Energy dependence of $\pi^{\pm}$, $p$ and $\bar{p}$ transverse momentum spectrafor Au+Au collisions at $\sqrt{s_{\mathrm {NN}}}$~=~62.4 and 200 GeV

The STAR collaboration Abelev, B.I. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Lett.B 655 (2007) 104-113, 2007.
Inspire Record 747299 DOI 10.17182/hepdata.100592

We study the energy dependence of the transverse momentum (pT) spectra for charged pions, protons and anti-protons for Au+Au collisions at \sqrt{s_NN} = 62.4 and 200 GeV. Data are presented at mid-rapidity (|y| < 0.5) for 0.2 < pT < 12 GeV/c. In the intermediate pT region (2 < pT < 6 GeV/c), the nuclear modification factor is higher at 62.4 GeV than at 200 GeV, while at higher pT (pT >7 GeV/c) the modification is similar for both energies. The p/pi+ and pbar/pi- ratios for central collisions at \sqrt{s_NN} = 62.4 GeV peak at pT ~ 2 GeV/c. In the pT range where recombination is expected to dominate, the p/pi+ ratios at 62.4 GeV are larger than at 200 GeV, while the pbar/pi- ratios are smaller. For pT > 2 GeV/c, the pbar/pi- ratios at the two beam energies are independent of pT and centrality indicating that the dependence of the pbar/pi- ratio on pT does not change between 62.4 and 200 GeV. These findings challenge various models incorporating jet quenching and/or constituent quark coalescence.

5 data tables

Midrapidity (|y| < 0.5) transverse momentum spectra for pions, protons, anti-protons for various event centrality classes for Au+Au at sqrt(sNN) = 62.4 GeV. Also shown to study the energy dependence are the central 0-12% pion, proton, anti-proton spectra for Au+Au at sqrt(sNN) = 200 GeV.

The insets show pi−/pi+ ratios at sqrt(sNN) = 62.4 GeV and anti-proton/proton ratios at sqrt(sNN) = 62.4 (0-10%) and 200 GeV (0-12%).

The minimum bias data shown here were extracted from the figures by xyscan. Hence, the dataset is not full (especially in the lower pT range where it is hard to distinguish points), and the statistical errors shown here are an upper limit of the statistical uncertainty based on the marker sizes.

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Mass, quark-number, and sqrt s(NN) dependence of the second and fourth flow harmonics in ultra-relativistic nucleus-nucleus collisions

The STAR collaboration Abelev, B.I. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.C 75 (2007) 054906, 2007.
Inspire Record 741917 DOI 10.17182/hepdata.104927

We present STAR measurements of the azimuthal anisotropy parameter $v_2$ for pions, kaons, protons, $\Lambda$, $\bar{\Lambda}$, $\Xi+\bar{\Xi}$, and $\Omega + \bar{\Omega}$, along with $v_4$ for pions, kaons, protons, and $\Lambda + \bar{\Lambda}$ at mid-rapidity for Au+Au collisions at $\sqrt{s_{_{NN}}}=62.4$ and 200 GeV. The $v_2(p_T)$ values for all hadron species at 62.4 GeV are similar to those observed in 130 and 200 GeV collisions. For observed kinematic ranges, $v_2$ values at 62.4, 130, and 200 GeV are as little as 10%--15% larger than those in Pb+Pb collisions at $\sqrt{s_{_{NN}}}=17.3$ GeV. At intermediate transverse momentum ($p_T$ from 1.5--5 GeV/c), the 62.4 GeV $v_2(p_T)$ and $v_4(p_T)$ values are consistent with the quark-number scaling first observed at 200 GeV. A four-particle cumulant analysis is used to assess the non-flow contributions to pions and protons and some indications are found for a smaller non-flow contribution to protons than pions. Baryon $v_2$ is larger than anti-baryon $v_2$ at 62.4 and 200 GeV perhaps indicating either that the initial spatial net-baryon distribution is anisotropic, that the mechanism leading to transport of baryon number from beam- to mid-rapidity enhances $v_2$, or that anti-baryon and baryon annihilation is larger in the in-plane direction.

106 data tables

Minimum-bias (0–80% of the collision cross section) v2(pT ) for identified hadrons at |η| < 1 from Au+Au collisions at √sNN = 62.4 GeV. To facilitate comparisons between panels, v2 values for inclusive charged hadrons are displayed in each panel. The error bars on the data points represent statistical uncertainties. Systematic uncertainties for the identified particles are shown as shaded bands around v2 = 0.

Minimum-bias (0–80% of the collision cross section) v2(pT ) for identified hadrons at |η| < 1 from Au+Au collisions at √sNN = 62.4 GeV. To facilitate comparisons between panels, v2 values for inclusive charged hadrons are displayed in each panel. The error bars on the data points represent statistical uncertainties. Systematic uncertainties for the identified particles are shown as shaded bands around v2 = 0.

Minimum-bias (0–80% of the collision cross section) v2(pT ) for identified hadrons at |η| < 1 from Au+Au collisions at √sNN = 62.4 GeV. To facilitate comparisons between panels, v2 values for inclusive charged hadrons are displayed in each panel. The error bars on the data points represent statistical uncertainties. Systematic uncertainties for the identified particles are shown as shaded bands around v2 = 0.

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Rapidity and species dependence of particle production at large transverse momentum for d + Au collisions at s(NN)**(1/2) = 200-GeV.

The STAR collaboration Abelev, B.I. ; Adams, J. ; Aggarwal, M.M. ; et al.
Phys.Rev.C 76 (2007) 054903, 2007.
Inspire Record 726101 DOI 10.17182/hepdata.101349

We determine rapidity asymmetry in the production of charged pions, protons and anti-protons for large transverse momentum (pT) for d+Au collisions at \sqrt s_NN = 200 GeV. The identified hadrons are measured in the rapidity regions |y| < 0.5 and 0.5 < |y| < 1.0 for the pT range 2.5 < pT < 10 GeV/c. We observe significant rapidity asymmetry for charged pion and proton+anti-proton production in both rapidity regions. The asymmetry is larger for 0.5 < |y| < 1.0 than for |y|< 0.5 and is almost independent of particle type. The measurements are compared to various model predictions employing multiple scattering, energy loss, nuclear shadowing, saturation effects, and recombination, and also to a phenomenological parton model. We find that asymmetries are sensitive to model parameters and show model-preference. The rapidity dependence of \pi^{-}/\pi^{+} and \bar{p}/p ratios in peripheral d+Au and forward neutron-tagged events are used to study the contributions of valence quarks and gluons to particle production at high pT. The results are compared to calculations based on NLO pQCD and other measurements of quark fragmentation functions.

