Open Access. Powered by Scholars. Published by Universities.®

Elementary Particles and Fields and String Theory Commons™

Open Access. Powered by Scholars. Published by Universities.®

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 631 - 660 of 1000

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

Relativistic, Model-Independent, Multichannel 2 → 2 Transition Amplitudes In A Finite Volume, Raúl A. Briceño, Maxwell T. Hansen Jan 2016

Relativistic, Model-Independent, Multichannel 2 → 2 Transition Amplitudes In A Finite Volume, Raúl A. Briceño, Maxwell T. Hansen

Physics Faculty Publications

We derive formalism for determining 2+𝓙 → 2 infinite-volume transition amplitudes from finite-volume matrix elements. Specifically, we present a relativistic, model-independent relation between finite-volume matrix elements of external currents and the physically observable infinite-volume matrix elements involving two-particle asymptotic states. The result presented holds for states composed of two scalar bosons. These can be identical or nonidentical and, in the latter case, can be either degenerate or nondegenerate. We further accommodate any number of strongly coupled two-scalar channels. This formalism will, for example, allow future lattice QCD calculations of the ρ-meson form factor, in which the unstable nature of …

Go to article

𝜋𝜋 → 𝜋𝛾* Amplitude And The Resonant 𝜌 → 𝜋𝛾* Transition From Lattice Qcd, Raúl A. Briceño, Jozef J. Dudek, Robert G. Edwards, Christian J. Shultz, Christopher E. Thomas, David J. Wilson Jan 2016

𝜋𝜋 → 𝜋𝛾* Amplitude And The Resonant 𝜌 → 𝜋𝛾* Transition From Lattice Qcd, Raúl A. Briceño, Jozef J. Dudek, Robert G. Edwards, Christian J. Shultz, Christopher E. Thomas, David J. Wilson

Physics Faculty Publications

We present a determination of the P-wave 𝜋𝜋 → 𝜋𝛾⋆ transition amplitude from lattice quantum chromodynamics. Matrix elements of the vector current in a finite volume are extracted from three-point correlation functions, and from these we determine the infinite-volume amplitude using a generalization of the Lellouch-Lüscher formalism. We determine the amplitude for a range of discrete values of the 𝜋𝜋 energy and virtuality of the photon and observe the expected dynamical enhancement due to the ρ resonance. Describing the energy dependence of the amplitude, we are able to analytically continue into the complex energy plane and from the residue …

Go to article

Heavy Quark Production At An Electron-Ion Collider, E. Chudakov, D. Higinbotham, C. Hyde, S. Furletov, Yu Furletova, D. Nguyen, M. Stratmann, M. Strickman, C. Weiss Jan 2016

Heavy Quark Production At An Electron-Ion Collider, E. Chudakov, D. Higinbotham, C. Hyde, S. Furletov, Yu Furletova, D. Nguyen, M. Stratmann, M. Strickman, C. Weiss

Physics Faculty Publications

An Electron-Ion Collider (EIC) with center-of-mass energies √seN ∼ 20-100 GeV and luminosity L ∼ 10³⁴ cm-² s-¹ would offer new opportunities to study heavy quark production in high-energy electron or photon scattering on protons and nuclei. We report about an R&D project exploring the feasibility of direct measurements of nuclear gluon densities at x >∼ 0.1 (gluonic EMC effect, antishadowing) using open charm production at EIC. We describe the charm production rates and angle-momentum distributions at large x and discuss methods of charm reconstruction using next-generation detector capabilities (π/K identification, vertex reconstruction). The results could be …

Go to article

Probing Nuclear Gluons With Heavy Flavors At An Electron-Ion Collider, E. Chudakov, D. Higinbotham, C. Hyde, S. Furletov, Y. Furletova, D. Nguyen, M. Stratmann, M. Strikman, C. Weiss, R. Yoshida Jan 2016

Probing Nuclear Gluons With Heavy Flavors At An Electron-Ion Collider, E. Chudakov, D. Higinbotham, C. Hyde, S. Furletov, Y. Furletova, D. Nguyen, M. Stratmann, M. Strikman, C. Weiss, R. Yoshida

Physics Faculty Publications

We explore the feasibility of direct measurements of nuclear gluon densities using heavy-quark production (open charm, beauty) at a future Electron-Ion Collider (EIC). We focus on the regions x> 0.3 (EMC effect) and x ~ 0.05-0.1 (antishadowing), where the nuclear modifications of the gluon density offer insight into non-nucleonic degrees of freedom and the QCD structure of nucleon-nucleon interactions. We describe the charm production rates and momentum distributions in nuclear deep-inelastic scattering (DIS) at Large XB, and comment on the possible methods for charm reconstruction using next-generation detectors at the EIC (π/K identification, tracking, vertex detection).

