We introduced a novel negative multiple pulse poling (NMP) method for uniform device fabrication of quasi-phase matching using an in-situ visualization system. Diffraction pattern analysis showed the duty ratio of 0.4...
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ISBN:
(纸本)9780977565771
We introduced a novel negative multiple pulse poling (NMP) method for uniform device fabrication of quasi-phase matching using an in-situ visualization system. Diffraction pattern analysis showed the duty ratio of 0.42, and the standard deviation of 0.02 which means the uniform quality of the whole poled area.
The PHENIX experiment has measured electrons and positrons at midrapidity from the decays of hadrons containing charm and bottom quarks produced in d+Au and p+p collisions at sNN=200 GeV in the transverse-momentum ra...
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The PHENIX experiment has measured electrons and positrons at midrapidity from the decays of hadrons containing charm and bottom quarks produced in d+Au and p+p collisions at sNN=200 GeV in the transverse-momentum range 0.85≤pTe≤8.5 GeV/c. In central d+Au collisions, the nuclear modification factor RdA at 1.5nuclear-matter effects on light- and heavy-flavor mesons could contribute to the observed differences between the π0 and heavy-flavor-electron nuclear modification factors RAA.
We show that particle species dependence of enhanced hadron production at intermediate transverse momentum (pT) for d+Au collisions at RHIC can be understood in terms of the hadronization from string fragmentation and...
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We show that particle species dependence of enhanced hadron production at intermediate transverse momentum (pT) for d+Au collisions at RHIC can be understood in terms of the hadronization from string fragmentation and the subsequent hadronic rescatterings in the final state. A multiphase transport model (AMPT) with two different hadronization mechanisms, string fragmentation or parton coalescence, is used in our study. When the hadrons are formed from string fragmentation, the subsequent hadronic rescatterings will result in particle mass dependence of the nuclear modification factor RCP, which is consistent with the present experimental data. On the other hand, in the framework of parton coalescence, the mass dependence disappears and the strangeness plays an important role in hadron production.
A process, continuous wrapping tantalum barrier, has been developed and investigated in order to reduce the manufacturing cost. By avoiding inserting expensive tantalum tube, a long sheet barrier was directly used to ...
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A process, continuous wrapping tantalum barrier, has been developed and investigated in order to reduce the manufacturing cost. By avoiding inserting expensive tantalum tube, a long sheet barrier was directly used to wrap a prior restack. In this work, a tantalum barrier with 20 % overlap was wrapped onto sub-elements. Then 18-filament Nb 3 Sn plus 1 copper core restack billet was successfully drawn down and extruded into round wire as thin as a diameter of 0.84 mm. The longitudinal and cross-sectional images revealed most of barriers were continuous and intact. However, further experiments are needed to optimize the process in order to keep the all barriers continuous and intact after manufacturing.
A highly sensitive temperature sensor based on a side-hole fiber filled with indium was proposed and its optical characteristics were experimentally demonstrated. The temperature sensitivity of the sensor was estimate...
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ISBN:
(纸本)9781557529312
A highly sensitive temperature sensor based on a side-hole fiber filled with indium was proposed and its optical characteristics were experimentally demonstrated. The temperature sensitivity of the sensor was estimated to be dλ/dT=-7.5 nm/°C.
The second Fourier component v2 of the azimuthal anisotropy with respect to the reaction plane is measured for direct photons at midrapidity and transverse momentum (pT) of 1–12 GeV/c in Au+Au collisions at sNN=200 ...
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The second Fourier component v2 of the azimuthal anisotropy with respect to the reaction plane is measured for direct photons at midrapidity and transverse momentum (pT) of 1–12 GeV/c in Au+Au collisions at sNN=200 GeV. Previous measurements of this quantity for hadrons with pT<6 GeV/c indicate that the medium behaves like a nearly perfect fluid, while for pT>6 GeV/c a reduced anisotropy is interpreted in terms of a path-length dependence for parton energy loss. In this measurement with the PHENIX detector at the Relativistic Heavy Ion Collider we find that for pT>4 GeV/c the anisotropy for direct photons is consistent with zero, which is as expected if the dominant source of direct photons is initial hard scattering. However, in the pT<4 GeV/c region dominated by thermal photons, we find a substantial direct-photon v2 comparable to that of hadrons, whereas model calculations for thermal photons in this kinematic region underpredict the observed v2.
