共查询到20条相似文献,搜索用时 31 毫秒
1.
M.N. Mineva M. Hellström M. Bernas J. Gerl H. Grawe M. Pfützner P.H. Regan M. Rejmund D. Rudolph F. Becker C.R. Bingham T. Enqvist B. Fogelberg H. Gausemel H. Geissel J. Genevey M. Górska R. Grzywacz K. Hauschild Z. Janas I. Kojouharov Y. Kopatch A. Korgul W. Korten J. Kurcewicz M. Lewitowicz R. Lucas H. Mach S. Mandal P. Mayet C. Mazzocchi J.A. Pinston Zs. Podolyàk H. Schaffner Ch. Schlegel K. Schmidt K. Sümmerer H.J. Wollersheim 《The European Physical Journal A - Hadrons and Nuclei》2001,11(1):9-13
Rapidity correlations in 800 GeV proton interactions with emulsion nuclei are investigated for different targets and multiplicity
regions. To study the energy dependence, the results have been compared with proton interactions at 200 GeV and 400 GeV. A
common feature of all the interactions is the existence of strong, short-range correlations. However, no dependence of cluster
parameters on primary energy or target mass is found. A marginal increase of correlation strength with multiplicity is observed.
Received: 30 March 2001 / Accepted: 18 September 2001 相似文献
2.
F. Dengler I. Derado V. Eckardt J. Fent P. Freund H. J. Gebauer P. Malecki A. Manz K. P. Pretzl N. Schmitz P. Seyboth J. Seyerlein D. Vranić G. Wolf T. Coghen A. Eskreys K. Eskreys D. Kisielewska K. Olkiewicz B. Pawlik P. Stopa L. Suszycki 《Zeitschrift fur Physik C Particles and Fields》1986,33(2):187-196
Multiplicity distributions of charged particles produced in proton-proton, proton-argon and proton-xenon inelastic collisions at 200 GeV/c in various rapidity intervals are presented. Nuclear target data are analysed separately for the forward and the backward hemispheres. Results of a similar analysis for only negative particles are shown. The data are well parametrized in terms of negative binomial distributions. However, such a parametrization fails in describing thep-nucleus multiplicity distributions of charged particles for large rapidity intervals comprising both hemispheres. Parameters characteristic for the clan model of Giovannini and Van Hove are also presented. 相似文献
3.
J. L. Bailly S. Banerjee C. Caso Y. Chiba H. Dibon B. Epp A. Ferrando F. Fontanelli T. Gemesy A. Gurtu R. Hamatsu T. Hirose J. Hrubec Y. Iga Yu. Ivanyshenkov N. Khalatyan E. Kistenev S. Kitamura V. Kubik J. MacNaughton S. Matsumoto I. S. Mittra L. Montanet G. Neuhofer G. Pinter P. Porth T. Rodrigo J. Singh S. Squarcia K. Takahashi L. A. Tikhonova U. Trevisan T. Yamagata G. Zholobov S. A. Zotkin EHS-RCBC Collaboration 《Zeitschrift fur Physik C Particles and Fields》1988,40(2):215-221
Multiplicity distributions in various rapidity intervals for charged particles produced in collisions of 360 GeV/c protons with aluminium (Al) and gold (Au) targets are presented. The data were analysed separately for the forward and backward hemispheres. Each distribution is well described by a negative binomial distribution. The experimental distributions are compared with the predictions of the multichain model calculated by the Monte Carlo program MCMHA in which the intranuclear cascade process is included, and also with the Lund Monte Carlo FRITIOF. The results of MCMHA reproduce quite well the multiplicity distributions for various rapidity intervals. 相似文献
4.
N. Ahmad M. M. Khan A. Kamal M. D. Azmi A. R. Khan M. Zafar M. Irfan 《Indian Journal of Physics》2010,84(12):1641-1645
Results on correlation and clusterization amongst relativistic charged particles produced in 14.5A GeV/c 28Si-nucleus collisions are presented by studying rapidity density distribution of relativistic charged particles in various
pseudorapidity windows. These results are observed to agree reasonably well with the predictions of Lund Monte Carlo model
FRITIOF. 相似文献
5.
Sudhir Malik 《Zeitschrift fur Physik C Particles and Fields》1996,70(4):621-624
Experimental results on multiplicity distributions in different pseudorapidity intervals of charged shower particles produced in proton-AgBr and proton-CNO collisions at 800 GeV are presented. The different distributions are described well by the negative binomial form. We successfully interpret our results in terms of the clan model. The values of the rapidity gap probability in terms of average number of clans in different pseudorapidity intervals are also determined. 相似文献
6.
