Download or read book Inclusive lambda Baryon Spectra in Au Au Collisions at Sqrt S NN written by Dillon Roach and published by . This book was released on 2015 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multi strange Baryon Production in Au Au Collisions at Sqrt sNN written by and published by . This book was released on 2003 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The transverse mass spectra and mid-rapidity yields for [Xi]s and [Omega]s plus their anti-particles are presented. The 10% most central collision yields suggest that the amount of multi-strange particles produced per produced charged hadron increases from SPS to RHIC energies. A hydrodynamically inspired model fit to the spectra, which assumes a thermalized source, seems to indicate that these multi-strange particles experience a significant transverse flow effect, but are emitted when the system is hotter and the flow is smaller than values obtained from a combined fit to [pi], K, p and [Lambda]s.

Download or read book High PT Inclusive Charged Hadron Spectra from Au Au Collisions at square Root s sub NN written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The STAR Collaboration presents new measurements of inclusive charged hadron distributions for p{sub T}

Download or read book High P sub Partial Inclusive Charged Hadron Distributions in Au Au Collisions at Square Root s sub NN written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis reports the measurement of the inclusive charged particle (h[sup+]+ h[sup -]) p[perpendicular] spectra for 1.7

Download or read book Schweitzerisches Kriegs Recht dem Publico er ffnet durch einen practicirten Secretarium written by and published by . This book was released on 1704 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scaling Properties of Hyperon Production in Au Au Collisions at Sqrt SNN written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the scaling properties of Lambda, Xi, and their anti-particles produced at mid-rapidity in Au+Au collisions at RHIC at psNN = 200 GeV. The yield of multi-strange baryons per participant nucleon increases from peripheral to central collisions more rapidly than the Lambda yield, which appears to correspond to an increasing strange quark density of matter produced. The value of the strange phase space occupancy factor gamma s, obtained from a thermal model fit to the data, approaches unity for the most central collisions. We also show that the nuclear modification factors, RCP, of Lambda and Xi are consistent with each other and with that of protons in the transverse momentum range2.0

Download or read book PROTON LAMBDA CORRELATIONS IN AU AU COLLISIONS AT SQUARE ROOT NN written by G. RENAULT and published by . This book was released on 2004 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The space-time evolution of the source of particles formed in the collision of nuclei can be studied through particle correlations. The STAR experiment is dedicated to study ultra-relativistic heavy ions collisions and allows to measure non-identical strange particle correlations. The source size can be extracted by studying p - {Lambda}, {bar p} - {bar {Lambda}}, {bar p} - {Lambda} and p - {bar {Lambda}} correlation functions. Strong interaction potential has been studied for these systems using an analytical model. Final State Interaction (FSI) parameters have been determined and has shown a significant annihilation process present in {bar p} - {Lambda} and p - {bar {Lambda}} systems not present in p - {Lambda} and {bar p} - {bar {Lambda}}.

Download or read book C AD Experiments 2000 2004 written by P. Lo Presti and published by . This book was released on 2004 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Baryon Spectra in Au Au Collisions written by and published by . This book was released on 1992 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multi strange Baryon Production in Au Au Collisions at s sub NN written by and published by . This book was released on 2003 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The transverse mass spectra and mid-rapidity yields for?s and?s plus their anti-particles are presented. The 10% most central collision yields suggest that the amount of multi-strange particles produced per produced charged hadron increases from SPS to RHIC energies. A hydrodynamically inspired model fit to the spectra, which assumes a thermalized source, seems to indicate that these multi-strange particles experience a significant transverse flow effect, but are emitted when the system is hotter and the flow is smaller than values obtained from a combined fit to?, K, p and?s.

Download or read book Pseudorapidity Asymmetry and Centrality Dependence of Charged Hadron Spectra in D Au Collisions at Sqrt sNN written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The pseudorapidity asymmetry and centrality dependence of charged hadron spectra in d+Au collisions at (square root)s{sub NN} = 200 GeV are presented. The charged particle density at mid-rapidity, its pseudorapidity asymmetry and centrality dependence are reasonably reproduced by a Multi-Phase Transport model, by HIJING, and by the latest calculations in a saturation model. Ratios of transverse momentum spectra between backward and forward pseudorapidity are above unity for p{sub T} below 5 GeV/c. The ratio of central to peripheral spectra in d+Au collisions shows enhancement at 2

Download or read book Baryon Spectra in Au Au Collisions written by and published by . This book was released on 1992 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements are presented of single particle spectra from Au targets using the recently commissioned Au-beam at 11.6 GeV/c per nucleon from the BNL Tandem-Booster-AGS accelerator facilities. Protons and deuterons were detected with the measuring the 25msr E-802 spectrometer. Collision centrality was determined by measuring the forward energy in a calorimeter subtending a 1.2° cone about 0°. Some comparisons with the cascade code ARC have been made.

