相关论文: Comments on high-energy total cross sections in QC…
When hadrons scatter at high energies, strong color fields, whose dynamics is described by quantum chromodynamics (QCD), are generated at the interaction point. If one represents these fields in terms of partons (quarks and gluons), the…
We derive an effective action combining chiral and heavy quark symmetry, using approximate bosonization techniques of QCD. We explicitly show that the heavy-quark limit is compatible with the large $N_c$ (number of color) limit in the meson…
We present a program to calculate the total cross section for top-quark pair production in hadronic collisions. The program takes into account recent theoretical developments such as approximate next-to-next-to-leading order perturbative…
The behaviour of the topological susceptibility in QCD with two colours and 8 flavours of quarks is studied at nonzero temperature on the lattice across the finite density transition. It is shown that its signal drops at a (pseudo-)critical…
We compute the total cross section of a heavy quarkonium on a hadron target in leading twist QCD, including target mass corrections. Our method relies on the analytical continuation of the operator product expansion of the scattering…
We calculate electric and baryonic charge fluctuations on the lattice. Results have been obtained with the highly improved staggered quark action (HISQ) and almost physical quark masses on lattices with spacial extent of $N_\tau=6,8,12$.…
The analytic continuation of the operator product expansion of the scattering amplitude allows to compute the heavy-quarkonium hadron total cross section. The energy dependence of the Upsilon and Upsilon' cross sections with a proton is…
The high energy limit of QCD is controlled by the small-$x$ part of a hadron wavefunction. We argue that this part is universal to all hadrons and is composed of a new form of matter: a Colored Glass Condensate. This matter is weakly…
We demonstrate that the form factors of local operators between a heavy meson state (like the~$B$) and a light pseudoscalar state (like the pion) are given exactly by a single pole form in the combined heavy quark, large $N_c$ (number of…
We study the properties of QCD at high baryon density in a finite volume where color superconductivity occurs. We derive exact sum rules for complex eigenvalues of the Dirac operator at finite chemical potential, and show that the Dirac…
We follow our previous paper on possible cosmological variation of weak scale (quark masses) and strong scale, inspired by data on cosmological variation of the electromagnetic fine structure constant from distant quasar (QSO) absorption…
We study the electromagnetic on-shell form factor of quarks in massless perturbative QCD. We derive the complete pole part in dimensional regularization at three loops, and extend the resummation of the form factor to the…
A previously successful model for purely hadronic total cross-sections, based on QCD minijets and soft-gluon resummation, is here applied to the total photoproduction cross section. We find that our model in the gamma p case predicts a rise…
The total cross section for the production of massive quarks in electron positron annihilation can be predicted in perturbative QCD. After expansion in m^2/s the quartic terms, i.e. those proportional to m^4/s^2, are calculated up to order…
The heavy quark system is an excellent probe to learn about the QCD dynamics at finite density. First, we discuss the properties of the $J/\psi$ and $D$ meson at finite nucleon density. We discuss why their properties should change at…
In QCD at high density, the color-octet quark-antiquark condensate $\langle\overline\psi\gamma_0(\lambda^A)_C (\lambda^A)_F\psi\rangle$ is generally nonzero and dynamically breaks the $\mathrm{SU}(3)_C\times…
The rise of the total, elastic and inelastic hadronic cross sections at high energies is investigated by means of an analytical parametrization, with the exponent of the leading logarithm contribution as a free fit parameter. Using…
We investigate the in-medium modification of pseudoscalar and vector mesons in a QCD motivated chiral quark model by solving the Dyson-Schwinger equations for quarks and mesons at finite temperature for a wide mass range of meson masses,…
We consider the singular behaviour of QCD scattering amplitudes in kinematical configurations where two or more momenta of the external partons become collinear. At the tree level, this behaviour is known to be controlled by factorization…
The order parameter of the chiral phase transition is directly related to the infrared part of the spectrum of the QCD Dirac operator. This part of the spectrum follows from the low energy limit of QCD which is given by a partition function…