Download or read book Measurement of Long range Near side Two particle Angular Correlations in Pp Collisions at sqrt s written by and published by . This book was released on 2015 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our results on two-particle angular correlations for charged particles produced in pp collisions at a center-of-mass energy of 13 TeV are presented. The data were taken with the CMS detector at the LHC and correspond to an integrated luminosity of about 270 nb-1. The correlations are studied over a broad range of pseudorapidity).
Download or read book Long range Angular Correlations on the Near and Away Side in P Pb Collisions at sNN written by Betty Abelev and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Angular correlations between charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV for transverse momentum ranges within 0.5
Download or read book Insight Into Particle Production Mechanisms Via Angular Correlations of Identified Particles in Pp Collisions at s written by Jaroslav Adam and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two-particle angular correlations were measured in pp collisions at s√=7 TeV for pions, kaons, protons, and lambdas, for all particle/anti-particle combinations in the pair. Data for mesons exhibit an expected peak dominated by effects associated with mini-jets and are well reproduced by general purpose Monte Carlo generators. However, for baryon-baryon and anti-baryon-anti-baryon pairs, where both particles have the same baryon number, a near-side anti-correlation structure is observed instead of a peak. This effect is interpreted in the context of baryon production mechanisms in the fragmentation process. It currently presents a challenge to Monte Carlo models and its origin remains an open question.
Download or read book Pseudorapidity Dependence of Long range Two particle Correlations in p Pb Collisions at sqrt s NN written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Two-particle correlations in pPb collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV are studied as a function of the pseudorapidity separation (Delta eta) of the particle pair at small relative azimuthal angle (abs(Delta phi)
Download or read book A Study of Jets at the STAR Experiment at the Relativistic Heavy Ion Collider Via Two particle Correlations written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Jets have been studied in high energy heavy ion collisions by measuring the angular correlation between particles at high transverse momentum. Differences in the yield and shape of the angular correlations as a function of system size give information on the medium produced in the collision. Such modifications can be used to infer the presence of a Quark-Gluon Plasma phase, wherein parton degrees of freedom are manifest over nuclear rather than nucleonic scales. In the present work, two-particle correlations were studied in \(d+Au\) and \(Au+Au\) collisions at \(\sqrt{s_{NN}}\) = 200 GeV measured by the STAR experiment at RHIC. The technique was extended to include pseudo-rapidity, permitting jets to be characterised in two-dimensions, and enabling the jet shape to be studied in greater detail. Corrections were developed for the incomplete detector acceptance and finite two-track resolution. Both unidentified and identified particle correlations were studied, using charged tracks and neutral strange particles \(\Lambda, \overline{\Lambda}\), and \(K^0_{Short}\) reconstructed from their characteristic \(V\)0 decay topology. The focus of the analysis was the correlation peak centred at zero azimuthal separation, which is significantly enhanced in central \(Au+Au\) collisions compared to lighter systems. The modified peak was found to comprise a jet-like peak broadened in the pseudo-rapidity direction, sitting atop a long range pseudo-rapidity correlation. The former is suggestive of jet modification by the medium, and the latter may indicate a medium response to jets. Correlations with identified particles indicated the modified same side peak may in part be formed from particles originating from the underlying event.
Download or read book Long range and Short range Dihadron Angular Correlations in Central PbPb Collisions at a Nucleon nucleon Center of Mass Energy of 2 76 TeV written by and published by . This book was released on 2011 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: First measurements of dihadron correlations for charged particles are presented for central PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV over a broad range in relative pseudorapidity, Delta(eta), and the full range of relative azimuthal angle, Delta(phi). The data were collected with the CMS detector, at the LHC. A broadening of the away-side (Delta(phi) approximately pi) azimuthal correlation is observed at all Delta(eta), as compared to the measurements in pp collisions. Furthermore, long-range dihadron correlations in Delta(eta) are observed for particles with similar phi values. This phenomenon, also known as the "ridge", persists up to at least.
Download or read book Measurement of the Cross Section and Angular Correlations for Associated Production of a Z Boson with B Hadrons in Pp Collisions at sqrt s written by and published by . This book was released on 2013 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Charged Particle Transverse Momentum Spectra 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 charged particle transverse momentum (pT) spectra are presented for pp collisions at sqrt(s)=0.9 and 7 TeV. The data samples were collected with the CMS detector at the LHC and correspond to integrated luminosities of 231 inverse microbarns and 2.96 inverse picobarns, respectively. Calorimeter-based high-transverse-energy triggers are employed to enhance the statistical reach of the high-pT measurements. The results are compared with both leading-order QCD and with an empirical scaling of measurements at different collision energies using the scaling variable xT = 2 pT/sqrt(s) over the pT range up to 200 GeV/c. Using a combination of xT scaling and direct interpolation at fixed pT, a reference transverse momentum spectrum at sqrt(s)=2.76 TeV is constructed, which can be used for studying high-pT particle suppression in the dense QCD medium produced in heavy-ion collisions at that centre-of-mass energy.
