Ising deconfinement transition between Feshbach-resonant superfluids

We investigate the phase diagram of bosons interacting via Feshbach-resonant pairing interactions in a one-dimensional lattice. Using large scale density matrix renormalization group and field theory techniques we explore the atomic and molecular correlations in this low-dimensional setting. We provide compelling evidence for an Ising deconfinement transition occurring between distinct superfluids and extract the Ising order parameter and correlation length of this unusual superfluid transition. This is supported by results for the entanglement entropy which reveal both the location of the transition and critical Ising degrees of freedom on the phase boundary.     

Correlations between multiplicities and average transverse momentum in the percolating color strings approach

Long range multiplicity-multiplicity, p_T²-multiplicity and p²_T- p²_T correlations are studied in the percolating color string picture under different assumptions of the dynamics of the string interaction. It is found that the strength of these correlations is rather insensitive to these assumptions; nor is it sensitive to the geometry of the fused string clusters that formed, the percolation phase transition in particular. Both multiplicity-multiplicity and p_T²-multiplicity correlations are found to scale and depend only on the string density. p_T²-multiplicity correlations, which are absent in the independent string picture, are found to be of the order of 10% for central heavy ion collisions and can serve as a clear signature of string fusion. In contrast p²_T- p²_T correlations turned out to be inversely proportional to the number of strings and therefore to be very small for realistic collisions.Received: 4 July 2003, Revised: 12 September 2003, Published online: 18 December 2003     

The gluon condensate and the deconfinement transition

The gluon condensate of dimension 4 is shown to stay unchanged through the deconfining phase transition.     

On the deconfinement phase transition in the resonance gas

We obtain the constraints on the governing parameters of the dense hadronic gas model at the critical temperature and propose quasiuniversal ratios of the thermodynamic quantities. The possible appearance of thermodynamic instability is discussed. Pis’ma Zh. éksp. Teor. Fiz. 63, No. 7, 487–491 (10 April 1996) Alexander von Humboldt Fellow. Published in English in the original Russian journal. Edited by Steve Torstveit.     

Thermodynamics of a single bag and quark deconfinement phase transition

We present-in our opinion conclusive-evidence that the fermion number induced by the coupling to a chiral hedgehog in 3+1 dimensions is zero.     

Correlations and self-consistency in pion scattering (I)

We propose a new approach for calculating higher-order effects in pion multiple scattering. Our theory includes nucleon-nucleon correlations and incorporates the idea of self-consistency. We examine the theory analytically in the case of nonoverlapping scatterers and find that : (i) higher-order terms are more moderate in size than found previously; (ii) the Kisslinger anomaly cannot occur ; and (iii) the pion mean free path at resonance is comparable to the interparticle spacing at high density. The ideas are developed within the framework of the Foldy-Walecka theory but are applicable in more comprehensive theories.     

Hydrodynamic modeling of deconfinement phase transition in nuclear collision

The (3 + 1)-dimensional ideal hydrodynamics is used to simulate collisions of gold nuclei with bombarding energies from 1 to 160 GeV per nucleon. The initial state is represented by two cold Lorentzboosted nuclei. Two equations of state: with and without the deconfinement phase transition are used. We have investigated dynamical trajectories of compressed baryon-rich matter as functions of various thermodynamical variables. The parameters of collective flow and hadronic spectra are calculated. It is shown that presence of the deconfinement phase transition leads to increase of the elliptic flow and to flattening of proton rapidity distributions.     

Signatures of the deconfinement transition in nucleus-nucleus collisions at the CERN SPS

The energy dependence of hadron production in relativistic nucleus-nucleus collisions reveals anomalies-kink, horn, and step. They have been predicted as the signals of the deconfinement phase transition and observed recently by the NA49 Collaboration in Pb + Pb collisions at the CERN SPS. This indicates the onset of deconfinement in nucleus-nucleus collisions at about 30 A GeV. The text was submitted by the author in English.     

High spin states and neutron multiplicities after pion capture in181Ta and209Bi

The absorption of stoppedπ ^? in¹⁸¹Ta and²⁰⁹Bi has been investigated by studying prompt and delayedγ-ray spectra. Absolute cross-sections for the yield of isotopes per capturedπ ^? in (π ^?, xn) reactions, as well as the relative probability of populating nuclear states of different spins have been measured for the hafnium and lead isotopes, respectively. A spin as high as 20 has been observed in the production of²⁰⁴Pb. The ground-state rotational bands of the hafnium isotopes are excited to spin values up to 16. Neutron multiplicities as large as 15 have been observed for both targets. A neutron multiplicity of ?8 is most probable for both tantalum and bismuth targets. The strong interaction monopole energy shift? ₀ and widthΓ ⁰ for the 4f level are found to beε ₀(¹⁸¹Ta)=540±100eV; ?₀(²⁰⁹Bi)=1790±150 eV;Γ ₀(¹⁸¹Ta)=225±57 eV;Γ ₀(²⁰⁹Bi) =1166±70 eV. The quadrupole moments, determined from the hyperfine splitting of the 4f pionic atom level, areQ=3.30±0.06b andQ=}-0.50±0.08b for¹⁸¹Ta and²⁰⁹Bi, respectively.     

Chiral transition and deconfinement transition in QCD with the highly improved staggered quark (HISQ) action

We report preliminary results on the chiral and deconfinement aspects of the QCD transition at finite temperature using the Highly Improved Staggered Quark (HISQ) action on lattices with temporal extent of N _τ = 6 and 8. The chiral aspects of the transition are studied in terms of quark condensates and the disconnected chiral susceptibility. We study the deconfinement transition in terms of the strange quark number susceptibility and the renormalized Polyakov loop. We find reasonably good agreement between our results and the recent continuum extrapolated results obtained with the stout staggered quark action.     

Finite size effects on bag thermodynamics and quark-gluon deconfinement phase transition

We have investigated the effects of finite size corrections (surface and curvature) to the single particle density of states on various thermodynamic quantities of massless quarks and gluons confined in a spherical cavity. The chemical potential zero and non-zero both the cases are studied. Ignoring the surface term which seems much less important than the curvature term, the problem can be studied analytically in the case of zero chemical potential. We find a first order deconfinement phase transition contrary to the second order in absence of the curvature term. Furthermore, the values of the transition temperature,T _s in the infinite volume limit and the critical temperatureT _c >T _s , beyond which hadrons cease to exist, are in conformity with our earlier studies.     

Fluctuations and correlations as a signal of deconfinement

Event-by-event fluctuations of the K/??, K/p, and p/?? ratio in central AA collisions have been studied for SPS and RHIC energies. The Hadron-String-Dynamical transport approach (HSD) can qualitatively reproduce the measured excitation function for the K/?? ratio fluctuations. The di-jet azimuthal correlations also have been investigated within the HSD model. We found that the suppression of the away-side jet in the hadronic mediumis not enough to explain the experimental data from RHIC. The additional suppression should be attributed to a quark-gluon plasma produced in heavy-ion collisions.     

Model of deconfinement phase transition in baryonic quark-gluon bag system

A model of phase transition between baryonic hadron and quark-gluon matter is elaborated. The spectrum of baryonic colourless bags is found. It is shown that the constraint of bag colourlessness is decisive for the phase transition to be realized.