Integral and derivative dispersion relations in the analysis of the data on pppp and pˉp\bar pp forward scattering

Integral and derivative dispersion relations (DR) are considered for the $pp$ and $\bar pp$ forward scattering amplitudes. A new representation for the derivative DR, valid at lower energies than the standard one, is obtained. The data on the total cross sections of $pp (\bar pp)$ interaction as well as those on the ratio of the real part to the imaginary part of the forward amplitude are analyzed within various forms of the DR and high-energy Regge models. It is shown that three models for the pomeron, simple pole with intercept larger than one, triple pole pomeron and double pole pomeron (both with intercept equal to one) lead to practically equivalent descriptions of the data at $\sqrt{s}>5$ GeV. It is also shown that the low-energy part of the dispersion integral (from the two-proton threshold up to $\sqrt{s}=5$ GeV) allows one to reproduce well the data on $\rho$ at lower energies without additional free parametersComment: 9 pages (LaTeX) including 4 figures. To be published in Proceedings of the International Conference "New trends in high-energy physics" in Alushta, Ukraine, May 24-31, 200

Integral and derivative dispersion relations, analysis of the forward scattering data

Integral and derivative dispersion relations (DR) are considered for the forward scattering $pp$ and $\bar pp$ amplitudes. A new representation for the derivative DR, valid not only at high energy, is obtained. The data on the total cross sections for $pp (\bar pp)$ interaction as well as the data on the parameter $\rho$ are analyzed within the various forms of the DR and high-energy Regge models. It is shown that three models for the Pomeron, Simple pole Pomeron, Tripole Pomeron and Dipole Pomeron (the both with the intercept equal unit) lead to practically equivalent description of the data at $\sqrt{s}>$5 GeV. It is also shown that the correctly calculated low-energy part of the dispersion integral (from the two-proton threshold up to $\sqrt{s}=$5 GeV) allows to reproduce well the $\rho$ data at low energies without additional free parameters.Comment: LaTeX, 3 pages, 2 eps figures, talk presented by E. Martynov at the International Europhysics Conference on High Energy Physics (HEP 2003), 17-23 July 2003, Aachen, German

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

The soft and the hard pomerons: elastic scattering and unitarisation

The hard pomeron component needed to reproduce small-x data seems to be present in elastic scattering at moderate energy. If this is the case, it is likely that the total cross section at the LHC will be appreciably larger than previously expected.Comment: Talk given at 12th International Conference on Elastic and Diffractive Scattering: Forward Physics and QCD, Hamburg, DESY, Germany, 21-25 May 200