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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Giant Outer Transiting Exoplanet Mass (GOT ‘EM) Survey. II. Discovery of a Failed Hot Jupiter on a 2.7 Yr, Highly Eccentric Orbit

Radial velocity (RV) surveys have discovered giant exoplanets on au-scale orbits with a broad distribution of eccentricities. Those with the most eccentric orbits are valuable laboratories for testing theories of high-eccentricity migration. However, few such exoplanets transit their host stars, thus removing the ability to apply constraints on formation from their bulk internal compositions. We report the discovery of Kepler-1704 b, a transiting 4.15 M {sub J} giant planet on a 988.88 day orbit with an extreme eccentricity of 0.921{sub -0.015}{sup +0.010}. Our decade-long RV baseline from the Keck I telescope allows us to measure the orbit and bulk heavy-element composition of Kepler-1704 b and place limits on the existence of undiscovered companions. A failed hot Jupiter, Kepler-1704 b was likely excited to high eccentricity by scattering events that possibly began during its gas accretion phase. Its final periastron distance was too large to allow for tidal circularization, so now it orbits its host from distances spanning 0.16–3.9 au. The maximum difference in planetary equilibrium temperature resulting from this elongated orbit is over 700 K. A simulation of the thermal phase curve of Kepler-1704 b during periastron passage demonstrates that it is a remarkable target for atmospheric characterization from the James Webb Space Telescope, which could potentially also measure the planet’s rotational period as the hot spot from periastron rotates in and out of view. Continued characterization of the Kepler-1704 system promises to refine theories explaining the formation of hot Jupiters and cool giant planets like those in the solar system.

47 OTHER INSTRUMENTATION↗
DOE OSTI2025

Hyperon global polarization in isobar Ru+Ru and Zr+Zr collisions at $\sqrt{s_{NN}}$ = 200Ge V

The polarization of Λ, $\overline{Λ}$, $Ξ$ – , and $\overline{Ξ}$ + hyperons along the angular momentum of the system has been measured in isobar collisions of Ru+Ru and Zr+Zr at $\sqrt{s_{NN}}$ = 200 GeV with the STAR detector at RHIC. The polarization dependence on collision centrality exhibits an increasing trend in more peripheral collisions. Λ and $\overline{Λ}$ polarization dependence on the transverse momentum and pseudorapidity have been investigated, but no significant dependence was observed. The polarizations of Λ and $\overline{Λ}$ are found to be consistent with each other, indicating little contribution of the spin-magnetic coupling to the measured polarization. Comparison to previously measured polarization in Au+Au collisions show no obvious system size dependence. The results are qualitatively consistent with hydrodynamic calculations including contributions from shear-induced polarization and thermal vorticity. For the first time in heavy-ion collisions, the dependence of the global polarization on the hyperon’s emission azimuthal angle relative to the second-order event plane has been measured, indicating stronger polarization for the in-plane emitted hyperons at the level of 2.4 σ significance in 20–50 % centrality. The $Ξ$ hyperon polarization measurements via polarization transfer analysis yield finite positive values with 2.9 σ significance in 20–50 % centrality, slightly larger compared to the inclusive Λ polarization.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2026

Identified charged hadron production in Au+Au collisions at $\sqrt{s_{NN}}$ = 54.4 GeV with the STAR detector

Here, we present results on the production of 𝜋±, 𝐾±, 𝑝, and $\bar{𝑝}$ in Au+Au collisions at $\sqrt{𝑠_{N⁢N}}$ = 54.4~GeV using the STAR detector at RHIC, at mid-rapidity (|𝑦|< 0.1). Invariant yields of these particles as a function of transverse momentum are shown. We determine bulk properties such as integrated particle yields (𝑑 ⁢𝑁 /𝑑 ⁢𝑦 ), mean transverse momentum (⟨𝑝 𝑇 ⟩), particle ratios, which provide insight into the particle production mechanisms. Additionally, the kinetic freeze-out parameters (𝑇 kin and ⟨𝛽 𝑇 ⟩), which provide information about the dynamics of the system at the time of freeze-out, are obtained. The Bjorken energy density (𝜖 𝐵⁢𝐽 ), which gives an estimate of the energy density in the central rapidity region of the collision zone at the formation time 𝜏, is calculated and presented as a function of multiplicity for various energies. The results are compared with those from the models such as A Multi-Phase Transport (AMPT) and Heavy Ion Jet INteraction Generator (HIJING) for further insights.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2021

