Radiative Corrections to QCD Amplitudes in Quasi-Multi-Regge Kinematics

Radiative corrections to QCD amplitudes in the quasi-multi-Regge kinematics are interesting in particular since the Reggeized form of these amplitudes is used in the derivation of the NLO BFKL. This form is a hypothesis which must be at least carefully checked, if not proved. We calculate the radiative corrections in the one-loop approximation using the s-channel unitarity. Compatibility of the Reggeized form of the amplitudes with the s-channel unitarity requires fulfillment of the set of nonlinear equations for the Reggeon vertices. We show that these equations are satisfied.Comment: 28 pages,3 figure

Explicit Free Parameterization of the Modified Tetrahedron Equation

The Modified Tetrahedron Equation (MTE) with affine Weyl quantum variables at N-th root of unity is solved by a rational mapping operator which is obtained from the solution of a linear problem. We show that the solutions can be parameterized in terms of eight free parameters and sixteen discrete phase choices, thus providing a broad starting point for the construction of 3-dimensional integrable lattice models. The Fermat curve points parameterizing the representation of the mapping operator in terms of cyclic functions are expressed in terms of the independent parameters. An explicit formula for the density factor of the MTE is derived. For the example N=2 we write the MTE in full detail. We also discuss a solution of the MTE in terms of bosonic continuum functions.Comment: 28 pages, 3 figure

Role of quark-instanton liquid interactions in colour superconductivity phase

The interaction of light quarks and instanton liquid is analyzed at finite density of quark/baryon matter and in the phase of nonzero values of diquark (colour) condensate. It is shown that instanton liquid perturbation produced by such an interaction results in an essential increase of the critical value of quark chemical potential $\mu_c$ which provokes the perceptible increase of quark matter density around the expected onset of the colour superconductivity phase.Comment: 11 pages, 5 figure

New Evidence for Supernarrow Dibaryons Production in pd Interactions

The analysis of new experimental data, obtained at the Proton Linear Accelerator of INR, with the aim to search for supernarrow dibaryons in the $pd\to ppX_1$ and $pd\to pdX_2$ reactions is presented. Narrow peaks with an experimental width of 5 MeV at masses of 1904$\pm 2$, 1926$\pm 2$, and 1942$\pm 2$ MeV have been observed in missing mass $M_{pX_1}$ spectra. In the missing mass $M_{X_1}$ spectra, the peaks at $M_{X_1}=966\pm 2$, 986$\pm 2$, and 1003$\pm 2$ MeV have been found. The analysis of the data obtained leads to the conclusion that the observed peaks in $M_{pX_1}$ spectra are most likely supernarrow dibaryons, the decay of which into two nucleons is forbidden by the Pauli exclusion principle. An alternative interpretation of the spectra by assuming a decay of the supernarrow dibaryons in "exotic baryon states" with masses $M_{X_1}$ is discussed.Comment: 17 pages, 6 figures. Considerably expanded version accepted for publication in Eur. Phys. J. A; a discussion, 4 figures and several references have been added, the title has been change

Quasiparticle electronic band structure of the alkali metal chalcogenides

The electronic energy band spectra of the alkali metal chalcogenides M$_2$A (M: Li, Na, K, Rb; A: O, S, Se, Te) have been evaluated within the projector augmented waves (PAW) approach by means of the ABINIT code. The Kohn-Sham single-particle states have been found in the GGA (the generalized gradient approximation) framework. Further, on the basis of these results the quasiparticle energies of electrons as well as the dielectric constants were obtained in the GW approximation. The calculations based on the Green's function have been originally done for all the considered M$_2$A crystals, except Li$_2$O.Comment: 8 pages, 8 figure