期刊：
Modern Physics Letters A,2007年22(19):1381-1389 ISSN：0217-7323
通讯作者：
Xiang, W. C.
作者机构：
[Zhou, D. C.; Xiang, W. C.] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;[Xiang, W. C.] Univ Bielefeld, Dept Phys, D-33501 Bielefeld, Germany.
通讯机构：
[Xiang, W. C.] C;Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
关键词：
Heavy ion collision;parton energy loss;factorization
作者机构：
[Zhou, D. C.] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Zhou, D. C.] C;Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
会议名称：
19th International Conference on Ultra-Relativistic Necleus-Nucleus Collisions
会议时间：
NOV 14-20, 2006
会议地点：
Shanghai, PEOPLES R CHINA
会议主办单位：
Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
摘要：
We discuss the physics requirements of the ALICE PHOton Spectrometer (PHOS) and describe its main characteristics and structure. The beam test results of the PHOS show that PHOS is capable of detecting photons efficiently up to 100 GeV/c in ALICE.
期刊：
International Journal of Modern Physics E,2007年16(7-8):2123-2129 ISSN：0218-3013
通讯作者：
Zhang, X. M.
作者机构：
[Zhou, D. C.; Zhang, X. M.; Xiang, W. C.] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Zhang, X. M.] C;Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
会议名称：
19th International Conference on Ultra-Relativistic Necleus-Nucleus Collisions
会议时间：
NOV 14-20, 2006
会议地点：
Shanghai, PEOPLES R CHINA
会议主办单位：
[Zhang, X. M.;Zhou, D. C.;Xiang, W. C.] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
摘要：
We demonstrate by using Wiedemann's gluon radiative spectrum that heavy quark radiative energy loss spectrum can be factorized as the light quark radiative energy loss spectrum times a dead cone factor in the absence of medium effect. The availability of factorial approach with a dead cone approximation in medium is studied by Djordjevic-Gyulassy (D-G) and GLV (M.Gyulassy, P.Levai and I.Vitev) formulas. The numerical results show that the factorial method with a dead cone approximation is more suitable for charm quarks than bottom quarks at both RHIC andLHC energies.
作者机构：
[Ding Heng-Tong] Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;Museo Stor Fis, Rome, Italy.;Ctr Study & Ricerche Enrico Fermi, Rome, Italy.
通讯机构：
[Ding Heng-Tong] H;Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
关键词：
Energy Loss;Production
摘要：
Based on the HVQMNR model of heavy flavour production and the BDMPS approach on parton energy loss, we have investigated the energy loss effect of charm quark on (di)muon spectra in forward rapidity region covered by ALICE forward muon spectrometer in Pb+Pb collisions at c.m. energy snn1/2 = 5.5 TeV. Results show that (di)muon spectra are very sensitive to the charm quark energy loss and can provide valuable information on the energy loss of heavy flavours.
作者机构：
[Zhou, DC; Liu, J; Mao, YX; Xiang, WC] Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Zhou, DC] H;Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
关键词：
high energy heavy-ion collision;light-cone path integral approach;induced gluon radiation;heavy quark energy loss.
摘要：
Induced gluon radiation and energy loss of heavy quark in hot and dense QCD media are discussed. Using the light-cone path integral approach, an analytical formula of the energy loss of heavy quark is derived. The results show that the quark energy loss obviously depends on the mass of quark, i. e. a remarkable suppression occurs in the case of heavy quark comparing to a light one. The radiative energy loss of energetic quark is proportional to L 2, where L is the length of the medium. The dependence of energy loss on L 2 turns to L with decreasing quark energy.
作者机构：
[Zhou, Dai-Cui; Yin, Zhong-Bao] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Yin, Zhong-Bao] C;Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
关键词：
ALICE PHOS;front-end electronics;physics performance
摘要：
The physics requirements and the main characteristics of the current design of the front-end electronics (FEE) of ALICE photon spectrometer (PHOS) are discussed. A dedicated test facility has been established in Wuhan to evaluate the physics performance of PHOS FEE. The test results show that the current FEE prototype has met the physics requirements of the PHOS detector.
