Ratios of Antiparticle/Particle Yields in Hadron-Hadron and Heavy Ion Collisions
We compare the numerical results for antibaryon/baryon production ratios in high energy heavy ion collisions with some theoretical models.
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arXiv subjects
Yu. M. Shabelski
Publications and source records attributed to Yu. M. Shabelski.
Inclusive density of secondaries in heavy ion collisions
The inclusive density of charged secondaries produced in high energy heavy ion collisions are calculated in the framework of multiple scattering theory and quark-gluon string model. The obtained results are in agreement with the data only assuming rather large inelastic screening/percolation effects. We predict the total saturation of relative inclusive densities in dependence on the number of interacting nucleon. Predictions for LHC are also given.
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Cross Sections, Probabilities, Multiplicities and Spectra of Secondaries in High Energy Heavy Ion Interactions
We present a short review of theoretical results (mainly for experimentalists) published in many different papers. The formulae are presented for the different integrated cross sections, the number of interacting nucleons, multiplicities of secondaries, the dispersions of multiplicity distributions. Two possible tests for the search of Quark-Gluon Plasma formation are discussed. CERN SPS data for production of secondaries in central Pb+Pb collisions are compared with Quark-Gluon String Model predictions.
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Heavy quark hadroproduction in k_T-factorization approach and the experimental data
We compare the numerical predictions of the k_T-factorization approach (semihard theory) for heavy quark production in high energy nucleon-nucleon and photon-nucleon collisions with the experimental data from Tevatron-collider and HERA. Predictions for heavy quark production at Tevatron, LHC and HERA are also presented.
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Baryon Number Transfer in Hadronic Interaction
The process of baryon number transfer due to string junction propagation in rapidity is considered. It has a significant effect in the net baryon production in $pp$ collisions at mid-rapidities and an even larger effect in the forward hemisphere in the cases of $πp$ and $γp$ interactions. The results of numerical calculations in the framework of the Quark-Gluon String model are in reasonable agreement with the data.
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Heavy Quark Production in Hadron Collisions
We compare the numerical predictions for heavy quark production in high energy hadron collisions in the conventional QCD parton model and the k_T-factorization approach (semihard theory). The total production cross sections, one-particle rapidity and p_T distributions as well as several two-particle correlations are considered. Some of them can help to estimate QCD scale. The differense in the predictions of the two approaches is not very large, while the shapes of the distributions are sometimes different.
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The Role of Hadronization in Charm and Beauty Production
We discuss the relative role of fragmentation and recombination processes for heavy flavour hadron production in different kinematical regions in high energy hadron-hadron and photon-hadron collisions. We predict several qualitative features which should be observed if our picture of heavy flavour production is consistent.
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Comparison of $k_T$-Factorization Approach and QCD Parton Model for Charm and Beauty Hadroproduction
We compare the numerical predictions for heavy quark production in high energy hadron collisions of the conventional QCD parton model and the $k_T$-factorization approach (semihard theory). The total production cross sections, one-particle rapidity and $p_T$ distributions as well as two-particle correlations are considered. The difference in the predictions of the two approaches is not very large, while the shapes of the distributions are slightly different.
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Charm Hadroproduction in $k_T$-Factorization Approach
We compare the theoretical status and the numerical predictions of two approaches for heavy quark production in the high energy hadron collisions, namely the conventional LO parton model with collinear approximation and $k_T$-factorization approach. The main assumptions used in the calculations are discussed. To extract the differences coming from the matrix elements we use very simple gluon structure function and fixed coupling. It is shown that the $k_T$-factorization approach calculated formally in LO and with Sudakov form factor accounts for many contributions related usually to NLO (and even NNLO) processes of the conventional parton model
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Quark Model and Neutral Strange Secondary Production by Neutrino and Antineutrino Beams
The experimental data on $K^0$ and $Λ$ production by $ν$ and $\barν$ beams are compared with the predictions of quark model assuming that the direct production of secondaries dominates. Disagreement of these predictions with the data allows one to suppose that there exists considerable resonance decay contribution to the multiplicities of produced secondaries.
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The Role of Incident Parton Transverse Momenta in Heavy Quark Hadroproduction
The conventional NLO parton model is enough for the description of total cross sections and one-particle distributions. In the case of two-particle correlations, the collinear approximation has failed, and it is necessary to account for the transverse momenta of initial partons. The different possibilities to do this are discussed.
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Impact Parameter Dependences of the Number of Interacting Nucleons and Mean Multiplicities in High Energy Heavy Ion Interactions
We consider the dependences of the average number of interacting nucleons in high energy heavy ion collisions on the impact parameter in two cases, when the colliding nuclei have equal atomic weights, and when one nucleus is significantly more heavy in comparison with the second one. We argue that in the case of trigger of some rare event (say, $J/ψ$, or $Υ$ production) the multiplicity of the secondaries can change several times for minimum bias sample, but it should be stable in the case of central events.
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t-dependences of vector meson diffractive production in ep collisions
We calculate $p_T$-dependences of diffractive vector meson photo- and electroproduction in electron-proton collisions with and without proton dissociation at small momenta transfers. The calculated slopes are in good agreement with the data.
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Stripping Cross Sections in Collisions of Light Nuclei
By evaluating all the contributions of the intermediate states of the multiple scattering theory diagrams, we compute the integrated stripping cross sections of collisions among light nuclei. The resulting expressions have the simple form of a combination of total inelastic cross sections of nuclear reactions with projectile nuclei differing in the atomic mass number. We also check the accuracy of some widely used relations in heavy ion collisions.
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Elastic ρ' and ϕMeson Photo- and Electroproduction with Non-Resonant Background
The backgrounds due to the direct diffractive dissociation of the photon into the $π^+π^-$ as well as $K^+K^-$ pairs to the "elastic" diffractive $ρ'$ and $ϕ$ mesons production in electron-proton collisions are calculated. It is shown that the role of background and background-resonant interference contributions is very important in experimental distribution of $M_{π^+ π^-}$ in the $ρ'$ mass region. The amplitude for the background process is proportional to the $π$-meson - proton or K-meson - proton cross sections. Therefore, describing the HERA data, one can estimate $σ(πp)$ and $σ(Kp)$ at energies higher than the region of direct measurements.
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How to account for the interference contributions in monte carlo simulations
The diagram technique allows one to calculate the correction factors which can be used in Monte Carlo simulation of some processes. This is equivalent to the calculation with accounting for all or some part of the interference contributions. The example is presented for the simplest case of inelastic deuteron-deuteron interactions.
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Heavy quark pair correlations in QCD
The azimutal correlations of heavy quarks produced in the high energy $pp$ ($p\bar{p}$) collisions are calculated in the framework of QCD without the usual assumptions of the parton model. The virtual nature of the interacting gluons as well as their transverse motion and different polarizations are taken into account. We give some predictions for the azimutal correlations of charm and beauty hadrons produced at Tevatron-collider and LHC.
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Nuclear Effects in Charmonium Production in QCD
It is shown that the nuclear shadowing of charmonium due to the modification of the nuclear parton distribution is similar in the factorization approach based on non relativistic QCD and in the color evaporation model. In the first model, a separate study of the color octet and color singlet contributions to the yields of the various charmonium states as well as the contributions of these states to the total $J/Ψ$ production is performed. It is found a clear $x_F$ dependence of these contributions which can reproduce experimental data for moderate $x_F$.
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