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Articles 61 - 90 of 258

Full-Text Articles in Elementary Particles and Fields and String Theory

Inverse Moment Of The B Meson Quasidistribution Amplitude, Ji Xu, Xi-Ruo Zhang, Shuai Zhao Jan 2022

Inverse Moment Of The B Meson Quasidistribution Amplitude, Ji Xu, Xi-Ruo Zhang, Shuai Zhao

Physics Faculty Publications

We perform a study on the structure of the inverse moment (IM) of quasidistributions, by taking B-meson quasidistribution amplitude (quasi-DA) as an example. Based on a one-loop calculation, we derive the renormalization group equation and velocity evolution equation for the first IM of quasi-DA. We find that, in the large velocity limit, the first IM of B-meson quasi-DA can be factorized into IM as well as logarithmic moments of light-cone distribution amplitude (LCDA), accompanied by short distance coefficients. Our results can be useful either in understanding the patterns of perturbative matching in large momentum effective theory or evaluating inverse …


Toward The Determination Of The Gluon Helicity Distribution In The Nucleon From Lattice Quantum Chromodynamics, Colin Egerer, Bálint Joó, Joseph Karpie, Nikhil Karthik, Tanjib Khan, Christopher J. Monahan, Wayne Morris, Kostas Orginos, Anatoly Radyushkin, David G. Richards, Eloy Romero, Raza Sabbir Sufian, Savvas Zafeiropoulos Jan 2022

Toward The Determination Of The Gluon Helicity Distribution In The Nucleon From Lattice Quantum Chromodynamics, Colin Egerer, Bálint Joó, Joseph Karpie, Nikhil Karthik, Tanjib Khan, Christopher J. Monahan, Wayne Morris, Kostas Orginos, Anatoly Radyushkin, David G. Richards, Eloy Romero, Raza Sabbir Sufian, Savvas Zafeiropoulos

Physics Faculty Publications

We present the first exploratory lattice quantum chromodynamics (QCD) calculation of the polarized gluon Ioffe-time pseudodistribution in the nucleon. The Ioffe-time pseudodistribution provides a frame-independent and gauge-invariant framework to determine the gluon helicity in the nucleon from first principles. We employ a high-statistics computation using a 323 × 64 lattice ensemble characterized by a 358 MeV pion mass and a 0.094 fm lattice spacing. We establish the pseudodistribution approach as a feasible method to address the proton spin puzzle with successive improvements in statistical and systematic uncertainties anticipated in the future. Within the statistical precision of our data, we …


Beam-Recoil Transferred Polarization In K+Y Electroproduction In The Nucleon Resonance Region With Clas12, D. S. Carman, A. D'Angelo, L. Lanza, V. I. Mokeev, K. P. Adhikari, M. J. Amaryan, W. R. Armstrong, H. Atac, H. Avakian, C. Ayerbe Gayoso, N. A. Baltzell, L. Barion, M. Battaglieri, I. Bedlinskiy, B. Benkel, A. Bianconi, A. S. Biselli, M. Bondi, S. Boiarinov, V. Ziegler Jan 2022

Beam-Recoil Transferred Polarization In K+Y Electroproduction In The Nucleon Resonance Region With Clas12, D. S. Carman, A. D'Angelo, L. Lanza, V. I. Mokeev, K. P. Adhikari, M. J. Amaryan, W. R. Armstrong, H. Atac, H. Avakian, C. Ayerbe Gayoso, N. A. Baltzell, L. Barion, M. Battaglieri, I. Bedlinskiy, B. Benkel, A. Bianconi, A. S. Biselli, M. Bondi, S. Boiarinov, V. Ziegler

Physics Faculty Publications

Beam-recoil transferred polarizations for the exclusive electroproduction of K + Λ and K + Σ0 final states from an unpolarized proton target have been measured using the CLAS12 spectrometer at Jefferson Laboratory. The measurements at beam energies of 6.535 and 7.546 GeV span the range of four-momentum transfer Q2 from 0.3 to 4.5 GeV2 and invariant energy W from 1.6 to 2.4 GeV, while covering the full center-of-mass angular range of the K+. These new data extend the existing hyperon polarization data from CLAS in a similar kinematic range but from a significantly larger dataset. …


