BHASKAR DE
@tgc.ac.in
Associate Professor in Department of Physics
TAKI GOVERNMENT COLLEGE
RESEARCH, TEACHING, or OTHER INTERESTS
Nuclear and High Energy Physics
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Bhaskar De
Springer Science and Business Media LLC
Bhaskar De
Springer Science and Business Media LLC
BHASKAR DE, GOUTAM SAU, S. K. BISWAS, S. BHATTACHARYYA, and P. GUPTAROY
World Scientific Pub Co Pte Lt
The transverse momentum spectra of secondary η particles produced in P+P, D + Au and Au + Au interactions at [Formula: see text] at different centralities have been studied in the light of a nonextensive thermodynamical approach. The results and the possible thermodynamical insights, thus obtained, about the hadronizing process have also been discussed in detail.
Goutam Sau, S. K. Biswas, Bhaskar De, P. Guptaroy, A. Bhattacharya, and S. Bhattacharyya
Canadian Science Publishing
In continuation of our series of works on the phenomenological studies on production of particles in various high-energy collisions, we attempt here to deal exclusively with some very crucial aspects of Au–Au collisions at RHIC-BNL. With emphasis on understanding the qualitative and quantitative properties of several important observables related to Au–Au interactions at RHIC, we have also endeavored to analyze and assess, if possible, the limits to the successes and failures of such absolutely phenomenological approaches. As all the models in the domain of high-energy physics are invariably and essentially phenomenological in nature, we have also tried to pinpoint the main and major constrictions of and constraints on these approaches-cum-models. By this yardstick, even the so-called Standard Model (SM), which is too greatly lauded and taken for granted, cannot escape our critical remarks that are cast on the general framework of what is termed “phenomenology”, in the realm of physics in particular and of science in general.
S K Biswas, G Sau, P Guptaroy, B De, A Bhattacharya, and S Bhattacharyya
Canadian Science Publishing
The measured data on transverse momentum spectra for production of direct photons in hadron–hadron, hadron–nucleus, and nucleus–nucleus interactions at high energies are compiled. Besides, data on some other aspects related to these pT-spectra are also assorted in the present work. The pT-spectra for production of direct photons at pT > 1 GeV/c are, then, fitted here by using two parameterizations, which essentially approach the power-law dependence at high transverse momenta. The power indices range between 16 to 7 depending on the interacting particles and the centre-of-mass energy of the system. The power index decreases gradually with increasing energy, with a variation of the rate of fall for various energy ranges. The formulae applied here phenomenologically bring out the main features of the data characteristics in a modestly satisfactory manner. This provokes us to raise some serious questions about the existing “theoretical” approaches, all, or most of which, lack in the first-principle derivations of the actual working expressions used to finally describe the nature of the measured data on direct photons, or for that matter, on any other secondary particle.PACS Nos.: 25.75.–q, 12.38.Mh, 13.85.Ni
G Sau, S K Biswas, B De, P Guptaroy, A Bhattacharya, and S Bhattacharyya
Canadian Science Publishing
Interpretation and understanding of high-energy PP data in a clear, consistent, and comprehensive manner is crucial for making valid claims to build up any successful theoretical framework for particle interactions. We have tried here to analyze the various sets of PP data available from the pre-ISR days to the latest PP collisions at the relativistic heavy ion collider (RHIC) experiment at [Formula: see text] = 200 GeV in the light of a power-law model. Both mid-rapidity and high-rapidity data sets have been dealt with by applying the same working formula. It is found that the working formula used provides a good description of these wide ranging data sets; but hardly throws any deep insights into the nature of particle interactions that force us to question the worth and rigour of phenomenological studies.PACS Nos.: 13.60.Hb, 13.60.Le, 13.85.Ni
G Sau, S K Biswas, B De, P Guptaroy, A Bhattacharya, and S Bhattacharyya
Canadian Science Publishing
Our focus in this work would be concentrated on trying to understand the nature of some very important observables measured for deuteron–gold (d + Au) collisions at relativistic heavy ion collider (RHIC) energies in the light of a particular phenomenological model that we had applied earlier in analyzing data for PP collisions at RHIC and Fermi National Accelerator Laboratory (FNAL) energies with a fair degree of success. In this particular case, as well, our observations and conclusions are exactly similar to those in our previous work. The emphatic ending points, on the whole, to some gross limitations of the chosen phenomenological approach in particular and of the phenomenology as such in general.PACS Nos.: 13.60.Hb, 13.60.Le, 13.60.Rj, 13.85.Ni
P. GUPTAROY, BHASKAR DE, GOUTAM SAU, S. K. BISWAS, and S. BHATTACHARYYA
World Scientific Pub Co Pte Lt
Experimental studies on gold–gold collisions at RHIC at [Formula: see text] have produced a vast amount of data and results to be analyzed in the light of various competing models in the domain of multiparticle production scenario. We have chosen to analyze here the measured data on the pT-spectra of various light and nonstrange secondaries and some of their very important ratio-behaviors at the various centralities of the collision in the light of a version of the sequential chain model. The agreements between measured data and theoretical plots are found to be modestly satisfactory.