15 data tables

High transverse-momentum spectra ($p_{T} > 2.5$ GeV/c) of charged pions, protons, and antiprotons for the rapidity regions $|y| < 0.5$ (solid symbols) and $0.5 < |y| < 1.0$ (open symbols) for $d+Au$ collisions and various event centrality classes at $\sqrt{s_{NN}}=200$ GeV.

High transverse-momentum spectra ($p_{T} > 2.5$ GeV/c) of charged pions, protons, and antiprotons for the rapidity regions $|y| < 0.5$ (solid symbols) and $0.5 < |y| < 1.0$ (open symbols) for $d+Au$ collisions and various event centrality classes at $\sqrt{s_{NN}}=200$ GeV.

High transverse-momentum spectra ($p_{T} > 2.5$ GeV/c) of charged pions, protons, and antiprotons for the rapidity regions $|y| < 0.5$ (solid symbols) and $0.5 < |y| < 1.0$ (open symbols) for $d+Au$ collisions and various event centrality classes at $\sqrt{s_{NN}}=200$ GeV.

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Neutral kaon interferometry in Au + Au collisions at s(NN)**(1/2) = 200-GeV.

The STAR collaboration Abelev, B.I. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.C 74 (2006) 054902, 2006.
Inspire Record 723366 DOI 10.17182/hepdata.97123

We present the first statistically meaningful results from two-K0s interferometry in heavy-ion collisions. A model that takes the effect of the strong interaction into account has been used to fit the measured correlation function. The effects of single and coupled channel were explored. At the mean transverse mass m_T = 1.07 GeV, we obtain the values R = 4.09 +/- 0.46 (stat.) +/- 0.31 (sys) fm and lambda = 0.92 +/- 0.23 (stat) +/- 0.13 (sys), where R and lambda are the invariant radius and chaoticity parameters respectively. The results are qualitatively consistent with m_T systematics established with pions in a scenario characterized by a strong collective flow.

10 data tables

K0s invariant mass distribution

Signal to (Signal + Background) ratio for K0s decay length > 6 cm.

Mean KT distribution of K0s pairs

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Longitudinal double-spin asymmetry and cross section for inclusive jet production in polarized proton collisions at s**(1/2) = 200-GeV.

The STAR collaboration Abelev, B.I. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.Lett. 97 (2006) 252001, 2006.
Inspire Record 723509 DOI 10.17182/hepdata.104928

We report a measurement of the longitudinal double-spin asymmetry A_LL and the differential cross section for inclusive midrapidity jet production in polarized proton collisions at sqrt(s)=200 GeV. The cross section data cover transverse momenta 5 < pT < 50 GeV/c and agree with next-to-leading order perturbative QCD evaluations. The A_LL data cover 5 < pT < 17 GeV/c and disfavor at 98% C.L. maximal positive gluon polarization in the polarized nucleon.

3 data tables

(a) Inclusive differential cross section for p+p -> jet +X at sqrt(s) = 200 GeV versus jet pT for a jet cone radius of 0.4. The symbols show MB (open squares) and HT (filled circles) data from the years 2003 and 2004 combined. The horizontal bars indicate the ranges of the pT intervals. The curve shows a NLO calculation. (b) Comparison of theory and data. The band indicates the experimental systematic uncertainty. The upper (lower) dashed line indicates the relative change of the NLO calculation when it is evaluated at &mu = pT/2 (&mu = 2pT).

(a) Inclusive differential cross section for p+p -> jet +X at sqrt(s) = 200 GeV versus jet pT for a jet cone radius of 0.4. The symbols show MB (open squares) and HT (filled circles) data from the years 2003 and 2004 combined. The horizontal bars indicate the ranges of the pT intervals. The curve shows a NLO calculation. (b) Comparison of theory and data. The band indicates the experimental systematic uncertainty. The upper (lower) dashed line indicates the relative change of the NLO calculation when it is evaluated at &mu = pT/2 (&mu = 2pT).

The longitudinal double-spin asymmetry ALL in p+p-> jet +X at sqrt(s) = 200 GeV versus jet pT. The uncertainties on the data points are statistical. The gray band indicates the systematic uncertainty from the beam polarization measurement, and the hatched band the total systematic uncertainty. The curves show predictions based on deep-inelastic scattering parametrizations of gluon polarization.


Strange particle production in p + p collisions at s**(1/2) = 200-GeV.

The STAR collaboration Abelev, B.I. ; Adams, J. ; Aggarwal, M.M. ; et al.
Phys.Rev.C 75 (2007) 064901, 2007.
Inspire Record 722757 DOI 10.17182/hepdata.96848

We present strange particle spectra and yields measured at mid-rapidity in $\sqrt{\text{s}}=200$ GeV proton-proton ($p+p$) collisions at RHIC. We find that the previously observed universal transverse mass ($\mathrm{m_{T}}\equiv\sqrt{\mathrm{p_{T}}^{2}+\mathrm{m}^{2}}$) scaling of hadron production in $p+p$ collisions seems to break down at higher \mt and that there is a difference in the shape of the \mt spectrum between baryons and mesons. We observe mid-rapidity anti-baryon to baryon ratios near unity for $\Lambda$ and $\Xi$ baryons and no dependence of the ratio on transverse momentum, indicating that our data do not yet reach the quark-jet dominated region. We show the dependence of the mean transverse momentum (\mpt) on measured charged particle multiplicity and on particle mass and infer that these trends are consistent with gluon-jet dominated particle production. The data are compared to previous measurements from CERN-SPS, ISR and FNAL experiments and to Leading Order (LO) and Next to Leading order (NLO) string fragmentation model predictions. We infer from these comparisons that the spectral shapes and particle yields from $p+p$ collisions at RHIC energies have large contributions from gluon jets rather than quark jets.

