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Physics and Astronomy Faculty Publications

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Articles 61 - 90 of 679

Full-Text Articles in Astrophysics and Astronomy

The Mosdef-Lris Survey: Detection Of Inflowing Gas Towards Three Star-Forming Galaxies At Z ∼ 2, Andrew Weldon, Naveen Reddy, Michael W. Topping, Alice E. Shapley, Xinnan Du, Sedona H. Price, Ryan L. Sanders, Alison L. Coil, Bahram Mobasher, Mariska Kriek, Brian Siana, Saeed Rezaee Jan 2023

The Mosdef-Lris Survey: Detection Of Inflowing Gas Towards Three Star-Forming Galaxies At Z ∼ 2, Andrew Weldon, Naveen Reddy, Michael W. Topping, Alice E. Shapley, Xinnan Du, Sedona H. Price, Ryan L. Sanders, Alison L. Coil, Bahram Mobasher, Mariska Kriek, Brian Siana, Saeed Rezaee

Physics and Astronomy Faculty Publications

We report on the discovery of cool gas inflows towards three star-forming galaxies at ∼ 2.30. Analysis of Keck Low-Resolution Imaging Spectrometer spectroscopy reveals redshifted low-ionization interstellar (LIS) metal absorption lines with centroid velocities of 60–130 km s−1. These inflows represent some of the most robust detections of inflowing gas into isolated, star-forming galaxies at high redshift. Our analysis suggests that the inflows are due to recycling metal-enriched gas from previous ejections. Comparisons between the galaxies with inflows and a larger parent sample of 131 objects indicate that galaxies with detected inflows may have higher specific star formation …

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The Impact Of Star-Formation-Rate Surface Density On The Electron Density And Ionization Parameter Of High-Redshift Galaxies, Naveen Reddy, Ryan L. Sanders, Alice E. Shapley, Michael W. Topping, Mariska Kriek, Alison L. Coil, Bahram Mobasher, Brian Siana, Saeed Rezaee Jan 2023

The Impact Of Star-Formation-Rate Surface Density On The Electron Density And Ionization Parameter Of High-Redshift Galaxies, Naveen Reddy, Ryan L. Sanders, Alice E. Shapley, Michael W. Topping, Mariska Kriek, Alison L. Coil, Bahram Mobasher, Brian Siana, Saeed Rezaee

Physics and Astronomy Faculty Publications

We use the large spectroscopic data set of the MOSFIRE Deep Evolution Field survey to investigate some of the key factors responsible for the elevated ionization parameters (U) inferred for high-redshift galaxies, focusing in particular on the role of star-formation-rate surface density (ΣSFR). Using a sample of 317 galaxies with spectroscopic redshifts z spec ≃ 1.9-3.7, we construct composite rest-frame optical spectra in bins of ΣSFR and infer electron densities, n e, using the ratio of the [O ii] λ λ3727, 3730 doublet. Our analysis suggests a significant (≃3σ) correlation between n e and ΣSFR …

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Beam Energy Dependence Of The Linear And Mode-Coupled Flow Harmonics In Au+Au Collisions, Star Collaboration Jan 2023

Beam Energy Dependence Of The Linear And Mode-Coupled Flow Harmonics In Au+Au Collisions, Star Collaboration

Physics and Astronomy Faculty Publications

The linear and mode-coupled contributions to higher-order anisotropic flow are presented for Au+Au collisions at √sNN = 27, 39, 54.4, and 200 GeV and compared to similar measurements for Pb+Pb collisions at the Large Hadron Collider (LHC). The coefficients and the flow harmonics’ correlations, which characterize the linear and mode-coupled response to the lower-order anisotropies, indicate a beam energy dependence consistent with an influence from the specific shear viscosity (η /s). In contrast, the dimensionless coefficients, mode-coupled response coefficients, and normalized symmetric cumulants are approximately beam-energy independent, consistent with a significant role from initial- state effects. These measurements could provide …

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Energy Dependence Of Intermittency For Charged Hadrons In Au+Au Collisions At Rhic, The Star Collaboration Jan 2023

