2,812 research outputs found
Critical Points in the Linear Sigma Model with Quarks
We employ a simple effective model to study the chiral dynamics of two
flavors of quarks at finite temperature and density. In particular, we
determine the phase diagram in the plane of temperature and baryon chemical
potential as a function of the pion mass. An interesting phase structure occurs
which results in zero, one or two critical points depending on the value of the
vacuum pion mass.Comment: 16 pages plus 5 figure
Finite Temperature Solitons in Non-Local Field Theories from p-Adic Strings
Non-local field theories which arise from p-adic string theories have vacuum
soliton solutions. We find the soliton solutions at finite temperature. These
solutions become important for the partition function when the temperature
exceeds m_s/g_o^2 where m_s is the string mass scale and g_o is the open string
coupling.Comment: 22 pages, 6 figure
Potentials for soft wall AdS/QCD
Soft-wall models in AdS/QCD generally have dilaton and scalar fields that
vary with the fifth-dimension coordinate. These fields can be parameterized to
yield hadron mass spectra with linear radial trajectories and to incorporate
spontaneous breaking of chiral symmetry. We show how to construct scalar
potentials which lead to such solutions.Comment: 21 pages. Version 3 matches that accepted for publication. Typos have
been corrected and references added. Substantial discussion has been added in
order to clarify our approach and the issue of the dilaton mass in Sec. 4.
Central results and conclusions remain unchanged
Modification of Z Boson Properties in Quark-Gluon Plasma
We calculate the change in the effective mass and width of a Z boson in the
environment of a quark-gluon plasma under the conditions expected in Pb-Pb
collisions at the LHC. The change in width is predicted to be only about 1 MeV
at a temperature of 1 GeV, compared to the natural width of 24907 MeV. The
mass shift is even smaller. Hence no observable effects are to be expected.Comment: 7 pages latex file with 6 embedded PS figure
Low Mass Dimuons Produced in Relativistic Nuclear Collisions
The NA60 experiment has measured low-mass muon pair production in In-In
collisions at 158 A GeV with unprecedented precision. We show that this data is
reproduced very well by a dynamical model with parameters scaled from fits to
measurements of hadronic transverse mass spectra and Hanbury-Brown and Twiss
correlations in Pb-Pb and Pb-Au collisions at the same energy. The data is
consistent with in-medium properties of and -mesons at finite
temperature and density as deduced from empirical forward-scattering
amplitudes. Inclusion of the vacuum decay of the -meson after freeze-out
is necessary for an understanding of the mass and transverse momentum spectrum
of dimuons with M \apprle 0.9 {\rm GeV}/c^2.Comment: 4 pages, 3 figures, updated hadronic analysi
Antimatter from Microscopic Black Holes
The spectrum of positrons and antiprotons produced by the outflow of high
temperature matter surrounding microscopic black holes is calculated for
energies between five GeV and the Planck energy. The results may be applicable
for the last few hours and minutes of a microscopic black hole's lifetime.Comment: 7 pages, 3 figure
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