738 research outputs found
Dark polariton-solitons in semiconductor microcavities
We report the existence, symmetry breaking and other instabilities of dark
polariton-solitons in semiconductor microcavities operating in the strong
coupling regime. These half-light half-matter solitons are potential candidates
for applications in all-optical signal processing. Their excitation time and
required pump powers are a few orders of magnitude less than those of their
weakly coupled light-only counterparts.Comment: submitted to PR
Hadron Resonance Gas Model with Induced Surface Tension
Here we present a physically transparent generalization of the multicomponent
Van der Waals equation of state in the grand canonical ensemble. For the
one-component case the third and fourth virial coefficients are calculated
analytically. It is shown that an adjustment of a single model parameter allows
us to reproduce the third and fourth virial coefficients of the gas of hard
spheres with small deviations from their exact values. A thorough comparison of
the compressibility factor and speed of sound of the developed model with the
one and two component Carnahan-Starling equation of state is made. It is shown
that the model with the induced surface tension is able to reproduce the
results of the Carnahan-Starling equation of state up to the packing fractions
0.2-0.22 at which the usual Van der Waals equation of state is inapplicable. At
higher packing fractions the developed equation of state is softer than the gas
of hard spheres and, hence, it breaks causality in the domain where the
hadronic description is expected to be inapplicable. Using this equation of
state we develop an entirely new hadron resonance gas model and apply it to a
description of the hadron yield ratios measured at AGS, SPS, RHIC and ALICE
energies of nuclear collisions. The achieved quality of the fit per degree of
freedom is about 1.08. We confirm that the strangeness enhancement factor has a
peak at low AGS energies, while at and above the highest SPS energy of
collisions the chemical equilibrium of strangeness is observed. We argue that
the chemical equilibrium of strangeness, i.e. , observed
above the center of mass collision energy 4.3 GeV may be related to the
hadronization of quark gluon bags which have the Hagedorn mass spectrum, and,
hence, it may be a new signal for the onset of deconfinement
Procedure for Event Characterization in Pb-Pb Collisions at 40A GeV in the NA49 Experiment at the CERN SPS
The time evolution of the strongly interacting matter created in a heavy-ion collision depends on the initial geometry and the collision centrality. This makes important the experimental determination of the collision geometry. In this paper a procedure for event classification and estimation of the geometrical parameters in inelastic Pb-Pb collisions at the beam energy of 4
Hard-core Radius of Nucleons within the Induced Surface Tension Approach
In this work we discuss a novel approach to model the hadronic and nuclear
matter equations of state using the induced surface tension concept. Since the
obtained equations of state, classical and quantum, are among the most
successful ones in describing the properties of low density phases of strongly
interacting matter, they set strong restrictions on the possible value of the
hard-core radius of nucleons. Therefore, we perform a detailed analysis of its
value which follows from hadronic and nuclear matter properties and find the
most trustworthy range of its values: the hard-core radius of nucleons is
0.30--0.36 fm. A comparison with the phenomenology of neutron stars implies
that the hard-core radius of nucleons has to be temperature and density
dependent.Comment: 12 pages, 4 figures, references added, typos correcte
Resonance structure in the {\gamma}{\gamma} and systems in dC interactions
Along with and {\eta} mesons, a resonance structure in the invariant
mass spectrum of two photons at M{\gamma}{\gamma} = 360 \pm 7 \pm 9 MeV is
observed in the reaction d + C \rightarrow {\gamma} + {\gamma} + X at momentum
2.75 GeV/c per nucleon. Estimates of its width and production cross section are
{\Gamma} = 64 \pm 18 MeV and = 98 \pm 24 {\mu}b,
respectively. The collected statistics amount to 2339 \pm 340 events of 1.5
\cdot 10^6 triggered interactions of a total number ~ 10^12 of dC-interactions.
The results on observation of the resonance in the invariant mass spectra of
two mesons are presented: the data obtained in the d + C \rightarrow
{\gamma} + {\gamma} reaction is confirmed by the d + C \rightarrow +
reaction: = 359.2 \pm 1.9 MeV, {\Gamma} = 48.9 \pm 4.9
MeV; the ratio of Br(R\rightarrow{\gamma}{\gamma}) /
Br(R\rightarrow) = (1.8 {\div} 3.7)\cdot10^-3.Comment: 10 pages, 11 figure
The comparison of methods for anisotropic flow measurements with the MPD Experiment at NICA
The anisotropic collective flow is one of the key observables to study the
properties of dense matter created in heavy-ion collisions. The performance of
Multi-Purpose Detector (MPD) at NICA collider for directed and elliptic flow
measurements is studied with Monte-Carlo simulations of heavy-ion collisions at
energies = 4 - 11 GeV.Comment: 10 pages, 8 figures, to be published in the Proceedings of the
Conference "RFBR Grants for NICA" (Dubna, 20-23 October 2020), Journal
Physics of Elementary Particles and Atomic Nucle
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