Multiplicity dependencies of midrapidity transverse momentum spectra of identified charged particles in p+p collisions at (s)1/2 = 13 TeV at LHC

2021 ◽  
pp. 2150149
Author(s):  
Khusniddin K. Olimov ◽  
Fu-Hu Liu ◽  
Kobil A. Musaev ◽  
Kosim Olimov ◽  
Boburbek J. Tukhtaev ◽  
...  
Keyword(s):  
Charged Particle ◽  
Hadron Collider ◽  
Charged Particles ◽  
Transverse Flow ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
Simple Power Function ◽  
Onset Of Deconfinement

Multiplicity dependencies of midrapidity [Formula: see text] spectra of identified charged particles in inelastic [Formula: see text] collisions at [Formula: see text] TeV at the Large Hadron Collider (LHC), measured by ALICE Collaboration, have been analyzed. The combined minimum [Formula: see text] fits with thermodynamically consistent Tsallis function as well as Hagedorn function with the embedded transverse flow describe quite satisfactorily the [Formula: see text] spectra of particles in the studied 10 different classes of charged-particle multiplicity in inelastic [Formula: see text] collisions at [Formula: see text] TeV. The obtained effective temperatures [Formula: see text] of thermodynamically consistent Tsallis function demonstrate a consistent growth with an increase in multiplicity of charged particles in inelastic [Formula: see text] collisions at [Formula: see text] TeV, and the corresponding [Formula: see text] versus the average charged-particle (pseudorapidity) multiplicity density [Formula: see text] dependence is described very well by the simple power function with exponent parameter [Formula: see text] (1/3) in the whole analyzed range [Formula: see text]. It is found that the transverse (radial) flow becomes significant at higher multiplicity events in [Formula: see text] collisions at [Formula: see text] TeV, reaching the maximum value [Formula: see text] at the largest studied multiplicity density [Formula: see text]. It is estimated from analysis of [Formula: see text] and [Formula: see text] versus [Formula: see text] dependencies, obtained using Hagedorn function with the embedded transverse flow, that the probable onset of deconfinement phase transition in inelastic [Formula: see text] collisions at [Formula: see text] TeV occurs at [Formula: see text].

scholarly journals Inferring freeze-out parameters from pion measurements at RHIC and LHC

2015 ◽  
Vol 24 (06) ◽  
pp. 1550046 ◽  
Author(s):  
Priyanka Sett ◽  
Prashant Shukla
Keyword(s):  
Transverse Momentum ◽  
System Size ◽  
Transverse Flow ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Momentum Range ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
Tsallis Distribution ◽  
Freeze Out

We analyze the transverse momentum spectra of charged pions measured in Au + Au collisions at [Formula: see text] and in Pb + Pb collisions at [Formula: see text] using the Tsallis distribution modified to include transverse flow. All the spectra are well described by the modified Tsallis distribution in an extended transverse momentum range upto 6 GeV/c. The kinetic freeze-out temperature (T), average transverse flow (β) and degree of nonthermalization (q) are obtained as a function of system size for both the energies. With increasing system size β shows increasing trend whereas T remains constant. While the systems at RHIC and LHC energies show similar β and q, the parameter T is higher at LHC as compared to RHIC. The kinetic freeze-out temperature is also extracted using the measured charged particle multiplicity and HBT volume of the system as a function of system size and collision energies.

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.

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 Charged-particle multiplicity fluctuations in Pb–Pb collisions at $$\sqrt{s_{\mathrm {NN}}}$$  = 2.76 TeV

2021 ◽  
Vol 81 (11) ◽  
Author(s):  
S. Acharya ◽  
D. Adamová ◽  
A. Adler ◽  
J. Adolfsson ◽  
G. Aglieri Rinella ◽  
...  
Keyword(s):  
Charged Particle ◽  
Multiplicity Distribution ◽  
Hadron Collider ◽  
Monte Carlo Event ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Central Collisions ◽  
The Mean ◽  
Lower Collision ◽  
Pseudorapidity Range

AbstractMeasurements of event-by-event fluctuations of charged-particle multiplicities in Pb–Pb collisions at $$\sqrt{s_{\mathrm {NN}}}$$ s NN  $$=$$ =  2.76 TeV using the ALICE detector at the CERN Large Hadron Collider (LHC) are presented in the pseudorapidity range $$|\eta |<0.8$$ | η | < 0.8 and transverse momentum $$0.2< p_{\mathrm{T}} < 2.0$$ 0.2 < p T < 2.0  GeV/c. The amplitude of the fluctuations is expressed in terms of the variance normalized by the mean of the multiplicity distribution. The $$\eta $$ η and $$p_{\mathrm{T}}$$ p T dependences of the fluctuations and their evolution with respect to collision centrality are investigated. The multiplicity fluctuations tend to decrease from peripheral to central collisions. The results are compared to those obtained from HIJING and AMPT Monte Carlo event generators as well as to experimental data at lower collision energies. Additionally, the measured multiplicity fluctuations are discussed in the context of the isothermal compressibility of the high-density strongly-interacting system formed in central Pb–Pb collisions.

