Parton degrees of freedom in PDFs from the hadronic tensor and large momentum effective theory
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
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Results for “Effective theory”
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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Strange quark helicity in the proton from chiral effective theory
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73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Single transverse-spin asymmetry and Sivers function in large momentum effective theory
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Octet and decuplet baryon self-energies in relativistic SU(3) chiral effective theory
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74 ATOMIC AND MOLECULAR PHYSICS↗
Factorization at subleading power, Sudakov resummation, and endpoint divergences in soft-collinear effective theory
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Computing light-front wave functions without light-front quantization: A large-momentum effective theory approach
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79 ASTRONOMY AND ASTROPHYSICS↗
BChPT x 1/N c in SU(3): a more effective theory
The chiral and 1/Nc1/N_c1/Nc expansions are combined in the description of low energy baryons. The combination furnishes a better behaved expansion, consequence of exactly eliminating large terms that violate the 1/Nc1/N_c1/Nc expansion and which are typical of formulations of BChPT where consistency with the large NcN_cNc limit is disregarded. The improvements are particularly dramatic in the case of SU(3). The general framework is outlined and applications to the vector charges and axial couplings are presented. A discussion of Lattice QCD results with three quark flavors for axial couplings is presented
Goity, Jose Luis↗
ETHOS – an Effective Theory of Structure Formation: detecting dark matter interactions through the Lyman-α forest
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Sownak Bose↗
Comparison of forward flight effects theory of A. Michalke and U. Michel with measured data
The scaling laws of a Michalke and Michel predict flyover noise of a single stream shock free circular jet from static data or static predictions. The theory is based on a farfield solution to Lighthill's equation and includes density terms which are important for heated jets. This theory is compared with measured data using two static jet noise prediction methods. The comparisons indicate the theory yields good results when the static noise levels are accurately predicted.
Rawls, J. W., Jr.↗
Towards an Effective Theory of Reformulation: Semantics - Part 1
This paper describes an investigation into the structure of representations of sets of actions, utilizing semigroup theory. The goals of this project are twofold: to shed light on the relationship between tasks and representations, leading to a classification of tasks according to the representations they admit; and to develop techniques for automatically transforming representations so as to improve problem-solving performance. A method is demonstrated for automatically generating serial algorithms for representations whose actions form a finite group. This method is then extended to representations whose actions form a finite inverse semigroup.
Benjamin, D. Paul↗
Stability of hairy black holes in shift-symmetric scalar-tensor theories via the effective field theory approach
Shift-symmetric Horndeski theories admit an interesting class of Schwarzschild-de Sitter black hole solutions exhibiting time-dependent scalar hair. The properties of these solutions may be studied via a bottom-up effective field theory (EFT) based on the background symmetries. This is in part possible by making use of a convenient coordinate choice — Lemaître-type coordinates — in which the profile of the Horndeski scalar field is linear in the relevant time coordinate. We construct this EFT, and use it to understand the stability of hairy black holes in shift-symmetric Horndeski theories, providing a set of constraints that the otherwise-free functions appearing in the Horndeski Lagrangian must satisfy in order to admit stable black hole solutions. The EFT is analyzed in the decoupling limit to understand potential sources of instability. Further, we also perform a complete analysis of the EFT with odd-parity linear perturbations around general spherically symmetric space-time.
79 ASTRONOMY AND ASTROPHYSICS↗
Electroweak Currents from Chiral Effective Field Theory
Since the pioneering work of Weinberg, Chiral Effective Field Theory (EFT) has been widely and successfully utilized in nuclear physics to study many-nucleon interactions and associated electroweak currents. Here, nuclear EFT has now developed into an intense field of research and is applied to study light to medium mass nuclei. In this contribution, we focus on the development of electroweak currents from EFT and present applications to selected nuclear electroweak observables.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Temperature effects on the neutron matter equation of state obtained from chiral effective field theory
Temperature effects on the neutron matter equation of state (EoS) are investigated in the framework of chiral effective field theory. Recently, state-of-the-art chiral two-nucleon forces are applied from third to fifth order in the chiral expansion together with chiral three-nucleon forces, allowing for a determination of the truncation error of the theoretical predictions. The thermodynamic quantities considered include the chemical potential, the internal energy, the entropy, and the free energy. In general, good order-by-order convergence of all predictions is observed. As to be expected, temperature effects are largest at low density. Finally, the temperature dependence of the chiral three-nucleon force turns out to be weak.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Resonant shattering flares as asteroseismic tests of chiral effective field theory
Chiral effective field theory (𝜒EFT) has proved to be a powerful microscopic framework for predicting the properties of neutron-rich nuclear matter with quantified theoretical uncertainties up to about twice the nuclear saturation density. Tests of 𝜒EFT predictions are typically performed at low densities using nuclear experiments, with neutron star (NS) constraints only being considered at high densities. In this work, we discuss how asteroseismic quasinormal modes within NSs could be used to constrain specific matter properties at particular densities not just the integrated quantities to which bulk NS observables are sensitive. We focus on the crust-core interface mode, showing that measuring this mode's frequency would provide a meaningful test of 𝜒EFT at densities around half the saturation density. Conversely, we use nuclear matter properties predicted by 𝜒EFT to estimate that this mode's frequency is around 185 ± 50Hz. Asteroseismic observables such as resonant phase shifts in gravitational-wave signals and multimessenger resonant shattering flare timings, therefore, have the potential to provide useful tests of 𝜒EFT.
