Apr 27/23 PionLT/KaonLT Analysis Meeting Notes ----------------------------------------------- (Notes by GH and SJDK) Today: KaonLT will be discussed first Please remember to post your slides at: https://redmine.jlab.org/projects/kltexp/wiki/Kaon_LT_Meetings Present ------- Regina - Stephen Kay, Garth Huber, Muhammad Junaid, Ali Usman, Alicia Postuma, Nathan Heinrich, Vijay Kumar, Love Preet CUA - Tanja Horn, Richard Trotta Ohio - Julie Roche, Jacob Murphy FIU - Pete Markowitz JLab - Dave Gaskell, Peter Bosted CSULA - Konrad Aniol Richard Updates --------------- Tracking/lumi updates - Recap from 6/4/23 meeting, some runs were outside of the general trend - Bad TLT? - Will discuss with Jacob tomorrow about TLT calculation - if the TLT calc is fine, then will need to look more closely at the running conditions, and try to figure out what's wrong with these runs Pion/proton subtraction, normalized to pi+n p+omega peaks - Pion subtraction looking pretty good - Proton subtraction dosn't look so good - somehow the proton distribution is missing the omega peak, but it does show substantial pi+n leakthrough, and also a small K+Lambda peak - GH: it's essential that the pion and proton spectra used for background subtraction are clean, as otherwise you will subtract K+ too - No hole cut on HGC - Just <= 1.5 on HGC for proton sample, which allows pi,K near hole - SK: Apply proton PID cuts, keep -5 to 5 in CT, then plot MM vs CT, see where 0.8 GeV peak is popping up - No Ref time cuts for pion/proton spectra - also need to re-check proton CT cuts - PeterB: What is the momentum here? - 10.6 GeV data, SHMS ~ 6 GeV/c - Pion/Proton are 0.5~ns separated in CT at 6 GeV/c - Meeting with Ali on HGC next week - HGC is the top priority going forward - To Do: Want to look at BPM calibrations too Vijay Updates ------------- Ratio of SIMC/Experimental yields - 8 t bins - 16 phi bins - plots at high, mid, low epsilon to show the code is working - Experimental yields not finalized, so shouldn't expect much yet - Ratios generally sensible for high, mid, low and low epsilon given the lack of iterations, but the phi distribution has a weird dip - thinks it's a SIMC model issue - DaveG: Could be an artifact of not having offsets, they aren't finalised yet - Peter B: is the 2.7-3 mrad Out of plane offset in? - Typical offset used for coincidence experiments - No, net yet - Need to move back to yields, experimental data will move bin to bin - GH: Do not have SIMC model issues, you have experimental issues - Need to finalise offsets, rate dependencies etc then can come back to this - the data will migrate between different phi-bins, depending on the offset, so don't worry about the model or LT-sep until this is finalized and applied Nathan Updates -------------- Finished aerogel calibrations - Updated slides from last week, on redmine already - Added new calibrations files and updated databases to git - GH: Will have to check Redmine, do we have an area for calibrations? - If not, maybe a new area for this would be nice - otherwise, your final slides on the calibration will be difficult to locate First look at the HMS cherenkov calibration - Got the existing code going - Ran for 15-20 runs or so - GH: Selecting pi- to do the calibration? - Dave G - No, don't need pions to be high momentum, better to use delta knock-on electrons as source of low PE events - PeterB: Use a run with a lower momentum setting for two reasons 1) Higher pi- to e- ratio at low P 2) Lack of pi- Cherenkov radiation - Threshold set to 4.5 GeV/c? - Dave G - Sounds about right - Picked a random set of runs between 12000-16000, just ran them to check what they look like - Will do a more systematic pass now, looking more carefully at the pi-/e- ratio (see runplan spreadsheets) and the pi- Cherenkov threshold Junaid Updates -------------- HMS DC calibrations - 9.2 GeV beam energy, 2021 run - Applied electron cuts (HMS Cer NPE Sum > 1.5, HMS ETotNorm > 0.7) RED=before calib, BLUE=after calib - Residuals mostly improved, but still get double-peaked distributions for some planes - changed a few parameters and still waiting on second replay - DaveG: Does the code work by doing groups of 16 wires or individual wires? - Not sure, will need to check. Not sure whether groups of 8 or 16 wires are used - Dave G: Time window cuts are applied? - Yes - GH: Who has the HMS calorimeter on their list? - Junaid - Working on calorimeter already too, modifying batch script - SK: Reminder to be a bit more selective with SHMS calorimeter calibrations, only want -ve polarity runs Ali Updates ----------- Heep Coin Analysis, offset studies - Richard talked about the new SIMC kinematic variable