BHASKAR DE, S. BHATTACHARYYA, GOUTAM SAU, and S. K. BISWAS
World Scientific Pub Co Pte Lt
In the light of ideas of the nonextensive thermodynamics, we have analyzed here the transverse momentum spectra of pions and protons produced at different centralities in the interactions of P+P, D+Au and Au+Au interactions, all of them at [Formula: see text] GeV at RHIC-BNL. Comparison of the results and the comments thereon have also been made with indications of suitable hints to the physical import and implications. The overall impact and the utility of the approach along with the obtained results are discussed in detail.
S. K. BISWAS, BHASKAR DE, P. GUPTAROY, A. BHATTACHARYA, and S. BHATTACHARYYA
World Scientific Pub Co Pte Lt
In the present study on proton–Beryllium collisions at two distinctly different energies obtained by one FERMILAB Collaboration, we attempt to focus on the unsettled controversy between the exponential models versus power law models, both of which are found to be in wide applications. The study concludes that none of them could be abandoned finally. And the resolution of the debate, the authors argue, might rest, not on the acceptance of just any one of them, but on a suitable combination of both of them, acting in the different domains of the transverse momentum values.
BHASKAR DE, S. K. BISWAS, and S. BHATTACHARYYA
World Scientific Pub Co Pte Lt
The present work is an attempt to analyze some of the so-called problematical aspects of both the AuAu and PbPb collisions at high energies. In the framework of a phenomenological theory, called here the combinational approach (CA), we have attempted to obtain in this work the nature of the ratios of (i) invariant cross-sections in AuAu and PbPb reactions to the binary-scaled PP interaction cross-section values and (ii) the latest spurt of values on secondary proton-to-pion (p/π) ratios which have stirred much excitements recently. To our surprise, at least up to nearly pT = 4 GeV/c , we find no exotic or novel nuclear-medium effects with regard to the explanation for both observations. And in this domain it is seen that our model reproduces the reported experimental features modestly well. However, the region beyond pT = 4 GeV/c apparently necessitates introduction of various second-order effects arising out of multiple collisions involving the interacting partons; and needs to be explored separately by more detailed and in-depth future studies.
BHASKAR DE, S. K. BISWAS, and S. BHATTACHARYYA
World Scientific Pub Co Pte Lt
The measured data on production of π0 and η mesons at large transverse momenta in high energy π-P and π-Be interactions have here been analyzed with the help of a newly-developed phenomenological model, called Combinational Approach(CA). The results so obtained on the basis of the CA are seen to be in fair agreement with the measured data. Furthermore, the results so obtained have been compared with both some previous measuremnts by the same group and some models of the standard variety type, e.g., PYTHIA, HERWIG.
BHASKAR DE, S. K. BISWAS, and S. BHATTACHARYYA
World Scientific Pub Co Pte Lt
BRAHMS collaboration1 had studied in the recent past some properties of the detected identified charged hadrons in gold–gold collisions at [Formula: see text] as a function of pT and collision-centrality at two rapidity values. The reported characteristics, which are not offshoots of any specific model whatsoever, and are measured in a model-independent manner, would be dealt with in the light of a phenomenological framework named combinational approach.
