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Mar 6/25 PionLT/KaonLT Analysis Meeting Notes
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---------------------------------------------
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(Notes by GH)
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Today: PionLT will be discussed first
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Present
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-------
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Regina - Garth Huber, Ali Usman, Muhammad Junaid, Alicia Postuma, Nacer Hamdi
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FIU - Pete Markowitz
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JLab - Dave Gaskell
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Ohio - Julie Roche
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Virginia - Richard Trotta
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CSULA - Konrad Aniol
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Junaid
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------
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PionLT Heep Studies
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- using global offsets presented last week
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- Data/MC ratios using Nathan's LH2 boiling factor
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- MM cut applied to exclude pi0, same cut value for all settings
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- R=0.89-1.020, average value ~0.95, which is MUCH better than earlier
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analysis
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- will have to apply Alicia's proton correction (~5%), and Nathan's final
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rate corrections (undetermined but will be small). With these applied, the
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ratios will be quite close to 1
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- Dave: intrigued by varying ratio for the three 6.395 GeV settings,
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variation from mean is about +/-0.05, which is much larger than the
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statistical error
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- we look at the setting kinematics, no obvious trend with anything
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- pHMS is not in saturation region
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- Dave: one Heep setting has evidence of a shift in HMS-delta between Data
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and MC (P_HMS=3.7 MeV, theta=31.6)
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- this might indicate that the swap in calculating offsets between
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theta_cent and P_cent is not quite right
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- we look at another setting to see if there's a consistent trend
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P_HMS=3.8 MeV, theta=29.7 setting showed no HMS-delta shift even though
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the setting kinematics are very similar
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- Garth: from everything he's seen, there appears to be a certain amount of
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non-reproducibility from one setting to another. For example, when
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returning the spectrometer magnets to a previous field, the currents
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usually differ by 1A or so from the previous value. It might be
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something along these lines
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- Dave: the beam energies are different between these two settings, and
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those are independent energy measurements, so that is a more likely
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source
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- Julie: we should take a look at the Heep setting with R=0.88
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- this shows no evidence of a shift, just a normalization difference
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- JM: will check if any bad runs were included by mistake
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- some discussion whether any further optimization is needed of Heep cuts
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- Dave: the difference between data and MC left of the W peak is due to
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mismodeling of resolution in SIMC. It's not experimental background and
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these events should not be removed as they're valid events
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Next steps:
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- started working on Q2=3.85, W=2.62 physics setting with 2 epsilon points
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- param files updated and pushed to GitHub
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Alicia
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------
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Discussion about BSA PLB updates
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- already started entering the article metadata in the journal server
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- created a Mendeley Data Repository for spreadsheets of numbers and other info
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that will be cited from the paper
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- planning to submit no later than Monday
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Nacer
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-----
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KaonLT Q2=0.5 analysis
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- working on t-binning, some jobs still running so no plots to show yet
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- some discussion about binning strategy
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- Richard: absolute minimum of 1000 events per t-bin, 2000 is better
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- Garth: it would be great if we could get 5 t-bins, no need for many more
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than this, it would be better to instead have more phi bins
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- will start with 10 phi bins
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Richard
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-------
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KaonLT Q2=4.4, W=2.74 LT-separation
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- did some checks to resolve the sigT<0 for lowest t-bin
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- found that this bin had significant pion contamination
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- raised lower limit of bin from 0.35 to 0.40 to remove pion background
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- as a result, sigT is closer to zero now for this bin
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- upper limit of this bin was unchanged at 0.85, will raise it higher as well
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so the bin has more statistics, and then will do some iterations
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- Garth: a bit surprised that the fit (red) curves for LT, TT don't go to zero
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as -t -> -tmin even though the functional form has sin(theta*) dependence
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- Richard: over the t-bins, theta*=22-31deg
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- Garth compares to 6 GeV data, where theta*=2-13deg
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- maybe it's a kinematic effect at the higher energy, but it's a bit
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surprising that theta* is so large for the lowest t-bin
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- Richard will check
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Next Meeting
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-------------
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- Thur Mar 13 @ 16:30 Eastern/14:30 Regina
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- KaonLT will go first
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- NOTE: on Mar 9 USA moves to DST, so we will need to move to 16:30
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Eastern/14:30 Regina for the period March 13-April 10
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- after that, we can return to 15:30 Eastern for the convenience of our USA
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colleagues
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