20200720-Optics-Mtg

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Logistic information

 Toll-Free Number (U.S.&  Canada):  888-240-2560
 PARTICIPANT CODE:                  # 585 129 220
 Room IRL:                            <none>
 https://bluejeans.com/585129220

Agenda

Please post slides in haplog or docdb, before the meeting

  1. Last weeks issues:
    • Non-symmetric azimuthal angle acceptance distributions
    • instability in Q2 measurements over the PREX-2 run Ryan
    • catalog of relevant parameters for Q2 runs (beam E, beam position, spectrometer dp, trigger hole?... others?)
    • Lead uniformity measurement vs. target lifetime (expected failure at end only)
  2. Longstanding topics
    • progress on MC simulation of acceptance function
    • Carbon fraction
    • ultimate precision of angle measurement
    • evaluation of optics db reconstruction uncertainty to q2 / acceptance function systematic error
    • inelastic contamination Devi

Minutes

  1. (Chandan) Acceptance function Chandan
    • Started MC simulation of acceptance function
    • shows lower Q2 than data, but still work to be done to match scattering angles, etc.
    • reasonable looking reconstruction distribution, but very confusing dp from "target" vs "fp". Will talk to ryan about definitions for these variables.
  2. (Devi) Inelastic study -
    • fit of CREX spectrum leads to estimate of inelastic strengths
    • estimate of acceptance function.
    • can be improved by convoluting acceptance and inelastic distributions
    • Asymmetry estimates for inelastic states needed to complete this analysis.
    • PREX-1 showed 3- excitation in thin lead target spectrum, looking for thi

s data to try to improve estimate of inelastic cross-section

  1. (Ryan) Q2 consistency
    • After the first Q2 runs on natural lead (June 27) the other runs look more similar.
    • reconstructed variables look similar, though dp for the 2nd natural lead run are narrower than other runs, and sometimes with small shifts.
    • will need to accumulate the database of info for each run, on beam position, energy, spectrometer dp, etc.

[ https://docs.google.com/spreadsheets/d/1KpI4E1YjqStms2q5VfgF-9d2sTuG7s-OcBEuBSGxnyU/edit?usp=sharing Q2 run summary]

  1. (Siyu) Looking at non-uniformity for estimate of changes in lead density
    • sees "average density" rise and fall - proabably not sufficient to normalize to one corner as in PREX-1
    • Stabilty of width suggests limits on time variation of density. (Devi has a plot on this, should be remade with Tao's newest analysis of respin-2).
    • Unusual difference between target uniformity distribution when cut on detector his vs detector not hit. maybe thickening of target in some areas causing radiative losses?

Attendence

Dustin, chandan, bob, cameron, devi, hanjie, ryan, siyu, nilanga , cip, kent