12 research outputs found
The Bosonization of the Electroweak Penguin Operators
We give the complete bosonization of the electroweak Penguin
operators and compare the result with that of the gluon Penguin
operators . We find that, in addition to the usual (constant and
current-current) parts, there are three new terms not discussed previously in
the literature. Two of these are present in the factorization approximation and
should be included in the standard definition of the -factors. The
impact of these corrections on the direct -violating parameter is briefly discussed.Comment: 9 pages, uuencoded Latex + eps file
Four Zero Texture Fermion Mass Matrices in SO(10) GUT
We attempt the integration of the phenomenologically successful four zero
texture of fermion mass matrices with the renormalizable SO(10) GUT. The
resulting scenario is found to be highly predictive. Firstly, we examine the
phenomenological implications of a class of the lepton mass matrices with
parallel texture structures and obtain interesting constraints on the
parameters of the charged lepton and the neutrino mass matrices. We combine
these phenomenological constraints with the constraints obtained from SO(10)
GUT to reduce the number of the free parameters and to further constrain the
allowed ranges of the free parameters. The solar/atmospheric mixing angles
obtained in this analysis are in fairly good agreement with the data.Comment: 14 pages, 3 figures, 1 tabl
The Physics of Mixing: and in the Chiral Quark Model
We compute the parameter and the mass difference of the system by means of the chiral quark model. The
chiral coefficients of the relevant and chiral
lagrangians are computed via quark-loop integration. We include the relevant
effects of one-loop corrections in chiral perturbation theory. The final result
is very sensitive to non-factorizable corrections of coming
from gluon condensation. The size of the gluon condensate is determined by
fitting the experimental value of the amplitude . By
varying all the relevant parameters we obtain
We evaluate within the model the long-distance contributions to
induced by the double insertion of the chiral lagrangian and
study the interplay between short- and long-distance amplitudes. By varying all
parameters we obtain Finally, we investigate the phenomenological constraints on
the Kobayashi-Maskawa parameter Im entering the determination of
.Comment: 31 pages, Latex file including 7 eps figures. Revised version to
appear in Nucl. Phys.
The Weak Chiral Lagrangian as the Effective Theory of the Chiral Quark Model
We use the chiral quark model to estimate the coefficients of the weak chiral
lagrangian as obtained from the bosonization of the ten relevant operators of
the effective quark lagrangian. All contributions of order
as well as and are included. The chiral
coefficients are given in terms of , the quark and gluon condensates
and the scale-dependent NLO Wilson coefficients of the corresponding operators.
In addition, they depend on the constituent quark mass , a parameter
characteristic of the model. The -scheme dependence of the chiral
coefficients, computed via dimensional regularization, and the Fierz
transformation properties of the operator basis are discussed in detail. We
apply our result to the evaluation of the hadronic matrix elements for the
decay , consistently including the renormalization
induced by the meson loops. The effect of this renormalization is sizable and
introduces a long-distance scale dependence that matches in the physical
amplitudes the short-distance scale dependence of the Wilson coefficients.Comment: Revised version to appear in Nucl. Phys. B 48 pages, uuencoded LATEX
file including 4 eps figure
The Selection Rule
We compute the isospin and 2 amplitudes for the decay of a kaon into
two pions by estimating the relevant hadronic matrix elements in the chiral
quark model. The results are parametrized in terms of the quark and gluon
condensates and of the constituent quark mass . The latter is a parameter
characteristic of the model, that we restrict by matching the results in the
two -schemes (HV and NDR) of dimensional regularization. We find
that, for values of these parameters within the current determinations, the
selection rule is well reproduced by means of the cumulative
effects of short-distance NLO Wilson coefficients, penguin diagrams,
non-factorizable soft-gluon corrections and meson-loop renormalization.Comment: Revised version to be published in Nuclear Physics
#epsilon#/#epsilon# O(p"4) in the chiral expansion
Consiglio Nazionale delle Ricerche - Biblioteca Centrale -. P.le Aldo Moro, 7, Rome / CNR - Consiglio Nazionale delle RichercheSIGLEITItal
The physics of K"0-K"0 mixing:B_K and DELTAM_ls in the chiral quark model
Consiglio Nazionale delle Ricerche (CNR). Biblioteca Centrale / CNR - Consiglio Nazionale delle RichercheSIGLEITItal
The DELTA I = 1/2 selection rule
Consiglio Nazionale delle Ricerche (CNR). Biblioteca Centrale / CNR - Consiglio Nazionale delle RichercheSIGLEITItal
The DELTA S = 1 weak Chiral Lagrangian as the effective theory of the Chiral quark model
Consiglio Nazionale delle Ricerche (CNR). Biblioteca Centrale / CNR - Consiglio Nazionale delle RichercheSIGLEITItal