Go to article

Relating Transverse-Momentum-Dependent And Collinear Factorization Theorems In A Generalized Formalism, J. Collins, L. Gamberg, A. Prokudin, T. C. Rogers, N. Sato, B. Wang Jan 2016

Relating Transverse-Momentum-Dependent And Collinear Factorization Theorems In A Generalized Formalism, J. Collins, L. Gamberg, A. Prokudin, T. C. Rogers, N. Sato, B. Wang

Physics Faculty Publications

We construct an improved implementation for combining transverse-momentum-dependent (TMD) factorization and collinear factorization. TMD factorization is suitable for low transverse momentum physics, while collinear factorization is suitable for high transverse momenta and for a cross section integrated over transverse momentum. The result is a modified version of the standard 𝑊 + 𝑌 prescription traditionally used in the Collins-Soper-Sterman (CSS) formalism and related approaches. We further argue that questions regarding the shape and 𝑄 dependence of the cross sections at lower 𝑄 are largely governed by the matching to the 𝑌 term.

Go to article

Studies Of Light Nuclei In Χeft: A Status Report, R. Schiavilla Jan 2016

Studies Of Light Nuclei In Χeft: A Status Report, R. Schiavilla

Physics Faculty Publications

A status report on χEFT studies of few-nucleon electroweak structure and dynamics is provided, including electromagnetic form factors of few nucleon systems, the pp weak fusion and muon weak captures on deuteron and ³He, an a number of parity-violating processes induced by hadronic weak interactions

Go to article

Electron-Ion Collider: The Next Qcd Frontier, A. Accardi, J. L. Albacete, M. Anselmino, N. Armesto, E. C. Aschenauer, A. Bacchetta, D. Boer, W. K. Brooks, T. Burton, N.-B. Chang, C. E. Hyde Jan 2016

Electron-Ion Collider: The Next Qcd Frontier, A. Accardi, J. L. Albacete, M. Anselmino, N. Armesto, E. C. Aschenauer, A. Bacchetta, D. Boer, W. K. Brooks, T. Burton, N.-B. Chang, C. E. Hyde

Physics Faculty Publications

This White Paper presents the science case of an Electron-Ion Collider (EIC), focused on the structure and interactions of gluon-dominated matter, with the intent to articulate it to the broader nuclear science community. It was commissioned by the managements of Brookhaven National Laboratory (BNL) and Thomas Jefferson National Accelerator Facility (JLab) with the objective of presenting a summary of scientific opportunities and goals of the EIC as a follow-up to the 2007 NSAC Long Range plan. This document is a culmination of a community-wide effort in nuclear science following a series of workshops on EIC physics over the past decades …

Go to article

Issues And Opportunities In Exotic Hadrons, R.A. Briceño, T. D. Cohen, S. Coito, J. J. Dudek, E. Eichten, R. E. Mitchell Jan 2016

Issues And Opportunities In Exotic Hadrons, R.A. Briceño, T. D. Cohen, S. Coito, J. J. Dudek, E. Eichten, R. E. Mitchell

Physics Faculty Publications

The last few years have been witness to a proliferation of new results concerning heavy exotic hadrons. Experimentally, many new signals have been discovered that could be pointing towards the existence of tetraquarks, pentaquarks, and other exotic configurations of quarks and gluons. Theoretically, advances in lattice field theory techniques place us at the cusp of understanding complex coupled-channel phenomena, modelling grows more sophisticated, and effective field theories are being applied to an ever greater range of situations. It is thus an opportune time to evaluate the status of the field. In the following, a series of high priority experimental and …

