No Arabic abstract
Exact analytical forms of solutions for Dispersion Relations for Amplitudes and Dispersion Relations for Slopes are applied in the analysis of pp and $rm {p bar p}$ scattering data in the forward range at energies below $sqrt(s)approx 30 GeV$. As inputs for the energy dependence of the imaginary part, use is made of analytic form for the total cross sections and for parameters of the $t$ dependence of the imaginary parts, with exponential and linear factors. A structure for the $t$ dependence of the real amplitude is written, with slopes $B_R$ and a linear factor $rho-mu_R t$ that allows compatibility of the data with the predictions from dispersion relations for the derivatives of the real amplitude at the origin. A very precise description is made of all $dsigma/dt$ data, with regular energy dependence of all quantities. It is shown that a revision of previous calculations of total cross sections, slopes and $rho$ parameters in the literatures is necessary, and stressed that only determinations based on $dsigma/dt$ data covering sufficient $t$ range using appropriate forms of amplitudes can be considered as valid.
The production of heavy flavour hadrons in $pp$ collisions at large values of their transverse momenta can be a new unique source for estimation of intrinsic heavy quark contribution to the proton. We analyze the inclusive production of the open strangeness and the semi-inclusive hard processes of the photon and vector boson production accompanied by the $c$- or $b$-jets in $pp$ collisions. We show that one should select the parton-level (sub)processes (and final-state signatures) that are the most sensitive to the intrinsic heavy quark contributions. We present some predictions for these processes made within the perturbative QCD including the intrinsic strangeness and intrinsic charm in the proton that can be verified in the NA61 experiment and at LHC.
Up to now, the existence of intrinsic (or valence-like) heavy quark components of the proton distribution function has not yet been confirmed or rejected. We show that this hypothesis can be verified at experiments on the inclusive production of the open strangeness (NA61) and at measurements of prompt photons or vector bosons accompanied by heavy flavour jets performed at LHC, CERN. Our theoretical study demonstrates that investigations of the intrinsic heavy quark contributions look very promising in hard processes like $pprightarrow K^pm+X$ and $pprightarrowgamma/Z/W +c(b)+X$. A possible observation of these components at the CBM, NICA experiments is discussed also.
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.
In the analysis of experimental data on $p p$ (or $bar p p$) elastic differential cross section it is customary to define an average forward slope $b$ in the form $exp{(-b|t|)}$, where $t$ is the momentum transfer. Taking as working example the results of experiments at Tevatron and SPS, we will show with the help of the impact picture approach, that this simplifying assumption hides interesting information on the complex non-flip scattering amplitude, and that the slope $b$ is not a constant. We investigate the variation of this slope parameter, including a model-independent way to extract this information from an accurate measurement of the elastic differential cross section. An extension of our results to the LHC energy domain is presented in view of future experiments.
We study multiplicity correlations of hadrons in forward and backward hemispheres in $pp$ inelastic interactions at energies 200GeV $leq sqrt{s} leq$ 13TeV within the microscopic quark-gluon string model. The model correctly describes (i) the almost linear dependence of average multiplicity in one hemisphere on the particle multiplicity in other hemisphere in the center-of-mass frame; (ii) the increase of the slope parameter $b_{corr}$ with rising collision energy; (iii) the quick falloff of the correlation strength with increase of the midrapidity gap; (iv) saturation of the forward-backward correlations at very high multiplicities. Investigation of the sub-processes on partonic level reveals that these features can be attributed to short-range partonic correlations within a single string and superposition of several sub-processes containing different numbers of soft and hard Pomerons with different mean multiplicities. If the number of Pomerons in the event is fixed, no forward-backward correlations are observed. Predictions are made for the top LHC energy $sqrt{s} = 13$TeV.