Deep inelastic scattering with proton target in the presence of gluon condensation using holography

We study the deep inelastic scattering(DIS)of a proton-targeted lepton in the presence of gluon condensation using gauge/gravity duality.We use a modified AdS5background where the modification parameter c corresponds to the gluon condensation in the boundary theory.First,by examining the electromagnetic field,we establish that a non-zero c can increase field magnitude.Our aim is to obtain the acceptable value of c for this scattering.Our method is based on setting the mass of the proton as an eigenvalue of the baryonic state equations of the DIS to find the acceptable value of the parameter c on the other side of the equations.Therefore,in the second step,we calculate wave function equations for the baryonic states where the mass of the proton target requires a value contribution of c as c=0.0120 GeV4.Proceeding with the electromagnetic field and baryonic states,we derive the holographic interaction action related to the amplitude of the scattering.Finally,we compute the corresponding structure functions numerically as functions of x and q,which are Bj?rken variables and the lepton momentum transfers,respectively.Comparing the Jlab Hall C data with our theoretical calculations,our results are acceptable.

Gluon condensate in color superconductivity

In color superconductor the gluon condensate drops down at moderate density but goes up at high density and can even exceed its vacuum value when the density is high enough.

Quark and gluon condensates in nuclear matter with Brown-Rho scaling

Quark and gluon condensates in nuclear matter are investigated in a density-dependent relativistic mean-field theory. The in-medium quark condensate decreases rapidly as the density of nu-clear matter increases, if the Brown-Rho scaling is included. The decrease in the in-medium quark condensate with the nuclear matter density is consistent with the result predicted by the partial chiral symmetry restoration. The gluon condensate and the influence of the strange quark contents on the gluon condensate in nuclear matter are discussed.

Electric and magnetic screenings of gluons in a model with a dimension-2 gluon condensate

Electric and magnetic screenings of the thermal gluons are studied by using the background expansion method in a gluodynamic model with gauge invariant dimension-2 gluon condensate at zero momentum. At low temperature, the electric and magnetic gluons are degenerate. With the increase of temperature, it is found that the electric and magnetic gluons start to split at certain temperature T0. The electric screening mass changes rapidly with temperature when T 〉 T0, and the Polyakov loop expectation value rises sharply around T0 from zero in the vacuum to a value around 0.8 at high temperature. This suggests that the color electric deconfinement phase transition is driven by electric gluons. It is also observed that the magnetic screening mass keeps almost the same as its vacuum value, which manifests that the magnetic gluons remain confined. Both the screening masses and the Polyakov loop results are qualitatively in agreement with the Lattice calculations.

Temperature dependence of quarks and gluon vacuum condensate in the Dyson-Schwinger Equations at finite temperature

Based on the Dyson-Schwinger Equations （DSEs）, the two-quark vacuum condensate, the four-quark vacuum condensate, and the quark gluon mixed vacuum condensate in the non-perturbative QCD vacuum state are investigated by solving the DSEs with rainbow truncation at zero- and finite- temperature, respectively. These condensates are important input parameters in QCD sum rule with zero and finite temperature, and in studying hadron physics, as well as predicting the quark mean squared momentum rn02- also called quark virtuality in the QCD vacuum state. The present calculated results show that these physical quantities are almost independent of the temperature below the critical point temperature Tc=131 MeV, and above Tc the chiral symmetry is restored. For comparison we calculate the temperature dependence of the ＂in-hadron condensate＂ for pion. At the same time, we also calculate the ratio of the quark gluon mixed vacuum condensate to the two-quark vacuum condensate by using these condensates, and the unknown quark mean squared momentum in the QCD vacuum state has been obtained. The results show that the ratio m2/0（T） is almost fiat in the temperature region from 0 to To, although there are drastic changes of the quark vacuum condensate and the quark gluon mixed vacuum condensate at the region. Our predicted ratio comes out to be m2/0（T）=2.41 GeV2 at the Chiral limit, which is consistent with other theory model predictions, and strongly indicates the significance that the quark gluon mixed vacuum condensate has played in the virtuality calculations.

A comparison of condensate mass of QCD vacuum between Wilson line approach and Schwinger effect

We studied the condensate mass of QCD vacuum through the duality approach via dilaton wall back-ground in the presence of the parameter c,which represents the condensation in a holographic set up.First,fromWilson line calculation,we found m_(0)^(2)(i.e.,the condensate parameter in mixed non-local condensation),whose beha-vior mimics that of QCD.The value of m_(0)^(2)that we found by this approach is in agreement with QCD data.Second we considered the produced mass m via the Schwinger effect mechanism in the presence of the parameter c.We show that vacuum condensation generally contributes the mass dominantly and that the produced mass via Schwing.er effect is suppressed by m_(0).