Centrality dependence of charged hadron production in deuteron+gold and nucleon+gold collisions at sqrt(s_NN)=200 GeV

The PHENIX collaboration Adler, S.S. ; Afanasiev, S. ; Aidala, C. ; et al.
Phys.Rev.C 77 (2008) 014905, 2008.
Inspire Record 758544 DOI 10.17182/hepdata.146750

We present transverse momentum (p_T) spectra of charged hadrons measured in deuteron-gold and nucleon-gold collisions at \sqrts = 200 GeV for four centrality classes. Nucleon-gold collisions were selected by tagging events in which a spectator nucleon was observed in one of two forward rapidity detectors. The spectra and yields were investigated as a function of the number of binary nucleon-nucleon collisions, \nu, suffered by deuteron nucleons. A comparison of charged particle yields to those in p+p collisions show that the yield per nucleon-nucleon collision saturates with \nu for high momentum particles. We also present the charged hadron to neutral pion ratios as a function of p_T.

21 data tables

<p>Charged hadron spectra for centrality selected d+Au collisions.</p>

<p>Charged hadron spectra for centrality selected d+Au collisions.</p>

<p>Charged hadron spectra for centrality selected d+Au collisions.</p>

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Detailed measurement of the $e^+ e^-$ pair continuum in $p+p$ and Au+Au collisions at $\sqrt{s_{NN}} = 200$ GeV and implications for direct photon production

The PHENIX collaboration Adare, A. ; Afanasiev, S. ; Aidala, C. ; et al.
Phys.Rev.C 81 (2010) 034911, 2010.
Inspire Record 838580 DOI 10.17182/hepdata.145190

PHENIX has measured the e^+e^- pair continuum in sqrt(s_NN)=200 GeV Au+Au and p+p collisions over a wide range of mass and transverse momenta. The e^+e^- yield is compared to the expectations from hadronic sources, based on PHENIX measurements. In the intermediate mass region, between the masses of the phi and the J/psi meson, the yield is consistent with expectations from correlated c^bar-c production, though other mechanisms are not ruled out. In the low mass region (below the phi) the p+p inclusive mass spectrum is well described by known contributions from light meson decays. In contrast, the Au+Au minimum bias inclusive mass spectrum in this region shows an enhancement by a factor of 4.7+/-0.4(stat)+/-1.5(syst)+/-0.9(model) At low mass (m_ee<0.3 GeV/c^2) and high p_T (1<p_T<5 GeV/c) an enhanced e^+e^- pair yield is observed that is consistent with production of virtual direct photons. This excess is used to infer the yield of real direct photons. In central Au+Au collisions, the excess of the direct photon yield over the p+p is exponential in p_T, with inverse slope T=221+/-19(stat)+/-19(syst) MeV. Hydrodynamical models with initial temperatures ranging from T_init ~=300--600 MeV at times of 0.6--0.15 fm/c after the collision are in qualitative agreement with the direct photon data in Au+Au. For low p_T<1 GeV/c the low mass region shows a further significant enhancement that increases with centrality and has an inverse slope of T ~=100 MeV. Theoretical models under predict the low mass, low p_T enhancement.

113 data tables

(Color online) Inclusive mass spectrum of $e^+e^-$ pairs in the PHENIX acceptance in $p$+$p$ collisions compared to the expectations from the decays of light hadrons and correlated decays of charm, bottom, and Drell-Yan. The contribution from hadron decays is independently normalized based on meson measurements in PHENIX. The bottom panel shows the ratio of data to the cocktail of known sources. The systematic uncertainties of the data are shown as boxes, while the uncertainty on the cocktail is shown as band around 1.

