scholarly journals Transverse Momentum, Centrality, and Participant Nucleon Number Dependence of Elliptic Flow

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Bao-Chun Li ◽  
Yuan-Yuan Fu ◽  
Li-Li Wang ◽  
Fu-Hu Liu
Keyword(s):  
Transverse Momentum ◽  
Elliptic Flow ◽  
Nucleon Number ◽  
Azimuthal Asymmetries ◽  
Spectator Model ◽  
Overlap Region

In the combined framework of a multisource and participant-spectator model, we study the elliptic flow as a function of transverse momentum and number of participating nucleons insNN=200 GeV Au-Au andsNN=2.76 TeV Pb-Pb collisions and argue that the geometry of the initial overlap region in the collisions determines the experimentally measured azimuthal asymmetries. Our results are approximately in agreement with the data from PHENIX and ALICE collaborations.

scholarly journals Colour unwound - disentangling colours for azimuthal asymmetries in Drell-Yan scattering

2017 ◽  
Vol 3 (6) ◽  
Author(s):  
Daniël Boer ◽  
Tom van Daal ◽  
Jonathan Gaunt ◽  
Tomas Kasemets ◽  
Piet Mulders
Keyword(s):  
Transverse Momentum ◽  
Cross Section ◽  
Distribution Functions ◽  
Transverse Momentum Dependent ◽  
Gluon Vertex ◽  
Gluon Exchange ◽  
Azimuthal Asymmetries ◽  
The Given ◽  
Spectator Model

It has been suggested that a colour-entanglement effect exists in the Drell-Yan cross section for the ‘double T-odd’ contributions at low transverse momentum \bm{Q_\st}, rendering the colour structure different from that predicted by the usual factorisation formula . These T-odd contributions can come from the Boer-Mulders or Sivers transverse momentum dependent distribution functions. The different colour structure should be visible already at the lowest possible order that gives a contribution to the double Boer-Mulders (dBM) or double Sivers (dS) effect, that is at the level of two gluon exchanges. To discriminate between the different predictions, we compute the leading-power contribution to the low-\bm{Q_\st} dBM cross section at the two-gluon exchange order in the context of a spectator model. The computation is performed using a method of regions analysis with Collins subtraction terms implemented. The results conform with the predictions of the factorisation formula. In the cancellation of the colour entanglement, diagrams containing the three-gluon vertex are essential. Furthermore, the Glauber region turns out to play an important role – in fact, it is possible to assign the full contribution to the dBM cross section at the given order to the region in which the two gluons have Glauber scaling. A similar disentanglement of colour is found for the dS effect.

Color Entanglement in Hadronic Processes for Transverse Momentum Dependent Parton Distribution Functions

2015 ◽  
Vol 37 ◽  
pp. 1560022
Author(s):  
M. G. A. Buffing ◽  
P. J. Mulders
Keyword(s):  
Transverse Momentum ◽  
Parton Distribution ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Initial State ◽  
Color Flow ◽  
Transverse Momentum Dependent ◽  
Gauge Link ◽  
Azimuthal Asymmetries ◽  
Different Parts

In the description of protons, we go beyond the ordinary collinear parton distribution functions (PDFs), by including transverse momentum dependent PDFs (TMDs). As such, we become sensitive to polarization modes of the partons and protons that one cannot probe without accounting for transverse momenta of partons, in particular when looking at azimuthal asymmetries. Hadronic processes require the inclusion of gluon contributions forming the gauge links, which are path-ordered exponentials tracing the color flow. In processes with two hadrons in the initial state, such as Drell-Yan (DY), the gauge links from different parts of the process get entangled. We show that in color disentangling this gauge link structure, one becomes sensitive to this color flow. After disentanglement, particular combinations of TMDs will require a different numerical color factor than one naively might have expected. Such color factors will even play a role for azimuthal asymmetries in the simplest hadronic processes such as DY.

scholarly journals Effect of in-medium mass-shift on transverse-momentum spectrum and elliptic anisotropy of ϕ meson

2020 ◽  
Vol 29 (07) ◽  
pp. 2050047
Author(s):  
Yong Zhang ◽  
Jing Yang ◽  
Weihua Wu
Keyword(s):  
Transverse Momentum ◽  
Collision Energy ◽  
Elliptic Flow ◽  
Momentum Spectrum ◽  
Mass Shift ◽  
Large Momentum ◽  
Transverse Momentum Spectrum ◽  
Medium Mass ◽  
Different Sources ◽  
Momentum Region

We study the effect of in-medium mass-shift on transverse-momentum spectrum and elliptic anisotropy of [Formula: see text] meson. It is found that the mass-shift enhances the [Formula: see text] yields and suppresses the elliptic flow [Formula: see text] in large momentum region, and the effects increase with the increasing mass-shift. The effects are various for different sources and decrease with the increasing collision energy. We further study the effects for parts of all [Formula: see text] meson with mass-shift, and the effects decrease with the decreasing probability of [Formula: see text] meson with mass-shift. A possible method to detect the mass-shift of [Formula: see text] meson via transverse-momentum spectrum and [Formula: see text] is proposed.