Energy Dependence Of Intermittency For Charged Hadrons In Au+Au Collisions At Rhic, The Star Collaboration

Physics and Astronomy Faculty Publications

Density fluctuations near the QCD critical point can be probed via an intermittency analysis in relativistic heavy-ion collisions. We report the first measurement of intermittency in Au+Au collisions at √sNN = 7.7-200 GeV measured by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The scaled factorial moments of identified charged hadrons are analyzed at mid-rapidity and within the transverse momentum phase space. We observe a power-law behavior of scaled factorial moments in Au+Au collisions and a decrease in the extracted scaling exponent (ν) from peripheral to central collisions. The ν is consistent with a constant for different collisions …

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Global Polarization Of Λ And Λ¯ Hyperons In Au+Au Collisions At √S Nn = 19.6 And 27 Gev, Star Collaboration Jan 2023

Global Polarization Of Λ And Λ¯ Hyperons In Au+Au Collisions At √S Nn = 19.6 And 27 Gev, Star Collaboration

Physics and Astronomy Faculty Publications

In relativistic heavy-ion collisions, a global spin polarization, PH, of Λ and Λ¯ hyperons along the direction of the system angular momentum was discovered and measured across a broad range of collision energies and demonstrated a trend of increasing PH with decreasing √sNN. A splitting between Λ and Λ¯ polarization may be possible due to their different magnetic moments in a late-stage magnetic field sustained by the quark-gluon plasma which is formed in the collision. The results presented in this study find no significant splitting at the collision energies of √sNN=19.6 and 27 GeV in the BNL Relativistic Heavy Ion …

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Measurements Of Dielectron Production In Au + Au Collisions At √Snn = 27, 39, And 62.4 Gev From The Star Experiment, Star Collaboration Jan 2023

Measurements Of Dielectron Production In Au + Au Collisions At √Snn = 27, 39, And 62.4 Gev From The Star Experiment, Star Collaboration

Physics and Astronomy Faculty Publications

We report systematic measurements of dielectron (e+e−) invariant-mass Mee spectra at midrapidity in Au + Au collisions at √s NN = 27, 39, and 62.4 GeV taken with the STAR detector at the Relativistic Heavy Ion Collider. For all energies studied, a significant excess yield of dielectrons is observed in the low-mass region (0.40 < M ee < 0.75 MeV/c2 ) compared to hadronic cocktail simulations at freeze-out. Models that include an in-medium broadening of the ρ-meson spectral function consistently describe the observed excess. In addition, we report acceptance-corrected dielectron-excess spectra for Au + Au collisions at midrapidity (|yee| < 1) in the 0–80% centrality bin for each collision energy. The integrated excess yields for 0.4 < Mee < 0.75 GeV/c2 , normalized by the charged particle multiplicity at midrapidity, are compared with previously published measurements for Au + Au at √s NN = 19.6 and 200 GeV. Models that include an in-medium broadening of the ρ-meson spectral function consistently describe the observed excess. The normalized excess yields in the low-mass region show no significant collision energy dependence. The data, however, are consistent with model calculations that demonstrate a modest energy dependence.

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Measurements Of The Elliptic And Triangular Azimuthal Anisotropies In Central 3he + Au, D + Au And P + Au Collisions At √Snn P = 200 Gev, Star Collaboration Jan 2023

Measurements Of The Elliptic And Triangular Azimuthal Anisotropies In Central 3he + Au, D + Au And P + Au Collisions At √Snn P = 200 Gev, Star Collaboration

Physics and Astronomy Faculty Publications

The elliptic (v2) and triangular (v3) azimuthal anisotropy coefficients in central He3+Au, d+Au, and p+Au collisions at sNN=200 GeV are measured as a function of transverse momentum (pT) at midrapidity (|η|< 0.9), via the azimuthal angular correlation between two particles both at |η|< 0.9. While the v2(pT) values depend on the colliding systems, the v3(pT) values are system independent within the uncertainties, suggesting an influence on eccentricity from subnucleonic fluctuations in these small-sized systems. These results also provide stringent constraints for the hydrodynamic modeling of these systems.

