Download or read book Data driven Extraction of the Substructure of Quark and Gluon Jets in Proton proton and Heavy ion Collisions written by Yueyang Ying and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The modification of quark- and gluon-initiated jets in the quark-gluon plasma produced in heavy-ion collisions is a long-standing question that has not yet received a definitive answer from experiments. In particular, the size of the modifications differs between theoretical models. Therefore a fully data-driven technique is crucial for an unbiased extraction of the quark and gluon jet spectra and substructure. We demonstrate a fully data-driven method for separating quark and gluon contributions to jet observables using a statistical technique called topic modeling. We will also demonstrate that jet substructures, such as jet shapes and jet fragmentation function, could be extracted using this data-driven method. This proof-of-concept study is based on proton-proton and heavy-ion collision events from the PYQUEN generator with statistics accessible in Run 4 of the Large Hadron Collider. These results suggest the potential for an experimental determination of quark- and gluon-jet spectra and their substructures.
Download or read book Quarks and Gluons at Hadron Colliders written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Data from proton-antiproton collisions at high energy provide important information on constraining the quark and gluon distributions in the nucleon and place limits on quark substructure. The S asymmetry data constrains the slope of the d/u quark distributions and significantly reduces the systematic error on the extracted value of the W mass. Drell-Yan data at high invariant mass provides strong limits on quark substructure. Information on[alpha][sub s] and the gluon distributions can be extracted from high P[sub T] jet data and direct photons.
Download or read book Quark gluon Plasma Five written by and published by World Scientific. This book was released on 2016 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This is the fifth volume in the series on the subject of quark-gluon plasma, a unique phase created in heavy-ion collisions at high energy. It contains review articles by the world experts on various aspects of quark-gluon plasma taking into account the advances driven by the latest experimental data collected at both the Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC). The articles are pedagogical and comprehensive which can be helpful for both new researchers entering the field as well as the experienced physicists working on the subject."--
Download or read book Study of Quark Gluon Plasma By Particle Correlations in Heavy Ion Collisions written by Li Yi and published by Springer. This book was released on 2016-08-25 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis covers several important topics relevant to our understanding of quark-gluon plasma. It describes measurement of the third-order harmonic flow using two-particle correlations and isolation of flow and non-flow contributions to particle correlations in gold-gold collisions. The work also investigates long-range longitudinal correlations in small systems of deuteron-gold collisions. The former is related to the hydrodynamic transport properties of the quark-gluon plasma created in gold-gold collisions. The latter pertains to the question whether hydrodynamics is applicable to small systems, such as deuteron-gold collisions, and whether the quark-gluon plasma can be formed in those small-system collisions. The work presented in this thesis was conducted with the STAR experiment at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, where the center-of-mass energy of both collision systems was a factor of 100 larger than the rest mass of the colliding nuclei. The results contained in this thesis are highly relevant to our quest for deeper understanding of quantum chromodynamics. The results obtained challenge the interpretation of previous works from several other experiments on small systems, and provoke a fresh look at the physics of hydrodynamics and particle correlations pertinent to high energy nuclear collisions.
Download or read book Study of Quark Substructure Using Proton proton Collisions written by Daniel Miner and published by . This book was released on 2011 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Two or more jets are frequently produced as a result of proton-proton collisions. The angular distribution of these jets can provide a wealth of information about the underlying interactions taking place as the protons collide. In this study, we use a simple observable called the dijet centrality ratio to examine this angular distribution, and search a 35.7 pb1 sample of data at [square root]s = 7 TeV from CERN's Large Hadron Collider for evidence of quark substructure. We expect to set a 95% confidence limit on the energy scale of such interactions of [lambda]
Download or read book Jet Modification in Strongly coupled Quark gluon Plasma written by Chanwook Park and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "A deconfined plasma of quarks and gluons, known as quark-gluon plasma (QGP), is produced in relativistic heavy-ion collisions. This new state of strongly coupled matter is characterized by collective behaviour and may provide an opportunity to study Quantum Chromodynamics (QCD) under extreme temperatures and densities. One of the most remarkable experimental signatures of QGP formation is the suppression of high transverse momentum jets created in initial inelastic scattering with high momentum transfer. Measurements have demonstrated that high transverse momentum jet production in heavy-ion collisions is strongly suppressed when compared to proton-proton collisions. Interestingly, experiments of proton-lead collisions have discovered a signal of collectivity comparable to that in lead-lead collisions while no significant suppression of jet yield was observed.This thesis presents the study of jet modification in large (Pb+Pb) and small (p+Pb) colliding systems using MARTINI, a sophisticated Monte-Carlo event generator for jet evolution in heavy-ion collisions. MARTINI incorporates the AMY radiative energy loss formalism and the leading-order elastic collisional energy loss formulations. Realistic simulations at the LHC energy scales are aided by new developments in MARTINI, including the QCD running coupling, a formation time of radiation, and a thermal recoil implementation.We demonstrate that the QCD running coupling and the formation time of radiation capture the characteristics of jet quenching at the LHC energy scales. The importance of thermal recoil in describing integrated and differential jet observables is investigated. We obtain a simultaneous description of the jet nuclear modification factor and the elliptic flow coefficients for high-energy jets in p+Pb collisions using the jet quenching model within the uncertainties. This study provides a comprehensive understanding of jet quenching in heavy-ion collisions and shows an indication of quark-gluon plasma in small systems"--
Download or read book Quark gluon Plasma 4 written by Rudolph C. Hwa and published by World Scientific. This book was released on 2010 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a review volume containing articles written by experts on current theoretical topics in the subject of Quark-Gluon Plasma created in heavy-ion collisions at high energy. It is the fourth volume in the series with the same title sequenced numerically. The articles are written in a pedagogical style so that they can be helpful to a wide range of researchers from graduate students to mature physicists who have not worked previously on the subject. A reader should be able to learn from the reviews without having extensive knowledge of the background literature.
