摘要：
The PHOS level-0 trigger provides a minimum bias trigger for p-p collisions and information for a level-1 trigger at both p-p and Pb-Pb collisions. There are two level-0 trigger generating algorithms under consideration: the Direct Comparison algorithm and the Weighted Sum algorithm. In order to study trigger algorithms via simulation, a simplified equivalent model is extracted from the trigger electronics to derive the waveform function of the Analog-or signal as input to the trigger algorithms. Simulations shown that the Weighted Sum algorithm can achieve higher trigger efficiency and provide more precise single channel energy information than the direct compare algorithm. An energy resolution of 9.75 MeV can be achieved with the Weighted Sum algorithm at a sampling rate of 40 Msps (mega samples per second) at 1 GeV. The timing performance at a sampling rate of 40 Msps with the Weighted Sum algorithm is better than that at a sampling rate of 20 Msps with both algorithms. The level-0 trigger can be delivered to ALICE CTP within 800 ns with a timing uncertainty of 2 LHC bunch crossing cycles. (C) 2010 Elsevier B.V. All rights reserved.
作者：
Yin, Z. B.*;Liu, L. J.;Muller, H.;Rohrich, D.;Sibiryak, I.;...
期刊：
Journal of Physics: Conference Series,2011年293(1) ISSN：1742-6588
通讯作者：
Yin, Z. B.
作者机构：
[Zhang, F.; Yin, Z. B.; Wang, Y. P.; Wang, D.; Zhou, D. C.] Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Yin, Z. B.] H;Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
会议名称：
14th International Conference on Calorimetry in High Energy Physics (CALOR 2010)
会议时间：
MAY 10-14, 2010
会议地点：
Inst High Energy Phys, Beijing, PEOPLES R CHINA
会议主办单位：
Inst High Energy Phys
会议论文集名称：
Journal of Physics Conference Series
摘要：
The photon spectrometer (PHOS) in the ALICE experiment at LHC is a PbWO<inf>4</inf> crystal based electromagnetic calorimeter, dedicated to measuring photons, π°'s and η's over a broad pT range from about 100 MeV/c to 100 GeV/c with the best possible energy and position resolution. The front-end electronics of the PHOS is thus required to cover a large dynamic range, to achieve a timing resolution better than ∼2 ns in order to discriminate against 1-2 GeV/c (anti-)neutrons, and to provide high pT trigger to select rare high pT events. In this paper, we present the full PHOS readout system, including the avalanche photo-diode, the low noise charge sensitive preamplifier, the 32 channel front-end electronics card, the trigger region unit and the trigger OR module. Results from PHOS commissioning with beam particles and cosmic rays will also be presented to address the performance of the PHOS readout electronics.
作者：
H-T Ding;Z Conesa del Valle;A Dainese;D C Zhou
作者机构：
Institute of Particle Physics, Huazhong Normal University, Wuhan 430079, People's Republic of China;LLR (CNRS/IN2P3-Ecole Polytechnique) Palaiseau, France;INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Padova), Italy;Subatech (CNRS/IN2P3-Ecole des Mines-Université de Nantes) Nantes, France
会议名称：
SQM2008：International Conference on Strangeness in Quark Matter(2008奇异夸克物质国际会议)
会议时间：
2008-10-06
会议地点：
北京
会议论文集名称：
SQM2008：International Conference on Strangeness in Quark Matter(2008奇异夸克物质国际会议)论文集
摘要：
Based on Conesa del Valle et al (2008 Phys. Lett. B 663 202), we present the results for the nuclear modification factors Raa and RCp of the high transverse momentum ( 5 < pt < 60 GeV/c ) distribution of muons in Pb-Pb collisions at LHC energies, in which two pseudo-rapidity ranges covered by the LHC experiments, |η| < 2.5 and 2.5 < η < 4, are investigated. Heavy-quark energy loss is taken into account by mass-dependent BDMPS quenching weights. Muons from semi-leptonic decays of heavy quarks (c and b) and from leptonic decays of weak gauge bosons (W and Z) are the main contributions to the muon pt distribution above a few GeV/c. The muons from W and Z, that dominates the high px, can be used as a medium-blind reference to observe the medium-induced suppression of beauty quarks.
