121684801
THE VARIABLE GENERALIZED CHAPLYGIN GAS MODEL WITH INTERACTION
In this paper a variable generalized Chaplygin gas (VGCG) proposal for unification of dark matter and dark energy is considered, in which dark energy interacts with dark matter. The equation of state of the VGCG is given by p = -A0a-n/ρα, where a is the scale factor. By calculations some cosmological quantities such as density parameters of baryons, dark matter and dark energy as well as the deceleration parameter are all obtained. Furthermore, the transition from deceleration to acceleration is described and the interaction between dark energy and dark matter is considered in this model. We find the behavior of VGCG is similar to dust-like matter at early times and will be quintessence or phantom at late stage. In addition the evolution trajectory of the VGCG model in the statefinder parameter s-r plane is plotted and the discrimination between this scenario and the generalized Chaplygin gas (GCG) model is illustrated.
204012276
Evolution of Holographic Dark Energy in Interacting Modified Chaplygin Gas Model
We investigate the modified Chaplygin gas (MCG) with interaction between holographic dark energy proposed by Li and dark matter. In this model, evolution of the universe is described in detail, which is from deceleration to acceleration. Specifically, the evolutions of related cosmological quantities such as density parameter, the equation of state of holographic dark energy, deceleration parameter and transition redshift are discussed. Moreover, we also give their present values which are consistent with the lately observations. Furthermore, the results given by us show such a model can accommodate a transition of the dark energy from a normal state wX > – 1 to wX < – 1 phantom regimes.
122566445
CONSTRAINT ON THE KINEMATICAL AND DYNAMICAL MODEL FROM THE LATEST OBSERVATIONAL DATA
The kinematical model j(z) = j0 and dynamical model wde(z) = w0, are constrained from the latest observational data: Union2 data including 557 type Ia supernovae (SNIa), 15 observational Hubble data (OHD), baryon acoustic oscillation (BAO) data from Sloan Digital Sky Survey (SDSS) and Two-degree Field Galaxy Redshift Survey (2dFGRS) and CMB data from seven-year WMAP. We get the current values of deceleration parameter q0, jerk parameter j0, dimensionless matter density Ωm, equation of state for dark energy w0 and transition redshift zT. Furthermore, it is shown that for both kinematical and dynamical models, the constraint results support for the cosmic concordance model, ΛCDM.
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.
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.
121574004
The double coupling of the Ashtekar gravitational field to the Dirac spinoral fields
By introducing the double spacetime manifold, the double gamma matrices and Dirac spinors, the action of the Dirac spinoral fields is doubled. Furthermore, the double coupling of the Dirac fields to the Ashtekar gravitational fields is studied.
120731900
On the random cascading model study of anomalous scaling in multiparticle production with continuously diminishing scale
The anomalous scaling of factorial moments with continuously diminishing scale is studied using a random cascading model. It is shown that the model currently used have the property of anomalous scaling only for descrete values of elementary cell size. A revised model is proposed which can give good scaling property also for continuously varying scale. It turns out that the strip integral has good scaling property provided the integral regions are chosen correctly, and that this property is insensitive to the concrete way of self-similar subdivision of phase space in the models.
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.
118408012
Measurement of Cosmic Ray Flux in China JinPing underground Laboratory
China JinPing underground Laboratory (CJPL) is the deepest underground laboratory presently running in the world. In such a deep underground laboratory, the cosmic ray flux is a very important and necessary parameter for rare event experiments. A plastic scintillator telescope system has been set up to measure the cosmic ray flux. The performance of the telescope system has been studied using the cosmic ray on the ground laboratory near CJPL. Based on the underground experimental data taken from November 2010 to December 2011 in CJPL, which has effective live time of 171 days, the cosmic ray muon flux in CJPL is measured to be (2.0+-0.4)*10^(-10)/(cm^2)/(s). The ultra-low cosmic ray background guarantees CJPL's ideal environment for dark matter experiment.
8561645
Parton branching in the color mutation model
The soft production problem in hadronic collisions as described in the eikonal color mutation branching model is improved in the way that the initial parton distribution is treated. Furry branching of the partons is considered as a means of describing the nonperturbative process of parton reproduction in the soft interaction. The values of all the moments, {l_angle}n{r_angle} and C{sub q}, for q=2,{hor_ellipsis},5, as well as their energy dependences, can be correctly determined by the use of only two parameters. {copyright} {ital 1999} {ital The American Physical Society}
123063233
ON THE STABILITY OF RAPIDITY GAP ANALYSIS
It is argued that the newly introduced moments of rapidity gaps for the event-by-event fluctuations depends on the number of events and multiplicity. The interesting ones are unstable under ISR energies of h–h collisions. The instability is well improved when multiplicity increases.