First Detection of Orbital Motion for HD 106906 b: A Wide-separation Exoplanet on a Planet Nine–like Orbit

HD 106906 is a 15 Myr old short-period (49 days) spectroscopic binary that hosts a wide-separation (737 au) planetary-mass (∼11 M{sub Jup}) common proper motion companion, HD 106906 b. Additionally, a circumbinary debris disk is resolved at optical and near-infrared wavelengths that exhibits a significant asymmetry at wide separations that may be driven by gravitational perturbations from the planet. In this study we present the first detection of orbital motion of HD 106906 b using Hubble Space Telescope images spanning a 14 yr period. We achieve high astrometric precision by cross-registering the locations of background stars with the Gaia astrometric catalog, providing the subpixel location of HD 106906 that is either saturated or obscured by coronagraphic optical elements. We measure a statistically significant 31.8 ± 7.0 mas eastward motion of the planet between the two most constraining measurements taken in 2004 and 2017. This motion enables a measurement of the inclination between the orbit of the planet and the inner debris disk of either 36{sub −14}{sup +27} deg or 44{sub −14}{sup +27} deg, depending on the true orientation of the orbit of the planet. There is a strong negative correlation between periastron and mutual inclination; orbits with smaller periastra are more misaligned with the disk plane. With a periastron of 510{sub −320}{sup +480} au, HD 106906 b is likely detached from the planetary region within 100 au radius, showing that a Planet Nine–like architecture can be established very early in the evolution of a planetary system.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

OGLE-2017-BLG-1434Lb: Confirmation of a Cold Super-Earth Using Keck Adaptive Optics

The microlensing event OGLE-2017-BLG-1434 features a cold super-Earth planet that is 1 of 11 microlensing planets with a planet–host-star mass ratio of q < 1 × 10{sup -4}. We provide an additional mass–distance constraint on the lens host using near-infrared adaptive optics photometry from Keck/NIRC2. We are able to determine a flux excess of K {sub L} = 16.96 ± 0.11, which most likely comes entirely from the lens star. Combining this with constraints from the large Einstein ring radius, θ {sub E} = 1.40 ± 0.09 mas, and OGLE parallax we confirm this event as a super-Earth with a mass of m {sub p} = 4.43 ± 0.25M {sub ⊕}. This system lies at a distance of D {sub L} = 0.86 ± 0.05 kpc from Earth and the lens star has a mass of M {sub L} = 0.234 ± 0.012M {sub ⊙}. We confirm that with a star–planet mass ratio of q = 0.57 × 10{sup -4}, OGLE-2017-BLG-1434 lies near the inflexion point of the planet–host mass-ratio power law.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2020

Exoplanets in the Antarctic Sky. IV. Dual-band Photometry of Variables Found by the CSTAR-II Commissioning Survey at the North Sky

From the experiences learned in three decades of exoplanet search, wide-field transit surveys have proven to be one of the most effective ways to detect exoplanets. Wide field of view, however, suffers from high false-positive rates caused by blended eclipsing binaries. The chromaticity in eclipse depth is an effective feature to distinguish low-depth eclipsing binaries from transiting exoplanets, making multiple-band photometry follow-up advantageous before a target is passed onto more expensive spectroscopic follow-up. Moreover, a multiple-band photometric survey is itself a powerful method to find and vet planetary candidates and narrow down the candidate list of high-priority targets. In this work, we report the first results of a dual-band (Sloan-g and -i) wide-field photometry survey—the Chinese Small Telescope ARray II (CSTAR-II), an updated version of the original CSTAR. As a key component of the Chinese Exoplanet Searching Program from Antarctica, CSTAR-II has been tested thoroughly at a remote arctic site near Mohe during the winter of 2014. In total, 13,531 light curves with the best overall photometric precision of ∼3 mmag were extracted from 7721 stars in the Sloan-g and -i bands. Using a robust method, we have detected 63 variables, of which 48 are newly discovered. The dual-band photometric results as well as the stellar properties of the detected sources are provided in this work.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2024