Neutron Spectroscopy Of The Parity-Violating 0.734 Ev Neutron Resonance In Lanthanum-139 In Preparation For The Noptrex Time Reversal Violation Experiment, Danielle Schaper Jan 2022

Neutron Spectroscopy Of The Parity-Violating 0.734 Ev Neutron Resonance In Lanthanum-139 In Preparation For The Noptrex Time Reversal Violation Experiment, Danielle Schaper

Theses and Dissertations--Physics and Astronomy

One of the most outstanding questions in physics is the matter-antimatter asymmetry of the Universe, resulting from excess baryogenesis processes during the early moments of the formation of the Universe. At present, the types of processes needed to explain this matter excess, so-called `CP-violating processes' are known to exist within the present framework of the Standard Model of particle physics. However, decades of research has shown that our understanding of the origin of these processes is incomplete, as we do not presently know of enough sources of CP-violating processes to account for the large baryon asymmetry that we observe. The …


Thermalization And Quantum Information In Conformal Field Theory, Ashish Kakkar Jan 2022

Thermalization And Quantum Information In Conformal Field Theory, Ashish Kakkar

Theses and Dissertations--Physics and Astronomy

The consequences of the constraints of conformal symmetry are far-reaching within
theoretical physics. In this dissertation we address a series of questions in conformal
field theory: 1) We calculate the spectrum of qKdV charges in a large central charge
expansion. 2) We determine the corrections to bulk information geometry from 1/N
contributions to holographic correlators. 3) We study the higher genus partitions
functions of CFTs associated with classical and quantum error-correcting codes.


Extractable Entanglement From A Euclidean Hourglass, Takanori Anegawa, Norihiro Iizuka, Daniel Kabat Jan 2022

Extractable Entanglement From A Euclidean Hourglass, Takanori Anegawa, Norihiro Iizuka, Daniel Kabat

Publications and Research

We previously proposed that entanglement across a planar surface can be obtained from the partition function on a Euclidean hourglass geometry. Here we extend the prescription to spherical entangling surfaces in conformal field theory. We use the prescription to evaluate log terms in the entropy of a conformal field theory in two dimensions, a conformally coupled scalar in four dimensions, and a Maxwell field in four dimensions. For Maxwell we reproduce the extractable entropy obtained by Soni and Trivedi. We take this as evidence that the hourglass prescription provides a Euclidean technique for evaluating extractable entropy in quantum field theory.


Two-Loop Four-Fermion Scattering Amplitude In Qed, R. Bonciani, A. Broggio, S. Di Vita, A. Ferroglia, M. K. Mandal, P. Mastrolia, L. Mattiazzi, A. Primo, J. Ronca, U. Schubert, W. J. Torres Bobadilla, F. Tramontano Jan 2022

Two-Loop Four-Fermion Scattering Amplitude In Qed, R. Bonciani, A. Broggio, S. Di Vita, A. Ferroglia, M. K. Mandal, P. Mastrolia, L. Mattiazzi, A. Primo, J. Ronca, U. Schubert, W. J. Torres Bobadilla, F. Tramontano

Publications and Research

We present the first fully analytic evaluation of the transition amplitude for the scattering of a massless into a massive pair of fermions at the two-loop level in quantum electrodynamics. Our result is an essential ingredient for the determination of the electromagnetic coupling within scattering reactions, beyond the currently known accuracy, which has a crucial impact on the evaluation of the anomalous magnetic moment of the muon. It will allow, in particular, for a precise determination of the leading hadronic contribution to the (g − 2)μ in the MUonE experiment at CERN, and therefore can be used to …


Model Of Electromagnetic Waves In An Axion-Induced Parity Symmetry Violation, Sarah Lipstone May 2021

Model Of Electromagnetic Waves In An Axion-Induced Parity Symmetry Violation, Sarah Lipstone

Macalester Journal of Physics and Astronomy

Axion particles have been postulated to resolve the strong CP problem in Quantum chromodynamics. The axion field may double as the inflaton field that produces cosmic inflation. In this project, we use a combination of analytical and numerical analysis to study how axion-induced parity symmetry violation affects the dynamics of electromagnetic waves.