(Color online) Inclusive mass spectrum of $e^+e^-$ pairs in the PHENIX acceptance in minimum-bias Au+Au compared to expectations from the decays of light hadrons and correlated decays of charm, bottom, and Drell-Yan. The charm contribution expected if the dynamic correlation of $c$ and $\bar{c}$ is removed is shown separately. Statistical (bars) and systematic (boxes) uncertainties are shown separately. The contribution from hadron decays is independently normalized based on meson measurements in PHENIX. The bottom panel shows the ratio of data to the cocktail of known sources. The systematic uncertainties of the data are shown as boxes, while the uncertainty on the cocktail is shown as band around 1.

(Color online) Inclusive mass spectrum of $e^+e^-$ pairs in the PHENIX acceptance in minimum-bias Au+Au compared to expectations from the decays of light hadrons and correlated decays of charm, bottom, and Drell-Yan. The charm contribution expected if the dynamic correlation of $c$ and $\bar{c}$ is removed is shown separately. Statistical (bars) and systematic (boxes) uncertainties are shown separately. The contribution from hadron decays is independently normalized based on meson measurements in PHENIX. The bottom panel shows the ratio of data to the cocktail of known sources. The systematic uncertainties of the data are shown as boxes, while the uncertainty on the cocktail is shown as band around 1.

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Transverse momentum and centrality dependence of dihadron correlations in Au+Au collisions at sqrt(s_NN)=200 GeV: Jet-quenching and the response of partonic matter

The PHENIX collaboration Adare, A. ; Afanasiev, S. ; Aidala, C. ; et al.
Phys.Rev.C 77 (2008) 011901, 2008.
Inspire Record 751182 DOI 10.17182/hepdata.143605

Azimuthal angle \Delta\phi correlations are presented for charged hadrons from dijets for 0.4 < p_T < 10 GeV/c in Au+Au collisions at sqrt(s_NN) = 200 GeV. With increasing p_T, the away-side distribution evolves from a broad to a concave shape, then to a convex shape. Comparisons to p+p data suggest that the away-side can be divided into a partially suppressed 'head' region centered at Delta\phi ~ \pi, and an enhanced 'shoulder' region centered at Delta\phi ~ \pi +/- 1.1. The p_T spectrum for the 'head' region softens toward central collisions, consistent with the onset of jet quenching. The spectral slope for the 'shoulder' region is independent of centrality and trigger p_T, which offers constraints on energy transport mechanisms and suggests that the 'shoulder' region contains the medium response to energetic jets.

6 data tables

<p>Per-trigger yield versus $\Delta\phi$ for various trigger and partner $p_T$ ($p_T^A$ $\otimes$ $p_T^B$), in $p$+$p$ and 0-20% Au+Au collisions.</p> <p><i>The systematic errors on $v_2$ are represented by "sys. corr." and are dominated by the reaction plane resolution. The fit that accounts for the overlap of the near- and away-side Gaussians at $\Delta\phi_{min}$ gives systematically lower $b_0$ values that that for ZYAM, and is assigned as the differences as one-sided systematic errors on $b_0$ represented by "sys. uncorr.".

<p>Per-trigger yield versus $\Delta\phi$ for various trigger and partner $p_T$ ($p_T^A$ $\otimes$ $p_T^B$), in $p$+$p$ and 0-20% Au+Au collisions.</p> <p><i>The systematic errors on $v_2$ are represented by "sys. corr." and are dominated by the reaction plane resolution. The fit that accounts for the overlap of the near- and away-side Gaussians at $\Delta\phi_{min}$ gives systematically lower $b_0$ values that that for ZYAM, and is assigned as the differences as one-sided systematic errors on $b_0$ represented by "sys. uncorr.".</p></i>

<p>$R_{HS}$ versus $p_T^B$ for $p$+$p$ and Au+Au collisions for four trigger selections.</p> <p><i>The systematic errors on $v_2$ are represented by "sys. corr." and are dominated by the reaction plane resolution. The fit that accounts for the overlap of the near- and away-side Gaussians at $\Delta\phi_{min}$ gives systematically lower $b_0$ values that that for ZYAM, and is assigned as the differences as one-sided systematic errors on $b_0$ represented by "sys. uncorr.".</p></i>

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Production of omega mesons at large transverse momenta in p + p and d + Au collisions at s(NN)**(1/2) = 200-GeV.

