| 1. |
- Adare, A., et al.
(author)
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Measurement of neutral mesons in p plus p collisions at root s=200 GeV and scaling properties of hadron production
- 2011
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In: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 83:5
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Journal article (peer-reviewed)abstract
- The PHENIX experiment at the Relativistic Heavy Ion Collider has measured the invariant differential cross section for production of K-S(0), omega, eta', and phi mesons in p + p collisions at root s 200 GeV. Measurements of omega and phi production in different decay channels give consistent results. New results for the omega are in agreement with previously published data and extend the measured p(T) coverage. The spectral shapes of all hadron transverse momentum distributions measured by PHENIX are well described by a Tsallis distribution functional form with only two parameters, n and T, determining the high-p(T) and characterizing the low-p(T) regions of the spectra, respectively. The values of these parameters are very similar for all analyzed meson spectra, but with a lower parameter T extracted for protons. The integrated invariant cross sections calculated from the fitted distributions are found to be consistent with existing measurements and with statistical model predictions.
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| 2. |
- Adare, A, et al.
(author)
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PHENIX Collaboration
- 2017
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In: Nuclear Physics A. - 0375-9474. ; 967, s. 996-1003
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Journal article (peer-reviewed)
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| 3. |
- Adare, A., et al.
(author)
-
J/psi production versus transverse momentum and rapidity in p+p collisions at root s=200 GeV
- 2007
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In: Physical Review Letters. - 1079-7114. ; 98:23
-
Journal article (peer-reviewed)abstract
- J/psi production in p+p collisions at root s=200 GeV has been measured by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider over a rapidity range of -2.2 < y < 2.2 and a transverse momentum range of 0 < p(T)< 9 GeV/c. The size of the present data set allows a detailed measurement of both the p(T) and the rapidity distributions and is sufficient to constrain production models. The total cross section times the branching ratio is B-ll sigma(J/psi)(pp)=178 +/- 3(stat)+/- 53(sys)+/- 18(norm) nb.
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| 4. |
- Adare, A, et al.
(author)
-
Measurement of the relative yields of ψ(2S) to ψ(1S) mesons produced at forward and backward rapidity in p+p, p+Al, p+Au, and He 3 +Au collisions at s NN =200 GeV
- 2017
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In: Physical Review C: covering nuclear physics. - 2469-9985. ; 95:3
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Journal article (peer-reviewed)abstract
- The PHENIX Collaboration has measured the ratio of the yields of ψ(2S) to ψ(1S) mesons produced in p+p, p+Al, p+Au, and He3+Au collisions at sNN=200 GeV over the forward and backward rapidity intervals 1.2<|y|<2.2. We find that the ratio in p+p collisions is consistent with measurements at other collision energies. In collisions with nuclei, we find that in the forward (p-going or He3-going) direction, the relative yield of ψ(2S) mesons to ψ(1S) mesons is consistent with the value measured in p+p collisions. However, in the backward (nucleus-going) direction, the ψ(2S) meson is preferentially suppressed by a factor of ∼2. This suppression is attributed in some models to the breakup of the weakly bound ψ(2S) meson through final-state interactions with comoving particles, which have a higher density in the nucleus-going direction. These breakup effects may compete with color screening in a deconfined quark-gluon plasma to produce sequential suppression of excited quarkonia states.
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| 5. |
- Adare, A., et al.
(author)
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Nuclear matter effects on J/psi production in asymmetric Cu plus Au collisions at root S-NN=200 GeV
- 2014
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In: Physical Review C (Nuclear Physics). - 0556-2813. ; 90:6
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Journal article (peer-reviewed)abstract
- We report on J/psi production from asymmetric Cu + Au heavy-ion collisions at root S-NN = 200 GeV at the Relativistic Heavy Ion Collider at both forward (Cu-going direction) and backward (Au-going direction) rapidities. The nuclear modification of J/psi yields in Cu + Au collisions in the Au-going direction is found to be comparable to that inAu + Au collisions when plotted as a function of the number of participating nucleons. In the Cu-going direction, J/psi production shows a stronger suppression. This difference is comparable in magnitude and has the same sign as the difference expected from shadowing effects due to stronger low-x gluon suppression in the larger Au nucleus.
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| 6. |
- Adare, A., et al.
(author)
-
J/psi production versus centrality, transverse momentum, and rapidity in Au+Au collisions at root S(NN) = 200 GeV
- 2007
-
In: Physical Review Letters. - 1079-7114. ; 98:23
-
Journal article (peer-reviewed)abstract
- The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured J/psi production for rapidities -2.2 < y < 2.2 in Au+Au collisions at root s(NN)=200 GeV. The J/psi invariant yield and nuclear modification factor R-AA as a function of centrality, transverse momentum, and rapidity are reported. A suppression of J/psi relative to binary collision scaling of proton-proton reaction yields is observed. Models which describe the lower energy J/psi data at the CERN Super Proton Synchrotron invoking only J/psi destruction based on the local medium density predict a significantly larger suppression at RHIC and more suppression at midrapidity than at forward rapidity. Both trends are contradicted by our data.