Download or read book Measurement of the Prompt Double J psi Production Cross Section in Pp Collisions at Sqrt s written by Andrew David York and published by . This book was released on 2013 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: The simultaneous production of two J/psi mesons has been significantly observed in proton-proton collisions at a center-of-mass energy of 7 TeV with the CMS detector. The two J/psi mesons are fully reconstructed in their decay to muons. The signal yield is extracted with an extended maximum likelihood fit based on four event variables. A method was developed to correct for detector acceptances and efficiencies based on the measured momenta of the J/psi and their decay muons to maintain the least model dependence possible. The measurement is performed in an acceptance region defined by the individual J/psi transverse momentum and rapidity. From the measured signal yield of 446 events corresponding to an integrated luminosity of 4:7 inverse femtobarn. The total cross section is found to be 1:49 nanobarn, with 0:07 statistical and 0:13 nb systematic error, and unpolarizaed production was assumed. Most predictions for particle production at the LHC assume dominance of single parton interaction for proton-proton collisions, which can be tested with the final state measured in this analysis. The differential cross section is measured in bins of the double J/psi invariant mass, the double J/psi transverse momentum, and the absolute difference in rapidity of the two J/psi. The reconstruction of the four charged muon trajectories heavily relies on the Pixel subdetector located close to the beampipe. Systematic studies with cosmic muons and tracks from collision events are presented. The development of the Pixel RawToDigi package, data quality monitoring packages, commissioning studies of Pixel data and tracks in first collisions, and realistic simulations of decay signals in the pixel subdetector were all performed as a part of this dissertation work.
Download or read book Measurements of Di jet 0 h Correlations in Light heavy Ion Collisions at RHIC PHENIX written by Abinash Pun and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The possible presence of Quark-Gluon Plasma (QGP), the new state of matter created at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) in Au+Au and Pb+Pb collisions, is currently under investigation for smaller collisions systems such as light-heavy ions and even p+p. Long range angular correlations of particles produced in p+Pb, p+Au, d+Au, and 3He+Au, show evidence of QGP collective flow, but another signature, QGP-induced jet energy loss effects has not been identified. To address this situation, in this dissertation, a recently introduced observable RI is employed in light-heavy ion collisions. RI is derived from two-particle correlation method commonly used to study jet modification from energy loss in Au+Au.
Download or read book Two particle Correlations in Angular and Momentum Space in Heavy Ion Collisions at STAR written by Elizabeth Wingfield Oldag and published by . This book was released on 2013 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: For over a decade studies of the strong interaction in extremely dense nuclear environments have been done at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It is hypothesized that colliding two beams of Au nuclei at relativistic speeds creates an environment of hot dense nuclear matter where the quarks and gluons inside the nucleus, which are normally confined within the protons and neutrons, become deconfined into a soup called the quark-gluon plasma. Since direct observation of this short-lived phase is impossible, many sophisticated analysis techniques attempt to study the early interactions via the final state particles. What has emerged from analyses of the data are two, contradictory paradigms for understanding the results. On the one hand the colliding quarks and gluons are thought to strongly interact and reach thermal equilibrium. The other view is that primary parton-parton scattering leads directly to jet fragmentation with little effect from re-scattering. It is in principle possible to distinguish and perhaps falsify one or both of these models of relativistic heavy ion collisions via the analysis of two-particle correlations among all charged particles produced in [mathematical symbols] = 200 GeV Au+Au collisions at the STAR experiment at RHIC. This dissertation presents studies of two-particle correlations, whose derivation can be traced back to Pearson's correlation coefficient, in transverse momentum and angular space. In momentum space a broad peak is observed extending from 0.5-4.0 GeV/c which, as a function of nuclear overlap, remains at a fixed position while monotonically increasing in amplitude. Comparisons to theoretical models suggests this peak is from jet fragmentation. In a complementary study the momentum distribution of correlations in ([eta],[phi]) space is investigated. The momentum distribution of correlated pairs that contribute to the peak near the origin, commonly associated with jet fragmentation, is peaked around 1.5 GeV/c and does not soften with increased centrality. These measurements present important aspects of the available six dimensional correlation space and provide definitive tests for theoretical models. Preliminary findings do not appear to support the hypothesis of a strongly interacting QGP where back-to-back jets are expected to be significantly suppressed.