作者机构：
[del Valle, Z. Conesa; Garcia, G. Martinez] Univ Nantes, Ecole Mines, Subatech CNRS IN2P3, Nantes, France.;[Dainese, A.] Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Padua, Italy.;[Zhou, D. C.; Ding, H. -T.] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Garcia, G. Martinez] U;Univ Nantes, Ecole Mines, Subatech CNRS IN2P3, Nantes, France.
关键词：
Heavy quarks;Muons;Quark-gluon plasma;Relativistic heavy-ion collisions;Weak gauge bosons
摘要：
We study the nuclear modification factors R-AA and R-CP of the high transverse momentum (5 < p(t) < 60 GeV/c) distribution of muons in Pb-Pb collisions at LHC energies. We consider two pseudo-rapidity ranges covered by the LHC experiments: |eta| < 2.5 and 2.5 < eta < 4. Muons from semi-leptonic decays of heavy quarks (c and b) and from leptonic decays of weak gauge bosons (W and Z) are the main contributions to the muon p(t) distribution above a few GeV/c. We compute the heavy quark contributions using available pQCD-based programs. We include the nuclear shadowing modification of the parton distribution functions and the in-medium radiative energy loss for heavy quarks, using the mass-dependent BDMPS quenching weights. Muons from W and Z leptonic decays, that dominate the yield at high p(t), can be used as a medium-blind reference to observe the medium-induced suppression of beauty quarks. (C) 2008 Elsevier B.V. All rights reserved.
作者：
H-T Ding;Z Conesa del Valle;A Dainese;D C Zhou
作者机构：
Institute of Particle Physics, Huazhong Normal University, Wuhan 430079, People's Republic of China;LLR (CNRS/IN2P3-Ecole Polytechnique) Palaiseau, France;INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Padova), Italy;Subatech (CNRS/IN2P3-Ecole des Mines-Université de Nantes) Nantes, France
会议名称：
SQM2008：International Conference on Strangeness in Quark Matter(2008奇异夸克物质国际会议)
会议时间：
2008-10-06
会议地点：
北京
会议论文集名称：
SQM2008：International Conference on Strangeness in Quark Matter(2008奇异夸克物质国际会议)论文集
摘要：
Based on Conesa del Valle et al (2008 Phys. Lett. B 663 202), we present the results for the nuclear modification factors Raa and RCp of the high transverse momentum ( 5 < pt < 60 GeV/c ) distribution of muons in Pb-Pb collisions at LHC energies, in which two pseudo-rapidity ranges covered by the LHC experiments, |η| < 2.5 and 2.5 < η < 4, are investigated. Heavy-quark energy loss is taken into account by mass-dependent BDMPS quenching weights. Muons from semi-leptonic decays of heavy quarks (c and b) and from leptonic decays of weak gauge bosons (W and Z) are the main contributions to the muon pt distribution above a few GeV/c. The muons from W and Z, that dominates the high px, can be used as a medium-blind reference to observe the medium-induced suppression of beauty quarks.
作者：
Jie Liu;Yaxian Mao;Wenchang Xiang;Daicui Zhou*
期刊：
科学通报(英文版),2006年51(2):139-142 ISSN：2095-9273
通讯作者：
Daicui Zhou
作者机构：
[Mao Y.; Liu J.; Zhou D.; Xiang W.] Institute of Particle Physics, Huazhong Normal University, Wuhan 430079, China
通讯机构：
[Daicui Zhou] I;Institute of Particle Physics, Huazhong Normal University, Wuhan, China
关键词：
Heavy quark energy loss;High energy heavy-ion collision;Induced gluon radiation;Light-cone path integral approach
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：
Oak Ridge Natl Lab, Dept Phys, Oak Ridge, TN 37831 USA.;Acad Sinica, Shanghai Inst Nucl Res, Div Nucl Phys, Shanghai 201800, Peoples R China.;Hua Zhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;[Xu, XM] Oak Ridge Natl Lab, Dept Phys, Bldg 6011,MS-6373,POB 2008, Oak Ridge, TN 37831 USA.
通讯机构：
[Xu, XM] O;Oak Ridge Natl Lab, Dept Phys, Bldg 6011,MS-6373,POB 2008, Oak Ridge, TN 37831 USA.
