| 1. |
- Adcox, K, et al.
(författare)
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PHENIX detector overview
- 2003
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 499:2-3, s. 469-479
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Tidskriftsartikel (refereegranskat)abstract
- The PHENIX detector is designed to perform a broad study of A-A, p-A, and p-p collisions to investigate nuclear matter under extreme conditions. A wide variety of probes, sensitive to all timescales, are used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon. Designing for the needs of the heavy-ion and polarized-proton programs has produced a detector with unparalleled capabilities. PHENIX measures electron and muon pairs, photons, and hadrons with excellent energy and momentum resolution. The detector consists of a large number of subsystems that are discussed in other papers in this volume. The overall design parameters of the detector are presented. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 2. |
- Adler, SS, et al.
(författare)
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Bose-Einstein correlations of charged pion pairs in Au+Au collisions at root(NN)-N-s = 200 GeV
- 2004
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Ingår i: Physical Review Letters. - 1079-7114. ; 93:15
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Tidskriftsartikel (refereegranskat)abstract
- Bose-Einstein correlations of identically charged pion pairs were measured by the PHENIX experiment at midrapidity in Au+Au collisions at roots(NN)=200 GeV. The Bertsch-Pratt radius parameters were determined as a function of the transverse momentum of the pair and as a function of the centrality of the collision. Using the standard core-halo partial Coulomb fits, and a new parametrization which constrains the Coulomb fraction as determined from the unlike-sign pion correlation, the ratio R-out/R-side is within 0.8-1.1 for 0.25<<1.2 GeV/c. The centrality dependence of all radii is well described by a linear scaling in N-part(1/3), and R-out/R-side for similar to0.45 GeV/c is approximately constant at unity as a function of centrality.
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| 3. |
- Adler, SS, et al.
(författare)
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Elliptic flow of identified hadrons in Au+Au collisions at root s(NN)=200 GeV
- 2003
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Ingår i: Physical Review Letters. - 1079-7114. ; 91:18: 182301
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Tidskriftsartikel (refereegranskat)abstract
- The anisotropy parameter (v(2)), the second harmonic of the azimuthal particle distribution, has been measured with the PHENIX detector in Au+Au collisions at roots(NN)=200 GeV for identified and inclusive charged particle production at central rapidities (eta<0.35) with respect to the reaction plane defined at high rapidities (eta=3-4 ). We observe that the v(2) of mesons falls below that of (anti)baryons for p(T)>2 GeV/c, in marked contrast to the predictions of a hydrodynamical model. A quark-coalescence model is also investigated.
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| 4. |
- Adler, SS, et al.
(författare)
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J/psi production from proton-proton collisions at root s=200 GeV
- 2004
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Ingår i: Physical Review Letters. - 1079-7114. ; 92:5
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Tidskriftsartikel (refereegranskat)abstract
- J/psi production has been measured in proton-proton collisions at roots=200 GeV over a wide rapidity and transverse momentum range by the PHENIX experiment at the Relativistic Heavy Ion Collider. Distributions of the rapidity and transverse momentum, along with measurements of the mean transverse momentum and total production cross section are presented and compared to available theoretical calculations. The total J/psi cross section is 4.0+/-0.6(stat)+/-0.6(syst)+/-0.4(abs) mub. The mean transverse momentum is 1.80+/-0.23(stat)+/-0.16(syst) GeV/c.
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| 5. |
- Adler, SS, et al.
(författare)
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J/psi production in Au-Au collisions at root s(NN)=200 GeV
- 2004
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 69:1
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Tidskriftsartikel (refereegranskat)abstract
- First results on charm quarkonia production in heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) are presented. The yield of J/psi's measured in the PHENIX experiment via electron-positron decay pairs at midrapidity for Au-Au reactions at roots(NN) = 200 GeV is analyzed as a function of collision centrality. For this analysis we have studied 49.3x10(6) minimum bias Au-Au reactions. We present the J/psi invariant yield dN/dy for peripheral and midcentral reactions. For the most central collisions where we observe no signal above background, we quote 90% confidence level upper limits. We compare these results with our J/psi measurement from proton-proton reactions at the same energy. We find that our measurements are not consistent with models that predict strong enhancement relative to binary collision scaling.