Go to article

Laser Pulsing In Linear Compton Scattering, G. A. Krafft, E. Johnson, K. Deitrick, B. Terzić, R. Kelmar, T. Hodges, J. R. Delayen Jan 2016

Laser Pulsing In Linear Compton Scattering, G. A. Krafft, E. Johnson, K. Deitrick, B. Terzić, R. Kelmar, T. Hodges, J. R. Delayen

Physics Faculty Publications

Previous work on calculating energy spectra from Compton scattering events has either neglected considering the pulsed structure of the incident laser beam, or has calculated these effects in an approximate way subject to criticism. In this paper, this problem has been reconsidered within a linear plane wave model for the incident laser beam. By performing the proper Lorentz transformation of the Klein-Nishina scattering cross section, a spectrum calculation can be created which allows the electron beam energy spread and emittance effects on the spectrum to be accurately calculated, essentially by summing over the emission of each individual electron. Such an …

Go to article

Measurements Of Dⁿ² And Aⁿ¹: Probing The Neutron Spin Structure, D. Flay, M. Posik, D. S. Parno, K. Allada, M. Canan, C. Hyde, Jefferson Lab Hall A Collaboration Jan 2016

Measurements Of Dⁿ² And Aⁿ¹: Probing The Neutron Spin Structure, D. Flay, M. Posik, D. S. Parno, K. Allada, M. Canan, C. Hyde, Jefferson Lab Hall A Collaboration

Physics Faculty Publications

We report on the results of the E06-014 experiment performed at Jefferson Lab in Hall A, where a precision measurement of the twist-3 matrix element d2 of the neutron dⁿ2 was conducted. The quantity dⁿ2 represents the average color Lorentz force a struck quark experiences in a deep inelastic electron scattering event off a neutron due to its interaction with the hadronizing remnants. This color force was determined from a linear combination of the third moments of the 3He spin structure functions, g1 and g2, after nuclear corrections had been applied to these …

Go to article

Gluon Tmd In Particle Production From Low To Moderate X, I. Balitsky, A. Tarasov Jan 2016

Gluon Tmd In Particle Production From Low To Moderate X, I. Balitsky, A. Tarasov

Physics Faculty Publications

We study the rapidity evolution of gluon transverse momentum dependent distributions appearing in processes of particle production and show how this evolution changes from small to moderate Bjorken x.

Go to article

Iterative Monte Carlo Analysis Of Spin-Dependent Parton Distributions, Nobuo Sato, W. Melnitchouk, S. E. Kuhn, J. J. Ethier, A. Accardi, Jefferson Lab Angular Momentum Collaboration Jan 2016

Iterative Monte Carlo Analysis Of Spin-Dependent Parton Distributions, Nobuo Sato, W. Melnitchouk, S. E. Kuhn, J. J. Ethier, A. Accardi, Jefferson Lab Angular Momentum Collaboration

Physics Faculty Publications

We present a comprehensive new global QCD analysis of polarized inclusive deep-inelastic scattering, including the latest high-precision data on longitudinal and transverse polarization asymmetries from Jefferson Lab and elsewhere. The analysis is performed using a new iterative Monte Carlo fitting technique which generates stable fits to polarized parton distribution functions (PDFs) with statistically rigorous uncertainties. Inclusion of the Jefferson Lab data leads to a reduction in the PDF errors for the valence and sea quarks, as well as in the gluon polarization uncertainty at x ≳ 0.1 . The study also provides the first determination of the flavor-separated twist-3 PDFs …

Go to article

A Search For The Lhcb Charmed "Pentaquark" Using Photoproduction Of J/Ψ At Threshold In Hall C At Jefferson Lab, A. Asaturyan, H. Mkrtchyan, T. Tadevosyan, S. Zhamkochyan, J. Arrington, W. Armstrong, K. Hafidi, M. Hattawy, Z. Ye, K. Aniol, H. Gao, Z. Zhao, T. Liu, X. Yan, C. Gu, C. Peng, X. Li, W. Xiong, P. Markowitz, K. Adhikari, H. Bhatt, D. Bhetuwal, J. Dunne, D. Dutta, L. El-Fassi, L. Ye, F. R. Wesselmann, X. Chen, Q. Fu, R. Wang, Y. Zhang, F. Zhao, R. Dupré, G. M. Huber, W. Li, A. Zafar, S. Bae, H. Choi, S. Choi, H. Go, J. Ha, H. Atac, B. Duran, S. Joosten, Z.-E. Meziani, M. Paolone, M. Rehfuss, N. Sparveris, J.-P. Chen, E. Chudakov, M. Diefenthaler, O. Hansen, D. Higinbotham, M. Jones, D. Meekins, L. Pentchev, E. Pooser, S. Wood Jan 2016

