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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 397 records · Page 22
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DOE OSTI2022

Shock revival in core-collapse supernovae assisted by heavy axionlike particles

We report axionlike particles (ALPs) are a class of hypothetical pseudoscalar particles which feebly interact with ordinary matter. The hot plasma of core-collapse supernovae is a possible laboratory to explore physics beyond the standard model including ALPs. Once produced, some of the ALPs can be absorbed by the supernova matter and affect energy transfer. In this study, we calculate the ALP emission in core-collapse supernovae and the backreaction on supernova dynamics consistently. It is found that the stalled bounce shock can be revived if the coupling between ALPs and photons is as high as $g_{aγ}$ ~ 10 -9 GeV -1 and the ALP mass is 40–400 MeV. Most of the models result in more energetic explosions than the average observed supernova. While this can be used to place constraints on those ALPs, long-term simulations across multiple progenitors need to be further investigated to place robust limits.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Investigation of CMB constraints for dark matter-helium scattering

In this work, we study dark matter-helium scattering in the early Universe and its impact on constraints from cosmic microwave background (CMB) anisotropy measurements. We describe possible theoretical frameworks for dark matter-nucleon interactions via a scalar, pseudoscalar, or vector mediator; such interactions give rise to hydrogen and helium scattering, with cross sections that have a power-law dependence on relative velocity. Within these frameworks, we consider three scenarios: dark matter coupling to only neutrons, to only protons, and to neutrons and protons with equal strength. For these various cases, we use Planck 2018 temperature, polarization, and lensing anisotropy data to place constraints on dark matter scattering with hydrogen and/or helium for dark matter masses between 10 keV and 1 TeV. For any model that permits both helium and hydrogen scattering with a non-negative power-law velocity dependence, we find that helium scattering dominates the constraint for dark matter masses well above the proton mass. Furthermore, we place the first CMB constraints on dark matter that scatters dominantly/exclusively with helium in the early Universe.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Search for direct CP violation in charged charmless B→PV decays

Measurements of C P asymmetry in charmless B → P V decays are presented, where P and V denote a pseudoscalar and a vector meson, respectively. Five different B → P V decays from four final states, B ± → π ± π + π - , B ± → K ± π + π - , B ± → K ± K + K - and B ± → π ± K + K - are analyzed. The measurements are based on a method that does not require full amplitude analyses, and are performed using proton-proton collision data at a center-of-mass energy of 13 TeV collected by LHCb between 2015 and 2018, corresponding to an integrated luminosity of 5.9 fb - 1 . In the π + π - P -wave, in the region dominated by the B ± → ρ ( 770 ) 0 K ± decay, a C P asymmetry of A C P = + 0.150 ± 0.019 ± 0.011 is measured, where the first uncertainty is statistical and the second is systematic. This is the first observation of C P violation in this process. For the other four decay channels, in regions dominated by the B ± → ρ ( 770 ) 0 π ± , B ± → K ( ¯ ) * ( 892 ) 0 π ± , B ± → K ( ¯ ) * ( 892 ) 0 K ± and B ± → Φ ( 1020 ) K ± decays, C P asymmetries in the P -wave compatible with zero are measured.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

Constraints on axionlike polarization oscillations in the cosmic microwave background with POLARBEAR

Very light pseudoscalar fields, often referred to as axions, are compelling dark matter candidates and can potentially be detected through their coupling to the electromagnetic field. Recently a novel detection technique using the cosmic microwave background (CMB) was proposed, which relies on the fact that the axion field oscillates at a frequency equal to its mass in appropriate units, leading to a time-dependent birefringence. For appropriate oscillation periods this allows the axion field at the telescope to be detected via the induced sinusoidal oscillation of the CMB linear polarization. Furthermore, we search for this effect in two years of POLARBEAR data. We do not detect a signal and place a median 95% upper limit of 0.65° on the sinusoid amplitude for oscillation frequencies between 0.02 days -1 and 0.45 -1 days, which corresponds to axion masses between 9.6 × 10 -22 eV and 2.2 × 10 -20 eV. Under the assumptions that 1) the axion constitutes all the dark matter and 2) the axion field amplitude is a Rayleigh-distributed stochastic variable, this translates to a limit on the axion-photon coupling g Φγ < 2.4 × 10 -11 GeV -1 × (m Φ /10 -21 eV).