Three Quenched, Faint Dwarf Galaxies in the Direction of NGC 300: New Probes of Reionization and Internal Feedback

We report the discovery of three faint and ultra-faint dwarf galaxies -- Sculptor A, Sculptor B and Sculptor C -- in the direction of NGC 300 (D=2.0 Mpc), a Large Magellanic Cloud-mass galaxy. Deep ground-based imaging with Gemini/GMOS resolves all three dwarf galaxies into stars, each displaying a red giant branch indicative of an old, metal-poor stellar population. No young stars or HI gas are apparent, and the lack of a GALEX UV detection suggests that all three systems are quenched. Sculptor C (D=2.04$^{+0.10}_{-0.13}$ Mpc; $M_V=-9.1\pm 0.1$ mag or $L_V=(3.7^{+0.4}_{-0.3})\times 10^5L_{\odot})$ is consistent with being a satellite of NGC 300. Sculptor A (D=1.35$^{+0.22}_{-0.08}$ Mpc; $M_V=-6.9\pm 0.3$ mag or $L_V=(5^{+1}_{-1})\times 10^4 L_{\odot})$ is likely in the foreground of NGC 300 and at the extreme edge of the Local Group, analogous to the recently discovered ultra-faint Tucana B in terms of its physical properties and environment. Sculptor B (D=2.48$^{+0.21}_{-0.24}$ Mpc; $M_V=-8.1\pm 0.3$ mag or $L_V=(1.5^{+0.5}_{-0.4})\times 10^5L_{\odot})$ is likely in the background, but future distance measurements are necessary to solidify this statement. It is also of interest due to its quiescent state and low stellar mass. Both Sculptor A and B are $\gtrsim 2-4 r_{vir}$ from NGC 300 itself. The discovery of three dwarf galaxies in isolated or low-density environments offers an opportunity to study the varying effects of ram pressure stripping, reionization and internal feedback in influencing the star formation history of the faintest stellar systems.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2026

Measurement of the longitudinal flow-plane decorrelation using multiplane cumulants in $\sqrt{s_{NN}}$ = 200 GeV Au+Au, Ru+Ru, and Zr+Zr collisions

Measurements of the variation of anisotropic flow-plane angles (𝛹 𝑛 ) with rapidity, commonly known as the flow-plane decorrelation, provide important insights into the initial conditions of the matter produced in heavy-ion collisions. Here, in this paper, using data collected by the STAR experiment, we report the first measurement of the four-plane correlator observable 𝑇 𝑛 ⁡{𝑏⁢𝑎;𝑑⁢𝑐}=⟨⟨sin⁡[𝑛⁢(𝛹$^𝑏_𝑛$ − 𝛹$^𝑎_𝑛$)]⁢sin⁡[𝑛⁢(𝛹$^𝑑_𝑛$ − 𝛹$^𝑐_𝑛$)]⟩⟩, where superscripts 𝑎, 𝑏, 𝑐, and 𝑑 denote sequential pseudorapidity (𝜂) regions with 𝑎 corresponding to the most backward region, 𝑏 and 𝑐 close to mid-rapidity with 𝜂 𝑏 < 0 and 𝜂 𝑐 > 0, and 𝑑 being the most forward. The measurement is performed for the elliptic and triangular flow (i.e.~𝑛 = 2 and 3) in Au+Au and isobar (Ru+Ru, Zr+Zr) collisions at $\sqrt{s_{NN}}$=200~GeV. The goal of calculating the correlation of the flow-plane angle variations from backward to mid-central, and from mid-central to forward regions, is to probe the systematic variation of flow angle over a wide 𝜂 range. In mid-central collisions (10−30% centrality), we find 𝑇 2 ⁡{𝑏⁢𝑎;𝑑⁢𝑐} =−0.004 ±0.001⁢(s⁢t⁢a⁢t) ±0.002⁢(s⁢y⁢s⁢t) independent of the collision system. Such a small value of 𝑇 2 favors a random-walk'' variation of the flow-plane angles, where the rapidity correlation length is smaller than the entire region under study. These measurements provide new information on the decorrelation patterns in the system and offer a quantitative estimate of possible systematic variations in anisotropic flow angles such astwist’’ between forward and backward regions. This opens new opportunities for understanding the three-dimensional structure and the time evolution of the quark-gluon plasma created in heavy-ion collisions.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Temperature measurement of Quark-Gluon plasma at different stages

