OPERA 実験の解析 「フレーバー物理の新展開」研究会 佐藤 修 名古屋大

CERN to Gran Sasso, neutrino beam Gran Sasso 地下研究所 CERN SPS 730km

OPERA ECC Brick Lead plate(1mm) / Emulsion Film (OPERA film) Sandwich 125mm 100mm Lead Plate Emuslion Film (OPERA Film) 125mm 100mm Pb Emulsion layers  1 mm

Expected Event Yield m2m2 1.9 x eV x eV x eV 2 B.G. Final Design ν μ CC ν μ NC 7075 ν μ CC 494 ν e CC 188 ν e CC 17 Clear ν τ CC events ν μ ν e Interaction Full mixing, 5 years 4.5 x pot / year Target Mass :1700 ton

5 OPERA is an International Collaboration 37 INSTITUTIONS, ~160 PHYSICISTS IPNL, IRES, LAPP INR ITEP JINR, Obninsk Zagreb L’Aquila, Bari, Bologna, Napoli, Padova, Roma, Salerno, LNF, LNGS Bern Neuchatel Zurich Brussels Hamburg, Münster, Rostock Sofia Aichi, Toho Kobe, Nagoya Utsunomiya Technion Haifa METU Ankara IHEP Beijing Shandong Gyeongsang University

6 37 INSTITUTIONS, ~160 PHYSICISTS IPNL, IRES, LAPP INR ITEP JINR, Obninsk Zagreb L’Aquila, Bari, Bologna, Napoli, Padova, Roma, Salerno, LNF, LNGS Bern Neuchatel Zurich Brussels Hamburg, Münster, Rostock Sofia Aichi, Toho Kobe, Nagoya Utsunomiya Technion Haifa METU Ankara IHEP Beijing Shandong Gyeongsang University OPERA is an International Collaboration

VETO Muon spectrometer Target Wall ECC & CS & TT HPT Magnet & RPC Super module 1Super module 2 neutrino

~200k ECC bricks ECC Weight ～ 1700ton 64×52ECC/Wall Total 62 Walls

Wall ECC

現在 94,000 個のインストールが終了（最終の 61 ％） 2008 年 6 月までに生産完了予定

11 Detector filling Remember what was the situation one year ago ! Warmest congratulations to the teams involved: Brick components (Lead & CSd), BAM & BMS Coordinated in a Kaisen way by Salvatore June 10 th July 28 th October 25 th Achieved ! Including 15% contingency (~3 weeks) ‏

2007 年ニュートリノビーム照射 ９月末よりビーム照射。 計 8.24e17 pot （通常のビーム強度にて 2 日分） ECC ターゲットに３８ニュートリノ反応。 発生順に日本・ヨーロッパ－で分配。 日本 １９反応 ヨーロッパ－ １９反応

Integrated intensity 6.72 E 17 pot Fri 5/10 18:00 Tue 9/10 18:00 Commissioning Physics 3.91 E 16 pot 4 days of physics run, On average 1.58 E17 pot/day 8.24 E 17 pot Sat 20/10 Problems with controls Fri 12/10 Problems with controls

日本での初イベント検出＠ ECC のタイムテーブ ル。 Oct 16 Films (CSd +ECC) arrival by FEDEX 11:00 CSd films Room humidity about 2 hours Start CSd scanning 13:30 Every one CSd set takes about 2 hour For CC-like events CSd for NC-like events takes 12 hours All first trial of CSd scanning was finished. Nagoya 1 st event ( ,Brick33540) was found on CSd 17:00 Making ECC sheet for ScanBack around 21:00 (around Scan meeting) Start SB scan and stopped 56pl from downstream. Midnight (Works need to be confirmed.) Oct 17 Nagoya 2 nd event ( ,Brick20122 ) was found on CSd 11:00 Making ECC sheet for Scan back for 2 nd event) 15:00 Start SB scan 16:00 The SB stopped 10pl from downstream 17:00 Vertex was confirmed with 4 partner tracks ! 25:50

Event Brick#20122 pl10 Vertex confirmed with 4 partner tracks Nagoya 1 st Located neutrino Event Vertex confirmed Oct-18 01:50 am

theta_x (rad) theta_y (rad) IP (micron) VTx (micron) VTy (micron ) VTz (micron ) ScanBackTrk Partner Partner Partner Partner Found VTX information Event Brick#20122 pl10 All partner Trks are confirmed by Manual check.

