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Articles 31 - 60 of 667
Full-Text Articles in Astrophysics and Astronomy
Collision-Energy Dependence Of Deuteron Cumulanorrelations In Au+Au Collisions At Rhicts And Proton-Deuteron C, The Star Collaboration
Collision-Energy Dependence Of Deuteron Cumulanorrelations In Au+Au Collisions At Rhicts And Proton-Deuteron C, The Star Collaboration
Physics and Astronomy Faculty Publications
We report the first measurements of cumulants, up to 4𝑡ℎ order, of deuteron number distributions and proton-deuteron correlations in Au+Au collisions recorded by the STAR experiment in phase-I of Beam Energy Scan (BES) program at the Relativistic Heavy Ion Collider. Deuteron cumulants, their ratios, and proton-deuteron mixed cumulants are presented for different collision centralities covering a range of center-of-mass energy per nucleon pair √𝑠NN = 7.7 to 200 GeV. It is found that the cumulant ratios at lower collision energies favor a canonical ensemble over a grand canonical ensemble in thermal models. An anti-correlation between proton and deuteron multiplicity is …
Estimate Of Background Baseline And Upper Limit On The Chiral Magnetic Effect In Isobar Collisions At √S Nn = 200 Gev At The Bnl Relativistic Heavy Ion Collider, Star Collaboration
Estimate Of Background Baseline And Upper Limit On The Chiral Magnetic Effect In Isobar Collisions At √S Nn = 200 Gev At The Bnl Relativistic Heavy Ion Collider, Star Collaboration
Physics and Astronomy Faculty Publications
For the search of the chiral magnetic effect (CME), STAR previously presented the results from isobar collisions ( 96/44 Ru + 96/44 Ru, 96/40 Zr + 96/40 Zr) obtained through a blind analysis. The ratio of results in Ru + Ru to Zr + Zr collisions for the CME-sensitive charge-dependent azimuthal correlator (Δγ), normalized by elliptic anisotropy (v2 ), was observed to be close to but systematically larger than the inverse multiplicity ratio. The background baseline for the isobar ratio, Y = (Δγ /v2 )Ru (Δγ /v2 )Zr , is naively expected to be …
Exclusive J/Ψ, Ψ(2s), And E+E− Pair Production In Au + Au Ultraperipheral Collisions At The Bnl Relativistic Heavy Ion Collider, Star Collaboration
Exclusive J/Ψ, Ψ(2s), And E+E− Pair Production In Au + Au Ultraperipheral Collisions At The Bnl Relativistic Heavy Ion Collider, Star Collaboration
Physics and Astronomy Faculty Publications
Measurements of exclusive J/ψ, ψ (2s), and electron-positron (e+e−) pair photoproduction in Au + Au ultraperipheral collisions are reported by the STAR experiment at √sNN = 200 GeV. We report several first measurements at the BNL Relativistic Heavy Ion Collider, which are (i) J/ψ photoproduction with large momentum transfer up to 2.2 (GeV/c)2 , (ii) coherent J/ψ photoproduction associated with neutron emissions from nuclear breakup, (iii) the rapidity dependence of incoherent J/ψ photoproduction, (iv) the ψ (2s) photoproduction cross section at midrapidity, and (v) e+e− pair photoproduction up to high invariant mass of 6 GeV/c2 . For measurement (ii), the …
Jet-Hadron Correlations With Respect To The Event Plane In √S Nn = 200 Gev Au + Au Collisions In Star, Star Collaboration
Jet-Hadron Correlations With Respect To The Event Plane In √S Nn = 200 Gev Au + Au Collisions In Star, Star Collaboration
Physics and Astronomy Faculty Publications
Angular distributions of charged particles relative to jet axes are studied in √s NN = 200 GeV Au+Au collisions as a function of the jet orientation with respect to the event plane. This differential study tests the expected path-length dependence of energy loss experienced by a hard-scattered parton as it traverses the hot and dense medium formed in heavy-ion collisions. A second-order event plane is used in the analysis as an experimental estimate of the reaction plane formed by the collision impact parameter and the beam direction. Charged-particle jets with 15 < pT,jet < 20 and 20 < pT,jet < 40 GeV/c were reconstructed with the anti-kT algorithm with radius parameter setting of R = 0.4 in the 20–50% centrality bin to maximize the initial-state eccentricity of the interaction region. The reaction plane fit method is implemented to remove the flow-modulated background with better precision than prior methods. Yields and widths of jet-associated charged-hadron distributions are extracted in three angular bins between the jet axis and the event plane. The event-plane (EP) dependence is further quantified by ratios of the associated yields in different EP bins. No dependence on orientation of the jet axis with respect to the event plane is seen within the uncertainties in the kinematic regime studied. This finding is consistent with a similar experimental observation by ALICE in √s NN = 2.76 TeV Pb-Pb collision data.
