Download or read book In jet Tracking Efficiency Analysis for the Star Time Projection Chamber in Polarized Proton proton Collisions square Root Of written by Liaoyuan Huo and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As one of the major mid-rapidity tracking devices of the STAR detector at the Relativistic Heavy-Ion Collider (RHIC), the Time Projection Chamber (TPC) plays an important role in measuring trajectory and energy of high energy charged particles in polarized proton-proton collision experiments. TPC's in-jet tracking efficiency represents the largest systematic uncertainty on jet energy scale at high transverse momentum, whose measurement contributes to the understanding of the spin structure of protons. The objective of this analysis is to get a better estimation of this systematic uncertainty, through methods of pure Monte-Carlo simulation and real- data embedding, in which simulated tracks are embedded into real-data events. Be- sides, simulated tracks are also embedded into Monte-Carlo events, to make a strict comparison for the uncertainty estimation. The result indicates that the unexplained part of the systematic uncertainty is reduced to 3.3%, from a previous quoted value of 5%. This analysis also suggests that future analysis, such as embedding jets into zero-bias real data and analysis with much higher event statistics, will benefit the understanding of the systematic uncertainty of the in-jet TPC tracking efficiency.

Download or read book Inclusive Jet and Dijet Production in Polarized Proton proton Collisions at the Square Root of Sigma written by Tai Sakuma and published by . This book was released on 2010 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: The inclusive jet cross section, the dijet cross section, and the dijet longitudinal double spin asymmetry ALL in polarized proton-proton collisions at [square root of sigma] = 200 GeV are measured with a data sample of 5.4 pbm collected with the STAR detector during RHIC Run-6. The inclusive cross section is measured as a function of jet transverse momentum PT in the range of 10

Download or read book Dijet Production in Polarized Proton proton Collisions at the Square Root of Sigma written by Matthew Hsing Hung Walker and published by . This book was released on 2011 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polarized deep inelastic scattering (DIS) experiments indicate that quarks only carry approximately 30% of the proton spin, which led to interest in measuring the contributions of other components. Through polarized proton-proton collisions at the Relativistic Heavy Ion Collider (RHIC), the world's only polarized proton collider, it is possible to make an extraction of the polarized gluon distribution function [delta]g(x). This function describes the contribution of the gluon polarization to the proton spin. This thesis presents a measurement of the p + p ---> Jet + Jet + X (dijet) cross section from the 2005 RHIC running period and a measurement of the longitudinal double spin asymmetry ALL from the 2009 RHIC running period, both made using the Solenoidal Tracker at RHIC (STAR). The cross section is measured over the invariant mass range 20

Download or read book Longitudinal Double Spin Asymmetry for Inclusive Jet Production in Polarized Proton proton Collisions at square Root Of S written by Julie Marie Millane and published by . This book was released on 2008 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the Inclusive Jet Longitudinal Double-Spin Asymmetry for polarized protons at \s = 200 GeV. The data were taken on the STAR experiment at RHIC during the 2005 run period and cover a jet transverse momentum range of 5

Download or read book Jet Characterization in Au Au Collisions at STAR written by Alán Dávila Leyva and published by . This book was released on 2013 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present study combines modern jet reconstruction algorithms and particle identification (PID) techniques in order to study the enhancement of proton/pion ratio at mid transverse momentum ([mathematical symbols] 1.5 - 4.0 GeV/c) observed in central Au + Au collisions at [mathematical symbols] = 200 GeV. The ratio enhancement is thought to be caused by recombination processes and/or parton fragmentation modification of jets in relativistic heavy ion collisions. The fragmentation modification hypothesis is tested in this analysis by reconstructing and selecting energetic jets presumably biased to fragment outside of the medium created in Au + Au collisions and comparing their particle composition to the recoiling (medium-traversing) jets. The bias assumption is confirmed by comparing jets in central collisions, where the effect of proton/pion enhancement is present, with peripheral ones where no medium effects are expected. The selected jets are reconstructed by using the anti-k[subscript T] algorithm from the modern FASTJET package. The PID in the p[subscript T] region of interest is possible by combining measurements of the particles' energy deposition and velocity from the Time Projection Chamber and the recently installed (2009-2010) Time of Flight detectors at STAR. The acceptance of these detectors, [eta]

Download or read book Study of Inclusive Jet Production and Jet Shapes in Proton proton Collisions at square Root Of S written by Francesc Vives Vaqué and published by . This book was released on 2011 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Jet Production in Ultra relativistic Polarized Proton proton Collisions written by Dylan Thein and published by . This book was released on 2005 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurement of Double Longitudinal Spin Asymmetry of Jet pi Correlations in Polarized Proton proton Collisions at square Root Of S written by James Prewitt Hays-Wehle and published by . This book was released on 2013 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: Inclusive measurements from polarized proton-proton collisions at RHIC have constrained [Delta]g, the polarized gluon distribution function of the proton. Correlation observables, such as this pion+jet measurement, allow for reconstruction of initial parton kinematics and are thus sensitive to the x dependence of [Delta]g. By measuring charged pions opposite a jet, this particular measurement can be sensitive to the flavor of the struck parton. This measurement, which is dominated by the quark-gluon subprocess, can be divided into terms proportional to [Delta]u[Delta]g and [Delta]d[Delta]g. The relatively larger quark polarization amplifies the measured asymmetry thereby enhancing the statistical power. This thesis presents the result of the mid-rapidity pion+jet longitudinal double spin asymmetry analysis from 10.6 pb-1 of luminosity collected in the 2009 200 GeV p+p run.