In a Quark-Gluon Plasma (QGP), the fundamental building blocks of matter, quarks and gluons, are under extreme conditions of temperature and density. A QGP could exist in the early stages of the Universe, and in various objects and events in the cosmos. The thermodynamic and hydrodynamic properties of the QGP are described by Quantum Chromodynamics (QCD) and can be studied in heavy-ion collisions. Despite being a key thermodynamic parameter, the QGP temperature is still poorly known. Thermal lepton pairs (e + e − and μ + μ − ) are ideal penetrating probes of the true temperature of the emitting source, since their invariant-mass spectra suffer neither from strong final-state interactions nor from blue-shift effects due to rapid expansion. Here we measure the QGP temperature using thermal e+e− production at the Relativistic Heavy Ion Collider (RHIC). The average temperature from the low-mass region (in-medium ρ 0 vector-meson dominant) is (2.01 ± 0.23) × 10 12 K, consistent with the chemical freeze-out temperature from statistical models and the phase transition temperature from Lattice QCD. The average temperature from the intermediate mass region (above the ρ0 mass, QGP dominant) is significantly higher at (3.25 ± 0.60) × 10 12 K. This work provides essential experimental thermodynamic measurements to map out the QCD phase diagram and understand the properties of matter under extreme conditions.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

Insights from binary pulsars and laboratories into baryon number violation: Implications for GeV dark matter

Rare processes in laboratory and within astrophysical environments can be highly sensitive probes of baryon-number-violating interactions at the TeV scale. We demonstrate the power of neutron stars to constrain baryon-number violation by considering a minimal extension of the standard model involving a TeV-mass scalar mediator and a GeV scale Majorana fermion ψ . We find that a Δ B = 2 mass-loss process in binary pulsar systems via n → γ ψ and the subsequent scattering ψ n → π − K + places stringent constraints on the model parameter space. These limits will become much stronger, due to the possibility of Λ → γ ψ decays at the tree level, if the neutron star equation of state is hyperonic. We compare these constraints with ongoing and future collider experiments, n − n ¯ oscillations, and dinucleon decay searches at future large-scale neutrino experiments, finding that the binary pulsars bounds on couplings are significantly tighter for specific flavor combinations. Published by the American Physical Society 2024

baryons↗
DOE OSTI2023

Barium stars as tracers of s -process nucleosynthesis in AGB stars: II. Using machine learning techniques on 169 stars

Barium (Ba) stars are characterised by an abundance of heavy elements made by the slow neutron capture process (s-process). This peculiar observed signature is due to the mass transfer from a stellar companion, bound in a binary stellar system, to the Ba star observed today. The signature is created when the stellar companion is an asymptotic giant branch (AGB) star. We aim to analyse the abundance pattern of 169 Ba stars using machine learning techniques and the AGB final surface abundances predicted by the FRUITY and Monash stellar models. We developed machine learning algorithms that use the abundance pattern of Ba stars as input to classify the initial mass and metallicity of each Ba star’s companion star using stellar model predictions. We used two algorithms. The first exploits neural networks to recognise patterns, and the second is a nearest-neighbour algorithm that focuses on finding the AGB model that predicts the final surface abundances closest to the observed Ba star values. In the second algorithm, we included the error bars and observational uncertainties in order to find the best-fit model. The classification process was based on the abundances of Fe, Rb, Sr, Zr, Ru, Nd, Ce, Sm, and Eu. We selected these elements by systematically removing s-process elements from our AGB model abundance distributions and identifying the elements whose removal had the biggest positive effect on the classification. We excluded Nb, Y, Mo, and La. Our final classification combined the output of both algorithms to identify an initial mass and metallicity range for each Ba star companion. With our analysis tools, we identified the main properties for 166 of the 169 Ba stars in the stellar sample. The classifications based on both stellar sets of AGB final abundances show similar distributions, with an average initial mass of M = 2.23 M ⊙ and 2.34 M ⊙ and an average [Fe/H] = –0.21 and –0.11, respectively. We investigated why the removal of Nb, Y, Mo, and La improves our classification and identified 43 stars for which the exclusion had the biggest effect. We found that these stars have statistically significant and different abundances for these elements compared to the other Ba stars in our sample. We discuss the possible reasons for these differences in the abundance patterns.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Higher order cumulants of net baryon-number distributions at non-zero μ