Download or read book Non photonic Electron at High Transverse Momentum in Au Au Collisions and Bottom Quark Production in P p Collisions at Sqrt sNN written by Wenqin Xu and published by . This book was released on 2012 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new form of matter with de-confined quarks and gluons, named the "Quark Gluon Plasma" (QGP), is predicted by Lattice Qutantum Chromodynamics to exist at high temperatures and/or high baryon density regions in the QCD phase diagram. Experimental evidence indicates that the QCD matter created in high energy Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC) in Brookhaven National Lab is a strongly-coupled Quark-Gluon Plasma. One of the central goals of heavy ion physics is to understand the QGP through quantitative comparisons between theoretical calculations and experimental measurements. Heavy flavor quarks are believed to be a unique probe for this task, because they are dominantly produced in the initial hard scatterings, where the production rate can be well calculated by perturbative-QCD(pQCD). When heavy favor quarks traverse the QGP medium, they bear the imprints of the medium via their interactions with the medium. Dynamical models have been developed to calculate the interactions between heavy quarks and the QGP medium to quantitatively extract the medium properties. This dissertation presents a series of experimental studies with the electrons produced in the semi-leptonic decays of heavy flavor quarks in Au+Au and p+p collisions, which serve as the proxies for heavy flavor quarks. These electrons are referred to as non-photonic electrons (NPE), to be differentiated from the main background of photonic electrons. The production of NPE at high pT is found to be highly suppressed in central and semi-central Au+Au collisions, compared to binary-collision scaled production in p+p collisions. The azimuthal anisotropy of NPE is found to be finite at high pT, and the azimuthal correlation between high pT NPE and low pT hadrons exhibits a broadening in the away-side, both of which strengthen the evidence for a strong coupling between heavy flavor quarks and the QGP medium. In addition, the bottom quark production cross-section in p+p collisions is obtained based on the measured spectrum of NPE and the ratio of bottom/charm decay electrons.

Download or read book Study of Baryon Stopping Pion and Proton Production from 4 9 GeV Al Au Fixed target Collisions at STAR written by Todd Adler Kinghorn and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the goals of the Relativistic Heavy Ion Collider (RHIC) Beam Energy Scan program is to explore whether signatures of the quark-gluon plasma can be turned off, search for a potential Quantum-Chromodynamic (QCD) critical point, as well as identify the phase transition between hadronic and partonic matter. This program ran from the years 2010 through 2014 and certain observables such as the directed flow of protons and higher moments of net-protons show features that may suggest some sort of transition to hadron-dominated matter below 20 GeV. The Solenoidal Tracker at RHIC (STAR) Fixed-Target program was created to extend center of mass energies below [square root sNN]= 7.7 GeV, down to [square root sNN]= 3.0 GeV, as these energies are not practical to do with colliding beams at RHIC. This will be crucial in the second phase of the Beam Energy Scan program, BES-II, as data from energies within this range may yield information of the phase transition. The capabilities of reconstructing interactions with a fixed-target geometry needed to be demonstrated for the future of the program in BES-II. In 2015, two test runs with a fixed-target geometry were done with the STAR detector; the first was Au + Au at [square root sNN] = 4.5 GeV and the second, a month later, was Al + Au at [square root sNN] = 4.9 GeV center-of-mass energy. This dissertation focuses on the asymmetric Al + Au collisions but will involve mentions of the Au + Au run. In this work, the spectra and rapidity density of [pi]− and p are measured at the top 0-5%, 5-10%, 10-15%, 15-20%, 20-25%, and 25-30% most central collisions. In addition, the "stopping" for protons will be discussed.

