1,715 research outputs found
Influence of pions on the hadron-quark phase transition
In this work we present the features of the hadron-quark phase transition
diagrams in which the pions are included in the system. To construct such
diagrams we use two different models in the description of the hadronic and
quark sectors. At the quark level, we consider two distinct parametrizations of
the Polyakov-Nambu-Jona-Lasinio (PNJL) models. In the hadronic side, we use a
well known relativistic mean-field (RMF) nonlinear Walecka model. We show that
the effect of the pions on the hadron-quark phase diagrams is to move the
critical end point (CEP) of the transitions lines. Such an effect also depends
on the value of the critical temperature (T_0) in the pure gauge sector used to
parametrize the PNJL models. Here we treat the phase transitions using two
values for T_0, namely, T_0 = 270 MeV and T_0 = 190 MeV. The last value is used
to reproduce lattice QCD data for the transition temperature at zero chemical
potential.Comment: 3 pages. Proceedings of XXXV Reuni\~ao de Trabalhos sobre F\'isica
Nuclear no Brasil 201
Scaling functions of two-neutron separation energies of with finite range potentials
The behaviour of an Efimov excited state is studied within a three-body
Faddeev formalism for a general neutron-neutron-core system, where neutron-core
is bound and neutron-neutron is unbound, by considering zero-ranged as well as
finite-ranged two-body interactions. For the finite-ranged interactions we have
considered a one-term separable Yamaguchi potential. The main objective is to
study range corrections in a scaling approach, with focus in the exotic carbon
halo nucleus
Universal description of S-wave meson spectra in a renormalized light-cone QCD-inspired model
A light-cone QCD-inspired model, with the mass squared operator consisting of
a harmonic oscillator potential as confinement and a Dirac-delta interaction,
is used to study the S-wave meson spectra. The two parameters of the harmonic
potential and quark masses are fixed by masses of rho(770), rho(1450), J/psi,
psi(2S), K*(892) and B*. We apply a renormalization method to define the model,
in which the pseudo-scalar ground state mass fixes the renormalized strength of
the Dirac-delta interaction. The model presents an universal and satisfactory
description of both singlet and triplet states of S-wave mesons and the
corresponding radial excitations.Comment: RevTeX, 17 pages, 7 eps figures, to be published in Phys. Rev.
Effective range from tetramer dissociation data for cesium atoms
The shifts in the four-body recombination peaks, due to an effective range
correction to the zero-range model close to the unitary limit, are obtained and
used to extract the corresponding effective range of a given atomic system. The
approach is applied to an ultracold gas of cesium atoms close to broad Feshbach
resonances, where deviations of experimental values from universal model
predictions are associated to effective range corrections. The effective range
correction is extracted, with a weighted average given by 3.9,
where is the van der Waals length scale; which is consistent with the
van der Waals potential tail for the system. The method can be generally
applied to other cold atom experimental setups to determine the contribution of
the effective range to the tetramer dissociation position.Comment: A section for two-, three- and four-boson bound state formalism is
added, accepted for publication in Phys. Rev.
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