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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 OSTI2024

SIDIS at small x at next-to-leading order: Gluon contribution

We calculate the contribution of gluons to single inclusive hadron production at next-to-leading order (NLO) accuracy in deep inelastic scattering (DIS) at small x using the color glass condensate formalism. It is shown that the only divergence present is the standard collinear divergence, which is absorbed into scale evolution of quark-hadron fragmentation function. Our calculations are performed at finite N c and we provide general finite N c expressions for the structure of Wilson lines appearing in inclusive dihadron and single hadron production cross sections. We also comment on how one can obtain rapidity distribution of hadron multiplicities from our results. Published by the American Physical Society 2024

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS1972

Production cross sections for Lee-Wick massive electromagnetic bosons and for spin-zero and spin-one W bosons at high energies.

Production cross sections for three types of hypothetical particles are calculated in the presented paper. Several (Z, Z') cases were studied corresponding to elastic scattering off protons and neutrons (either free or embedded within a Fermi sea), coherent scattering off a nucleus, and inelastic scattering off a proton (in which case Z' denotes a nucleon resonance or hadronic system in the continuum). Detailed structure-function data are used to improve the accuracy of the inelastic scattering calculation. Results of calculations are given for beam energies between 50 and 10,000 GeV, and masses between 5 and 40 GeV for the massive Lee-Wick spin-1 boson. Cross sections were computed for resonant and semiweak processes. The production cross section of spin-zero weak intermediate bosons was found to be at least one order of magnitude smaller than for spin-1 weak bosons in nearly all regions of interest. The production cross section of spin-zero weak intermediate bosons for inelastic scattering off protons compares with that for elastic scattering in the regions of interest. In the case of massive spin-1 bosons and spin-1 weak intermediates, the main contribution to total production cross section off protons is elastic.

Linsker, R.↗
DOE OSTI2022

Measurement of H(e,e’) and D(e,e’) Cross-Sections for Bloom-Gilman Quark-Hadron Duality Study

The E12-10-002 experiment which ran in 2018 in Hall C at the Thomas Jefferson National Accelerator Facility measured the inclusive electron scattering cross-sections for hydrogen and deuterium. This was the first experiment conducted with the new Super High-Momentum Spectrometer and accompanying instrumentation. These measurements extend the previous Hall C measurements up to Q2 = 16 GeV2. This dissertation presents the analyses of the new detectors and shows the preliminary results for F2 structure function and the study of quark-hadron duality in the four nucleon-resonance regions.

Sun, Abel↗
DOE OSTI2023

Study of Nucleon Resonance Electroexcitations at Jefferson Lab

Nucleons are the most fundamental three-body systems in Nature. During the last decade crucial progress has been achieved in the exploration of the spectrum and the structure of nucleon resonances. Studies of exclusive ?N, ?+??p, K?, and K? electroproduction off protons on the evolution of the electrocouplings with photon virtuality Q2 using the CLAS spectrometer has revealed a complex interplay between an inner core of three dressed quarks surrounded by an external meson-baryon cloud. CLAS12 is the only facility capable of extending these results on the electrocouplings into the unexplored Q2 range, spanning the domain of quark momenta where ? 50% of hadron mass is generated. The increase of the CEBAF energy and the upgrade of the CLAS12 spectrometer to measure exclusive electroproduction channels at higher luminosity and photon virtualities will offer a unique opportunity to explore how the dominant part of hadron mass and the bound three-quark structure of the resonant states emerge from QCD.

Achenbach, Patrick↗
DOE OSTI2022

Measurement of the nuclear modification factor for muons from charm and bottom hadrons in Pb+Pb collisions at 5.02 TeV with the ATLAS detector