The PHENIX collaboration Adler, S.S. ; Afanasiev, S. ; Aidala, C. ; et al.
Phys.Rev.C 75 (2007) 051902, 2007.
Inspire Record 732097 DOI 10.17182/hepdata.143461

The PHENIX experiment at RHIC has measured the invariant cross section for omega-meson production at mid-rapidity in the transverse momentum range 2.5 < p_T < 9.25 GeV/c in p+p and d+Au collisions at sqrt(s_NN) = 200 GeV. Measurements in two decay channels (omega --> pi^0 pi^+ pi^- and omega --> pi^0 gamma) yield consistent results, and the reconstructed omega mass agrees with the accepted value within the p_T range of the measurements. The omega/pi^0 ratio is found to be 0.85 +/- 0.05(stat) +/- 0.09(sys) and 0.94 +/- 0.08(stat) +/- 0.12(sys) in p+p and d+Au collisions respectively, independent of p_T . The nuclear modification factor R_dA is 1.03 +/- 0.12(stat) +/- 0.21(sys) and 0.83 +/- 0.21(stat) +/- 0.17(sys) in minimum bias and central (0-20%) d+Au collisions, respectively.

16 data tables

Invariant cross section of $\omega$ production in $p$+$p$ and $d$+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV measured in $\omega \rightarrow \pi^0\pi^+\pi^-$ and $\omega \rightarrow \pi^0\gamma$ decay channels.

Invariant cross section of $\omega$ production in $p$+$p$ and $d$+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV measured in $\omega \rightarrow \pi^0\pi^+\pi^-$ and $\omega \rightarrow \pi^0\gamma$ decay channels.

Invariant cross section of $\omega$ production in $p$+$p$ and $d$+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV measured in $\omega \rightarrow \pi^0\pi^+\pi^-$ and $\omega \rightarrow \pi^0\gamma$ decay channels.

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Jet structure of baryon excess in Au + Au collisions at s(NN)**(1/2) = 200-GeV.

The PHENIX collaboration Adler, S.S. ; Afanasiev, S. ; Aidala, C. ; et al.
Phys.Rev.C 71 (2005) 051902, 2005.
Inspire Record 656142 DOI 10.17182/hepdata.142148

Two particle correlations between identified meson and baryon trigger particles with 2.5 < p_T < 4.0 GeV/c and lower p_T charged hadrons have been measured at midrapidity by the PHENIX experiment at RHIC in p+p, d+Au and Au+Au collisions at sqrt(s_NN) = 200 GeV. The probability of finding a hadron near in azimuthal angle to the trigger particle is almost identical for leading mesons and baryons for non-central Au+Au. The yield for both trigger baryons and mesons is significantly higher in Au+Au than in p+p and d+Au, except for trigger baryons in central collisions. The baryon excess is likely to arise predominantly from hard scattering processes.

19 data tables

$\Delta\phi$ distributions for meson and baryon triggers with 2.5 < $p_T$ < 4.0 GeV/$c$ and associated charged hadrons with 1.7 < $p_T$ < 2.5 GeV/$c$ for five centralities in Au+Au collisions.

$\Delta\phi$ distributions for meson triggers with 2.5 < $p_T$ < 4.0 GeV/$c$ and associated charged hadrons with 1.7 < $p_T$ < 2.5 GeV/$c$ in $d$+Au collisions.

$\Delta\phi$ distributions unidentified triggers with 2.5 < $p_T$ < 4.0 GeV/$c$ and associated charged hadrons with 1.7 < $p_T$ < 2.5 GeV/$c$ in $p$+$p$ collisions.

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Azimuthal angle correlations for rapidity separated hadron pairs in d + Au collisions at s(NN)**(1/2) = 200-GeV.