14 data tables

Corrected mid-rapidity (|y| < 0.5) pT spectra for $K^{+}$, $K^{−}$, $K^{0}_{S}$, Λ, Ξ, and Ω. Λ spectra that have been corrected for feed-down are shown as open symbols in the Λ panel. The dashed lines are fits using Equation 11 except for the $\Omega+\overline{\Omega}$ where the fit uses Equation 9. The error bars displayed include systematic errors while the fits were done using statistical errors only for all species except the charged kaons.

Corrected mid-rapidity (|y| < 0.5) pT spectra for $K^{+}$, $K^{−}$, $K^{0}_{S}$, Λ, Ξ, and Ω. Λ spectra that have been corrected for feed-down are shown as open symbols in the Λ panel. The dashed lines are fits using Equation 11 except for the $\Omega+\overline{\Omega}$ where the fit uses Equation 9. The error bars displayed include systematic errors while the fits were done using statistical errors only for all species except the charged kaons.

Corrected mid-rapidity (|y| < 0.5) pT spectra for $K^{+}$, $K^{−}$, $K^{0}_{S}$, Λ, Ξ, and Ω. Λ spectra that have been corrected for feed-down are shown as open symbols in the Λ panel. The dashed lines are fits using Equation 11 except for the $\Omega+\overline{\Omega}$ where the fit uses Equation 9. The error bars displayed include systematic errors while the fits were done using statistical errors only for all species except the charged kaons.

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Delta(phi) Delta(eta) correlations in central Au + Au collisions at s(NN)**(1/2) = 200-GeV.

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.C 75 (2007) 034901, 2007.
Inspire Record 721060 DOI 10.17182/hepdata.102086

We report charged-particle pair correlation analyses in the space of Delta -phi (azimuth) and Delta -eta (pseudo-rapidity), for central Au + Au collisions at sqrt{s_{NN}} = 200 GeV in the STAR detector. The analysis involves unlike-sign charge pairs and like-sign charge pairs, which are transformed into charge-dependent (CD) signals and charge-independent (CI) signals. We present detailed parameterizations of the data. A model featuring dense gluonic hot spots as first proposed by van Hove predicts that the observables under investigation would have sensitivity to such a substructure should it occur, and the model also motivates selection of transverse momenta in the range 0.8 < p_t < 2.0$ GeV/c. Both CD and CI correlations of high statistical significance are observed and possible interpretations are discussed.

16 data tables

FIG. 1: a) left side: The $\Delta\phi$ - $\Delta\eta$ correlation data for unlike-sign charge particle pairs from the Star central trigger dataset shown in a 2-dimensional (2-D) perspective plot. The particle tracks have 0.8 GeV/c < $p_t$ < 2.0 GeV/c and |$\eta$| < 1.0. The structure that looks like tiles on a roof is due to the readout boundary effects of the 12 sector TPC. b) right side: The similar correlation data for like-sign charge particle pairs is shown.

FIG. 1: a) left side: The $\Delta\phi$ - $\Delta\eta$ correlation data for unlike-sign charge particle pairs from the Star central trigger dataset shown in a 2-dimensional (2-D) perspective plot. The particle tracks have 0.8 GeV/c < $p_t$ < 2.0 GeV/c and |$\eta$| < 1.0. The structure that looks like tiles on a roof is due to the readout boundary effects of the 12 sector TPC. b) right side: The similar correlation data for like-sign charge particle pairs is shown.

FIG. 2: a) left side: The correlation data for the ratio of the histograms of same-event-pairs to mixed-event-pairs for unlike-sign charged pairs, shown in a two-dimensional (2-D) perspective plot $\Delta\phi$ - $\Delta\eta$. The plot was normalized to a mean of 1. b) right side: The similar correlation data for like-sign charge pairs.

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Scaling Properties of Hyperon Production in Au+Au Collisions at sqrt(s_NN) = 200 GeV

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.Lett. 98 (2007) 062301, 2007.
Inspire Record 718755 DOI 10.17182/hepdata.98928

We present the scaling properties of Lambda, Xi, Omega and their anti-particles produced at mid-rapidity in Au+Au collisions at RHIC at sqrt(s_NN) = 200 GeV. The yield of multi-strange baryons per participant nucleon increases from peripheral to central collisions more rapidly than the Lambda yield, which appears to correspond to an increasing strange quark density of matter produced. The value of the strange phase space occupancy factor gamma_s, obtained from a thermal model fit to the data, approaches unity for the most central collisions. We also show that the nuclear modification factors, R_CP, of Lambda and Xi are consistent with each other and with that of protons in the transverse momentum range 2.0 < p_T < 5.0 GeV/c. This scaling behaviour is consistent with a scenario of hadron formation from constituent quark degrees of freedom through quark recombination or coalescence.

6 data tables

Transverse momentum distributions of (a) $\Lambda(\overline{\Lambda})$ for $|y|<1.0$, (b) $\Xi^{-}(\overline{\Xi}^{+})$ for $|y|<0.75$ and (c) $\Omega^{-}+\overline{\Omega}^{+}$ for $|y|<0.75$ in Au+Au collisions at $\sqrt{s_{NN}}$ as a function of centrality. The $\Lambda$ spectra were corrected for weak decay of $\Xi$, $\Xi^{0}$ and $\Omega$. Scale factors were applied to the spectra for clarity. Only statistical errors are shown. The dashed curves show a Boltzmann fit to the $\Lambda$, $\Xi^{-}$ and $\Omega^{-}+\overline{\Omega}^{+}$ data, the fits to the $\overline{\Lambda}$ and $\overline{\Xi}^{+}$ are omitted for clarity.

