Eugene Pasyuk - Academia.edu (original) (raw)

Papers by Eugene Pasyuk

Jefferson Lab - CEBAF. Measurement of the differential cross section for the photoproduction reac... more Jefferson Lab - CEBAF. Measurement of the differential cross section for the photoproduction reaction GAMMA P --& gt; P PI0 for tagged photon incident energiesfrom 0.675 to 2.875 GeV. The data were taken during the g1c run in Hall B with two running periods having electron beam energies 2.445 and 3.115 GeV respectively and a liquid hydrogen target.. Numerical values supplied by M Dugger.

arXiv: Nuclear Experiment, 2020

We propose to create a secondary beam of neutral kaons in Hall D at Jefferson Lab to be used with... more We propose to create a secondary beam of neutral kaons in Hall D at Jefferson Lab to be used with the GlueX experimental setup for strange hadron spectroscopy. The superior CEBAF electron beam will enable a flux on the order of 1times104K˜L/sec1\times 10^4~K_L/sec1times104K˜L/sec, which exceeds the flux of that previously attained at SLAC by three orders of magnitude. The use of a deuteron target will provide first measurements ever with neutral kaons on neutrons. The experiment will measure both differential cross sections and self-analyzed polarizations of the produced Lambda\LambdaLambda, Sigma\SigmaSigma, Xi\XiXi, and Omega\OmegaOmega hyperons using the GlueX detector at the Jefferson Lab Hall D. The measurements will span CM costheta\cos\thetacostheta from −0.95-0.95−0.95 to 0.95 in the range W = 1490 MeV to 2500 MeV. The new data will significantly constrain the partial wave analyses and reduce model-dependent uncertainties in the extraction of the properties and pole positions of the strange hyperon resonances, and establish the orbitally excited multipl...

arXiv: Nuclear Experiment, 2019

Positron beams, both polarized and unpolarized, are identified as essential ingredients for the e... more Positron beams, both polarized and unpolarized, are identified as essential ingredients for the experimental program at the next generation of lepton accelerators. In the context of the Hadronic Physics program at the Jefferson Laboratory (JLab), positron beams are complementary, even essential, tools for a precise understanding of the electromagnetic structure of the nucleon, in both the elastic and the deep-inelastic regimes. For instance, elastic scattering of (un)polarized electrons and positrons off the nucleon allows for a model independent determination of the electromagnetic form factors of the nucleon. Also, the deeply virtual Compton scattering of (un)polarized electrons and positrons allows us to separate unambiguously the different contributions to the cross section of the lepto-production of photons, enabling an accurate determination of the nucleon Generalized Parton Distributions (GPDs), and providing an access to its Gravitational Form Factors. Furthermore, positron ...

Physical Review Letters, 2021

The European Physical Journal A, 2021

Systematic differences in the the proton's charge radius, as determined by ordinary atoms and muo... more Systematic differences in the the proton's charge radius, as determined by ordinary atoms and muonic atoms, have caused a resurgence of interest in elastic lepton scattering measurements. The proton's charge radius, defined as the slope of the charge form factor at Q 2 =0, does not depend on the probe. Any difference in the apparent size of the proton, when determined from ordinary versus muonic hydrogen, could point to new physics or need for the higher order corrections. While recent measurements seem to now be in agreement, there is to date no high precision elastic scattering data with both electrons and positrons. A high precision proton radius measurement could be performed in Hall B at Jefferson Lab with a positron beam and the calorimeter based setup of the PRad experiment. This measurement could also be extended to deuterons where a similar discrepancy has been observed between the muonic and electronic determination of deuteron charge radius. A new, high precision measurement with positrons, when viewed alongside electron scattering measurements and the forthcoming MUSE muon scattering measurement, could help provide new insights into the origins of the proton radius puzzle, and also provide new experimental constraints on radiative correction calculations.

The European Physical Journal A, 2021

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2021

We report on a windowless, high-density, gas flow target at Jefferson Lab that was used to measur... more We report on a windowless, high-density, gas flow target at Jefferson Lab that was used to measure r p , the root-mean-square charge radius of the proton. To our knowledge, this is the first such system used in a fixed-target experiment at a (non-storage ring) electron accelerator. The target achieved its design goal of an areal density of 2×10 18 atoms/cm 2 , with the gas uniformly distributed over the 4 cm length of the cell and less than 1% residual gas outside the cell. This design eliminated scattering from the end caps of the target cell, a problem endemic to previous measurements of the proton charge radius in electron scattering experiments, and permitted a precise, model-independent extraction of r p by reaching unprecedentedly low values of Q 2 , the square of the electron's transfer of four-momentum to the proton.

Physical Review Letters, 2019

arXiv: Nuclear Experiment, 2020

arXiv: Nuclear Experiment, 2019

Physical Review Letters, 2021

The European Physical Journal A, 2021

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2021

Physical Review Letters, 2019