Project

General

Profile

Kaon LT Meetings » mtg_23feb09.txt

Garth Huber, 02/10/2023 04:29 PM

 
1
                 Feb 9/23 PionLT/KaonLT Analysis Meeting Notes
2
                 ---------------------------------------------
3
                           (Notes by GH and SJDK)
4

    
5
                    Today: PionLT will be discussed first
6

    
7
Please remember to post your slides at:
8
https://redmine.jlab.org/projects/kltexp/wiki/Kaon_LT_Meetings
9

    
10
Present
11
-------
12
Regina - Stephen Kay, Ali Usman, Alicia Postuma, Nathan Heinrich, Garth Huber,
13
   Vijay Kumar, Muhammad Junaid, Love Preet
14
JLab - Dave Gaskell
15
CSULA - Konrad Aniol
16
CUA - Tanja Horn, Richard Trotta
17

    
18
Nathan Updates
19
--------------
20
Result of detector time and reference time cut analysis
21
- Q2 = 3.85, W = 2.62, Left, Low eps (LH2+), whole setting
22
   - With new cuts, fine ~200 more pions compared to online
23
   - ~2.5% more events (8261 vs 8070)
24
   - Distributons look slightly better, very subtle changes
25
- DG - Probably worth checking a setting with a poor real/random ratio
26
   - May see a more dramatic difference
27
   - Try a pi- run
28
   - Nathan has it, but no online plots for comparison
29
      - Q2 = 3.85, W= 2.62, low eps, left
30
      - https://logbooks.jlab.org/files/2022/09/4039344/Q3p85W2p62left_lowe_LD-_Pion_Analysis_Distributions.pdf
31
      - 4806 pions
32
      - Looks like we have less now
33
         - Could be that some runs were missed (setting was split in two)
34
         - Please do a more thorough comparison for a pi- run
35
         - REMEMBER: All data are guilty until proven innocent!
36

    
37
- Pushed changes to param files, std.kin
38
   - not everything is replayed yet
39
   - ref time cuts stable so this part should be okay now
40
   - Next step is Cherenkov calibs
41

    
42
Junaid Updates
43
--------------
44
Back from Pakistan
45
- Trying to catch up on classes/get back on track with analysis
46
- DC and calorimeter calibration is next step
47

    
48
Richard Updates
49
---------------
50
Changes to PM/EM calcs in SIMC
51
- For SIMC/hcana comparison, complicated doing it in SIMC
52
- Use a script to convert root file
53
   - Made this and ran it
54
   - Nothing looks different?
55
   - New variables look the same as the old ones
56
      - DG - Seems very strange
57
      - RT will meet with DG tomorrow about this
58

    
59
Weird Right setting from last week
60
- tightened up CoinTime cuts
61
- CT peaks slightly offset, will correct for at some point
62
- Dramatically imrpoved MM distributions
63
- Black is right, green centre, red left
64
   - Black looks much improved
65
   - Still a bit high, but now only by ~50% instead of 10x
66
   - -t distribution no longer going through 0
67
      - SK - Thought, we never plot 2D t vs anything other than phi
68
      - Could be interesting to check and remove junk events
69
      - t vs CT/RF?
70

    
71
- For black (right) CT dist, tails are being removed - real events removed
72
   - GH - Do we need to correct for this? Cutting real events?
73
   - DG - Is this a final cut or just a diagnostic?
74
      - In principle, spectra should look the same with tight cut or with
75
        random subtraction, not the same indicates a problem that needs to
76
        be investigated
77
        e.g. if peaks left/right of real peak are actual physics events from
78
        other process
79

    
80
- Still need to optimize PID cuts
81
   - only temporary cuts
82
   - will have to investigate where e-pi, e-p coins are compared to e-K and
83
     adjust cuts accordingly
84

    
85
- Maybe cuts not being applied correctly for right setting?
86
   - Something is clearly dramatically different for the right setting
87
   - GH: Right setting probably has high SHMS rates, at very forward angle
88
     Please *look up* running conditions of right setting comp to cent, left
89

