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): RefreshImprove mechanical accuracy of S-UTS stage Develop track reconstruction soft-ware

Satoru Takahashi (Doctor course student):DONUTRefreshGamma-ray telescope with Emulsion Chamber

Hirotaka Kubota (Doctor course student):RefreshFragmentation of heavy-ion Gold deposition development

Ryosuke Komatani (Muster course student):Develop online data process soft-ware

Our history

scan back

volume scanaround VTX prediction point

(~1cm*1cm*10plates)

VTX located

volume scanaround stop plate

(~1cm*1cm*6plates)

direct VTX hunting

VTX location method

scan back & volume scan

not foundVTX search

found

partner & parent search

276

ECC arrived

109

114

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

scanning40

waiting

127

finished

5

black CS

status table in Japan

+61 (5.Jan. arrived)

e-showerdown platesingle stop

PLdown-stream up-stream

CC

NC

ALL

Vertex plate(CC,NC)

ALL

DVH

SB

SB : Scan Back LocationDVH : Direct Vertex Hunting

Vertex plate(SB,DVH)

down-stream up-streamPL

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

Lock on decay search

xz-projection yz-projectionThis 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<=200m from vertex point.First we check real stop then look for parent or 2nd vertex. All young people rock on decay search.

vertex point 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 : 235646940Brick : 41517Type : CC

Now request next brick

Under analysis events

Maybe partner track make large angle.So it needs large angle scanning (tan ~ 1 ).

Event : 234787942Brick : 151760Type : CC

Under analysis events : e-showerEvent : 234787942Brick : 151760Type : CC

Under analysis events : e-shower

2

stop plate1~2

7

single stop

5

e-shower

14

volume scanunder analysis