Transverse momentum distributions of (a) $\Lambda(\overline{\Lambda})$ for $|y|<1.0$, (b) $\Xi^{-}(\overline{\Xi}^{+})$ for $|y|<0.75$ and (c) $\Omega^{-}+\overline{\Omega}^{+}$ for $|y|<0.75$ in Au+Au collisions at $\sqrt{s_{NN}}$ as a function of centrality. The $\Lambda$ spectra were corrected for weak decay of $\Xi$, $\Xi^{0}$ and $\Omega$. Scale factors were applied to the spectra for clarity. Only statistical errors are shown. The dashed curves show a Boltzmann fit to the $\Lambda$, $\Xi^{-}$ and $\Omega^{-}+\overline{\Omega}^{+}$ data, the fits to the $\overline{\Lambda}$ and $\overline{\Xi}^{+}$ are omitted for clarity.

Transverse momentum distributions of (a) $\Lambda(\overline{\Lambda})$ for $|y|<1.0$, (b) $\Xi^{-}(\overline{\Xi}^{+})$ for $|y|<0.75$ and (c) $\Omega^{-}+\overline{\Omega}^{+}$ for $|y|<0.75$ in Au+Au collisions at $\sqrt{s_{NN}}$ as a function of centrality. The $\Lambda$ spectra were corrected for weak decay of $\Xi$, $\Xi^{0}$ and $\Omega$. Scale factors were applied to the spectra for clarity. Only statistical errors are shown. The dashed curves show a Boltzmann fit to the $\Lambda$, $\Xi^{-}$ and $\Omega^{-}+\overline{\Omega}^{+}$ data, the fits to the $\overline{\Lambda}$ and $\overline{\Xi}^{+}$ are omitted for clarity.

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Identified baryon and meson distributions at large transverse momenta from Au + Au collisions at s(NN)**(1/2) = 200-GeV.

The STAR collaboration Abelev, B.I. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.Lett. 97 (2006) 152301, 2006.
Inspire Record 718231 DOI 10.17182/hepdata.98860

Transverse momentum spectra of $\pi^{\pm}$, $p$ and $\bar{p}$ up to 12 GeV/c at mid-rapidity in centrality selected Au+Au collisions at $\sqrt{s_{_{NN}}} = 200$ GeV are presented. In central Au+Au collisions, both $\pi^{\pm}$ and $p(\bar{p})$ show significant suppression with respect to binary scaling at $p_T > $ 4 GeV/c. Protons and anti-protons are less suppressed than $\pi^{\pm}$, in the range 1.5 $< p_{T} <$6 GeV/c. The $\pi^-/\pi^+$ and $\bar{p}/p$ ratios show at most a weak $p_T$ dependence and no significant centrality dependence. The $p/\pi$ ratios in central Au+Au collisions approach the values in p+p and d+Au collisions at $p_T >$ 5 GeV/c. The results at high $p_T$ indicate that the partonic sources of $\pi^{\pm}$, $p$ and $\bar{p}$ have similar energy loss when traversing the nuclear medium.

8 data tables

Centrality dependence of mid-rapidity ($|y|$ $<$ 0.5) $\pi^{\pm}$, p and $\bar{p}$ in invariant yields versus $p_{T}$ from 200 GeV Au+Au collisions.

Centrality dependence of mid-rapidity ($|y|$ $<$ 0.5) $\pi^{\pm}$, p and $\bar{p}$ in invariant yields versus $p_{T}$ from 200 GeV Au+Au collisions.

Centrality dependence of mid-rapidity ($|y|$ $<$ 0.5) $\pi^{\pm}$, p and $\bar{p}$ in invariant yields versus $p_{T}$ from 200 GeV Au+Au collisions.

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The Multiplicity dependence of inclusive p(t) spectra from p-p collisions at s**(1/2) = 200-GeV

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.D 74 (2006) 032006, 2006.
Inspire Record 719969 DOI 10.17182/hepdata.102084

We report measurements of transverse momentum $p_t$ spectra for ten event multiplicity classes of p-p collisions at $\sqrt{s} = 200$ GeV. By analyzing the multiplicity dependence we find that the spectrum shape can be decomposed into a part with amplitude proportional to multiplicity and described by a L\'evy distribution on transverse mass $m_t$, and a part with amplitude proportional to multiplicity squared and described by a gaussian distribution on transverse rapidity $y_t$. The functional forms of the two parts are nearly independent of event multiplicity. The two parts can be identified with the soft and hard components of a two-component model of p-p collisions. This analysis then provides the first isolation of the hard component of the $p_t$ spectrum as a distribution of simple form on $y_t$.

5 data tables

FIG. 1: Corrected and normalized charged-particle spectra on transverse momentum $p_t$ (left) and transverse rapidity $y_t$ (right) for 10 event multiplicity classes, displaced upward by successive factors 40 relative to $\hat{n}_{ch}$ = 1 at bottom. Solid curves represent reference function $n_s/n_{ch} · S_0(y_t)$ (cf.Sec. IV C). Dotted curves are spline fits to guide the eye.

FIG. 1: Corrected and normalized charged-particle spectra on transverse momentum $p_t$ (left) and transverse rapidity $y_t$ (right) for 10 event multiplicity classes, displaced upward by successive factors 40 relative to $\hat{n}_{ch}$ = 1 at bottom. Solid curves represent reference function $n_s/n_{ch} · S_0(y_t)$ (cf.Sec. IV C). Dotted curves are spline fits to guide the eye.

FIG. 2. Left: Relative residuals from power-law fits to $p_{t}$ spectra in Fig. 1. The hatched band represents the expected statistical errors for STAR data. Right: Exponents $n$ from power-law fits to data (solid points) and to corresponding twocomponent fixed-model functions (open circles, see Sec. VI) compared to the two-component fixed-model Lévy exponent $12.8 \pm 0.15$ (hatched band). NOTE 1: For points with invisible error bars, the point size was considered as an absolute upper limit for the uncertainty. NOTE 2: The "data_stat" uncertainty corresponds to the expected statistical error (hatched band).

