No Arabic abstract
In this paper we derived in QCD the BFKL linear, inhomogeneous equation for the factorial moments of multiplicity distribution($M_k$) from LMM equation. In particular, the equation for the average multiplicity of the color-singlet dipoles($N$) turns out to be the homogeneous BFKL while $M_k propto N^k$ at small $x$. Second, using the diffusion approximation for the BFKL kernel we show that the factorial moments are equal to: $M_k=k!N( N-1)^{k-1}$ which leads to the multiplicity distribution:$ frac{sigma_n}{sigma_{in}}=frac{1}{N} ( frac{N,-,1}{N})^{n - 1}$. We also suggest a procedure for finding corrections to this multiplicity distribution which will be useful for descriptions of the experimental data.
We show that the recently developed Hamiltonian theory for high energy evolution in QCD in the dilute regime and in the presence of Bremsstrahlung is consistent with the color dipole picture in the limit where the number of colors N_c is large. The color dipoles are quark-antiquark pairs which can radiate arbitrarily many soft gluons, and the evolution consists in the splitting of any such a dipole into two. We construct the color glass weight function of an onium as a superposition of color dipoles, each represented by a pair of Wilson lines. We show that the action of the Bremsstrahlung Hamiltonian on this weight function and in the large-N_c limit generates the evolution expected from the dipole picture. We construct the dipole number operator in the Hamiltonian theory and deduce the evolution equations for the dipole densities, which are again consistent with the dipole picture. We argue that the Bremsstrahlung effects beyond two gluon emission per dipole are irrelevant for the calculation of scattering amplitudes at high energy.
The multiplicity distribution of the gluons produced at the high energy is evaluated in BFKL approach. The distribution has Poisson form that can explain experimentally observed KNO scaling.
In this proceedings contribution, we discuss recent developments in the perturbative determination of the Equation of State of dense quark matter, relevant for the microscopic description of neutron star cores. First, we introduce the current state of the art in the problem, both at zero and small temperatures, and then present results from two recent perturbative studies that pave the way towards extending the EoS to higher orders in perturbation theory.
Analytical formula for multiplicity distribution is derived in the QO approach, where chaotic and coherent fields are contained. Observed charged multiplicity distributions in Au+Au collisions at $sqrt{s}=200$ AGeV and in pp collisions at $sqrt{s}=900$ GeV are analyzed by the formula. Chaoticity parameters in the inclusive events estimated from the analysis of multiplicity distributions are compared with those estimated from the analysis of observed two-particle inclusive identical particle correlations.
In this paper we propose an approach which demonstrates the dependence of quarkoni production on the multiplicity of the accompanying hadrons. Our approach is based on the three gluons fusion mechanism, without assuming the multiplicity dependence of the saturation scale. We show, that we describe the experimental data, which has a dependence that is much steeper than the multiplicity of the hadrons.