Effects of quenching and partial quenching on QCD penguin matrix elements
نویسندگان
چکیده
منابع مشابه
Effects of Quenching and Partial Quenching on Penguin Matrix Elements
In the calculation of non-leptonic weak decay rates, a “mismatch” arises when the QCD evolution of the relevant weak hamiltonian down to hadronic scales is performed in unquenched QCD, but the hadronic matrix elements are then computed in (partially) quenched lattice QCD. This mismatch arises because the transformation properties of penguin operators under chiral symmetry change in the transiti...
متن کاملEffects of Quenching and Partial Quenching on QCD Penguin Matrix Elements
with q = u, d, s, (q1q2)L,R = q1γμPL,Rq2, and PL,R = (1 ∓ γ5)/2 leftand right-handed projectors. Color indices can be contracted in two ways, corresponding to the QCD penguins Q5,6. The operators in eq. (1) are obtained by the unquenched QCD evolution of the weak operator from the weak scale ∼ MW down to the hadronic scale ∼ mc. At hadronic scales, matrix elements of these four-quark operators ...
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Recently, we pointed out that chiral transformation properties of strong penguin operators change in the transition from unquenched to (partially) quenched QCD. As a consequence, new penguin-like operators appear in the (partially) quenched theory, along with new lowenergy constants, which should be interpreted as a quenching artifact. Here, we extend the analysis to the contribution of the new...
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In a recent paper [1] Bernard, Golterman, Shamir, and Sharpe challenge the proof developed in [2–4] showing that nonperturbative effects are incorrectly treated in the rooting formalism popular for reducing the number of fermion species in the staggered formalism for dynamical quarks. Here I discuss how this challenge is based on a misunderstanding of the chiral behavior of staggered quarks. Th...
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Consider the parabolic problem u t div (a(u;ru)ru) = u p (1) for t > 0, x 2 R n under initial and boundary conditions u = 1, say. Since p is assumed positive, the right hand side becomes singular as u ! 0. When u reaches zero in nite or in nite time, one says that the solution quenches in nite or in nite time. This article gives a survey of results on this kind of problem and emphasizes those t...
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ژورنال
عنوان ژورنال: Nuclear Physics B - Proceedings Supplements
سال: 2002
ISSN: 0920-5632
DOI: 10.1016/s0920-5632(01)01706-6