Measurements Of Charged-Particle Multiplicity Dependence Of Higher-Order Net-Proton Cumulants In 𝑝+𝑝 Collisions At √𝑠 = 200 Gev From Star At Rhic, Star Collaboration
Measurements Of Charged-Particle Multiplicity Dependence Of Higher-Order Net-Proton Cumulants In 𝑝+𝑝 Collisions At √𝑠 = 200 Gev From Star At Rhic, Star Collaboration
Physics and Astronomy Faculty Publications
We report on the charged-particle multiplicity dependence of net-proton cumulant ratios up to sixth order from√𝑠 = 200 GeV 𝑝+𝑝 collisions at the Relativistic Heavy Ion Collider (RHIC). The measured ratios 𝐶4 ∕𝐶2, 𝐶5 ∕𝐶1, and 𝐶6 ∕𝐶2 decrease with increased charged-particle multiplicity and rapidity acceptance. Neither the Skellam baselines nor PYTHIA8 calculations account for the observed multiplicity dependence. In addition, the ratios 𝐶5 ∕𝐶1 and 𝐶6 ∕𝐶2 approach negative values in the highest-multiplicity events, which implies that thermalized QCD matter may be formed in 𝑝+𝑝 collisions.
Measurements Of The 𝑍0 ∕𝛾∗ Cross Section And Transverse Single Spin Asymmetry In 510 Gev 𝑝+𝑝 Collisions, The Star Collaboration
Measurements Of The 𝑍0 ∕𝛾∗ Cross Section And Transverse Single Spin Asymmetry In 510 Gev 𝑝+𝑝 Collisions, The Star Collaboration
Physics and Astronomy Faculty Publications
The differential cross section for 𝑍0 production, measured as a function of the boson’s transverse momentum (𝑝T), provides important constraints on the evolution of the transverse momentum dependent parton distribution functions (TMDs). The transverse single spin asymmetry (TSSA) of the 𝑍0 is sensitive to one of the polarized TMDs, the Sivers function, which is predicted to have the opposite sign in 𝑝 + 𝑝 → 𝑊 ∕𝑍 + 𝑋 from that which enters in semi-inclusive deep inelastic scattering. In this Letter, the STAR Collaboration reports the first measurement of the 𝑍0 ∕𝛾∗ differential cross section as a function of its …
Measurement Of Flow Coefficients In High-Multiplicity P + Au, D + Au, And 3 He + Au Collisions At √S Nn = 200 Gev, Star Collaboration
Measurement Of Flow Coefficients In High-Multiplicity P + Au, D + Au, And 3 He + Au Collisions At √S Nn = 200 Gev, Star Collaboration
Physics and Astronomy Faculty Publications
Flow coefficients (v2 and v3 ) are measured in high-multiplicity p + Au, d + Au, and 3 He + Au collisions at a center-of-mass energy of √s NN = 200 GeV using the STAR detector. The measurements utilize two-particle correlations with a pseudorapidity requirement of |η| < 0.9 and a pair gap of |Δη| > 1.0. The primary focus is on analysis methods, particularly the subtraction of nonflow contributions. Four established nonflow subtraction methods are applied to determine vn, validated using the HIJING event generator. vn values are compared across the three collision systems at similar multiplicities; this comparison cancels the final-state effects and isolates the …
Reaction Plane Correlated Triangular Flow In Au+Au Collisions At √S Nn = 3 Gev, Star Collaboration
Reaction Plane Correlated Triangular Flow In Au+Au Collisions At √S Nn = 3 Gev, Star Collaboration
Physics and Astronomy Faculty Publications
We measure triangular flow relative to the reaction plane at 3 GeV center-of-mass energy in Au+Au collisions at the BNL Relativistic Heavy Ion Collider. A significant v3 signal for protons is observed, which increases for higher rapidity, higher transverse momentum, and more peripheral collisions. The triangular flow is essentially rapidity-odd with a slope at midrapidity, dv3/dy|(y=0), opposite in sign compared to the slope for directed flow. No significant v3 signal is observed for charged pions and kaons. Comparisons with models suggest that a mean field potential is required to describe these results, and that the triangular shape of the participant …
Results On Elastic Cross Sections In Proton–Proton Collisions At √𝑠 = 510 Gev With The Star Detector At Rhic, The Star Collaboration
Results On Elastic Cross Sections In Proton–Proton Collisions At √𝑠 = 510 Gev With The Star Detector At Rhic, The Star Collaboration
Physics and Astronomy Faculty Publications
We report results on an elastic cross section measurement in proton–proton collisions at a center-of-mass energy√𝑠 = 510 GeV, obtained with the Roman Pot setup of the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The elastic differential cross section is measured in the four-momentum transfer squared range 0.23 ≤ −𝑡 ≤ 0.67 GeV2. This is the only measurement of the proton-proton elastic cross section in this 𝑡 range for collision energies above the Intersecting Storage Rings (ISR) and below the Large Hadron Collider (LHC) colliders. We find that a constant slope 𝐵 does not fit the data in …
