119487881
ON THE RELATION BETWEEN MULTIPLICITY AND TRANSVERSE ENERGY IN HIGH ENERGY HADRON-HADRON AND NUCLEUS-NUCLEUS COLLISIONS
The relation between multiplicity and transverse energy in high energy h-h and A-A collisions is investigated using a Monte Carlo generator of nondiffractive processes. The width of multiplicity fluctuation D/ for fixed E⊥ is found to be small and approximately constant for a wide range of E⊥.
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.
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.
123369286
Local charge nonequilibrium and anomalous energy dependence of normalized moments in narrow rapidity windows
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.
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.
123064936
An interacting dark energy model in a non-flat universe
In this paper, an interacting dark energy model in a non-flat universe is studied, with taking interaction form $$C=\alpha H\rho _{de}$$C=αHρde. And in this study a property for the mysterious dark energy is aforehand assumed, i.e. its equation of state $$w_{\Lambda }=-1$$wΛ=-1. After several derivations, a power-law form of dark energy density is obtained $$\rho _{\Lambda } \propto a^{-\alpha }$$ρΛ∝a-α, here $$a$$a is the cosmic scale factor, $$\alpha $$α is a constant parameter introducing to describe the interaction strength and the evolution of dark energy. By comparing with the current cosmic observations, the combined constraints on the parameter $$\alpha $$α is investigated in a non-flat universe. For the used data they include: the Union2 data of type Ia supernova, the Hubble data at different redshifts including several new published datapoints, the baryon acoustic oscillation data, the cosmic microwave background data, and the observational data from cluster X-ray gas mass fraction. The constraint results on model parameters are $$\Omega _{K}=0.0024\,(\pm 0.0053)^{+0.0052+0.0105}_{-0.0052-0.0103}, \alpha =-0.030\,(\pm 0.042)^{+0.041+0.079}_{-0.042-0.085}$$ΩK=0.0024(±0.0053)-0.0052-0.0103+0.0052+0.0105,α=-0.030(±0.042)-0.042-0.085+0.041+0.079 and $$\Omega _{0m}=0.282\,(\pm 0.011)^{+0.011+0.023}_{-0.011-0.022}$$Ω0m=0.282(±0.011)-0.011-0.022+0.011+0.023. According to the constraint results, it is shown that small constraint values of $$\alpha $$α indicate that the strength of interaction is weak, and at $$1\sigma $$1σ confidence level the non-interacting cosmological constant model can not be excluded.
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.
118401402
Constraints on a decomposed dark fluid with constant adiabatic sound speed by jointing the geometry test and growth rate after Planck data
In this paper, a unified dark fluid with constant adiabatic sound speed is decomposed into cold dark matter interacting with vacuum energy. Based on a Markov-chain Monte Carlo method, we constrain this model by jointing the geometry and dynamical measurement. The geometry test includes cosmic microwave background radiation from Planck, baryon acoustic oscillation, and type-Ia supernovae; the dynamic measurement is $f{\ensuremath{\sigma}}_{8}(z)$ data points, which is obtained from the growth rate via redshift space distortion, and ${\ensuremath{\sigma}}_{8}(z)$ is the root-mean-square amplitude of the density contrast $\ensuremath{\delta}$ at the comoving $8{h}^{\ensuremath{-}1}\text{ }\text{ }\mathrm{Mpc}$ scale. The jointed constraint shows that $\ensuremath{\alpha}=0.00066{2}_{\ensuremath{-}0.000662}^{+0.000173}$ and ${\ensuremath{\alpha}}_{8}=0.82{4}_{\ensuremath{-}0.0166}^{+0.0128}$. The CMB and matter power spectra are both similar for the case of $\ensuremath{\alpha}=\text{mean}$ value and that of $\ensuremath{\alpha}=0$. However, the evolutionary curves of $f{\ensuremath{\sigma}}_{8}(z)$ are different. This means that, to some extent, the data points of the growth rate could break the degeneracy of the dark energy models.
118663304
THE DIAGNOSTICS AND POSSIBLE EVOLUTION IN ACTIVE GALACTIC NUCLEI ASSOCIATED WITH STARBURST GALAXIES
We present a large sample which contains 45 Seyfert 1 galaxies (Sy1s), 46 hidden broad-line region (HBLR) Seyfert 2 galaxies (Sy2s), 57 non-HBLR Sy2s, and 22 starburst galaxies to distinguish their properties and to seek the possible evolution of active galactic nuclei and starburst galaxies. We show that (1) using a plot of [O III] {lambda}5007/H{alpha} versus [N II] {lambda}6584/H{alpha} of standard optical spectral diagnostic diagrams, it is found that an equation can separate non-HBLR Sy2s and HBLR Sy2s well; (2) the emission-line ratios and both the combination of the ratios and polycyclic aromatic hydrocarbon strength are utilized effectively to separate starburst galaxies and Seyfert galaxies; (3) by comparing a number of quantities from the data, we confirm well the separations with statistics; (4) on the basis of statistics, we suggest that HBLR Sy2s may be the counterparts of Sy1s at edge-on orientation. In addition, we discuss the possibility of starburst galaxies evolving to non-HBLR Sy2s and HBLR Sy2s and then evolving to Sy1s based on the statistical analysis.
118725866
Magnetic-field effects on p-wave phase transition in Gauss–Bonnet gravity
In the probe limit, we study the holographic p-wave phase transition in the Gauss–Bonnet gravity via numerical and analytical methods. Concretely, we study the influences of the external magnetic field on the Maxwell complex vector model in the five-dimensional Gauss–Bonnet–AdS black hole and soliton backgrounds, respectively. For the two backgrounds, the results show that the magnetic field enhances the superconductor phase transition in the case of the lowest Landau level, while the increasing Gauss–Bonnet parameter always hinders the vector condensate. Moreover, the Maxwell complex vector model is a generalization of the SU(2) Yang–Mills model all the time. In addition, the analytical results backup the numerical results. Furthermore, this model might provide a holographic realization for the QCD vacuum instability.