ヨーロッパでの初イベント検出＠ ECC のタイムテーブル Event history from film development to event reconstruction… CS film developmentWed., Oct. 10 th Brick film development Thurs., Oct. 11 th CS scanning Fri., Oct. 12 th Brick transportation LNGS  BARISat., Oct. 13 th, 1.30 p.m. CS scanning predictions LNGS  BARISat., Oct. 13 th, 2.52 p.m. SB started Sun., Oct. 14 th, a.m. Track disappearance Sun., Oct. 14 th, 5.25 p.m. Quasi-online reconstruction Sun., Oct. 14 th, 5.42 p.m. and event confirmation

Main muon Mu GeV/c 2 highest probability bricks: Wall 25, Tray 46, Cell 23 Wall 25, Tray 46, Cell 22 di-muon candidate brick 53706

ニュートリノ反応解析手順 ニュートリノ反応が起きる。 1. ニュートリノ反応点探し 1.ECC(+CS) の取り出し。 2.CS の大面積スキャン。 3.CS の飛跡を ECC 中でスキャン。 4. ニュートリノ反応点特定 2. ニュートリノ反応点解析 1. ニュートリノ反応点周りのデータ取り。 2. 崩壊探索等、幾何学的分析。 3. 粒子識別、運動量測定。 4.ν τ か否か！

Event Brick#20122 pl10 Vertex confirmed with 4 partner tracks Nagoya 1 st Located neutrino Event Vertex confirmed Oct-18 01:50 am

~200k ECC bricks ECC Weight ～ 1700ton 64×52ECC/Wall Total 62 Walls

Brick Manipulator System (BMS, LAPP France)

Film と鉛板を交互に重ねた構造 ECC 総数 約 20 万個 –OPERA film 1200 万枚 ν イベント数 –(30 event/day)‏ ν τ 10~15 event OPERA Film × 57 plates Lead x 56 plates OPERA Film Lead plate 1mm 0.3mm 103mm 128mm 79mm ECC CS neutrino

CS Very low bg emulsion ECC brick １０ｃｍ 2.6 ｃｍ Target Tracker ECC Target tracker Basic unit of Detector x 200,000 ECC CS

TTCS ECC Large area scan ~100cm 2 Point Scan ~100x100m 2 Vertex location procedure Lead emulsion Lead emulsion Lead emulsion Lead emulsion Lead emulsion Lead emulsion Lead emulsion neutrino

S-UTS data flow. Raw data Data Base 150~ 300MB/s 2~10MB/s High speed Camera 3,000 frame/s Front end image processor 0 suppression, pixel packing Track recognition DAQ Pipe line processing Noise rejection Vertex reconstruction 2~10MB/s ~0.1MB/s USERs 1.3GB/s

角度精度 ： 15 mrad 位置精度 ： 0.9 micron 10cm 12.5cm Total ~100,000,000 tracks

Film 2 枚＝４乳剤層でノイズころし。 600micron 160micron X Z side view

Event Brick#33479 full area scanning (2008/feb/08 manual check)

Event Brick#33479 full area scanning 33479

Ev Brick#53486

Ev Brick#53486 Ev Brick#53486

SUTS Scanning Log full area scan of 500 OPERA films 2008/01/ /05/15 Black : SUTS01 Blue : SUTS02 Red : SUTS03

TTCS ECC Large area scan ~100cm 2 Point Scan ~100x100m 2 Vertex location procedure Lead emulsion Lead emulsion Lead emulsion Lead emulsion Lead emulsion Lead emulsion Lead emulsion neutrino

Plate Changer Brick Sheet

Volume Scan Volume Scan Area is 1cm x 1cm from VTX point. Scanning 5plates upper VTX Plate and 10plates below VTX Plate. VTX Plate 5plates 10plates

イベント紹介

23.2 GeV/c 2470 tot pe mu pe Ev Brick#20122

Scanback track (CS track)‏ Cosmic ray tracks for the alignment Plate Event Brick20122 Stop at plate 10 X projection Scanning area ν beam Lead 1mm Emulsion film 0.3mm