Upper Limit On The Chiral Magnetic Effect In Isobar Collisions At The Relativistic Heavy-Ion Collider, Star Collaboration
Upper Limit On The Chiral Magnetic Effect In Isobar Collisions At The Relativistic Heavy-Ion Collider, Star Collaboration
Physics and Astronomy Faculty Publications
The chiral magnetic effect (CME) is a phenomenon that arises from the QCD anomaly in the presence of an external magnetic field. The experimental search for its evidence has been one of the key goals of the physics program of the Relativistic Heavy-Ion Collider. The STAR Collaboration has previously presented the results of a blind analysis of isobar collisions (96 44 Ru + 96 44 Ru, 96 40 Zr + 96 40 Zr) in the search for the CME. The isobar ratio (Y ) of CME-sensitive observable, charge separation scaled by elliptic anisotropy, is close to but systematically larger than …
Production Of Protons And Light Nuclei In Au+Au Collisions At √S Nn = 3 Gev With The Star Detector, Star Collaboration
Production Of Protons And Light Nuclei In Au+Au Collisions At √S Nn = 3 Gev With The Star Detector, Star Collaboration
Physics and Astronomy Faculty Publications
We report the systematic measurement of protons and light nuclei production in Au+Au collisions at √s NN = 3 GeV by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The transverse momentum (pT ) spectra of protons (p), deuterons (d), tritons (t), 3 He, and 4 He have been measured from midrapidity to target rapidity for different collision centralities. We present the rapidity and centrality dependence of particle yields (dN/dy), average transverse momentum (〈pT 〉), yield ratios (d/p, t/p, 3 He /p, 4 He /p), as well as the coalescence parameters (B2 , B3 ). The 4π yields …
Microstructural, Mineralogical, And Chemical Characterization Of The Handys Bend And Flax Creek Meteorites, Kentucky: Relevance For The Iron Meteorite Record, Ethan S.L. Davis
Microstructural, Mineralogical, And Chemical Characterization Of The Handys Bend And Flax Creek Meteorites, Kentucky: Relevance For The Iron Meteorite Record, Ethan S.L. Davis
Theses and Dissertations--Earth and Environmental Sciences
Iron meteorites remain the only material view into planetary cores. Despite their scientific relevance, iron meteorites are relatively rare. In June 2021 and March 2022, the Kentucky Geological Survey received requests to identify two metallic specimens discovered in central Kentucky. The specimens were given the provisional names Handys Bend (3175.2 g) and Flax Creek (286.2 g). The goal of this project is to confirm meteoritic origin, characterize their structures and chemistry, assign genetic classifications, and examine potential relations to previous discoveries. Petrography was conducted using scanning electron microscopy. Mineral phases were examined using X-Ray diffraction crystallography. Chemical compositions were determined …
Performance Optimization For A Scintillating Glass Electromagnetic Calorimeter At The Eic, J. Crafts, Renee H. Fatemi, T. Horn, D. Kalinkin
Performance Optimization For A Scintillating Glass Electromagnetic Calorimeter At The Eic, J. Crafts, Renee H. Fatemi, T. Horn, D. Kalinkin
Physics and Astronomy Faculty Publications
The successful realization of the EIC scientific program requires the design and construction of high-performance particle detectors. Recent developments in the field of scientific computing and increased availability of high performance computing resources have made it possible to perform optimization of multi-parameter designs, even when the latter require longer computational times (for example simulations of particle interactions with matter). Procedures involving machine-assisted techniques used to inform the design decision have seen a considerable growth in popularity among the EIC detector community. Having already been realized for tracking and RICH PID detectors, it has a potential application in calorimetry designs. A …
Exploring The Hot And Gaseous Universe From Infrared To X-Ray, Chamani Gunasekera
Exploring The Hot And Gaseous Universe From Infrared To X-Ray, Chamani Gunasekera
