Azimuthal anisotropy of direct photons in Au+Au collisions at βsNN=200GeV
Explore the source record for details and available documents.
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
Engineering topics
Drees, A.
Publications and source records attributed to Drees, A..
Determination of the sPHENIX background source with tracking
Explore the source record for details and available documents.
43 PARTICLE ACCELERATORSβ
EIC Interaction Region Magnet Design Overview
Explore the source record for details and available documents.
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
Erratum: Centrality-Dependent Modification of Jet-Production Rates in Deuteron-Gold Collisions at $\sqrt{π _{πβ’π}}$ = 200 GeV [Phys. Rev. Lett. 116, 122301 (2016)]
We previously reported jet-production rates in π + π and π + Au collisions at $\sqrt{π _{πβ’π}}$ = 200 GeV recorded in 2008 with the PHENIX detector at the Relativistic Heavy Ion Collider. Subsequently, we found that electronic noise in the electromagnetic calorimeter was not completely removed by the tower-timing cuts used in the analysis. We have conducted an independent re-analysis of the data that eliminated noisy towers by removing them completely from the analysis. These cuts remove any contributions from instrumental noise, but reduce the overall acceptance for electromagnetic clusters by β16% and hence the overall statistical power of the data. Finally, this re-analysis found that instrumental noise in the electromagnetic calorimeter led to an artificial increase in the jet yield for both the π + π and π + Au collisions.
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
Thermal Analysis and Simulations of the Abort Kicker Magnets Systems for the Electron-Ion Collider
The Abort Kicker Magnets system used in the current Relativistic Heavy Ion Collider (RHIC) to steer the circulating beam into the dump will be subjected to higher heat loads in the Electron-Ion Collider (EIC). After analyzing the existing abort kicker magnets and running thermal simulations in ANSYS it was concluded that they may not be suitable for use as-is in the future EIC due to heat and impedance concerns in the magnets. Possible solutions include adding a round titanium-coated ceramic beam tube to help solve the heat and impedance concerns, but this will reduce the limiting aperture of the kicker magnet. Another possible solution to meet all the performance requirements for EIC would be to add titanium-coated ceramic plates with water-cooling and tapered transitions that significantly improve the impedance and lower the heat in the magnets with less reduction to the aperture.
43 PARTICLE ACCELERATORSβ
Measurement of the 1-jettiness event shape observable in deep-inelastic electron-proton scattering at HERA
The H1 Collaboration reports the first measurement of the 1-jettiness event shape observable $Ο^b_1$ in neutral-current deep-inelastic electron-proton scattering (DIS). The observable $Ο^b_1$ is equivalent to a thrust observable defined in the Breit frame. The data sample was collected at the HERA ep collider in the years 2003β2007 with center-of-mass energy of $\sqrt{s}$ = 319 GeV, corresponding to an integrated luminosity of 351.1 pb -1 . Triple differential cross sections are provided as a function of $Ο^b_1$, event virtuality $Q^2$, and inelasticity y, in the kinematic region $Q^2$ > 150 GeV 2 . Single differential cross section are provided as a function of $Ο^b_1$ in a limited kinematic range. Double differential cross sections are measured, in contrast, integrated over $Ο^b_1$ and represent the inclusive neutral-current DIS cross section measured as a function of $Q^2$ and y. The data are compared to a variety of predictions and include classical and modern Monte Carlo event generators, predictions in fixed-order perturbative QCD where calculations up to $\mathcal{O}$($Ξ±^3_s$) are available for $Ο^b_1$ or inclusive DIS, and resummed predictions at next-to-leading logarithmic accuracy matched to fixed order predictions at $\mathcal{O}$($Ξ±^2_s$). These comparisons reveal sensitivity of the 1-jettiness observable to QCD parton shower and resummation effects, as well as the modeling of hadronization and fragmentation. Within their range of validity, the fixed-order predictions provide a good description of the data. Monte Carlo event generators are predictive over the full measured range and hence their underlying models and parameters can be constrained by comparing to the presented data.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDSβ
Measurement of groomed event shape observables in deep-inelastic electron-proton scattering at HERA
