Positron Working Group Workshop

Session

PWG - 3

Mar 25, 2025, 8:00 AM

Conveners

PWG - 3

• Eric Voutier (Université Paris-Saclay - CNRS/IN2P3/IJCLab)

23. LDRD for a high-current polarized-beam photogun

Max Bruker (Jefferson Lab)

3/25/25, 8:30 AM

The electron accelerator driving the Ce+BAF conversion target requires a spin-polarized photogun capable of delivering a CW beam current of at least 1 mA. As the high beam current limits the useful operating time of the gun between photocathode reactivations due to ion back-bombardment, it is critical to increase the charge lifetime. A Jefferson Lab LDRD project aims to calibrate the...

24. Solid target project

Silviu Covrig Dusa (Jefferson Lab)

3/25/25, 9:00 AM

25. Liquid target project

Vaclav Kostroun (Xelera Research)

3/25/25, 9:30 AM

41. Degraded beam study of CEBAF

Victor Manuel Lizarraga-Rubio (Universidad de Guanajuato)

3/25/25, 10:30 AM

An electron beam degrader has been installed in the CEBAF injector in support of the positron capabilities of the machine, enabling machine acceptance measurements and testing of large emittance beam transport. This update provides the current state of the project, including proposed beam tests and preliminary results from simulations and previous beam studies.

22. NTPE+ : measurement of the neutron two-photon exchange with quasi-elastic positron-neutron and electron-neutron scattering

Eric Fuchey (College of William and Mary)

3/25/25, 11:00 AM

The first measurements of elastic electron nucleon scattering with polarization transfer, allowing to separate the electric and magnetic nucleon form factors, showed a significant discrepancy with Rosenbluth measurement of the cross section of the same process. The two-photon exchange, suspected to be the cause of this observation, got a major focus since then. The two-photon exchange is...

21. Coulomb corrections in SIDIS

Tyler Hague (JLab)

3/25/25, 11:30 AM

Coulomb Corrections are largely unstudied and unconstrained in SIDIS, just as they are in DIS. Studies have shown that at at typical JLab kinematics, coulomb corrections calculated using the standard Improved Effective Momentum Approximation (IEMA) yield non-negligible corrections to measured cross sections. As the correction is directly proportional to the proton number of the target, any...

20. Two-Photon Exchange in DIS and SIDIS

Michael Nycz (University of Virginia)

3/25/25, 12:00 PM

Discrepancies between extractions of the proton form factor ratio when using Rosenbluth or Polarization transfer techniques has led to a strong interest in measuring the magnitude of two-photon exchange (TPE) effects using the planned CEBAF positron upgrade. TPE in inelastic scattering is comparatively less explored, but its study is well motivated. Two measurements of the imaginary part of...