Download or read book Heavy Quarkonium Production in High Energy Proton Proton Collisions at RHIC written by and published by . This book was released on 2009 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: We update the study of the total [psi] and [Upsilon] production cross section in proton-proton collisions at RHIC energies using the QCD-based Color-Singlet (CS) Model, including next-to-leading order partonic matrix elements. We also include charm-quark initiated processes which appear at leading order in [alpha]{sub s}, but which have so far been overlooked in such studies. Contrary to earlier claims, we show that the CS yield is consistent with measurements over a broad range of J/[psi] rapidities. We also find that charm-quark initiated processes, including both intrinsic and sea-like charm components, typically contribute at least 20 % of the direct J/[psi] yield, improving the agreement with data both for the integrated cross section and its rapidity dependence. The key signature for such processes is the observation of a charm-quark jet opposite in azimuthal angle [phi] to the detected J/[psi]. Our results have impact on the proper interpretation of heavy-quarkonium production in heavy-ion collisions and its use as a probe for the quark-gluon plasma.
Download or read book Modification of K0s and Lambda AntiLambda Transverse Momentum Spectra in Pb Pb Collisions at sNN 2 76 TeV with ALICE written by Simone Schuchmann and published by Springer. This book was released on 2016-09-01 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis offers an excellent, comprehensive introduction to the physics of the quark–gluon plasma. It clearly explains the connection between theory and experiment, making the topic accessible to non-specialists in this field. The experimental work, which contributes significantly to our understanding of the quark–gluon plasma, is described in great detail. The results described in the final chapters of the thesis provide interesting new ideas about the connection between proton-proton and Pb-Pb collisions. Simone Schuchmann received the 'ALICE Thesis Award 2016' for this excellent work.
Download or read book Quark Gluon Plasma 3 written by Rudolph C. Hwa and published by World Scientific. This book was released on 2004 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation. Text reviews the major topics in Quark-Gluon Plasma, including: the QCD phase diagram, the transition temperature, equation of state, heavy quark free energies, and thermal modifications of hadron properties. Includes index, references, and appendix. For researchers and practitioners.
Download or read book Jetting Through the Primordial Universe written by Raghav Kunnawalkam Elayavalli and published by . This book was released on 2017 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Collisions of heavy ion nuclei at relativistic speeds (close to the speed of light), sometimes referred to as the ``little bang", can recreate conditions similar to the early universe. This high temperature and very dense form of matter, now known to consist of de-confined quarks and gluons is named the quark gluon plasma (QGP). An early signature of the QGP, both theorized and seen in experiments, was the aspect of ``jet quenching" and understanding that phenomenon will be the main focus of this thesis. The concept behind quenching is that a high energetic quark or gluon jet undergoes significant energy loss due to the overall structure modifications related to its fragmentation and radiation patterns as it traverses the medium. The term jet, parameterized by a fixed lateral size or the jet radius, represents the collimated spray of particles arising from an initial parton. In this thesis, Run1 experimental data from pp and heavy ion collisions at the CERN LHC is analyzed with the CMS detector. Analysis steps involved in the measurement of the inclusive jet cross section in pp, pPb and PbPb systems are outlined in detail. The pp jet cross section is compared with next to leading order theoretical calculations supplemented with non perturbative corrections for three different jet radii highlighting better comparisons for larger radii jets. Measurement of the jet yield followed by the nuclear modification factors in proton-lead at 5.02 TeV and lead-lead collisions at 2.76 TeV are presented. Since pp data at 5.02 TeV was not available in Run1, an extrapolation method is performed to derive a reference pp spectra. A new data driven technique is introduced to estimate and correct for the fake jet contribution in PbPb for low transverse momenta jets. The nuclear modification factors studied in this thesis show jet quenching to be attributed to final state effects, have a strong correlation to the event centrality, a weak inverse correlation to the jet transverse momenta and an apparent independence on the jet radii in the kinematic range studied. These measurements are compared with leading theoretical model calculations and other experimental results at the LHC leading to unanimous agreement on the qualitative nature of jet quenching. This thesis also features novel updates to the Monte Carlo heavy ion event generator JEWEL (Jet Evolution With Energy Loss) including the boson-jet production channels and also background subtraction techniques to reduce the effect of the thermal background. Keeping track of these jet-medium recoils in JEWEL due to the background subtraction techniques significantly improves its descriptions of several jet structure and sub-structure measurements at the LHC.
