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Centrality dependence of identified particles in relativistic heavy ion collisions at sqrt(s)= 7.7-62.4 GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.C 93 (2016) 014907, 2016.
Inspire Record 1395151 DOI 10.17182/hepdata.71527

Elliptic flow (v_2) values for identified particles at midrapidity in Au + Au collisions measured by the STAR experiment in the Beam Energy Scan at the Relativistic Heavy Ion Collider at sqrt{s_{NN}}= 7.7--62.4 GeV are presented for three centrality classes. The centrality dependence and the data at sqrt{s_{NN}}= 14.5 GeV are new. Except at the lowest beam energies we observe a similar relative v_2 baryon-meson splitting for all centrality classes which is in agreement within 15% with the number-of-constituent quark scaling. The larger v_2 for most particles relative to antiparticles, already observed for minimum bias collisions, shows a clear centrality dependence, with the largest difference for the most central collisions. Also, the results are compared with A Multiphase Transport Model and fit with a Blast Wave model.

494 data tables
Table 1

No description provided.

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Table 3

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Centrality and transverse momentum dependence of elliptic flow of multi-strange hadrons and $\phi$ meson in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.Lett. 116 (2016) 062301, 2016.
Inspire Record 1383879 DOI 10.17182/hepdata.71571

We present high precision measurements of elliptic flow near midrapidity ($|y|<1.0$) for multi-strange hadrons and $\phi$ meson as a function of centrality and transverse momentum in Au+Au collisions at center of mass energy $\sqrt{s_{NN}}=$ 200 GeV. We observe that the transverse momentum dependence of $\phi$ and $\Omega$ $v_{2}$ is similar to that of $\pi$ and $p$, respectively, which may indicate that the heavier strange quark flows as strongly as the lighter up and down quarks. This observation constitutes a clear piece of evidence for the development of partonic collectivity in heavy-ion collisions at the top RHIC energy. Number of constituent quark scaling is found to hold within statistical uncertainty for both 0-30$\%$ and 30-80$\%$ collision centrality. There is an indication of the breakdown of previously observed mass ordering between $\phi$ and proton $v_{2}$ at low transverse momentum in the 0-30$\%$ centrality range, possibly indicating late hadronic interactions affecting the proton $v_{2}$.

0 data tables

Azimuthal anisotropy in U+U and Au+Au collisions at RHIC

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.Lett. 115 (2015) 222301, 2015.
Inspire Record 1373553 DOI 10.17182/hepdata.71502

Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, $v_2\{2\}$ and $v_2\{4\}$, for charged hadrons from U+U collisions at $\sqrt{s_{\rm NN}}$ = 193 GeV and Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 200 GeV. Nearly fully overlapping collisions are selected based on the amount of energy deposited by spectators in the STAR Zero Degree Calorimeters (ZDCs). Within this sample, the observed dependence of $v_2\{2\}$ on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in U+U collisions. An initial-state model with gluon saturation describes the slope of $v_2\{2\}$ as a function of multiplicity in central collisions better than one based on Glauber with a two-component multiplicity model.

20 data tables
Table 1

No description provided.

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Observation of charge asymmetry dependence of pion elliptic flow and the possible chiral magnetic wave in heavy-ion collisions

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.Lett. 114 (2015) 252302, 2015.
Inspire Record 1358666 DOI 10.17182/hepdata.72237

We present measurements of $\pi^-$ and $\pi^+$ elliptic flow, $v_2$, at midrapidity in Au+Au collisions at $\sqrt{s_{_{\rm NN}}} =$ 200, 62.4, 39, 27, 19.6, 11.5 and 7.7 GeV, as a function of event-by-event charge asymmetry, $A_{ch}$, based on data from the STAR experiment at RHIC. We find that $\pi^-$ ($\pi^+$) elliptic flow linearly increases (decreases) with charge asymmetry for most centrality bins at $\sqrt{s_{_{\rm NN}}} = \text{27 GeV}$ and higher. At $\sqrt{s_{_{\rm NN}}} = \text{200 GeV}$, the slope of the difference of $v_2$ between $\pi^-$ and $\pi^+$ as a function of $A_{ch}$ exhibits a centrality dependence, which is qualitatively similar to calculations that incorporate a chiral magnetic wave effect. Similar centrality dependence is also observed at lower energies.

0 data tables

Long-range pseudorapidity dihadron correlations in $d$+Au collisions at $\sqrt{s_{\rm NN}}=200$ GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Lett.B 747 (2015) 265-271, 2015.
Inspire Record 1346551 DOI 10.17182/hepdata.72303

Dihadron angular correlations in $d$+Au collisions at $\sqrt{s_{\rm NN}}=200$ GeV are reported as a function of the measured zero-degree calorimeter neutral energy and the forward charged hadron multiplicity in the Au-beam direction. A finite correlated yield is observed at large relative pseudorapidity ($\Delta\eta$) on the near side (i.e. relative azimuth $\Delta\phi\sim0$). This correlated yield as a function of $\Delta\eta$ appears to scale with the dominant, primarily jet-related, away-side ($\Delta\phi\sim\pi$) yield. The Fourier coefficients of the $\Delta\phi$ correlation, $V_{n}=\langle\cos n\Delta\phi\rangle$, have a strong $\Delta\eta$ dependence. In addition, it is found that $V_{1}$ is approximately inversely proportional to the mid-rapidity event multiplicity, while $V_{2}$ is independent of it with similar magnitude in the forward ($d$-going) and backward (Au-going) directions.