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The Energy dependence of p(t) angular correlations inferred from mean-p(t) fluctuation scale dependence in heavy ion collisions at the SPS and RHIC

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
J.Phys.G 34 (2007) 451-466, 2007.
Inspire Record 717232 DOI 10.17182/hepdata.102948

We present the first study of the energy dependence of $p_t$ angular correlations inferred from event-wise mean transverse momentum $<p_{t} >$ fluctuations in heavy ion collisions. We compare our large-acceptance measurements at CM energies $\sqrt{s_{NN}} =$ 19.6, 62.4, 130 and 200 GeV to SPS measurements at 12.3 and 17.3 GeV. $p_t$ angular correlation structure suggests that the principal source of $p_t$ correlations and fluctuations is minijets (minimum-bias parton fragments). We observe a dramatic increase in correlations and fluctuations from SPS to RHIC energies, increasing linearly with $\ln \sqrt{s_{NN}}$ from the onset of observable jet-related $<p_{t}>$ fluctuations near 10 GeV.

5 data tables

Per-particle fluctuation dependence on pseudorapidity scale $\delta\eta$ in central collisions.

Per-particle fluctuation dependence on pseudorapidity scale $\delta\eta$ in central collisions.

Centrality dependence of $<p_t>$ fluctuations in the STAR acceptance for four energies. $\nu$ is the mean participant path length (please consult text).

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Direct observation of dijets in central Au + Au collisions at s(NN)**(1/2) = 200-GeV.

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.Lett. 97 (2006) 162301, 2006.
Inspire Record 715470 DOI 10.17182/hepdata.98572

The STAR Collaboration at RHIC reports measurements of azimuthal correlations of high transverse momentum (p_T) charged hadrons in Au+Au collisions at higher p_T than reported previously. As p_T is increased, a narrow, back-to-back peak emerges above the decreasing background, providing a clear dijet signal for all collision centralities studied. Using these correlations, we perform a systematic study of dijet production and suppression in nuclear collisions, providing new constraints on the mechanisms underlying partonic energy loss in dense matter.

5 data tables

Centrality dependence (number of participants Npart) of near-side ($|\Delta\phi|$<0.63) yields in d+Au and Au+Au collisions at 200 GeV, for $8 < p_T^{trig} < 15$ GeV/c and various $p_T^{assoc}$ ranges. Data for $3 < p_T^{assoc} < 4$ GeV/c are scaled by 1.5 for clarity. The point with the smallest Npart is the yield in d+Au collisions and the others are those in Au+Au collisions.

Centrality dependence (number of participants Npart) of away-side ($|\Delta\phi-\pi|$<0.63) yields in d+Au and Au+Au collisions at 200 GeV, for $8 < p_T^{trig} < 15$ GeV/c and various $p_T^{assoc}$ ranges. Data for $3 < p_T^{assoc} < 4$ GeV/c are scaled by 1.5 for clarity. The point with the smallest Npart is the yield in d+Au collisions and the others are those in Au+Au collisions.

Trigger-normalized fragment distribution $D(z_T)$ with $8 < p_T^{trig} < 15$ GeV/c for near-side ($|\Delta\phi|$<0.63) correlations in d+Au collisions at 200 GeV.

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Strange baryon resonance production in s(NN)**(1/2) = 200-GeV p + p and Au + Au collisions.

The STAR collaboration Abelev, B.I. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.Lett. 97 (2006) 132301, 2006.
Inspire Record 715471 DOI 10.17182/hepdata.102937

We report the measurements of $\Sigma (1385)$ and $\Lambda (1520)$ production in $p+p$ and $Au+Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV from the STAR collaboration. The yields and the $p_{T}$ spectra are presented and discussed in terms of chemical and thermal freeze-out conditions and compared to model predictions. Thermal and microscopic models do not adequately describe the yields of all the resonances produced in central $Au+Au$ collisions. Our results indicate that there may be a time-span between chemical and thermal freeze-out during which elastic hadronic interactions occur.

2 data tables

The transverse mass spectra for $\Sigma^{∗}$ and $\Lambda^{∗}$ in p+p and in central Au+Au collisions at $\sqrt{s_{NN}} = 200$ GeV. Statistical and systematical errors are included.

Resonance to stable particle ratios for p + p and Au + Au collisions. The ratios are normalized to unity in p + p and compared to thermal and UrQMD model predictions for central Au + Au [8, 12]. Statistical and systematic uncertainties are included in the error bars. (In the paper figure, K*/K dNCh/dy axis is shifted +30 for visual purposes to seperate the error bar contributions.)


Forward neutral pion production in p+p and d+Au collisions at s(NN)**(1/2) = 200-GeV.

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.Lett. 97 (2006) 152302, 2006.
Inspire Record 710186 DOI 10.17182/hepdata.98968

Measurements of the production of forward pi0 mesons from p+p and d+Au collisions at sqrt(s_NN)=200 GeV are reported. The p+p yield generally agrees with next-to-leading order perturbative QCD calculations. The d+Au yield per binary collision is suppressed as eta increases, decreasing to ~30% of the p+p yield at <eta>=4.00, well below shadowing expectations. Exploratory measurements of azimuthal correlations of the forward pi0 with charged hadrons at eta~0 show a recoil peak in p+p that is suppressed in d+Au at low pion energy. These observations are qualitatively consistent with a saturation picture of the low-x gluon structure of heavy nuclei.

7 data tables

Inclusive $\pi^{0}$ cross section for p+p collisions versus the leading $\pi^{0}$ energy ($E_{\pi}$) averaged over 5 GeV bins at fixed pseudorapidity ($\eta$). The error bars combine statistical and point-to-point systematic errors. The curves are NLO pQCD calculations using two sets of fragmentation functions (FF).

Inclusive $\pi^{0}$ cross section per binary collision for d+Au collisions, as in Fig. 1. The curves are calculations described in the text. (Inset) Diphoton invariant mass spectrum for data (stars), normalized to simulation (histogram).