Curved Spacetime In The Causal Set Approach To Quantum Gravity, Ayush Dhital May 2021

Curved Spacetime In The Causal Set Approach To Quantum Gravity, Ayush Dhital

Honors Theses

Causal Set theory is an approach to quantum gravity. In this approach, the spacetime continuum is assumed to be discrete rather than continuous. The discrete points in a causal set can be seen as a continuum spacetime if they can be embedded in a manifold such that the causal structure is preserved. In this regard, a manifold can be constructed by embedding a causal set preserving causal information between the neighboring points. In this thesis, some of the fundamental properties of causal sets are discussed and the curvature and dimension information of Minkowski, de Sitter, and Anti-de Sitter spaces is …


Exploring Manifoldlike Causal Sets And Their Dimensions, Santosh Bhandari Apr 2021

Exploring Manifoldlike Causal Sets And Their Dimensions, Santosh Bhandari

Honors Theses

Causal Set Theory is an approach to quantum gravity that tries to replace the continuum spacetime structure of general relativity with the spacetime that has the property of discreteness and causality. From the standpoint of causal set theory, our spacetime is made up of discrete points that are causally related to one another. A causal set is said to be manifoldlike if it can be faithfully embedded in a Lorentzian manifold. In this thesis, some of the fundamental properties of causal sets are discussed. The first chapter is devoted to the historical background of quantum gravity with a discussion of …


Exploring Qcd Factorization At Moderate Energy Scales, Eric Alan Moffat Apr 2021

Exploring Qcd Factorization At Moderate Energy Scales, Eric Alan Moffat

Physics Theses & Dissertations

Asymptotic freedom in QCD facilitates the use of partonic degrees of freedom over short distances, but physical processes are sensitive to a wide range of scales. Thus, it is necessary in QCD calculations to utilize a factorization scheme to separate a process into perturbative and non-perturbative factors. This separation relies on an assumption that one energy scale is infinitely larger than the other scales involved in the process. However, much experimental research in areas such as nucleon structure and quark-hadron duality occur at more moderate energy scales where that basic assumption may not be true but perturbative calculations should still …


Lorentz Violation In Neutrino Interactions, Pranav Jayaram Seetharaman Mar 2021

Lorentz Violation In Neutrino Interactions, Pranav Jayaram Seetharaman

Physics

Both the Standard Model of particle physics and General Relativity require Lorentz symmetry as a fundamental building block. In this paper, we learn about a framework called the Standard Model Extension that allows us to determine how physical phenomenon would change if we deviated from Lorentz invariance in the Standard Model and General Relativity. We use the Standard Model Extension to analyze a specific high-energy, astrophysical neutrino interaction that is only possible if Lorentz symmetry can be broken. The interaction we look at is the decay of a neutrino into an electron-positron pair, which is not possible in conventional physics. …


Extracting The Number Of Short Range Correlated Nucleon Pairs From Inclusive Electron Scattering Data, R. Weiss, A. W. Denniston, J. R. Pybus, O. Hen, E. Piasetzky, A. Schmidt, L. B. Weinstein, N. Barnea Mar 2021

Extracting The Number Of Short Range Correlated Nucleon Pairs From Inclusive Electron Scattering Data, R. Weiss, A. W. Denniston, J. R. Pybus, O. Hen, E. Piasetzky, A. Schmidt, L. B. Weinstein, N. Barnea

Physics Faculty Publications

The extraction of the relative abundances of short-range correlated (SRC) nucleon pairs from inclusive electron scattering is studied using the generalized contact formalism (GCF) with several nuclear interaction models. GCF calculations can reproduce the observed scaling of the cross-section ratios for nuclei relative to deuterium at high xB and large Q2, a2 = (σA/A)/(σd/2). In the nonrelativistic instant-form formulation, the calculation is very sensitive to the model parameters and only reproduces the data using parameters that are inconsistent with ab initio many-body calculations. Using a light-cone GCF formulation significantly decreases this sensitivity …


Role Of Boundary Conditions In Quantum Computations Of Scattering Observables, Raúl A. Briceño, Juan V. Guerrero, Maxwell T. Hansen, Alexandru M. Sturzu Jan 2021

