## Kaon LT Meetings » mtg_24apr25.txt

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Apr 25/24 PionLT/KaonLT Analysis Meeting Notes |
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(Notes by GH) |

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Today: KaonLT will be discussed first |

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Please remember to post your slides at: |

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https://redmine.jlab.org/projects/kltexp/wiki/Kaon_LT_Meetings |

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Present |

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Regina - Garth Huber, Nacer Hamdi, Ali Usman, Alicia Postuma, Muhammad Junaid, |

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Nathan Heinrich, Vijay Kumar |

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York - Stephen Kay |

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JLab - Dave Gaskell |

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CSULA - Konrad Aniol |

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CUA - Tanja Horn |

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Vijay Kumar |

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Initial results of Low Q2 PionLT L/T-separations |

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- changed formula for sigT to a+b*(-t) type form for now |

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- fits now converge, was able to do several iterations |

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- comparisons between Data and MC distributions look reasonably good |

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- should change lower MM cut to ~0.91, or remove entirely, to avoid |

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correction for events lost due to the cut |

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- Exp/MC ratios are approximately 1, but with some phi-dependence for some |

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t-bins |

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- GH and Vijay will need to look more closely at these, with the aim of |

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making the ratios more flat vs phi |

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- likely will have to modify the sigT equation to get a better fit, need a |

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close look to see what to do |

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- possibly the LT, TT equations will also need modification |

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- sig_UNS phi distributions looking better than before, the phi distribution is |

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getting more consistent between low, mid, high-epsilon |

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- these will hopefully improve further once the ratios are more flat vs phi |

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- initial L/T/LT/TT cross sections |

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- sigLT has a trend to values closer to zero as -t decreases, but the |

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smallest -t bin does not have the smallest magnitude, this will need |

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investigating |

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- the t-dependence of sigL also will need confirmation, likely it will change |

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as the iterations continue |

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- showing results at weekly meetings in order to gain feedback is important, |

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we are willing to have Vijay go first for the next few meetings, if this is |

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helpful to him |

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Ali |

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--- |

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- recon_hcana was using wrong mass, gave weird phi-distributions |

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- this has now been fixed |

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- unfortunately, all SIMC needed to be re-run, as old files were deleted |

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Alicia |

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BSA systematic uncertainties |

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- A=full fit, A'=simple fit, typically A<A' |

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- quoting A as final value, with syst_fit=|A-A'| |

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- showing this as a +/-systematic over-estimates the uncertainty, as the real |

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value presumably is between A and A' |

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- agreed that we will show syst_fit as an asymmetric error |

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- will not be present next week due to other obligation, hoping to give an |

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update on the BSA paper in 2 weeks |

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Nacer |

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KaonLT Low Q2 PID efficiency systematics checks |

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- recap of Ali's 2023 slides where HMS_cal and HMS_cer efficiencies were found |

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using Heep runs |

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- runs 6600, 6603 were from this data set |

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- used only 2-4 GeV/c runs to avoid pi- Cherenkov radiation |

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- for CAL_eff, placed tigher cuts on CER, and vice versa |

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- small rate dep was seen in CER_eff, Ali took the average, and found a |

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systematic from the RMS deviation |

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Nathan |

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PionLT BCM calib |

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- met w/Dave Mack this morning to discuss Nathan's initial results |

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- DM thinks a combined fit using runs w/same config can eventually be used |

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- suggested that Nathan look at BCM1,2 and throw away runs>50uA due to |

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small non-linearity |

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- will check how stable the parames are before doing a combined fit |

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- DaveM's main concern from Nathan's Lumi work so far is that the found 170nA |

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offset is too large, was expecting an offset closer to 70nA based on prior |

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experience |

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- will recheck the offset after calibs complete |

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- Nathan will write a README on the changes to the calib code after complete |

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Junaid |

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- finding his experience @ JLab to be very valuable |

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Next Meeting |

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- Thur May 2 @ 15:00 Eastern/13:00 Regina |

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- PionLT will go first |

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