Nuclear modification factor ($R_{dAu}$) for minimum-bias d+Au collisions versus transverse momentum ($p_{T}$). The solid circles are for $\pi^{0}$ mesons. The open circles and boxes are for negative hadrons [10]. The error bars are statistical, while the shaded boxes are point-to-point systematic errors. (Inset) $R_{dAu}$ for $\pi^{0}$ mesons with the ratio of curves in Figs. 2 and 1.

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Identified hadron spectra at large transverse momentum in p + p and d + Au collisions at s(NN)**(1/2) = 200-GeV.

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Lett.B 637 (2006) 161-169, 2006.
Inspire Record 709170 DOI 10.17182/hepdata.85695

We present the transverse momentum (pT) spectra for identified charged pions, protons and anti-protons from p+p and d+Au collisions at \sqrts_NN = 200 GeV. The spectra are measured around midrapidity (|y| &lt; 0.5) over the range of 0.3 &lt; pT &lt; 10 GeV/c with particle identification from the ionization energy loss and its relativistic rise in the Time Projection Chamber and Time-of-Flight in STAR. The charged pion and proton+anti-proton spectra at high pT in p+p and d+Au collisions are in good agreement with a phenomenological model (EPOS) and with the next-to-leading order perturbative quantum chromodynamic (NLO pQCD) calculations with a specific fragmentation scheme and factorization scale. We found that all proton, anti-proton and charged pion spectra in p+p collisions follow xT-scalings for the momentum range where particle production is dominated by hard processes (pT > 2 GeV/c). The nuclear modification factor around midrapidity are found to be greater than unity for charged pions and to be even larger for protons at 2 &lt; pT &lt; 5 GeV/c.

26 data tables

Transverse momentum distribution for $\pi^+$ production in d+Au minbias events in the mid rapidity region, $|y|<0.5$.

Transverse momentum distribution for $\pi^+$ production in p+p NSD events in the mid rapidity region, $|y|<0.5$.

Transverse momentum distribution for $\pi^+$ production in d+Au collisions with centrality 0-20% in the mid rapidity region, $|y|<0.5$.

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Multiplicity and pseudorapidity distributions of charged particles and photons at forward pseudorapidity in Au + Au collisions at s(NN)**(1/2) = 62.4-GeV.

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.C 73 (2006) 034906, 2006.
Inspire Record 697905 DOI 10.17182/hepdata.98930

We present the centrality dependent measurement of multiplicity and pseudorapidity distributions of charged particles and photons in Au + Au collisions at sqrt{s_NN} = 62.4 GeV. The charged particles and photons are measured in the pseudorapidity region 2.9 < eta < 3.9 and 2.3 < eta < 3.7, respectively. We have studied the scaling of particle production with the number of participating nucleons and the number of binary collisions. The photon and charged particle production in the measured pseudorapidity range has been shown to be consistent with energy independent limiting fragmentation behavior. The photons are observed to follow a centrality independent limiting fragmentation behavior while for the charged particles it is centrality dependent. We have carried out a comparative study of the pseudorapidity distributions of positively charged hadrons, negatively charged hadrons, photons, pions, net protons in nucleus--nucleus collisions and pseudorapidity distributions from p+p collisions. From these comparisons we conclude that baryons in the inclusive charged particle distribution are responsible for the observed centrality dependence of limiting fragmentation. The mesons are found to follow an energy independent behavior of limiting fragmentation while the behavior of baryons seems to be energy dependent.

11 data tables

(Color Online) Variation of $N_{ch}$ normalized to the number of participating nucleon pair in the FTPC coverage $(2.9 \leq \eta \leq 3.9)$ and $N_{\gamma}$ normalized to the number of participating nucleon pair in the PMD acceptance $(2.3 \leq \eta \leq 3.7)$ as a function of $N_{part}$. The lower band shows the uncertainty in the ratio due to uncertainties in $N_{part}$ calculations.

(Color Online) Variation of $N_{ch}$ normalized to the number of participating nucleon pair in the FTPC coverage $(2.9 \leq \eta \leq 3.9)$ and $N_{\gamma}$ normalized to the number of participating nucleon pair in the PMD acceptance $(2.3 \leq \eta \leq 3.7)$ as a function of $N_{part}$. The lower band shows the uncertainty in the ratio due to uncertainties in $N_{part}$ calculations.

(Color Online) Variation of $N_{ch}$ normalized to the number of collisions in the FTPC coverage $(2.9 \leq \eta \leq 3.9)$ and $N_{\gamma}$ normalized to number of collisions, in the PMD coverage $(2.3 \leq \eta \leq 3.7)$ as a function of $N_{coll}$. The lower band shows the uncertainty in the ratio due to uncertainties in $N_{coll}$ calculations.

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Proton Lambda correlations in central Au + Au collisions at s(NN)**(1/2) = 200-GeV.

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.C 74 (2006) 064906, 2006.
Inspire Record 696676 DOI 10.17182/hepdata.98927

We report on p-Lambda, p-Lambda bar, p bar-Lambda and p bar-Lambda bar correlation functions constructed in central Au-Au collisions at sqrt(s_NN)=200GeV by the STAR experiment at RHIC. The proton and lambda source size is inferred from the p-Lambda and p bar-Lambda bar correlation functions. They are found to be smaller than the pion source size also measured by the STAR detector. This could be a consequence of the collision fireball's collective expansion. The p-Lambda bar and p bar-Lambda correlations, which are measured for the first time, exhibit a large anti-correlation. Annihilation channels and/or a negative real part of the spin-averaged scattering length must be included in the final-state interactions calculation to reproduce the measured correlation function.

8 data tables

Invariant mass of the selected $\Lambda$ background not substracted with $0.3 < p_t < 2.0$ GeV/c. The y axis represents the number of candidates used in this analysis.

Invariant mass of the selected $\bar{\Lambda}$ background not substracted with $0.3 < p_t < 2.0$ GeV/c. The y axis represents the number of candidates used in this analysis.

The purity and momentum-resolution corrected correlation functions $C_{true}(k^{*})$ for $p-\Lambda$, $\bar{p}-\bar{\Lambda}$ (a), $\bar{p}-\Lambda$, $p-\bar{\Lambda}$ (b). Curves correspond to fits done using the Lednicky and Lyuboshitz analytical model [12].