calculations in the Quarterly Analysis Meeting - Using these when comparing with data - Last week reported a constant 13 MeV shift in out of plane offset (Pmy) in all kinematics - Juanid: What is the physical origin of the OOP offset? - AU: Correspondence to difference between two reaction/scattering planes compared to what we actually think - HeeP reaction is inherently coplanar - Physically, comes from spectrometer misalignment? - Dave G: Could be something in carriage that isn't flat, not pointing correctly - PeterB: Mark Jones believes it's a property of the magnets, magnetic axis of one spectrometer is a little bit offset - changes ThetaE (xptar) and adds 0.0027 to it - seems to be a property of the spectrometer, also had similar offset in 6 GeV era - Add 2.7 mrad to -xptar (theta_e angle) - Lots of ways to check it, HeeP, asymmetries - TH: Yes, had two offsets in this era too - DG: Look at Fig 3.11 in TH thesis - First look at Out of plane offset - Constant 13 MeV PMy shift - An angle offset works out into a momentum offset when you calculate momentum quantities, as a percentage of the spectrometer central momentum - Tried applying offset to SHMS first, smaller range of central momenta - found the angle offset needed to put PMy near zero - Plotted Pmy offset vs SHMS momentum - 6.2 beam: 0.0038 - 8.2, 10.2 beam: both are 0.0030 - projecting to higher P_SHMS would give significantly smaller offsets for physics settings - Dave G/Tanja: How can you do this for Physics settings? Not kinematically constrained? - Could just use 0.003 everywhere - Tanja - Can't just use an offset/make one up to fix the data - These are just projections/expectations for physics offsets - GH: Should get error bars for three HeeP points, based on the widths of the PMy distributions, then I expect you will find a flat fit will be sufficient - Vijay: How can you get OOP offset without getting other offsets - Garth - OOP offset is independent of the others, since Heep reaction is coplanar - the HeepCheck program only gives the in-plane offsets - Can set/fix OOP offset, then use the HeepCheck program to get the rest, OOP offset is separate - Need to determine OOP first before determining the others - Didn't really fully appreciate this until last week - Vijay: Even after adjustment from Richard, plots still don't match - Ali: Yes but this is a limitation of the data - PeterB: What does Pmy correspond to? - xptar - PeterB: Actually looked at asymmetries of exclusive pions to determine this offset, didn't really have enough HeeP runs - Should take the events, calculate angle between two planes for HeeP settings you have - also looked at the azimuthal asymmetry of the exclusive pi+ events, although this is tricky because of the interference terms - PeterB: Previously found that it was more consistent to apply the offset to the HMS - Offset was consistent in 6 GeV era, only spectrometer in common is the HMS, implies it's an HMS issue - please try an HMS offset and see how well it works - DaveG: Figure 3.11 in Tanja’s thesis has a nice description of how to separate HMS and SHMS out of plane offsets - Peter is applying offset directly to xptar - GH: How do you do this? - recall that PB recalculates all variables from scratch via a script - xptar += 0.0027, manually reconstruct whatever is shifted - Recalculate all Physics variables from xptar etc - Only read in non-offset data from the replay - Plot coplanarity delta - Do it for all settings, see if coplanarity offset is independent of momentum - CYero found a slight dependence in the offset, but basically the same as PB - TH: it's important for everyone to be familiar with what was done in her thesis, Peter and Carlos work, etc. - try to learn from everyone's experience and not lose time working out the procedure Very useful offsets discussion. Summary to things for Ali: - review TH, CY theses offsets discussions - try an HMS OOP offset - try estimating errors in each OOP offset as this affects what conclusions to draw when extrapolating to physics settings Alicia Updates -------------- - Finished exams on Tuesday - Hopefully something to show next meeting - Experimenting with HGC cuts to see if it makes any difference in BSA data - Getting SIMC running - MM changed significantly as a function of t - would like to see that pi+n peak looks like versus t - Hopefully some of this to show for next week Jacob Updates ------------- - Welcome back Jacob :) - will meet with Junaid and Nathan next week - PeterB asks about the status of optics - can show some delta-optimizations next week Next Meeting ------------ - Thur May 4 @ 16:00 Eastern/14:00 Regina/13:00 Pacific - PionLT will go first