Download or read book On the X IND F Distribution of J psi s Produced in Heavy Ion Collisions written by Francisco de Oliveira Durães and published by . This book was released on 2002 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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Signatures of Absorption Mechanisms for J psi And psi Production in High Energy Heavy Ion Collisions
Download or read book Signatures of Absorption Mechanisms for J psi And psi Production in High Energy Heavy Ion Collisions written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: J/psi and psi' produced in high-energy heavy-ion collisions are absorbed by their collisions with nucleons and produced soft particles, leading to two distinct absorption mechanisms. The signature of absorption by produced soft particles, as revealed by psi' production data, consists of a gap and a change of the slope in going from the pA line to the nucleus-nucleus line when we make a semi-log plot of the survival probability as a function of the path length. Using this signature, we find from the J/psi production data in pA, O-Cu, O-U, and S-U collisions that the degree of J/psi absorption by produced soft particles is small and cannot account for the J/psi data in Pb-Pb collisions. The anomalous suppression of J/psi production in Pb-Pb collisions can be explained as due to the occurrence of a new phase of strong J/psi absorption, which sets in when the local energy density exceeds about 3.4 GeV/fm3. To probe the chemical content of the new phase, we propose to study the abundance of open-charm mesons and charm hyperons which depends sensitively on the quark chemical potential.
Download or read book Signatures of Absorption Mechanisms for J And Production in High Energy Heavy Ion Collisions written by and published by . This book was released on 1997 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: J/psi and psi ̀produced in high-energy heavy-ion collisions are absorbed by their collisions with nucleons and produced soft particles, leading to two distinct absorption mechanisms. The signature of absorption by produced soft particles, as revealed by psi ̀production data, consists of a gap and a change of the slope in going from the pA line to the nucleus-nucleus line when we make a semi-log plot of the survival probability as a function of the path length. Using this signature, we find from the J/psi production data in pA, O-Cu, O-U, and S-U collisions that the degree of J/psi absorption by produced soft particles is small and cannot account for the J/psi data in Pb-Pb collisions. The anomalous suppression of J/psi production in Pb-Pb collisions can be explained as due to the occurrence of a new phase of strong J/psi absorption, which sets in when the local energy density exceeds about 3.4 GeV/fm3. To probe the chemical content of the new phase, we propose to study the abundance of open-charm mesons and charm hyperons which depends sensitively on the quark chemical potential.
Download or read book Inclusive J psi Production Measurement in Pb Pb Collisions at Sqrt s NN written by Lizardo Valencia Palomo and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum Chromodynamics predicts that the hot and dense matter produced in ultra-relativistic heavy-ion collisions, the Quark Gluon Plasma (QGP), behaves as a deconfined state of quarks and gluons. Since 1980's it was predicted that quarkonia are suppressed due to screening effects in the QGP, making quarkonia a good tool to probe the plasma.ALICE is the only experiment at the LHC that was designed and built to characterize the physics of the QGP. The muon spectrometer, one of the detectors in ALICE, is used to measure the quarkonia production at forward rapidity. In this thesis the efficiency of the tracking chambers of the muon spectrometer is studied along one year of data taking. The results obtained from real data are compared to simulations in order to compute the systematic uncertainties associated to the tracking apparatus.A complete analysis of the inclusive J/psi --> mu^+ mu^- production in the 2011 Pb-Pb collisions is also presented. The study includes the signal extraction, normalization and acceptance times efficiency corrections. An important part is dedicated to the quantify the systematic uncertainties arising from different sources. The resulting R_{AA} and p_{T} are compared to previous experiments and also to theoretical models.
Download or read book Nuclear Matter Effects on J psi Production in Asymmetric Cu Au Collisions at sqrt s mathrm NN written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on J/[psi] production from asymmetric Cu+Au heavy-ion collisions at \(\sqrt{s_{\mathrm{NN}}} = 200\) GeV at the Relativistic Heavy Ion Collider at both forward (Cu-going direction) and backward (Au-going direction) rapidities. The nuclear modification of J/[psi] yields in Cu+Au collisions in the Au-going direction is found to be comparable to that in Au+Au collisions when plotted as a function of the number of participating nucleons. In the Cu-going direction, J/[psi] production shows a stronger suppression. This difference is comparable in magnitude and has the same sign as the difference expected from shadowing effects due to stronger low-x gluon suppression in the larger Au nucleus. Thus, the relative suppression is opposite to that expected from hot nuclear matter dissociation, since a higher energy density is expected in the Au-going direction.
