ar X iv : h ep - p h / 05 05 05 8 v 2 7 J ul 2 00 5 Predictions of pp , p̄p total cross section and ρ ratio at LHC and cosmic - ray energies

We propose to use rich informations on the pp, p̄p total cross sections σtot below N(∼ 10)GeV in order to predict the total cross section and ρ ratio at very high energies. Using the FESR as a constraint for high energy parameters, we search for the simultaneous best fit to the data points of σtot and ρ ratio up to some energy (e.g., ISR, Tevatron) to determine the high-energy parameters. We then predict σtot and ρ in the LHC and high-energy cosmic-ray regions. Using the data up to √ s = 1.8TeV(Tevatron), we predict σ tot and ρ pp at the LHC energy( √ s = 14TeV) as 106.3 ± 5.1syst ± 2.4statmb and 0.126 ± 0.007syst ± 0.004stat , respectively. The predicted values of σtot in terms of the same parameters are in good agreement with the cosmic-ray experimental data sample up to Plab ∼ 108∼9GeV by Block, Halzen, and Stanov.