23 data tables
Table 1

Correlated dihadron yield, per radian per unit of pseudorapidity, as a function of $\Delta\phi$ for 1.2 < $|\Delta\eta|$ < 1.8 in d+Au collisions, for low ZDC-Au activity data. Both the trigger and associated particles have 1 < $p_T$ < 3 GeV/c.

Table 2

Correlated dihadron yield, per radian per unit of pseudorapidity, as a function of $\Delta\phi$ for 1.2 < $|\Delta\eta|$ < 1.8 in d+Au collisions, for high ZDC-Au activity data. Both the trigger and associated particles have 1 < $p_T$ < 3 GeV/c.

Table 3

Correlated dihadron yield, per radian per unit of pseudorapidity, as a function of $\Delta\phi$ for -4.5 < $\Delta\eta$ < -2 in d+Au collisions, for low ZDC-Au activity data. Both the trigger and associated particles have 1 < $p_T$ < 3 GeV/c.

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Measurement of flow harmonics with multi-particle cumulants in Pb+Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Eur.Phys.J.C 74 (2014) 3157, 2014.
Inspire Record 1311487 DOI 10.17182/hepdata.65771

ATLAS measurements of the azimuthal anisotropy in lead-lead collisions at $\sqrt{s_{NN}}=2.76$ TeV are shown using a dataset of approximately 7 $\mu$b$^{-1}$ collected at the LHC in 2010. The measurements are performed for charged particles with transverse momenta $0.5<p_T<20$ GeV and in the pseudorapidity range $|\eta|<2.5$. The anisotropy is characterized by the Fourier coefficients, $v_n$, of the charged-particle azimuthal angle distribution for n = 2-4. The Fourier coefficients are evaluated using multi-particle cumulants calculated with the generating function method. Results on the transverse momentum, pseudorapidity and centrality dependence of the $v_n$ coefficients are presented. The elliptic flow, $v_2$, is obtained from the two-, four-, six- and eight-particle cumulants while higher-order coefficients, $v_3$ and $v_4$, are determined with two- and four-particle cumulants. Flow harmonics $v_n$ measured with four-particle cumulants are significantly reduced compared to the measurement involving two-particle cumulants. A comparison to $v_n$ measurements obtained using different analysis methods and previously reported by the LHC experiments is also shown. Results of measurements of flow fluctuations evaluated with multi-particle cumulants are shown as a function of transverse momentum and the collision centrality. Models of the initial spatial geometry and its fluctuations fail to describe the flow fluctuations measurements.

220 data tables
Table 1

The second flow harmonic measured with the two-particle cumulants as a function of transverse momentum in centrality bin 0-2%.

Table 2

The second flow harmonic measured with the two-particle cumulants as a function of transverse momentum in centrality bin 2-5%.

Table 3

The second flow harmonic measured with the two-particle cumulants as a function of transverse momentum in centrality bin 5-10%.

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Measurement of the centrality and pseudorapidity dependence of the integrated elliptic flow in lead-lead collisions at sqrt(s_NN)=2.76 TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Eur.Phys.J.C 74 (2014) 2982, 2014.
Inspire Record 1296260 DOI 10.17182/hepdata.66180

The integrated elliptic flow of charged particles produced in Pb+Pb collisions at sqrt(s_NN)=2.76 TeV has been measured with the ATLAS detector using data collected at the Large Hadron Collider. The anisotropy parameter, v_2, was measured in the pseudorapidity range |eta| <= 2.5 with the event-plane method. In order to include tracks with very low transverse momentum pT, thus reducing the uncertainty in v_2 integrated over pT, a 1 mu b-1 data sample without a magnetic field in the tracking detectors is used. The centrality dependence of the integrated v_2 is compared to other measurements obtained with higher pT thresholds. A weak pseudorapidity dependence of the integrated elliptic flow is observed for central collisions, and a small decrease when moving away from mid-rapidity is observed only in peripheral collisions. The integrated v2 transformed to the rest frame of one of the colliding nuclei is compared to the lower-energy RHIC data.

38 data tables
Table 1

Monte Carlo evaluation of the tracklet reconstruction efficiency as a function of pseudorapidity for the 0-10% centraliry interval.

Table 2

Monte Carlo evaluation of the tracklet reconstruction efficiency as a function of pseudorapidity for the 40-50% centraliry interval.