The H1 Collaboration at HERA reports the first measurement of groomed event shape observables in deep inelastic electron-proton scattering (DIS) at $\sqrt{s} =319$ GeV, using data recorded between the years 2003 and 2007 with an integrated luminosity of 351 pb -1 . Event shapes provide incisive probes of perturbative and non-perturbative QCD. Grooming techniques have been used for jet measurements in hadronic collisions; this paper presents the first application of grooming to DIS data. The analysis is carried out in the Breit frame, utilizing the novel Centauro jet clustering algorithm that is designed for DIS event topologies. Events are required to have squared momentum-transfer $Q^2 > 150$ GeV 2 and inelasticity $0.2< y < 0.7$. We report measurements of the production cross section of groomed event 1-jettiness and groomed invariant mass for several choices of grooming parameter. Monte Carlo model calculations and analytic calculations based on Soft Collinear Effective Theory are compared to the measurements.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDSβ
Observation and differential cross section measurement of neutral current DIS events with an empty hemisphere in the Breit frame
The Breit frame provides a natural frame to analyze leptonβproton scattering events. In this reference frame, the parton model hard interactions between a quark and an exchanged boson defines the coordinate system such that the struck quark is back-scattered along the virtual photon momentum direction. In Quantum Chromodynamics (QCD), higher order perturbative or non-perturbative effects can change this picture drastically. As Bjorken-x decreases below one half, a rather peculiar event signature is predicted with increasing probability, where no radiation is present in one of the two Breit-frame hemispheres and all emissions are to be found in the other hemisphere. At higher orders in $\alpha$ s or in the presence of soft QCD effects, predictions of the rate of these events are far from trivial, and that motivates measurements with real data. We report on the first observation of the empty current hemisphere events in electronβproton collisions at the HERA collider using data recorded with the H1 detector at a center-of-mass energy of 319 GeV. The fraction of inclusive neutral-current DIS events with an empty hemisphere is found to be 0.0112 Β± 3.9% stat Β± 4.5% syst Β± 1.6% mod in the selected kinematic region of 150 < Q 2 < 1500 GeV 2 and inelasticity 0.14 < y < 0.7. The data sample corresponds to an integrated luminosity of 351.1 pb -1 , sufficient to enable differential cross section measurements of these events. The results show an enhanced discriminating power at lower Bjorken-x among different Monte Carlo event generator predictions.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDSβ
Crossing transition in the EIC HSR with a resonance island jump scheme
The Resonance Island Jump (RIJ) scheme for transition crossing in the Hadron Storage Ring of the Electron-Ion Collider is radically new, and untested. Beam experiments in RHIC will be necessary if it becomes necessary to consider the RIJ scheme as a serious alternative to upgrading the first order linear jump scheme currently implemented in RHIC. This paper outlines the theoretical foundations of the RIJ scheme, and considers how a beam experiment in RHIC could be performed.
Accelerator Physicsβ
Identified charged-hadron production in π+Al, 3 He + Au, and Cu + Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and in U + U collisions at $\sqrt{s_{NN}}$ = 193 GeV
The PHENIX experiment has performed a systematic study of identified charged-hadron (π Β± , πΎ Β± , π, $\bar{π}$) production at midrapidity in π + Al, 3 He + Au, and Cu + Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and U + U collisions at $\sqrt{s_{NN}}$ = 193 GeV. Identified charged-hadron invariant transverse-momentum (π π ) and transverse-mass (π π ) spectra are presented and interpreted in terms of radially expanding thermalized systems. The particle ratios of πΎ/π and π/π have been measured in different centrality ranges of large (Cu + Au and U + U) and small (π + Al and 3 He + Au) collision systems. The values of πΎ/π ratios measured in all considered collision systems were found to be consistent with those measured in π+π collisions. However, the values of π/π ratios measured in large collision systems reach the values of β0.6, which is a factor of β2 larger than in π + π collisions. These results can be qualitatively understood in terms of the baryon enhancement expected from hadronization by recombination. Identified charged-hadron nuclear-modification factors (π π΄β’π΅ ) are also presented. Enhancement of proton π π΄β’π΅ values over meson π π΄β’π΅ values was observed in central 3 He + Au, Cu + Au, and U + U collisions. Finally, the proton π π΄β’π΅ values measured in the π + Al collision system were found to be consistent with π π΄β’π΅ values of π, π Β± , πΎ Β± , and π 0 mesons, which may indicate that the size of the system produced in π + Al collisions is too small for recombination to cause a noticeable increase in proton production.
