Discussion 06-17-24

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Speakers and participants, please review the guidance provided on the main page. This agenda page is editable by anyone that has a Jefferson Lab computing account. Feel free to log in and post comments, questions, or answers to questions in the section below.

Meeting Location

The 22 GeV Open Discussions will be held here:

  • Date/Time: Monday, June 17 at 12:30 PM Jefferson Lab Local Time
  • Physical Location: CEBAF Center F224/5
  • Virtual Location: Zoom Meeting Number 161 111 8017 (The password is the two-digit number that appears before "GeV" in the first sentence of this section.

Agenda

Comments and Questions

  • To avoid confusion in presenting to a broader audience the role of our knowledge of gravity should be clarified in the measurement.
    • The objective is to measure the stress-energy tensor of the proton. The classical stress-energy tensor also appears in the Einstein field equations which relate this tensor to the curvature of space-time; however, our knowledge of gravity, i.e., the theory of General Relativity, is not relevant for making the measurement.
    • Unlike electromagnetic or weak probes, the particles being used to probe the proton in such experiments are not mediators of the gravitational force.
  • What prediction is being tested by measuring the pressure as a function of radius? What behavior of QCD is being probed? What level of precision on the measurement of the pressure is required to draw conclusions about these tests?
  • The final projected precision of pressure as a function of radius at 22 GeV includes uncertainties from both theory and experiment. What are the appropriate assumptions about the theoretical systematic uncertainties?
  • Are both deeply virtual Compton scattering and threshold J/ψ production measuring the same properties of the proton? How are they complementary? Should the experimental results lead to the same conclusion?
    • It is clear that DVCS should probe the quarks and not the gluons. It is less clear, in the case of J/ψ, why the gluon exchange doesn't also probe the quarks.