Download or read book Subjet Multiplicity of Quark and Gluon Jets Reconstructed with the K Algorithm in P p Collisions written by Robert Michael Snihur and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents some of the first experimental results of the k⊥ jet algorithm at a hadron collider. Gluon jets dominate the final state of proton-antiproton (pp¯) collisions at high center-of-mass energies ( s = 1800 GeV). Quark jets make up a significant fraction of the jet cross section only at high jet transverse momentum pT or low s . For fixed pT, we compare jets at s = 1800 GeV to s = 630 GeV, and interpret differences in terms of differing contributions from gluon and quark jets. We define jets with a successive combination algorithm based on relative transverse momenta ( k⊥ ). To study jet structure, the k⊥ algorithm is then applied within the jet to resolve subjets. We measure the number of subjets within mixed quark and gluon jet samples at s = 1800 and 630 GeV. A simple method is used to extract measurements of pure quark and gluon jet samples separately. The method requires knowledge of the relative mix of quarks and gluons in the two s samples, which we derive from Monte Carlo and a detailed detector simulation. The number of subjets emitted in gluon jets is measured to be approximately twice that in quark jets.
Download or read book Measuring the Quark and Gluon Jet Energy Response in Proton proton Collisions at 7 TeV Center of mass Energy with the ATLAS Detector written by David Johnny Shinkaruk and published by . This book was released on 2013 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: The jet energy scale is one of the largest systematic uncertainties in physics analyses at ATLAS, making it vital to understand and minimize. This thesis provides a comprehensive study of the quark and gluon jet responses, by comparing results of the missing transverse energy projection fraction method in the established gamma+jet events and the newly developed analysis of dijet events. A likelihood discriminator is used to tag jets according to their calorimeter response, and correct the response to one for the dijet study. The mean energy of quark and gluon tagged jets is shown to differ by 4-7%, depending on the energy of the jet.
Download or read book Fragmentation of Quark and Gluon Jets in Proton antiproton Collisions at Center of mass Energy of 1 8 TeV written by Alexandre P. Pronko and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: We report the first model independent measurement of charged particle multiplicities in quark and gluon jets, Nq_ and Ng_, produced at the Tevatron in proton-antiproton collisions with center-of-mass energy 1.8 TeV and recorded by the Collider Detector at Fermilab. The measurements are made for jets with average energies 41 and 53 GeV by counting charged particle tracks in cones with opening angle of thetac_=0.28, 0.36, and 0.47 rad around the jet axis. The corresponding jet hardness Q=Ej_et*thetac_ varies in the range from 12 GeV to 25 GeV. At Q=19.2 GeV, the ratio of multiplicities r=Ng_/Nq_ is found to be 1.64"0.17, where statistical and systematic uncertainties are added in quadrature. The results are in agreement with re-summed perturbative QCD calculations and are consistent with recent ee− measurements.
