arXiv subjects

C. Besliu

Publications and source records attributed to C. Besliu.

16 recordsLinked to original sources

arXiv2018

Implementation of quark confinement, and retarded interactions algorithms for Chaos Many-Body Engine

In Grossu et al. (2012) we presented a Chaos Many-Body Engine (CMBE) toy-model for chaos analysis of relativistic nuclear collisions at 4.5 A GeV/c (the SKM 200 collaboration) which was later extended to Cu + Cu collisions at the maximum BNL energy. Inspired by existing quark billiards, the main goal of this work was extending CMBE to partons. Thus, we first implemented a confinement algorithm founded on some intuitive assumptions: 1) the system can be decomposed into a set of two or three-body quark white clusters; 2) the bi-particle force is limited to the domain of each cluster; 3) the physical solution conforms to the minimum potential energy requirement. Color conservation was also treated as part of the reactions logic module. As an example of use, we proposed a toy-model for p + p collisions at sqrt(s)=10 GeV and we compared it with HIJING. Another direction of interest was related to retarded interactions. Following this purpose, we implemented an Euler retarded algorithm and we tested it on a simple two-body system with attractive inverse-square-law force. First results suggest that retarded interactions may contribute to the Virial theorem anomalies (dark matter) encountered for gravitational systems (e.g. clusters of galaxies). On the other hand, the time reverse functionality implemented in CMBE v03 could be used together with retardation for analyzing the Loschmidt paradox. Regarding the application design, it is important to mention the code was refactored to SOLID. In this context, we have also written more than one hundred unit and integration tests, which represent an important indicator of application logic validity.

physics.comp-ph↗

arXiv2016

Rapidity and centrality dependence of particle production for identified hadrons in Cu+Cu collisions at $\sqrt{s_{NN}} = 200$ GeV

The BRAHMS collaboration has measured transverse momentum spectra of pions, kaons, protons and antiprotons at rapidities 0 and 3 for Cu+Cu collisions at $\sqrt{s_{NN}} = 200$ GeV. As the collisions become more central the collective radial flow increases while the temperature of kinetic freeze-out decreases. The temperature is lower and the radial flow weaker at forward rapidity. Pion and kaon yields with transverse momenta between 1.5 and 2.5 GeV/c are suppressed for central collisions relative to scaled $p+p$ collisions. This suppression, which increases as the collisions become more central is consistent with jet quenching models and is also present with comparable magnitude at forward rapidity. At such rapidities initial state effects may also be present and persistence of the meson suppression to high rapidity may reflect a combination of jet quenching and nuclear shadowing. The ratio of protons to mesons increases as the collisions become more central and is largest at forward rapidities.

nucl-ex↗

arXiv2013

High precision framework for Chaos Many-Body Engine

In this paper we present a C# 4.0 high precision framework for simulation of relativistic many-body systems. In order to benefit from, previously developed, chaos analysis instruments, all new modules were designed to be integrated with Chaos Many-Body Engine [1,3]. As a direct application, we used 46 digits precision for analyzing the Butterfly Effect of the gravitational force in a specific relativistic nuclear collision toy-model. Trying to investigate the average Lyapunov Exponent dependency on the incident momentum, an interesting case of intermittency was noticed. Based on the same framework, other high-precision simulations are currently in progress (e.g. study on the possibility of considering, hard to detect, extremely low frequency photons as one of the dark matter components).

physics.comp-ph↗

arXiv2011

Rapidity dependence of deuteron production in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

We have measured the distributions of protons and deuterons produced in high energy heavy ion Au+Au collisions at RHIC over a very wide range of transverse and longitudinal momentum. Near mid-rapidity we have also measured the distribution of anti-protons and anti-deuterons. We present our results in the context of coalescence models. In particular we extract the "volume of homogeneity" and the average phase-space density for protons and anti-protons. Near central rapidity the coalescence parameter $B_2(p_T)$ and the space averaged phase-space density $ (p_T)$ are very similar for both protons and anti-protons. For protons we see little variation of either $B_2(p_T)$ or the space averaged phase-space density as the rapidity increases from 0 to 3. However both these quantities depend strongly on $p_T$ at all rapidities. These results are in contrast to lower energy data where the proton and anti-proton phase-space densities are different at $y$=0 and both $B_2$ and $f$ depend strongly on rapidity.

