Elastic Amplitudes and Observables in pp Scattering

Using a unified analytic representation for the elastic scattering amplitudes of pp scattering valid for all high energy region, the behavior of observables in the LHC collisions in the range $\sqrt{s}$ = 2.76 - 14 TeV is discussed. Similarly to the case of 7 TeV data, the proposed amplitudes give excellent description of the preliminary 8 TeV data. We discuss the expected energy dependence of the observable quantities, and present predictions for the experiments at 2.76, 13 and 14 TeV.Comment: 4 pages, 4 figures Contribution to Proceedings of DIFFRACTION 201

pp Elastic Scattering at LHC Energies

Using a unified analytic representation for the elastic scattering amplitudes of pp scattering valid for all energy region, the behavior of observables in the LHC collisions in the range $\sqrt{s}$= 2.76 - 14 TeV is discussed. Similarly to the case of 7 TeV data, the proposed amplitudes give excellent description of the preliminary 8 TeV data. We discuss the expected energy dependence of the observable quantities, and present predictions for the experiments at 2.76, 13 and 14 TeV.Comment: 16 pages, 17 figure

Energy dependence of proton-proton elastic scattering at large momentum transfer

The measurements of proton-proton elastic scattering for large momentum transfer at energies in the range $\approx$ 20 to 60 GeV show a simple behaviour of form $d \sigma/dt \approx {\rm const}~|t|^{-8}$, apparently with no energy dependence. In the present work detailed analysis of the data shows a decrease of the magnitude of the tail with the energy, still with preservation of the power $|t|^{-8}$. The analysis allows the definition of a band for the energy dependence with the form of a power of the strong coupling $\alpha_S^{1.57}$. The rate of decrease describes very well the data at the distant energy $\sqrt{s}$ = 13 TeV, with reduction of the cross section by a factor 5.71. This result gives prediction for new experiments at high energies, and opens important question for theoretical investigation.Comment: 6 pages, 5 figures and 1 tabl

Observation of two zeros of the real amplitude in pp scattering at LHC energies

Elastic scattering of charged hadrons is described by the combination of nuclear and Coulomb amplitudes. It is well know that at the very forward range the nuclear real and Coulomb parts interplay a crucial role in the determination of the magnitude of the real part at $$|t|=0$$. However, beyond $$|t|=0$$ the real and imaginary nuclear amplitudes have different t dependencies and we show that at LHC energies the zeros formed by the combination $$T_C(t)+T_R^N(s,t)=0$$ in pp process can be potentially observed when the background due to the imaginary part is removed. This observation constrains the real part at this forward range

Low projectile density contributions in the dilute-dense CGC framework for two-particle correlations

International audienceAt leading-order, the standard dilute-dense Color Glass Condensate formula used for two-particle correlations in proton-nucleus collisions, whose symmetries prevent the generation of odd azimuthal anisotropy harmonics, is the dilute projectile limit of the dense-dense formalism. However, when the projectile is genuinely dilute, the complete formulation contains additional contributions at the same leading order in the strong coupling constant. In this work we investigate those low projectile density contributions that are relevant when the particles are produced at forward rapidities. We find that they are responsible for non-zero odd harmonics which are negative, in qualitative agreement with recent experimental measurements at the Relativistic Heavy-Ion Collider

Signature of Accidental Symmetry Breaking in Two-particle Correlations within the CGC

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Evolution equation for elastic scattering of hadrons

We turn high energy elastic scattering of hadrons into an initial value problem using an evolution equation based on the Regge Field Theory, which has a form of the complex nonlinear reaction–diffusion equation, with time being played by the logarithm of energy. The initial conditions are provided by the data-driven models for the real and imaginary parts of the amplitude. Numerical calculations of pp differential cross sections and forward quantities for LHC energies agree very well with experimental data extending up to, and including the diffractive cone. Furthermore, we show that at current accessible energies the non-linear effects play an important role, as the impact parameter space profiles approach the unitarity bound. The equation also predicts some other effects discussed in the literature, like the hollowness of nuclear matter or existence of stationary points in momentum transfer t