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K∗0 Production In Au + Au Collisions At √Snn = 7.7, 11.5, 14.5, 19.6, 27, And 39 Gev From The Rhic Beam Energy Scan, Star Collaboration Jan 2023

K∗0 Production In Au + Au Collisions At √Snn = 7.7, 11.5, 14.5, 19.6, 27, And 39 Gev From The Rhic Beam Energy Scan, Star Collaboration

Physics and Astronomy Faculty Publications

We report the measurement of K∗0 meson at midrapidity (|y| < 1.0) in Au + Au collisions at √sNN = 7.7, 11.5, 14.5, 19.6, 27, and 39 GeV collected by the STAR experiment during the Relativistic Heavy Ion Collider (RHIC) beam energy scan program. The transverse momentum spectra, yield, and average transverse momentum of K∗0 are presented as functions of collision centrality and beam energy. The K∗0/K yield ratios are presented for different collision centrality intervals and beam energies. The K∗0/K ratio in heavy-ion collisions are observed to be smaller than that in small-system collisions (e + e and p + p). The K∗0/K ratio follows a similar centrality dependence to that observed in previous RHIC and Large Hadron Collider measurements. The data favor the scenario of the dominance of hadronic rescattering over regeneration for K∗0 production in the hadronic phase of the medium.

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Observation Of Directed Flow Of Hypernuclei 3/Λ H And 4/Λ H In √𝑠nn=3  Gev Au+Au Collisions At Rhic, Star Collaboration Jan 2023

Observation Of Directed Flow Of Hypernuclei 3/Λ H And 4/Λ H In √𝑠nn=3  Gev Au+Au Collisions At Rhic, Star Collaboration

Physics and Astronomy Faculty Publications

We report here the first observation of directed flow (v1) of the hypernuclei H/Λ 3 and H/Λ 4 in mid-central Au+Au collisions at √sNN=3 GeV at RHIC. These data are taken as part of the beam energy scan program carried out by the STAR experiment. From 165×106 events in 5%-40% centrality, about 8400 H/Λ 3 and 5200 H/Λ 4 candidates are reconstructed through two- and three-body decay channels. We observe that these hypernuclei exhibit significant directed flow. Comparing to that of light nuclei, it is found that the midrapidity v1 slopes of H/Λ 3 and H/Λ 4 follow baryon number …

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Pion, Kaon, And (Anti)Proton Production In U+U Collisions At √Snn = 193 Gev Measured With The Star Detector, Star Collaboration Jan 2023

Pion, Kaon, And (Anti)Proton Production In U+U Collisions At √Snn = 193 Gev Measured With The Star Detector, Star Collaboration

Physics and Astronomy Faculty Publications

We present the first measurements of transverse momentum spectra of π±, K±, p( ¯p) at midrapidity (|y| < 0.1) in U+U collisions at √s NN = 193 GeV with the STAR detector at the Relativistic Heavy Ion Collider (RHIC). The centrality dependence of particle yields, average transverse momenta, particle ratios and kinetic freeze-out parameters are discussed. The results are compared with the published results from Au+Au collisions at √s NN = 200 GeV in STAR. The results are also compared to those from A Multi-Phase Transport ( AMPT) model.

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Search For The Chiral Magnetic Effect In Au+Au Collisions At √Snn = 27 Gev With The Star Forward Event Plane Detectors, Star Collaboration Jan 2023

Search For The Chiral Magnetic Effect In Au+Au Collisions At √Snn = 27 Gev With The Star Forward Event Plane Detectors, Star Collaboration

Physics and Astronomy Faculty Publications

A decisive experimental test of the Chiral Magnetic Effect (CME) is considered one of the major scientific goals at the Relativistic Heavy-Ion Collider (RHIC) towards understanding the nontrivial topological fluctuations of the Quantum Chromodynamics vacuum. In heavy-ion collisions, the CME is expected to result in a charge separation phenomenon across the reaction plane, whose strength could be strongly energy dependent. The previous CME searches have been focused on top RHIC energy collisions. In this Letter, we present a low energy search for the CME in Au+Au collisions at √sNN = 27 GeV. We measure elliptic flow scaled charge-dependent correlators relative …

