A new method for the determination of the real part of the hadron elastic scattering amplitude at small angles and high energies

Abstract A new method for the determination of the real part of the elastic scattering amplitude is examined for high energy proton–proton at small momentum transfer. This method allows us to decrease the number of model assumptions, to obtain the real part in a narrow region of momentum transfer and to test different models. The real part is computed at a given point t min near t = 0 from the known Coulomb amplitude. Hence one obtains an important constraint on the real part of the forward scattering amplitude and therefore on the ρ -parameter (measuring the ratio of the real to imaginary part of the scattering amplitude at t = 0 ), which can be tested at LHC.