We report high-precision measurements of the Deeply Virtual Compton
Scattering (DVCS) cross section at high values of the Bjorken variable $x_B$.
DVCS is sensitive to the Generalized Parton ...Distributions of the nucleon, which
provide a three-dimensional description of its internal constituents. Using the
exact analytic expression of the DVCS cross section for all possible
polarization states of the initial and final electron and nucleon, and final
state photon, we present the first experimental extraction of all four
helicity-conserving Compton Form Factors (CFFs) of the nucleon as a function of
$x_B$, while systematically including helicity flip amplitudes. In particular,
the high accuracy of the present data demonstrates sensitivity to some very
poorly known CFFs.
Phys. Rev. Lett. 127, 152301 (2021) We report measurements of the exclusive neutral pion electroproduction cross
section off protons at large values of $x_B$ (0.36, 0.48 and 0.60) and $Q^2$
(3.1 to ...8.4 GeV$^2$) obtained from Jefferson Lab Hall A experiment E12-06-014.
The corresponding structure functions $d\sigma_L/dt+\epsilon d\sigma_T/dt$,
$d\sigma_{TT}/dt$, $d\sigma_{LT}/dt$ and $d\sigma_{LT'}/dt$ are extracted as a
function of the proton momentum transfer $t-t_{min}$. The results suggest the
amplitude for transversely polarized virtual photons continues to dominate the
cross-section throughout this kinematic range. The data are well described by
calculations based on transversity Generalized Parton Distributions coupled to
a helicity flip Distribution Amplitude of the pion, thus providing a unique way
to probe the structure of the nucleon.
We report high-precision measurements of the Deeply Virtual Compton Scattering (DVCS) cross section at high values of the Bjorken variable \(x_B\). DVCS is sensitive to the Generalized Parton ...Distributions of the nucleon, which provide a three-dimensional description of its internal constituents. Using the exact analytic expression of the DVCS cross section for all possible polarization states of the initial and final electron and nucleon, and final state photon, we present the first experimental extraction of all four helicity-conserving Compton Form Factors (CFFs) of the nucleon as a function of \(x_B\), while systematically including helicity flip amplitudes. In particular, the high accuracy of the present data demonstrates sensitivity to some very poorly known CFFs.
We report measurements of the exclusive neutral pion electroproduction cross section off protons at large values of \(x_B\) (0.36, 0.48 and 0.60) and \(Q^2\) (3.1 to 8.4 GeV\(^2\)) obtained from ...Jefferson Lab Hall A experiment E12-06-014. The corresponding structure functions \(d\sigma_L/dt+\epsilon d\sigma_T/dt\), \(d\sigma_{TT}/dt\), \(d\sigma_{LT}/dt\) and \(d\sigma_{LT'}/dt\) are extracted as a function of the proton momentum transfer \(t-t_{min}\). The results suggest the amplitude for transversely polarized virtual photons continues to dominate the cross-section throughout this kinematic range. The data are well described by calculations based on transversity Generalized Parton Distributions coupled to a helicity flip Distribution Amplitude of the pion, thus providing a unique way to probe the structure of the nucleon.
The E12-10-002 (F2) experiment ran in Hall C at JLab to extract the F2 structure functions of proton and neutron from inclusive H(e, e′) and D(e, e′) reactions in the high Bjorken x region. Those ...extractions put constraints on the Parton Distribution Functions PDFs (especially at large Bjorken x), and facilitate the study of Quark Hadron Duality. The F2 experiment measurements covers a large kinematic range in x from 0.2 to 1.0, and in Q2 from 4 to 16 GeV2.While the proton F2 structure function has been studied extensively through in-elastic electron-proton scattering, much less is known about neutron structure due to the unavailability of high density, free neutron targets. The BONuS12 experiment was proposed to measure the neutron F2 on a nearly free neutron within a weakly bound deuteron target via the spectator tagging method. Tagging the slow backwardmoving spectator protons minimizes both off-shell and final-state interaction effects, and the measured proton momentum is used to correct for the initial-state momentum of the struck neutron. The recoil detector is used to detect spectator protons with momenta 70 < ps < 150 MeV/c. This dissertation outlines the design, construction and testing of the recoil detector, Radial Time Projection Chamber (RTPC) and discusses the results of the H(e, e′) and D(e, e′) cross sections and the F2 structure functions obtained from the Hall C F2 data analysis.