X projection Z projection Scanback(μ)‏ x y a b c d e 角度 a に対する再接近 距離 um a b c !!!!!!! d e Scanback ( μ )‏ electron a e c b d 5mm 10mm

次

Event CC Mu+ 8.7 GeV/c HPT SM1 Not workin g Ev Brick#33540

Preliminary!!!Pre liminary!!!Prelimin ary!!!Preliminary!! !Preliminary!!!Preli minary!!!Preliminar y!!!Preliminary!!!Prel iminary!!! X X X X X Y Z After 3rd step (select correct tracks)‏ Muon (p= MeV/c)‏ partner trk1 (p= MeV/c) partner trk2 partner trk3 (p= MeV/c)‏

Preliminary!!!Pre liminary!!!Prelimin ary!!!Preliminary!! !Preliminary!!!Preli minary!!!Preliminar y!!!Preliminary!!!Prel iminary!!! Momentum of electrons (measured by angular method)‏ p= MeV/c p= MeV/c p= MeV/c p=160 MeV/c PL50 PL51

次

47 Preliminary!!!Pre liminary!!!Prelimin ary!!!Preliminary!! !Preliminary!!!Preli minary!!!Preliminar y!!!Preliminary!!!Prel iminary!!! depth in lead ~ 50  m Event reconstruction in progress.. Volume-scan data being re-processed… Flight length ~5mm 20 mrad kink.

48 Preliminary!!!Pre liminary!!!Prelimin ary!!!Preliminary!! !Preliminary!!!Preli minary!!!Preliminar y!!!Preliminary!!!Prel iminary!!! depth in lead ~ 50  m Event reconstruction in progress.. Volume-scan data being re-processed… Flight length ~5mm 20 mrad kink. 崩壊 Pt ~ 0.1MeV. おそらくはハドロン 二次反応 μ 粒子

49 Preliminary!!!Pre liminary!!!Prelimin ary!!!Preliminary!! !Preliminary!!!Preli minary!!!Preliminar y!!!Preliminary!!!Prel iminary!!! Main muon ~ 40 GeV/c di-muon candidate

２００７年ランイベント解析状 況 １９反応を解析中。 １８反応で飛跡をＣＳ上に確認。 ECC 中 ８＋２（ＱＥ）反応ロケイ ションずみ。 （残りは解析中。） Kinematical な解析を始めた。 1.IP vs. momentum 2.Decay hunting & momentum 測定。 3.Pi0->gammma ->e-pair （ CHORUS,DONUT で経験ずみなので心配してな い 。）

2008 年度の展望 CNGS ビームラインの改修 ビームタイム 期待 τ ニュートリノ検出数.

52 CNGS Electronics - underground Designated “radiation safe” areas for electronics

53 Ventilation Electronics - Layout Temperature Probes Ventilation Units Target Chamber Service Gallery Proton Beam Line …electronics equipment Ventilation Chamber Junction gallery

54 Gy/yr for a nominal CNGS year of pot No shielding With shielding (caveat: the option simulated in TSG41 does not include the ventilation ducts) ‏

run : SPS schedule 147 days max for the CNGS Spread over 23 weeks (Nominal CNGS year : 200days) ‏ May 29 th November 10 th

run : expected statistics Integrated pot 55%80%70%efficiency Circulating proton Super Cycle (sec.) ‏ Number of days Nominal CNGSExpected 2008 run 1.1Tau candidate eV 2 ) ‏ 83Charm decay 16Electron events 455NC events 2070CC events 2770Total number of interactions Minimal granted by CERN If no delay in the CNGS repair ~120 evts/week

まとめ OPERA 検出器の生産は順調に進んでいる。 – 現在６１％完了。 2008 年 6 月終了。 2007 年度ニュートリノ照射 –38 事象のニュートリノ反応を得た。 – 実際のながれで複数反応検出。（解析中） 2008 年度のニュートリノ照射 –2008 年 5 月末よりニュートリノ照射 – 検出される ν τ 期待値 : １０ 反応 – 同定される ν τ 検出期待値 : １ 反応

τ detection efficiencies(in % and including BR) θ kink > 20mrad impact parameter I.P. > 5 to 20 μm 0.80 Id  + ECC connection 0.73 Kink+ kinematics 0.73  Localization OthersEvt longBR Efficiency for the:  channel 2.8% 6.8%