scholarly journals Characterizing Proton-Proton Collisions at the Large Hadron Collider with Thermal Properties

Physics ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 207-219
Author(s):  
Dushmanta Sahu ◽  
Raghunath Sahoo
Keyword(s):  
Thermal Properties ◽  
Large Hadron Collider ◽  
Free Path ◽  
Hadron Collider ◽  
Mean Free Path ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Pp Collisions ◽  
Proton Proton ◽  
Isobaric Expansivity

High-multiplicity proton-proton (pp) collisions at the Large Hadron Collider (LHC) energies have created a new domain of research to look for a possible formation of quark–gluon plasma in these events. In this paper, we estimate various thermal properties of the matter formed in pp collisions at the LHC energies, such as mean free path, isobaric expansivity, thermal pressure, and heat capacity using a thermodynamically consistent Tsallis distribution function. Particle species-dependent mean free path and isobaric expansivity are studied as functions of final state charged particle multiplicity for pp collisions at the center-of-mass energy s = 7 TeV. The effects of degree of non-extensivity, baryochemical potential, and temperature on these thermal properties are studied. The findings are compared with the theoretical expectations.

scholarly journals Study of charged-particle multiplicity fluctuations in pp collisions with Monte Carlo event generators at the LHC

2020 ◽  
Vol 29 (09) ◽  
pp. 2050074
Author(s):  
E. Shokr ◽  
A. H. El-Farrash ◽  
A. De Roeck ◽  
M. A. Mahmoud
Keyword(s):  
Charged Particle ◽  
Particle Production ◽  
Local Density ◽  
Particle Density ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Monte Carlo Event ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Proton Proton

Proton–Proton ([Formula: see text]) collisions at the Large Hadron Collider (LHC) are simulated in order to study events with a high local density of charged particles produced in narrow pseudorapidty windows of [Formula: see text] = 0.1, 0.2, and 0.5. The [Formula: see text] collisions are generated at center of mass energies of [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] TeV, i.e., the energies at which the LHC has operated so far, using PYTHIA and HERWIG event generators. We have also studied the average of the maximum charged-particle density versus the event multiplicity for all events, using the different pseudorapidity windows. This study prepares for the multi-particle production background expected in a future search for anomalous high-density multiplicity fluctuations using the LHC data.

Modeling charged-particle multiplicity distributions at LHC

2020 ◽  
Vol 35 (36) ◽  
pp. 2050302
Author(s):  
Amr Radi
Keyword(s):  
High Energy Physics ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Charged Particles ◽  
High Energy ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
8 Tev

With many applications in high-energy physics, Deep Learning or Deep Neural Network (DNN) has become noticeable and practical in recent years. In this article, a new technique is presented for modeling the charged particles multiplicity distribution [Formula: see text] of Proton-Proton [Formula: see text] collisions using an efficient DNN model. The charged particles multiplicity n, the total center of mass energy [Formula: see text], and the pseudorapidity [Formula: see text] used as input in DNN model and the desired output is [Formula: see text]. DNN was trained to build a function, which studies the relationship between [Formula: see text]. The DNN model showed a high degree of consistency in matching the data distributions. The DNN model is used to predict with [Formula: see text] not included in the training set. The expected [Formula: see text] had effectively merged the experimental data and the values expected indicate a strong agreement with Large Hadron Collider (LHC) for ATLAS measurement at [Formula: see text], 7 and 8 TeV.

scholarly journals Estimation of the isothermal compressibility from event-by-event multiplicity fluctuation studies

2018 ◽  
Vol 171 ◽  
pp. 14010 ◽  
Author(s):  
Maitreyee Mukherjee ◽  
Sumit Basu ◽  
Sanchari Thakur ◽  
Souvik P. Adhya ◽  
Arghya Chatterjee ◽  
...  
Keyword(s):  
Charged Particle ◽  
Large Hadron Collider ◽  
Isothermal Compressibility ◽  
Hadron Collider ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Statistical Fluctuations ◽  
Wide Range ◽  
Dynamical Fluctuations ◽  
Multiplicity Fluctuation

The first estimation of the isothermal compressibility (kT) of matter is presented for a wide range of collision energies from √sNN = 7.7 GeV to 2.76 TeV. kT is estimated with the help of event-byevent charged particle multiplicity fluctuations from experiment. Dynamical fluctuations are extracted by removing the statistical fluctuations obtained from the participant model. kT is also estimated from event generators AMPT, UrQMD, EPOS and a hadron resonance gas model. The values of isothermal compressibility are estimated for the Large Hadron Collider (LHC) energies with the help of the event generators.

