2,104 research outputs found
Constraining the Kpi vector form factor by tau---> K pi nu_tau and K_l3 decay data
A subtracted dispersive representation of the vector form factor,
, is used to fit the Belle spectrum of \tauKpi decays
incorporating constraints from results on decays. Through the use of
three subtractions, the slope and curvature of are obtained
directly from the data yielding
and . The phase-space integrals
relevant for analyses are calculated. Additionally, from the pole
position on the second Riemann sheet the mass and width of the
are found to be MeV and
MeV. Finally, we study the -wave
isospin-1/2 phase-shift and its threshold parameters.Comment: Talk presented at 15th International QCD Conference, Montpellier,
France. Submitted to Nuc. Phys. (Proc. Suppl.), 4 pages, 1 figur
Dispersive representation of the K pi vector form factor and fits to tau -> K pi nu(tau) and Ke3 data
Recently, we introduced several dispersive representations for the vector
form factor and fitted them to the Belle spectrum of . Here, we briefly present the model and discuss the results for the
slope and curvature of arising from the best fit. Furthermore, we
compare the pole position of the charged computed from our model
with other results in the literature. Finally, we discuss the prospects of a
simultaneous fit to and spectra.Comment: Talk given at "International Workshop on Effective Field Theories:
from the pion to the upsilon", February 2009, Valencia, Spain. 7 pages, 2
figures. PoS style. Minor correction in figure
Improving the Kpi vector form factor through Kl3 constraints
The vector form factor, , used to reproduce the Belle
spectrum of \tauKpi decays is described by means of a three-times subtracted
dispersion relation also incorporating constraints from decays. The
slope and curvature of are fitted to the data yielding
and . The pole parameters of the are found to be
MeV and
MeV. The phase-space integrals relevant for analyses and the -wave
isospin-1/2 phase-shift threshold parameters are also calculated.Comment: 3 pages, uses aipproc style. Talk presented by R. Escribano at the IX
International Conference on Quark Confinement and Hadron Spectrum (QCHS09),
Madrid, Spain, 30.8-3.9.201
condensate for light quarks beyond the chiral limit
We determine the condensate for quark masses from zero up to
that of the strange quark within a phenomenologically successful modelling of
continuum QCD by solving the quark Schwinger-Dyson equation. The existence of
multiple solutions to this equation is the key to an accurate and reliable
extraction of this condensate using the operator product expansion. We explain
why alternative definitions fail to give the physical condensate.Comment: 13 pages, 8 figure
Combined analysis of the decays and
In a combined study of the decay spectra of and
decays within a dispersive representation of the
required form factors, we illustrate how the resonance parameters,
defined through the pole position in the complex plane, can be extracted with
improved precision as compared to previous studies. While we obtain a
substantial improvement in the mass, the uncertainty in the width is only
slightly reduced, with the findings MeV and
MeV. Further constraints on the width
could result from updated analyses of the and/or spectra using
the full Belle-I data sample. Prospects for Belle-II are also discussed. As the
vector form factor enters the description of the decay , we are in a position to investigate isospin violations in its
parameters like the form factor slopes. In this respect also making available
the spectrum of the transition would be extremely
useful, as it would allow to study those isospin violations with much higher
precision.Comment: 20 pages, 1figur
Étude des techniques de recouvrement de fichiers dans un système d’ordinateurs fonctionnant en télé-traitement
NonQCD contributions to heavy quark masses and sensitivity to Higgs mass
We find that if the Higgs mass is close to its present experimental lower
limit (100 GeV),Yukawa interactions in the quark-Higgs sector can make
substantial contributions to the heavy quark MS masses.Comment: 16 pages, 1 figure. Fixed a few typos (eqs (7),(34)
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