I. V. Ajinenko Yu. A. Belokopytov H. Bialkowska H. Boettcher F. Botterweck M. Charlet P. V. Chliapnikov F. Crijns A. De Roeck D. A. De Wolf K. Dziunikowska A. M. F. Endler A. Eskreys Z. C. Garutchava Y. A. Golubkov G. R. Gulkanyan P. van Hal R. Sh. Hakobyan T. Haupt W. Kittel D. Kisielewska B. B. Levchenko B. Machowski F. Meijers A. B. Micha?owska V. I. Nikolaenko K. Olkiewicz R. P?ll?nen V. M. Ronjin A. M. Rybin H. M. T. Saarikko L. Scholten L. N. Smirnova O. G. Tchikilev V. A. Uvarov F. Verbeure R. Wischnewski EHS-NA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1990,46(4):569-582
The negative binomial distribution (NBD) is fitted to all charged and to negative particle multiplicity distributions in restricted rapidity intervals, both in the forward and backward c.m. hemispheres of positive meson interactions on Al and Au nuclei. For negative particle multiplicity distributions, the NBD parameters are also determined as a function ofn g, the number of grey tracks, corresponding to varying number of intranuclear collisions. The data are interpreted in terms of the clan picture of Giovannini and Van Hove and compared to the MCMHA and Fritiof models. Both models reproduce quite well the global multiplicity distributions, but not when sub-samples are considered with fixed number of grey tracks. Regularities are better visible on the parton than on the particle level. 相似文献
7.
Sudhir Malik S. K. Soni R. K. Shivpuri 《Zeitschrift fur Physik C Particles and Fields》1995,67(2):239-244
Experimental results on multiplicity distributions for full phase space and in different pesudorapidity windows of charged secondary particles produced in proton-nucleon collisions at 800 GeV are presented and discussed. It is found that all these multiplicity distributions are well described by negative binomial distributions. We interpret our results on the basis of clan model. The bin size dependence of multiplicity distribution of charged secondary particles in proton-nucleon interactions is analysed in terms of multifractals. The values of generalised dimensions obtained from fitted distributions show a good agreement with those obtained from the data. 相似文献
8.
G. Abbiendi et al. 《The European Physical Journal C - Particles and Fields》1999,11(2):217-238
Gluon jets are identified in hadronic Z decays as all the particles in a hemisphere opposite to a hemisphere containing two tagged quark jets. Gluon jets defined
in this manner are equivalent to gluon jets produced from a color singlet point source and thus correspond to the definition
employed for most theoretical calculations. In a separate stage of the analysis, we select quark jets in a manner to correspond
to calculations, as the particles in hemispheres of flavor tagged light quark (uds) events. We present the distributions of
rapidity, scaled energy, the logarithm of the momentum, and transverse momentum with respect to the jet axes, for charged
particles in these gluon and quark jets. We also examine the charged particle multiplicity distributions of the jets in restricted
intervals of rapidity. For soft particles at large , we observe the charged particle multiplicity ratio of gluon to quark jets to be , in agreement with the prediction that this ratio should approximately equal the ratio of QCD color factors, . The intervals used to define soft particles and large for this result, GeV/ and GeV/, are motivated by the predictions of the Herwig Monte Carlo multihadronic event generator. Additionally, our gluon jet data
allow a sensitive test of the phenomenon of non-leading QCD terms known as color reconnection. We test the model of color
reconnection implemented in the Ariadne Monte Carlo multihadronic event generator and find it to be disfavored by our data.
Received: 24 February 1999 / Published online: 8 September 1999 相似文献
9.
本工作在三火球模型的基础上引进结团(cluster)机制对多种窗口的前后关联进行MonteCarlo模拟.与=200,546,900GeV的实验数据的符合表明了模型的合理性.同时从理论上说明了cluster机制对多重数关联的影响表现为短程加强,长程减弱。 相似文献
10.
对Z0能区91.2GeV正负电子湮没产生强子末态的事例,分别针对全喷注和双喷注在不同快度窗口的单、双半球空间内进行多重数分布的泊松拟合.根据/D参量及拟合度得到近泊松形式,与有关理论模型进行了比较,并讨论了与KNO无标度性的关系.分析了偏离泊松形式的有关参数与非独立粒子发射及关联强度之间的联系.利用JADE喷注分析法讨论了中心快度区的“肩状结构”. 相似文献
11.
The quark combination mechanism of hadron production is applied to nucleus-nucleus collisions at the CERN Super Proton Synchrotron (SPS) and the BNL Alternating Gradient Synchrotron (AGS). The rapidity spectra of identified hadrons and their spectrum widths are studied. The data of π-, K±, φ, Λ, Λ, Ξ- and Ξ+ at 80 and 40 A GeV, and in particular at 30 and 20 A GeV where the onset of deconfinement is suggested to happen, are consistently described by the quark combination model. However, at AGS 11.6 A GeV below the onset, the π±, K± and Λ spectra cannot be simultaneously explained, indicating the disappearance of the intrinsic correlation of their production in the constituent quark level. The collision-energy dependence of the rapidity spectrum widths of the constituent quarks, and the strangeness of the hot and dense quark matter produced in heavy ion collisions, are obtained and discussed. 相似文献
12.
V.A. Khoze A.D. Martin M.G. Ryskin 《The European Physical Journal C - Particles and Fields》2002,23(2):311-327
We study the double-diffractive production of various heavy systems (e.g. Higgs, dijet, and SUSY particles) at LHC and Tevatron collider energies. In each case we compute the probability that the rapidity gaps,
which occur on either side of the produced system, survive the effects of soft rescattering and QCD bremsstrahlung effects.