effective field theory↗
Revisiting proton–proton fusion in chiral effective field theory
We calculate the S-factor for proton–proton fusion using chiral effective field theory interactions and currents. By performing order-by-order calculations with a variety of chiral interactions that are regularized and calibrated in different ways, we assess the uncertainty in the S-factor from the truncation of the effective field theory expansion and from the sensitivity of the S-factor to the short-distance axial current determined from three- and four-nucleon observables. We find that S(0) = (4.100 ± 0.024(syst) ± 0.013(stat) ± 0.008(g$_{A}$)) × 10$^{−23}$ MeV fm$^{2}$, where the three uncertainties arise, respectively, from the truncation of the effective field theory expansion, use of the two-nucleon axial current fit to few-nucleon observables and variation of the axial coupling constant within the recommended range. The increased value of S(0) compared to previous calculations is mainly driven by an increase in the recommended value for the axial coupling constant and is in agreement with a recent analysis based on pionless effective field theory.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Dilute Fermi gas at fourth order in effective field theory
Using effective field theory methods, we calculate for the first time the complete fourth-order term in the Fermi-momentum or k F a s expansion for the ground-state energy of a dilute Fermi gas. The convergence behavior of the expansion is examined for the case of spin one-half fermions and compared against quantum Monte-Carlo results, showing that the Fermi-momentum expansion is well-converged at this order for |k F a s | ≲ 0.5.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Ab initio nucleon-nucleus elastic scattering with chiral effective field theory uncertainties
Effective interactions for nucleon-nucleus elastic scattering from first principles require the use of the same nucleon-nucleon interaction in the structure and reaction calculations and a consistent treatment of the relevant operators at each order. Systematic investigations of the effect of truncation uncertainties of chiral nucleon-nucleon ( N N ) forces have been carried out for scattering observables in the two- and three-nucleons system as well as for bound-state properties of light nuclei. Here we extend this type of study to proton and neutron elastic scattering for 16 O and 12 C. Using the frameworks of the spectator expansion of multiple scattering theory as well as the no-core shell model, we employ one specific chiral interaction from the LENPIC collaboration and consistently calculate the leading-order effective nucleon-nucleus interaction up to the third chiral order, from which we extract elastic scattering observables. Then we apply pointwise as well as correlated uncertainty quantification for the estimation of the chiral truncation error. We calculate and analyze proton elastic scattering observables for 16 O and 12 C as well as neutron elastic scattering observables for 12 C between 65 and 185 MeV projectile kinetic energy. We find in all cases qualitatively similar results for the chiral truncation uncertainties as in few-body systems and assess them using similar diagnostic tools. The order-by-order convergence of the scattering observables for 16 O and 12 C is very reasonable around 100 MeV, while for higher energies the chiral expansion parameter becomes too large for convergence. Comparing proton and neutron differential cross sections reveals that their description is comparable up to around 100 MeV. Here, we also find a nearly perfect correlation between the differential cross section for neutron scattering and the N N Wolfenstein amplitudes for small momentum transfers. The diagnostic tools for studying order-by-order convergence in observables in few-body systems can be employed for observables in nucleon-nucleus scattering with only minor modifications provided the momentum scale in the problems is not too large. We also find that the chiral N N interaction on which our study is based gives a very good description of differential cross sections for 16 O and 12 C as low as 65-MeV projectile energy, particularly in the forward direction. In addition, the very forward direction of the neutron differential cross section mirrors the behavior of the N N interaction amazingly well.
6 ≤ A ≤ 19↗