scholarly journals Correlation between heavy flavour production and multiplicity in pp and p-Pb collisions at high energy in the multi-pomeron exchange model

2018 ◽  
Vol 171 ◽  
pp. 18003 ◽  
Author(s):  
Grigory Feofilov ◽  
Vladimir Kovalenko ◽  
Andrei Puchkov
Keyword(s):  
String Tension ◽  
High Energy ◽  
Exchange Model ◽  
Pomeron Exchange ◽  
Strength Parameter ◽  
Wide Energy Range ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Pp Collisions ◽  
Wide Energy

The multiplicity dependence of heavy flavour production in pp-collisions at LHC energies is studied in the framework of the multi-pomeron exchange model. The model is introducing the string-string interaction collectivity effects in pp collisions, which modifies multiplicity and transverse momenta, leading to the non-trivial mean pt vs. multiplicity (〈pt〉Nch − Nch). correlation. The string collectivity strength parameter is fixed by experimental data on multiplicity and transverse momentum correlation in a wide energy range (from ISR to LHC). The particles discrimination is implemented according to Schwinger mechanism taking into account the strong decays of hadron resonances. We demonstrate, that the faster-than-linear growth of the open charm production with the event charged particle multiplicity, observed in experimental pp high energy collisions, can be explained by the modification of the string tension due to the increasing overlap and interaction of quark-gluon strings. The model is extended for p-A interactions and the calculations for p-Pb collisions are performed.

scholarly journals (Anti-)deuteron production in pp collisions at $$\sqrt{s}=13 \ \text {TeV}$$

2020 ◽  
Vol 80 (9) ◽  
Author(s):  
S. Acharya ◽  
◽  
D. Adamová ◽  
A. Adler ◽  
J. Adolfsson ◽  
...  
Keyword(s):  
Charged Particle ◽  
Formation Mechanism ◽  
Bound States ◽  
High Energy ◽  
Light Nuclei ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Pp Collisions ◽  
Alice Experiment ◽  
Deuteron Production

AbstractThe study of (anti-)deuteron production in pp collisions has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high-energy hadronic collisions. In this paper the production of $$\text {(anti-)deuterons}$$ (anti-)deuterons is studied as a function of the charged particle multiplicity in inelastic pp collisions at $$\sqrt{s}=13$$ s = 13 TeV using the ALICE experiment. Thanks to the large number of accumulated minimum bias events, it has been possible to measure (anti-)deuteron production in pp collisions up to the same charged particle multiplicity ($${\mathrm {d} N_{ch}/\mathrm {d} \eta } \sim 26$$ d N ch / d η ∼ 26 ) as measured in p–Pb collisions at similar centre-of-mass energies. Within the uncertainties, the deuteron yield in pp collisions resembles the one in p–Pb interactions, suggesting a common formation mechanism behind the production of light nuclei in hadronic interactions. In this context the measurements are compared with the expectations of coalescence and statistical hadronisation models (SHM).

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.

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 Freeze-Out Parameters in Heavy-Ion Collisions at AGS, SPS, RHIC, and LHC Energies

2015 ◽  
Vol 2015 ◽  
pp. 1-20 ◽  
Author(s):  
Sandeep Chatterjee ◽  
Sabita Das ◽  
Lokesh Kumar ◽  
D. Mishra ◽  
Bedangadas Mohanty ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
High Energy ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Ion Collisions ◽  
Momentum Distributions ◽  
Chemical Freeze ◽  
Freeze Out

We review the chemical and kinetic freeze-out conditions in high energy heavy-ion collisions for AGS, SPS, RHIC, and LHC energies. Chemical freeze-out parameters are obtained using produced particle yields in central collisions while the corresponding kinetic freeze-out parameters are obtained using transverse momentum distributions of produced particles. For chemical freeze-out, different freeze-out scenarios are discussed such as single and double/flavor dependent freeze-out surfaces. Kinetic freeze-out parameters are obtained by doing hydrodynamic inspired blast wave fit to the transverse momentum distributions. The beam energy and centrality dependence of transverse energy per charged particle multiplicity are studied to address the constant energy per particle freeze-out criteria in heavy-ion collisions.

Charged particle multiplicity distributions in pp collisions at ISR energies

1977 ◽  
Vol 129 (3) ◽  
pp. 365-389 ◽  
Author(s):  
W. Thomé ◽  
K. Eggert ◽  
K. Giboni ◽  
H. Lisken ◽  
P. Darriulat ◽  
...  
Keyword(s):  
Charged Particle ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Pp Collisions ◽  
Multiplicity Distributions

scholarly journals Extending the Fully Bayesian Unfolding with Regularization Using a Combined Sampling Method

Symmetry ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2100
Author(s):  
Petr Baroň ◽  
Jiří Kvita
Keyword(s):  
Sampling Method ◽  
High Energy ◽  
Computational Time ◽  
Strength Parameter ◽  
Pp Collisions ◽  
Quark Pairs ◽  
Optimal Value ◽  
Particle Level ◽  
Fully Bayesian

Regularization extensions to the Fully Bayesian Unfolding are implemented and studied with an algorithm of combined sampling to find, in a reasonable computational time, an optimal value of the regularization strength parameter in order to obtain an unfolded result of a desired property, like smoothness. Three regularization conditions using the curvature, entropy and derivatives are applied, as a model example, to several simulated spectra of top-pair quark pairs that are produced in high energy pp collisions. The existence of a minimum of a χ2 between the unfolded and particle-level spectra is discussed, with recommendations on the checks and validity of the usage of the regularization feature in Fully Bayesian Unfolding (FBU).

scholarly journals Measurement of the Charged-Particle Multiplicity in pp Collisions at 102GeVc

1972 ◽  
Vol 29 (25) ◽  
pp. 1686-1688 ◽  
Author(s):  
J. W. Chapman ◽  
N. Green ◽  
B. P. Roe ◽  
A. A. Seidl ◽  
D. Sinclair ◽  
...  
Keyword(s):  
Charged Particle ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Pp Collisions

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 X-ray Variability of Blazars

2002 ◽  
Vol 19 (1) ◽  
pp. 49-54 ◽  
Author(s):  
Elena Pian
Keyword(s):  
Energy Range ◽  
High Energy ◽  
Space Missions ◽  
Present Review ◽  
Wide Energy Range ◽  
Spectral Variability ◽  
X Ray ◽  
Energy Emission ◽  
Wide Energy ◽  
High Energy Emission

AbstractCritical progress in our understanding of high energy emission from AGN has been determined in the last 10 years by X-ray monitoring campaigns with many space missions, notably ROSAT, ASCA, RXTE, BeppoSAX, and XMM, often in conjunction with observations at other frequencies. The emphasis of the present review is on recent findings about X-ray variability of blazars. Among AGN, these exhibit the largest amplitude variations of the X-ray emission, often well correlated with variations at higher energies (GeV and TeV radiation). The accurate sampling of the X-ray spectra over more than three decades in energy, made possible by the wide energy range of BeppoSAX, has also shown strong spectral variability in blazar active states, suggesting extreme electron energies and leading to the identification of a class of ‘extreme synchrotron’ sources.

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