Theses and Dissertations--Physics and Astronomy
Over 90% of baryonic matter in the universe exists as astrophysical plasmas. The gas
is often far from thermodynamic equilibrium, so numerical non-equilibrium spectral
synthesis simulations are used to understand observations. cloudy simulates vari-
ous physical conditions, providing spectra predictions. This thesis aims to meet the
challenge of new observatories like the JWST (James Webb Space Telescope) and
XRISM (X-Ray Imaging Spectroscopy Mission). These simulations are no better
than the underlying atomic and molecular database and the fourth chapter details
a long-needed update to an evolving database. The predicted spectra are strongly
affected by the composition of the gas, which …
Spinning Spheroidal Components Of Disk Galaxies: Resonant Interactions With Stellar Bars, Xingchen Li
Spinning Spheroidal Components Of Disk Galaxies: Resonant Interactions With Stellar Bars, Xingchen Li
Theses and Dissertations--Physics and Astronomy
The majority of disk galaxies possess stellar bars, which are the main driver in the internal evolution of barred galaxies. Bars represent non-axisymmetric perturbations in the galactic disks, producing strong gravitational torques that facilitate angular momentum transfer from the disk to the spheroidal components, such as central stellar bulges and host dark matter (DM) halos. The redistribution of angular momentum in barred galaxies proceeds mainly via resonant interactions between the bar and orbits in the spheroids. The amount of angular momentum emitted or absorbed at each resonance depends on the mass distribution, density and spin in the spheroidal components. Thus, …
Jwst/Nirspec Measurements Of The Relationships Between Nebular Emission-Line Ratios And Stellar Mass At Z ∼ 3–6, Alice E. Shapley, Naveen Reddy, Ryan L. Sanders, Michael W. Topping, Gabriel B. Brammer
Jwst/Nirspec Measurements Of The Relationships Between Nebular Emission-Line Ratios And Stellar Mass At Z ∼ 3–6, Alice E. Shapley, Naveen Reddy, Ryan L. Sanders, Michael W. Topping, Gabriel B. Brammer
Physics and Astronomy Faculty Publications
We analyze the rest-optical emission-line ratios of star-forming galaxies at 2.7 ≤ z < 6.5 drawn from the Cosmic Evolution Early Release Science (CEERS) Survey and their relationships with stellar mass (M *). Our analysis includes both line ratios based on the [N ii] λ6583 feature ([N ii] λ6583/Hα, ([O iii] λ5007/Hβ)/([N ii] λ6583/Hα) (O3N2), and [N ii] λ6583/[O ii] λ3727) and those featuring α-elements ([O iii] λ5007/Hβ, [O iii] λ5007/[O ii] λ3727 (O32), ([O iii] λλ4959, 5007 + [O ii] λ3727)/Hβ (R23), and [Ne iii] λ3869/[O ii] λ3727). Given the typical flux levels of [N ii] λ6583 and [Ne iii] λ3869, which are undetected in the majority of individual CEERS galaxies at 2.7 …
Higher-Order Cumulants And Correlation Functions Of Proton Multiplicity Distributions In √Snn = 3 Gev Au+Au Collisions At The Rhic Star Experiment, The Star Collaboration
Higher-Order Cumulants And Correlation Functions Of Proton Multiplicity Distributions In √Snn = 3 Gev Au+Au Collisions At The Rhic Star Experiment, The Star Collaboration
Physics and Astronomy Faculty Publications
We report a measurement of cumulants and correlation functions of event-by-event proton multiplicity distributions from fixed-target Au+Au collisions at √sNN = 3 GeV measured by the STAR experiment. Protons are identified within the rapidity (y) and transverse momentum (pT ) region −0.9 < y < 0 and 0.4 < pT < 2.0 GeV/c in the center-of-mass frame. A systematic analysis of the proton cumulants and correlation functions up to sixth order as well as the corresponding ratios as a function of the collision centrality, pT , and y are presented. The effect of pileup and initial volume fluctuations on these observables and the respective corrections are discussed in detail. The results are compared to calculations from the hadronic transport UrQMD model as well as a hydrodynamic model. In the most central 5% collisions, the value of proton cumulant ratio C4/C2 is negative, drastically different from the values observed in Au+Au collisions at higher energies. Compared to model calculations including lattice QCD, a hadronic transport model, and a hydrodynamic model, the strong suppression in the ratio of C4/C2 at 3 GeV Au+Au collisions indicates an energy regime dominated by hadronic interactions.
