arXiv subjects

Goutam Sau

Publications and source records attributed to Goutam Sau.

14 recordsLinked to original sources

arXiv2014

On some properties of Deuteron and Antideuteron production in high energy lead-lead collisions at 158A GeV

We would attempt here to understand some properties of the transverse momentum ($p_T$) and rapidity ($y$) spectra on production of deuteron ($d$) and antideuteron($\overline{d}$) in lead-lead $(Pb+Pb)$ collisions at 158A GeV recently reported by NA49 collaboration. Starting from some basic properties of $p+p$ reactions for production of secondary proton-antiprotons the cases of production of the composite set of particles, like $d$ and $\overline{d}$, would be analysed. Some ratio-behaviours would also be dealt with in the light of the same approaches. It is found that the combination of the models put into use here capture modestly well the trends of the data on some important observables. Some limitations of the approach would also be pointed out in the end.

nucl-th↗

arXiv2012

On the Special Significance of the Latest PAMELA Results in Astroparticle Physics

In continuation of their earlier measurements, the PAMELA group reported data on antiproton flux and $\bar{P}/P$ ratios in 2010 at much higher energies. In past we had dealt with these specific aspects of PAMELA data in great detail and each time we captured the contemporary data-trends quite successfully with the help of a multiple production model of secondary antiprotons with some non-standard ilk and with some other absolutely standard assumptions and approximations. In this work we aim at presenting a comprehensive and valid description of all the available data on antiproton flux and the nature of $\bar{P}/P$ ratios at the highest energies reported so far by the PAMELA experiment in 2010. The main physical implication of all this would, in the end, be highlighted.

astro-ph.HE↗

arXiv2012

Production of J/$Ψ$-Particles at RHIC and LHC energies: An Alternative `Psi'-chology

We attempt here to understand successfully some crucial aspects of $J/Ψ$-production in some high energy nuclear collisions in the light of a non-standard framework outlined in the text. It is found that the results arrived at with this main working approach here is fairly in good agreement with both the measured data and the results obtained on the basis of some other models of the `standard' variety. Impact and implications of this comparative study have also been precisely highlighted in the end.

hep-ph↗

arXiv2012

Ansatzs, Assumptions and Production of J/$Ψ$-Particles: A Non-`Charmed' Approach vs. the `Charmed' Ones

We would attempt, in this work, at dwelling upon some crucial aspects of $J/Ψ$-production in a few high energy nuclear collisions in the light of a non-standard model which is outlined in the text. The underlying physical ideas, assumptions and ansatzs have also been enunciated in some detail. It is found that the results arrived at with this main working approach here are fairly in good agreement with both the measured data and the results obtained on the basis of some other models of the `standard' variety. Impact and implications of this comparative study have also been precisely highlighted in the end.

hep-ph↗

arXiv2012

Characteristics of Strange Hadron Production in Some High Energy Collisions and The Role of Power Laws

Studies on `strange' particle production have always occupied a very important space in the domain of Particle Physics. This was and is so, just because of some conjectures about specially abundant or excess production of `strange' particles, at certain stages and under certain conditions arising out of what goes by the name of `Standard' model in Particle Physics. With the help of Hagedornian power laws we have attempted to understand and interpret here the nature of the $p_T$-spectra for the strange particle production in a few high energy nuclear collisions, some interesting ratio-behaviours and the characteristics of the nuclear modification factors that are measured in laboratory experiments. After obtaining and analysing the final results we do not confront any peculiarities or oddities or extraneous excesses in the properties of the relevant observables with no left-over problems or puzzles. The model(s) used by us work(s) quite well for explaining the measured data.

hep-ph↗

arXiv2011

Rapidity and Pseudorapidity distributions of the Various Hadron-Species Produced in High Energy Nuclear Collisions : A Systematic Approach

With the help of a phenomenological approach outlined in the text in some detail, we have dealt here with the description of the plots on rapidity and pseudorapidity spectra of some hadron-secondaries produced in various nucleus-nucleus interactions at high energies. The agreement between the measured data and the attempted fits are, on the whole, modestly satisfactory excepting a very narrow central region in the vicinity of y=$η$=0. At last, hints to how the steps suggested in the main body of the text to proceed with the description of the measured data given in the plots could lead finally to a somewhat systematic methodology have also been made.

hep-ph↗

arXiv2011

On Production of Hadrons in Proton-Proton Collisions at RHIC and LHC Energies and an Approach

From the very early days of Particle Physics, both experimental and theoretical studies on proton-proton collisions had occupied the center-stage of attention for very simple and obvious reasons. And this intense interest seems now to be at peak value with the onset of the Large Hadron Collider (LHC)-studies at TeV ranges of energies. In this work, we have chosen to analyse the inclusive cross-sections, the rapidity density, the $K/π$ and $p/π$-ratio behaviours and the $ $-values, in the light of the Sequential Chain Model (SCM). And the limited successes of the model encourage us to take up further studies on several other aspects of topmost importance in particle physics with the same approach.

hep-ph↗

arXiv2011

On Production of `Soft' Particles in Au+Au and Pb+Pb Collisions at High Energies

Production of low-$p_T$ (soft) hadronic particles in high energy collisions constitutes a significant corner of special interests and problems, as the perturbative quantum chromodynamics (pQCD) does not work in this region. We have probed here into the nature of the light particle production in two symmetric nuclear collisions at two neighbouring energies with the help of two non-standard models. The results are found to be in good agreement with data. Despite this, as the models applied here are not intended to provide deep insights into the actual physical processes involved in such collisions, the phenomenological bounds and constraints which cannot be remedied for the present continue to exist.