PION ELLIPTIC FLOW AND HBT INTERFEROMETRY IN A GRANULAR QUARK-GLUON PLASMA DROPLET MODEL

2007 ◽  
Vol 16 (07n08) ◽  
pp. 1832-1838
Author(s):  
WEI-NING ZHANG ◽  
YAN-YU REN ◽  
CHEUK-YIN WONG
Keyword(s):  
Transverse Momentum ◽  
Velocity Distribution ◽  
Quark Gluon Plasma ◽  
Elliptic Flow ◽  
Gluon Plasma ◽  
Droplet Model ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
Hbt Interferometry

We use a model of quark-gluon plasma granular droplets that evolve hydrodynamically to investigate pion elliptic flow and Hanbury–Brown–Twiss interferometry. We find that the data of pion transverse momentum spectra, elliptic flows, and HBT radii in [Formula: see text] Au + Au collisions at RHIC can be described well by an expanding source of granular droplets with an anisotropic velocity distribution.

scholarly journals Weighted azimuthal asymmetries in a diquark spectator model

2010 ◽  
Vol 45 (3) ◽  
pp. 373-388 ◽  
Author(s):  
A. Bacchetta ◽  
M. Radici ◽  
F. Conti ◽  
M. Guagnelli
Keyword(s):  
Azimuthal Asymmetries ◽  
Spectator Model

scholarly journals On Particle Production in Lead-Gold Collision and Azimuthal Anisotropy at Top SPS Energy

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Bao-Chun Li ◽  
Zhao Zhang
Keyword(s):  
Transverse Momentum ◽  
Thermal Model ◽  
Particle Production ◽  
Elliptic Flow ◽  
High Energy ◽  
Azimuthal Anisotropy ◽  
Evolution Process ◽  
High Energy Collisions

In a multisource thermal model, we analyze the dependence of elliptic flowv2on the transverse momentumPT. The model results are compared with the data ofπ-,KS0,p, andΛmeasured in Pb + Au collisions at top SPS energy, 17.3 GeV. It is found that the azimuthal anisotropy in the evolution process of high-energy collisions is correlated highly to the number of participant nucleons.

scholarly journals Effect of non-eikonal corrections on azimuthal asymmetries in the color glass condensate

2019 ◽  
Vol 79 (9) ◽  
Author(s):  
Pedro Agostini ◽  
Tolga Altinoluk ◽  
Néstor Armesto
Keyword(s):  
Transverse Momentum ◽  
Large Hadron Collider ◽  
Collision Energy ◽  
Hadron Collider ◽  
Heavy Ion ◽  
Color Glass ◽  
Model Parameters ◽  
Color Glass Condensate ◽  
Relativistic Heavy Ion Collider ◽  
Azimuthal Asymmetries

Abstract We analyse the azimuthal structure of two gluon correlations in the color glass condensate including those effects that result from relaxing the shockwave approximation for the target. Working in the Glasma graph approach suitable for collisions between dilute systems, we compute numerically the azimuthal distributions and show that both even and odd harmonics appear. We study their dependence on model parameters, energy of the collision, pseudorapidity and transverse momentum of the produced particles, and length of the target. While the contribution from non-eikonal corrections vanishes with increasing collision energy and becomes negligible at the energies of the Large Hadron Collider, it is found to be sizeable up to top energies at the Relativistic Heavy Ion Collider.

scholarly journals Investigation of the Elliptic Flow Fluctuations of the Identified Particles Using the a Multi-Phase Transport Model

Universe ◽  
2020 ◽  
Vol 6 (9) ◽  
pp. 146
Author(s):  
Niseem Magdy ◽  
Xu Sun ◽  
Zhenyu Ye ◽  
Olga Evdokimov ◽  
Roy Lacey
Keyword(s):  
Transverse Momentum ◽  
Transport Model ◽  
Elliptic Flow ◽  
Momentum Dependence ◽  
Event Plane ◽  
First Order ◽  
Flow Fluctuations ◽  
Multi Phase ◽  
Phase Transport ◽  
Participant Plane

A Multi-Phase Transport (AMPT) model is used to study the elliptic flow fluctuations of identified particles using participant and spectator event planes. The elliptic flow measured using the first order spectator event plane is expected to give the elliptic flow relative to the true reaction plane which suppresses the flow fluctuations. However, the elliptic flow measured using the second-order participant plane is expected to capture the elliptic flow fluctuations. Our study shows that the first order spectator event plane could be used to study the elliptic flow fluctuations of the identified particles in the AMPT model. The elliptic flow fluctuations magnitude shows weak particle species dependence and transverse momentum dependence. Such observation will have important implications for understanding the source of the elliptic flow fluctuations.

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