关键词：
photon detector readout;photodiode;APD;configurable front end electronics;discrete low-noise shaper;dynamic range;timing resolution;altro ADC
摘要：
We describe the principles and measured performance of custom configurable 32-channel shaper/digitizer Front End Electronics (FEE) cards with 14-bit dynamic range for gain-adjustable photon detectors. The electronics has been designed for the PHOS calorimeter of ALICE with avalanche photodiode (APD) readout operated at -25 degrees C ambient temperature and a signal shaping time of 1 mu s. The electronics has also been adopted by the EMCal detector of ALICE with the same APD readout, but operated at an ambient temperature of +20 degrees C and with a shaping time of 100 us. The CR-RC2 signal shapers on the FEE cards are implemented in discrete logic on a 10-layer board with two shaper sections for each input channel. The two shaper sections with gain ratio of 16:1 are digitized by 10-bit ADCs and provide an effective dynamic range of 14 bits. Gain adjustment for each individual APD is available through 32 bias voltage control registers of 10-bit range. The fixed gains and shaping times of the pole-zero compensated shapers are defined prior to FEE production by the values of a few R and C components. For trigger purposes, "fast OR" outputs with 12-bit dynamic range are available. FPGA based slave logic, combined with a USB processor supports a variety of remote control and monitoring features, including APD gain calibration. The measurements presented here for APDs at -25 degrees C ambient temperature and 1 mu s shaping time achieve an average RMS noise level of 0.25 ADC counts or 290 electrons. The linearity over the dynamic range is better than 1%, as is the uniformity of shaping time and gain over 32 channels. Due to the excellent correspondence of the output pulse shape with offline fit, a differential timing resolution of less than 1.5ns between channels has been achieved at ca. 2 GeV, i.e. at 1.5% of the dynamic range of PHOS. (c) 2006 Elsevier B.V. All rights reserved.
作者机构：
[Zhou, DC; Xiang, WC; Ding, HT] Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Xiang, WC] H;Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
关键词：
重离子碰撞;放射性能量损失;重夸克;死锥效应
摘要：
The lowest-order heavy quark radiative energy loss has been analysed to quantify the dead cone effect. The medium-induced gluon radiation is found to fill the dead cone, it is reduced at large gluon energies compared to the radiation of light quarks. We calculate the radiative energy loss of heavy quarks in the condition of dead cone effect. It is found that the radiative energy loss with dead cone effect is smaller than that without the dead cone effect.
作者机构：
[Peng, R] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;Shanghai Univ, Dept Phys, Shanghai 200436, Peoples R China.;Chinese Acad Sci, Shanghai Inst Nucl Res, Shanghai 201800, Peoples R China.
通讯机构：
[Peng, R] C;Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
关键词：
重子作用;金-金碰撞;相对论重子碰撞;核子分布;反核子分布
摘要：
We predict that χcJ mesons at low transverse momentum in the central rapidity region are almost dissociated by nucleons and antinucleons in hadronic matter produced in central Au+Au collisions at relativistic high-ion collider (RHIC) energies (sNN)1/2 = 130 and 200 GeV. In the calculations the nucleon and antinucleon distributions in hadronic matter are results of evolution from their freeze-out distributions which well fit the experimental transverse momentum spectra of proton and antiproton.
摘要：
Nucleon-χcJ dissociation cross sections obtained in the quark exchange mechanism are applied to study χcJ suppression in hadronic matter created in central Pb+Pb and S+Pb collisions.Thermal average of the product of the dissociation cross section and the relative velocity of nucleon and χcJ is discussed.The survival probabilities of χcJ in the central Pb+Pb and S+Pb collisions show that the suppression caused by the collisions with nucleons and antinucleons is appreciable.