hep-ph↗

arXiv2010

Rapidity Spectra of Heavy Baryons in Nuclear Collisions at Various Energies : A Systematic Approach

This study aims at understanding the nature of measured data on the rapidity spectra of some heavy baryons [$Λ$, $Λ$bar, $Ξ^-$ & $Ξ$bar$^+$] produced in the nuclear collisions at some modestly high energies. Furthermore, our objective is also to build up a comprehensive and consistent methodology to analyze the data on this specific observable which has a very important place in the domain of High Energy Physics (HEP). On an overall basis, our target here attains a moderate degree of success even for production of such rare secondaries. In addition to this, the limitations of such an approach have also been pointed out.

hep-ph↗

arXiv2010

Understanding the Characteristics of Multiple Production of Light Hadrons in Cu + Cu Interactions at Various RHIC Energies: A Model-based Analysis

Experiments involving copper-copper collisions at the RHIC-BNL (USA) at energies $\sqrt{s_{NN}}$ = 22.5, 62 and 200 GeV have produced a vast amount of high-precision data which are to be analysed in the light of various competing models in the domain of multiparicle production scenario. We have chosen to analyse here the measured data on the $p_T$ -spectra of various light and non-strange secondaries at various energies mentioned above, some of their very important ratio-behaviours at the various centralities of the collisions and the nuclear modification factors $R_{AA}$ and $R_{CP}$ in the light of a version of the Sequential Chain Model (SCM). The agreements between the measured data and model-based results are generally found to be modestly satisfactory. Besides, our obtained results have also been compared with results based upon two approaches with strong standard model flavour, of which one is purely pQCD-oriented and is forwarded by Vitev.

hep-ph↗

arXiv2010

On the Nature of the Rapidity-Spectra at RHIC and Some Other Energies

On the basis of the Grand Combinational Model (GCM) outlined and somewhat detailed in the text, we have attempted to capture here the several interesting assorted characteristics of the rapidity-spectra of the major varieties of secondaries produced in diverse nuclear reactions at various energies, though the main thrust of our work lies on addressing the data-trends from RHIC-BNL experiments. Obviously the core of the present approach is purely phenomenological. Still, the method and the model address the features of the data modestly well. And the method appears to have the rich potentiality, if the systematic sets of data for rapidity-studies at gradually increasing energies were available.

hep-ph↗

arXiv2010

Understanding the New High Energy Data-sets Measured by BESS, CAPRICE and PAMELA on Antiproton Flux and $\bar{P}/P$ Ratios

Reliable data from the very recent high-precision measurements on the antiproton fluxes and the antiproton-to-proton ratios by the PAMELA Collaboration at relatively much higher energies are now available. The results with regard to antiproton production phenomena spring no special surprises; rather they are sharply in contrast with and contradiction to the case of positron production at the same energy-range. However, the totality of data on antiproton production from the past experiments to the very recent PAMELA outburst seem to be a very challenging exercise for interpretation in terms of the secondary production mechanisms alone, the galactic propagation model etc against the background of the `dark-matter'-related controversy. In the present work we assume the validity of the simple leaky box model, choose a simple particle production model and attempt at providing a comprehensive interpretation of the totality of data on both antiproton flux measurements and the $\overline{P}/P$ ratio-values for the various experiments ranging from BESS, CAPRICE to the latest PAMELA experiment. With the assumption of no contribution from the exotic sources to the antiproton production process, our model and the method describe the totality of the measured data with a fair degree of success.

astro-ph.HE↗

arXiv2009

Paradigm Shifts and a Possible Resolution of the PAMELA-Paradox in Astroparticle Physics

Very recently, PAMELA Collaboration has formally reported two sets of data on positron and antiproton flux measurements done at very high energies and with unprecedented accuracy. The reports reveal a puzzle of great topical interest and importance : it is decisively found that there is a sharp smooth rise of the positron fraction, whereas for antiproton production no such rises occur; rather the fraction either flattens, or shows signs of falling off gradually with increasing energies. The present work is just an attempt to decipher the riddle with the help of a host of radically new ideas about the particle-structure, the multiparticle-production mechanisms and the concept of nucleon break-downs into the constituent partons. The application of these ideas found remarkable successes in the past; exactly similar or more striking are the findings by the present study.

astro-ph.HE↗

arXiv2009

Analysing $j/Ψ$ Production in Various RHIC Interactions with a Version of Sequential Chain Model (SCM)

We have attempted to develop here tentatively a model for $J/Ψ$ production in p+p, d+Au, Cu + Cu and Au + Au collisions at RHIC energies on the basic ansatz that the results of nucleus-nucleus collisions could be arrived at from the nucleon-nucleon (p + p)-interactions with induction of some additional specific features of high energy nuclear collisions. Based on the proposed new and somewhat unfamiliar model, we have tried (i) to capture the properties of invariant $p_T$ -spectra for $J/Ψ$ meson production; (ii) to study the nature of centrality dependence of the $p_T$ -spectra; (iii) to understand the rapidity distributions; (iv) to obtain the characteristics of the average transverse momentum $< p_T >$ and the values of $< p_T^2 >$ as well and (v) to trace the nature of nuclear modification factor. The alternative approach adopted here describes the data-sets on the above-mentioned various observables in a fairly satisfactory manner. And, finally, the nature of $J/Ψ$-production at Large Hadron Collider(LHC)-energies deduced on the basis of our chosen model has been presented in a predictive way against the RHIC-yields, both calculated for the most central collisions and on the same model.

hep-ph↗