BHASKAR DE and S. BHATTACHARYYA
World Scientific Pub Co Pte Lt
The contrasting nature of the pT-spectra measured in deuteron ( D )–gold ( Au ) and gold ( Au )–gold ( Au ) collisions, both performed at RHIC-BNL at [Formula: see text], is now considered to be a very stimulating and hot topic in the domain of high energy nuclear physics. In continuation of our efforts to understand the measured data in high energy nuclear collisions in a somewhat nonstandard and alternative way, called the Combinational Approach (CA), we try here first to understand and reproduce the latest observations on deuteron–gold collisions at [Formula: see text] at mid-rapidity and some other rapidity regions with the same. Besides, (i) we also bring out the features of contrast for nuclear modification factor (NMF) in Au Au collisions at [Formula: see text]; (ii) for cross-checking of the present and previous results we also obtain the hadronic ratios measured for only the Au Au collisions at [Formula: see text], as the data on the similar ratios for D Au interactions are not yet available. Finally, we point out the implications of the approach in terms of both data-interpretation and physical insights.
P. GUPTAROY, GOURI SANYAL, BHASKAR DE, and S. BHATTACHARYYA
World Scientific Pub Co Pte Lt
The oncoming recent data on production of J/Ψ mesons in some high energy particle and nuclear collisions are of special importance in view of the controversies centering around the so-called suppression or enhancement mechanisms for this particle-species. We will try to explain here the features of some of the basic observables on J/Ψ production with the help of an approach which has no direct links with quark–gluon plasma (QGP) considerations, but can interpret a large amount of data related to the proposed physical signatures of QGP. The final outcome, based on the present study, amounts to stating the fact that the J/Ψ production is neither suppressed nor enhanced; rather it exhibits both in our theoretical approach and also in the experimental measurements a behavior which is just as normal as many other secondaries, with only specificities of its own intrinsic quantum numbers and the very massive nature.
Bhaskar De and S. Bhattacharyya
American Physical Society (APS)
The present study is both a reanalysis and an extension of the approach initiated by S. Eremin and S. Voloshin [Phys. Rev. C, 67, 064905 (2003)]. We attempt to interpret here the rapidity spectra of the various particles produced in both $\\mathrm{Pb}+\\mathrm{Pb}$ and $\\mathrm{Au}+\\mathrm{Au}$ collisions at SPS-CERN (Super Proton Synchrotron at Conseil Europ\\'een pour la Recherche Nucl\\'eaire) and RHIC-BNL (Relativistic Heavy Ion Collider at Brookhaven National Laboratory). The study made here is wider in scope and is more species specific than earlier ones, and the results obtained here are compared with those found in previous works based on HIJING, VENUS, etc., at various centralities. The study reconfirms that the constituent parton picture of the particles provides a better and more unified description of the rapidity-density yields for the various secondaries, including some light cluster particles such as deuteron, even in heavy ion collisions.
BHASKAR DE and S. BHATTACHARYYA
World Scientific Pub Co Pte Lt
In continuation of our perusal of the studies on transverse momentum spectra for the main varieties of secondaries from a consistent and comprehensive phenomenological approach, we propose to take up here — after a successful completion of reporting in detail the results (Ref. 4 in the text) on our analyses of the pT-spectra of pions — the studies specially on production of kaons, protons and antiprotons in several proton-induced and nucleus-involved collisions at high energies. The measured data on inclusive cross-sections of kaons, protons and antiprotons from the various published sources have here been assorted first. Next, data on the pT-spectra of the specific secondaries produced in PP and [Formula: see text] reactions have been scanned and analyzed with the help of Hagedorn's model (HM). Thereafter a connector, named here the combinational approach (CA), has been constructed and used to analyze the data on pT-spectra of some major category of non-pion secondaries produced in nucleus–nucleus (AA/AB) collisions at high energies. And these exercises have, finally, led to the modestly successful interpretations of a wide band of data with the revelation of some insightful physical aspects of high energy interactions. The limitations of the approach have also been precisely pointed out in the end.