The PHENIX collaboration Adler, S.S. ; Afanasiev, S. ; Aidala, C. ; et al.
Phys.Rev.Lett. 96 (2006) 222301, 2006.
Inspire Record 712584 DOI 10.17182/hepdata.142147

We report on two-particle azimuthal angle correlations between charged hadrons at forward/backward (deuteron/gold going direction) rapidity and charged hadrons at mid-rapidity in deuteron-gold (d+Au) and proton-proton (p+p) collisions at sqrt(s_NN) = 200 GeV. Jet structures are observed in the correlations which we quantify in terms of the conditional yield and angular width of away side partners. The kinematic region studied here samples partons in the gold nucleus carrying nucleon momentum fraction x~0.1 to x~0.01. Within this range, we find no x dependence of the jet structure in d+Au collisions.

6 data tables

Azimuthal angle correlation functions. Note that the y-axis is zero-suppressed on the middle and bottom panels. In the additonal resource, the Gaussian widths from the fits and the signal to background ration integrated over $\pi$ - 1 < $\Delta\phi$ < $\pi$ + 1 are shown.

Conditional yields (CY) shown as a function of trigger particle pseudorapitidy for trigger particle $p_T$ from 2.5 to 4.0 and associated particle $p_T$ from 1.0 to 2.5 GeV/$c$. The additional $\pm$0.037 systematic error on the mid-rapidity $p+p$ point is from jet yield extraction. There is a 1% point-by-point systematical error on all points except central arm triggers. There is also a 10% systematic error for all data points due to the determination of associated particle efficiency. For $p + p$ point, forward and backward trigger are combined, so the results are identical.

$I_{dAu}$ vs. $p_T^{assoc}$ for different centrality, $p_T^{trig}$ and $\eta^{trig}$ bins.

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Saturation of azimuthal anisotropy in Au + Au collisions at s(NN)**(1/2) = 62-GeV - 200-GeV.

The PHENIX collaboration Adler, S.S. ; Afanasiev, S. ; Aidala, C. ; et al.
Phys.Rev.Lett. 94 (2005) 232302, 2005.
Inspire Record 664944 DOI 10.17182/hepdata.141741

New measurements are presented for charged hadron azimuthal correlations at mid-rapidity in Au+Au collisions at sqrt(s_NN) = 62.4 and 200 GeV. They are compared to earlier measurements obtained at sqrt(s_NN) = 130 GeV and in Pb+Pb collisions at sqrt(s_NN) = 17.2 GeV. Sizeable anisotropies are observed with centrality and transverse momentum (p_T) dependence characteristic of elliptic flow (v_2). For a broad range of centralities, the observed magnitudes and trends of the differential anisotropy, v_2(p_T), change very little over the collision energy range sqrt(s_NN) = 62-200 GeV, indicating saturation of the excitation function for v_2 at these energies. Such a saturation may be indicative of the dominance of a very soft equation of state for sqrt(s_NN) = 62-200 GeV.

10 data tables

Assorted-$p_T$ correlation functions (0.65 < $p_{T,ref}$ < 2.5 GeV/$c$) for charged hadrons of 0.5 < $p_T$ < 0.7 GeV/$c$ and 1.0 < $p_T$ < 1.5 obtained in Au+Au collisions at $\sqrt{S_{NN}}$ = 62.4 GeV.