Using recent results on higher order cumulants of conserved charge fluctuations from lattice QCD, we construct mean, variance, skewness, kurtosis, hyper-skewness and hyper-kurtosis of net-baryon number distributions for small baryon chemical potentials μ B . For the strangeness neutral case ( μ S = 0) at fixed ratio of electric charge to baryon number density ( n Q n B = 0.4 ), which is appropriate for a comparison with heavy ion collisions, we present results for κ B σ 2 B , S B σ 3 B / M B , κ H B σ 4 B and S H B σ 5 B / M B on the crossover line for the chiral transition, T pc ( μ B ). Furthermore, continuum extrapolations for this pseudo-critical transition line have recently been reported by HotQCD up to baryon chemical potentials μ B ≃ 300 MeV [A. Bazavov, et al., Chiral crossover in QCD at zero and non-zero chemical potentials, Phys. Lett. B 795 (2019) 15–21. arXiv:1812.08235 .]. These cumulant ratios are of direct relevance for comparisons with corresponding ratios measured by STAR in the BES-I and II runs at beam energies s NN ≥ 20 GeV . In particular, we point out that recent high statistics results on skewness and kurtosis of net-baryon number distributions obtained by STAR at s NN = 54.4 GeV put strong constraints on freeze-out parameters and are consistent with predictions from thermal QCD.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2021

Accurate Determination of the Neutron Skin Thickness of Pb 208 through Parity-Violation in Electron Scattering

We report a precision measurement of the parity-violating asymmetry A PV in the elastic scattering of longitudinally polarized electrons from 208 Pb. We measure A PV = 550 ± 16 (stat) ±8 (syst) parts per billion, leading to an extraction of the neutral weak form factor F W (Q 2 = 0.00616 GeV 2 ) = 0.368 ± 0.013. Combined with our previous measurement, the extracted neutron skin thickness is R n -R p = 0.283 ± 0.071 fm. The result also yields the first significant direct measurement of the interior weak density of 208 Pb: ρ$^0_W$ = -0.0796 ± 0.0036(exp) ± 0.0013(theo) fm -3 leading to the interior baryon density ρ$^0_b$ = 0.1480 ± 0.0036(exp) ± 0.0013(theo) fm -3 . Finally, the measurement accurately constrains the density dependence of the symmetry energy of nuclear matter near saturation density, with implications for the size and composition of neutron stars.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

Experimental Determination of 𝛼 Widths of 21 Ne Levels in the Region of Astrophysical Interest: New 17 O +𝛼 Reaction Rates and Impact on the Weak 𝑠 Process

The efficiency of the weak 𝑠 process in low-metallicity rotating massive stars depends strongly on the rates of the competing 17 O ⁡(𝛼,𝑛)⁢ 20 Ne and 17 O ⁡(𝛼,𝛾)⁢ 21 Ne reactions that determine the potency of the 16 O neutron poison. Their reaction rates are poorly known in the astrophysical energy range of interest for core helium burning in massive stars because of the lack of spectroscopic information (partial widths, spin parities) for the relevant states in the compound nucleus 21 Ne . In this Letter, we report on the first experimental determination of the 𝛼-particle spectroscopic factors and partial widths of these states using the 17 O ⁡( 7 Li, 𝑡)⁢ 21 Ne 𝛼-transfer reaction. With these the 17 O ⁡(𝛼, 𝑛)⁢ 20 Ne and 17 O ⁡(𝛼, 𝛾)⁢ 21 Ne reaction rates were evaluated with uncertainties reduced by a factor more than 3 with respect to previous evaluations and the present 17 O ⁡(𝛼, 𝑛)⁢ 20 Ne reaction rate is more than 20 times larger. Finally, the present (𝛼, 𝑛)/(𝛼, 𝛾) rate ratio favors neutron recycling and suggests an enhancement of the weak 𝑠 process in the Zr-Nd region by more than 1.5 dex in metal-poor rotating massive stars.

