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EIC Global Studies

Latest news

• A few notes from the pion/kaon workshop, as well as suggestions for next steps for our kaon (pion) modeling based on discussion with Nobuo below. Perhaps we can have a meeting in mid-June to discuss these further.
  • (Nick) Finalize reproducing pion global fit. Two possible issues that may be the reason for observed mismatch with F2_LN y-dependence in Fig. 6 of PRD 93, 054011, 2016:

k_perp integration has experimental cutoffs not stated explicitly in 2016 paper - cutoffs listed in paper by H1 collaboration
x is x_Bjorken, not x_pi in these figures

• • (Nick, Nobuo, Tanja, ...) Develop global fit for kaons - two steps:

Develop model to determine relative numbers of kaons produced - could use pion data and parameterize flux factor
Adapt pion global fit framework for kaons - Python or Mathematica

• • (Richard, Nobuo,...) Test impact of current theory assumptions on pion global fit by releasing (see 2018 paper or Nobuo's talk for details):

momentum sum rules
symmetric sea
splitting function exponent at high x
parameters

• • (Richard, Vladimir, Tanja,...) Use fixed statistical uncertainties (1%, 3%, 10%) and determine corresponding experimental conditions (luminosity, detector acceptance and resolution) for pion structure function measurements at EIC; ultimately need to use realistic binning and projected statistics from Fast Monte Carlo and detector simulation; repeat for kaon
  • Note on Nobuo et al. 2018 paper: uses Nobuo's own fit to nucleon PDFs instead of HERAPDF1.5 that was used in PRD 93 (2016). Also, several theoretical assumptions are made that make errors in Fig. 2 appear very small - not all are justifiable experimentally. Needs to be investigated

• Key questions defining a new program on origin of (hadron) mass and goals of the workshop. Further details in the attached write-up by Craig Roberts.
  • How do mass and radii of light quark systems (pion/kaon) emerge from QCD - role of dynamical chiral symmetry breaking
  • Interplay of strong mass and Higgs mechanism
  • Possible contribution of theory, experiment, global fits, phenomenology, lattice, as discussed during workshop:
  • Theory: decomposition of mass, contributions from quarks and gluons in energy-momentum tensor whose moments are related to Parton Distribution Functions (PDFs and GPDs), and structure functions and form factors, which can be measured; fundamental questions include: how cancellations work to end up with pion mass, how mass decomposition works in chiral limit; pion and kaon are fundamental: pion mass is unnaturally light, kaon has one heavy quark and can provide information on strong and Higgs mass production mechanism
  • Lattice: calculate expectation values (matrix elements as function of quark mass, moments of PDFs) towards mass decomposition, chiral limit?

Experiment/Global Fit: feasibility and projections for pion and kaon structure function and form factor measurements at EIC, models for rate projections, rates, requirement on detectors, e.g. calorimeter resolution, neutral vs. charged particle detection, etc., global fits and impact on PDFs and GPDs, feasibility of measurement with heavier quarks (charm) in addition to pi/K 

Simulations and web fitter global fits

Simulations	⇒
Web Fitter	⇒

NPS Crystal Test Planning

Summary from 10/27/2015 meeting

Participants: MAPC, SA, TH, MB, ILP

Measurement of Transmittance using Spectrometer Lambda 750

Transverse Transmittance (stepper motor)

• Testing Subset of Crystals
• Micro-switch to be bypassed for operation with opened door?
  • Can anything be damaged if someone opens the machine while operating it?
  • Would any accidental light leak be detrimental to the experiment?

    • See Perkin-Elmer L750 manual
    • Contact company to find out more info (MAPC, Marek)

• Conceptual Test for the stepper motor inside the spectrometer
  • Next week: (11/2 – 11/6) - Test with a black cloth.

Longitudinal Transmittance

• Testing Subset of Crystals
• What is the purpose of the windows? Should we remove them?

X-ray Irradiation

• Check with CUA radiation safety before testing machine. (TH, Miguel P., ILP)
• Can we move instrument downstairs?
• Clean room in which instrument is located
• Consult CP160 manual (Miguel P., NP group)
• Check radiation requirements
• Think about measurement of accumulated dose. Is there something in the instrument?
  • Search for options of dosimeters (CUA/JLab/internet).
  • Check out instrument
  • Calibration scheduling (TH, ILP, Miguel P.).

The EIC Collaboration

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