scholarly journals Small collision systems: Theory overview on cold nuclear matter effects

2018 ◽  
Vol 171 ◽  
pp. 11001
Author(s):  
Néstor Armesto
Keyword(s):  
Nuclear Matter ◽  
Particle Production ◽  
Hadron Collider ◽  
Heavy Ion ◽  
Smooth Transition ◽  
Relativistic Heavy Ion Collider ◽  
Cold Nuclear Matter ◽  
Proton Proton ◽  
Small Systems ◽  
Matter Effects

Many observables measured at the Relativistic Heavy Ion Collider and the Large Hadron Collider show a smooth transition between proton-proton and protonnucleus collisions (small systems), and nucleus-nucleus collisions (large systems), when represented versus some variable like the multiplicity in the event. In this contribution I review some of the physics mechanisms, named cold nuclear matter effects, that may lead to a collective-like behaviour in small systems beyond the macroscopic description provided by relativistic hydrodynamics. I focus on the nuclear modification of parton densities, single inclusive particle production and correlations.

scholarly journals Comparing Two Different Initial Conditions AAMQS and Quartic Action in Illustrating the Effect of Valence Color Charges in High-EnergypACollisions at Forward Rapidity

2013 ◽  
Vol 2013 ◽  
pp. 1-14
Author(s):  
Ye-Yin Zhao ◽  
Ya-Hui Chen ◽  
Ya-Qin Gao ◽  
Fu-Hu Liu
Keyword(s):  
Particle Production ◽  
Initial Conditions ◽  
Hadron Collider ◽  
Heavy Ion ◽  
High Energy ◽  
Color Glass ◽  
Forward Rapidity ◽  
Relativistic Heavy Ion Collider ◽  
Proton Proton ◽  
Running Coupling

The inclusive particle productions in proton-proton (pp) and deuton-gold (d+Au) collisions at forward rapidity at the Relativistic Heavy Ion Collider (RHIC) energy are studied in the framework of the color glass condensate (CGC) theory by using two different initial conditions: AAMQS (Albacete-Armesto-Milhano-Quiroga-Salgado) and quartic action. Then, the results obtained by the two different initial conditions in illustrating the effect of valence color charges in high-energy proton-nucleus (pA) collisions at forward energy are compared. Meanwhile, the inclusive particle productions inpAcollisions at forward rapidity at the Large Hadron Collider (LHC) energies are predicted. The main dynamical input in our calculations is the use of solutions of the running coupling Balitsky-Kovchegov equation tested in electron-proton (ep) collision data. Particle production is computed via the hybrid formalisms to obtain spectra and yields. These baseline predictions are useful for testing the current understanding of the dynamics of very strong color fields against the upcoming LHC data.

Are the collective phenomena a universal feature of the hadronic matter created in p–p, p–A and A–A colliding systems?

2016 ◽  
Vol 25 (07) ◽  
pp. 1642007
Author(s):  
Eleazar Cuautle Flores
Keyword(s):  
Hadron Collider ◽  
Short Review ◽  
Heavy Ion ◽  
Hadronic Matter ◽  
Collective Phenomena ◽  
Relativistic Heavy Ion Collider ◽  
Proton Proton ◽  
Small Systems ◽  
Ion Collisions ◽  
Theoretical Side

Collective phenomena in ion–ion collisions are well-known, but the research in small systems, like proton–proton and proton-lead, is starting both from the experimental and theoretical side. In this paper, we present a short review of the most important observables related to flow, as well as phenomenological results to explain the Relativistic Heavy Ion Collider and Large Hadron Collider results. Different variables and their relations to collectivity in small systems are discussed.

scholarly journals Quarkonium Production Measurements with the ALICE Detector at the LHC

2019 ◽  
Vol 64 (7) ◽  
pp. 566
Author(s):  
F. Fionda
Keyword(s):  
Nuclear Matter ◽  
Decay Channel ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Pp Collisions ◽  
Cold Nuclear Matter ◽  
Proton Proton ◽  
Matter Effects ◽  
Ion Collisions ◽  
Quarkonium Production

In (ultra-)relativistic heavy-ion collisions, the strongly interactingmatter is predicted to undergo a phase transition into a plasma of deconfinedquarks and gluons (QGP) and quarkonia probe different aspects of this medium.However, the medium modification of quarkonium production includes also the contribution of cold nuclear matter effects (CNM), such as shadowing or nuclear break-up in addition to QGP effects. Proton--nucleus collisions, where no QGP is expected, are used to measure cold nuclear matter effects on quarkonium production. Vacuum production of quarkonia is modelled in proton--proton (pp) collisions, which are used as reference for both heavy-ion and proton--nucleus collisions. Besides serving as reference, results in pp collisions represent a benchmark test of QCD based models in both perturbative and non-perturbative regimes. The ALICE detector has unique capabilities at the LHC for measuring quarkonia down to zero transverse momentum. Measurements are carried out at both central and forward rapidity, in the dielectron and dimuon decay channel, respectively. In this contribution the latest quarkonium measurements for various energies and colliding systems, performed by the ALICE Collaboration during the LHC Run-2 period, will be discussed.

scholarly journals Small System Collectivity in Relativistic Hadronic and Nuclear Collisions

2018 ◽  
Vol 68 (1) ◽  
pp. 211-235 ◽  
Author(s):  
James L. Nagle ◽  
William A. Zajc
Keyword(s):  
Large Hadron Collider ◽  
Nuclear Matter ◽  
Hadron Collider ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collider ◽  
Small System ◽  
Nuclear Collisions ◽  
Ion Collisions ◽  
Bulk Motion ◽  
Inviscid Hydrodynamics

The bulk motion of nuclear matter at the ultrahigh temperatures created in heavy ion collisions at the Relativistic Heavy Ion Collider and the Large Hadron Collider is well described in terms of nearly inviscid hydrodynamics, thereby establishing this system of quarks and gluons as the most perfect fluid in nature. A revolution in the field is under way, spearheaded by the discovery of similar collective, fluid-like phenomena in much smaller systems including p+ p, p+ A, d+Au, and3He+Au collisions. We review these exciting new observations and their profound implications for hydrodynamic descriptions of small and/or out-of-equilibrium systems.

scholarly journals Comparing Multicomponent Erlang Distribution and Lévy Distribution of Particle Transverse Momentums

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Hua-Rong Wei ◽  
Ya-Hui Chen ◽  
Li-Na Gao ◽  
Fu-Hu Liu
Keyword(s):  
Hadron Collider ◽  
Center Of Mass ◽  
Heavy Ion ◽  
Erlang Distribution ◽  
Relativistic Heavy Ion Collider ◽  
Final State ◽  
Heavy Particles ◽  
Proton Proton ◽  
Lévy Distribution ◽  
Levy Distribution

The transverse momentum spectrums of final-state products produced in nucleus-nucleus and proton-proton collisions at different center-of-mass energies are analyzed by using a multicomponent Erlang distribution and the Lévy distribution. The results calculated by the two models are found in most cases to be in agreement with experimental data from the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). The multicomponent Erlang distribution that resulted from a multisource thermal model seems to give a better description as compared with the Lévy distribution. The temperature parameters of interacting system corresponding to different types of final-state products are obtained. Light particles correspond to a low temperature emission, and heavy particles correspond to a high temperature emission. Extracted temperature from central collisions is higher than that from peripheral collisions.

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