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 A Measurement of Lambda hyperon Spin Polarization in Au Au Collisions at Sqrt s NN written by Joseph R. Adams (Nuclear physicist) and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-central collisions of relativistic atomic nuclei contain enormous angular momentum, $I\vec{J}I\sim\mathcal{O}(10^0-10^2\frac{\rm{TeV\cdot~fm}}{c}\approx10^3-10^5\hbar)$ in the collision energy range spanned by the capabilities of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Lab (BNL). The energy densities that exist in the collision interaction region are sufficient to deconfine constituent quarks from their bound nucleon states and thereby facilitate the short-lived ($\mathcal{O}(1\mathrm{fm}/c)$) formation of the so-called Quark-Gluon Plasma (QGP), to which some of the net $\vec{J}$ is transferred. The Solenoid Tracker At RHIC (STAR) is a set of detectors working in unison to reconstruct collision information, and is an indispensable tool used to study the QGP. I present here work surrounding $\vec{J}$, ranging from detector construction for STAR in order to accurately measure $\hat{J}$, experimental analysis of phenomena driven by $\vec{J}$ usig the STAR detector, and theoretical calculations involving the direction of $\vec{J}$ affected by event-by-event fluctuations. The "Event-Plane Detector" (EPD), after years of prototyping and design, was largely constructed at Ohio State University in 2017-2018 and officially replaced its predecessor, the Beam Beam Counter (BBC), at STAR. While similar detectors have been constructed, including the BBC, unique challenges were faced in the construction of the EPD. Due to many factors, including careful construction, the EPD's performance was and remains phenomenal, providing experimentalists in the STAR collaboration with far-improved resolution on $\hat{J}$. The use of the EPD was essential for drastically reducing the statistical uncertainties on a number of analyses, including the spin alignment of $\Lambda$ hyperons with $\hat{J}$, $\PLambda$. In this thesis is detailed the process of extracting the $\vec{J}$-driven $\PLambda$ at the relatively low center-of-momentum nucleon-nucleon collision energy of $\sNN=3$~GeV. In order to achieve such a low $\sNN$, the lowest yet achieved by RHIC, a "beam" of Au ions was made to hit a fixed Au foil target instead of two oppositely moving ion beams colliding; however, this fixed-target setup introduced numerous nuanced complications in order to extract $\PLambda$. A new experimental method to measure $\PLambda$ is introduced in this work to deal with such complicating details. I present here the observation of the largest yet-observed $\PLambda$ at the lowest $\sNN$ yet studied, as well as its dependences on event and $\Lambda$-hyperon kinematic variables. An inconclusive search for the magnetic field sustained in the QGP, $I\BQGPI$, is also presented here. While $\vec{J}$ drives $\PLambda$ as well as that of its anti-particle the $\bar{\Lambda}$ hyperons, $\PLamBar$, $\BQGP$ drives an enhancement of $\PLamBar$ and a suppression of $\PLambda$, leading to $\PLamBar-\PLambda$ splitting. This splitting has been observed in previous studies across a wide range of $\sNN$, but without sufficient statistical significance. A high-statistics data set at $\sNN=27$~GeV was performed by RHIC and collected by STAR which served as a promising tool to see a statistically significant splitting. The effort to measure the splitting at $\sNN=27$~GeV is briefly described in this thesis, but ultimately numerous complicated problems with the collider facility and the STAR detector presented nuanced dependences of the splitting; sufficient confidence could not be gained that unaccounted-for systematic effects would not be present. Also studied in this thesis were the effects of event-by-event nucleon-position fluctuations on the orientation of $\hat{J}$. Theoretical models of heavy-ion collisions were used to describe the positions of nucleons at the momentum of impact, as well as the time evolution of the system. Unsurprisingly, the directions of angular momentum of the nucleons (and deconfined quarks) that participated in the collision, $\JpartHat$, and that of the "spectator" nucleons, $\JspecHat$, fluctuate on an event-by-event basis due to the randomness inherent in the system. Theoretical calculations of $\PLambda$ correlate the $\Lambda$-hyperon spin with the angular momentum direction of the system, $\JsystHat$, and the function form of $\PLambda$ used to extract the signal experimentally uses the measurable $\JspecHat$ as an approximation of $\JsystHat$; however, we discover an additional decorrelation between $\Jspec$ and $\Jpart$ driven by conservation of angular momentum. More importantly, we find a much more significant decorrelation between $\Jspec$ and $\Jpart$ when looking at the more restricted region of particles used for measuring $\PLambda$, driven by random fluctuations. We also find, importantly, that this decorrelation becomes larger with increasing $\sNN$ and therefore serves as a crucial correction to apply to the observable $\PLambda$.

Download or read book Hadron Spectra in Au Au Collisions at the BNL AGS written by Michael David Heffner and published by . This book was released on 2000 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: