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Titolo:
Dimension-eight operators in the weak OPE
Autore:
Cirigliano, V; Donoghue, JF; Golowich, E;
Indirizzi:
Univ Massachusetts, Dept Phys & Astron, Amherst, MA 01003 USA Univ Massachusetts Amherst MA USA 01003 s & Astron, Amherst, MA 01003 USA
Titolo Testata:
JOURNAL OF HIGH ENERGY PHYSICS
fascicolo: 10, volume: 2000, anno: 2000,
pagine: NIL_978 - NIL_1001
SICI:
1029-8479(200010)2000:10<NIL_978:DOITWO>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
HADRONIC MATRIX-ELEMENTS; QCD SUM-RULES; RENORMALIZATION-GROUP; DELTA-I=1/2 RULE; 4-FERMION OPERATORS; LEADING LOGARITHMS; NONLEPTONIC DECAYS; K->PI-PI DECAYS; 1/N-C EXPANSION; LIMIT;
Keywords:
standard model; weak decays; kaon physics;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
42
Recensione:
Indirizzi per estratti:
Indirizzo: Cirigliano, V Univ Massachusetts, Dept Phys & Astron, Amherst, MA 01003 USA Univ Massachusetts Amherst MA USA 01003 herst, MA 01003 USA
Citazione:
V. Cirigliano et al., "Dimension-eight operators in the weak OPE", J HIGH EN P, 2000(10), 2000, pp. NIL_978-NIL_1001

Abstract

We argue that there is a potential aw in the standard treatment of weak decay amplitudes, including that of epsilon'/epsilon. We show that (contrary to conventional wisdom) dimension-eight operators do contribute to weak amplitudes, at order G(F)alpha (s) and without 1/M-W(2) suppression. We demonstrate the existence of these operators through the use of a simple weak hamiltonian. Their contribution appears in different places depending on whichscheme is adopted in performing the OPE. If one performs a complete separation of short and long distance physics within a cutoff scheme, dimension-eight operators occur in the weak hamiltonian at order G(F)alpha (s)/mu (2),mu being the separating scale. However, in an (MS) over bar renormalization scheme for the OPE the dimension-eight operators do not appear explicitlyin the hamiltonian at order G(F)alpha (s). In this case, matrix elements must include physics above the scale mu, and it is here that dimension eighteffects enter. The use of a cutoff scheme (especially quark model methods)for the calculation of the matrix elements of dimension-six operators is inconsistent with (MS) over bar unless there is careful matching including dimension-eight operators. The contribution of dimension-eight operators canbe minimized by working at large enough values of the scale mu. We find from sum rule methods that the contribution of dimension-eight operators to the dimension-six operator Q(7)((6)) is at the 100% level for mu = 1.5 GeV. This suggests that presently available values of mu are too low to justify the neglect of these effects. Finally, we display the dimension-eight operators which appear within the Standard Model at one loop.

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Documento generato il 28/09/20 alle ore 18:38:15