I. MacGregor

activity

20042026

most citedMeasurement of the Electric Form Factor of the Neutron at Q^2 = 0.3-0.8 (GeV/c)^2

145 citations · 1.3k across the 65 of their papers we have counts for

collaborators

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47 papers · 1 filter

nucl-ex2026

First measurement of polarized spin-density matrix elements and differential cross sections d $σ$ /d $t$ in $ω$ ~photoproduction off the proton for $2.7 < E_{γ} < 5.2$ GeV using CLAS at Jefferson Lab

T. Hu, Z. Akbar, V. Crede +147

We report on the differential cross sections d $σ$ /d $t$ , the unpolarized spin-density matrix elements $ρ_{00}^{0}$ , $ρ_{1 - 1}^{0}$ , Re\, $ρ_{10}^{0}$ , and the first extraction of the polari…

nucl-ex2026

Measurements of $γ_{v} p \to π^{+} π^{-} p^{'}$ Cross Sections with the CLAS Detector for $Q^{2}$ from 2.0--5.0~GeV $^{2}$ and $W$ from 1.400--2.125~GeV

A. Trivedi, R. W. Gothe, E. Phelps +155

Observables in the electroproduction of the $π^{+} π^{-} p$ reaction channel off the proton that are sensitive to the polarization of the virtual photon are presented for the first time…

nucl-ex2025

Recoil Polarization in $K^{+} Y$ Electroproduction in the Nucleon Resonance Region with CLAS12

D. S. Carman, A. D'Angelo, L. Lanza +127

Hyperon recoil polarization measurements for the exclusive electroproduction of $K^{+} Λ$ and $K^{+} Σ^{0}$ final states from an unpolarized proton target have been carried out using the C…

nucl-ex2025

Measurement of single- and double-polarization observables in the photoproduction of $π^{+} π^{-}$ ~meson pairs off the proton using CLAS at Jefferson Laboratory

P. Roy, S. Cao, V. Crede +141

The photoproduction of $π^{+} π^{-}$ meson pairs off the proton has been studied in the reaction $γ p \to p π^{+} π^{-}$ using the CEBAF Large Acceptance Spectrometer (CLAS) and the frozen-sp…

nucl-ex2024

Photoproduction of two charged pions off protons in the resonance region

A. V. Sarantsev, E. Klempt, K. V. Nikonov +4

Photoproduction of charged pions pairs off protons is studied within the invariant masses of the final state hadrons from 1.6 to 2.4 GeV at the Thomas Jefferson National Accelerato…

nucl-ex2024★ 2 cited

Measurement of the nucleon spin structure functions for 0.01< $Q^{2}$ <1 GeV $^{2}$ using CLAS

A. Deur, S. E. Kuhn, M. Ripani +147

The spin structure functions of the proton and the deuteron were measured during the EG4 experiment at Jefferson Lab in 2006. Data were collected for longitudinally polarized elect…

nucl-ex2024

Dihadron Azimuthal Correlations in Deep-Inelastic Scattering Off Nuclear Targets

CLAS Collaboration

We measured the nuclear dependence of the di-pion azimuthal correlation function in deep-inelastic scattering (DIS) using the CEBAF Large Acceptance Spectrometer (CLAS) and a 5 GeV…

nucl-ex2024

First measurement using elliptically polarized photons of the double-polarization observable $E$ for $γ p \to p π^{0}$ and $γ p \to n π^{+}$

A2 Collaboration, F. Afzal, K. Spieker +74

We report the measurement of the helicity asymmetry $E$ for the $p π^{0}$ and $n π^{+}$ final states using, for the first time, an elliptically polarized photon beam in combination with…

nucl-ex2023★ 2 cited

Helicity dependent cross sections for the photoproduction of $π^{0} π^{\pm}$ pairs from quasi-free nucleons

A2 Collaboration, D. Ghosal, V. Sokhoyan +71

Photoproduction of $π^{0} π^{\pm}$ -pairs from quasifree nucleons bound in the deuteron has been investigated to study the helicity dependence of this reaction. Measurements with a liq…

nucl-ex2023

Double-pion electroproduction off protons in deuterium: Quasifree cross sections and final-state interactions

Iu. A. Skorodumina, G. V. Fedotov, R. W. Gothe +1

The single-differential and fully integrated cross sections for quasifree $π^{+} π^{-}$ electroproduction off protons bound in deuterium have been extracted for the first time. The…

nucl-ex2023

Beam Spin Asymmetry Measurements of Deeply Virtual $π^{0}$ Production with CLAS12