We report the measurement of direct photons at midrapidity in Au+Au collisions at sNN=200 GeV. The direct photon signal was extracted for the transverse momentum range of 4 GeV/c<pT<22 GeV/c, using a statisti...
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We report the measurement of direct photons at midrapidity in Au+Au collisions at sNN=200 GeV. The direct photon signal was extracted for the transverse momentum range of 4 GeV/cnuclear modification factor RAA was calculated as a function of pT for different Au+Au collision centralities using the measured p+p direct photon spectrum and compared to theoretical predictions. RAA was found to be consistent with unity for all centralities over the entire measured pT range. Theoretical models that account for modifications of initial direct photon production due to modified parton distribution functions in Au and the different isospin composition of the nuclei predict a modest change of RAA from unity. They are consistent with the data. Models with compensating effects of the quark-gluon plasma on high-energy photons, such as suppression of jet-fragmentation photons and induced-photon bremsstrahlung from partons traversing the medium, are also consistent with this measurement.
Measurements of the anisotropy parameter v2 of identified hadrons (pions, kaons, and protons) as a function of centrality, transverse momentum pT, and transverse kinetic energy KET at midrapidity (|η|<0.35) in Au ...
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Measurements of the anisotropy parameter v2 of identified hadrons (pions, kaons, and protons) as a function of centrality, transverse momentum pT, and transverse kinetic energy KET at midrapidity (|η|<0.35) in Au + Au collisions at sNN=200 GeV are presented. Pions and protons are identified up to pT= 6 GeV/c, and kaons up to pT= 4 GeV/c, by combining information from time-of-flight and aerogel Čerenkov detectors in the PHENIX Experiment. The scaling of v2 with the number of valence quarks (nq) has been studied in different centrality bins as a function of transverse momentum and transverse kinetic energy. A deviation from previously observed quark-number scaling is observed at large values of KET/nq in noncentral Au + Au collisions (20–60%), but this scaling remains valid in central collisions (0–10%).
We report on charmonium measurements [J/ψ (1S), ψ′ (2S), and χc (1P)] in p+p collisions at s=200 GeV. We find that the fraction of J/ψ coming from the feed-down decay of ψ′ and χc in the midrapidity region (|...
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We report on charmonium measurements [J/ψ (1S), ψ′ (2S), and χc (1P)] in p+p collisions at s=200 GeV. We find that the fraction of J/ψ coming from the feed-down decay of ψ′ and χc in the midrapidity region (|y|<0.35) is 9.6±2.4% and 32±9%, respectively. We also present the pT and rapidity dependencies of the J/ψ yield measured via dielectron decay at midrapidity (|y|<0.35) and via dimuon decay at forward rapidity (1.2<|y|<2.2). The statistical precision greatly exceeds that reported in our previous publication [Phys. Rev. Lett. 98, 232002 (2007)]. The new results are compared with other experiments and discussed in the context of current charmonium production models.
Background: Heavy-flavor production in p + p collisions is a good test of perturbative-quantum-chromodynamics (pQCD) calculations. Modification of heavy-flavor production in heavy-ion collisions relative to binary-col...
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Background: Heavy-flavor production in p + p collisions is a good test of perturbative-quantum-chromodynamics (pQCD) calculations. Modification of heavy-flavor production in heavy-ion collisions relative to binary-collision scaling from p + p results, quantified with the nuclear-modification factor (RAA), provides information on both cold- and hot-nuclear-matter effects. Midrapidity heavy-flavor RAA measurements at the Relativistic Heavy Ion Collider have challenged parton-energy-loss models and resulted in upper limits on the viscosity-entropy ratio that are near the quantum lower bound. Such measurements have not been made in the forward-rapidity region.
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