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Directed flow in Au + Au collisions at s(NN)**(1/2) = 62-GeV.

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.C 73 (2006) 034903, 2006.
Inspire Record 695404 DOI 10.17182/hepdata.102947

We present the directed flow ($v_1$) measured in Au+Au collisions at $\sqrt{s_{_{NN}}}$ = 62.4 GeV in the mid-pseudorapidity region $|\eta|<1.3$ and in the forward pseudorapidity region $2.5 < |\eta| < 4.0$. The results are obtained using the three-particle cumulant method, the event plane method with mixed harmonics, and for the first time at the Relativistic Heavy Ion Collider (RHIC), the standard method with the event plane reconstructed from spectator neutrons. Results from all three methods are in good agreement. Over the pseudorapidity range studied, charged particle directed flow is in the direction opposite to that of fragmentation neutrons.

19 data tables

Directed flow of charged particles as a function of pseudorapidity, for centrality 10%-70%.

Directed flow of charged particles as a function of pseudorapidity, for centrality 10%-70%.

Directed flow of charged particles as a function of pseudorapidity, for centrality 10%-70%.

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Transverse-momentum p(t) correlations on (eta,Phi) from mean-p(t) fluctuations in Au - Au collisions at s(NN)**(1/2) = 200-GeV.

The STAR collaboration Adams, John ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
J.Phys.G 32 (2006) L37-L48, 2006.
Inspire Record 693136 DOI 10.17182/hepdata.102092

We present first measurements of the pseudorapidity and azimuth $(\eta,\phi)$ bin-size dependence of event-wise mean transverse momentum $<p_{t} >$ fluctuations for Au-Au collisions at $\sqrt{s_{NN}} = 200$ GeV. We invert that dependence to obtain $p_t$ autocorrelations on differences $(\eta_\Delta,\phi_\Delta)$ interpreted to represent velocity/temperature distributions on ($\eta,\phi$). The general form of the autocorrelations suggests that the basic correlation mechanism is parton fragmentation. The autocorrelations vary strongly with collision centrality, which suggests that fragmentation is strongly modified by a dissipative medium in the more central

1 data table

Correlation amplitudes $B_{1}, B_{2}, B_{3}$ as well as positive-peak widths for pseudorapidity ($\sigma_{\eta_{1}}$) and azimuth ($\sigma_{\phi_{1}}$), plotted on mean participant path length $\nu$.


Incident energy dependence of p(t) correlations at RHIC.

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.C 72 (2005) 044902, 2005.
Inspire Record 681688 DOI 10.17182/hepdata.102946

We present results for two-particle transverse momentum correlations, <dpt,i dpt,j>, as a function of event centrality for Au+Au collisions at sqrt(sNN) = 20, 62, 130, and 200 GeV at the Relativistic Heavy Ion Collider. We observe correlations decreasing with centrality that are similar at all four incident energies. The correlations multiplied by the multiplicity density increase with incident energy and the centrality dependence may show evidence of processes such as thermalization, minijet production, or the saturation of transverse flow. The square root of the correlations divided by the event-wise average transverse momentum per event shows little or no beam energy dependence and generally agrees with previous measurements at the Super Proton Synchrotron.

8 data tables

Average transverse momentum per event for Au+Au at $\sqrt{s_{NN}}$ = 20 GeV for the 5% most central collisions.

Average transverse momentum per event for Au+Au at $\sqrt{s_{NN}}$ = 62 GeV for the 5% most central collisions.

Average transverse momentum per event for Au+Au at $\sqrt{s_{NN}}$ = 130 GeV for the 5% most central collisions.

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Multi-strange baryon elliptic flow in Au + Au collisions at s(NN)**(1/2) = 200-GeV.

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.Lett. 95 (2005) 122301, 2005.
Inspire Record 681161 DOI 10.17182/hepdata.102945

We report on the first measurement of elliptic flow $v_2(p_T)$ of multi-strange baryons $\Xi+\bar{Xi}$ and $\Omega+\bar{Omega} in heavy-ion collisions. In minimum bias Au+Au collisions at sqrt(s_NN) = 200 GeV, a significant amount of elliptic flow, comparable to other non-strange baryons, is observed for multi-strange baryons which are expected to be particularly sensitive to the dynamics of the partonic stage of heavy-ion collisions. The $p_T$ dependence of $v_2$ of the multi-strange baryons confirms the number of constituent quark scaling previously observed for lighter hadrons. These results support the idea that a substantial fraction of the observed collective motion is developed at the early partonic stage in ultra-relativistic nuclear collisions at RHIC.

5 data tables

$\Xi^{-} + \Xi^{+}$ invariant mass distribution from minimum bias (0–80%) Au + Au collisions at $\sqrt{s_{NN}}$ = 200 GeV.

$\Omega^{-} + \Omega^{+}$ invariant mass distribution from minimum bias (0–80%) Au + Au collisions at $\sqrt{s_{NN}}$ = 200 GeV.

Azimuthal distributions with respect to the event plane of the $\Xi^{-} + \Xi^{+}$ and $\Omega^{-} + \Omega^{+}$ raw yields.

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Multiplicity and pseudorapidity distributions of photons in Au + Au collisions at s(NN)**(1/2) = 62.4-GeV.

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.Lett. 95 (2005) 062301, 2005.
Inspire Record 676188 DOI 10.17182/hepdata.98929

We present the first measurement of multiplicity and pseudorapidity distributions of photons in the pseudorapidity region 2.3 $\le$ $\eta$ $\le$ 3.7 for different centralities in Au + Au collisions at $\sqrt{s_{NN}}$ = 62.4 GeV. We find that the photon yield in this pseudorapidity range scales with the number of participating nucleons at all collision centralities studied. The pseudorapidity distribution of photons, dominated by neutral pion decays, has been compared to those of identified charged pions, photons, and inclusive charged particles from heavy ion and nucleon-nucleon collisions at various energies. The photon production in the measured pseudorapidity region has been shown to be consistent with the energy and centrality independent limiting fragmentation scenario.