nucl-ex↗

arXiv2010

Code C# for chaos analysis of relativistic many-body systems with reactions

In this work we present a reactions module for "Chaos Many-Body Engine" (Grossu et al., 2010 [1]). Following our goal of creating a customizable, object oriented code library, the list of all possible reactions, including the corresponding properties (particle types, probability, cross-section, particles lifetime etc.), could be supplied as parameter, using a specific XML input file. Inspired by the Poincare section, we propose also the "Clusterization map", as a new intuitive analysis method of many-body systems. For exemplification, we implemented a numerical toy-model for nuclear relativistic collisions at 4.5 A GeV/c (the SKM200 collaboration). An encouraging agreement with experimental data was obtained for momentum, energy, rapidity, and angular π- distributions.

physics.comp-ph↗

arXiv2010

Code C# for chaos analysis of relativistic many-body systems

This work presents a new Microsoft Visual C# .NET code library, conceived as a general object oriented solution for chaos analysis of three-dimensional, relativistic many-body systems. In this context, we implemented the Lyapunov exponent and the "fragmentation level" (defined using the graph theory and the Shannon entropy). Inspired by existing studies on billiard nuclear models and clusters of galaxies, we tried to apply the virial theorem for a simplified many-body system composed by nucleons. A possible application of the "virial coefficient" to the stability analysis of chaotic systems is also discussed.

physics.comp-ph↗

arXiv2010

Semiclassical study on Proton and Neutron

Starting from the existing semiclassical studies on hydrogenoid atoms, we propose a similar intuitive exercise for the three-body quark systems corresponding to protons and neutrons. In the frame of this toy model we try to explain both the stabilities of proton and neutron with respect to the nuclear interaction, and the spectrum of nucleonic resonances with J=1/2. Our choice is motivated also by a good agreement obtained for the up and down quark rest masses report. Taking into account the deterministic chaotic behavior of many-body systems, the discussed exercise could be understood as an interesting particular case of a quantum three-body problem which admits a semiclassical treatment.

nucl-th↗

arXiv2009

Visual tool for estimating the fractal dimension of images

This work presents a new Visual Basic 6.0 application for estimating the fractal dimension of images, based on an optimized version of the box-counting algorithm. Following the attempt to separate the real information from noise, we considered also the family of all band-pass filters with the same band-width (specified as parameter). The fractal dimension can be thus represented as a function of the pixel color code. The program was used for the study of paintings cracks, as an additional tool which can help the critic to decide if an artistic work is original or not. In its second version, the application was extended for working also with csv files and three-dimensional images.

physics.comp-ph↗

arXiv2009

Intermittency route to chaos for the nuclear billiard - a quantitative study

We extended a previous qualitative study of the intermittent behaviour of a chaotical nucleonic system, by adding a few quantitative analyses: of the configuration and kinetic energy spaces, power spectra, Shannon entropies, and Lyapunov exponents. The system is regarded as a classical "nuclear billiard" with an oscillating surface of a 2D Woods-Saxon potential well. For the monopole and dipole vibrational modes we bring new arguments in favour of the idea that the degree of chaoticity increases when shifting the oscillation frequency from the adiabatic to the resonance stage of the interaction. The order-chaos-order-chaos sequence is also thoroughly investigated and we find that, for the monopole deformation case, an intermittency pattern is again found. Moreover, coupling between one-nucleon and collective degrees of freedom is proved to be essential in obtaining chaotic states.

