A Model-Independent Discussion of Quark Number Density and Quark Condensate at Zero Temperature and Finite Quark Chemical Potential

Generally speaking, the quark propagator is dependent on the quark chemical potential in the dense quantum chromodynamics （QCD）. By means of the generating functional method, we prove that the quark propagator actually depends on p4 ＋ iμ from the first principle of QCD. The relation between quark number density and quark condensate is discussed by analyzing their singularities. It is concluded that the quark number density has some singularities at certain # when T = 0, and the variations of the quark number density as well as the quark condensate are located at the same point. In other words, at a certain # the quark number density turns to nonzero, while the quark condensate begins to decrease from its vacuum value.

Further investigation of the model-independent probe of heavy neutral Higgs bosons at LHC Run 2

In one of our previous papers,we provided general,effective Higgs interactions for the lightest Higgs boson h（SM-like） and a heavier neutral Higgs boson H based on the effective Lagrangian formulation up to the dim-6 interactions,and then proposed two sensitive processes for probing H.We showed in several examples that the resonance peak of H and its dim-6 effective coupling constants（ECC） can be detected at LHC Run 2 with reasonable integrated luminosity.In this paper,we further perform a more thorough study of the most sensitive process,pp →VH^＊→VVV,providing information about the relations between the 1σ,3σ,5σ statistical significance and the corresponding ranges of the Higgs ECC for an integrated luminosity of 100 fb^-1.These results have two useful applications in LHC Run 2：（A） realizing the experimental determination of the ECC in the dim-6 interactions if H is found and,（B） obtaining the theoretical exclusion bounds if H is not found.Some alternative processes sensitive for certain ranges of the ECC are also analyzed.

Null test for cosmic curvature using Gaussian process

The cosmic curvature Ω_(K,0),which determines the spatial geometry of the universe,is an important parameter in modern cosmology.Any deviation from Ω_(K,0)=0 would have a profound impact on the primordial inflation paradigm and fundamental physics.In this work,we adopt a cosmological model-independent method to test whether Ω_(K,0) deviates from zero.We use the Gaussian process to reconstruct the reduced Hubble parameter E(z)and the derivative of the distance D'(z)from observational data and then determine Ω_(K,0) with a null test relation.The cosmic chronometer(CC)Hubble data,baryon acoustic oscillation(BAO)Hubble data,and supernovae Pantheon sample are considered.Our result is consistent with a spatially flat universe within the domain of reconstruction 0<z<2.3,at the 1σ confidence level.In the redshift interval 0<z<1,the result favors a flat universe,while at z>1,it tends to favor a closed universe.In this sense,there is still a possibility for a closed universe.We also carry out the null test of the cosmic curvature at 0<z<4.5 using the simulated gravitational wave standard sirens,CC+BAO,and redshift drift Hubble data.The result indicates that in the future,with the synergy of multiple highquality observations,we can tightly constrain the spatial geometry or exclude the flat universe.

RMB Exchange Market Pressure and Central Bank Exchange Market Intervention

The present paper uses the model-dependent and the modeL independent approach to measure the RMB exchange market pressure （EMP） and the central bank＇s intervention using monthly data from January 1999 to June 2008. It is determined that the RMB has been under great appreciation pressure over the past decade. However, the pressure has been weakening since 2005. The two approaches provide significantly different results in terms of the estimated RMB EMP indices and the estimated central bank＇s interventions. The differences may lead to different predietions of potential currency crises. According to the estimation of the RMB EMP, and based on the model-independent approach, the paper shows that China has been under threat of an appreciation currency crisis since 2008. Therefore, China should adopt a moreflexible exchange rate regime to prevent a potential crisis.