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Search For The Chiral Magnetic Wave Using Anisotropic Flow Of Identified Particles At Energies Available At The Bnl Relativistic Heavy Ion Collider, Star Collaboration Jan 2023

Search For The Chiral Magnetic Wave Using Anisotropic Flow Of Identified Particles At Energies Available At The Bnl Relativistic Heavy Ion Collider, Star Collaboration

Physics and Astronomy Faculty Publications

The chiral magnetic wave (CMW) has been theorized to propagate in the deconfined nuclear medium formed in high-energy heavy-ion collisions and to cause a difference in elliptic flow (𝑣2) between negatively and positively charged hadrons. Experimental data consistent with the CMW have been reported by the STAR Collaboration at the Relativistic Heavy Ion Collider (RHIC), based on the charge asymmetry dependence of the pion 𝑣2 from Au +Au collisions at √𝑠𝑁⁢𝑁=27 to 200 GeV. In this comprehensive study, we present the STAR measurements of elliptic flow and triangular flow of charged pions, along with the 𝑣2 of charged kaons and …

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Ecce Sensitivity Studies For Single Hadron Transverse Single Spin Asymmetry Measurements, R. Seidl, A. Vladimirov, D. Pitonyak, A. Prokudin Jan 2023

Ecce Sensitivity Studies For Single Hadron Transverse Single Spin Asymmetry Measurements, R. Seidl, A. Vladimirov, D. Pitonyak, A. Prokudin

Physics and Astronomy Faculty Publications

We performed feasibility studies for various single transverse spin measurements that are related to the Sivers effect, transversity and the tensor charge, and the Collins fragmentation function. The processes studied include semi-inclusive deep inelastic scattering (SIDIS) where single hadrons (pions and kaons) were detected in addition to the scattered DIS lepton. The data were obtained in pythia6 and geant4 simulated e+p collisions at 18 GeV on 275 GeV, 18 on 100, 10 on 100, and 5 on 41 that use the ECCE detector configuration. Typical DIS kinematics were selected, most notably 𝑄2 > 1 GeV2, and cover the 𝑥 range from …

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Exclusive J/𝜓 Detection And Physics With Ecce, X. Li Jan 2023

Exclusive J/𝜓 Detection And Physics With Ecce, X. Li

Physics and Astronomy Faculty Publications

The EIC Comprehensive Chromodynamics Experiment (ECCE) detector has been recommended as a reference design for the proposed Electron-Ion Collider (EIC) program. This paper presents simulation studies of exclusive J/𝜓 detection and selected physics impact results in EIC using the projected ECCE detector concept. Exclusive quarkonium photoproduction is one of the most popular processes in EIC, which has a large cross section and a simple final state. Due to the gluonic nature of the exchange Pomeron, this process can be related to the gluon distributions in the nucleus. Preliminary results estimate the excellent statistics benefited from the large cross section of …

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Beam Energy Dependence Of Fifth- And Sixth-Order Net-Proton Number Fluctuations In Au + Au Collisions At Rhic, Star Collaboration Jan 2023

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 …

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Accurate Oxygen Abundance Of Interstellar Gas In Mrk 71 From Optical And Infrared Spectra, Yuguang Chen, Tucker Jones, Ryan Sanders, Dario Fadda, Jessica Sutter, Robert Minchin, Erin Huntzinger, Peter Senchyna, Daniel Stark, Justin Spilker, Benjamin J. Weiner, Guido Roberts-Borsani Jan 2023

Accurate Oxygen Abundance Of Interstellar Gas In Mrk 71 From Optical And Infrared Spectra, Yuguang Chen, Tucker Jones, Ryan Sanders, Dario Fadda, Jessica Sutter, Robert Minchin, Erin Huntzinger, Peter Senchyna, Daniel Stark, Justin Spilker, Benjamin J. Weiner, Guido Roberts-Borsani