Role Of Boundary Conditions In Quantum Computations Of Scattering Observables, Raúl A. Briceño, Juan V. Guerrero, Maxwell T. Hansen, Alexandru M. Sturzu

Physics Faculty Publications

Quantum computing may offer the opportunity to simulate strongly interacting field theories, such as quantum chromodynamics, with physical time evolution. This would give access to Minkowski-signature correlators, in contrast to the Euclidean calculations routinely performed at present. However, as with present-day calculations, quantum computation strategies still require the restriction to a finite system size, including a finite, usually periodic, spatial volume. In this work, we investigate the consequences of this in the extraction of hadronic and Compton-like scattering amplitudes. Using the framework presented in Briceno et al. [Phys. Rev. D 101, 014509 (2020)], we estimate the volume effects for various …


Gauge-Invariant Tmd Factorization For Drell-Yan Hadronic Tensor At Small X, Ian Balitsky Jan 2021

Gauge-Invariant Tmd Factorization For Drell-Yan Hadronic Tensor At Small X, Ian Balitsky

Physics Faculty Publications

The Drell-Yan hadronic tensor for electromagnetic (EM) current is calculated in the Sudakov region s ≫ Q2 ≫q2 with 1Q² accuracy, first at the tree level and then with the double-log accuracy. It is demonstrated that in the leading order in Nc the higher-twist quark-quark-gluon TMDs reduce to leading-twist TMDs due to QCD equation of motion. The resulting tensor for unpolarized hadrons is EM gauge-invariant and depends on two leading-twist TMDs: f1 responsible for total DY cross section, and Boer-Mulders function h1. The order-of-magnitude estimates of angular distributions for DY …


Experimental Tests Of Qcd Scaling Laws At Large Momentum Transfer In Exclusive Light-Meson Photoproduction, Moskov J. Amaryan, William J. Briscoe, Michael G. Ryskin, Igor I. Strakovsky Jan 2021

Experimental Tests Of Qcd Scaling Laws At Large Momentum Transfer In Exclusive Light-Meson Photoproduction, Moskov J. Amaryan, William J. Briscoe, Michael G. Ryskin, Igor I. Strakovsky

Physics Faculty Publications

We evaluated CLAS Collaboration measurements for the 90 meson photoproduction off the nucleon using a tagged photon beam spanning the energy interval s = 3–11 GeV2. The results are compared with the “quark counting rules” predictions.


Energy-Dependent Π⁺Π⁺Π⁺ Scattering Amplitude From Qcd, Maxwell T. Hansen, Raúl A. Briceño, Robert G. Edwards, Christopher E. Thomas, David J. Wilson Jan 2021

Energy-Dependent Π⁺Π⁺Π⁺ Scattering Amplitude From Qcd, Maxwell T. Hansen, Raúl A. Briceño, Robert G. Edwards, Christopher E. Thomas, David J. Wilson

Physics Faculty Publications

Focusing on three-pion states with maximal isospin π⁺π⁺π⁺, we present the first nonperturbative determination of an energy-dependent three-hadron scattering amplitude from first-principles QCD. The calculation combines finite-volume three-hadron energies, extracted using numerical lattice QCD, with a relativistic finite-volume formalism, required to interpret the results. To fully implement the latter, we also solve integral equations that relate an intermediate three-body K matrix to the physical three-hadron scattering amplitude. The resulting amplitude shows rich analytic structure and a complicated dependence on the two-pion invariant masses, represented here via Dalitz-like plots of the scattering rate.


Ruling Out Color Transparency In Quasielastic ¹²C(E,E'P) Up To Q² Of 14.2 (Gev/C)², D. Bhetuwal, J. Matter, H. Szumila-Vance, F. Hauenstein, C. Yero, J. Zhang, Et Al., Hall C. Collaboration Jan 2021

Ruling Out Color Transparency In Quasielastic ¹²C(E,E'P) Up To Q² Of 14.2 (Gev/C)², D. Bhetuwal, J. Matter, H. Szumila-Vance, F. Hauenstein, C. Yero, J. Zhang, Et Al., Hall C. Collaboration