关键词：
charmonium dissociation cross sections;proton-nucleus reactions;J/psi,psi ' and chi(c) suppressions
摘要：
Charmonium dissociations by nucleons are first studied from a quark-quark potential in combination with quark exchange mechanism. Wave functions of nucleons and charmed baryons involved in dissociation reactions result from a fit to mass splittings of baryons with spins and 3/2. Transverse momentum and x(F) distributions of prompt J/psi produced in 800 GeV/c p-Be collisions are calculated by using NRQCD dsigma/d (t) over cap for parton-parton scatterings and taking into account initial transverse-momentum distributions of partons inside nucleons. We emphasize that the new dissociation cross sections of J/psi, psi' and chi(cJ) give rise to remarkable differences of J/psi, psi' and chi(c) suppressions at large negative x(F) in p-W collisions at root(s)NN = 38.8 and 41.6 GeV and p-Au collisions at root(s)NN = 130 GeV. (C) 2002 Elsevier Science B.V. All rights reserved.
摘要：
Scaled factorial moment analysis for the multiplicity distribu- tions of shower particles in the pseudorapidity phase space has been done. An evidence for the presence of dynamical uctuations has been shown for the non-peripheral interactions of28Si+Ag(Br) at 14.6 A GeV/c and 4.5 A GeV/c.The results have been compared with the values obtained from data sample calculated by cascade-evaporation model.
作者机构：
[Wu, Tao; Zhou, Dai-Cui] Institute of Particle Physics, Huazhong Normal University, Wuhan 430079, China
通讯机构：
[Wu, T.] I;Institute of Particle Physics, , Wuhan 430079, China
摘要：
Multiplicity distributions of negative, binomial distribution (NBD) and modified NBD are obtained from a birth process model with an immigration. The ratio of factorial cumulant moment to factorial moment, i.e., H moment is calculated from different multiplicity distributions of NBD, modified NBD and the three fireball model, which shows an oscillatory behavior when there is a truncation of multiplicity. The oscillation of H moment is related to the common character of the truncated multiplicity distributions.
期刊：
EUROPEAN PHYSICAL JOURNAL A,1999年5(4):429-440 ISSN：1434-6001
通讯作者：
Adamovich, MI
作者机构：
PN Lebedev Phys Inst, Moscow 117924, Russia.;Inst High Energy Phys, Alma Ata, Kazakhstan.;Acad Sinica, Inst High Energy Phys, Beijing, Peoples R China.;Inst Space Sci, Bucharest, Romania.;Panjab Univ, Dept Phys, Chandigarh 160014, India.
摘要：
The experimental data on the interactions of 10.6A GeV gold nuclei in nuclear emulsions are analyzed with particular emphasis of target separation interactions and study of critical exponents. Charged fragment moments, conditional moments as well as two and three - body asymmetries of the fast moving. projectile particles are determined in terms of the total charge remaining bound in the multiply charged projectile fragments. Some differences in the average yields of helium nuclei and heavier fragments are observed, which may be attributed to a target effect. However, two and three-body asymmetries and conditional moments indicate that the breakup mechanism of the projectile seems to be independent of target mass. We looked for evidence of critical point observable in finite nuclei by study the resulting charged fragments distributions. We have obtained the values for the critical exponents γ, β and τ and compare our results with those at lower energy experiment (1.0A GeV data). The values suggest that a phase transition like behavior, is observed.
作者机构：
CCAST, World Lab, Beijing 100080, Peoples R China.;China Inst Atom Energy, Beijing 102413, Peoples R China.;Huazhong Normal Univ, Inst Particle Phys, Beijing 430079, Peoples R China.;Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90025 USA.;Acad Sinica, Inst Theoret Phys, Beijing 100080, Peoples R China.
通讯机构：
[Sa, BH] C;CCAST, World Lab, POB 8730, Beijing 100080, Peoples R China.
摘要：
The idea that the reduction of the strange quark suppression in string fragmentation leads to the enhancement of strange particle yield in nucleus-nucleus collisions is applied to study the singly and multiply strange particle production in p-Pb and Pb-Pb collisions at 158A GeV/c. In this mechanism the strange quark suppression factor is related to the effective string tension, which increases in turn with the increase of the energy, the centrality, and the mass of colliding system. The WA97 observation that the strange particle enhancement increases with the increasing centrality and the increasing strange quark content in multiply strange particles in Pb-Pb collisions with respect to p-Pb collisions was reproduced reasonably well.
