35837302
Baryon-number density in hadronic gas models and baryon asymmetry in the early Universe.
We have recently shown that the inclusion of finite-size volume corrections for the hadrons in the hadronic gas phase drastically alters the conclusions regarding isothermal baryon-number fluctuations arising from a first-order quark-hadron phase transition in the early Universe. In this paper we compare in detail the predictions of various existing thermodynamically consistent hadron gas (HG) models for the baryon density in the HG phase and its dependence on the temperature in order to draw a firm conclusion regarding the results obtained in the earlier paper. \textcopyright{} 1996 The American Physical Society.
115391521
QUARK GLUON PLASMA : CURRENT STATUS OF PROPERTIES AND SIGNALS
120612824
On the Singh-Uddin-Kamal relation in the negative binomial distribution
Abstract The empirical relation between the parameters k and n of the negative binomial distribution (NBD) as proposed by Singh, Uddin and Kamal is shown to emerge from the concept of the stationary branching process. Further consequences of this relation are derived and compared with the experimental data.
119366615
Anisotropic Bianchi Type-II Cosmological Models in Self-Creation Cosmology
Totally anisotropic Bianchi type-II cosmological solutions are presented in Barber's second self-creation theory of gravitation both in vacuum and in the presence of stiff-matter. The corresponding cosmological models have no finite singularity. The stiff-matter model gives essentially an empty universe for large time. Some physical and kinematical properties of the models are discussed.
120005715
Signals of quark-gluon plasma
Abstract Production and observation of a quark-gluon plasma (QGP) is one of the most ambitious goals of the ultrarelativistic heavy ion experiments being carried out at CERN's super proton synchrotron (SPS) and at Brookhaven's Alternating Gradient Synchrotron (AGS). Future experiments at Brookhaven's Relativistic Heavy Ion Collider (RHIC) and at CERN's Large Hadron Collider (LHC) will give a new dimension to this search. In this review, the physics of QGP is presented with particular emphasis on its promising signatures existing in the literature. We hope that the present survey will lead us to identify some unambiguous signatures of QGP before the advent of RHIC and LHC experiments.
120728280
Rescattering effects in three-particle final-state reactions
The phenomenological aspect of single-pion production in ..pi../sup -/p interaction is explored by considering the final-state interactions in a rescattering box-diagram approach. We predict the qualitative and the quantitative features expected from our model in angular and momentum distributions of final pions. The preliminary data available so far appear to support our theoretical predictions.
35249306
Quantum violation of stochastic noncontextual hidden-variable theories.
We formulate stochastic noncontextual hidden-variable theories. In such theories the hidden state λ specifies not definite values, but expectation values A − (λ), ... of observables A, ... and noncontextuality means that A − (λ) is independent of which other commuting observables commuting with A are measured together with A. We show via Bell inequalities that such theories conflict with quantum theory and propose a two-photon experimental test. We also show that for a single particle of spin (2 n −1)/2, quantum violation of classical noncontextuality grows exponentially with n.
32129688
Systematics of preequilibrium contributions in (n,p) reactions at 14 MeV.
The existing up to data global data on angle integrated energy spectra (AIES) and energy integrated angular distributions (EIAD) of protons from ([ital n],[ital p]) reactions at 14 MeV nominal neutron energy have been analyzed to develop systematics in relative preequilibrium contributions (RPC). The experimental estimates of RPC were obtained either from asymmetric components of the extrapolated EIAD or from the analysis of AIES, by comparison with equilibrium contributions obtained from the Hauser-Feshbach model. The experimentally obtained RPC have been compared with those expected from recent Feschbach-Kerman-Koonin theory as extended by Kalbach [ital et] [ital al]. as well as with theoretical predictions by Brown and Muirhead. The mass number systematics of RPC manifest shell and even-odd effects. The fraction of the precompound nucleus decays obtained from RPC, using the Blann-Griffin model, is constant and small for [ital A][ge]72, and increases to about 1 for small [ital A]'s. The analysis with the Kalbach model yields the dependence of the level density parameters [ital a][sub 1] and [ital a][sub 2] on [ital A]; also values of [ital a][sub 1] and [ital a][sub 2] manifest prominent structures near closed shell nuclei. The values of [ital a][sub 1] for compound nucleus are systematically highermore » than [ital a][sub 2], for the residual nuclei by an amount much larger than expected by usual [ital A] dependence, indicating excitation energy dependence of the single particle level density [ital g]. The excitation energy dependence of [ital g] when explored in the light of Rosenzweig's positive power law, with parameters [ital n] and [ital k], reveals that for most cases 1.2[le][ital n][le]1.5, with no systematic dependence of [ital n] on [ital A], compared to reported theoretical values of [ital n][congruent]1.6 by Rosenzweig, and 0.8[le][ital k][le]3.8 with a trend of slow increase of [ital k] with [ital A].« less
26795671
Coulomb excitation of cadmium isotopes with protons.
Low-lying positive parity levels of the isotopes in natural cadmium were Coulomb excited with 2.7--4.2 MeV protons. Eight levels of /sup 111/Cd up to 1130.4 keV and four levels of /sup 113/Cd up to 680.5 keV excitation energy, and the first 2/sup +/ states in even-even isotopes (/sup 110,112,114,116/Cd) were excited. A 50 cm/sup 3/ Ge(Li) detector was used to measure the deexcitation gamma-ray yields. The 1130.4 keV level in /sup 111/Cd had not been investigated earlier through Coulomb excitation. Also the 245.4, 700, 754.9, 855.6, and 1020.7 keV levels in /sup 111/Cd, and the 316.1 keV level in /sup 113/Cd were Coulomb excited with protons for the first time. The reduced E2 transition probabilities B(E2), and partial half-lives T/sub 1/2/ (E2), for various levels were determined. The gamma-ray angular distributions were analyzed to deduce the E2/M1 mixing ratios (delta) for various transitions from the levels in /sup 111,113/Cd. The 700, 754.9, 855.6, and 1020.7 keV levels in /sup 111/Cd, and the 680.5 keV level in /sup 113/Cd have been assigned a spin value of (3/2)/sup +/, while the 1130.4 keV level in /sup 111/Cd has been assigned a spin of (5/2)/sup +/. The results have been compared with existingmore » theoretical and experimental data in the literature.« less
18313253
Distribution of the color fields around static quarks: Flux tube profiles.
We report detailed calculations of the profiles of energy and action densities in the quark-antiquark string in SU(2) lattice gauge theory. We conclude that at a {ital q}-{ital q}{vert_bar} separation {ital R}{approx_equal}1.0 fm we are beginning to see the asymptotic flux tube. By employing the Michael sum rules we further conclude that the peak energy density approaches a constant in {ital R}. {copyright} {ital 1995 The American Physical Society.}
42506674
Neutrino magnetic moment effects in neutrino nucleus reactions.
Some low energy neutrino nucleus reactions induced by neutrinos (antineutrinos) having a magnetic moment of the order of 10{sup {minus}9}{minus}10{sup {minus}10} Bohr magneton are studied. It is found that in the case of {sup 4}He, {sup 12}C, and {sup 16}O, the detection of very low energy scalar and isoscalar elastic and inelastic reactions induced by the isoscalar vector currents can provide a better limit on the neutrino magnetic moment.