nucl-th↗

arXiv2009

Intermittency route to chaos for the nuclear billiard - a qualitative study

We analyze on a simple classical billiard system the onset of chaotical behaviour in different dynamical states. A classical version of the "nuclear billiard" with a 2D deep Woods-Saxon potential is used. We take into account the coupling between the single-particle and the collective degrees of freedom in the presence of dissipation for several vibrational multipolarities. For the considered oscillation modes an increasing divergence of the nucleonic trajectories from the adiabatic to the resonance regime was observed. Also, a peculiar case of intermittency is reached in the vicinity of the resonance, for the monopole case. We examine the order-to-chaos transition by performing several types of qualitative analysis including sensitive dependence on the initial conditions, single-particle phase space maps, fractal dimensions of Poincare maps and autocorrelation functions.

nucl-th↗

arXiv2009

Some phenomenological considerations on the nuclear collisions at high energies

We present some results obtained by applying the chaos theory on the numerical study of one threedimensional, relativistic, many-body quark system. The asymptotic freedom property is introduced by employing a harmonic term in the bi-particle potential. In this context, we used also the outcome of a semiclassical study, applied to the quark constituents of nucleons. Depending on the initial temperature parameter, the system can evolve toward an oscillating or an expansion regime. It is important to notice also a transition region, characterized by a partial fragmentation (higher degree of order). This effect can be observed near the critical temperature and is related to the partial overcoming of the potential barrier (corresponding to the farthest particles from the system). The degree of fragmentation is defined on the Shannon entropy basis and using the graphs theory. For analyzing the expansion tendency of one relativistic many-body system, we employed also the virial coefficient.

hep-ph↗

arXiv2008

On The Leptons Masses

In this paper we present a connection between the results obtained from a semiclassical study of a relativistic, two-body system, and the leptons masses. Some possible consequences are also discussed.

nucl-th↗

arXiv2006

Rapidity dependence of high p_T suppression at sqrt{s_{NN}}=62.4{GeV}

We present measurements of charged hadron p_T spectra from Au+Au collisions at sqrt(snn)=62.4 GeV for pseudorapidities eta=0, eta=1 and eta=3.2. Around midrapidity (eta=0, eta=1) we find nuclear modification factors at levels suggesting a smaller degree of high p_T suppression than in the same reaction at higher energy sqrt(snn)=200 GeV. At the high pseudorapidity, eta=3.2, where nuclear modification factors cannot be constructed due to the lack of p+p reference data, we find a significant reduction of R_{CP} (central to peripheral ratio) as compared to midrapidity.

nucl-ex↗

arXiv1999

Trace Analysis of Ancient Gold Objects Using Radiochemical Neutron Activation

Radiochemical neutron activation analysis has been applied to investigate the microelements in gold samples with archaeological importance. Chemical separation has allowed the determination of traces of Ir, Os, Sb, Zn, Co, Fe, Ni. Instrumental neutron activation analysis has been used for the determination of Cu.

nucl-ex↗

arXiv1999

Compositional Studies of Ancient Copper from Romanian Territories

Ancient copper objects from Romanian Territories have been analyzed by neutron activation analysis. A series of elements is determined: Au, Ag, As, Co, Cr, Fe, Hg, Ni, Zn, Sb, Sc, Se, Sn. Using mathematical dendograms some classifications and correlation have been established.

nucl-ex↗

arXiv1993

Do Search for Dibaryonic De - Excitations in Relativistic Nuclear Reactions

Some odd characteristics are observed in the single particle distributions obtained from $ He + Li $ interactions at $ 4.5 AGeV/c $ momenta which are explained as the manifestation of a new mechanism of strangeness production via dibaryonic de-excitations. A signature of the formation of hadronic and baryonic clusters is also reported. The di-pionic signals of the dibaryonic orbital de-excitations are analyzed in the frame of the MIT - bag Model and a Monte Carlo simulation.The role played by the dibaryonic resonances in relativistic nuclear collisions could be a significant one. Key words: Relativistic nuclear interactions negative pions, negative kaons, di-pions , streamer chamber, dibaryons, MIT - bag model PACS codes: 25.75.+r,14.40.Aq,14.20.Pt,12.40.As

hep-ph↗