A Search For The Lhcb Charmed "Pentaquark" Using Photoproduction Of J/Ψ At Threshold In Hall C At Jefferson Lab, A. Asaturyan, H. Mkrtchyan, T. Tadevosyan, S. Zhamkochyan, J. Arrington, W. Armstrong, K. Hafidi, M. Hattawy, Z. Ye, K. Aniol, H. Gao, Z. Zhao, T. Liu, X. Yan, C. Gu, C. Peng, X. Li, W. Xiong, P. Markowitz, K. Adhikari, H. Bhatt, D. Bhetuwal, J. Dunne, D. Dutta, L. El-Fassi, L. Ye, F. R. Wesselmann, X. Chen, Q. Fu, R. Wang, Y. Zhang, F. Zhao, R. Dupré, G. M. Huber, W. Li, A. Zafar, S. Bae, H. Choi, S. Choi, H. Go, J. Ha, H. Atac, B. Duran, S. Joosten, Z.-E. Meziani, M. Paolone, M. Rehfuss, N. Sparveris, J.-P. Chen, E. Chudakov, M. Diefenthaler, O. Hansen, D. Higinbotham, M. Jones, D. Meekins, L. Pentchev, E. Pooser, S. Wood

Physics Faculty Publications

We propose to measure the photo-production cross section of J/Ψ near threshold in search of the recently observed LHCb hidden charm resonances Pc(4380) and Pc(4450) consistent with "pentaquarks." The observation of these resonances in photo-production is important to differentiate the true resonance nature of the LHCb states from kinematics enhancements. The bremsstrahlung photon beam produced with an 11 GeV electron beam at CEBAF enables us to cover the energy range of J/Ψ production from the threshold photo-production energy of 8.2 GeV to an energy beyond the presumed Pc(4450) resonance production. The proposed experiment will be carried out in Hall C …

Go to article

Lattice Qcd Calculation Of The Momentum Fraction Carried By Quarks In The Nucleon, And The Roper Puzzle, Mingyang Sun Jan 2016

Lattice Qcd Calculation Of The Momentum Fraction Carried By Quarks In The Nucleon, And The Roper Puzzle, Mingyang Sun

Theses and Dissertations--Physics and Astronomy

This thesis is concerned with the lattice QCD calculation of the momentum fraction carried by quarks in the nucleon. Particularly, the strange quark contribution, (x)s, is calculated, as well as the ratio of the strange (x) to that of u/d in the disconnected insertion which will be useful in constraining the global fit of parton distribution functions at small x. The disconnected insertion is known to be hard to calculate on the lattice. We adopt the overlap fermion action on several 2 + 1 flavor domain-wall fermion ensembles with a light sea quark mass which corresponds to pion …

Go to article

Boundary Conditions As Dynamical Fields, V. Parameswaran Nair, Dimitra Karabali Dec 2015

Boundary Conditions As Dynamical Fields, V. Parameswaran Nair, Dimitra Karabali

Publications and Research

The possibility of treating boundary conditions in terms of a bilocal dynamical field is formalized in terms of a boundary action. This allows for a simple path-integral perturbation theory approach to physical effects such as radiation from a time-dependent boundary. The nature of the action which governs the dynamics of the bilocal field is investigated for a limited case (which includes the Robin boundary conditions).