Physics Faculty Publications

Quasielastic 12C(e,e'p) scattering was measured at spacelike 4-momentum transfer squared Q2 = 8, 9.4, 11.4, and 14.2 (GeV/c)2, the highest ever achieved to date. Nuclear transparency for this reaction was extracted by comparing the measured yield to that expected from a plane-wave impulse approximation calculation without any final state interactions. The measured transparency was consistent with no Q2 dependence, up to proton momenta of 8.5 GeV/c, ruling out the quantum chromodynamics effect of color transparency at the measured Q2 scales in exclusive (e, e'p) reactions. These results impose strict constraints on models of color …


Neural-Network Analysis Of Parton Distribution Functions From Ioffe-Time Pseudodistributions, Luigi Del Debbio, Tommaso Giani, Joseph Karpie, Kostas Orginos, Anatoly Radyushkin, Savvas Zafeiropoulos Jan 2021

Neural-Network Analysis Of Parton Distribution Functions From Ioffe-Time Pseudodistributions, Luigi Del Debbio, Tommaso Giani, Joseph Karpie, Kostas Orginos, Anatoly Radyushkin, Savvas Zafeiropoulos

Physics Faculty Publications

We extract two nonsinglet nucleon Parton Distribution Functions from lattice QCD data for reduced Ioffe-time pseudodistributions. We perform such analysis within the NNPDF framework, considering data coming from different lattice ensembles and discussing in detail the treatment of the different source of systematics involved in the fit. We introduce a recipe for taking care of systematics and use it to perform our extraction of light-cone PDFs.


Differential Cross Sections For Λ (1520) Using Photoproduction At Clas, K. P. Adhikari, M.J. Amaryan, G. Gavalian, M. Hattawy, Y. Prok, Et. Al., The Clas Collaboration Jan 2021

Differential Cross Sections For Λ (1520) Using Photoproduction At Clas, K. P. Adhikari, M.J. Amaryan, G. Gavalian, M. Hattawy, Y. Prok, Et. Al., The Clas Collaboration

Physics Faculty Publications

The reaction 𝛾p → K+Λ (1520) using photoproduction data from the CLAS g12 experiment at Jefferson Lab is studied. The decay of Λ(1520) into two exclusive channels, Σπ+π- and Σ-π+, is studied from the detected K+, π+, and π- particles. A good agreement is established for the Λ(1520) differential cross sections with the previous CLAS measurements. The differential cross sections as a function of center-of-mass angle are extended to higher photon energies. Newly added are the differential cross sections as a function of invariant four-momentum transfer t, …


Photoproduction Of The F₂(1270) Meson Using The Clas Detector, Krishna P. Adhikari, Moskov J. Amaryan, Dilini Bulumulla, Mohammad Hattawy, G. Gavalian, Charles E. Hyde, Yelena Prok, J. Zhang, Et Al., Clas Collaboration Jan 2021

Photoproduction Of The F₂(1270) Meson Using The Clas Detector, Krishna P. Adhikari, Moskov J. Amaryan, Dilini Bulumulla, Mohammad Hattawy, G. Gavalian, Charles E. Hyde, Yelena Prok, J. Zhang, Et Al., Clas Collaboration

Physics Faculty Publications

The quark structure of the f2(1270) meson has, for many years, been assumed to be a pure quark-antiquark (qq⁻) resonance with quantum numbers JPC = 2++. Recently, it was proposed that the f2(1270) is a molecular state made from the attractive interaction of two 𝜌 mesons. Such a state would be expected to decay strongly to final states with charged pions due to the dominant decay 𝜌 → π+π-, whereas decay to two neutral pions would likely be suppressed. Here, we measure for the first time the reaction 𝛾p …


B-Meson Ioffe-Time Distribution Amplitude At Short Distances, Shuai Zhao, Anatoly V. Radyushkin Jan 2021

B-Meson Ioffe-Time Distribution Amplitude At Short Distances, Shuai Zhao, Anatoly V. Radyushkin

Physics Faculty Publications

We propose the approach for a lattice investigation of light cone distribution amplitudes (LCDA) of heavy-light mesons, such as the B meson, using the formalism of parton pseudodistributions. A basic ingredient of the approach is the study of short-distance behavior of the B-meson Ioffe-time distribution amplitude (ITDA), which is a generalization of the B-meson LCDA in coordinate space. We construct a reduced ITDA for the B meson, and derive the matching relation between the reduced ITDA and the LCDA. The reduced ITDA is ultraviolet finite, which guarantees that the continuum limit exists on the lattice.