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Nucleon isovector axial form factors

We present results for the isovector axial vector form factors obtained using thirteen 2 + 1 + 1 -flavor highly improved staggered quark (HISQ) ensembles generated by the MILC collaboration. The calculation of nucleon two- and three-point correlation functions has been done using Wilson-clover fermions. In the analysis of these data, we quantify the sensitivity of the results to strategies used for removing excited state contamination and invoke the partially conserved axial current relation between the form factors to choose between them. Our data driven analysis includes removing contributions from multihadron N π states that make significant contributions. Our final results are g A = 1.292 ( 53 ) stat ( 24 ) sys for the axial charge; g S = 1.085 ( 50 ) stat ( 103 ) sys and g T = 0.991 ( 21 ) stat ( 10 ) sys for the scalar and tensor charges; ⟨ r A 2 ⟩ = 0.439 ( 56 ) stat ( 34 ) sys fm 2 for the mean squared axial charge radius, g P * = 9.03 ( 47 ) stat ( 42 ) sys for the induced pseudoscalar charge; and g π N N = 14.14 ( 81 ) stat ( 85 ) sys for the pion-nucleon coupling. We also provide a parametrization of the axial form factor G A ( Q 2 ) over the range 0 ≤ Q 2 ≤ 1 GeV 2 for use in phenomenology and a comparison with other lattice determinations. We find that the various lattice data agree within 10% but are significantly different from the extraction of G A ( Q 2 ) from the ν -deuterium scattering data. Published by the American Physical Society 2024

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Anomalous interactions between mesons with nonzero spin and glueballs

Topologically nontrivial fluctuations control the anomalous interactions for the η and η ′ pseudoscalar mesons. We consider the anomalous interactions for mesons with higher spin, the heterochiral nonets with J P C = 1 + − and 2 − + . Under the approximation of a dilute gas of instantons, the mixing angle between nonstrange and strange mesons decreases strongly as J increases, and oscillates in sign. Anomalous interactions also open up new, rare decay channels. For glueballs, anomalous interactions indicate that the X ( 2600 ) state is primarily gluonic. Published by the American Physical Society 2024

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

Glue in hadrons at medium resolution and the QCD instanton vacuum

We discuss a general framework for the evaluation of the gluonic form factors in light hadrons at low momentum transfer, in the QCD instanton vacuum. At medium resolution of the order of the inverse mean instanton size, the glue is mostly localized in single or pairs of pseudoparticles and globally constrained by the fluctuations of their topological charges. These pseudoparticles trap light quarks, giving rise to emerging multiflavor ’t Hooft interactions. We explicitly evaluate the gluonic scalar, pseudoscalar, energy-momentum tensor (EMT), and the leading C -odd and C -even three-gluon hadronic form factors, at next to leading order in the instanton density, including molecular clusters of like and unlike instantons. We use the results for the EMT to address the contribution of the gluons in Ji’s mass and spin sum rules, at low resolution. When evolved, our results for the mass and spin composition of the nucleon are shown to be in good agreement with the recently reported lattice results at higher resolution. Published by the American Physical Society 2024

Astronomy & Astrophysics↗
DOE OSTI2024

Nonlocal chiral contributions to generalized parton distributions of the proton at nonzero skewness

We compute the one-loop contributions to spin-averaged generalized parton distributions (GPDs) in the proton from pseudoscalar mesons with intermediate octet and decuplet baryon states at nonzero skewness. Our framework is based on nonlocal covariant chiral effective theory, with ultraviolet divergences regularized by introducing a relativistic regulator derived consistently from the nonlocal Lagrangian. Using the splitting functions calculated from the nonlocal Lagrangian, we find the nonzero skewness GPDs from meson loops by convoluting with the phenomenological pion GPD and the generalized distribution amplitude, and verify that these satisfy the correct polynomiality properties. We also compute the lowest two moments of GPDs to quantify the meson loop effects on the Dirac, Pauli, and gravitational form factors of the proton.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Constraining neutrinophilic mediators at FASER ν , FLArE, and FASER ν 2