A. Kim, S. Diehl, K. Joo +154

The new experimental measurements of beam spin asymmetry were performed for the deeply virtual exclusive $π^{0}$ production in a wide kinematic region with the photon virtualities $Q…

nucl-ex2023★ 19 cited

Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab

A. Accardi, P. Achenbach, D. Adhikari +441

This document presents the initial scientific case for upgrading the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLab) to 22 GeV. It is the result of a…

nucl-ex2023

Measurement of the helicity asymmetry $E$ for the $γ p \to p π^{0}$ reaction in the resonance region

K. Chan, N. Zachariou, M. Bashkanov +9

The double-spin-polarization observable $E$ for $γ p \to p π^{0}$ has been measured with the CEBAF Large Acceptance Spectrometer (CLAS) at photon beam energies $E_{γ}$ …

nucl-ex2022

Neutron polarisation transfer, $C_{x^{'}}^{n}$ , in $π^{+}$ photoproduction off the proton

M. Bashkanov, D. P. Watts, S. J. D. Kay +63

We report a first measurement of the double-polarisation observable, $C_{x^{'}}$ , in $π^{+}$ photoproduction off the proton. The $C_{x^{'}}$ double-polarisation observable represents the t…

nucl-ex2022

First Measurement of $Λ$ Electroproduction off Nuclei in the Current and Target Fragmentation Regions

T. Chetry, L. El Fassi, W. K. Brooks +151

We report results of $Λ$ hyperon production in semi-inclusive deep-inelastic scattering off deuterium, carbon, iron, and lead targets obtained with the CLAS detector and the Contin…

nucl-ex2022★ 1 cited

Exclusive $π^{-}$ Electroproduction off the Neutron in Deuterium in the Resonance Region

Y. Tian, R. W. Gothe, V. I. Mokeev +140

New results for the exclusive and quasi-free cross sections off neutrons bound in deuterium $γ_{v} n (p) \to p π^{-} (p)$ are presented over a wide final state hadron angle rang…

nucl-ex2022★ 1 cited

Measurement of the helicity dependence for single $π^{0}$ photoproduction from the deuteron

The A2 collaboration, F. Cividini, M. Dieterle +72

The helicity-dependent single $π^{0}$ photoproduction cross section on the deuteron and the angular dependence of the double polarisation observable $E$ for the quasi-free single $…

nucl-ex2021

Measurement of Compton scattering at MAMI for the extraction of the electric and magnetic polarizabilities of the proton

A2 Collaboration, E. Mornacchi, P. P. Martel +65

A precise measurement of the differential cross-sections $d σ / d Ω$ and the linearly polarized photon beam asymmetry $Σ_{3}$ for Compton scattering on the proton below pion threshold ha…

nucl-ex2021★ 28 cited

Measurement of charged-pion production in deep-inelastic scattering off nuclei with the CLAS detector

S. Moran, R. Dupre, H. Hakobyan +141

Background: Energetic quarks in nuclear DIS propagate through the nuclear medium. Processes that are believed to occur inside nuclei include quark energy loss through medium-stimul…

nucl-ex2020★ 9 cited

Helicity-dependent cross sections for the photoproduction of $π^{0}$ pairs from nucleons

M. Dieterle, L. Witthauer, A. Fix +88

The double-polarization observable $E$ and helicity-dependent cross sections $σ_{1/2}$ , $σ_{3/2}$ have been measured for the photoproduction of $π^{0}$ pairs off quasi-free protons a…

nucl-ex2020★ 102 cited

Probing the core of the strong nuclear interaction

A. Schmidt, J. R. Pybus, R. Weiss +162

The strong nuclear interaction between nucleons (protons and neutrons) is the effective force that holds the atomic nucleus together. This force stems from fundamental interactions…

nucl-ex2020★ 11 cited

First measurement of direct photoproduction of the $a_{2} (1320)^{0}$ meson on the proton

A. Celentano, M. Battaglieri, R. De Vita +4

We present the first measurement of the exclusive reaction $γ p \to a_{2} (1320)^{0} p$ in the photon energy range $3.5$ - $5.5$ GeV and four-momentum transfer squared $0.2<-t<2…

nucl-ex2019★ 14 cited

Spin polarizabilities of the proton by measurement of Compton double-polarization observables