Azimuthal Anisotropy Measurement Of (Multi)Strange Hadrons In Au+Au Collisions At √S Nn = 54.4 Gev, Star Collaboration
Azimuthal Anisotropy Measurement Of (Multi)Strange Hadrons In Au+Au Collisions At √S Nn = 54.4 Gev, Star Collaboration
Physics and Astronomy Faculty Publications
Azimuthal anisotropy of produced particles is one of the most important observables used to access the collective properties of the expanding medium created in relativistic heavy-ion collisions. In this paper, we present second (v2) and third (v3) order azimuthal anisotropies of KS0, φ, Λ, Ξ, and ω at midrapidity (|y|< 1) in Au+Au collisions at sNN=54.4 GeV measured by the STAR detector. The v2 and v3 are measured as a function of transverse momentum and centrality. Their energy dependence is also studied. v3 is found to be more sensitive to the change in the center-of-mass energy than v2. Scaling by constituent quark number is found to hold for v2 within 10%. This observation could be evidence for the development of partonic collectivity in 54.4 GeV Au+Au collisions. Differences in v2 and v3 between baryons and antibaryons are presented, and ratios of v3/v23/2 are studied and motivated by hydrodynamical calculations. The ratio of v2 of φ mesons to that of antiprotons [v2(φ)/v2(p¯)] shows centrality dependence at low transverse momentum, presumably resulting from the larger effects from hadronic interactions on antiproton v2.
Gauging The Mass Of Metals In The Gas Phase Of Galaxies From The Local Universe To The Epoch Of Reionization, K. E. Heintz, Alice E. Shapley, Ryan L. Sanders, M. Killi, D. Watson, G. Magdis, F. Valentino, M. Ginolfi, D. Narayanan, T. R. Greve, J. P. U. Fynbo, D. Vizgan, S. N. Wilson
Gauging The Mass Of Metals In The Gas Phase Of Galaxies From The Local Universe To The Epoch Of Reionization, K. E. Heintz, Alice E. Shapley, Ryan L. Sanders, M. Killi, D. Watson, G. Magdis, F. Valentino, M. Ginolfi, D. Narayanan, T. R. Greve, J. P. U. Fynbo, D. Vizgan, S. N. Wilson
Physics and Astronomy Faculty Publications
The chemical enrichment of dust and metals are vital processes in constraining the star formation history of the universe. These are important ingredients in the formation and evolution of galaxies overall. Previously, the dust masses of high-redshift star-forming galaxies have been determined through their far-infrared continuum, however, equivalent, and potentially simpler, approaches to determining the metal masses have yet to be explored at z ≳ 2. Here, we present a new method of inferring the metal mass in the interstellar medium (ISM) of galaxies out to z 8, using the far-infrared [C II]- 158† μm emission line as a proxy. …
Jwst/Nirspec Balmer-Line Measurements Of Star Formation And Dust Attenuation At Z ∼ 3–6, Alice E. Shapley, Ryan L. Sanders, Naveen Reddy, Michael W. Topping, Gabriel B. Brammer
Jwst/Nirspec Balmer-Line Measurements Of Star Formation And Dust Attenuation At Z ∼ 3–6, Alice E. Shapley, Ryan L. Sanders, Naveen Reddy, Michael W. Topping, Gabriel B. Brammer
Physics and Astronomy Faculty Publications
We present an analysis of the star formation rates (SFRs) and dust attenuation properties of star-forming galaxies at 2.7 ≤ z < 6.5 drawn from the Cosmic Evolution Early Release Science Survey. Our analysis is based on JWST/NIRSpec Micro-Shutter Assembly R ∼ 1000 spectroscopic observations covering approximately 1-5 μm. Our primary rest-frame optical spectroscopic measurements are Hα/Hβ Balmer decrements, which we use as an indicator of nebular dust attenuation. In turn, we use Balmer decrements to obtain dust-corrected Hα-based SFRs (i.e., SFR(Hα)). We construct the relationship between SFR(Hα) and stellar mass (M *) in three bins of redshift (2.7 ≤ z < 4.0, 4.0 ≤ z < 5.0, and 5.0 ≤ z < 6.5), which represents the first time the star-forming main sequence has been traced at these redshifts using direct spectroscopic measurements of Balmer emission as a proxy for SFR. In tracing the relationship between SFR(Hα) and M * back to such early times (z > 3), it is essential to use a conversion factor between Hα and SFR that accounts for the subsolar metallicity prevalent among distant galaxies. We also use measured Balmer decrements to investigate the relationship between dust attenuation and stellar mass out to z ∼ 6. The lack of significant redshift evolution in attenuation at fixed stellar mass, previously confirmed using Balmer decrements out …