Measurement Of The Ar(E, E' P) And Ti(E, E' P) Cross Sections In Jefferson Lab Hall A, L. Gu, D. Abrams, A.M. Ankowski, L. Jiang, B. Aljawrneh, S. Alsalmi, F. Hauenstein, C. Hyde, Et Al., The Jefferson Lab Hall A. Collaboration Jan 2021

Measurement Of The Ar(E, E' P) And Ti(E, E' P) Cross Sections In Jefferson Lab Hall A, L. Gu, D. Abrams, A.M. Ankowski, L. Jiang, B. Aljawrneh, S. Alsalmi, F. Hauenstein, C. Hyde, Et Al., The Jefferson Lab Hall A. Collaboration

Physics Faculty Publications

The E12-14-012 experiment, performed in Jefferson Lab Hall A, has collected exclusive electron-scattering data (e, e'p) in parallel kinematics using natural argon and natural titanium targets. Here we report the first results of the analysis of the data set corresponding to beam energy 2222 GeV, electron scattering angle 21.5 degrees, and proton emission angle -50°. The differential cross sections, measured with ≈ 4% uncertainty, have been studied as a function of missing energy and missing momentum, and compared to the results of Monte Carlo simulations, obtained from a model based on the distorted-wave impulse approximation.


Measurements Of Dihadron Correlations Relative To The Event Plane In Au Plus Au Collisions At √Snn= 200 Gev, H. Agakishiev, M. M. Aggarwal, Z. Ahammed, S. Bueltmann, I. Koralt, D. Plyku, Et Al., Star Collaboration Jan 2021

Measurements Of Dihadron Correlations Relative To The Event Plane In Au Plus Au Collisions At √Snn= 200 Gev, H. Agakishiev, M. M. Aggarwal, Z. Ahammed, S. Bueltmann, I. Koralt, D. Plyku, Et Al., Star Collaboration

Physics Faculty Publications

Dihadron azimuthal correlations containing a high transverse momentum (pT) trigger particle are sensitive to the properties of the nuclear medium created at RHIC through the strong interactions occurring between the traversing parton and the medium, i.e. jet-quenching. Previous measurements revealed a strong modification to dihadron azimuthal correlations in Au+Au collisions with respect to p+p and d+Au collisions. The modification increases with the collision centrality, suggesting a path-length or energy density dependence to the jet-quenching effect. This paper reports STAR measurements of dihadron azimuthal correlations in mid-central (20%-60%) Au+Au collisions at √sNN = 200 GeV as a function …


On-Shell Representations Of Two-Body Transition Amplitudes: Single External Current, Raúl A. Briceño, Andrew W. Jackura, Felipe G. Ortega-Gama, Keegan H. Sherman Jan 2021

On-Shell Representations Of Two-Body Transition Amplitudes: Single External Current, Raúl A. Briceño, Andrew W. Jackura, Felipe G. Ortega-Gama, Keegan H. Sherman

Physics Faculty Publications

This work explores scattering amplitudes that couple two-particle systems via a single external current insertion, 2 + J → 2. Such amplitudes can provide structural information about the excited QCD spectrum. We derive an exact analytic representation for these reactions. From these amplitudes, we show how to rigorously define resonance and bound-state form factors. Furthermore, we explore the consequences of the narrow-width limit of the amplitudes as well as the role of the Ward-Takahashi identity for conserved vector currents. These results hold for any number of two-body channels with no intrinsic spin, and a current with arbitrary Lorentz structure and …


Solving Relativistic Three-Body Integral Equations In The Presence Of Bound States, Andrew W. Jackura, Raúl A. Briceño, Sebastian M. Dawid, Md. Habib E. Islam, Connor Mccarty Jan 2021

Solving Relativistic Three-Body Integral Equations In The Presence Of Bound States, Andrew W. Jackura, Raúl A. Briceño, Sebastian M. Dawid, Md. Habib E. Islam, Connor Mccarty

