Multiparticle production and perturbative QCD

The perturbative quantum chromodynamics (QCD) is quite successful in the description of main features of multiparticle production processes. Ten most appealing characteristics are described in this brief review talk and compared with QCD predictions. The general perturbative QCD approach is demonstrated and its problems are discussed. It is shown that the analytical calculations at the parton level with the low-momentum cut-off reproduce experimental data on the hadronic final state surprisingly accurately even though the perturbative expansion parameter is not very small. Moreover, the perturbative QCD has been able not only to {\it describe} the existing data but also to {\it predict} many new bright qualitative phenomena.Comment: 22 pages, 10 Figs, LATEX. Talk given at the conference "From the smallest to largest distances", ITEP, Moscow, 24-26 May 200

Network modeling of biological treatment complex of polymer production waste water

© 2015, Asian Social Science. All rights reserved. The article discusses technological complex of biochemical wastewater treatment (BWWT) of polymer production. Based on the review of the main methods of modeling discrete-continuous biochemist technology systems (BCTS) it substantiates the appropriateness of applying the of Petri nets (PN) theory for modeling BWWT of polymer industries. It is proposed to use a modification of Petri nets that focuses on modeling and analysis of discrete-continuous BCTS, by introducing priority transitions, deterministic time delays for transitions and places. A model in the form of a modified Petri net (MPN) is constructed. By means of SCADA TRACE MODE, software package to control BWWT technology system is designed

Network Modelling of Functioning System of the Process Module of Oil-Contaminated Wastewater Treatment

Abstract The article discusses network modeling of oil-contaminated waste water treatment at the stage of the process module functioning of water jet cleaning of waste water in the oil fields and petrochemical industries. Based on the review of the main modeling methods of discrete-continuous chemical processes, expediency of using the theory of Petri nets (PN) for modeling the process of wastewater treatment in the oil fields and petrochemical industries is substantiated. It is proposed to use a modification of Petri nets which is focused on modeling and analysis of discrete-continuous chemical processes by prioritizing transitions, timing marks in positions and transitions. A model in the form of modified Petri nets (MPN) is designed. A software package to control the process for wastewater treatment is designed by means of SCADA TRACE MODE

Ensuring environmental safety based on the modeling of biological process of oily sewage

© MCSER-Mediterranean Center of Social and Educational Research. The article discloses the main areas of institutional support for sustainable ecological and economic development of economic entities on the basis of conceptual approaches to the systematization of methods and mechanisms for the protection of their economic interests. There described the mathematical basis of Petri nets used in the modeling and design of the module bioremediation of hydrocarbon wastewater. There described the technique of two-tier system of the modeling process of biochemical treatment of oily wastewater, as well as a model developed by the authors in the form of a modified Petri nets and software package management system of biochemical treatment of wastewater

Evolution of average multiplicities of quark and gluon jets

The energy evolution of average multiplicities of quark and gluon jets is studied in perturbative QCD. Higher order (3NLO) terms in the perturbative expansion of equations for the generating functions are found. First and second derivatives of average multiplicities are calculated. The mean multiplicity of gluon jets is larger than that of quark jets and evolves more rapidly with energy. It is shown which quantities are most sensitive to higher order perturbative and nonperturbative corrections. We define the energy regions where the corrections to different quantities are important. The latest experimental data are discussed.Comment: 23 pages including 3 figures. Version 2 contains small correction to equation (41

Corrections to Angular Ordering in Multiple Hadroprodroproduction

One of the key ideas in describing the multiparticle production at high energies in the perturbative QCD is the angular ordering in successive soft-gluon emission. We analyse the angular distribution of particles in a jet, and investigate the corrections to the angular ordering. At a small angle from the jet direction, the angular ordering is exact at the next-to-leading order. At a large angle, the angular ordering overestimates the angular particle density by a factor $(1-\gamma\ln \cos^2(\theta/2))$, where $\gamma$ is the anomalous dimension of the multiplicity. The $O(\gamma)$ correction restores the boost invariance of the cross section.Comment: Latex fil

A possible explanation why the Theta+ is seen in some experiments and not in others

To understand the whole set of positive and null data on the Theta+(1530)-production, we suggest the hypothesis that multiquark hadrons are mainly generated from many-quark states, which emerge either as short-term hadron fluctuations, or as hadron remnants in hard processes. This approach allows us to describe both non-observation of the Theta+ in current null experiments and peculiar features of its production in positive experiments. Further, we are able to propose new experiments that might be decisive for the problem of the Theta+ existence. Distributions of the Theta+ in such experiments can give important information both on higher Fock components of conventional hadrons and about structure and hadronization properties of hadron remnants produced in hard processes. We also explain that description of multiquark hadrons may require a modified form of the constituent quark model, with quark masses and couplings being intermediate between their values for the familiar constituent quarks and the current ones.Comment: 18 pages. Some changes in the text; experimental suggestions collected in a special subsection, references added and refreshe

Charged current cross section for massive cosmological neutrinos impinging on radioactive nuclei

We discuss the cross section formula both for massless and massive neutrinos on stable and radioactive nuclei. The latter could be of interest for the detection of cosmological neutrinos whose observation is one of the main challenges of modern cosmology. We analyze the signal to background ratio as a function of the ratio of the neutrino mass over the detector resolution and show that an energy resolution less than 0.5 eV would be required for sub-eV neutrino masses, independently of the gravitational neutrino clustering. Finally we mention the non-resonant character of neutrino capture on radioactive nuclei.Comment: 5 pages, 2 figure

Rapidity gaps in perturbative QCD

We analyze diffractive deep inelastic scattering within perturbative QCD by studying lepton scattering on a heavy quark target. Simple explicit expressions are derived in impact parameter space for the photon wave function and the scattering cross sections corresponding to single and double Coulomb gluon exchange. At limited momentum transfers to the target, the results agree with the general features of the ``aligned jet model''. The color--singlet exchange cross section receives a leading twist contribution only from the aligned jet region, where the transverse size of the photon wave function remains finite in the Bjorken scaling limit. In contrast to inclusive DIS, in diffractive events there is no leading twist contribution to $\sigma_L/\sigma_T$ from the lowest order $(q\bar q)$ photon Fock state, and the cross section for heavy quarks is power suppressed in the quark mass. There are also important contributions with large momentum transfer to the target, which corresponds to events having high transverse momentum production in both the projectile and target rapidity regions, separated by a rapidity gap.Comment: 27 pages, LaTeX, 6 figures. Duplicate figure removed, paper unchange