Heavy-flavour hadron production provides information about the transport properties and microscopic structure of the quark–gluon plasma created in ultra-relativistic heavy-ion collisions. A measurement of the muons from semileptonic decays of charm and bottom hadrons produced in Pb+Pb and pp collisions at a nucleon–nucleon centre-of-mass energy of 5.02 TeV with the ATLAS detector at the Large Hadron Collider is presented. The Pb+Pb data were collected in 2015 and 2018 with sampled integrated luminosities of 208 μb –1 and 38 μb –1 , respectively, and pp data with a sampled integrated luminosity of 1.17 pb –1 were collected in 2017. Muons from heavy-flavour semileptonic decays are separated from the light-flavour hadronic background using the momentum imbalance between the inner detector and muon spectrometer measurements, and muons originating from charm and bottom decays are further separated via the muon track's transverse impact parameter. Differential yields in Pb+Pb collisions and differential cross sections in pp collisions for such muons are measured as a function of muon transverse momentum from 4 GeV to 30 GeV in the absolute pseudorapidity interval |n| < 2. Nuclear modification factors for charm and bottom muons are presented as a function of muon transverse momentum in intervals of Pb+Pb collision centrality. The bottom muon results are the most precise measurement of b quark nuclear modification at low transverse momentum where reconstruction of B hadrons is challenging. The measured nuclear modification factors quantify a significant suppression of the yields of muons from decays of charm and bottom hadrons, with stronger effects for muons from charm hadron decays.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

O 16 O 16 collisions at energies available at the BNL Relativistic Heavy Ion Collider and at the CERN Large Hadron Collider comparing α clustering versus substructure

Collisions of . light and heavy nuclei in relativistic heavy-ion collisions have been shown to be sensitive to nuclear structure. With a proposed 16 O 16 O run at the CERN Large Hadron Collider (LHC) and at the BNL Relativistic Heavy Ion Collider (RHIC) we study the potential for finding α clustering in 16 O. Here we use the state-of-the-art iEBE-VISHNU package with 16 O nucleonic configurations from ab initio nuclear lattice simulations. This setup was tuned using a Bayesian analysis on p Pb and PbPb systems. We find that the 16 O 16 O system always begins far from equilibrium and that at LHC and RHIC it approaches the regime of hydrodynamic applicability only at very late times. Finally, by taking ratios of flow harmonics we are able to find measurable differences between α-clustering, nucleonic, and subnucleonic degrees of freedom in the initial state.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

New opportunities for Insight into Emergence of Hadron Mass from Studies of Nucleon Resonance Electroexcitation

Understanding the emergence of hadron mass (EHM) represents one of the most challenging and still open problems in the Standard Model. Results of EHM studies from the nucleon resonance electroexcitation amplitudes (gvpN* electrocouplings) determined from exclusive meson electroproduction data measured with the CLAS detector will be presented in this talk. These CLAS data have provided the first and only available results on the evolution of the ?vpN* electrocouplings with photon virtuality Q2 up to 5 GeV2 for most nucleon resonances in the mass range up to 1.8 GeV. A successful description of the CLAS results on the Q2-evolution of the ?(1232)3/2+, N(1440)1/2+, and ?(1600)3/2+ electrocouplings achieved within the CSM approach by employing the same dressed quark mass function inferred from the QCD Lagrangian, which also provided a successful description of the pion elastic electromagnetic form factor and PDF, and nucleon elastic form factor, conclusively demonstrated the capability of gaining insight into EHM. The expected results from the CLAS12 detector on the Q2-evolution of the gvpN* electrocouplings for all prominent resonances in the mass range up to 2 GeV at the still almost unexplored range of Q2>5 GeV2 will allow us to place tight constraints on the dressed quark mass function in the range of quark momenta where the substantial part of hadron mass ~50% is expected to be generated. Consistent results on the momentum dependence of the dressed quark mass obtained from analyses of the ?vpN* electrocouplings of nucleon resonances of different structure will validate insight into EHM in a nearly model-independent way, allowing us to address key open problems in hadron physics on the emergence of hadron mass and nucleon resonance structure from QCD.