Physics and Astronomy Faculty Publications

The heavy element content (“metallicity”) of the Universe is a record of the total star formation history. Gas-phase metallicity in galaxies, as well as its evolution with time, is of particular interest as a tracer of accretion and outflow processes. However, metallicities from the widely-used electron temperature (Te) method are typically ∼ 2× lower than the values based on the recombination line method. This “abundance discrepancy factor” (ADF) is well known and is commonly ascribed to bias due to temperature fluctuations. We present a measurement of oxygen abundance in the nearby (3.4 Mpc) system, Mrk 71, using a combination of …

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Excitation And Ionization Properties Of Star-Forming Galaxies At Z = 2.0-9.3 With Jwst/Nirspec, Ryan L. Sanders, Alice E. Shapley, Michael W. Topping, Naveen Reddy, Gabriel B. Brammer Jan 2023

Excitation And Ionization Properties Of Star-Forming Galaxies At Z = 2.0-9.3 With Jwst/Nirspec, Ryan L. Sanders, Alice E. Shapley, Michael W. Topping, Naveen Reddy, Gabriel B. Brammer

Physics and Astronomy Faculty Publications

We utilize medium-resolution JWST/NIRSpec observations of 164 galaxies at z = 2.0-9.3 from the Cosmic Evolution Early Release Science (CEERS) survey to investigate the evolution of the excitation and ionization properties of galaxies at high redshifts. Our results represent the first statistical constraints on the evolution of the [O III]/Hβ versus [N II]/Hα, [S II]/Hα, and [O I]/Hα “BPT” diagrams at z > 2.7, and the first analysis of the O32 versus R23 diagram at z > 4 with a large sample. We divide the sample into five redshift bins containing 30-40 galaxies each. The subsamples at z ∼ 2.3, …

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Boost The Lead Conversion Efficiency For The Synthesis Of Colloidal 2d Pbs Nanosheets, Tharaka Mds Weeraddana, Adam Roach, Shashini M. Premathilaka, Yiteng Tang, Jordan Fox, Liangfeng Sun Nov 2022

Boost The Lead Conversion Efficiency For The Synthesis Of Colloidal 2d Pbs Nanosheets, Tharaka Mds Weeraddana, Adam Roach, Shashini M. Premathilaka, Yiteng Tang, Jordan Fox, Liangfeng Sun

Physics and Astronomy Faculty Publications

In the synthesis of colloidal PbS nanosheets, the supernatant of the reaction solution is reused to boost the lead conversion efficiency. It doubles the conversion efficiency of the lead precursors to the PbS nanosheets. The nanosheets synthesized by reusing the supernatant have similar morphology, nearly identical thickness, and optical properties as the original ones, confirmed by transmission electron microscopy, X-ray diffraction, and photoluminescence spectroscopy. This method reduces the toxic Pb-containing waste during the synthesis, a step toward the green and scalable synthesis of colloidal 2D PbS nanosheets.

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Neutron Stars With Baryon Number Violation, Probing Dark Sectors, Jeffrey M. Berryman, Susan Gardner, Mohammadreza Zakeri Mar 2022

Neutron Stars With Baryon Number Violation, Probing Dark Sectors, Jeffrey M. Berryman, Susan Gardner, Mohammadreza Zakeri

Physics and Astronomy Faculty Publications

The neutron lifetime anomaly has been used to motivate the introduction of new physics with hidden-sector particles coupled to baryon number, and on which neutron stars provide powerful constraints. Although the neutron lifetime anomaly may eventually prove to be of mundane origin, we use it as motivation for a broader review of the ways that baryon number violation, be it real or apparent, and dark sectors can intertwine and how neutron star observables, both present and future, can constrain them.

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Path Integral Complexity And Kasner Singularities, Pawel Caputa, Diptarka Das, Sumit R. Das Jan 2022

Path Integral Complexity And Kasner Singularities, Pawel Caputa, Diptarka Das, Sumit R. Das

Physics and Astronomy Faculty Publications

We explore properties of path integral complexity in field theories on time dependent backgrounds using its dual description in terms of Hartle-Hawking wavefunctions. In particular, we consider boundary theories with time dependent couplings which are dual to Kasner-AdS metrics in the bulk with a time dependent dilaton. We show that holographic path integral complexity decreases as we approach the singularity, consistent with earlier results from holographic complexity conjectures. Furthermore, we find examples where the complexity becomes universal i.e., independent of the Kasner exponents, but the properties of the path integral tensor networks depend sensitively on this data.

