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Full-Text Articles in Physics
On-Shell Representations Of Two-Body Transition Amplitudes: Single External Current, Raúl A. Briceño, Andrew W. Jackura, Felipe G. Ortega-Gama, Keegan H. Sherman
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 …
Simultaneous Monte Carlo Analysis Of Parton Densities And Fragmentation Functions, Eric Moffat, W. Melnitchouk, Ted C. Rogers, N. Sato, Jefferson Lab Angular Momentum Collaboration
Simultaneous Monte Carlo Analysis Of Parton Densities And Fragmentation Functions, Eric Moffat, W. Melnitchouk, Ted C. Rogers, N. Sato, Jefferson Lab Angular Momentum Collaboration
Physics Faculty Publications
We perform a comprehensive new Monte Carlo analysis of high-energy lepton-lepton, lepton-hadron and hadron-hadron scattering data to simultaneously determine parton distribution functions (PDFs) in the proton and parton to hadron fragmentation functions (FFs). The analysis includes all available semi-inclusive deep-inelastic scattering and single-inclusive e+e− annihilation data for pions, kaons and unidentified charged hadrons, which allows the flavor dependence of the fragmentation functions to be constrained. Employing a new multistep fitting strategy and more flexible parametrizations for both PDFs and FFs, we assess the impact of different datasets on sea quark densities and confirm the previously observed suppression …