We calculate both the luminosity for different production mechanisms, and a wide variety of subprocess cross sections. The
results allow numerical predictions to be readily made for the cross sections of all these processes at the LHC and the Tevatron
collider. For example, we predict that the cross section for the exclusive double-diffractive production of a 120 GeV Higgs boson at the LHC is about 3 fb, and that the QCD background in the decay mode is about 4 times smaller than the Higgs signal if the experimental missing-mass resolution is 1 GeV. For completeness
we also discuss production via or WW fusion.
Received: 7 November 2001 / Revised version: 11 December 2001 / Published online: 25 January 2002 相似文献
13.
《Nuclear Physics A》1999,650(2):227-244
We study Pb + Pb collisions at 158 A GeV/c using hydrodynamical approach. We test different equations of state (EoSs) and different initial conditions and show that there are more than one initial state for each EoS which reproduce the observed hadronic spectra. We also find that different equations of state favor different freeze-out temperature. Simultaneously we calculate the thermal dilepton and photon spectra for each EoS and initial state. We compare the dilepton mass spectrum to data measured by the CERES collaboration and find that the differences in spectra obtained using different EoSs and initial states are not resolvable within the current experimental resolution. However, at invariant masses over 2 GeV the difference in the yield due to various initial states is close to an order of magnitude. We also study the rapidity distribution of lepton pairs and find that for masses around 800 MeV the shape of the distribution depends strongly on the EoS. 相似文献
14.
Results for the complete NLO electroweak corrections to Standard Model Higgs production via gluon fusion are included in the total cross section for hadronic collisions. Artificially large threshold effects are avoided working in the complex-mass scheme. The numerical impact at LHC (Tevatron) energies is explored for Higgs mass values up to 500 GeV (200 GeV). Assuming a complete factorization of the electroweak corrections, one finds a +5% shift with respect to the NNLO QCD cross section for a Higgs mass of 120 GeV both at the LHC and the Tevatron. Adopting two different factorization schemes for the electroweak effects, an estimate of the corresponding total theoretical uncertainty is computed. 相似文献
15.
本文用相对论动力论方程描述高能重离子碰撞时空演化,并用它分析在200A GeV的16O束流和32S束流下,于快度中心区的末态粒子快度分布,确定了不同系统的弛豫时间. 相似文献
16.
The Clustered Production of Final Particles and ForwardBackward Correlation in High Energy pp Collision 下载免费PDF全文
In this paper, forward-backward multiplicity correlation in various rapidity windows in high energy p collision is obtained by using Monte Carlo simulation based on Three Pire Ball model with cluster mechanism. The results fit the exprimental data of s=200,546,900GeV, indicating that the model is reasonable. It is shownthat the effect of cluster mechanism makes forward-backward multiplicity correlation increase in short range and decrease in long range. 相似文献
17.
18.
19.
R. Albrecht T. C. Awes C. Baktash P. Beckmann F. Berger M. A. Bloomer D. Bock R. Bock G. Claesson G. Clewing L. Dragon A. Eklund R. Ferguson A. Franz S. I. A. Garpman R. Glasow H- Å. Gustafsson H. H. Gutbrod G. Hölker J. Idh P. Jacobs K. -H. Kampert B. W. Kolb H. Löhner I. Lund F. E. Obenshain A. Oskarsson I. Otterlund T. Peitzmann F. Plasil A. M. Poskanzer M. L. Purschke H. -G. Ritter B. Roters S. Saini R. Santo H. R. Schmidt S. P. Sorensen P. Steinhaeuser K. Steffens E. Stenlund D. Stüken G. R. Young 《Zeitschrift fur Physik C Particles and Fields》1992,55(4):539-548
Multiplicity and pseudorapidity distributions have been measured for32S+Al, Cu, Ag and Au at 200A GeV. The widths of the pseudorapidity distributions increase from central to peripheral collisions. The main contribution is assumed to come from the increasing fraction of charged particles stemming from the fragmentation of the target for peripheral collisions as compared to central collisions. On the average 170–180 charged particles per unit of pseudorapidity are attained for the most central32S+Au events at the maximum of the distribution. The target dependence of the yield of charged particles for central collisions is investigated. In the target rapidity region the yield is directly proportional to the target mass. The transverse energy per charged particle has been studied as a function of centrality and pseudorapidity. The experimental results are compared to the results from the Monte-Carlo model VENUS 3.11 which includes rescattering among secondaries. A comparison between different centrality triggers is made. 相似文献
20.
J. B?chler J. Bartke H. Bia?kowska R. Bock R. Brockmann P. Buncic S. I. Chase I. Derado V. Eckardt J. Eschke et al. 《Zeitschrift fur Physik C Particles and Fields》1992,56(3):347-354
Multiplicity distributions and their second moments fornegatively charged particles produced in32S-S central and minimum bias interactions at 200A GeV are studied in various rapidity intervals. Fritiof and Venus models mostly describe the dependence of second moments on rapidity intervals in minimum bias interactions, but not in central collisions. For central collisions the behaviour of second moments might indicate enhanced multiplicity fluctuations. 相似文献