Differential anisotropy $v_2$($p_T$) for charged hadrons in Au + Au collisions at $\sqrt{s_{NN}}$ = 200 GeV obtained via cumulants method

Differential anisotropy $v_2$($p_T$) for charged hadrons in Au + Au collisions at $\sqrt{s_{NN}}$ = 200 GeV obtained via correlation function method

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Nuclear modification factors of phi mesons in d+Au, Cu+Cu and Au+Au collisions at sqrt(S_NN)=200 GeV

The PHENIX collaboration Adare, A. ; Afanasiev, S. ; Aidala, C. ; et al.
Phys.Rev.C 83 (2011) 024909, 2011.
Inspire Record 852260 DOI 10.17182/hepdata.141454

The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) has performed systematic measurements of phi meson production in the K+K- decay channel at midrapidity in p+p, d+Au, Cu+Cu and Au+Au collisions at sqrt(S_NN)=200 GeV. Results are presented on the phi invariant yield and the nuclear modification factor R_AA for Au+Au and Cu+Cu, and R_dA for d+Au collisions, studied as a function of transverse momentum (1&lt;p_T&lt;7 GeV/c) and centrality. In central and mid-central Au+Au collisions, the R_AA of phi exhibits a suppression relative to expectations from binary scaled p+p results. The amount of suppression is smaller than that of the neutral pion and the eta meson in the intermediate p_T range (2--5 GeV/c); whereas at higher p_T the phi, pi^0, and eta show similar suppression. The baryon (protons and anti-protons) excess observed in central Au+Au collisions at intermediate p_T is not observed for the phi meson despite the similar mass of the proton and the phi. This suggests that the excess is linked to the number of constituent quarks rather than the hadron mass. The difference gradually disappears with decreasing centrality and for peripheral collisions the R_AA values for both particles are consistent with binary scaling. Cu+Cu collisions show the same yield and suppression as Au+Au collisions for the same number of N_part. The R_dA of phi shows no evidence for cold nuclear effects within uncertainties.

6 data tables

Invariant $p_T$ spectra of the $\phi$ meson for different centrality bins in Au+Au, Cu+Cu, $d$+Au, and $p$+$p$ collisions at $\sqrt{s_{NN}}$ = 200 GeV.

$R_{AA}$ vs. $p_T$ for $\phi$ in central Au+Au collisions, $R_{AA}$ vs. $p_T$ for $\phi$ and $\pi^0$ in 10-20% mid-central Au+Au collisions, and $R_{AA}$ vs. $p_T$ for $\phi$ and $p$+$\bar{p}$ in 60-92% and for $\pi^0$ in 80-92% peripheral Au+Au collisions. The global uncertainty of ~ 10% related to the $p$+$p$ reference normalization is not shown.

$R_{AA}$ vs. $p_T$ for $\phi$ for 30-40% centrality Au+Au and 0-10% centrality Cu+Cu collisions, and $R_{AA}$ vs. $p_T$ for $\phi$ and $\pi^0$ for 40-50% centrality Au+Au and 10-20% centrality Cu+Cu collisions. The global uncertainty of ~ 10% related to the $p$+$p$ reference normalization is not shown.

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Version 2
Dihadron azimuthal correlations in Au+Au collisions at sqrt(s_NN)=200 GeV

The PHENIX collaboration Adare, A. ; Afanasiev, S. ; Aidala, C. ; et al.
Phys.Rev.C 78 (2008) 014901, 2008.
Inspire Record 778396 DOI 10.17182/hepdata.96764

Azimuthal angle (Delta phi) correlations are presented for a broad range of transverse momentum (0.4 < pT < 10 GeV/c) and centrality (0-92%) selections for charged hadrons from di-jets in Au+Au collisions at sqrt(s_NN) = 200 GeV. With increasing pT, the away-side Delta phi distribution evolves from a broad and relatively flat shape to a concave shape, then to a convex shape. Comparisons to p+p data suggest that the away-side distribution can be divided into a partially suppressed head region centered at Delta phi ~ \pi, and an enhanced shoulder region centered at Delta phi ~ \pi \pm 1:1. The pT spectrum for the associated hadrons in the head region softens toward central collisions. The spectral slope for the shoulder region is independent of centrality and trigger pT . The properties of the near-side distributions are also modified relative to those in p + p collisions, reflected by the broadening of the jet shape in Delta phi and Delta eta, and an enhancement of the per-trigger yield. However, these modifications seem to be limited to pT < 4 GeV/c, above which both the dihadron pair shape and per-trigger yield become similar to p + p collisions. These observations suggest that both the away- and near-side distributions contain a jet fragmentation component which dominates for pT \ge 5GeV and a medium-induced component which is important for pT \le 4 GeV/c. We also quantify the role of jets at intermediate and low pT through the yield of jet-induced pairs in comparison to binary scaled p + p pair yield. The yield of jet-induced pairs is suppressed at high pair proxy energy (sum of the pT magnitudes of the two hadrons) and is enhanced at low pair proxy energy. The former is consistent with jet quenching/ the latter is consistent with the enhancement of soft hadron pairs due to transport of lost energy to lower pT.