Mokeev, Viktor↗
DOE OSTI2025

Finite- and infinite-volume study of DDπ scattering

We develop a comprehensive framework for extracting the pole position and properties of the doubly-charmed tetraquark $T$$^{+}_{cc}$(3875) from lattice QCD data using the relativistic three-particle formalism. This approach incorporates the effect of the one-pion exchange diagram in DDπ and DD ∗ scattering, making it applicable at energies coinciding with the left-hand cut in the partial-wave projected DD ∗ amplitude. We present an example application of this framework to existing lattice QCD data at mπ = 280 MeV. We solve the integral equations describing the DDπ reaction, use LSZ reduction to determine the corresponding DD ∗ amplitude, and find the values of the infinite-volume two- and three-body K matrices that lead to agreement with lattice DD ∗ phase shifts within their uncertainties. Using these K matrices in the three-particle quantization condition, we describe the finite- volume DD ∗ spectrum and find good agreement with the lattice QCD energies. Our results suggest that, at this pion mass, the tetraquark appears as a pair of subthreshold complex poles whose precise location strongly depends on the value of the DDπ three-particle K matrix.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

The three-pion K -matrix at NLO in ChPT

The three-particle K-matrix, Κ df,3 , is a scheme-dependent quantity that parametrizes short-range three-particle interactions in the relativistic-field-theory three-particle finite-volume formalism. In this work, we compute its value for systems of three pions in all isospin channels through next-to-leading order in Chiral Perturbation Theory, generalizing previous work done at maximum isospin. We obtain analytic expressions through quadratic order (or cubic order, in the case of zero isospin) in the expansion about the three-pion threshold.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Evolution of parton distribution functions in the short-distance factorization scheme

Lattice QCD offers the possibility of computing parton distributions from first principles, although not in the usual $\overline{MS}$ factorization scheme. Calculations are therefore matched to $\overline{MS}$ using a perturbative procedure which is the source of significant uncertainty within the currently accessible kinematics. We present the possibility of computing the z 2 evolution of non-singlet pseudo-parton distribution functions within the short factorization scheme in a numerically improvable way. The goal is to have tools to evolve a calculation to a scale where perturbative uncertainties are less pronounced. We compare a numerical extraction of the evolution operator from lattice data to the computation of z 2 dependence in perturbation theory. Finally, we discuss how this numerical work may be extended to address the two-scale problem that arises when the Ioffe time range must be made large to extend the reach of the calculation of the pseudo-PDF to smaller values of the momentum fraction.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Interactions of πK, ππK and KKπ systems at maximal isospin from lattice QCD

We study the interactions of systems of two and three nondegenerate mesons composed of pions and kaons at maximal isospin using lattice QCD, specifically $π^+K^+, π^+π^+K^+$ and $K^+K^+π^+$. Utilizing the stochastic LapH method, we determine the spectrum of these systems on two CLS $N_f$ = 2 + 1 ensembles with pion masses of 200 MeV and 340 MeV, and include many levels in different momentum frames. We constrain the K matrices describing two- and three-particle interactions by fitting the spectrum to the results predicted by the finite-volume formalism, including up to p waves. This requires also results for the $π^+π^+$ and $K^+K^+$ spectrum, which have been obtained previously on the same configurations. We explore different fitting strategies, comparing fits to energy shifts with fits to energies boosted to the rest frame, and also comparing simultaneous global fits to all relevant two- and three-particle channels to those where we first fit twoparticle channels and then add in the three-particle information. We provide the first determination of the three-particle K matrix in $π^+π^+K^+$ and $K^+K^+π^+$ systems, finding statistically significant nonzero results in most cases. We include s and $\textit{p}$ waves in the K matrix for $π^+K^+$ scattering, finding evidence for an attractive p-wave scattering length. We compare our results to Chiral Perturbation Theory, including an investigation of the impact of discretization errors, for which we provide the leading order predictions obtained using Wilson Chiral Perturbation Theory.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2023

The isospin-3 three-particle K -matrix at NLO in ChPT

The three-particle K-matrix, K df,3 , is a scheme-dependent quantity that parametrizes short-range three-particle interactions in the relativistic-field-theory three-particle finite-volume formalism. In this work, we compute its value for systems of three pions at maximal isospin through next-to-leading order (NLO) in Chiral Perturbation Theory (ChPT). We compare the values to existing lattice QCD results and find that the agreement between lattice QCD data and ChPT in the first two coefficients of the threshold expansion of K df,3 is significantly improved with respect to leading order once NLO effects are incorporated.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