scholarly journals Measurement of J/Ψ production as a function of multiplicity in pp and p-Pb collisions with ALICE

2018 ◽  
Vol 182 ◽  
pp. 02064 ◽  
Author(s):  
Anisa Khatun ◽  
Keyword(s):  
Charged Particle ◽  
Theoretical Model ◽  
Electromagnetic Calorimeter ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Pp Collisions ◽  
Proton Proton ◽  
Model Predictions

The increase of hard probe production as a function of the charged particle multiplicity in proton-proton and proton-lead collisions is considered to be an interesting observable for the study of multiple parton interactions. In the present work, the correlation between J/Ψ production and charged particle multiplicity has been reviewed in pp collisions at √s = 7 and 13 TeV and p-Pb collisions at √sNN = 5.02 TeV at mid- and forward rapidities. The J/√ measurement in pp collisions at √s = 13 TeV using events triggered by the ALICE electromagnetic calorimeter at midrapidity is discussed in this report, too. An increment of the relative J/Ψ yields has been observed as a function of the multiplicity. The results have also been compared to theoretical model predictions.

scholarly journals Bose–Einstein Correlations in pp and pPb Collisions at LHCb †

Universe ◽  
2019 ◽  
Vol 5 (4) ◽  
pp. 95
Author(s):  
Bartosz Malecki
Keyword(s):  
Charged Particle ◽  
Hadron Collider ◽  
Theoretical Models ◽  
Correlation Radius ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Proton Proton ◽  
Charged Pions ◽  
Bose Einstein ◽  
Proton Proton Collisions

Bose–Einstein correlations for same-sign charged pions from proton–proton collisions at s = 7 TeV are studied by the Large Hadron Collider beauty (LHCb) experiment. Correlation radii and chaoticity parameters are determined for different regions of charged-particle multiplicity using a double-ratio technique and a Levy parametrization of the correlation function. The correlation radius increases with the charged-particle multiplicity, while the chaoticity parameter decreases, which is consistent with observations from other experiments. A similar study for proton-lead collisions at s N N = 5 . 02 TeV is proposed. These results can give valuable input for the theoretical models that describe the evolution of the particle source, probing both its potential dependence on pseudorapidity region and differences between proton–proton and proton–lead systems.

scholarly journals A Baseline Study of the Event-Shape and Multiplicity Dependence of Chemical Freeze-Out Parameters in Proton-Proton Collisions at \( {\sqrt{s}} \) = 13 TeV Using PYTHIA8

Physics ◽  
2020 ◽  
Vol 2 (4) ◽  
pp. 679-694
Author(s):  
Rutuparna Rath ◽  
Arvind Khuntia ◽  
Sushanta Tripathy ◽  
Raghunath Sahoo
Keyword(s):  
High Energy ◽  
Monte Carlo Event ◽  
Event Generator ◽  
Particle Multiplicity ◽  
Event Shape ◽  
Charged Particle Multiplicity ◽  
Pp Collisions ◽  
Proton Proton ◽  
Chemical Freeze ◽  
Freeze Out

The event-shape and multiplicity dependence of the chemical freeze-out temperature (Tch), freeze-out radius (R), and strangeness saturation factor (γs) are obtained by studying the particle yields from the PYTHIA8 Monte Carlo event generator in proton-proton (pp) collisions at the centre-of-mass s = 13 TeV. Spherocity is one of the transverse event-shape techniques to distinguish jetty and isotropic events in high-energy collisions and helps in looking into various observables in a more differential manner. In this study, spherocity classes are divided into three categories, namely (i) spherocity integrated, (ii) isotropic, and (iii) jetty. The chemical freeze-out parameters are extracted using a statistical thermal model as a function of the spherocity class and charged particle multiplicity in the canonical, strangeness canonical, and grand canonical ensembles. A clear observation of the multiplicity and spherocity class dependence of Tch, R, and γs is observed. A final state multiplicity, Nch≥ 30 in the forward multiplicity acceptance of the ALICE detector appears to be a thermodynamic limit, where the freeze-out parameters become almost independent of the ensembles. This study plays an important role in understanding the particle production mechanism in high-multiplicity pp collisions at the Large Hadron Collider (LHC) energies in view of a finite hadronic phase lifetime in small systems.

scholarly journals Multiplicity dependence of $$\pi $$, K, and p production in pp collisions at $$\sqrt{s} = 13$$ TeV

