18736676
Yano-Koonin-Podgoretskii parametrization of the HBT correlator: A Numerical study
The Yano-Koonin-Podgoretski˘ ı (YKP) parametrisation of Hanbury-Brown/Twiss (HBT) two-particle correlation functions opens new strategies for extracting the emission duration and testing the longitudinal expansion in heavy-ion collisions. Based on the recently derived model-independent expressions , we present a detailed parameter study of the YKP fit parameters for a hydrodynamic finite expanding source model of heavy-ion collisions. Our study supports the clean spatio-temporal interpretation of the three YKP radius parameters as longitudinal extension, transverse extension and emission duration of the source in the YKP Lorentz frame. This frame is specified by the fourth fit parameter, the Yano-Koonin velocity which describes to a good approximation the velocity of the fluid element with highest emissivity and allows to test for the longitudinal expansion of the source. Deviations from this interpretation of the YKP parameters are quantitatively discussed and found to be generically small.
123369286
Local charge nonequilibrium and anomalous energy dependence of normalized moments in narrow rapidity windows
16991538
On the Dominance of Statistical Fluctuation in the Factorial-Moment Study of Chaos in Low Multiplicity Events of High Energy Collisions
It is shown using Monte Carlo simulation that for low multiplicity events the single-event factorial moments are saturated by the statistical fluctuations. The diverse of the event-space moments $C_{p,q}$ of single-event moments with the diminishing of phase space scale, called ``erraticity'', observed in experiment can readily be reproduced by a flat probability distribution with only statistical fluctuations and therefore does not indicate the existence of chaos as suggested. The possibility of studying chaos in high multiplicity events using erraticity analysis is discussed.
120866499
FRACTALITY IN ELEMENTARY COLLISIONS
Different fractality in hadron–hadron and e+e- collisions and its experimental observation are reviewed. The discussions on related underlying dynamics are presented.
116833066
Locating the critical point of QCD phase transition by finite-size scaling
It is pointed out that in relativistic heavy ion collisions, critical related observable in the vicinity of critical point should follow finite-size scaling. The methods of finding and locating critical point are established for the first time by finite-size scaling and its critical characteristics, in particular, the fixed-point and straight-line behavior. As an application of the method, the critical behavior at RHIC data is demonstrated.
118547741
Statistical and dynamical fluctuations of Binder ratios in heavy ion collisions
Higher moments of the net-proton Binder ratio, which is suggested to be a good observation to locate the QCD critical point, is measured in relativistic heavy ion collisions. We first estimate the effect of statistical fluctuations of the third- and fourth-order Binder ratios. Then the dynamical Binder ratio is proposed and investigated in both transport and statistical models. The energy dependence of dynamical Binder ratios with different system sizes at RHIC beam scan energies is presented and discussed.
119275903
Lifshitz effects on holographic p-wave superfluid
Abstract In the probe limit, we numerically build a holographic p -wave superfluid model in the four-dimensional Lifshitz black hole coupled to a Maxwell-complex vector field. We observe the rich phase structure and find that the Lifshitz dynamical exponent z contributes evidently to the effective mass of the matter field and dimension of the gravitational background. Concretely, we obtain that the Cave of Winds appeared only in the five-dimensional anti-de Sitter (AdS) spacetime, and the increasing z hinders not only the condensate but also the appearance of the first-order phase transition. Furthermore, our results agree with the Ginzburg–Landau results near the critical temperature. In addition, the previous AdS superfluid model is generalized to the Lifshitz spacetime.
121493612
GEOMETRICAL DIAGNOSTICS FOR THE NEW AGEGRAPHIC DARK ENERGY MODEL WITH INTERACTION
In this paper, on the basis of Ref. 24 we will further study the new agegraphic dark energy (NADE) model with interaction term Γ = 3b2Hρc. Concretely, not only can the evolutions of some related cosmological quantities be described, but also the two geometrical diagnostic approaches are performed to this model, i.e. statefinder and Om diagnostics. By illustrating the evolutionary trajectories in r-s, r-q, w'-w and Om planes, we find that the constant n and coupling intensity b2 play very important roles in the NADE model, and the Om curves of the NADE model are more sensitive to the constants than ones of the OADE model. In addition, we also plot the LCDM horizonal lines in Om diagrams, and show the discrimination among the NADE, OADE and LCDM models.
119216015
More on QCD ghost dark energy
The difference between the vacuum energy of quantum fields in Minkowski space and in a Friedmann-Robertson-Walker universe might be related to the observed dark energy. The vacuum energy of the Veneziano ghost field introduced to solve the U(1)(A) problem in QCD is of the form H + O(H-2). Based on this, we study the dynamical evolution of a phenomenological dark energy model whose energy density is of the form alpha H + beta H-2. In this model, the universe approaches a de Sitter phase at late times. We fit the model with current observational data, including SnIa, BAO, CMB, BBN, the Hubble parameter, and the growth rate of matter perturbation. It shows that the universe begins to accelerate at redshift z similar to 0.75, and this model is consistent with current data. In particular, this model fits the data of the growth factor well as the Lambda CDM model.
119284084
Reconstruction of new holographic scalar field models of dark energy in Brans-Dicke universe
Motivated by the work: K. Karami and J. Fehri, Phys. Lett. B684, 61 (2010) and A. Sheykhi, Phys. Lett. B681, 205 (2009), we generalize their work to the new holographic dark energy model with in the framework of Brans–Dicke cosmology. Concretely, we study the correspondence between the quintessence, tachyon, K-essence, dilaton scalar field and Chaplygin gas model with the new holographic dark energy model in the non-flat Brans–Dicke universe. Furthermore, we reconstruct the potentials and dynamics for these models. By analysis we can show that for new holographic quintessence and Chaplygin gas models, if the related parameters to the potentials satisfy some constraints, the accelerated expansion can be achieved in Brans–Dicke cosmology. In particular, the counterparts of fields and potentials in general relativity can describe accelerated expansion of the universe. It is worth stressing that not only can we give some new results in the framework of Brans–Dicke cosmology, but also the previous results of the new holographic dark energy in Einstein gravity can be included as special cases given by us.
122648799
STUDY ON A UNIFIED MODEL OF DARK MATTER AND DARK ENERGY FROM DBI THEORY
In this paper, we study a unified model of dark matter and dark energy obtained from Dirac–Born–Infeld (DBI) action in string theory. Two accelerated expansions in universe can be unified in this action. By using the Markov Chain Monte Carlo method, we fit the current observational data to constrain the model parameters in this unified model, where various density parameters as model parameters are included, and their constraint values are: , , and . In addition, the Hubble constant and cosmic age are and (Gyr), respectively. According to the constraint results on model parameters we discuss the evolutions of some cosmological quantities in structure formation, such as the density contrast and the growth variable. At last, the evolution of geometrical quantity is studied to distinguish the unified models of dark sectors with the cosmological constant model. It is shown that this unified model of dark matter and dark energy is attractive to interpret the accelerating universe.