scholarly journals Pseudorapidity distributions of charged particles as a function of mid- and forward rapidity multiplicities in pp collisions at $$\sqrt{s}$$ = 5.02, 7 and 13 TeV

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
◽  
S. Acharya ◽  
D. Adamová ◽  
A. Adler ◽  
J. Adolfsson ◽  
...  
Keyword(s):  
Charged Particle ◽  
Particle Production ◽  
Charged Particles ◽  
Detailed Comparison ◽  
Centre Of Mass ◽  
Forward Rapidity ◽  
Pp Collisions ◽  
Proton Proton ◽  
Pseudorapidity Distributions ◽  
Pseudorapidity Density

AbstractThe multiplicity dependence of the pseudorapidity density of charged particles in proton–proton (pp) collisions at centre-of-mass energies $$\sqrt{s}~=~5.02$$ s = 5.02 , 7 and 13 TeV measured by ALICE is reported. The analysis relies on track segments measured in the midrapidity range ($$|\eta | < 1.5$$ | η | < 1.5 ). Results are presented for inelastic events having at least one charged particle produced in the pseudorapidity interval $$|\eta |<1$$ | η | < 1 . The multiplicity dependence of the pseudorapidity density of charged particles is measured with mid- and forward rapidity multiplicity estimators, the latter being less affected by autocorrelations. A detailed comparison with predictions from the PYTHIA 8 and EPOS LHC event generators is also presented. The results can be used to constrain models for particle production as a function of multiplicity in pp collisions.

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.

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 RENORMALIZATION GROUP EVOLUTION OF MULTI-GLUON CORRELATORS IN HIGH ENERGY QCD

2012 ◽  
Vol 20 ◽  
pp. 214-221
Author(s):  
JAMAL JALILIAN-MARIAN
Keyword(s):  
Particle Production ◽  
High Energy ◽  
Forward Rapidity ◽  
Proton Proton ◽  
Proton Collisions ◽  
Angular Correlations ◽  
Energy Proton ◽  
Group Evolution ◽  
Proton Proton Collisions ◽  
Made In

Forward rapidity di-hadron azimuthal angular correlations in high energy proton-nucleus and proton-proton collisions are sensitive to quadrupoles; traceless correlator of 4 Wilson lines whereas single inclusive particle production iNVOLVES only dipoles, traceless correlator of 2 Wilson lines. We discuss the progress made in understanding the energy (rapidity) evolution of the quadrupole as well as its various limits.

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.

Charged particle production in proton-proton inclusive reactions at very high energies

1974 ◽  
Vol 79 (2) ◽  
pp. 189-258 ◽  
Author(s):  
P. Capiluppi ◽  
G. Giacomelli ◽  
A.M. Rossi ◽  
G. Vannini ◽  
A. Bertin ◽  
...  
Keyword(s):  
Charged Particle ◽  
Particle Production ◽  
Proton Proton ◽  
High Energies ◽  
Charged Particle Production ◽  
Very High

scholarly journals CHARGED PARTICLES PRODUCED IN QUARK AND GLUON JETS IN PROTON-PROTON COLLISIONS

2011 ◽  
Vol 20 (07) ◽  
pp. 1583-1587
Author(s):  
SONA POCHYBOVA
Keyword(s):  
Particle Production ◽  
Current Knowledge ◽  
Charged Particles ◽  
Minimum Bias ◽  
Proton Proton ◽  
Proton Collisions ◽  
Hadron Spectra ◽  
Gluon Jets ◽  
Proton Proton Collisions ◽  
Existing Data

The study of particle production inside jets makes it possible to address the fragmentation properties of the leading parton depending on its flavour. We study the spectra of K, p and π production in minimum bias (inelastic, non- diffractive), two- and three-jet events at RHIC, Tevatron and LHC energies. To address the properties of quark and gluon jets, different production channels are investigated. We present MC estimate for the contribution of quark and gluon jets to individual hadron spectra, that can be compared to experimental results and test our current knowledge of the physics behind particle production inside jets. Where possible, we cross-check our results with existing data and further extend the study to higher energies.

scholarly journals Measurement of the forward charged-particle pseudorapidity density in pp collisions at √s = 7 TeV with the TOTEM experiment

2012 ◽  
Vol 98 (3) ◽  
pp. 31002 ◽  
Author(s):  
◽  
G. Antchev ◽  
P. Aspell ◽  
I. Atanassov ◽  
V. Avati ◽  
...  
Keyword(s):  
Charged Particle ◽  
Pp Collisions ◽  
Pseudorapidity Density

scholarly journals Production of pions, kaons, (anti-)protons and $$\phi $$ mesons in Xe–Xe collisions at $$\sqrt{s_{\mathrm{NN}}}$$ = 5.44 TeV

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
◽  
S. Acharya ◽  
D. Adamová ◽  
A. Adler ◽  
J. Adolfsson ◽  
...  
Keyword(s):  
Charged Particle ◽  
Particle Production ◽  
Radial Flow ◽  
Detailed Comparison ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Final State ◽  
Phi Mesons ◽  
Particle Ratios ◽  
State Multiplicity

AbstractThe first measurement of the production of pions, kaons, (anti-)protons and $$\phi $$ ϕ mesons at midrapidity in Xe–Xe collisions at $$\sqrt{s_{\mathrm{NN}}} = 5.44~\text {TeV}$$ s NN = 5.44 TeV is presented. Transverse momentum ($$p_{\mathrm{T}}$$ p T ) spectra and $$p_{\mathrm{T}}$$ p T -integrated yields are extracted in several centrality intervals bridging from p–Pb to mid-central Pb–Pb collisions in terms of final-state multiplicity. The study of Xe–Xe and Pb–Pb collisions allows systems at similar charged-particle multiplicities but with different initial geometrical eccentricities to be investigated. A detailed comparison of the spectral shapes in the two systems reveals an opposite behaviour for radial and elliptic flow. In particular, this study shows that the radial flow does not depend on the colliding system when compared at similar charged-particle multiplicity. In terms of hadron chemistry, the previously observed smooth evolution of particle ratios with multiplicity from small to large collision systems is also found to hold in Xe–Xe. In addition, our results confirm that two remarkable features of particle production at LHC energies are also valid in the collision of medium-sized nuclei: the lower proton-to-pion ratio with respect to the thermal model expectations and the increase of the $$\phi $$ ϕ -to-pion ratio with increasing final-state multiplicity.

Pseudorapidity Distributions of Charged Particles Produced in pp Collisions at the CERN LHC Energies

2011 ◽  
Vol 59 (5) ◽  
pp. 3138-3140 ◽  
Author(s):  
Jian-Xin Sun ◽  
Cai-Xing Tian ◽  
Er-Qin Wang ◽  
Fu-Hu Liu
Keyword(s):  
Charged Particles ◽  
Pp Collisions ◽  
Pseudorapidity Distributions
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