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Athena Detector Proposal — A Totally Hermetic Electron Nucleus Apparatus Proposed For Ip6 At The Electron-Ion Collider, The Athena Collaboration Jan 2022

Athena Detector Proposal — A Totally Hermetic Electron Nucleus Apparatus Proposed For Ip6 At The Electron-Ion Collider, The Athena Collaboration

Physics and Astronomy Faculty Publications

ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity. This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&D required to meet those challenges.

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Collision-System And Beam-Energy Dependence Of Anisotropic Flow Fluctuations, Star Collaboration Jan 2022

Collision-System And Beam-Energy Dependence Of Anisotropic Flow Fluctuations, Star Collaboration

Physics and Astronomy Faculty Publications

Elliptic flow measurements from two-, four-, and six-particle correlations are used to investigate flow fluctuations in collisions of U+U at √𝑠NN=193  GeV, Cu+Au at √𝑠NN=200  GeV and Au+Au spanning the range √𝑠NN=11.5–200  GeV. The measurements show a strong dependence of the flow fluctuations on collision centrality, a modest dependence on system size, and very little if any, dependence on particle species and beam energy. The results, when compared to similar LHC measurements, viscous hydrodynamic calculations, and trento model eccentricities, indicate that initial-state-driven fluctuations predominate the flow fluctuations generated in the collisions studied.

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Differential Measurements Of Jet Substructure And Partonic Energy Loss In Au + Au Collisions At √𝑠𝑁⁢𝑁=200 Gev, Star Collaboration Jan 2022

Differential Measurements Of Jet Substructure And Partonic Energy Loss In Au + Au Collisions At √𝑠𝑁⁢𝑁=200 Gev, Star Collaboration

Physics and Astronomy Faculty Publications

The STAR collaboration presents jet substructure measurements related to both the momentum fraction and the opening angle within jets in 𝑝+𝑝 and Au+Au collisions at √𝑠𝑁⁢𝑁 =200GeV. The substructure observables include SoftDrop groomed momentum fraction (𝑧𝑔), groomed jet radius (𝑅𝑔), and subjet momentum fraction (𝑧SJ) and opening angle (𝜃SJ). The latter observable is introduced for the first time. Fully corrected subjet measurements are presented for 𝑝+𝑝 collisions and are compared to leading-order Monte Carlo models. The subjet 𝜃SJ distributions reflect the jets leading opening angle and are utilized as a proxy for the resolution scale of the medium in Au+Au …

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Disappearance Of Partonic Collectivity In √Snn = 3 Gev Au+Au Collisions At Rhic, Star Collaboration Jan 2022

Disappearance Of Partonic Collectivity In √Snn = 3 Gev Au+Au Collisions At Rhic, Star Collaboration

Physics and Astronomy Faculty Publications

We report on the measurements of directed flow v1 and elliptic flow v2 for hadrons (π±, K ±, K 0 S , p, φ, Λ and Ξ−) from Au+Au collisions at √sNN = 3 GeV and v2 for (π±, K ±, p and p) at 27 and 54.4 GeV with the STAR experiment. While at the two higher energy midcentral collisions the number-of-constituent-quark (NCQ) scaling holds, at 3 GeV the v2 at midrapidity is negative for all hadrons and the NCQ scaling is absent. In addition, the v1 slopes at midrapidity for almost all observed hadrons are found to be …

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Centrality And Transverse-Momentum Dependence Of Higher-Order Flow Harmonics Of Identified Hadrons In Au+Au Collisions At √𝑠𝑁⁢𝑁=200 Gev, Star Collaboration Jan 2022

Centrality And Transverse-Momentum Dependence Of Higher-Order Flow Harmonics Of Identified Hadrons In Au+Au Collisions At √𝑠𝑁⁢𝑁=200 Gev, Star Collaboration