Go to article

D-Brane Instantons As Gauge Instantons In Orientifolds Of Chiral Quiver Theories, Sebastian Franco, Ander Retolaza, Angel Uranga Nov 2015

D-Brane Instantons As Gauge Instantons In Orientifolds Of Chiral Quiver Theories, Sebastian Franco, Ander Retolaza, Angel Uranga

Publications and Research

Systems of D3-branes at orientifold singularities can receive non-perturbative D-brane instanton corrections, inducing field theory operators in the 4d effective theory. In certain non-chiral examples, these systems have been realized as the infrared end point of a Seiberg duality cascade, in which the D-brane instanton effects arise from strong gauge theory dynamics. We present the rst UV duality cascade completion of chiral D3-brane theories, in which the D-brane instantons arise from gauge theory dynamics. Chiral examples are interesting because the instanton fermion zero mode sector is topologically protected, and therefore lead to more robust setups. As an application of our …

Go to article

Do All Bps Black Hole Microstates Carry Zero Angular Momentum?, Abishek Chowdhury, Richard S. Garavuso, Swapnamay Mondal, Ashoke Sen Nov 2015

Do All Bps Black Hole Microstates Carry Zero Angular Momentum?, Abishek Chowdhury, Richard S. Garavuso, Swapnamay Mondal, Ashoke Sen

Publications and Research

From the analysis of the near horizon geometry and supersymmetry algebra it has been argued that all the microstates of single centered BPS black holes with four unbroken supersymmetries carry zero angular momentum in the region of the moduli space where the black hole description is valid. A stronger form of the conjecture would be that the result holds for any sufficiently generic point in the moduli space. In this paper we set out to test this conjecture for a class of black hole microstates in type II string theory on T6 , represented by four stacks of D-branes wrapped …

Go to article

2d (0,2) Quiver Gauge Theories And D-Branes, Sebastian Franco, Dongwook Ghim, Sangmin Lee, Rak-Kyeong Seong, Daisuke Yokoyama Sep 2015

2d (0,2) Quiver Gauge Theories And D-Branes, Sebastian Franco, Dongwook Ghim, Sangmin Lee, Rak-Kyeong Seong, Daisuke Yokoyama

Publications and Research

We initiate a systematic study of 2d(0,2) quiver gauge theories on the world-volume of D1-branes probing singular toric Calabi-Yau 4-folds. We present an algorithm for efficiently calculating the classical mesonic moduli spaces of these theories, which cor-respond to the probed geometries. We also introduce a systematic procedure for constructing the gauge theories for arbitrary toric singularities by means of partial resolution, which translates to higgsing in the field theory. Finally, we introduce Brane Brick Models, a novel class of brane configurations that consist of D4-branes suspended from an NS5-brane wrap-ping a holomorphic surface, tessellating a 3-torus. Brane Brick Models are …

Go to article

Electron Vortices In Photoionization By Circularly Polarized Attosecond Pulses, Jean Marcel Ngoko Djiokap, S. X. Hu, L. B. Madsen, N. L. Manakov, A. V. Meremianin, Anthony F. Starace Sep 2015

Electron Vortices In Photoionization By Circularly Polarized Attosecond Pulses, Jean Marcel Ngoko Djiokap, S. X. Hu, L. B. Madsen, N. L. Manakov, A. V. Meremianin, Anthony F. Starace

Anthony F. Starace Publications

Single ionization of He by two oppositely circularly polarized, time-delayed attosecond pulses is shown to produce photoelectron momentum distributions in the polarization plane having helical vortex structures sensitive to the time delay between the pulses, their relative phase, and their handedness. Results are obtained by both ab initio numerical solution of the two-electron time-dependent Schrödinger equation and by a lowest-order perturbation theory analysis. The energy, bandwidth, and temporal duration of attosecond pulses are ideal for observing these vortex patterns.

Go to article

Favorable Target Positions For Intense Laser Acceleration Of Electrons In Hydrogen-Like, Highly-Charged Ions, Liang-Wen Pi, S. X. Hu, Anthony F. Starace Aug 2015

Favorable Target Positions For Intense Laser Acceleration Of Electrons In Hydrogen-Like, Highly-Charged Ions, Liang-Wen Pi, S. X. Hu, Anthony F. Starace

Anthony F. Starace Publications

Classical relativistic Monte Carlo simulations of petawatt laser acceleration of electrons bound initially in hydrogen-like, highly-charged ions show that both the angles and energies of the laser-accelerated electrons depend on the initial ion positions with respect to the laser focus. Electrons bound in ions located after the laser focus generally acquire higher (≈GeV) energies and are ejected at smaller angles with respect to the laser beam. Our simulations assume a tightly-focused linearly-polarized laser pulse with intensity approaching 1022W/cm2. Up to fifth order corrections to the paraxial approximation of the laser field in the focal region are …