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| 6. |
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| 7. |
- Adler, SS, et al.
(författare)
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Scaling properties of proton and antiproton production in root s(NN)=200 GeV Au+Au collisions
- 2003
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Ingår i: Physical Review Letters. - 1079-7114. ; 91:17: 172301
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Tidskriftsartikel (refereegranskat)abstract
- We report on the yield of protons and antiprotons, as a function of centrality and transverse momentum, in Au+Au collisions at rootS(NN)=200 GeV measured at midrapidity by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider. In central collisions at intermediate transverse momenta (1.5
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| 8. |
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| 9. |
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| 10. |
- Ji, JZ, et al.
(författare)
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Modulation of L-type Ca(2+) channels by distinct domains within SNAP-25
- 2002
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 51:5, s. 1425-1436
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Tidskriftsartikel (refereegranskat)abstract
- Cognate soluble N-ethylmaleimide–sensitive factor attachment protein receptor (SNARE) proteins are now known to associate the secretory vesicle with both the target plasma membrane and Ca2+ channels in order to mediate the sequence of events leading to exocytosis in neurons and neuroendocrine cells. Neuroendocrine cells, particularly insulin-secreting islet β-cells, t-SNARE proteins, 25-kDa synaptosomal-associated protein (SNAP-25), and syntaxin 1A, independently inhibit the L-type Ca2+ channel (LCa). However, when both are present, they actually exhibit stimulatory actions on the LCa. This suggests that the positive regulation of the LCa is conferred by a multi-SNARE protein complex. We hypothesized an alternate explanation, which is that each of these SNARE proteins possess distinct inhibitory and stimulatory domains that act on the LCa. These SNARE proteins were recently shown to bind the Lc753–893 domain corresponding to the II and III intracellular loop of the α1C subunit of the LCa. In this study, using patch-clamp methods on primary pancreatic β-cells and insulinoma HIT-T15 cells, we examined the functional interactions of the botulinum neurotoxin A (BoNT/A) cleavage products of SNAP-25, including NH2-terminal (1–197 amino acids) and COOH-terminal (amino acid 198–206) domains, on the LCa, particularly at the Lc753–893 domain. Intracellular application of SNAP-251–206 in primary β-cells decreased LCa currents by ∼15%. The reduction in LCa currents was counteracted by coapplication of Lc753–893. Overexpression or injection of wild-type SNAP-25 in HIT cells reduced LCa currents by ∼30%, and this inhibition was also blocked by the recombinant Lc753–893 peptide. Expression of BoNT/A surprisingly caused an even greater reduction of LCa currents (by 41%), suggesting that the BoNT/A cleavage products of SNAP-25 might possess distinct inhibitory and positive regulatory domains. Indeed, expression of SNAP-251–197 increased LCa currents (by 19% at 10 mV), and these effects were blocked by the Lc753–893 peptide. In contrast, injection of SNAP-25198–206 peptide into untransfected cells inhibited LCa currents (by 47%), and more remarkably, these inhibitory effects dominated over the stimulatory effects of SNAP-251–197 overexpression (by 34%). Therefore, the SNARE protein SNAP-25 possesses distinct inhibitory and stimulatory domains that act on the LCa. The COOH-terminal 197–206 domain of SNAP-25, whose inhibitory actions dominate over the opposing stimulatory NH2-terminal domain, likely confers the inhibitory actions of SNAP-25 on the LCa. We postulate that the eventual accelerated proteolysis of SNAP-25 brought about by BoNT/A cleavage allows the relatively intact NH2-terminal SNAP-25 domain to assert its stimulatory action on the LCa to increase Ca2+ influx, and this could in part explain the observed weak or inconsistent inhibitory effects of BoNT/A on insulin secretion. The present study suggests that distinct domains within SNAP-25 modulate LC subtype Ca2+ channel activity in both primary β-cells and insulinoma HIT-T15 cells.
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