Physics Faculty Publications

We present a simple scheme for solving relativistic integral equations for the partial-wave projected three-body amplitudes. Our techniques are used to solve a problem of three scalar particles with a formation of a S-wave two-body bound state. We rewrite the problem in a form suitable for numerical solution and then explore three solving strategies. In particular, we discuss different ways of incorporating the bound-state pole contribution in the integral equations. All of them lead to agreement with previous results obtained using finite-volume spectra of the same theory, providing further evidence of the validity of the existing finite- and infinite-volume formalism …


Consistency Checks For Two-Body Finite-Volume Matrix Elements: Conserved Currents And Bound States, Raúl A. Briceño, Christopher J. Monahan Jan 2021

Consistency Checks For Two-Body Finite-Volume Matrix Elements: Conserved Currents And Bound States, Raúl A. Briceño, Christopher J. Monahan

Physics Faculty Publications

We present a model-independent framework to determine finite-volume corrections of matrix elements of spatially separated current-current operators. We define these matrix elements in terms of Compton-like amplitudes, i.e., amplitudes coupling single-particle states via two current insertions. We show that the infrared behavior of these matrix elements is dominated by the single-particle pole, which is approximated by the elastic form factors of the lowest-lying hadron. Therefore, given lattice data on the relevant elastic form factors, the finite-volume effects can be estimated nonperturbatively and without recourse to effective field theories. For illustration purposes, we investigate the implications of the proposed formalism for …


Drell-Yan Angular Lepton Distributions At Small X From Tmd Factorization, Ian Balitsky Jan 2021

Drell-Yan Angular Lepton Distributions At Small X From Tmd Factorization, Ian Balitsky

Physics Faculty Publications

The Drell-Yan process is studied in the framework of TMD factorization in the Sudakov region s » Q2 » q2 corresponding to recent LHC experiments with Q2 of order of mass of Z-boson and transverse momentum of DY pair ∼ few tens GeV. The DY hadronic tensors are expressed in terms of quark and quark-gluon TMDs with 1Q2 and 1Nc2 accuracy. It is demonstrated that in the leading order in Nc the higher-twist quark-quark-gluon TMDs reduce to leading-twist TMDs due to QCD equation of motion. The resulting hadronic tensors depend on …


One-Loop Structure Of Parton Distribution For The Gluon Condensate And "Zero Modes", Anatoly Radyushkin, Shuai Zhao Jan 2021

One-Loop Structure Of Parton Distribution For The Gluon Condensate And "Zero Modes", Anatoly Radyushkin, Shuai Zhao

Physics Faculty Publications

We present results for one-loop corrections to the recently introduced “gluon condensate” PDF F(x). In particular, we give expression for the gg-part of its evolution kernel. To enforce strict compliance with the gauge invariance requirements, we have used on-shell states for external gluons, and have obtained identical results both in Feynman and light-cone gauges. No “zero mode” δ(x) terms were found for the twist-4 gluon PDF F(x). However a q2δ(x) term was found for the ξ = 0 GPD F(x, q2) at nonzero momentum transfer q. Overall, our results do not agree with the original attempt …


Towards High-Precision Parton Distributions From Lattice Qcd Via Distillation, Colin Egerer, Robert G. Edwards, Christos Kallidonis, Kostas Orginos, Anatoly V. Radyushkin, David G. Richards, Eloy Romero, Savvas Zafeiropoulos, On Behalf Of The Hadstruc Collaboration Jan 2021

Towards High-Precision Parton Distributions From Lattice Qcd Via Distillation, Colin Egerer, Robert G. Edwards, Christos Kallidonis, Kostas Orginos, Anatoly V. Radyushkin, David G. Richards, Eloy Romero, Savvas Zafeiropoulos, On Behalf Of The Hadstruc Collaboration

Physics Faculty Publications

We apply the Distillation spatial smearing program to the extraction of the unpolarized isovector valence PDF of the nucleon. The improved volume sampling and control of excited-states afforded by distillation leads to a dramatically improved determination of the requisite Ioffe-time Pseudo-distribution (pITD). The impact of higher-twist effects is subsequently explored by extending the Wilson line length present in our non-local operators to one half the spatial extent of the lattice ensemble considered. The valence PDF is extracted by analyzing both the matched Ioffe-time Distribution (ITD), as well as a direct matching of the pITD to the PDF. Through development of …