Physics and Astronomy Faculty Publications

We present high-precision measurements of elliptic, triangular, and quadrangular flow 𝑣2, 𝑣3, and 𝑣4, respectively, at midrapidity for identified hadrons 𝜋, 𝑝, 𝐾, 𝜑, 𝐾𝑠, Λ as a function of centrality and transverse momentum in Au+Au collisions at the center-of-mass energy √𝑠𝑁⁢𝑁=200 GeV. We observe similar 𝑣𝑛 trends between light and strange mesons which indicates that the heavier strange quarks flow as strongly as the lighter up and down quarks. The number-of-constituent-quark scaling for 𝑣2, 𝑣3, and 𝑣4 is found to hold within statistical uncertainty for 0–10%, 10–40%, and 40–80% collision centrality intervals. The results are compared to several viscous …

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Azimuthal Transverse Single-Spin Asymmetries Of Inclusive Jets And Identified Hadrons Within Jets From Polarized 𝑝⁢𝑝 Collisions At √𝑠 =200  Gev, Star Collaboration Jan 2022

Azimuthal Transverse Single-Spin Asymmetries Of Inclusive Jets And Identified Hadrons Within Jets From Polarized 𝑝⁢𝑝 Collisions At √𝑠 =200  Gev, Star Collaboration

Physics and Astronomy Faculty Publications

The STAR Collaboration reports measurements of the transverse single-spin asymmetries, 𝐴𝑁, for inclusive jets and identified “hadrons within jets” production at midrapidity from transversely polarized 𝑝⁢𝑝 collisions at √𝑠 =200  GeV, based on data recorded in 2012 and 2015. The inclusive jet asymmetry measurements include 𝐴𝑁 for inclusive jets and 𝐴𝑁 for jets containing a charged pion carrying a momentum fraction 𝑧 >0.3 of the jet momentum. The identified hadron within jet asymmetry measurements include the Collins effect for charged pions, kaons, and protons, and the Collins-like effect for charged pions. The measured asymmetries are determined for several distinct kinematic …

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Evidence For Nonlinear Gluon Effects In Qcd And Their Mass Number Dependence At Star, Star Collaboration Jan 2022

Evidence For Nonlinear Gluon Effects In Qcd And Their Mass Number Dependence At Star, Star Collaboration

Physics and Astronomy Faculty Publications

The STAR Collaboration reports measurements of back-to-back azimuthal correlations of di-𝜋0s produced at forward pseudorapidities (2.6 < 𝜂 < 4.0) in 𝑝 +𝑝, 𝑝+Al, and 𝑝+Au collisions at a center-of-mass energy of 200 GeV. We observe a clear suppression of the correlated yields of back-to-back 𝜋0 pairs in 𝑝+Al and 𝑝+Au collisions compared to the 𝑝 +𝑝 data. The observed suppression of back-to-back pairs as a function of transverse momentum suggests nonlinear gluon dynamics arising at high parton densities. The larger suppression found in 𝑝+Au relative to 𝑝+Al collisions exhibits a dependence of the saturation scale 𝑄2/𝑠 on the mass number 𝐴. A linear scaling of the suppression with 𝐴1/3 is observed with a slope of −0.09 ±0.01.

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Evidence For Electron Energization Accompanying Spontaneous Formation Of Ion Acceleration Regions In Expanding Plasmas, Evan M. Aguirre, Rikard Bodin, Neng Yin, Timothy N. Good, Earl E. Scime Dec 2020

Evidence For Electron Energization Accompanying Spontaneous Formation Of Ion Acceleration Regions In Expanding Plasmas, Evan M. Aguirre, Rikard Bodin, Neng Yin, Timothy N. Good, Earl E. Scime

