Kaon_LT Experiment

{{>toc}}

h1. *Kaon LT Meetings*

----

h2. February 22, 2018

*Links to talks->* "Andres":https://redmine.jlab.org/documents/19

*  Discussion of Andres' slides on elastic W calculation in hcana - initial issue with negative W values seems to be due to outdated information in standard.kinematics file. Additional investigation ongoing.

* Brief description of Samip's work - working on coincidence timing decoding with JLab staff and re-optimization of kinematics

* Discussion of Richard's slides on run plan kinematics and preparations -

** everyone agrees that in general want to have as many L/T cross section separations as possible in a robust run plan balancing statistics vs. systematics

** before actual run may want to do a 3D optimization in all kinematic variables to get the best possible delta(epsilon) for the L/T separations

** for each setting will need 1-2 shifts for calibrations - need to negotiate with other experiments in run group

** kinematics plots W-Q2 show that still need to do some optimization

** run sheets: include raster size, update coincidence count labeling, and carbon target labeling

* Discussion of next meeting. Garth at JLab 8-16 March - might have meeting during that time.

* *Action Items:*

** Post slides/notes from this meeting and procedure to set up hcana in Redmine (Tanja)

** Update run sheet and kinematic optimization for W/Q2 (Garth)

** Circulate elastic calculations for kinematic settings (Samip)

** Continue investigation of elastic data and run plan kinematics (Andres/Richard)

** Test software installation instructions (Pete)

** Draft email to JLab management about need for small angle beam pipe - need to have HMS minimum angle of less than 13 degrees for kaon L/T separations (Tanja) 

----

h2. March 29, 2018

*Links to talks->* "Richard, ":https://redmine.jlab.org/documents/16 "Samip":https://redmine.jlab.org/documents/27

* Details of adding points to fall run plan - will be ready sooner, likely in week of 4/1 (Garth, Samip, Tanja)

* Luminosity scans (Ryan, Andres, Richard, Pete)

* Macros, SIDIS analysis (Hem, Anashe)

* Elastic data (TBD)

----

h2. April 26, 2018

*Links to talks->* "Richard,":https://redmine.jlab.org/documents/18 "Ryan, ":https://redmine.jlab.org/documents/20 "Samip":https://redmine.jlab.org/documents/25

* Discussion luminosity scan analysis (earlier scan) - Richard

** Shown is a scaler-based analysis using scalers from report file and from ROOT tree - the values are different, why that is has to be checked

** Notes on efficiencies in report file:

*** DT (EDTM) is not electronic deadtime. Instead use for now 50ns* trigger rate for HMS and 100ns* trigger rate for SHMS

*** Cherenkov efficiency seems low (check if that is due to PID, thresholds, pi/e, etc)

*** Tracking efficiency needs to be checked

*** 3/4 trigger efficiency seems ok

* Discussion luminosity scan analysis (later scan) - Ryan

** Fewer carbon runs than earlier scan

** Shown is a tracking-based analysis using data from the ROOT trees

** First results for carbon, LH2, and LD2, but efficiencies need to be checked

* SIDIS analysis - Hem

** Shown is a data/MC comparison for different kinematic settings. Agreement in shape is very good. Normalization has yet to be applied.

** Discussion about agreement in z and apparent offset - relation of this offset with spectrometer offset

* Analysis of exclusive events in SIDIS - Samip

** Shown is a look at the first kaon events in exclusive limit of SIDIS data

** Ongoing work on implementing coincidence time into tree

* Discussion of run plan, and in particular possible low Q2/low energy

** Assume that kaon low Q2=0.4 already included - have kinematics with specified beam energies, if needed

** For pion form factor and LT, have two possible settings that can use the prescribed beam energies: Q2=1.45 and 0.35 GeV2 - prioritize towards the higher Q2 as not as sensitive to offsets

** Garth will put this together in a draft email

----

h2. May 10, 2018

*Links to talks->* "Hem":https://redmine.jlab.org/documents/24, "Richard":https://redmine.jlab.org/documents/23, "Ryan, ":https://redmine.jlab.org/documents/20 "Samip":https://redmine.jlab.org/documents/26

* Luminosity Scans January 2018 (Richard)

** Tracking-based analysis for Runs 1415-1423, .. for now focus on HMS, typical HMS S1X rates are <

** Cuts applied: PID for electrons (Cer, Cal), acceptance (delta)

** Efficiency calculation was investigated in detail and applied using scalers from trees

** Results for carbon (normalized to 30uA) show large variation - need to understand

** *Next steps:*

*** Double check calculation of computer lifetime, look for differences in TRIG and PRETRIG scalers

*** Check stability of pre-scale (Ryan saw changes within runs)

*** Check if detector calibrations for runs are implemented correctly

*** Analyze with Ryan's cuts

* Luminosity Scans April 2018 (Ryan)