BHASKAR DE and S. BHATTACHARYYA
World Scientific Pub Co Pte Lt
We would try, in the present work, to understand the nature of the rapidity spectra of the major categories of the secondaries produced in NN, NA and AB collisions at high energies from the viewpoint of a combinational approach, called chosen combination of models (CCM), proposed very recently by the same authors. Despite several difficulties pertaining to the availability of reliable data and the large ranges of uncertainties of measurements in many cases in the reported data, we have reproduced here the measured behavior of the data-sets with a modest degree of success.
BHASKAR DE and S. BHATTACHARYYA
World Scientific Pub Co Pte Lt
In the light of a newly proposed phenomenological model offered by the combinational approach, we attempt to interpret with a modest degree of success the measured data on production of the pT-spectra of the lambda (Λ) baryons and phi (Φ) mesons in some heavy-ion collisions. The choices of the specific varieties for the present study are influenced by the two factors: (i) availability of data in [Formula: see text] reactions at some high energies and also in a few heavy-ion collisions at several energies; and (ii) the status and importance of the specific particle(s) from various physical considerations.
Bhaskar De and S. Bhattacharyya
Springer Science and Business Media LLC
P. GUPTAROY, BHASKAR DE, and S. BHATTACHARYYA
World Scientific Pub Co Pte Lt
This work is in response to the stimulus received from our fairly successful attempt at understanding in the recent past the problem of direct photon production only in gold–gold and lead–lead collisions from the viewpoint of a non-standard approach. The same nonconventional formalism would, once again, be applied to analyze the vast array of measurements on the inclusive cross sections of direct photons produced in several purely nuclear or hadronuclear collisions at very high energies. Besides, some of the cross section ratios would also be calculated and be compared with data on them. All this reveals and indicates a modest agreement between the model-based calculations and the actual measurements. The authors would also endeavor here to adduce the reasons for the discrepancies, if any.
P. Guptaroy, Bhaskar De, S. Bhattacharyya, and D. P. Bhattacharyya
World Scientific Pub Co Pte Lt
The study presented here pertains to the model-based analyses for production of some important charged secondaries in lead-lead and gold-gold collisions at AGS, SPS and RHIC energies. We examine the role of a particular version of the Sequential Chain Model (SCM) in interpreting the data on the production of only the secondary mesons of the most abundant variety in relativistic nucleus-nucleus collisions. The initial results derived for basic pp collisions have been transformed into the corresponding cases for nucleus-nucleus collisions through the appropriate physical-mathematical formalisms. The agreement between the model of choice and the measured data for the most important varieties of mesons in the two above-stated nuclear collisions could so far be rated to be barely modest. This is presumably due to our neglect of the effects of rescattering and cascading, while we choose to obtain only the first-order results in the initial attempt.
Bhaskar De and S. Bhattacharyya
World Scientific Pub Co Pte Lt
The nature of invariant cross-sections and multiplicities in some 208Pb-induced reactions and some important ratio behaviors of the invariant multiplicities for various centralities of the collision will be dealt with here in the light of a combinational approach which has been built up recently by us. Next, the results would be compared with the outcome of some of the simulation-based standard models for multiple production in nuclear collisions at high energies. Finally, the implications of all this would be discussed.
BHASKAR DE, S. BHATTACHARYYA, and P. GUPTAROY
World Scientific Pub Co Pte Lt
The RHIC measurements on the transverse momentum spectra of the main category of secondary particles produced in the Au + Au collisions were reported in the recent past. The combination of the phenomenological approaches we adopted provide a satisfactory, alternative framework for understanding and explaining the latest data-spurts on charged pions, kaons and the protons–antiprotons. The comparison of the performances by the contesting models on a select kind of secondary (π+) which belongs to the most abundant variety has also been made. The impact and implications of all these have also been spelt out in the end.
P. Guptaroy, Bhaskar De, and S. Bhattacharyya
Springer Science and Business Media LLC
We attempt in this paper to deal with some aspects of the direct photon production phenomenon mainly in the Pb+Pb and Au+Au collisions on the basis of a model for production of the same particle species in PP collisions. The results have, thereafter, been converted to those for a few AB/AA interactions through an appropriate mechanism. Comparison of the theoretical results obtained on the basis of model-based calculations with measured data on the relevant observables leads to a fair agreement between them. This reflects modestly the fair achievements attained by the models that are made use of in the present work.