116 data tables

The 0-20% Au+Au jet-induced hadron-pair yield $\Delta\phi$ distributions calculated from the per-trigger yield using low-$p_T$ hadrons as triggers and high-$p_T$ hadrons as triggers. Data for 2 - 3 GeV/$c$.

Per-trigger yield versus $\Delta\phi$ for various trigger and partner $p_T$ ($p^a_T \otimes p^b_T$), arranged by increasing pair proxy energy (sum of $p^a_T$ and $p^b_T$), in p + p collisions for 5-10 $\otimes$ 2-3, 4-5 $\otimes$ 4-5, 5-10 $\otimes$ 3-5, and 5-10 $\otimes$ 5-10 GeV/c.

The 0-20% Au+Au jet-induced hadron-pair yield $\Delta\phi$ distributions calculated from the per-trigger yield using low-$p_T$ hadrons as triggers and high-$p_T$ hadrons as triggers. Data for 3 - 4 GeV/$c$.

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High transverse momentum eta meson production in p+p, d+Au and Au+Au collisions at S(NN)**(1/2) = 200-GeV

The PHENIX collaboration Adler, S.S. ; Afanasiev, S. ; Aidala, C. ; et al.
Phys.Rev.C 75 (2007) 024909, 2007.
Inspire Record 731133 DOI 10.17182/hepdata.96498

Inclusive transverse momentum spectra of eta mesons in the range p_T~2-12 GeV/c have been measured at mid-rapidity (|\eta| < 0,35) by the PHENIX experiment at RHIC in p+p, d+Au and Au+Au collisions at sqrt(s_NN) = 200 GeV. The eta mesons are reconstructed through their eta--> \gamma\gamma channel for the three colliding systems as well as through the eta-->pi^0 pi+ pi- decay mode in p+p and d+Au collisions. The nuclear modification factor in d+Au collisions, R_dAu(p_T~1.0-1.1, suggests at most only modest p_T broadening (Cronin enhancement). In central Au+Au reactions, the eta yields are significantly suppressed, with R_AuAu(pT)~0.2. The ratio of eta to pi^0 yields is approximately constant as a function of p_T for the three colliding systems in agreement with the high-p_T world average of R_eta/pi^0 \approx 0.5 in hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions for a wide range of center-of-mass energies [sqrt(s_NN)~3-1800 GeV] as well as, for high scaled momentum x_p, in e+e- annihilations at sqrt(s)=91.2 GeV. These results are consistent with a scenario where high-p_T eta production in nuclear collisions at RHIC is largely unaffected by initial-state effects, but where light-quark mesons (pi^0:eta) are equally suppressed due to final-state interactions of the parent partons in the dense medium produced in Au+Au reactions.

11 data tables

Inelastic cross section measured in p+p at $\sqrt{s}$=200 GeV through $\eta \rightarrow \gamma \gamma$

Inelastic cross section measured in p+p at $\sqrt{s}$=200 GeV through $\eta \rightarrow \pi^{0} \pi^{+} \pi^{-}$

Inelastic cross section measured in d+Au at $\sqrt{s}$=200 GeV through $\eta \rightarrow \gamma \gamma$

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