High energy collider neutrinos have been observed for the first time by the FASER ν experiment. The detected spectrum of collider neutrinos scattering off nucleons can be used to probe neutrinophilic mediators with GeV-scale masses. We find that constraints on the pseudoscalar (axial vector) neutrinophilic mediator are close to the scalar (vector) case since they have similar cross section in the neutrino massless limit. We perform an analysis on the measured muon spectra at FASER ν , and find that the bounds on the vector mediator from the current FASER ν data are comparable to the existing bounds at m Z ′ ≈ 0.2 GeV . We also study the sensitivities to a neutrinophilic mediator at future Forward Physics Facilities including FLArE and FASER ν 2 by using both the missing transverse momentum and the charge identification information. We find that FLArE and FASER ν 2 can impose stronger bounds on both the scalar and vector neutrinophilic mediators than the existing bounds. The constraints on the scalar mediator can reach 0.08 (0.1) for m ϕ ≲ 1 GeV with (without) muon charge identification at FASER ν 2 . Published by the American Physical Society 2024

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Search for diphoton decays of an axionlike particle in radiative J / ψ decays

We search for the diphoton decay of a light pseudoscalar axionlike particle, a , in radiative J / ψ decays, using 10 10 J / ψ events collected with the BESIII detector. We find no evidence of a signal and set upper limits at the 95% confidence level on the product branching fraction B ( J / ψ → γ a ) × B ( a → γ γ ) and the axionlike particle photon coupling constant g a γ γ in the ranges of ( 3.7 – 48.5 ) × 10 − 8 and ( 2.2 – 101.8 ) × 10 − 4 GeV − 1 , respectively, for 0.18 ≤ m a ≤ 2.85 GeV / c 2 . These are the most stringent limits to date in this mass region. Published by the American Physical Society 2024

Astronomy & Astrophysics↗
DOE OSTI2025

Effective field theory for radiative corrections to charged-current processes. II. Axial-vector coupling

Here we discuss the hadronic structure-dependent radiative corrections to the axial-vector coupling that controls single-nucleon weak charged-current processes—commonly denoted by 𝑔 𝐴 . We match the Standard Model at the GeV scale onto chiral perturbation theory at next-to-leading order in the one-nucleon sector, in the presence of electromagnetic and weak interactions. As a result, we provide a representation for the corrections to 𝑔 𝐴 in terms of infrared finite convolutions of simple kernels with the single-nucleon matrix elements of time-ordered products of two and three quark bilinears (vector, axial-vector, and pseudoscalar). We discuss strategies to determine the required nonperturbative input from data, lattice-QCD (+QED), and possibly hadronic models. This work paves the way for a precise comparison of the values of the ratio 𝑔 𝐴 ⁡/𝑔 𝑉 extracted from experiment and from lattice QCD, which constrain physics beyond the Standard Model.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

Interacting mesons as degrees of freedom in a chiral model

Here, we study the equation of state of hot and dense hadronic matter using an extended chiral mean field (CMF) model framework where the addition is the inclusion of interactions of thermally excited mesons. This is implemented by calculating the in-medium masses of pseudoscalar and vector mesons, obtained through the explicit chiral symmetry-breaking and vector-interaction terms in the Lagrangian, respectively, prior to applying the mean-field approximation. As a result, the in-medium meson contributions generate a feedback term to the CMF’s equations of motion, which then modifies the equation of state. With this improvement, we quantify the effect on the equation of state of strongly interacting matter through comparisons with state-of-the-art lattice QCD results and other hadronic models like the hadron resonance gas model. We find that the results of the updated hadronic CMF model with an improved meson description (mCMF) provide a better agreement with lattice-QCD data for thermodynamic state variables across a wide range of temperatures and baryon chemical potentials.

