Pion-LT (E12-19-006)

Experiment Overview¶

The pion occupies a special place in nature as one of the lightest hadrons, with one valence quark, and one valence antiquark. Small as it might be, the pion is also responsible for the long range character of the strong interaction that binds the atomic nucleus together. If chiral symmetry, which implies that Dirac Fermions are massless, were an exact global symmetry of strong interactions then pions would be massless. Through gluon-quark interaction and by explicit inclusion of light quark masses, chiral symmetry of massless QCD undergoes explicit symmetry breaking, thus giving the pion its mass. This puts the pion at the core of the mechanism that dynamically generates all the mass of the hadrons and makes it a crucial element in understanding hadron structure. Globally, this experiment will aim to confirm the potential of pion measurements both for studies of the pion structure itself and of the 3D structure of the proton, in terms of spatial imaging (tomography).

This joint experiment will make precise measurements of the L/T separated pion electroproduction cross section at low Q2. E12-07-105 aim is to probe conditions for factorization of deep exclusive measurements for charged pions in GPD studies and the pion form factor. The results may be useful in constraining the longitudinal backgrounds in the extraction of the pion form factor from pion electroproduction data. In addition, measurements in non-parallel kinematics will allow for simultaneous extraction of the interference terms and serve as a test of t-dependence of the π+ cross section. The E12-06-101 experiment will make precise measurements at low Q2 from which we will test the method by which we can further test methods to extract the pion form factor.
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E12-06-101 and E12-07-105 Documents¶

• Proposals:
  • E12-07-105
  • E12-06-101
  • PAC-44 Jeopardy Document jeopardy_pac19.pdf

• Hall C Wiki
• Hall C Electronic Logbook
• Hall C Information
• Experiment Schedule

Run Information¶

• Run Plans and Run Sheets
• PionLT Specific Shift Instructions
• Online Analysis Instructions
• Experimental Safety Asessment Documentation Summer 2019
• Conduct of Operations Summer 2019
• Information for Shift Takers
• Documentation for Running Hall C
• Beam Schedule
• Shift Signup
• Shift Signup, read only
• Hall C How-Tos: 1 , 2
• Analysis on Cdaq
• Contact Experts

Data Analysis¶

• UTIL_PION Git Repository
• SIMC
• Hall C Analyzer
• Online Replay Histograms
• Joint Hall A & C Data Analysis
• L/T Separation Software (see Sec 4.2 of https://misportal.jlab.org/ul/publications/view_pub.cfm?pub_id=15234 for description)

Meetings¶

• Hall C Commissioning Analysis Meetings
• Detector Working Group Meetings
• Pion LT Meetings
• BlueJeans Information

Collaboration¶

• Spokespersons
• Collaboration List
• Mailing List