Download or read book Long range Pseudorapidity Correlations at High Pt in square Root nn written by Martin John Michael Codrington and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Quark Gluon Plasma (QGP) is a form of matter in which quarks and gluons are deconfined, and was suggested to be formed in high-energy heavy-ion collisions. Since the discovery of high-pT hadron suppression in central Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC), and the related discovery of the quenching of the away-side jet in these collisions, the role of jets as key probes of the QGP was re-affirmed. The Solenoidal Tracker At RHIC (STAR) detector system, which is suited for jet studies because of its large solid-angle coverage, has produced a number of interesting jet measurements in recent years, including gamma-jet measurements, attempts at full heavy-ion jet reconstruction, and two-dimensional correlations. A long-range correlation in pseudorapidity (the "Ridge") was studied (with statistical significance) out to pT^trig.
Download or read book Particle Ratios at High Transverse Momentum in Pp Collisions At Sqrt S written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The production of identified charged particles in pp collisions at .sqrt.s = 63 GeV with an identified high p/sub T/ trigger particle emitted in the central region is studied. The measurements were performed at the CERN ISR using the Axial Field Spectrometer. Trigger particle ratios, sigma(.pi./sup + -/)/ sigma(all/sup + -/), sigma(K/sup + -/) and sigma(p/sup + -/)/sigma(all/sup + -/) are presented for p/sub T/ from 5 GeV/c to 8 GeV/c. In addition sigma(.pi./sup + -/)/sigma(all/sup + -/) is presented in the p/sub T/ region from 2.5 GeV/c to 4.5 GeV/c. The charge compensation in the hemisphere containing the trigger particle is shown to depend strongly on the identity of the trigger particle and on the identity of the associated particles. 13 references.
Download or read book Measurement of Two particle Correlations in 800 MeV PA Collisions written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Two-particle (p-p, p-d) coincidence has been measured in p + A collisions. Production mechanism of backscattered proton has been studied by forward-backward coincidence events. Data show the importance of 2N-cluster scattering and/or multiple scattering processes involving a few nucleons. They also show that the nucleon-nucleon quasi-elastic-scattering is not the dominant part of the backscattered proton production.
Download or read book PHENIX Results on Centrality Dependence of Yields and Correlations in D Plus Au Collisions at Root S NN written by and published by . This book was released on 2016 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: PHENIX has measured the transverse momentum (pT) spectra and two particle angular correlations for high pT particles in d+Au collisions at psNN=200 GeV using the RHIC Year-2008 run data. The azimuthal angle correlations for two particles with a large rapidity gap exhibit a ridge-like structure. Using the pi-0s reconstructed in the EMCal, we have successfully extended the pT reach of the correlation up to 8 GeV/c. We find that the azimuthal anisotropy of hadrons found at low pT persists up to 6 GeV/c with a significant centrality and pT dependence, similar to what was observed in A+A collisions.
Download or read book Measurement of Prompt Psi 2S to J psi Yield Ratios in PbPb and Pp Collisions at Sqrt s NN written by and published by . This book was released on 2014 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ratio between the prompt psi(2S) and J/psi yields, reconstructed via their decays into muon pairs, is measured in PbPb and pp collisions at sqrt(s[NN]) = 2.76 TeV. The analysis is based on PbPb and pp data samples collected by CMS at the LHC, corresponding to integrated luminosities of 150 inverse microbarns and 5.4 inverse picobarns, respectively. The double ratio of measured yields, (N[psi(2S)]/N[J/psi])[PbPb] / (N[psi(2S)]/ N[J/psi])[pp], is computed in three PbPb collision centrality bins and two kinematic ranges: one at midrapidity, abs(y)
Download or read book Relativistic Fluid Dynamics In and Out of Equilibrium written by Paul Romatschke and published by Cambridge University Press. This book was released on 2019-05-09 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past decade has seen unprecedented developments in the understanding of relativistic fluid dynamics in and out of equilibrium, with connections to astrophysics, cosmology, string theory, quantum information, nuclear physics and condensed matter physics. Romatschke and Romatschke offer a powerful new framework for fluid dynamics, exploring its connections to kinetic theory, gauge/gravity duality and thermal quantum field theory. Numerical algorithms to solve the equations of motion of relativistic dissipative fluid dynamics as well as applications to various systems are discussed. In particular, the book contains a comprehensive review of the theory background necessary to apply fluid dynamics to simulate relativistic nuclear collisions, including comparisons of fluid simulation results to experimental data for relativistic lead-lead, proton-lead and proton-proton collisions at the Large Hadron Collider (LHC). The book is an excellent resource for students and researchers working in nuclear physics, astrophysics, cosmology, quantum many-body systems and string theory.