scholarly journals Transverse energy and charged particle production in heavy-ion collisions: From RHIC to LHC

2014 ◽  
Vol 23 (04) ◽  
pp. 1450024 ◽  
Author(s):  
Raghunath Sahoo ◽  
Aditya Nath Mishra
Keyword(s):  
Charged Particle ◽  
Energy Production ◽  
Transverse Energy ◽  
Particle Production ◽  
Hadron Collider ◽  
Heavy Ion ◽  
Universal Function ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Relativistic Heavy Ion Collider

We study the charged particle and transverse energy production mechanism from AGS, SPS, Relativistic Heavy-Ion Collider (RHIC) to Large Hadron Collider (LHC) energies in the framework of nucleon and quark participants. At RHIC and LHC energies, the number of nucleons-normalized charged particle and transverse energy density in pseudorapidity, which shows a monotonic rise with centrality, turns out to be an almost centrality independent scaling behavior when normalized to the number of participant quarks. A universal function which is a combination of logarithmic and power-law, describes well the charged particle and transverse energy production both at nucleon and quark participant level for the whole range of collision energies. Energy dependent production mechanisms are discussed both for nucleonic and partonic level. Predictions are made for the pseudorapidity densities of transverse energy, charged particle multiplicity and their ratio (the barometric observable, [Formula: see text]) at mid-rapidity for Pb + Pb collisions at [Formula: see text]. A comparison with models based on gluon saturation and statistical hadron gas is made for the energy dependence of [Formula: see text].

Formation of clusters on relativistic charged-particle multiplicity

1990 ◽  
Vol 68 (10) ◽  
pp. 1192-1195 ◽  
Author(s):  
Tauseef Ahmad ◽  
M. Irfan ◽  
M. Z. Ahsan
Keyword(s):  
Charged Particle ◽  
Cluster Size ◽  
Charged Particles ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Nuclear Emulsions ◽  
Relativistic Charged Particle ◽  
Pion Nucleon ◽  
Nucleon Interactions

Cluster size and its dependence on the multiplicity of relativistic charged particles for pion–nucleus interactions at 340 GeV/c in nuclear emulsions are presented and compared with pion–nucleon interactions at the same energy. The maximum number of charged particles constituting a cluster has been observed to be four for events having higher multiplicity, i.e., Ns > 9, while this number turns out to be three for disintegrations with Ns ≤ 9. Finally, it may be concluded that the mechanisms of hadron–nucleus and hadron–nucleon interactions are almost identical.

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 Charged-particle production as a function of multiplicity and transverse spherocity in pp collisions at $$ \sqrt{\mathbf{s}} =\mathbf{5.02}$$ and 13 TeV

2019 ◽  
Vol 79 (10) ◽  
Author(s):  
S. Acharya ◽  
◽  
D. Adamová ◽  
S. P. Adhya ◽  
A. Adler ◽  
...  
Keyword(s):  
Charged Particle ◽  
Particle Production ◽  
Functional Form ◽  
Good Description ◽  
Charged Particles ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Pp Collisions ◽  
Kinematic Range ◽  
Charged Particle Production

Abstract We present a study of the inclusive charged-particle transverse momentum ($$p_{\mathrm{T}}$$pT) spectra as a function of charged-particle multiplicity density at mid-pseudorapidity, $$\mathrm{d}N_{\mathrm{ch}}/\mathrm{d}\eta $$dNch/dη, in pp collisions at $$\sqrt{s}=5.02$$s=5.02 and 13 TeV covering the kinematic range $$|\eta |<0.8$$|η|<0.8 and $$0.15<p_{\mathrm{T}} <20$$0.15<pT<20 GeV/c. The results are presented for events with at least one charged particle in $$|\eta |<1$$|η|<1 (INEL$$\,>0$$>0). The $$p_\mathrm{T}$$pT spectra are reported for two multiplicity estimators covering different pseudorapidity regions. The $$p_{\mathrm{T}}$$pT spectra normalized to that for INEL$$\,>0$$>0 show little energy dependence. Moreover, the high-$$p_{\mathrm{T}}$$pT yields of charged particles increase faster than the charged-particle multiplicity density. The average $${ p}_{\mathrm{T}}$$pT as a function of multiplicity and transverse spherocity is reported for pp collisions at $$\sqrt{s}=13$$s=13 TeV. For low- (high-) spherocity events, corresponding to jet-like (isotropic) events, the average $$p_\mathrm{T}$$pT is higher (smaller) than that measured in INEL$$\,>0$$>0 pp collisions. Within uncertainties, the functional form of $$\langle p_{\mathrm{T}} \rangle (N_{\mathrm{ch}})$$⟨pT⟩(Nch) is not affected by the spherocity selection. While EPOS LHC gives a good description of many features of data, PYTHIA overestimates the average $$p_{\mathrm{T}}$$pT in jet-like events.

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