phenomenology↗
DOE OSTI2011

Constraining the photon-axion coupling constant with magnetic white dwarfs

The light pseudoscalar particle, dubbed the axion, borne out of the Peccei-Quinn solution to the strong CP problem in QCD remains elusive. One avenue of inferring its existence is through its coupling to electromagnetic radiation. So far, laboratory experiments have dedicated all efforts to detect the axion in the mass range 10{sup -6}<m{sub a}<10{sup -3} eV with a photon-axion coupling strength g{sub a}{gamma}{gamma}<10{sup -10} GeV{sup -1}, where the limits are derived from astrophysical considerations. In this study, we present a novel way of constraining g{sub a}{gamma}{gamma} by looking at the level of linear polarization in the radiation emerging from magnetic white dwarfs. We find that photon-axion oscillations in white dwarf magnetospheres can enhance the degree of linear polarization. Observing that most magnetic white dwarfs show only 5% linear polarization, we derive upper limits on g{sub a}{gamma}{gamma} for different axion masses.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Early LHC phenomenology of Yukawa-bound heavy QQ mesons

Current limits from the LHC on fourth generation quarks are already at the unitarity bound of 500 GeV or so. If they exist, the strong Yukawa couplings are turning nonperturbative, and may form bound states. We study the domain of m{sub b'} and m{sub t'} in the range of 500 to 700 GeV, where we expect binding energies are mainly of Yukawa origin, with QCD subdominant. To be consistent with electroweak precision tests, the t' and b' quarks have to be nearly degenerate, exhibiting a new 'isospin'. Comparing relativistic expansion with a relativistic bound state approach, we find the most interesting is the production of a color octet, isosinglet vector meson (a 'gluon-prime') via qq-bar{yields}{omega}{sub 8}. Leading decay modes are {pi}{sub 8}{sup {+-}}W{sup {+-}}, {pi}{sub 8}{sup 0}Z{sup 0}, and constituent quark decay, with qq and tt-bar' and bb' subdominant. The color octet, isovector pseudoscalar {pi}{sub 8} meson decays via constituent quark decay, or to Wg. These decay rates are parameterized by the decay constant, the binding energy and mass differences, and V{sub tb'}. For small V{sub t'b}, one could have a spectacular signal of WWg, where a soft W accompanies a very massive Wg pair. In general, however, one has high multiplicity signals with b, W, and t jet substructures that are not so different from the t't-bar' and b'b-bar' search.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Excited upsilon radiative decays

Bottomonium S-wave states were studied using lattice NRQCD. Masses of ground and excited states were calculated using multiexponential fitting to a set of correlation functions constructed using both local and wavefunction-smeared operators. Three-point functions for M1 transitions between vector and pseudoscalar states were computed. Robust signals for transitions involving the first two excited states were obtained. The qualitative features of the transition matrix elements are in agreement with expectations. The calculated values of matrix elements for {Upsilon}(2S) and {Upsilon}(3S) decay are considerably larger than values inferred from measured decay widths.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Revisiting light neutralino scenarios in the MSSM

We revisit the case of a light neutralino lightest supersymmetric particle in the framework of the minimal supersymmetric standard model. We consider a model with 11 free parameters. We show that all scenarios where the annihilation of light neutralinos rely mainly on the exchange of a light pseudoscalar are excluded by direct detection searches and by Fermi measurements of the {gamma}-flux from dwarf spheroidal galaxies. On the other hand, we find scenarios with light sleptons that satisfy all collider and astroparticle physics constraints. In this case, the lower limit on the lightest supersymmetric particle mass is 12.6 GeV. We discuss briefly how the parameter space of the model could be further probed at the LHC.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Gluon-fusion contributions to {Phi}+2 jet production

In high energy hadronic collisions, a scalar or pseudoscalar Higgs boson, {Phi}=H, A, can be efficiently produced via gluon fusion, which is mediated by heavy quark loops. In this paper, we consider double real emission corrections to {Phi}=A production, which lead to a Higgs plus two-jet final state, at order {alpha}{sub s}{sup 4}. Full quark mass effects are considered in the calculation of scattering amplitudes for the CP-odd Higgs boson A, as induced by quark triangle-, box-, and pentagon-diagrams. They complement the analogous results for a CP-even Higgs boson H in Ref. [1]. Interference effects between loops with top and bottom quarks as well as between CP-even and CP-odd couplings of the heavy quarks are fully taken into account.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