Azimuthal Anisotropy Measurement Of (Multi)Strange Hadrons In Au+Au Collisions At √𝑠𝑁𝑁=54.4 Gev, Star Collaboration
Azimuthal Anisotropy Measurement Of (Multi)Strange Hadrons In Au+Au Collisions At √𝑠𝑁𝑁=54.4 Gev, Star Collaboration
Physics and Astronomy Faculty Publications
Azimuthal anisotropy of produced particles is one of the most important observables used to access the collective properties of the expanding medium created in relativistic heavy-ion collisions. In this paper, we present second (v2) and third (v3) order azimuthal anisotropies of KS0, φ, Λ, Ξ, and ω at midrapidity (|y|< 1) in Au+Au collisions at sNN=54.4 GeV measured by the STAR detector. The v2 and v3 are measured as a function of transverse momentum and centrality. Their energy dependence is also studied. v3 is found to be more sensitive to the change in the center-of-mass energy than v2. Scaling by constituent quark number is found to hold for v2 within 10%. This observation could be evidence for the development of partonic collectivity in 54.4 GeV Au+Au collisions. Differences in v2 and v3 between baryons and antibaryons are presented, and ratios of v3/v23/2 are studied and motivated by hydrodynamical calculations. The ratio of v2 of φ mesons to that of antiprotons [v2(φ)/v2(p¯)] shows centrality dependence at low transverse momentum, presumably resulting from the larger effects from hadronic interactions on antiproton v2.
Beam Energy Dependence Of Fifth- And Sixth-Order Net-Proton Number Fluctuations In Au + Au Collisions At Rhic, Star Collaboration
Beam Energy Dependence Of Fifth- And Sixth-Order Net-Proton Number Fluctuations In Au + Au Collisions At Rhic, Star Collaboration
Physics and Astronomy Faculty Publications
We report the beam energy and collision centrality dependence of fifth and sixth order cumulants (C5, C6) and factorial cumulants (κ5, κ6) of net-proton and proton number distributions, from center-of-mass energy (sNN) 3 GeV to 200 GeV Au+Au collisions at RHIC. Cumulant ratios of net-proton (taken as proxy for net-baryon) distributions generally follow the hierarchy expected from QCD thermodynamics, except for the case of collisions at 3 GeV. The measured values of C6/C2 for 0%-40% centrality collisions show progressively negative trend with decreasing energy, while it is positive for the lowest energy studied. These observed negative signs are consistent with …
Measurement Of Sequential ϒ Suppression In Au + Au Collisions At √Snn = 200 Gev With The Star Experiment, Star Collaboration
Measurement Of Sequential ϒ Suppression In Au + Au Collisions At √Snn = 200 Gev With The Star Experiment, Star Collaboration
Physics and Astronomy Faculty Publications
We report on measurements of sequential ϒ suppression in Au+Au collisions at sNN=200 GeV with the STAR detector at the Relativistic Heavy Ion Collider (RHIC) through both the dielectron and dimuon decay channels. In the 0%-60% centrality class, the nuclear modification factors (RAA), which quantify the level of yield suppression in heavy-ion collisions compared to p+p collisions, for ϒ(1S) and ϒ(2S) are 0.40±0.03(stat)±0.03(sys)±0.09(norm) and 0.26±0.08(stat)±0.02(sys)±0.06(norm), respectively, while the upper limit of the ϒ(3S) RAA is 0.17 at a 95% confidence level. This provides experimental evidence that the ϒ(3S) is significantly more suppressed than the ϒ(1S) at RHIC. The level of …
Measurementus Magnetic Moment To 0.20 Ppm Of The Positive Muon Anomalo, The Muon G − 2 Collaboration
Measurementus Magnetic Moment To 0.20 Ppm Of The Positive Muon Anomalo, The Muon G − 2 Collaboration
Physics and Astronomy Faculty Publications
We present a new measurement of the positive muon magnetic anomaly, aμ(gμ-2)/2, from the Fermilab Muon g-2 Experiment using data collected in 2019 and 2020. We have analyzed more than 4 times the number of positrons from muon decay than in our previous result from 2018 data. The systematic error is reduced by more than a factor of 2 due to better running conditions, a more stable beam, and improved knowledge of the magnetic field weighted by the muon distribution, p′, and of the anomalous precession frequency corrected for beam dynamics effects, ωa. From the ratio ωa/p′, together with precisely …