Go to article

Scaling Laws For High-Order-Harmonic Generation With Midinfrared Laser Pulses, M. V. Frolov, N. L. Manakov, Wei-Hao Xiong, Liang-You Peng, J. Burgdörfer, Anthony F. Starace Aug 2015

Scaling Laws For High-Order-Harmonic Generation With Midinfrared Laser Pulses, M. V. Frolov, N. L. Manakov, Wei-Hao Xiong, Liang-You Peng, J. Burgdörfer, Anthony F. Starace

Anthony F. Starace Publications

We derive an analytic expression for thewavelength scaling of the high-order-harmonic generation (HHG) yield induced by midinfrared driving laser fields. It is based on a quasiclassical description of the returning electron wave packet, which is shown to be largely independent of atomic properties. The accuracy of this analytic expression is confirmed by comparison with results of numerical solutions of the time-dependent Schr¨odinger equation for wavelengths in the range of 1.4 μm ≤ λ ≤ 4 μm. We verify the wavelength scaling of the HHG yield found numerically for midinfrared laser fields in a recent paper by Le et al. [

Go to article

Photodetachment Of A Model Molecular System By An Elliptically Polarized Field, M. V. Frolov, N. L. Manakov, S. S. Marmo, Anthony F. Starace Jul 2015

Photodetachment Of A Model Molecular System By An Elliptically Polarized Field, M. V. Frolov, N. L. Manakov, S. S. Marmo, Anthony F. Starace

Anthony F. Starace Publications

The differential cross section for one-photon molecular detachment by an elliptically polarized field is analyzed for a one-electron molecular model comprised of an electron in the field of two (generally nonequivalent) attractive zero-range potentials (ZRPs) separated by the distance R. A phenomenological parametrization of the photodetachment cross section for a fixed-in-space molecular system in terms of two scalar dynamical parameters is presented and circular dichroism effects are discussed. Analytic results for the dynamical molecular parameters within the ZRP molecular model are used to analyze interference phenomena (including two-center interference) and dichroic effects in the detached electron angular distributions and …

Go to article

Singly-Spinning Black Rings Ind= 5 U(1)3 Supergravity, H. Lu, C. N. Pope, Justin F. Vázquez-Poritz, Zhibai Zhang Jun 2015

Singly-Spinning Black Rings Ind= 5 U(1)3 Supergravity, H. Lu, C. N. Pope, Justin F. Vázquez-Poritz, Zhibai Zhang

Publications and Research

We construct black ring solutions in five-dimensional U(1)3supergravity which carry three dipole charges, three electric charges and one angular momentum parameter.These solutions are written in a form that is sufficiently compact that their global and thermodynamic properties can be studied explicitly. In particular, we find that the Smarrformula is obeyed regardless of whether or not conical singularities are present, where as the first law of thermodynamics holds only in the absence of conical singularities. We also present black ring solutions with three background magnetic fields.

Go to article

Cuore Image Analysis And Cuore-0 Shifting: A Contribution To The Search For Neutrinoless Double Beta Decay, Dakota Christopher Rose Jun 2015

Cuore Image Analysis And Cuore-0 Shifting: A Contribution To The Search For Neutrinoless Double Beta Decay, Dakota Christopher Rose

Physics

In an effort to aid in the work of the Cryogenic Underground Observatory of Rare Events (CUORE) in moving towards confirming the existence of Neutrinoless Double Beta Decay, a six week trip was made to Assergi, Italy to work as an Onsite Shifter for the previous generation of the experiment, CUORE-0, as well as to aid in construction of the full CUORE detector. Furthermore, to help in understanding possible sources of experimental error, work was done analyzing images taken of the glue spots on the faces of each Tellurium Oxide detector crystals (also containing the source of the decay, Tellurium-130). …

Go to article

Analysis Of The Energy Spectrum Of Michel Electrons In Microboone, Philip Griffith Kellogg Apr 2015