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| 7. |
- Adare, A, et al.
(author)
-
Measurements of double-helicity asymmetries in inclusive J /ψ production in longitudinally polarized p+p collisions at s =510 GeV
- 2016
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In: Physical Review D - Particles, Fields, Gravitation and Cosmology. - 1550-2368. ; 94:11
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Journal article (peer-reviewed)abstract
- We report the double-helicity asymmetry, ALLJ/ψ, in inclusive J/ψ production at forward rapidity as a function of transverse momentum pT and rapidity |y|. The data analyzed were taken during s=510 GeV longitudinally polarized p+p collisions at the Relativistic Heavy Ion Collider in the 2013 run using the PHENIX detector. At this collision energy, J/ψ particles are predominantly produced through gluon-gluon scatterings, thus ALLJ/ψ is sensitive to the gluon polarization inside the proton. We measured ALLJ/ψ by detecting the decay daughter muon pairs μ+μ- within the PHENIX muon spectrometers in the rapidity range 1.2
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| 8. |
- Adare, A., et al.
(author)
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Cross section and double helicity asymmetry for eta mesons and their comparison to pi(0) production in p plus p collisions at root s=200 GeV
- 2011
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In: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 83:3
-
Journal article (peer-reviewed)abstract
- Measurements of double-helicity asymmetries in inclusive hadron production in polarized p + p collisions are sensitive to helicity-dependent parton distribution functions, in particular, to the gluon helicity distribution, Delta g. This study focuses on the extraction of the double-helicity asymmetry in eta production ((p) over right arrow + (p) over right arrow -> eta + X), the eta cross section, and the eta/pi(0) cross section ratio. The cross section and ratio measurements provide essential input for the extraction of fragmentation functions that are needed to access the helicity-dependent parton distribution functions.
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| 9. |
- Adare, A., et al.
(author)
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Dihadron azimuthal correlations in Au+Au collisions at root s(NN)=200 GeV
- 2008
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In: Physical Review C (Nuclear Physics). - 0556-2813. ; 78:1
-
Journal article (peer-reviewed)abstract
- Azimuthal angle (Delta phi) correlations are presented for a broad range of transverse momentum (0.4 < p(T) < 10 GeV/c) and centrality (0-92%) selections for charged hadrons from dijets in Au+Au collisions at root s(NN) = 200 GeV. With increasing p(T), the away-side Delta phi distribution evolves from a broad and relatively flat shape to a concave shape, then to a convex shape. Comparisons with p + p data suggest that the away-side distribution can be divided into a partially suppressed "head" region centered at Delta phi similar to pi, and an enhanced "shoulder" region centered at Delta phi similar to pi +/- 1.1. The p(T) 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 p(T). 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 p(T)less than or similar to 4 GeV/c, above which both the hadron 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 p(T) greater than or similar to 5 GeV/c and a medium-induced component which is important for p(T) less than or similar to 4 GeV/c. We also quantify the role of jets at intermediate and low p(T) through the yield of jet-induced pairs in comparison with binary scaled p + p pair yield. The yield of jet-induced pairs is suppressed at high pair proxy energy (sum of the p(T) 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 p(T).
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| 10. |
- Adare, A., et al.
(author)
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Inclusive double-helicity asymmetries in neutral-pion and eta-meson production in + collisions at root s=200 GeV
- 2014
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In: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 90:1
-
Journal article (peer-reviewed)abstract
- Results are presented from data recorded in 2009 by the PHENIX experiment at the Relativistic Heavy Ion Collider for the double-longitudinal spin asymmetry, A(LL), for pi(0) and eta production in root s = 200 GeV polarized p + p collisions. Comparison of the pi(0) results with different theory expectations based on fits of other published data showed a preference for small positive values of gluon polarization, Delta G, in the proton in the probed Bjorken x range. The effect of adding the new 2009 pi(0) data to a recent global analysis of polarized scattering data is also shown, resulting in a best fit Delta G(DSSV)([0.05,0.2]) = 0.06(-0.15)(+0.11) in the range 0.05 < x < 0.2, with the uncertainty at Delta chi(2) = 9 when considering only statistical experimental uncertainties. Shifting the PHENIX data points by their systematic uncertainty leads to a variation of the best-fit value of Delta G(DSSV)([0.05,0.2]) between 0.02 and 0.12, demonstrating the need for full treatment of the experimental systematic uncertainties in future global analyses.
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