D. Paudyal, P. P. Martel, G. M. Huber +90

The Compton double-polarization observable $Σ_{2 z}$ has been measured for the first time in the $Δ (1232)$ resonance region using a circularly polarized photon beam incident on a lo…

nucl-ex2018★ 23 cited

Measurement of Nuclear Transparency Ratios for Protons and Neutrons

M. Duer, O. Hen, E. Piasetzky +6

This paper presents, for the first time, measurements of neutron transparency ratios for nuclei relative to C measured using the (e,e'n) reaction, spanning measured neutron momenta…

First measurement of polarized spin-density matrix elements and differential cross sections dσ/dt in ω~photoproduction off the proton for 2.7<Eγ​<5.2 GeV using CLAS at Jefferson Lab

Measurements of γv​p→π+π−p′ Cross Sections with the CLAS Detector for Q2 from 2.0--5.0~GeV2 and W from 1.400--2.125~GeV

Recoil Polarization in K+Y Electroproduction in the Nucleon Resonance Region with CLAS12

Measurement of single- and double-polarization observables in the photoproduction of π+π−~meson pairs off the proton using CLAS at Jefferson Laboratory

Photoproduction of two charged pions off protons in the resonance region

Measurement of the nucleon spin structure functions for 0.01<Q2<1 GeV2 using CLAS

Dihadron Azimuthal Correlations in Deep-Inelastic Scattering Off Nuclear Targets

First measurement using elliptically polarized photons of the double-polarization observable E for γp→pπ0 and γp→nπ+

Helicity dependent cross sections for the photoproduction of π0π± pairs from quasi-free nucleons

Double-pion electroproduction off protons in deuterium: Quasifree cross sections and final-state interactions

Beam Spin Asymmetry Measurements of Deeply Virtual π0 Production with CLAS12

Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab

Measurement of the helicity asymmetry E for the γ​p​→pπ0 reaction in the resonance region

Neutron polarisation transfer, Cx′n​, in π+ photoproduction off the proton

First Measurement of Λ Electroproduction off Nuclei in the Current and Target Fragmentation Regions

Exclusive π− Electroproduction off the Neutron in Deuterium in the Resonance Region

Measurement of the helicity dependence for single π0 photoproduction from the deuteron

Measurement of Compton scattering at MAMI for the extraction of the electric and magnetic polarizabilities of the proton

Measurement of charged-pion production in deep-inelastic scattering off nuclei with the CLAS detector

Helicity-dependent cross sections for the photoproduction of π0 pairs from nucleons

Probing the core of the strong nuclear interaction

First measurement of direct photoproduction of the a2​(1320)0 meson on the proton

Spin polarizabilities of the proton by measurement of Compton double-polarization observables

Measurement of Nuclear Transparency Ratios for Protons and Neutrons

First measurement of polarized spin-density matrix elements and differential cross sections d $σ$ /d $t$ in $ω$ ~photoproduction off the proton for $2.7 < E_{γ} < 5.2$ GeV using CLAS at Jefferson Lab

Measurements of $γ_{v} p \to π^{+} π^{-} p^{'}$ Cross Sections with the CLAS Detector for $Q^{2}$ from 2.0--5.0~GeV $^{2}$ and $W$ from 1.400--2.125~GeV

Recoil Polarization in $K^{+} Y$ Electroproduction in the Nucleon Resonance Region with CLAS12

Measurement of single- and double-polarization observables in the photoproduction of $π^{+} π^{-}$ ~meson pairs off the proton using CLAS at Jefferson Laboratory

Measurement of the nucleon spin structure functions for 0.01< $Q^{2}$ <1 GeV $^{2}$ using CLAS

First measurement using elliptically polarized photons of the double-polarization observable $E$ for $γ p \to p π^{0}$ and $γ p \to n π^{+}$

Helicity dependent cross sections for the photoproduction of $π^{0} π^{\pm}$ pairs from quasi-free nucleons

Beam Spin Asymmetry Measurements of Deeply Virtual $π^{0}$ Production with CLAS12

Measurement of the helicity asymmetry $E$ for the $γ p \to p π^{0}$ reaction in the resonance region

Neutron polarisation transfer, $C_{x^{'}}^{n}$ , in $π^{+}$ photoproduction off the proton

First Measurement of $Λ$ Electroproduction off Nuclei in the Current and Target Fragmentation Regions

Exclusive $π^{-}$ Electroproduction off the Neutron in Deuterium in the Resonance Region

Measurement of the helicity dependence for single $π^{0}$ photoproduction from the deuteron

Helicity-dependent cross sections for the photoproduction of $π^{0}$ pairs from nucleons

First measurement of direct photoproduction of the $a_{2} (1320)^{0}$ meson on the proton