Analysis Of The Energy Spectrum Of Michel Electrons In Microboone, Philip Griffith Kellogg

Undergraduate Honors Thesis Projects

The MicroBooNE experiment at Fermilab was designed both to investigate results from anomalies seen in short-baseline experiments and to prototype technology for larger scale experiments. MicroBooNE hopes to investigate an excess of low-energy events seen in a preceding experiment, using improved detector resolution. The goal of this thesis was to perform a calibration of the MicroBooNE detector by determining the Michel electron energy spectrum inside the detector. Michel electrons result from the decay of muons, and have a very well understood energy spectrum. Muons from cosmic rays continually pass through the detector, roughly 1% of which will decay within the …

Go to article

Meson Photo-Couplings From Lattice Quantum Chromodynamics, Christian J. P. Shultz Apr 2015

Meson Photo-Couplings From Lattice Quantum Chromodynamics, Christian J. P. Shultz

Physics Theses & Dissertations

We explore the calculation of three-point functions featuring a vector current insertion in lattice Quantum Chromodynamics. These three-point functions, in general, contain information about many radiative transition matrix elements simultaneously. We develop and implement the technology necessary to isolate a single matrix element via the use of optimized operators, operators designed to interpolate a single meson eigenstate, which are constructed as variationally optimized linear combination of meson interpolating fields within a large basis. In order to frame the results we also explore some well known phenomenology arising within the context of the constituent quark model before transitioning to a lattice …

Go to article

Rescattering Effects In Laser-Assisted Electron-Atom Bremsstrahlung, A. N. Zheltukhin, A. V. Flegel, M. V. Frolov, N. L. Manakov, Anthony F. Starace Mar 2015

Rescattering Effects In Laser-Assisted Electron-Atom Bremsstrahlung, A. N. Zheltukhin, A. V. Flegel, M. V. Frolov, N. L. Manakov, Anthony F. Starace

Anthony F. Starace Publications

Rescattering effects in non-resonant spontaneous laser-assisted electron–atom bremsstrahlung (LABrS) are analyzed within the framework of time-dependent effective-range (TDER) theory. It is shown that high energy LABrS spectra exhibit rescattering plateau structures that are similar to those that are well-known in strong field laser-induced processes as well as those that have been predicted theoretically in laser-assisted collision processes. In the limit of a low-frequency laser field, an analytic description of LABrS is obtained from a rigorous quantum analysis of the exact TDER results for the LABrS amplitude. This amplitude is represented as a sum of factorized terms involving three factors, each …

Go to article

Geometrization Conditions For Perfect Fluids, Scalar Fields, And Electromagnetic Fields, Charles G. Torre, Dionisios Krongos Mar 2015

Geometrization Conditions For Perfect Fluids, Scalar Fields, And Electromagnetic Fields, Charles G. Torre, Dionisios Krongos

Presentations and Publications

Rainich-type conditions giving a spacetime “geometrization” of matter fields in general relativity are reviewed and extended. Three types of matter are considered: perfect fluids, scalar fields, and elec- tromagnetic fields. Necessary and sufficient conditions on a spacetime metric for it to be part of a perfect fluid solution of the Einstein equa- tions are given. Formulas for constructing the fluid from the metric are obtained. All fluid results hold for any spacetime dimension. Ge- ometric conditions on a metric which are necessary and sufficient for it to define a solution of the Einstein-scalar field equations and for- mulas for constructing …

Go to article

Variation Of The Linear Biconformal Action, James Thomas Wheeler Jan 2015

Variation Of The Linear Biconformal Action, James Thomas Wheeler

All Physics Faculty Publications

We find the field equations of biconformal space in a basis adapted to Lagrangian submanifolds on which the restriction of the Killing metric is non-degenerate.

Go to article

Studies In Torsion Free Biconformal Spaces. Case 2: \Gamma_{-} = 0, James Thomas Wheeler Jan 2015

Studies In Torsion Free Biconformal Spaces. Case 2: \Gamma_{-} = 0, James Thomas Wheeler

All Physics Faculty Publications

We show that the solutions for the symmetric part of the connection in homogeneous biconformal space also satisfy the more general field equations of curved biconformal spaces in the case when \gamma_{-} = 0.

Go to article

First Prev Next Last