Spectator interactions in soft-collinear effective theory

Richard J. Hill, Matthias Neubert

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125 Scopus citations


Soft-collinear effective theory is generalized to include soft massless quarks in addition to collinear fields. This extension is necessary for the treatment of interactions with the soft spectator quark in a heavy meson. The power counting of the relevant fields and the construction of the effective Lagrangian are discussed at leading order in Λ/m b . Several novel effects occur in the matching of full-theory amplitudes onto effective-theory operators containing soft light quarks, such as the appearance of an intermediate mass scale and large non-localities of operators on scales of order 1/Λ. Important examples of effective-theory operators with soft light quarks are studied and their renormalization properties explored. The formalism presented here forms the basis for a systematic analysis of factorization and power corrections for any exclusive B-meson decay into light particles.

Original languageEnglish
Pages (from-to)229-256
Number of pages28
JournalNuclear Physics B
Issue number1-3
StatePublished - May 5 2003

Bibliographical note

Funding Information:
We are grateful to Martin Beneke, Peter Lepage, Ben Pecjak, Björn Lange, Farrukh Chishtie and Stefan Bosch for many useful discussions. The research of R.J.H. was supported by the Department of Energy under Grant DE-AC03-76SF00515. The research of M.N. was supported by the National Science Foundation under Grant PHY-0098631.

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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