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
Nonprompt direct-photon production in Au + Au collisions at $\sqrt{s_{NN}}$ = 200 GeV
The measurement of the direct-photon spectrum from Au + Au collisions at $\sqrt{s_{NN}}$ = 200 GeV is presented by the PHENIX Collaboration using the external-photon-conversion technique for 0%β93% central collisions in a transverse-momentum (π π ) range of 0.8β10 GeV/π. An excess of direct photons, above prompt-photon production from hard-scattering processes, is observed for π π < 6 GeV/π. Nonprompt direct photons are measured by subtracting the prompt component, which is estimated as π coll -scaled direct photons from π + π collisions at 200 GeV, from the direct-photon spectrum. Results are obtained for 0.8 < π π < 6.0 GeV/π and suggest that the spectrum has an increasing inverse slope from β0.2 to 0.4 GeV/π with increasing π π , which indicates a possible sensitivity of the measurement to photons from earlier stages of the evolution of the collision. In addition, like the direct-photon production, the π π -integrated nonprompt direct-photon yields also follow a power-law scaling behavior as a function of collision-system size. Finally, the exponent, πΌ, for the nonprompt component is found to be consistent with 1.1 with no apparent π π dependence.
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
Charm- and bottom-quark production in Au+Au collisions at $$ \sqrt{{\textrm{s}}_{\textrm{NN}}} $$=200 GeV
Here, the invariant yield of electrons from open-heavy-flavor decays for 1 < p T < 8 GeV/c at midrapidity |y| < 0.35 in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV has been measured by the PHENIX experiment at the Relativistic Heavy Ion Collider. A displaced-vertex analysis with the PHENIX silicon-vertex detector enables extraction of the fraction of charm and bottom hadron decays and unfolding of the invariant yield of parent charm and bottom hadrons. The nuclear-modification factors RAA for electrons from charm and bottom hadron decays and heavy-flavor hadrons show both a centrality and a quark-mass dependence, indicating suppression in the quark-gluon plasma produced in these collisions that is medium sized and quark-mass dependent.
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
Transverse single-spin asymmetry of charged hadrons at forward and backward rapidity in polarized p + p , p + Al , and p + Au collisions at s N N = 200 GeV
Not Available
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
Erratum: LΓ©vy-stable two-pion Bose-Einstein correlations in s N N = 200 GeV Au + Au collisions [Phys. Rev. C 97 , 064911 (2018)]
We previously published in 2018 a detailed measurement recorded in 2010 for Au+Au collisions at $\sqrt{^SNN}$ = 200 GeV of charged two-pion correlation functions in 0%-30% centrality. We found the data to be well described by Bose-Einstein correlation functions stemming from L$\acute{e}$vy-stable source distributions. Using a fine transverse momentum binning, we extracted the correlation strength parameter Ξ», the L$\acute{e}$vy index of stability Ξ± and the L$\acute{e}$vy length scale parameter R as a function of average transverse mass of the pair m T .
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
Measurement of Direct-Photon Cross Section and Double-Helicity Asymmetry at s = 510 GeV in p β + p β Collisions
Not Available
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
Transverse single-spin asymmetry of midrapidity Ο 0 and Ξ· mesons in p + Au and p + Al collisions at s N N = 200 GeV
Not Available
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
Improving constraints on gluon spin-momentum correlations in transversely polarized protons via midrapidity open-heavy-flavor electrons in p β + p collisions at s = 200 GeV
Not Available
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
HSR transition jump optics in the September 2022 layout
Transition is crossed during acceleration in the Hadron Storage Ring (HSR) for all species other than protons. A first-order transition jump scheme manipulates the value of the optical quantity Ξ³ T and distorts the optics of the HSR around the time that the beam energy Ξ³ beam crosses the nominal transition value Ξ³ T 0 . The jump scheme in the Relativistic Heavy Ion Collider (RHIC) uses 48 jump quads, driven by 12 bi-polar power supplies that each drive 4 quads in series. Ten of those 48 are eliminated in the preliminary September 2022 HSR layout (EIC-HSR-220921a) that was developed from RHIC with no initial regard for transition crossing. This note analyzes the performance of the 38-quad HSR scheme, by comparison with the 48-quad RHIC scheme. It is concerned only with optics β the manipulation and response of Twiss functions and related quantities β and not with beams. This evaluation is a necessary first step before enhancing the transition jump scheme to restore RHIC performance in the HSR. Eventually full beam simulations of transition crossing need to be performed.
43 PARTICLE ACCELERATORSβ