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Dubna, Russia

Zhabitsky V.M.,JINR
RuPAC 2012 Contributions to the Proceedings - 23rd Russian Particle Accelerator Conference | Year: 2012

The transient beam response to an externally applied impulse force in synchrotrons with a digital transverse feedback system is studied. Experimental data from the LHC on damping of coherent transverse oscillations excited by the discrete-time unit impulse are analysed. Good agreement on the measured and theoretically predicted decrements has been obtained. A method of feedback fine tuning, based on measurements of the bunch response to the harmonic excitation impulse, is discussed. Copyright © 2012 by the respective authors. Source

Kokoulina E.S.,JINR
Physics of Particles and Nuclei Letters | Year: 2016

Study of high multiplicity events in proton-proton interactions is carried out at the U-70 accelerator (IHEP, Protvino). These events are extremely rare. Usually, Monte Carlo codes underestimate topological cross sections in this region. The gluon dominance model (GDM) was offered to describe them. It is based on QCD and a phenomenological scheme of a hadronization stage. This model indicates a recombination mechanism of hadronization and a gluon fission. Future program of the SVD Collaboration is aimed at studying a long-standing puzzle of excess soft photon yield and its connection with high multiplicity at the U-70 and Nuclotron facility at JINR, Dubna. © 2016, Pleiades Publishing, Ltd. Source

Kokoulina E.,JINR
Progress of Theoretical Physics Supplement | Year: 2012

Neutral pion fluctuations have been measured in proton interactions at U-70 accelerator (IHEP, Protvino). The experiment is carried out with the SVD-2 setup. Charged and neutral particles were registered simultaneously. The reconstruction of π ο-mesons is fulfilled using gamma quanta registered with the electromagnetic calorimeter. The corrections on the detectors acceptance, triggering, efficiencies and the reconstruction algorithm were applied. The multiplicity distributions of the neutral pions were analysed to define the scaled variance, ω, for π ο-mesons. The revealed sharp growth of fluctuations of the neutral pion number at total meson multiplicities more than 22 can indicate the Bose-Einstein condensate formation. Source

Zlokazov V.B.,JINR
Computer Physics Communications | Year: 2013

The program VACTIV-Visual ACTIV-has been developed for an automatic analysis of spectrum-like distributions, in particular gamma-ray spectra or alpha-spectra and is a standard graphical dialog based Windows XX application, driven by a menu, mouse and keyboard. On the one hand, it was a conversion of an existing Fortran program ACTIV [1] to the DELPHI language; on the other hand, it is a transformation of the sequential syntax of Fortran programming to a new object-oriented style, based on the organization of event interactions. New features implemented in the algorithms of both the versions consisted in the following • as peak model both an analytical function and a graphical curve could be used; • the peak search algorithm was able to recognize not only Gauss peaks but also peaks with an irregular form; both narrow peaks (2-4 channels) and broad ones (50-100 channels); • the regularization technique in the fitting guaranteed a stable solution in the most complicated cases of strongly overlapping or weak peaks. The graphical dialog interface of VACTIV is much more convenient than the batch mode of ACTIV. [1] V.B. Zlokazov, Computer Physics Communications, 28 (1982) 27-37. NEW VERSION PROGRAM SUMMARY: Program Title: VACTIV. Catalogue identifier: ABAC_v2_0. Licensing provisions: no. Programming language: DELPHI 5-7 Pascal. Computer: IBM PC series. Operating system: Windows XX. RAM: 1 MB. Keywords: Nuclear physics, spectrum decomposition, least squares analysis, graphical dialog, object-oriented programming. Classification: 17.6. Catalogue identifier of previous version: ABAC_v1_0. Journal reference of previous version: Comput. Phys. Commun. 28 (1982) 27. Does the new version supersede the previous version?: Yes. Nature of problem: Program VACTIV is intended for precise analysis of arbitrary spectrum-like distributions, e.g. gamma-ray and X-ray spectra and allows the user to carry out the full cycle of automatic processing of such spectra, i.e. calibration, automatic peak search and estimation of parameters of interest. VACTIV can run on any standard modern laptop. Reasons for the new version: At the time of its creation (1999) VACTIV was seemingly the first attempt to apply the newest programming languages and styles to systems of spectrum analysis. Its goal was to both get a convenient and efficient technique for data processing, and to elaborate the formalism of spectrum analysis in terms of classes, their properties, their methods and events of an object-oriented programming language. Summary of revisions: Compared with ACTIV, VACTIV preserves all the mathematical algorithms, but provides the user with all the benefits of an interface, based on a graphical dialog. It allows him to make a quick intervention in the work of the program; in particular, to carry out the on-line control of the fitting process: depending on the intermediate results and using the visual form of data representation, to change the conditions for the fitting and so achieve the optimum performance, selecting the optimum strategy. To find the best conditions for the fitting one can compress the spectrum, delete the blunders from it, smooth it using a high-frequency spline filter and build the background using a low-frequency spline filter; use not only automatic methods for the blunder deletion, the peak search, the peak model forming and the calibration, but also use manual mouse clicking on the spectrum graph. Restrictions: To enhance the reliability and portability of the program the majority of the most important arrays have a static allocation; all the arrays are allocated with a surplus, and the total pool of the program is restricted only by the size of the computer virtual memory. A spectrum has the static size of 32 K real words. The maximum size of the least-square matrix is 314 (the maximum number of fitted parameters per one analyzed spectrum interval, not for the whole spectrum), from which it follows that the maximum number of peaks in one spectrum interval is 154. The maximum total number of peaks in the spectrum is not restricted. Running time: The calculation time is negligibly small compared with the time for the dialog; using ini-files the program can be partly used in a semi-dialog mode. © 2013. Source

Musulmanbekov G.,JINR
Journal of Physics: Conference Series | Year: 2016

In the framework of the proposed by the author Strongly Correlated Quark Model the valence quarks are treated as vortical solitons, and the proton spin arises from the additive sum of the valence quark vorticities. The spin "crisis" is a manifestation of the irrotational character of vortical fields quarks. © Published under licence by IOP Publishing Ltd. Source

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