Prabir Kumar Haldar

EVIDENCE OF FRACTAL BEHAVIOR OF PIONS AND PROTONS IN HIGH ENERGY INTERACTIONS — AN EXPERIMENTAL INVESTIGATION

Different fractal methods (Factorial moment, Takagi moment) have been used for the analysis of fractal behavior of multiparticle production in π--AgBr interaction at 350 GeV/c of compound multiplicity distribution in emission angle (cos θ) space and azimuthal angle (ϕ) space. The generalized fractal dimensions Dq are determined according to two methods. Results indicate multifractal behavior in compound multiplicity distribution. From the knowledge of Dq, the multifractal specific heat is calculated. Results are compared with the corresponding results of shower multiplicity.

Pronounced pionic self-similarity in ring-like events in 16O-AgBr interactions

This paper reports a study of ring-like and jet-like events in terms of Scaled factorial Moments (SFMs) in two-dimensional space for pions produced in 16O-AgBr interactions at 60 A GeV. The analysis reveals an intermittent type of increase in SFMs with decreasing bin width in both types of events. The analysis further shows that stronger fluctuations occur in the case of ring-like events.

Levy index analysis for a multifractality and phase transition study of target fragments in ring-like and jet-like events

In the present work, Levy indices μ are measured for target fragments for both ring-like and jet-like events in 16O–AgBr interaction at 60 AGeV and 32S–AgBr interaction at 200 AGeV. The Fq moment analysis reveals unphysical results and hence the Takagi moment analysis is adopted to get an insight into the underlying physical phenomenon. The analysis indicates different degrees of multifractality in the two types of events (ring-like and jet-like) for 32S–AgBr interaction. Also, the Levy stable law is applied to calculate the Levy index μ, which indicates different rates of cascading in different types of events.

Evidence of Strong Pion Fluctuation in Jet-Like Events in 32S–AgBr Interactions

We presents the analysis of ring-like and jet-like events in terms of Scaled Factorial Moments (SFMs) in one-dimensional space up to the sixth order of moments for 32S–AgBr interactions at 200 AGeV energy. The study reveals a power law growth of SFMs with decreasing bin width of the azimuthal distribution in the 32S–AgBr data at 200 AGeV in both the cases. It is seen that strong intermittent pattern is revealed only in jet-like events.

Factorial Correlators and Oscillatory Multiplicity Moments at the CERN SPS Energy for Ring-Like and Jet-Like Events

We present an analysis of ring-like and jet-like events in terms of factorial correlations and oscillatory multiplicity moments of 32S-Ag/Br interactions at 200 A GeV. The investigation reveals that the correlated moments increase with decrease in bin-bin separation D, following the power law, which suggests the presence of an intermittent nature of self-similar dynamical fluctuations pattern for ring-like and jet-like events. The analysis further shows that the strength of the non-statistical fluctuations is larger for jet-like events than those of ring-like events and total events. However, ring-like and jet-like events are not to be consistent with the total events of the α model of intermittency. To go beyond the lower order correlation, the oscillatory multiplicity moments are used to study the higher order correlation. The ratios Hq (cumulant over factorial moments, Kq/Fq) are determined for ring-like, jet-like and the total events. The presence of few-particle short range correlation is established. It is extremely interesting to observe that the oscillations of ring-like events are different from the jet-like events and the total events. However, in almost all the cases, the simulated interactions fail to replicate the experimental results.

MULTIFRAGMENTATIONS OF TARGETS AT SPS ENERGY — EVIDENCE OF BOTH MONOFRACTALITY AND MULTIFRACTALITY

This paper reports the fractal analysis of target residues in both ring- and jet-like events emitted from 32S-AgBr interactions at 200 AGeV using Takagis prescription. The study reveals a very interesting feature of emission process such as monofractality of target fragments in jet-like events and multifractality of target fragments in case of ring-like events.

Multifractal analysis of charged particle distributions using horizontal visibility graph and sandbox algorithm

Horizontal visibility graphs (HVGs) and the sandbox (SB) algorithm usually applied for multifractal characterization of complex network systems that are converted from time series measurements, are used to characterize the fluctuations in pseudorapidity densities of singly charged particles produced in high-energy nucleus–nucleus collisions. Besides obtaining the degree distribution associated with event-wise pseudorapidity distributions, the common set of observables, typical of any multifractality measurement, are studied in 16O-Ag/Br and 32S-Ag/Br interactions, each at an incident laboratory energy of 200 GeV/nucleon. For a better understanding, we systematically compare the experiment with a Monte Carlo model simulation based on the Ultra-relativistic Quantum Molecular Dynamics (UrQMD). Our results suggest that the HVG-SB technique is an efficient tool that can characterize multifractality in multiparticle emission data, and in some cases, it is even superior to other methods more commonly used in thi...

Strong Self-Similar Fluctuations of Target Fragments in Ring-like Events in Ultra-Relativistic Nuclear Collision

The intermittent fluctuation of target evaporated particles is studied in both ring-like and jet-like events emitted in 32S–emulsion interactions at 200 AGeV within the framework of multi-dimensional factorial moment methodology using the concept of the Hurst exponent. It is observed that the intermittent fluctuation in the ring-like event is self-similar, whereas in the jet-like event fluctuation is self-affine. However, study indicates that the strength of fluctuation in the ring-like events is much stronger than that in the jet-like events.

Non-statistical fluctuation in compound multiplicity distribution in ultrarelativistic nuclear collisions: Factorial correlator study

An investigation of non-statistical fluctuation of the compound multiplicity spectrum in 32S–AgBr interactions at 200 AGeV in terms of factorial correlators is presented. It is observed that the correlated moments increase with decrease in bin–bin separation D, following a power law, which suggests the presence of an intermittent nature of self-similar dynamical fluctuation patterns in the compound multiplicity spectrum. The data also support the α model of intermittency.

Observation of Void Probability Scaling of Proton Emission in High Energy Nucleus–Nucleus Collisions

In this paper the study of gap probability of protons has been carried out with 28Si–AgBr interaction at 14.5 A GeV in emission angle space. The study reveals the scaling behaviour of the void probability which hints towards the outer space–inner space connection. This study also confirms the validity of the linked pair approximation for the N-particle cumulant correlation functions in case of protons.