** Confirms Richard's earlier finding that scaler-based analysis is not reliable and that it's best to analyze event-by-event

** Tracking-based analysis for runs 2073-2095

** Cuts applied: PID for electrons (TOF, Cal, Chi2), acceptance (delta and angles), BCM4a

** Included most recent detector calibrations in replay of these runs

** Efficiencies from report file mainly, may need to update tracking efficiency implementation

** Found that calculations of computer deadtime requires different set of scalers for runs from January to those from April 2018

** Results show carbon yields consistent with unity within error (0.5% error bars), and boiling for hydrogen and deuterium

** *Next steps:*

*** Check tracking efficiency

* *Global comments on Luminosity Scans (so far)*

** April 2018 scans show hydrogen and deuterium target boiling on level of 3-4%, Carbon is consistent with no boiling, as expected - based on description, new targets are expected to have less boiling than those used previously, e.g. in FPI2. Double check this.

** Efficiencies in report files need to be updated, e.g. CPU deadtime (Richard)

** Check if BCM4a is the one closest to the target - get a map of the hall (Richard, Ryan)

** Uncertainties on current

** Detector calibrations

** HMS vs. SHMS

* eK+ coincidence time from SIDIS Spring 2018 run (Samip)

** Worked with Mark Jones on coincidence time calculation - now available in hcana (see Samip's 10 May 2018 email for more details)

** runs used in this analysis: 3423 with Q2=3.1 GeV2 and W=2.78 GeV

** Coincidence time spectrum shows peak separations >2 ns corresponding to different accelerator frequency

** Missing mass spectra: Kaon peak clearly visible, also see pions even after cuts

** Found that pions appear localized in phase space - seems to be due to end point in kinematic phase space

** *Next steps:*

*** Look for a run with kaon momentum closer to 3 GeV/c (aerogel threshold is ~3 GeV/c for kaons for n=1.015)

* Yield normalized ratios from SIDIS (Hem)

** Yield ratios of data to MC match well in shape, but normalization seems not quite right

** *Next steps:*

*** Check if efficiencies, currents, run time etc. are taken into account correctly

----

h2. May 17, 2018 

*Links to talks->* "Richard":https://redmine.jlab.org/documents/29, "Ryan":https://hallcweb.jlab.org/DocDB/0009/000968/001/Presentation.pdf, "Samip":https://redmine.jlab.org/documents/30

* Luminosity scans (Richard, Ryan)

** Carbon scan from April seems consistent with no boiling, LH2 and LD2 show deviation from unity, should check effect of EDTM events on efficiencies

** Carbon scans from January (low rates) have large deviations from unity, in particular behavior at higher currents (>40uA), e.g. cpu dead time, that is not yet understood

** discussion about pre-scale factors

* Discussion about Richard's script extracting and printing information from report files and trees including histograms

** Add option for looking at yields with cuts on cointime, target window, and missing mass

** Add option to look at real peak vs. background level

* H(e,e'p) kinematics investigation for fall run (Samip)

** Optimal range is between electron angles of 17-20 degrees, time required ranges from ~1 hour at 17 degrees to ~3 hour at 20 degrees, other angles may be of interest for disentangling charge and current dependent effects

* *Action Items*

** Luminosity scans at low rates from January (Richard)

** Luminosity scans from April with corrected efficiencies, e.d. DT (Ryan)

** H(e,e'p) and H(e,e') kinematics for upcoming Kaon LT run (Samip)

** Kaon LT detailed run plan (Garth, Pete, Tanja)

** Preparations, e.g. report files, diagnostic histograms and real time monitoring, shift worker instructions, optimization of trees (all)

----

h2. May 31, 2018

*Links to talks->* "Samip":https://redmine.jlab.org/documents/30

h2. June 28, 2018

*Links to talks->* "Richard":https://redmine.jlab.org/documents/34

* Ryan 

** resolving differences between his analysis and Richard's

* Richard

** Discussed with Mark Jones and is cross checking his January luminosity scan analysis against Mark's. Realized that BCM calibrations (gains, offsets etc) are different - currently working on fixing that, presents current results - low curent point is ~10% below unity, discussion that this seems to indicate that BCM offsets are the issue as low current points would be most sensitive, is planning to also double-check the BCM calibration procedure - had discussion with Dave Mack at JLab

** Presents a script developed for luminosity scans that determines yields for a run number input on command line. Discussion this could be good to adapt for kaon counting during experiment.

----

h2. July 11, 2018

*Ongoing Tasks->* #381 #382 #383 #384

----