Ai-Assisted Optimization Of The Ecce Tracking System At The Electron Ion Collider, C. Fanelli, Z. Papandreou, K. Suresh
Ai-Assisted Optimization Of The Ecce Tracking System At The Electron Ion Collider, C. Fanelli, Z. Papandreou, K. Suresh
Physics and Astronomy Faculty Publications
The Electron-Ion Collider (EIC) is a cutting-edge accelerator facility that will study the nature of the ‘‘glue’’ that binds the building blocks of the visible matter in the universe. The proposed experiment will be realized at Brookhaven National Laboratory in approximately 10 years from now, with detector design and R&D currently ongoing. Notably, EIC is one of the first large-scale facilities to leverage Artificial Intelligence (AI) already starting from the design and R&D phases. The EIC Comprehensive Chromodynamics Experiment (ECCE) is a consortium that proposed a detector design based on a 1.5 T solenoid. The EIC detector proposal review concluded …
Scientific Computing Plan For The Ecce Detector At The Electron Ion Collider, J. C. Bernauer, C. T. Dean, C. Fanelli, J. Huang, K. Kauder, D. Lawrence, J. D. Osborn
Scientific Computing Plan For The Ecce Detector At The Electron Ion Collider, J. C. Bernauer, C. T. Dean, C. Fanelli, J. Huang, K. Kauder, D. Lawrence, J. D. Osborn
Physics and Astronomy Faculty Publications
The Electron Ion Collider (EIC) is the next generation of precision QCD facility to be built at Brookhaven National Laboratory in conjunction with Thomas Jefferson National Laboratory. There are a significant number of software and computing challenges that need to be overcome at the EIC. During the EIC detector proposal development period, the ECCE consortium began identifying and addressing these challenges in the process of producing a complete detector proposal based upon detailed detector and physics simulations. In this document, the software and computing efforts to produce this proposal are discussed; furthermore, the computing and software model and resources required …
Paschen-Line Constraints On Dust Attenuation And Star Formation At Z ∼ 1–3 With Jwst/ Nirspec, Naveen Reddy, Michael W. Topping, Ryan L. Sanders, Alice E. Shapley, Gabriel B. Brammer
Paschen-Line Constraints On Dust Attenuation And Star Formation At Z ∼ 1–3 With Jwst/ Nirspec, Naveen Reddy, Michael W. Topping, Ryan L. Sanders, Alice E. Shapley, Gabriel B. Brammer
Physics and Astronomy Faculty Publications
We use medium-resolution JWST/NIRSpec observations from the Cosmic Evolution Early Release Science Survey to place the first constraints on dust attenuation and star formation based on Paschen lines for a sizable sample of 63 galaxies at redshifts z = 1.0-3.1. Our analysis indicates strong correlations between the Balmer decrement, Hα/Hβ, and line ratios that include Paschen lines (i.e., Paα/Hβ, Paβ/Hβ, and the Paschen decrement, Paα/Paβ), suggesting that the former is sensitive to the overall dust obscuration toward H ii regions in high-redshift galaxies. The line ratios are used to derive nebular reddening, E(B − V)neb, and star formation …
The Gas And Stellar Content Of A Metal-Poor Galaxy At Z = 8.496 As Revealed By Jwst And Alma, K. E. Heintz, C. Giménez-Arteaga, S. Fujimoto, Gabriel B. Brammer, D. Espada, S. Gillman, J. González-López, T. R. Greve, Yuichi Harikane, B. Hatsukade, K. K. Knudsen, Anton M. Koekemoer, K. Kohno, V. Kokorev, M. M. Lee, Georgios E. Magdis, E. J. Nelson, F. Rizzo, Ryan L. Sanders, D. Schaerer, Alice E. Shapley, V. B. Strait, S. Toft, F. Valentino, A. Van Der Wel, A. P. Vijayan, D. Watson, F. E. Bauer, Amber Christiansen, C. R. Christiansen, S. N. Wilson
The Gas And Stellar Content Of A Metal-Poor Galaxy At Z = 8.496 As Revealed By Jwst And Alma, K. E. Heintz, C. Giménez-Arteaga, S. Fujimoto, Gabriel B. Brammer, D. Espada, S. Gillman, J. González-López, T. R. Greve, Yuichi Harikane, B. Hatsukade, K. K. Knudsen, Anton M. Koekemoer, K. Kohno, V. Kokorev, M. M. Lee, Georgios E. Magdis, E. J. Nelson, F. Rizzo, Ryan L. Sanders, D. Schaerer, Alice E. Shapley, V. B. Strait, S. Toft, F. Valentino, A. Van Der Wel, A. P. Vijayan, D. Watson, F. E. Bauer, Amber Christiansen, C. R. Christiansen, S. N. Wilson
Physics and Astronomy Faculty Publications
