Chiral color symmetry and possible G′G'-boson effects at the Tevatron and LHC

A gauge model with chiral color symmetry is considered and possible effects of the color $G'$-boson octet predicted by this symmetry are investigated in dependence on two free parameters, the mixing angle $\theta_G$ and $G'$ mass $m_{G'}$. The allowed region in the $m_{G'} - \theta_G$ plane is found from the Tevatron data on the cross section $\sigma_{t\bar{t}}$ and forward-backward asymmetry $A_{\rm FB}^{p \bar p}$ of the $t\bar{t}$ production. The mass limits for the $G'$-boson are shown to be stronger than those for the axigluon. A possible effect of the $G'$-boson on the $t\bar{t}$ production at the LHC is discussed and the mass limits providing for the $G'$-boson evidence at the LHC are estimated in dependence on $\theta_G$.Comment: 11 pages, 2 figures, accepted for publication in Modern Physics Letters

Impact analysis of TOTEM data at the LHC: black disk limit exceeded

We discuss the profile of the impact--parameter dependent elastic scattering amplitude. Extraction of impact-parameter dependence from the dataset with inclusion of the experimental data on elastic scattering at the LHC energies helps to reveal the asymptotics of hadron interactions. Analysis of the data clearly indicates that the impact-parameter elastic scattering amplitude exceed the black disk limit at the LHC energy 7TeV and the inelastic overlap function reaches its maximum value at $b>0$Comment: 5 pages, 5 figure

Non-existence of normal tokamak equilibria with negative central current

Recent tokamak experiments employing off-axis, non-inductive current drive have found that a large central current hole can be produced. The current density is measured to be approximately zero in this region, though in principle there was sufficient current drive power for the central current density to have gone significantly negative. Recent papers have used a large aspect-ratio expansion to show that normal MHD equilibria (with axisymmetric nested flux surfaces, non-singular fields, and monotonic peaked pressure profiles) can not exist with negative central current. We extend that proof here to arbitrary aspect ratio, using a variant of the virial theorem to derive a relatively simple integral constraint on the equilibrium. However, this constraint does not, by itself, exclude equilibria with non-nested flux surfaces, or equilibria with singular fields and/or hollow pressure profiles that may be spontaneously generated.Comment: 5 pages, 3 figures. Submitted to Physics of Plasmas, Feb. 14, 2003. Revised Feb. 24, 2003. Vers. 2: revised May 29 to clarify points raised by referee, add references to recent work. July 18, accepted for publicatio

Nonlinearities and Pomeron Nonfactorizability in Conventional Diffraction

Alternatives for describing the nonlinear behavior of the first diffraction cone in differential $pp$ and $\bar pp$ elastic cross-section are investigated. High quality fits to the data are presented. We show that the presence in the Pomeron amplitude of two terms with different $t$ dependences is strongly suggested by the data, hinting at a non-factorizable Pomeron even in the field of purely hadronic reactions. The available data, however, do no allow to choose among a nonlinearity in the residues or in the Pomeron trajectory or in both. In all cases, we find an effective slope of the trajectory larger than the one currently used. A nonlinear trajectory with the fitted parameters is used for predicting the mass and the width of the 2$^{++}$ glueball. An excellent agreement is found with the X(1900) candidate from the WA91 experiment.Comment: Plain TeX, 24 pages, 6 eps figures, to be published in Nuovo Ciment

Unified Model for Small-t and High-t Scattering at High Energies: Predictions at RHIC and LHC

The urgency of predictions in large-t region at LHC stimulated us to present a unified model of small and high t scattering at high energies. Our model is based upon a safe theoretical ground: analyticity, unitarity, Regge behavior, gluon exchange and saturation of bounds established in axiomatic quantum field theory. We make precise predictions for the behavior of the differential cross sections at high t, the evolution of the dip-shoulder structure localized in the region of -t between 0.5 and 0.8 GeV**2 and the radical violation of the exponential behavior of the first diffraction cone at small t.Comment: 6 pages, 2 table, 7 figures. Misprints are correcte

Temperature doubling of resonance frequency in Dicke model

It is found that doubling of a resonance frequency in the Dicke model increases with decreasing temperature. If the atom density is greater than the threshold density one of the resonance frequencies tends to zero when the temperature decreases from high temperatures to the phase transition point (soft mode). © 1976

Associative production of B_c and D mesons at LHC

It is shown that the study of correlations in the associative production of B_c and D mesons at LHC allows to obtain the essential information about the B_c production mechanism.Comment: 14 pages, 10 figures. Some misprints have been removed in the last version. The reference to CTEQ pdf has been adde