direct reactions↗
DOE OSTI2021

Time-domain Modulation of HD 189733 Activities by Its Planet

Star–planet interaction can be studied by analyzing exoplanetary orbit and stellar rotation modulations of the transit emissions from exoplanetary systems. Here we carry out a time-domain analysis of the multiband activities of the HD 189733 star–planet system observed in X-ray, atomic lines, and broadband spectra reported in the literature. We find that the number of activities occuring at beat angles (of the planetary orbit and the stellar rotation) concentrating on a sector with a width of 108° are significantly larger than expected from a uniform distribution of activities, which indicates the existence of a major stellar active magnetic field region. The concentration of activities in this active magnetic field region shows their possible origins from the magnetic field interaction between HD 189733 and its close planet HD 189733 b.

47 OTHER INSTRUMENTATION↗
DOE OSTI2021

High tide: a systematic search for ellipsoidal variables in ASAS-SN

ABSTRACT The majority of non-merging stellar mass black holes are discovered by observing high energy emission from accretion processes. Here, we pursue the large, but still mostly unstudied population of non-interacting black holes and neutron stars by searching for the tidally induced ellipsoidal variability of their stellar companions. We start from a sample of about 200 000 rotational variables, semiregular variables, and eclipsing binary stars from the All-Sky Automated Survey for Supernovae. We use a χ2 ratio test followed by visual inspection to identify 369 candidates for ellipsoidal variability. We also discuss how to combine the amplitude of the variability with mass and radius estimates for observed stars to calculate a minimum companion mass, identifying the most promising candidates for high mass companions.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

Josephson currents in neutron stars

We demonstrate that the interface between S-wave and P-wave paired superfluids in neutron stars induces a neutron supercurrent, a charge-neutral analog of the Josephson junction effect in electronic superconductors. The proton supercurrent entrainment by the neutron superfluid generates, in addition to the neutral supercurrent, a charged current across the interface. Beyond this stationary effect, the motion of the neutron vortex lines responding to secular changes in the neutron star’s rotation rate induces a time-dependent oscillating Josephson current across this interface when proton flux tubes are dragged along with them. We show that such motion produces radiation from the interface once clusters of proton flux tubes intersect the interface. The power of radiation exceeds by orders of magnitude the Ohmic dissipation of currents in neutron stars. As a result, this effect appears to be phenomenologically significant enough to heat the star and alter its cooling rate during the photon cooling era.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2026

Beam-energy dependence of correlations between mean transverse momentum and anisotropic flow of charged particles in Au+Au collisions at RHIC

The correlation between the mean transverse momentum, [ p T ], and the squared anisotropic flow, $v^2_n$, on an event-by-event basis has been suggested to be influenced by the initial conditions in heavy-ion collisions. We present measurements of the variances and covariance of [ p T ] and $v^2_n$, along with their dimensionless ratio, for Au+Au collisions at various beam energies: $\sqrt{s_{NN}}$ = 14.6, 19.6, 27, 54.4, and 200 GeV. Our measurements reveal a distinct energy-dependent behavior in the variances and covariances. In addition, the dimensionless ratio displays a similar behavior across different beam energies. We compare our measurements with hydrodynamic models and similar measurements from Pb+Pb collisions at the Large Hadron Collider (LHC). These findings provide valuable insights into the beam energy dependence of the specific shear viscosity ( η/s ) and initial-state effects, allowing for differentiating between different initial-state models.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