Table 3

Monte Carlo evaluation of the tracklet reconstruction efficiency as a function of pseudorapidity for the 70-80% centraliry interval.

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D meson elliptic flow in non-central Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76TeV

The ALICE collaboration Abelev, B. ; Adam, J. ; Adamova, D. ; et al.
Phys.Rev.Lett. 111 (2013) 102301, 2013.
Inspire Record 1233087 DOI 10.17182/hepdata.61916

Azimuthally anisotropic distributions of D$^0$, D$^+$ and D$^{*+}$ mesons were studied in the central rapidity region ($|y|<0.8$) in Pb-Pb collisions at a centre-of-mass energy $\sqrt{s_{\rm NN}} = 2.76$ TeV per nucleon-nucleon collision, with the ALICE detector at the LHC. The second Fourier coefficient $v_2$ (commonly denoted elliptic flow) was measured in the centrality class 30-50% as a function of the D meson transverse momentum $p_{\rm T}$, in the range 2-16 GeV/$c$. The measured $v_2$ of D mesons is comparable in magnitude to that of light-flavour hadrons. It is positive in the range $2 < p_{\rm T} < 6$ GeV/$c$ with $5.7\sigma$ significance, based on the combination of statistical and systematic uncertainties.

4 data tables
Table 1

v2 vs. pt for D0. The first systematic (sys) error is that from the data analysis and the second is from the B feed-down subtraction, as explained in the paper.

Table 2

v2 vs. pt for D+. The first systematic (sys) error is that from the data analysis and the second is from the B feed-down subtraction, as explained in the paper.

Table 3

v2 vs. pt for D*+. The first systematic (sys) error is that from the data analysis and the second is from the B feed-down subtraction, as explained in the paper.

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Measurement of the distributions of event-by-event flow harmonics in lead--lead collisions at sqrt(s_NN)=2.76 TeV with the ATLAS detector at the LHC

The ATLAS collaboration Aad, Georges ; Abajyan, Tatevik ; Abbott, Brad ; et al.
JHEP 11 (2013) 183, 2013.
Inspire Record 1233359 DOI 10.17182/hepdata.62783

The distributions of event-by-event harmonic flow coefficients v_n for n=2-4 are measured in sqrt(s_NN)=2.76 TeV Pb+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using charged particles with transverse momentum pT> 0.5 GeV and in the pseudorapidity range |eta|<2.5 in a dataset of approximately 7 ub^-1 recorded in 2010. The shapes of the v_n distributions are described by a two-dimensional Gaussian function for the underlying flow vector in central collisions for v_2 and over most of the measured centrality range for v_3 and v_4. Significant deviations from this function are observed for v_2 in mid-central and peripheral collisions, and a small deviation is observed for v_3 in mid-central collisions. It is shown that the commonly used multi-particle cumulants are insensitive to the deviations for v_2. The v_n distributions are also measured independently for charged particles with 0.5<pT<1 GeV and pT>1 GeV. When these distributions are rescaled to the same mean values, the adjusted shapes are found to be nearly the same for these two pT ranges. The v_n distributions are compared with the eccentricity distributions from two models for the initial collision geometry: a Glauber model and a model that includes corrections to the initial geometry due to gluon saturation effects. Both models fail to describe the experimental data consistently over most of the measured centrality range.

201 data tables
Table 1

The relationship between centrality intervals and MEAN(Npart) estimated from the Glauber model.

Table 2

The MEAN(Npart) dependence of MEAN(V2) for three pT ranges together with the total systematic uncertainties.

Table 3

The MEAN(Npart) dependence of SIGMA(V2) for three pT ranges together with the total systematic uncertainties.

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J/Psi Elliptic Flow in Pb-Pb Collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV

The ALICE collaboration Abbas, Ehab ; Abelev, Betty ; Adam, Jaroslav ; et al.
Phys.Rev.Lett. 111 (2013) 162301, 2013.
Inspire Record 1225273 DOI 10.17182/hepdata.61768

We report on the first measurement of inclusive J/$\psi$ elliptic flow, $v_2$, in heavy-ion collisions at the LHC. The measurement is performed with the ALICE detector in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV in the rapidity range $2.5 < y < 4.0$. The dependence of the J/$\psi$ $v_2$ on the collision centrality and on the J/$\psi$ transverse momentum is studied in the range $0 < p_{\rm T} < 10$ GeV/$c$. For semi-central Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV, an indication of non-zero $v_2$ is observed with a maximum value of $v_2 = 0.116 \pm 0.046 {\rm (stat.)} \pm 0.029 {\rm (syst.)}$ for J/$\psi$ in the transverse momentum range $2 < p_{\rm T} < 4$ GeV/$c$. The elliptic flow measurement complements the previously reported ALICE results on the inclusive J/$\psi$ nuclear modification factor and favors the scenario of a significant fraction of J/$\psi$ production from charm quarks in a deconfined partonic phase.

0 data tables