Download or read book Quark and Gluon Production in Ultrarelativistic Heavy Ion Collisions written by Kari J. Eskola and published by . This book was released on 1991 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Probing Quark Gluon Plasma and Chiral Effects in Heavy Ion Collisions Measurements of Strangeness Omega and phi Production and Identified Particle Correlation in Au Au Collisions at STAR RHIC written by Liwen Wen and published by . This book was released on 2019 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultra-relativistic heavy-ion collision produces an extremely hot and dense medium of de-confined quarks and gluons, which is called Quark-Gluon Plasma (QGP). The STAR detector at Relativistic Heavy Ion Collider (RHIC) provides powerful experimental capabilities to probe the properties of this new form of matter, as well as novel quantum effects induced by the restoration of fundamental symmetry in qauntum-chromdynamics (QCD). Towards these goals, two research projects have been carried out at STAR/RHIC and will be presented in this thesis: 1) Measurement of mid-rapidity ($|y|0.5$) multi-strangenss particle ($\Omega$ and $\phi$) production in Au+Au collisions at $\sqrt{s_{NN}}=14.5$ GeV; 2) A systematic search for chiral effects using identified particle correlation. Production mechanism for strange hadrons could be dramatically different in the presence of QGP compared to regular $pp$ collisions. Thus strangeness signal is used extensively in Beam Energy Scan I (BES-I) program at RHIC to map out the phase diagram of QCD matter. As a part of BES-I, gold nuclei are collided at $\sqrt{s_{NN}} = 14.5$ GeV and the productions of mid-rapidity $\Omega(sss)$ and $\phi(\bar{s}s)$ are measured for the collisions. The ratio of anti-omega ($\bar{\Omega}$) over omega ($\Omega^-$) is calculated and used to extract thermodynamics parameters ($\mu_B/T$ and $\mu_S/T$) of collision system via statistical model. Additionally, the transverse momentum ($p_T$) dependence of nuclear modification factor ($R_{cp}$) is measured for $\phi$ meson and the result shows similar feature to energies lower than 19.6 GeV. As a test of coalescence formation mechanism for strange hadrons, $\textrm{N}(\Omega^-+\bar{\Omega}^+)/2(\textrm{N}(\phi))$ as a function of $p_T$ is studied and the data from central collision is found to deviate from model calculation and higher energy ($\sqrt{s_{NN}}19.6$ GeV) results in $p_T$ range from $2.0-3.0$ GeV/c, which may imply a transition of created medium whose underlying dominant degrees of freedom change from quarks/gluons to hadrons as collision energy goes below 19.6 GeV. %whose underlying dominant degrees of freedom change from quarks/gluons to hadrons as... With excellent particle identification capability of STAR, a systematic search for the Chiral Magnetic Effect (CME) via measurements of $\gamma_{112}$ correlation and $\kappa_K$ parameter for identified particle pairs ($\pi\pi$, $pK$, $\pi K$, $pp$, $p\pi$) in Au+Au collisions has been conducted. The $\kappa_K$ results are compared to expectations from the \textit{A Multi-Phase Transport Model} (AMPT) simulations. Except $\pi\pi$ and $pp$ correlations, the CME signals from other particle pairs are consistent with background model. $\kappa_K$ from $\pi\pi$ shows higher values than background expectation, while the result for $pp$ is even lower than the background, which requires further investigation. %A study of $\gamma_{112}$ and $\delta$ correlations for $\Lambda p$ in Au+Au 27 GeV shows that in mid-central and mid-peripheral collisions, baryon numbers are separated across reaction plane, which is consistent with the Chiral Vortical Effect (CVE) expectation. To search for Chiral Vortical Effect (CVE), a measurement of $\gamma_{112}$ and $\delta$ correlations for $\Lambda p$ pairs in Au+Au collisions at $\sqrt{s_{NN}}=27$ GeV was carried out and the results show that the CVE induced baryon number separation may exist in mid-central and mid-peripheral collisions with little contamination from flowing resonance decay background. Future development of searches for the chirality effect in heavy ion collisions will also be discussed.
Download or read book Quark Gluon Plasma and Cold Nuclear Matter Modification of Y States at square Root superscript S NN written by Santona Tuli and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum chromodynamics describes the phases of strongly-interacting matter and their boundaries, including the deconfined quark-gluon plasma (QGP) phase reached in the high energy density regime. Properties of the QGP are studied using ultrarelativistic collisions of fully-ionized heavy nuclei, which also exhibit (cold) nuclear matter properties unrelated to the plasma. An indicator of the QGP temperature is the modification of quarkonium production in collisions between two heavy ions relative to collisions between two protons. The modification in collisions between a heavy ion and a proton, where the QGP is typically not produced but nuclear matter is abundant, provides an essential baseline. Production cross sections of Y(1S), Y(2S), and Y(3S) mesons decaying into [mu]+[mu]− in proton-lead (pPb) collisions are measured using data collected by the CMS experiment at [square root][superscript s]NN = 5.02 TeV. Nuclear modification factors R[subscript pPb] for all three Y states, obtained using measured proton-proton (pp) cross sections at the same collision energy, show that Y states are suppressed in pPb collisions compared to pp collisions. Sequential ordering of the Y R[subscript pPb], with Y(1S) least suppressed and Y(3S) most suppressed, indicates presence of final- state modification of Y mesons in pPb collisions. The R[subscript pPb] of individual Y states are found to be consistent with constant values when studied as functions of transverse momentum and center-of-mass rapidity. Predictions using the final-state comover interaction model, which incorporates sequential suppression of bottomonia in pPb, are found to be in better agreement with the measured R[subscript pPb] versus rapidity than predictions using initial-state mod- ification models. Nuclear modification is less pronounced in pPb collisions than in lead-lead collisions, where the additional lead nucleus and QGP effects result in greater Y suppression. Forward-backward production ratios R[subscript FB] of Y states, which help investigate regions of different nuclear matter densities, are found to be consistent with unity and constant with increasing event activity measured both far away from and near to the measured Y.