    
90
Ali Updates
91
-----------
92
HMS Cherenkov and calorimeter efficiency study
93
- slide nicely lists ALL cuts applied
94
- Wide range of kinematics investigated in KaonLT data
95
- Run 4871: 
96
   - Cherenkov efficiency is very low (94.82%)
97
   - Cal eff=98.66%
98
- Run 4919:
99
   - Cher eff=93.96%
100
   -  Calorimeter efficiency v.low (90.75%)
101
   - A lot of pi- contamination present, not a good setting for efficiency study
102
- Run 4987:
103
   - Cherenkov efficiency ~97.15%
104
   - Cal 98.93% - Calorimeter a little low?
105
- Run 5222:
106
   - Cherenkov 96.16%, calorimeter 99.18%
107
   - DG: this looks like a classic case of FADC-DT effect due to HMS-Cer light
108
     leak
109
     This is a *real effect* that will have to be included in efficiency
110
     The complication is that this FADC-DT is in priciple rate dependent and it
111
     may be tricky to separate out the rate dependence from other inefficient
112
     effects
113

    
114
   - Looks like we have a light leak in the Autumn 2018 data
115
   - Could've been introduced when the HMS mirror was fixed
116
   - Will be there for *all* KaonLT data and Summer 2019 PionLT data, so Vijay
117
     needs to be careful about this in low Q2 analysis as well
118

    
119
Spring 2019 data efficiencies
120
- Run 7909:
121
   - 75.71% Cherenkov efficiency, 96.98% calorimeter efficiency
122
   - Low total efficiency in low epsilon data - it's all the pions!
123
- Run 7979:
124
   - Cer 94.92%, cal 99.09%
125
   - Calorimeter efficiency is pretty good
126
   - DG: I would expect a cal eff closer to 99.5%
127
   - AU: will try applying a neutron MM cut to further clean the sample,
128
     expecting a further increase of 0.5%, i.e. closer to what DG expects
129
- Run 8255:
130
   - Cer 71.66%, Cal 95.58%
131
   - low stats in a single run, this is high Q2 low epsilon
132
   - need to add more runs to get better #events
133

    
134
- DG - Suggest to Look at HeeP singles to get a handle on these efficiencies
135
   - Cut tightly on W2 dist, eliminate pions
136
      - Should have a nice clean sample
137
   - GH - Hopefully singles fill more of the focal plane than HeepCoin
138
   - Most of the physics settings it's hard to get a usable efficiency number
139
     due to pi- contamination in HMS
140
   - GH - Focus on 1-2 settings that look promising, otherwise, focus on the HeeP
141
      - Don't do a run by run efficiency, just use result from HeeP to guide this
142

    
143
Vijay Updates
144
-------------
145
Analysing Summer 2019 Q2=0.38 data with 3 epsilon settings
146
   - fixed issue with cut file, weird random peak to left of prompt peak is gone
147
   - Can probably take a lot more peaks on each side of the prompt peak for
148
     random subtraction
149
      - At least 2 more on each side
150

    
151
- Diamond cut implemented, needs some small adjustment on top edge in
152
  comparison to low epsilon data
153

    
154
- Still finalising t-binning
155
   - ~ 45k events per bin (summed over all SHMS angles and epsilon)
156
   - 8 t bins
157
   - GH for first t bin, should move left edge of the bin closer to the data
158
      - For low Q2 FF test, the dependence at low -t is crucial
159
      - Should go very narrow on binning at low -t
160
     - Could go up to 10 bins
161
   - DG - What is the -t resolution?
162
      - Can't bin finer than this or t0bin migration will be a big issue
163
      - GH will discuss with VK how to get this info from SIMC
164

    
165
Alicia Updates
166
--------------
167
- Assignments/presentation updates
168
- No new updates, will have something after WNPPC
169

    
170
Next Meeting
171
------------
172
Thur Feb 16 @ 17:00 Eastern/16:00 Regina/15:00 Mtn/14:00 Pacific
173
- KaonLT will go first
174
- SK, NH, GH, AP, LP will connect from our hotel room in Banff
175
- GH, AP, LP might be a bit late
(168-168/443)