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 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.

scholarly journals Collider searches for nonperturbative low-scale gravity states

2015 ◽  
Vol 30 (34) ◽  
pp. 1530061 ◽  
Author(s):  
Douglas M. Gingrich
Keyword(s):  
Large Hadron Collider ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Mass Energy ◽  
Personal View ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
8 Tev

The possibility of producing nonperturbative low-scale gravity states in collider experiments was first discussed in about 1998. The ATLAS and CMS experiments have searched for nonperturbative low-scale gravity states using the Large Hadron Collider with a proton–proton center-of-mass energy of 8 TeV. These experiments have now seriously confronted the possibility of producing nonperturbative low-scale gravity states which were proposed over 17 years ago. I will summarize the results of the searches, give a personal view of what they mean, and make some predictions for 13 TeV center-of-mass energy. I will also discuss early ATLAS 13 TeV center-of-mass energy results.

scholarly journals Hadron Spectra Parameters within the Non-Extensive Approach

Universe ◽  
2019 ◽  
Vol 5 (5) ◽  
pp. 122 ◽  
Author(s):  
Keming Shen ◽  
Gergely Gábor Barnaföldi ◽  
Tamás Sándor Biró
Keyword(s):  
High Energy Physics ◽  
Center Of Mass ◽  
Heavy Ion ◽  
High Energy ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Ion Collisions ◽  
Hadron Spectra ◽  
Hadron Mass ◽  
Energy Scaling

We investigate how the non-extensive approach works in high-energy physics. Transverse momentum ( p T ) spectra of several hadrons are fitted by various non-extensive momentum distributions and by the Boltzmann–Gibbs statistics. It is shown that some non-extensive distributions can be transferred one into another. We find explicit hadron mass and center-of-mass energy scaling both in the temperature and in the non-extensive parameter, q, in proton–proton and heavy-ion collisions. We find that the temperature depends linearly, but the Tsallis q follows a logarithmic dependence on the collision energy in proton–proton collisions. In the nucleus–nucleus collisions, on the other hand, T and q correlate linearly, as was predicted in our previous work.

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 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 TOP AND HIGGS PHYSICS AT THE HADRON COLLIDERS

2013 ◽  
Vol 28 (26) ◽  
pp. 1330038 ◽  
Author(s):  
SHABNAM JABEEN
Keyword(s):  
Top Quark ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Charge Asymmetry ◽  
Mass Energy ◽  
Top Quark Mass ◽  
Proton Antiproton ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Single Top

This review summarizes the recent results for top quark and Higgs boson measurements from experiments at Tevatron, a proton–antiproton collider at a center-of-mass energy of [Formula: see text], and the Large Hadron Collider, a proton–proton collider at a center-of-mass energy of [Formula: see text]. These results include the discovery of a Higgs-like boson and measurement of its various properties, and measurements in the top quark sector, e.g. top quark mass, spin, charge asymmetry and production of single top quark.

scholarly journals tt̄H Coupling Measurement with the ATLAS Detector at the LHC

2018 ◽  
Vol 182 ◽  
pp. 02052
Author(s):  
Asma Hadef
Keyword(s):  
Higgs Boson ◽  
Cross Sections ◽  
Top Quark ◽  
High Energy Physics ◽  
Center Of Mass ◽  
High Energy ◽  
New Physics ◽  
Decay Modes ◽  
Center Of Mass Energy ◽  
Higgs Decay

The Higgs boson was discovered on the 4th of July 2012 with a mass around 125 GeV by ATLAS and CMS experiments at LHC. Determining the Higgs properties (production and decay modes, couplings,...) is an important part of the high-energy physics programme in this decade. A search for the Higgs boson production in association with a top quark pair (tt̄H) at ATLAS [1] is summarized in this paper at an unexplored center-of-mass energy of 13 TeV, which could allow a first direct measurement of the top quark Yukawa coupling and could reveal new physics. The tt̄H analysis in ATLAS is divided into 3 channels according to the Higgs decay modes: H → Hadrons, H → Leptons and H → Photons. The best-fit value of the ratio of observed and Standard Model cross sections of tt̄H production process, using 2015-2016 data and combining all tt̄H final states, is 1:8±0:7, corresponds to 2:8σ (1:8σ) observed (expected) significance.

scholarly journals Event Patterns Extracted from Transverse Momentum and Rapidity Spectra ofZBosons and Quarkonium States Produced in pp and Pb-Pb Collisions at LHC

2016 ◽  
Vol 2016 ◽  
pp. 1-19 ◽  
Author(s):  
Ya-Hui Chen ◽  
Fu-Hu Liu ◽  
Roy A. Lacey
Keyword(s):  
Transverse Momentum ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Three Dimensional ◽  
Erlang Distribution ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Two Component ◽  
Scatter Plots ◽  
Parameter Values

Transverse momentum (pT) and rapidity (y) spectra ofZbosons and quarkonium states (some charmoniumcc¯mesons such asJ/ψandψ(2S)and some bottomoniumbb¯mesons such asΥ(1S),Υ(2S), andΥ(3S)) produced in proton-proton (pp) and lead-lead (Pb-Pb) collisions at the large hadron collider (LHC) are uniformly described by a hybrid model of two-component Erlang distribution forpTspectrum and two-component Gaussian distribution foryspectrum. The former distribution results from a multisource thermal model, and the latter one results from the revised Landau hydrodynamic model. The modelling results are in agreement with the experimental data measured in pp collisions at center-of-mass energiess=2.76and 7 TeV and in Pb-Pb collisions at center-of-mass energy per nucleon pairsNN=2.76 TeV. Based on the parameter values extracted frompTandyspectra, the event patterns (particle scatter plots) in two-dimensionalpT-yspace and in three-dimensional velocity space are obtained.

scholarly journals Porting HEP Parameterized Calorimeter Simulation Code to GPUs

2021 ◽  
Vol 4 ◽  
Author(s):  
Zhihua Dong ◽  
Heather Gray ◽  
Charles Leggett ◽  
Meifeng Lin ◽  
Vincent R. Pascuzzi ◽  
...  
Keyword(s):  
Data Analysis ◽  
High Energy Physics ◽  
Hadron Collider ◽  
High Energy ◽  
Simulation Code ◽  
Proton Proton ◽  
Proton Collisions ◽  
Data Rates ◽  
The Many ◽  
Proton Proton Collisions

The High Energy Physics (HEP) experiments, such as those at the Large Hadron Collider (LHC), traditionally consume large amounts of CPU cycles for detector simulations and data analysis, but rarely use compute accelerators such as GPUs. As the LHC is upgraded to allow for higher luminosity, resulting in much higher data rates, purely relying on CPUs may not provide enough computing power to support the simulation and data analysis needs. As a proof of concept, we investigate the feasibility of porting a HEP parameterized calorimeter simulation code to GPUs. We have chosen to use FastCaloSim, the ATLAS fast parametrized calorimeter simulation. While FastCaloSim is sufficiently fast such that it does not impose a bottleneck in detector simulations overall, significant speed-ups in the processing of large samples can be achieved from GPU parallelization at both the particle (intra-event) and event levels; this is especially beneficial in conditions expected at the high-luminosity LHC, where extremely high per-event particle multiplicities will result from the many simultaneous proton-proton collisions. We report our experience with porting FastCaloSim to NVIDIA GPUs using CUDA. A preliminary Kokkos implementation of FastCaloSim for portability to other parallel architectures is also described.

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