A lattice study of ππ scattering at large N c

We present the first lattice study of pion-pion scattering with varying number of colors, N c . We use lattice simulations with four degenerate quark flavors, N f = 4, and N c = 3 – 6. We focus on two scattering channels that do not involve vacuum diagrams. These correspond to two irreducible representations of the SU(4) flavor group: the fully symmetric one, SS, and the fully antisymmetric one, AA. The former is a repulsive channel equivalent to the isospin-2 channel of SU(2). By contrast, the latter is attractive and only exists for N f ≥ 4. A representative state is (|D$^{+}_{s}$π + > – | D + K + >)/√2. Using Lüscher’s formalism, we extract the near-threshold scattering amplitude and we match our results to Chiral Perturbation Theory (ChPT) at large N c . For this, we compute the analytical U(N f ) ChPT prediction for two-pion scattering, and use the lattice results to constrain the N c scaling of the relevant low-energy couplings.

1/N Expansion↗
DOE OSTI2024

Incorporating DD π effects and left-hand cuts in lattice QCD studies of the T cc (3875) +

We generalize the relativistic field-theoretic three-particle finite-volume scattering formalism to describe generic DDπ systems in the charm C = 2 sector. This includes the isospin-0 channel, in which the recently discovered doubly-charmed tetraquark T cc (3875) + is expected to manifest as a pole in the DDπ → DDπ scattering amplitude. The formalism presented here can also be applied to lattice QCD settings in which the D * is bound and, in particular, remains valid below the left-hand cut in DD * scattering, thus resolving an issue in previous analyses of lattice-determined finite-volume energies.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Three relativistic neutrons in a finite volume

We generalize the relativistic field-theoretic (RFT) three-particle finite-volume formalism to systems of three identical, massive, spin-1/2 fermions, such as three neutrons. This allows, in principle, for the determination of the three-neutron interaction from the finite-volume spectrum of three-neutron states, which can be obtained from lattice QCD calculations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Three-particle formalism for multiple channels: the ηππ + $ K\overline{K}\pi $ system in isosymmetric QCD

We generalize previous three-particle finite-volume formalisms to allow for multiple three-particle channels. For definiteness, we focus on the two-channel ηππ and $ K\overline{K}\pi $ system in isosymmetric QCD, considering the positive G parity sector of the latter channel, and neglecting the coupling to modes with four or more particles. The formalism we obtain is thus appropriate to study the b 1 (1235) and η(1295) resonances. The derivation is made in the generic relativistic field theory approach using the time-ordered perturbation theory method. We study how the resulting quantization condition reduces to that for a single three-particle channel when one drops below the upper ($ K\overline{K}\pi $) threshold. We also present parametrizations of the three-particle K matrices that enter into the formalism.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

Off forward non- s -channel helicity conserving contributions to exclusive vector quarkonium production from the spin dependent BFKL Pomeron

A novel contribution to off forward, exclusive vector quarkonium production, γ(*)+p → V+p, at high energy is derived which corresponds to a t-channel exchange of a Balitsky-Fadin-Kuraev-Lipatov (BFKL) hard Pomeron, with a helicity flip of the proton. This “spin-dependent BFKL Pomeron” is required in a consistent expansion in powers of the momentum transfer t ≈−Δ$^{2}_{⊥}$ beyond first order. The spin-dependent Pomeron violates s-channel helicity conservation at O(Δ$^{2}_{⊥}$), and beyond. Expanding to leading twist only, it corresponds to generalized parton distributions E g (x,t) for vanishing skewness. We derive explicit expressions for the eikonal BFKL amplitudes, to all orders in dipole size times momentum transfer, for all helicity configurations of the particles in the initial and final states. We also provide numerical estimates of the helicity flip two gluon exchange amplitude at moderate x from a light cone quark model of the proton. The spin dependent BFKL Pomeron could, in principle, be discovered via double spin asymmetries in e+p → e+p+J/ψ with a transversely polarized proton and longitudinally polarized electron in the initial state.

Deep inelastic scattering↗
DOE OSTI2022

Jet tomography of hot and cold nuclear matter [Slides]

Jets are probes of microscopic structures of nuclear matter. With inclusive jets and hadrons, the transport approach is used to determine the QGP jet transport parameter. Much more information contained in k T -dependent observables, require to go beyond qˆ approximation and new tools. Test in-medium jet theory with existing eA data and future EIC.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