We present a joint analysis of the galaxy S04590 at z = 8.496 based on NIRSpec, NIRCam, and NIRISS observations obtained as part of the Early Release Observations program of the James Webb Space Telescope (JWST) and the far-infrared [C ii] 158 μm emission line detected by dedicated Atacama Large Millimeter/submillimeter Array (ALMA) observations. We determine the physical properties of S04590 from modeling of the spectral energy distribution (SED) and through the redshifted optical nebular emission lines detected with JWST/NIRSpec. The best-fit SED model reveals a low-mass (M ⋆ = 107.2-108 M ⊙) galaxy with a …
A Jwst/Nirspec Exploration Of The Connection Between Ionization Parameter, Electron Density, And Star-Formation-Rate Surface Density In Z = 2.7–6.3 Galaxies, Naveen Reddy, Michael W. Topping, Ryan L. Sanders, Alice E. Shapley, Gabriel B. Brammer
A Jwst/Nirspec Exploration Of The Connection Between Ionization Parameter, Electron Density, And Star-Formation-Rate Surface Density In Z = 2.7–6.3 Galaxies, Naveen Reddy, Michael W. Topping, Ryan L. Sanders, Alice E. Shapley, Gabriel B. Brammer
Physics and Astronomy Faculty Publications
We examine the factors responsible for the variation in the ionization parameter (U) of high-redshift star-forming galaxies based on medium-resolution JWST/NIRSpec observations obtained by the Cosmic Evolution Early Release Science survey. The sample consists of 48 galaxies with redshifts zspec = 2.7−6.3, which are largely representative of typical galaxies at these redshifts. The [S II] λλ6718, 6733 doublet is used to estimate electron densities (n e), and dust-corrected Hα luminosities are used to compute ionizing photon rates (Q). Using composite spectra of galaxies in bins of [O III] λλ4960, 5008/[O II] λλ3727, 3730 (O32) as a proxy for U, we …
An Updated Dust-To-Star Geometry: Dust Attenuation Does Not Depend On Inclination In 1.3 <= Z <= 2.6 Star-Forming Galaxies From Mosdef, Brian Lorenz, Mariska Kriek, Alice E. Shapley, Naveen Reddy, Ryan L. Sanders, Guillermo Barro, Alison L. Coil, Bahram Mobasher, Sedona H. Price, Jordan N. Runco, Irene Shivaei, Brian Siana, Daniel R. Weisz
An Updated Dust-To-Star Geometry: Dust Attenuation Does Not Depend On Inclination In 1.3 <= Z <= 2.6 Star-Forming Galaxies From Mosdef, Brian Lorenz, Mariska Kriek, Alice E. Shapley, Naveen Reddy, Ryan L. Sanders, Guillermo Barro, Alison L. Coil, Bahram Mobasher, Sedona H. Price, Jordan N. Runco, Irene Shivaei, Brian Siana, Daniel R. Weisz
Physics and Astronomy Faculty Publications
We investigate dust attenuation and its dependence on viewing angle for 308 star-forming galaxies at 1.3 < = z < = 2.6 from the MOSFIRE Deep Evolution Field survey. We divide galaxies with a detected Hα emission line and coverage of Hβ into eight groups by stellar mass, star formation rate (SFR), and inclination (i.e., axis ratio), and we then stack their spectra. From each stack, we measure the Balmer decrement and gas-phase metallicity, and then we compute the median AV and UV continuum spectral slope (β). First, we find that none of the dust properties (Balmer decrement, AV , or β) varies with the axis ratio. Second, both stellar and nebular attenuation increase with increasing galaxy mass, showing little residual dependence on SFR or metallicity. Third, nebular emission is more attenuated than stellar emission, and this difference grows even larger at higher galaxy masses and SFRs. Based on these results, we propose a three-component dust model in which attenuation predominantly occurs in star-forming regions and large, dusty star-forming clumps, with minimal attenuation in the diffuse ISM. In this model, nebular attenuation primarily originates in clumps, while stellar attenuation is dominated by star-forming regions. Clumps become larger and more common with increasing galaxy mass, creating the above mass trends. Finally, we argue that a fixed metal yield naturally leads to mass regulating dust attenuation. Infall of low-metallicity gas increases the SFR and lowers the metallicity, but leaves the dust column density mostly unchanged. We quantify this idea using the Kennicutt–Schmidt and fundamental metallicity relations, showing that galaxy mass is indeed the primary driver of dust attenuation.