Download or read book Jet Energy Scale and Resolution Measured in Proton proton Collisions at square Root s written by ATLAS Collaboration CERN and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Longitudinal Double spin Asymmetry and Cross Section for Inclusive Neutral Pion Production in Polarized Proton Collisions at the Square Root of Sigma written by Alan Michael Hoffman and published by . This book was released on 2009 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Twenty years of polarized lepton-nucleon scattering experiments have found that the contribution from quark spins (1/2[delta] [sigma]) to the spin of the proton is only ~ 35%. This has lead researchers to look elsewhere, specifically to gluon spin ([delta sigma]) for a large contribution to proton spin. [delta sigma] has been only loosely constrained in polarized DIS and SIDIS experiments. Polarized proton-proton collisions at RHIC provide sensitivity to [delta sigma] through measurements of the longitudinal double-spin asymmetry, ALL. This work presents a measurement of ALL for inclusive 7ro production in polarized proton-proton collisions using the STAR detector and data from RHIC Run 6. 7r0s are abundantly produced at mid-rapidity in proton-proton collisions, making them natural candidates for studies of [delta] [sigma]. Novel techniques for reconstructing 7ros at STAR are discussed, and a measurement of the unpolarized cross section presented. Finally, the measured ALL is compared to perturbative QCD predictions and from this comparison constraints are placed on [delta] [sigma].

Download or read book Measurement of Four jet Production in Proton proton Collisions at sqrt s written by and published by . This book was released on 2013 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurement of the Longitudinal Double Spin Asymmetry for Dijet Production in Polarized Proton Proton Collisions at Sqrt s written by Daniel L. Olvitt and published by . This book was released on 2017 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding what contributes to the intrinsic angular momentum (spin) of the proton has been a major goal of the nuclear physics community. In the 1980s, it was discovered that quarks contribute 30% to the spin of the proton. This information led to a search to find other contributions to the spin of the proton. At STAR, the double spin asymmetry (ALL) is measured as it is sensitive to the polarized gluon distribution (Dg(x)). The STAR 2009 inclusive jet ALL at sqrt(s) = 200 GeV has been incorporated into two independent global fits. These fits show for the first time a statistically significant non-zero gluon contribution to the spin of the proton in the parton momentum fraction range x > 0.05. Dijet ALL is also measured at STAR. Dijets are advantageous since the parton momentum fraction (x) of the initial partons may be reconstructed to first order from final state measurements. In 2013 STAR collected an estimated 250 pb-1 of data at sqrt(s) = 510 GeV. The higher center of mass energy will allow STAR to probe Dg(x) at x values as low as 0.02. The large statistics will allow a reduction in the uncertainties. Once the data is incorporated into future global fits, it will allow for a more precise determination of Dg(x). The 2013 dijet ALL results will be presented. The results show good agreement with both global fits and previous STAR results dijet measurements.

Download or read book A Measurement of the Underlying Event Distributions in Proton Proton Collisions at Sqrt s written by Joseph Salvatore Virzi and published by . This book was released on 2012 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Underlying Event distributions are studied in events containing at least one charged particle jet produced in proton-proton collisions at sqrt(s) = 7 TeV. Jets are reconstructed from charged particles using the anti-Kt algorithm with radius parameter R = 0.6. The jet with the largest transverse momentum (pT) and.

Download or read book A Study of Medium Induced Jet Modificaiton at the Relativistic Heavy Ion Collider Via Two Particle Correlations and Identified Jet Spectra written by Essam Othman Elhalhuli and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This work has studied the particle composition of jets by determining the ratios p±/p± and K±/p± in Au + Au and d + Au collisions at vsNN = 200 GeV measured by the STAR experiment at RHIC. Jets were found by measuring the angular azimuthal correlation between particles at high transverse momentum. Jets were then identified by their back-to-back correlation. A technique was developed to identify charged particles using their specific ionisation measured in the STAR Time Projection Chamber (TPC). This thesis contains one of the first implementations of using direct photons to tag jets in heavy ion collisions. An attempt was made to extract a trigger sample rich in direct photons from neutral triggers. The hadron ratios were calculated from the jet yields as a function of transverse momentum in each collision system. Although the away side yield is suppressed in central Au + Au, there is no evidence that the relative particle yields are changed. The hadron ratios for the three systems were found to be consistent with simulated p + p events generated using the Pythia Monte Carlo event generator. This reinforces the conclusion that the fragmentation process is unchanged by interactions with the medium.

Download or read book Measuring the Spin Structure of the Proton with the STAR Detector at RHIC written by and published by . This book was released on 1996 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: A unique aspect of RHIC is the ability to collide beams of polarized protons at (square root)s = 200 and 500 GeV. The STAR experiment will measure the spin structure functions for the sea quarks and gluons by measuring spin asymmetries in {ital W} and {ital Z} direct photon and jet productions. Sensitivity expectations are presented.

Download or read book Longitudinal Double spin Asymmetry and Cross Section for Inclusivejet Production in Polarized Proton Collisions at Sqrt s written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report a measurement of the longitudinal double-spinasymmetry A_LL and the differential cross section for inclusivemidrapidity jet production in polarized proton collisions at sqrt(s)=200GeV. The cross section data cover transverse momenta 5

Download or read book Longitudinal Double Spin Asymmetry in Inclusive Jet Production AtSTAR written by STAR Collaboration and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This contribution reports on the first measurement of the longitudinal double-spin asymmetry A{sub LL} for the inclusive production of jets in polarized proton-proton collisions at {radical}s = 200 GeV. The data were collected with STAR at RHIC in the years 2003 and 2004, and correspond to a sampled integrated luminosity of 0.3 pb{sup -1} with beam polarizations up to 45%. The results on A{sub LL} cover jet transverse momenta 5