Physics and Astronomy Faculty Publications

We report experiments conducted in an expanding argon plasma generated in the inductive mode of a helicon source in the Hot hELIcon eXperiment–Large Experiment on Instabilities and Anisotropies facility. As the neutral gas pressure increases, the supersonic ion acceleration weakens. Increasing neutral pressure also alters the radial profile of electron temperature, density, and plasma potential upstream of the plasma expansion region. Langmuir probe measurements of the electron energy probability function (EEPF) show that heating of electrons at the plasma edge by RF fields diminishes with increasing gas pressure, yielding a plasma with a centrally peaked electron temperature, and flat potential …

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Space Telescope And Optical Reverberation Mapping Project. Xi. Disk-Wind Characteristics And Contributions To The Very Broad Emission Lines Of Ngc 5548, Maryam Dehghanian, Gary J. Ferland, G. A. Kriss, B. M. Peterson, K. T. Korista, M. R. Goad, Marios Chatzikos, Francisco Guzmán, G. De Rosa, M. Mehdipour, J. Kaastra, S. Mathur, M. Vestergaard, D. Proga, T. Waters, M. C. Bentz, S. Bisogni, W. N. Brandt, E. Dalla Bontà, M. M. Fausnaugh, J. M. Gelbord, Keith Horne, I. M. Mchardy, R. W. Pogge, D. A. Starkey Aug 2020

Space Telescope And Optical Reverberation Mapping Project. Xi. Disk-Wind Characteristics And Contributions To The Very Broad Emission Lines Of Ngc 5548, Maryam Dehghanian, Gary J. Ferland, G. A. Kriss, B. M. Peterson, K. T. Korista, M. R. Goad, Marios Chatzikos, Francisco Guzmán, G. De Rosa, M. Mehdipour, J. Kaastra, S. Mathur, M. Vestergaard, D. Proga, T. Waters, M. C. Bentz, S. Bisogni, W. N. Brandt, E. Dalla Bontà, M. M. Fausnaugh, J. M. Gelbord, Keith Horne, I. M. Mchardy, R. W. Pogge, D. A. Starkey

Physics and Astronomy Faculty Publications

In 2014 the NGC 5548 Space Telescope and Optical Reverberation Mapping campaign discovered a two-month anomaly when variations in the absorption and emission lines decorrelated from continuum variations. During this time the soft X-ray part of the intrinsic spectrum had been strongly absorbed by a line-of-sight (LOS) obscurer, which was interpreted as the upper part of a disk wind. Our first paper showed that changes in the LOS obscurer produces the decorrelation between the absorption lines and the continuum. A second study showed that the base of the wind shields the broad emission-line region (BLR), leading to the emission-line decorrelation. …

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Vla Imaging Of H I-Bearing Ultra-Diffuse Galaxies From The Alfalfa Survey, Lexi Gault, Lukas Leisman, Elizabeth A.K. Adams, Pavel E. Mancera Piña, Kameron Reiter, Nicholas Smith, Michael Battipaglia, John M. Cannon, Filippo Fraternali, Martha P. Haynes, Elizabeth Mcallan, Hannah J. Pagel, Katherine L. Rhode, John J. Salzer, Quinton Singer Jan 2020

Vla Imaging Of H I-Bearing Ultra-Diffuse Galaxies From The Alfalfa Survey, Lexi Gault, Lukas Leisman, Elizabeth A.K. Adams, Pavel E. Mancera Piña, Kameron Reiter, Nicholas Smith, Michael Battipaglia, John M. Cannon, Filippo Fraternali, Martha P. Haynes, Elizabeth Mcallan, Hannah J. Pagel, Katherine L. Rhode, John J. Salzer, Quinton Singer

Physics and Astronomy Faculty Publications

Ultra-diffuse galaxies have generated significant interest due to their large optical extents and low optical surface brightnesses, which challenge galaxy formation models. Here we present resolved synthesis observations of 12 H i-bearing ultra-diffuse galaxies (HUDs) from the Karl G. Jansky Very Large Array (VLA), as well as deep optical imaging from the WIYN 3.5-meter telescope at Kitt Peak National Observatory. We present the data processing and images, including total intensity H i maps and H i velocity fields. The HUDs show ordered gas distributions and evidence of rotation, important prerequisites for the detailed kinematic models in Mancera Pi˜na et al. …

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