1,976 research outputs found
Calibrating the Na\"ive Cornell Model with NRQCD
Along the years, the Cornell Model has been extraordinarily successful in
describing hadronic phenomenology, in particular in physical situations for
which an effective theory of the strong interactions such as NRQCD cannot be
applied. As a consequence of its achievements, a relevant question is whether
its model parameters can somehow be related to fundamental constants of QCD. We
shall give a first answer in this article by comparing the predictions of both
approaches. Building on results from a previous study on heavy meson
spectroscopy, we calibrate the Cornell model employing NRQCD predictions for
the lowest-lying bottomonium states up to NLO, in which the bottom mass is
varied within a wide range. We find that the Cornell model mass parameter can
be identified, within perturbative uncertainties, with the MSR mass at the
scale GeV. This identification holds for any value of or
the bottom mass, and for all perturbative orders investigated. Furthermore, we
show that: a) the "string tension" parameter is independent of the bottom mass,
and b) the Coulomb strength of the Cornell model can be related to the
QCD strong coupling constant at a characteristic non-relativistic
scale. We also show how to remove the renormalon of the static QCD
potential and sum-up large logs related to the renormalon subtraction by
switching to the low-scale, short-distance MSR mass, and using R-evolution. Our
R-improved expression for the static potential remains independent of the heavy
quark mass value and agrees with lattice QCD results for values of the radius
as large as fm, and with the Cornell model potential at long distances.
Finally we show that for moderate values of , the R-improved NRQCD and
Cornell static potentials are in head-on agreement.Comment: 22 pages, 13 figures, 3 table
Puzzles in quarkonium hadronic transitions with two pion emission
The anomalously large rates of some hadronic transitions from quarkonium are
studied using QCD multipole expansion (QCDME) in the framework of a constituent
quark model which has been successful in describing hadronic phenomenology. The
hybrid intermediate states needed in the QCDME method are calculated in a
natural extension of our constituent quark model based on the Quark Confining
String (QCS) scheme. Some of the anomalies are explained due to the presence of
an hybrid state with a mass near the mass of the decaying resonance whereas
other are justified by the presence of molecular components in the wave
function. Some unexpected results are pointed out.Comment: Conference proceedings of the XI Quark Confinement and the Hadron
Spectrum (CONFINEMENT XI). Saint Petersburg (Russia) from 8 to 12 September
201
Molecular components in P-wave charmed-strange mesons
Results obtained by various experiments show that the
and mesons are very narrow states located below the and
thresholds, respectively. This is markedly in contrast with the
expectations of naive quark models and heavy quark symmetry. Motivated by a
recent lattice study which addresses the mass shifts of the ground
states with quantum numbers () and
() due to their coupling with -wave
thresholds, we perform a similar analysis within a
nonrelativistic constituent quark model in which quark-antiquark and
meson-meson degrees of freedom are incorporated. The quark model has been
applied to a wide range of hadronic observables and thus the model parameters
are completely constrained. The coupling between quark-antiquark and
meson-meson Fock components is done using a model in which its only
free parameter has been elucidated performing a global fit to the
decay widths of mesons that belong to different quark sectors, from light to
heavy. We observe that the coupling of the meson sector to
the threshold is the key feature to simultaneously lower the
masses of the corresponding and states
predicted by the naive quark model and describe the meson as the
state of the doublet predicted by heavy quark
symmetry, reproducing its strong decay properties. Our calculation allows to
introduce the coupling with the -wave channel and the
computation of the probabilities associated with the different Fock components
of the physical state.Comment: 11 pages, 3 figures, 7 table
In-vitro experiment of Listeria reduction in ready-to-eat dry cured sausages
The risk of listeriosis associated with ready-to-eat foods is a major concern in United States. The recently published United States regulations require ready-to-eat meat producers to control Listeria monocytogenes, using interventions which may include antimicrobials that reduce post-processing contamination by at least 1 log cycle and that no more than 1 log increase throughout product shelf life. This regulation impact also the Spanish meat producers especially dry cured sausages, which export their products to USA. In this study, we analyzed in vitro, individually and in combinations, the commonly applied antimicrobials to reduce Listeria. Performing in-vitro experiment before applying directly on dry cured sausages offer us the benefits such as time and cost saving
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