Vertex location status of Japan Nagoya vertex hunting team Y.Nonoyama, K.Hamada, S.Takahashi, H.Kubota, R.Komatani 2009 Jan 22 OPERA Japan Meeting

Yoshiaki Nonoyama (Doctor course student): Refresh (set up Temp and Humi monitor system) PEANUT Kaname Hamada (Doctor course student): Refresh Improve mechanical accuracy of S-UTS stage Develop track reconstruction soft-ware Satoru Takahashi (Doctor course student): DONUT Refresh Gamma-ray telescope with Emulsion Chamber Hirotaka Kubota (Doctor course student): Refresh Fragmentation of heavy-ion Gold deposition development Ryosuke Komatani (Muster course student): Develop online data process soft-ware Our history

scan back volume scan around VTX prediction point (~1cm*1cm*10plates) VTX located volume scan around stop plate (~1cm*1cm*6plates) direct VTX hunting VTX location method scan back & volume scan not found VTX search found partner & parent search

276 ECC arrived in progress VTX located 21 re-glycerin, wait sheeting 19 CS 42 CS->ECC 0 scan back 62 volume scan 14 under analysis 22.Dec. arrived 13 another brick 14 under analysis 38 scanning 10 black ECC 28 scanning 40 waiting 127 finished 5 black CS status table in Japan +61 (5.Jan. arrived) e-shower down plate single stop

PL down-streamup-stream CC NC ALL Vertex plate(CC,NC)

ALL DVH SB SB : Scan Back Location DVH : Direct Vertex Hunting Vertex plate(SB,DVH) down-streamup-stream PL

Vertex position distribution(all plate) X(mm) Y(mm)

Number of shower tracks/interaction ALL CC NC Mean = 3.4 tracks N tracks

Angle distribution of shower tracks  x(rad) yy

Lock on decay search xz-projectionyz-projection This is “decay search sheet”. Vertex plate and down 2~3plate is most important plate(decay trigger plate). These tracks are corrected by less than IP<=200  m from vertex point. First we check real stop then look for parent or 2 nd vertex. All young people rock on decay search. vertex point Check track exist or not. (data and eyes) If stop then look for parent or partner between 1mm of lead

Summary We located 114 interactions out of 276 ECCs. Under analysis events for vertex confirm are “stop down plate”, “e-shower” and “single stop”. About stop down plate events, maybe scan-backed low-energy track. About e-shower events, it should be scan up plates. About single-stop events, it should be parent search and confirm real stop by eyes. We start decay search. A decay candidate is found. But very preliminary. This event stopped PL3, so now request down-stream ECC. Up to next meeting we can show final result about this event.

Back up

Event : Brick : Type : CC Now request next brick

Under analysis events Maybe partner track make large angle. So it needs large angle scanning (tan  ~ 1 ).   Event : Brick : Type : CC

Under analysis events : e-shower Event : Brick : Type : CC

Under analysis events : e-shower

2 stop plate1~2 7 single stop 5 e-shower 14 volume scan under analysis