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TPC meeting 2004Jun04. status of experiment. Another 2 scinti. has been installed to cover forward acceptance, called as forward left & right. The vertical gap between forward up & down was increased. The coverage is 6 ~ 7 layers hit. Re-alignment on 20 th June.
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TPC meeting 2004Jun04 status of experiment Another 2 scinti. has been installed to cover forward acceptance, called as forward left & right. The vertical gap between forward up & down was increased. The coverage is 6 ~7 layers hit. Re-alignment on 20th June. The magnetic shield for AC PMTs was moved off from tracking area. → caused gain drop. We need to study the position dependence again. This is very time consuming. Study while beam-line tuning (not user time) is desirable. Pre-scale 2charge trigger by factor of 3. Totally 47Hz request 35Hz accept @420k tagger. The arrival of new laser tube is delaying.
Beam time schedule • In June and July, we have 102 shifts. We spent most of time to trigger study. But still AC doesn’t have enough efficiency (98%) and Imai-san is proposing to install small veto counter, 20mmФ at AC. • CH2, C and Cu target will be used and share # of triggers by 2 : 1 : 1 . The most important thing is to estimate # of Λ(1405) from real data • As detection of Λ is easer than Σ. We will look for , assuming same production cross-section as Λ(1405) • Detection of Λ is urgent. From September, 2.9GeV beam will be available. We may need to think about it.
re-solve RF in LEPSana Targ SC TOF between target & SC causes miss-ID of RF Miss-ID of RF
procedure Solve mass of particle by TOF between SC and TOF. Select fastest particle if ntrk>1. Get beta. At TrackVertex.F call findRfAgain.c giving beta and path-length from target and SC as arguments. Find RF again after correction of TOF from target to SC. And correct TOF from target to TOF-wall Re-calculate mass in TrackVertex.F New ntuple variables dTTarST (dTTarget2STA) slengSTA (path-length from SC to TOF) (uncorrected TOF, RF, mass will be included)
After RF correction There still exist miss-ID bands. Further study necessary. sleng – slengSTA (mm) dTTarg2STA (nS) TOF (nS), ntrk=1
Runge Kutta tracking Uchida-san made nice frame-work for the study based on the analyzer of En’yo-san’s Ф experiment. Niiyama is improving it. In current version residual is calculated when a track cross the pad layer. Tracking get stacked when 2 hits found in one layer. → Tracking based on arcLength Improve the formula to calculate residual Field map Linear approximation to calcurate residual is not good for low pt particles. circle approx. Runge-Kutta step measured point pad layer
display runge-kutta tracking XY XZ White : measured Black : traced point by RK YZ
Residuals assuming uniform field residual Z layer 6 residual X layer 6 residual Z layer 10 mm mm