摘要：
The nuclear emulsion was exposed at CERN by the lead projectile at 160 A GeV. The angles between any pair of fragments with Z = 2 - 4 have been measured in the emulsion plane for the events which did not contain heavy fragments. The constant characterizing the normal angle (cp) distribution of the fragment momentum projection onto the emulsion plane with respect to initial projectile momentum Po is found to be sigma(phi) = (0.37 +/- 0.02) mrad. Corresponding value sigma(o) = (121 +/- 6) MeV/c of nucleon momentum distribution in the lead nucleus coincides with that expected from Fermi momentum distribution for this nucleus. The peak in the pair-angle distribution of double-charged fragments, Be-8 --> 2 alpha, is presented for the region of small angles (< 0.1 mrad). The fraction of alpha-particles coming from the decay of the ground state Be-8 is found to be (13 +/- 2)% of their whole number.
会议名称：
XXVIIth International Symposium on Multiparticle Dynamics
会议时间：
SEP 08-12, 1997
会议地点：
INFN, NATL LABS, FRASCATI, ITALY
会议主办单位：
PN Lebedev Phys Inst, Moscow 117924, Russia.^High Energy Phys Inst, Almaty, Kazakhstan.^Acad Sinica, Inst High Energy Phys, Beijing, Peoples R China.^Panjab Univ, Dept Phys, Chandigarh 160014, India.^Hunan Educ Inst, Dept Phys, Changsha, Hunan, Peoples R China.^Joint Nucl Res Inst, Dubna, Russia.^Univ Rajasthan, Dept Phys, Jaipur 302004, Rajasthan, India.^Univ Jammu, Dept Phys, Jammu 180004, India.^Safarik Univ, Dept Nucl Phys & Biophys, Kosice, Slovakia.^Shanxi Normal Univ, Dept Phys, Linfen, Shanxi, Peoples R China.^Univ Lund, Dept Phys, Lund, Sweden.^Univ Marburg, Fachbereich Phys, D-3550 Marburg, Germany.^Univ Washington, Dept Phys, Seattle, WA 98195 USA.^Inst Phys Nucl, Tashkent, Uzbekistan.^Phys Tech Inst, Tashkent, Uzbekistan.^Huazhong Normal Univ, Inst Particle Phys, Wuhan, Hubei, Peoples R China.^St Petersburg Nucl Phys Inst, St Petersburg, Russia.
摘要：
Angular distributions of charged particles produced in O-16 and S-32 collisions with nuclear track emulsion were studied at momenta 4.5 and 200 A GeV/c. Comparison with the angular distributions of charged particles produced in proton-nucleus collisions at the same momentum allows to draw the conclusion, that the angular distributions in nucleus-nucleus collisions can be seen as superposition of the angular distributions in nucleon-nucleus collisions taken at the same impact parameter b(NA), that is mean impact parameter between the participating projectile nucleons and the center of the target nucleus.
摘要：
The complete charge distribution of products from Au nuclei fragmenting in nuclear emulsion at 10.7A GeV has been measured. Multiplicities of produced particles and particles associated with the target source are used to select peripheral and central events. A statistical analysis, based on event-by-event charge distributions, show that a population of subcritical, critical and supercritical events, i.e. a phase transition like behaviour, is observed among peripheral collisions.
作者机构：
[Adamovich, MI] Inst High Energy Phys, Alma Ata, Kazakhstan.;Acad Sinica, Inst High Energy Phys, Beijing, Peoples R China.;Inst Gravitat & Space Res, Bucharest, Romania.;Panjab Univ, Dept Phys, Chandigarh 160014, India.;Hunan Educ Inst, Dept Phys, Changsha, Hunan, Peoples R China.
通讯机构：
[Adamovich, MI] I;Inst High Energy Phys, Alma Ata, Kazakhstan.
摘要：
We analyse the multifractal structure of moments G(q) in terms of a new variable X on data of (197)AU, S-32, and O-16 induced interactions with emulsion nuclei and Monte Carlo generated samples. The dynamical properties of the produced particles are mapped onto multifractal spectra. We compare In(G) in experimental data of Au-197, S-32, and O-16 with pure statistical fluctuations. It is shown that the stochasticity plays an important role for the G-moments.