Download or read book Chasing the X Sub F Dependence of J Psi Production written by and published by . This book was released on 1991 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: We discuss the combined effects of hard scattering processes and intrinsic heavy-quark components in the hadron wavefunction on the x{sub f} dependence of J/[psi] production. The A dependence arises from nuclear absorption, comover interactions, shadowing of parton distributions, and intrinsic heavy quarks. 9 refs., 1 fig.
Download or read book Cold Nuclear Matter Effects on J psi e e and Psi e e Production in D Au Collisions at 200 Gev written by Darren McGlinchey and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: Mesons composed of heavy quark-antiquark pairs, known as quarkonia, provide the only direct probe of the screening length in the deconfined state of quarks and gluons, known as the quark gluon plasma (QGP), which is believed to be produced in high energy heavy ion collisions. However, the observation of suppression of quarkonia production in heavy ion collisions at high energies is complicated by the modification of quarkonia production in normal nuclear matter. Measuring the modification of quarkonia production due to the effects of normal nuclear matter, often termed cold nuclear matter (CNM) effects, provide a critical baseline for understanding the properties of the QGP. Measurements of CNM effects on quarkonia production are also interesting in their own right, and can be measured independently in proton-nucleus (p+A) collisions. The modification of quarkonia production in p+A collisions provides insight into quarkonia production mechanisms unavailable through the study of proton-proton collisions alone. The study of quarkonia production in p+A collisions over a wide range of kinematic variables can also provide constraints on the modification of parton distribution functions in nuclei. In order to quantify the CNM effects present at the Relativistic Heavy Ion Collider (RHIC), the PHENIX experiment has recorded data on d+Au collisions at \sqsn=200 GeV. The analysis of J/psi→e+e- and psi'→e+e- production from that data set is presented here. Both J/psi and psi' production are found to be suppressed in d+Au relative to p+p collisions, with the suppression increasing for collisions with small impact parameters. The psi' production is found to be much more suppressed than J/psi production, a result which is unexpected based on measurements at lower collision energy and present theoretical pictures. A parametrization of the J/psi modification measured by PHENIX in terms of two CNM effects is also presented. One is the nuclear breakup of the forming quarkonium state through collisions with nucleons during the d+Au collision. The other is the modification of the gluon distribution in the Au nucleus. It is found that the two effects can be separated due to the very different impact parameter dependencies. A strongly non-linear geometric dependence on the modification of the gluon distribution function is observed, with the modification found to be concentrated near the center of the Au nucleus. This parametrization is also used to estimate the modification of J/psi production in Au+Au collisions due to CNM effects. This modification is compared to PHENIX measurements of J/psi production in Au+Au collisions. Suppression of J/psi production in Au+Au collisions beyond CNM effects is observed. This excess suppression is interpreted as suppression of J/psi production due to the formation of a QGP.
Download or read book J psi Suppression in Heavy Ion Collisions Interplay of Hard and Soft QCD Processes written by and published by . This book was released on 1998 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hadronic Production of J Psi at Large Chi F in 800 GeV P Cu and P Be Collisions written by Matthew Scott Kowitt and published by . This book was released on 1992 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book J psi Production and Absorption in P A and D Au Collisions written by and published by . This book was released on 2010 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The level of 'anomalous' charmonium suppression in high-energy heavy-ion collisions and its interpretation as a signal of quark-gluon plasma formation requires a robust understanding of charmonium production and absorption in proton-nucleus collisions. In a previous study we have shown that, contrary to common belief, the so-called J/[psi] 'absorption cross section', [sigma]{sub abs}{sup J/[psi]}, is not a 'universal constant' but, rather, an effective parameter that depends very significantly on the charmonium rapidity and on the collision energy. Here we present ugraded Glauber calculations with the EPS09 parameterization of nuclear modifications of the parton densities. We confirm that the effective 'absorption cross section' depends on the J/{psi} kinematics and the collision energy. We also make further steps towards understanding the physics of the mechanisms behind the observed 'cold nuclear matter' effects.
