7,295 research outputs found
On three-body B decays to charm
I briefly describe the use of the three-body decay modes to investigate open issues in charmed meson spectroscopy, and of
the time dependent transitions for
a measurement of .Comment: LaTeX, 4 pages, 4 figs. Talk at 5th International Conference on
Hyperons, Charm and Beauty Hadrons (BEACH 2002), Vancouver, Canada, 25-29 Jun
200
B decays to excited charm mesons
We review several aspects of the phenomenology of P-wave mesons:
mass splittings, effective strong couplings and leptonic constants. We also
describe a QCD sum rule determination to order of the form factor
governing the semileptonic decays to the charm doublet with
.Comment: LaTex, 3 pages, 1 figure. Talk given at 3rd International Conference
on Hyperons, Charm and Beauty Hadrons, Genoa, Italy, 30 Jun - 3 Jul 199
The pion and proton mass in finite volume
We calculate the finite volume effects for the pion and nucleon mass. For the
pion mass we present the results of a full two-loop calculation in chiral
perturbation theory. The outcome shows that the resummed version of the Luscher
formula we presented in an earlier work does indeed give an excellent
approximation to the two-loop result. In view of this result we apply the same
resummed formula to the nucleon mass. In the nucleon sector the extension of
the chiral expansion to higher quark masses appears to be more problematic and
it is therefore more difficult to make reliable predictions for the size of the
finite volume effects. We present some preliminary numerical estimates.Comment: 10 pages, 3 figures, Talk given at the Workshop on Computational
Hadron Physics, Cyprus, September 14-17, 200
Finite volume effects for the pion mass at two loops
We evaluate the pion mass in finite volume to two loops within Chiral
Perturbation Theory. The results are compared with a recently proposed
extension of the asymptotic formula of Luscher. We find that contributions,
which were neglected in the latter, are numerically very small at the two-loop
level and conclude that for Mpi*L>2, L>2fm the finite volume effects in the
meson sector are analytically well under control.Comment: 26 pages, 6 figure
The quenched generating functional for hadronic weak interactions
The ultraviolet behaviour of the generating functional for hadronic weak
interactions with is investigated to one loop for a generic
number of flavours and in the quenched approximation. New quenched chiral
logarithms generated by the weak interactions can be accounted for via a
redefinition of the weak mass term in the weak effective
Lagrangian at leading order. Finally, we illustrate how chiral logarithms are
modified by the quenched approximation in matrix elements with
and 3/2.Comment: LATTICE98(matrixelement), 3 page
Anomalous vertex in the soft-wall holographic model of QCD
We discuss the vertex function of two vector and one axial-vector operators
in the soft-wall holographic model of QCD. When one of the two vector currents
represents an on-shell soft photon, such a vertex is described by two structure
functions and , which are usually calculated through triangular loop
diagrams. We evaluate these functions in the soft-wall model of holographic QCD
(HQCD) and compare the outcome to the QCD findings.Comment: 4 pages, contribution to conference "QCD 12", 16th International
Conference in Quantum ChromoDynamics, 2nd-6th july 2012 (Montpellier -
France
The Riddle of Polarization in Transitions
Measurements of polarization fractions in transitions, with a
light vector meson, show that the longitudinal amplitude dominates in , , and decays and
not in the penguin induced decays , .
We study the effect of rescattering mediated by charmed resonances, finding
that in it can be responsible of the suppression of the
longitudinal amplitude. For the decay we find that the
longitudinal fraction cannot be too large without invoking new effects.Comment: LaTex, 14 pages, 3 figure
pi pi scattering, pion form factors and chiral perturbation theory
I discuss recent progress in our understanding of the pi pi scattering
amplitude at low energy thanks to the combined use of chiral perturbation
theory and dispersion relations. I also comment on the criticism raised by
Pelaez and Yndurain on this work.Comment: 10 pages, 5 figures. Invited talk at the "Quark Confinement and the
Hadron Spectrum" VI Conference, Villasimius, Sardinia, Italy, 21-25 September
200
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