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
S. Acharya ◽  
◽  
D. Adamová ◽  
A. Adler ◽  
J. Adolfsson ◽  
...  
Keyword(s):  
Particle Production ◽  
Center Of Mass ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Mass Energy ◽  
Pp Collisions ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Particle Ratios ◽  
Rapidity Interval

Abstract This paper presents the measurements of $$\pi ^{\pm }$$π±, $$\mathrm {K}^{\pm }$$K±, $$\text {p}$$p and $$\overline{\mathrm{p}} $$p¯ transverse momentum ($$p_{\text {T}}$$pT) spectra as a function of charged-particle multiplicity density in proton–proton (pp) collisions at $$\sqrt{s}\ =\ 13\ \text {TeV}$$s=13TeV with the ALICE detector at the LHC. Such study allows us to isolate the center-of-mass energy dependence of light-flavour particle production. The measurements reported here cover a $$p_{\text {T}}$$pT range from 0.1 to 20 $$\text {GeV}/c$$GeV/c and are done in the rapidity interval $$|y|<0.5$$|y|<0.5. The $$p_{\text {T}}$$pT-differential particle ratios exhibit an evolution with multiplicity, similar to that observed in pp collisions at $$\sqrt{s}\ =\ 7\ \text {TeV}$$s=7TeV, which is qualitatively described by some of the hydrodynamical and pQCD-inspired models discussed in this paper. Furthermore, the $$p_{\text {T}}$$pT-integrated hadron-to-pion yield ratios measured in pp collisions at two different center-of-mass energies are consistent when compared at similar multiplicities. This also extends to strange and multi-strange hadrons, suggesting that, at LHC energies, particle hadrochemistry scales with particle multiplicity the same way under different collision energies and colliding systems.

scholarly journals Thermodynamic Limit in High-Multiplicity Proton-Proton Collisions at s=7 TeV

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Natasha Sharma ◽  
Jean Cleymans ◽  
Boris Hippolyte
Keyword(s):  
Thermodynamic Limit ◽  
Canonical Ensemble ◽  
Baryon Number ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Pp Collisions ◽  
Final State ◽  
Proton Proton ◽  
Rapidity Interval ◽  
Proton Proton Collisions

An analysis is made of the particle composition in the final state of proton-proton (pp) collisions at 7 TeV as a function of the charged particle multiplicity (dNch/dη). The thermal model is used to determine the chemical freeze-out temperature as well as the radius and strangeness suppression factor γs. Three different ensembles are used in the analysis: the grand canonical ensemble, the canonical ensemble with exact strangeness conservation, and the canonical ensemble with exact baryon number, strangeness, and electric charge conservation. It is shown that for the highest multiplicity class the three ensembles lead to the same result. This allows us to conclude that this multiplicity class is close to the thermodynamic limit. It is estimated that the final state in pp collisions could reach the thermodynamic limit when dNch/dη is larger than twenty per unit of rapidity, corresponding to about 300 particles in the final state when integrated over the full rapidity interval.

scholarly journals Multiplicity dependence of (multi-)strange hadron production in proton-proton collisions at $$\sqrt{s}$$ = 13 TeV

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
S. Acharya ◽  
◽  
D. Adamová ◽  
S. P. Adhya ◽  
A. Adler ◽  
...  
Keyword(s):  
Charged Particle ◽  
Charged Particles ◽  
General Purpose ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Production Rates ◽  
Proton Proton ◽  
Proton Collisions ◽  
Strange Hadron ◽  
Proton Proton Collisions

Abstract The production rates and the transverse momentum distribution of strange hadrons at mid-rapidity ($$\left| y\right| < 0.5$$y<0.5) are measured in proton-proton collisions at $$\sqrt{s}$$s = 13 TeV as a function of the charged particle multiplicity, using the ALICE detector at the LHC. The production rates of $$\mathrm{K}^{0}_{S}$$KS0, $$\Lambda $$Λ, $$\Xi $$Ξ, and $$\Omega $$Ω increase with the multiplicity faster than what is reported for inclusive charged particles. The increase is found to be more pronounced for hadrons with a larger strangeness content. Possible auto-correlations between the charged particles and the strange hadrons are evaluated by measuring the event-activity with charged particle multiplicity estimators covering different pseudorapidity regions. When comparing to lower energy results, the yields of strange hadrons are found to depend only on the mid-rapidity charged particle multiplicity. Several features of the data are reproduced qualitatively by general purpose QCD Monte Carlo models that take into account the effect of densely-packed QCD strings in high multiplicity collisions. However, none of the tested models reproduce the data quantitatively. This work corroborates and extends the ALICE findings on strangeness production in proton-proton collisions at 7 TeV.

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