Download or read book J psi and Psi 2S Production in Pp Collisions at Sqrt s written by and published by . This book was released on 2012 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: A measurement of the J/psi and psi(2S) production cross sections in pp collisions at sqrt(s)=7 TeV with the CMS experiment at the LHC is presented. The data sample corresponds to an integrated luminosity of 37 inverse picobarns. Using a fit to the invariant mass and decay length distributions, production cross sections have been measured separately for prompt and non-prompt charmonium states, as a function of the meson transverse momentum in several rapidity ranges. In addition, cross sections restricted to the acceptance of the CMS detector are given, which are not affected by the polarization of the charmonium states. The ratio of the differential production cross sections of the two states, where systematic uncertainties largely cancel, is also determined. The branching fraction of the inclusive B to psi(2S) X decay is extracted from the ratio of the non-prompt cross sections to be: BR(B to psi(2S) X) = (3.08 +/- 0.12(stat.+syst.) +/- 0.13(theor.) +/- 0.42(BR[PDG])) 10-̂3.
Download or read book J psi And psi prime Suppression in High energy Heavy ion Collisions written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The anomalous suppression of J/[psi] production in Pb-Pb collisions at 158 GeV observed by the NA50 Collaboration can be explained as due to the occurrence of a new phase of strong J/[psi] absorption, which sets in when the local energy density exceeds about 3.4 GeV/fm[sup 3]. The peculiar behavior of the[psi][sup']/[psi] ratio in[ital p]-A and nucleus-nucleus collisions can be understood as due to approximately equal[psi]-N and[psi][sup']-N absorption cross sections, but greater absorption cross sections for[psi][sup'] than J/[psi] with regard to absorption by soft particles and matter in the new phase.
Download or read book Prompt and Non prompt J psi Production in Pp Collisions at Sqrt s written by and published by . This book was released on 2011 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: The production of J/psi mesons is studied in pp collisions at sqrt(s)=7 TeV with the CMS experiment at the LHC. The measurement is based on a dimuon sample corresponding to an integrated luminosity of 314 inverse nanobarns. The J/psi differential cross section is determined, as a function of the J/psi transverse momentum, in three rapidity ranges. A fit to the decay length distribution is used to separate the prompt from the non-prompt (b hadron to J/psi) component. Integrated over J/psi transverse momentum from 6.5 to 30 GeV/c and over rapidity in the range.
Download or read book High Energy Physics Index written by and published by . This book was released on 1990 with total page 716 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book J Psi Suppression as a Signal for the Quark gluon Plasma written by and published by . This book was released on 1997 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors review the search for the quark-gluon plasma using the signal of the suppression of J/[psi] production in high-energy heavy-ion collisions. Recent anomalous J/[psi] suppression in high-energy Pb-Pb collisions observed by the NA50 Collaboration are examined and compared with earlier results from pA and nucleus-nucleus collisions with heavy ions of smaller mass numbers. The anomalous suppression of J/[psi] production in Pb-Pb collisions can be explained as due to the occurrence of a new phase of strong J/[psi] absorption, which sets in when the number of nucleon-nucleon collisions at a spatial point exceeds about 4 and corresponds to a local energy density of about 3.4 GeV/fm3.
Download or read book The Production of J psi and Associated Particles in the Collision of 530 GeV c Protons and Pions with Nuclear Targets written by and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have studied the production of the J/? and associated particles using the E672/E706 spectrometer at Fermilab. Preliminary results are presented from the first run in 1987--1988 with 530 GeV/c p/? and ?/sup −/ beams on a variety of nuclear targets. The A-dependance of J/? production with /pi//sup /minus// beam was found to agree with an A/sup ?/ parametrization with /alpha/ = 0.85 /plus minus/ 0.06 for X/sub F/ > 0.1. We have found that (41 /plus minus/ 22)% of the J//psi/'s produced in the p//pi//sup +/ beam are consistent with the radiative decay /chi/ /yields/J//psi/+?. The future analysis goals of the experiment are also discussed. 10 refs., 9 figs.
