Yup, sorry about that. The label on the x-axis is wrong it should read "M(K+K-)" and as the filename indicates it is the invariant mass of the K+K- where the K- was obtained through missing mass (and kinematically fit) -- So it really is the missing mass off the proton, but now its semantics since those are equal after the kinematic fit. Anyways, I updated the figure with the statistics I got over night and attached it.<br>
<br>This data represents about 50% of g12 and exactly 354 complete runs where I have cut out the "tripped" regions which were not included in the flux calculation. I am in the process of getting the rest of the data now. If you don't care about the flux for this analysis, I can get you 95% of the data by tomorrow I think.<br>
<br>As far as basic cuts, here they are:<br>1. I require "complete" information from the track fitter. Specifically, the TDPL bank had to have positions and local angles for the planes at the start counter and time-of-flight counters.<br>
2. The start counter and TOF hit had to be associated with the track _during_ the reconstruction. I.e., the ST and TOF hit shows up in the TBID bank.<br>3. vertex timing cuts are as such for each detected particle (in this case, the proton and the K+):<br>
dt_vtx_pid = t_vtx(TAG) - t_vtx(TOF, Beta_momentum[PID})<br> dt_vtx_st = t_vtx(TAG) - t_vtx(ST,TOF)<br>where t_vtx(TAG) is the vertex time according to the tagger hit, t_vtx(TOF, Beta_momentum[PID}) is the vertex time according to the TOF where I got beta from the particle ID and the momentum in the DC, and t_vtx(ST,TOF) is the vertex time according to the hits in the ST and TOF. The path lengths were obtained from the TDPL bank in the latter two.<br>
4. There was a mass cut on both the proton and K+:<br> abs(M_measured - M_book) < M_cut<br>where M_cut is 62.4 MeV for the proton and 60 MeV for the K+<br>5. There were a few tagger timing cuts as well:<br> abs(t_tag - t_pho(PID)) < 1<br>
abs(t_tag - t_pho(ST,TOF) < 1<br>where t_tag is the RF corrected tagger time for the selected tagger hit, and t_pho(PID) and t_pho(ST,TOF)) are the tagger times in a similar vein as the vertex times of cut #3 above.<br>
6. There was a cut on the missing mass off the proton and K+ (around the K-):<br> abs(M_Km_measured - M_Km_book) < M_Km_measured<br>7. the minimum probability after the kinematic fit (pK+ to a missing K-) was 0.01 (equivalently, 1%).<br>
<br>I am including plots which illustrate all but the last two cuts in my analysis note on cascades since they are (slightly) different from what I used in my dissertation. The cuts 1-5 (where the K+ is concerned) are part of the skim I made so changing them would take a long time (month or so). Cuts 1-5 for the proton or cuts 6 and 7 can be changed in a day but I think they should be broad enough for any analysis, especially since the resulting four-vectors are post-kinematic fit.<br>
<br>It occurred to me you may need the vertex positions of the proton and K+. Let me know if you do and I can redo the ntuple.<br><br><div class="gmail_quote">On Wed, Nov 2, 2011 at 8:48 PM, Alex Kubarovsky <<a href="mailto:kubarovsky@gmail.com">kubarovsky@gmail.com</a>> wrote:<br>
<blockquote class="gmail_quote">Dear Johann,<div><br></div><div>I think the picture you attached is missing mass to proton with K+ detected, am I wrong?</div>
<div><br></div><div>Thank you, Alex<br><br><div class="gmail_quote"><div><div class="h5">On Wed, Nov 2, 2011 at 4:24 PM, Johann Goetz <<a href="mailto:jgoetz@ucla.edu">jgoetz@ucla.edu</a>> wrote:<br>
</div></div><blockquote class="gmail_quote"><div><div class="h5">Hi all,<br>I was not sure who to send this to so I sent it to the g12 mailing list. I am outputting a small ntuple of proton K+ events where I have kinematically fit to a missing K- with a probability selection of >1%. I have briefly looked at the data to make sure the numbers are reasonable (see phi(1020) peak attached). <br>
<br>I am copying the files here:<br> /volatile/clas/clasg12/goetz/pkp_km_kfit_ntuple<br><br>The files I have processed so far are __complete_runs__ meaning that every event was considered in the given run. e.g. the file kaon.good.56363.txt includes all data from run 56363 ("good" here means non-trip regions). These are plain-text files and the first two lines are header information: first line is column label and the second line is column type: i4 = int, f4 = float.<br>
<br>I included the run and event number, the beam energy (ebeam) and the four-momenta of the three particles p, kp, and km. The other columns are the results from the kinematic fit. The one you might want to look at is "kfitprob". I made a selection on this variable at >1%, but you might want to first increase this to 10% if you find you have any background you can't explain.<br>
<br>>head -3 kaon.good.56363.txt <br>run event kfitprob kfitchi2 kfitpull_ebeam kfitpull_p_mom kfitpull_p_lam kfitpull_p_phi kfitpull_kp_mom kfitpull_kp_lam kfitpull_kp_phi kfiterr_km_mom kfiterr_km_lam kfiterr_km_phi ebeam p_e p_px p_py p_pz kp_e kp_px kp_py kp_pz km_e km_px km_py km_pz<br>
i4 i4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4<br>56363 40481 0.619477 0.246603 -0.507221 0.367299 0.49034 -0.507834 0.513646 -0.477136 0.501621 0.018267 0.0236273 0.0236293 2.9719 1.12352 -0.0508986 -0.243942 0.565551 1.80493 0.366565 0.431194 1.64126 0.981723 -0.315666 -0.187252 0.765084<br>
...<br clear="all"><font color="#888888"><br>-- <br><a href="http://sites.google.com/site/theodoregoetz/">Johann T. Goetz, PhD.</a><br><a href="mailto:jgoetz@ucla.edu">jgoetz@ucla.edu</a><br>
Nefkens Group, UCLA Dept. of Physics & Astronomy<br>
Hall-B, Jefferson Lab, Newport News, VA<br>
Office: <a href="tel:757-269-5465">757-269-5465</a> (CEBAF Center F-335)<br>Mobile: <a href="tel:757-768-9999">757-768-9999</a><br><br>
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<br></div></blockquote></div><br></div>
</blockquote></div><br><br clear="all"><br>-- <br><a href="http://sites.google.com/site/theodoregoetz/">Johann T. Goetz, PhD.</a><br><a href="mailto:jgoetz@ucla.edu">jgoetz@ucla.edu</a><br>
Nefkens Group, UCLA Dept. of Physics & Astronomy<br>Hall-B, Jefferson Lab, Newport News, VA<br>
Office: 757-269-5465 (CEBAF Center F-335)<br>Mobile: 757-768-9999<br><br>