ترغب بنشر مسار تعليمي؟ اضغط هنا

Observation of an energy-dependent difference in elliptic flow between particles and anti-particles in relativistic heavy ion collisions

175   0   0.0 ( 0 )
 نشر من قبل Alexander Schmah
 تاريخ النشر 2013
  مجال البحث
والبحث باللغة English




اسأل ChatGPT حول البحث

Elliptic flow ($v_{2}$) values for identified particles at mid-rapidity in Au+Au collisions, measured by the STAR experiment in the Beam Energy Scan at RHIC at $sqrt{s_{NN}}=$ 7.7--62.4 GeV, are presented. A beam-energy dependent difference of the values of $v_{2}$ between particles and corresponding anti-particles was observed. The difference increases with decreasing beam energy and is larger for baryons compared to mesons. This implies that, at lower energies, particles and anti-particles are not consistent with the universal number-of-constituent-quark (NCQ) scaling of $v_{2}$ that was observed at $sqrt{s_{NN}}=$ 200 GeV.

قيم البحث

اقرأ أيضاً

252 - B.Alver , B.B.Back , M.D.Baker 2007
We present the first measurements of the pseudorapidity distribution of primary charged particles in Cu+Cu collisions as a function of collision centrality and energy, sqrtsnn = 22.4, 62.4 and 200 GeV, over a wide range of pseudorapidity, using the P HOBOS detector. Making a global comparison of Cu+Cu and Au+Au results, we find that the total number of produced charged particles and the rough shape (height and width) of the pseudorapidity distributions are determined by the number of nucleon participants. More detailed studies reveal that a more precise matching of the shape of the Cu+Cu and Au+Au pseudorapidity distributions over the full range of pseudorapidity occurs for the same Npart/2A value rather than the same Npart value. In other words, it is the collision geometry rather than just the number of nucleon participants that drives the detailed shape of the pseudorapidity distribution and its centrality dependence at RHIC energies.
90 - Shusu Shi 2016
Strange hadrons, especially multi-strange hadrons are good probes for the early partonic stage of heavy ion collisions due to their small hadronic cross sections. In this paper, I give a brief review on the elliptic flow measurements of strange and m ulti-strange hadrons in relativistic heavy ion collisions at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC).
We study effects of eccentricity fluctuations on the elliptic flow coefficient v_2 at mid-rapidity in both Au+Au and Cu+Cu collisions at sqrt{s_NN}=200 GeV by using a hybrid model that combines ideal hydrodynamics for space-time evolution of the quar k gluon plasma phase and a hadronic transport model for the hadronic matter. For initial conditions in hydrodynamic simulations, both the Glauber model and the color glass condensate model are employed to demonstrate the effect of initial eccentricity fluctuations originating from the nucleon position inside a colliding nucleus. The effect of eccentricity fluctuations is modest in semicentral Au+Au collisions, but significantly enhances v_2 in Cu+Cu collisions.
103 - Shusu Shi 2012
We present measurement of elliptic flow, $v_2$, for charged and identified particles at midrapidity in Au+Au collisions at $sqrt{s_{NN}}$ = 7.7 - 39 GeV. We compare the inclusive charged hadron $v_2$ to those from transport model calculations, such a s UrQMD model, AMPT default model and AMPT string-melting model. We discuss the energy dependence of the difference in $v_2$ between particles and anti-particles. The $v_2$ of $phi$ meson is observed to be systematically lower than other particles in Au+Au collisions at $sqrt{s_{NN}}$ = 11.5 GeV.
At the early stage of heavy ion collisions, non-trivial topologies of the gauge fields can be created resulting in an imbalance of axial charge density and eventually separation of electric charges along the direction of the magnetic field produced i n such collisions. This process is called the chiral magnetic effect (CME). In this work we implement such a charge separation at the partonic level in AMPT for Au+Au collisions at $sqrt{s_{NN}}$ = 200 GeV to study its consequence on experimental observables. We present the effects on the pion elliptic flow ($v_2$) and the charged particle balance function (BF) for varying strengths of initial charge separation. We find that the shape of the balance function is sensitive to the increasing charge separation. $v_2$ of pion shows a strong decreasing trend at higher transverse momenta ($p_T$) with increasing charge separation. Charge balance functions show a peak at $Deltaphi sim 180 $ with charge separation implemented in the partonic level as expected for the parity violation. We have also calculated parity observable $gamma$ in the form of BFs moments. $gamma$ shows a decreasing trend with charge separation. It has a negative value for charge separation produced by flipping more than 30 $%$ of quarks in the parton level. We also notice that $<gamma>$ for the same charge correlation and the opposite charge correlation shows negative and positive values, respectively.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا