank J. Bijnens for pointing out Ref. [19] . We are grateful to the Institute for Nuclear Theory at the University of Washington, the SLAC Theory Group, the Summer Visitor's Program of the Fermilab Theory Group, and M.B. Wise for hospitality during the completion of this work.

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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