3 data tables

${dN_{\gamma}}\over{d\eta}$ for various event centrality classes compared to HIJING and AMPT model calculations.

Variation of $N_{\gamma}$ per participant pair in PMD coverage $(2.3 \leq \eta \leq 3.7)$ as a function of $N_{part}$. The lower band reflects uncertainties in $N_{part}$ calculations.

(Color Online) Estimated ${dN_{\pi^{0}}}\over{dy}$ from ${dN_{\gamma}}\over{dy}$ normalized to $N_{part}$, as compared to ${dN_{\pi^{\pm}}}\over{dy}$ normalized to $N_{part}$, as a function of $y-y_{beam}$ for central collisions at various collision energies.


Distributions of charged hadrons associated with high transverse momentum particles in p p and Au + Au collisions at s(NN)**(1/2) = 200-GeV.

The STAR collaboration Adams, J. ; Adler, C. ; Aggarwal, M.M. ; et al.
Phys.Rev.Lett. 95 (2005) 152301, 2005.
Inspire Record 675307 DOI 10.17182/hepdata.96233

Charged hadrons in 0.15 < pt < 4 GeV/c associated with particles of pt^trig > 4 GeV/c are reconstructed in pp and Au+Au collisions at sqrt(s_NN)=200 GeV. The associated multiplicity and pt magnitude sum are found to increase from pp to central Au+Au collisions. The associated pt distributions, while similar in shape on the near side, are significantly softened on the away side in central Au+Au relative to pp and not much harder than that of inclusive hadrons. The results, consistent with jet quenching, suggest that the away-side fragments approach equilibration with the medium traversed.

25 data tables

Dphi correlation functions for 0.15 < pT < 4 GEV/c and 4 < p_T^trig < 6 GEV/c.

Dphi correlation functions for 0.15 < pT < 4 GEV/c and 4 < p_T^trig < 6 GEV/c.

Dphi correlation functions for 2 < pT < 4 GEV/c and 4 < p_T^trig < 6 GEV/c.

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K*(892) resonance production in Au + Au and p + p collisions at s(NN)**(1/2) = 200-GeV at STAR.

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.C 71 (2005) 064902, 2005.
Inspire Record 666578 DOI 10.17182/hepdata.100595

The short-lived $K(892)^{*}$ resonance provides an efficient tool to probe properties of the hot and dense medium produced in relativistic heavy-ion collisions. We report measurements of $K^{*}$ in $\sqrt{s_{_{NN}}}$ = 200 GeV Au+Au and $p+p$ collisions reconstructed via its hadronic decay channels $K(892)^{*0} \to K\pi$ and $K(892)^{*\pm} \to K_S^0\pi^{\pm}$ using the STAR detector at RHIC. The $K^{*0}$ mass has been studied as a function of $p_T$ in minimum bias $p+p$ and central Au+Au collisions. The $K^{*}$ $p_T$ spectra for minimum bias $p+p$ interactions and for Au+Au collisions in different centralities are presented. The $K^{*}/K$ yield ratios for all centralities in Au+Au collisions are found to be significantly lower than the ratio in minimum bias $p+p$ collisions, indicating the importance of hadronic interactions between chemical and kinetic freeze-outs. A significant non-zero $K^{*0}$ elliptic flow ($v_2$) is observed in Au+Au collisions and compared to the $K_S^0$ and $\Lambda$ $v_2$. The nuclear modification factor of $K^{*}$ at intermediate $p_{T}$ is similar to that of $K_{S}^{0}$, but different from $\Lambda$. This establishes a baryon-meson effect over a mass effect in the particle production at intermediate $p_T$ ($2 < p_T \leq 4$ GeV/$c$).

22 data tables

$K_S^0$ signal observed in the $\pi^+\pi^−$ invariant mass distribution reconstructed from the decay topology method via $K_S^0->\pi^+\pi^−$ in $p+p$ collisions. The dashed curve depicts the Gaussian fit function plus a linear function representing the background.

The $K\pi$ invariant mass distributions after event-mixing background subtraction (open star symbols) and like-sign background subtraction with different daughter momentum cuts (0.2 < Kaon and Pion p < 10 GeV/$c$ for filled square symbols, 0.2 < Kaon $p$ < 0.7 GeV/$c$ and 0.2 < Pion $p$ < 10 GeV/$c$ for open triangle symbols) demonstrating the sources of the residual background in minimum bias Au+Au collisions. The open triangle symbols have been scaled up by a factor of 3 in order to increase the visibility. The arrow depicts the standard $K^{*0}$ mass of 896.1 MeV/$c^2$.

The $K\pi$ invariant mass distribution integrated over the $K^*$ $p_T$ for central Au+Au (upper panel) and minimum bias $p + p$ (lower panel) interactions after the mixed-event background subtraction. The solid curves are the fits to Eq. 5 with $T_{fo}$ = 120 MeV and $p_T$ = 1.8 GeV/$c$ for central Au+Au and $T_{fo}$ = 160 MeV and $p_T$ = 0.8 GeV/$c$ for p+p, respectively. The dashed lines are the linear function representing the residual background.

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Pion interferometry in Au + Au collisions at s(NN)**(1/2) = 200-GeV.

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.C 71 (2005) 044906, 2005.
Inspire Record 664843 DOI 10.17182/hepdata.93263

We present a systematic analysis of two-pion interferometry in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV using the STAR detector at RHIC. We extract the HBT radii and study their multiplicity, transverse momentum, and azimuthal angle dependence. The Gaussianess of the correlation function is studied. Estimates of the geometrical and dynamical structure of the freeze-out source are extracted by fits with blast wave parameterizations. The expansion of the source and its relation with the initial energy density distribution is studied.

44 data tables

1D correlation function for different values of SL (antisplitting cut).

1D correlation functions for differeny values of the maximum fraction of merged hits allowed.

Projections of the 3 dimensional correlation function and corresponding fits for negative pions from the 0-5% most central events and k_T = [150,250] MeV/c according to the standard and Bowler-Sinyukov procedures.

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