Search results for "Strange matter"
showing 10 items of 20 documents
Cascade simulation of ultrarelativistic collisions
1988
The dynamics of hot matter produced in ultrarelativistic heavy-ion collisions is studied with a cascade simulation. We model the putative quark-gluon plasma with independent globs of high-density matter. The hadronic phase is treated by explicit tracking of pion coordinates. We find that the pions make 0--2 collisions with globs and 1--3 collisions with other pions, under conditions expected for heavy ions at collider energies. The entropy increases by about 20% during the phase transition. The transverse momentum in the final state is almost entirely due to the momentum with which pions are emitted from the globs, except at extremely high densities where the hydrodynamic expansion of the p…
The half-skyrmion phase in a chiral-quark model
2013
The Chiral Dilaton Model, where baryons arise as non-topological solitons built from the interaction of quarks and chiral mesons, shows in the high density low temperature regime a two phase scenario in the nuclear matter phase diagram. Dense soliton matter described by the Wigner–Seitz approximation generates a periodic potential in terms of the sigma and pion fields that leads to the formation of a band structure. The analysis up to three times nuclear matter density shows that soliton matter undergoes two separate phase transitions: a delocalization of the baryon number density leading to B=1/2B=1/2 structures, as in skyrmion matter, at moderate densities, and quark deconfinement at larg…
Studies of the hydrodynamic evolution of matter produced in fluctuations inp¯pcollisions and in ultrarelativistic nuclear collisions
1986
In this first paper of a series of two, we present a comprehensive study of the hydrodynamic evolution of matter produced in the central region of ultrarelativistic heavy-ion collisions and in high-multiplicity fluctuations of p-barp-italic collisions. We shall begin with a discussion of the limits of the applicability of a perfect-fluid hydrodynamic description of high-energy collisions. A simple bag-model equation of state is argued to have qualitative and semiquantitative features expected from lattice gauge theory and present theoretical understanding. We also discuss the boundary conditions for the perfect-fluid hydrodynamic equations, and what classes of simple events would correspond…
ASYMMETRIES IN POLARIZED ELECTRON SCATTERING AND THE STRANGENESS CONTENT OF THE NUCLEON
2009
In the viewpoint of QCD, the nucleon is made up of constituent quarks, sea quarks and gluons. Concerning the quark sea, also strange quarks can contribute to the nucleon properties. Parity violating electron scattering offers a tool to investigate the strange quark contribution to the nucleon form factors. The measurements of different experiments are discussed and the recent results from the A4 collaboration at MAMI is presented. Altogether the existing data allow to give constraints on the strangeness contribution.
Quarks in nuclei
1992
We review some properties of Quantum Chromodynamics, the theory of the hadronic interactions, which serve as guidelines to introduce low energy models of hadron structure. Among these we shall center our attention in the non relativistic quark model and the topological bag model. We present some of their applications to actual problems in experimental and theoretical nuclear physics. In particular we discuss exotic nuclei, quark matter, deep inelastic scattering, proton spin,... and their relation to such phenomena as quark Pauli blocking, strangeness enhancement, nuclear structure functions, bosonization,...
NNLO Unquenched Calculation of the b Quark Mass
2000
By combining the first unquenched lattice computation of the B-meson binding energy and the two-loop contribution to the lattice HQET residual mass, we determine the (\bar{{MS}}) (b)-quark mass, (\bar{m}_{b}(\bar{m}_{b})). The inclusion of the two-loop corrections is essential to extract (\bar{m}_{b}(\bar{m}_{b})) with a precision of ({\cal O}(\Lambda^{2}_{QCD}/m_{b})), which is the uncertainty due to the renormalon singularities in the perturbative series of the residual mass. Our best estimate is (\bar{m}_{b}(\bar{m}_{b}) = (4.26 \pm 0.09) {\rm GeV}), where we have combined the different errors in quadrature. A detailed discussion of the systematic errors contributing to the final number …
Search for strange matter by Rutherford backscattering
1989
According to a number of suggestions, stable strange matter could exist in the form of supermassive nuclei (or 'strange nuggets')1,2. In contrast to ordinary nuclei, which contain only 'up' and 'down' quarks, a piece of strange matter should comprise a mixture of 'up', 'down' and 'strange' quarks in roughly equal proportions. Small amounts of strange matter could have survived from the early stages of the Universe1. Alternatively, strange matter might reach the Earth as a flux of strange nuggets produced in collisions of neutron stars3. Limits to the cosmic flux of strange nuggets with masses in the range from 10−4 to 250 g have been obtained in a search for light produced by the nuggets in…
Probing the chiral regime of Nf=2 QCD with mixed actions
2011
17 páginas, 15 figuras, 9 tablas.-- El Pdf es la versión pre-print del artículo: arXiv:1008.1870v2
Rapidity distributions of dileptons from a hadronizing quark-gluon plasma
1994
It has been predicted that dilepton production may be used as a quark-gluon plasma probe. We calculate the rapidity distributions of thermal dileptons produced by an evolving quark-gluon plasma assuming a longitudinal scaling expansion with initial conditions locally determined from the hadronic rapidity density. These distributions are compared with Drell-Yan production and semileptonic charm decays at invariant mass $M = 2$, 4, and 6 GeV.
Shock phenomena in baryonless strongly interacting matter.
1987
Shock phenomena associated with the quark-to-hadron matter phase transition are studied using the concept of adiabats. To allow for an analysis of a medium with vanishing baryon density, the shock and Poisson adiabats are formulated in terms of hydrodynamic fluxes, rather than only thermodynamic variables. The bag-model equation of state is used to describe the phase transition. It is shown that deflagrations from the quark phase above the critical temperature and strong detonations from the supercooled quark phase to the superheated hadron phase are unlikely. Instead the possibility of weak condensation detonations from the supercooled quark phase to a mixed phase is indicated. Strong deto…