Status of E14/KOTO - KEKnuclpart.kek.jp/pac/1309/pdf/KOTO_pac130925_v2a-reduced.pdfKOTO detector 3...

Status of E14/KOTO T. Nomura (KEK)

1

•Intro•Run summary•Analysis status•Preparation for next run

KOTO intro

• KOTO aims to observe KL→π0νν• CP violating process• FCNC; occurs via loop diagrams• Branching ratio is well calculated by SM

with small uncertainty (~2%)

• Good mode to search BSM contribution

• Current experimental situation• Direct limit: Br<2.6×10-8 (90%CL)

• by KEK-E391a (predecessor of KOTO)

• Grossman-Nir limit: Br<1.5×10-9 • Limit from measured Br(K+→π+νν) by BNL-787/949

2

1140.037.0 10)06.043.2( −+

− ×±=SMBRIntrinsic uncertainty

KOTO detector

3

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KAON13 @ Univ. of Michigan Ann Arbor

Principle• KL pencil beam• 2γ + nothing

• Calorimeter + Hermetic veto

3

FB NCC MB CVCsI calorimeter

CC03OEV

CC04 CC05 CC06 BHCV BHPV

LCVBCVHINEMOS

Saturday, April 20, 2013

10m

Vacuum chamber

KL

Decay region

primary p(30GeV)

target

!, n

20m beam lineSweeping magnet and collimator

KL

Hermetic veto Calorimeter

Charged

!

!

"

"

"

"

!!

!"#$%&$ '

!"##$%&'()*+,*-(&%

.(&%*/0"1$#(*&1'(0*2"##$%&'"0*&#$34%(4'*5*6+

7"8(&-#(*'9"*:'&3(*2"##$%&'"0!"#$%&'()*+*#,(-#.%/#012345#678#9:!:#

;(<<*=(-*.&(>?#@AB#3#CDE#FDG7GH#IJI

K"#!*L*%*M%&#/.#*<"?#0N>"#0"#3NN<"#2%OM"#IG#FDG77H#GECPG7

T. Shimogawa et al., NIMA 623, (2010) 585

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Principle• KL pencil beam • 2γ + nothing


• Signal reconstruction• Assume 2 gammas come from π0

• Require large transverse momentum• z vertex - Pt distribution

4

2.3 バックグラウンド 11

という関係が得られる。E1、E2 は入射 ! のエネルギーである。Eqs.(2.3-2.6)を用いると、"0 の崩壊位置 Zvtx が求まる。得られた Zvtx を使うと 2つの ! の運動量ベクトルを得ることができ、その和が "0 の運動量ベクトルになる。したがって "0 のビーム軸に垂直な運動量成分 Pt も求めることが出来る。この 2つのパラメータ Zvtx と Pt をシグナルとバックグラウンドの識別に利用する。この部分については参考文献 [21]に詳しく記述されている。またこの 2つのパラメータ平面上でシグナルイベントは Fig.2.3のように分布する。図の赤枠で囲まれる部分を signal boxと呼ぶ。

Fig. 2.2 K0L ! !0"" からの !0 の再構成。

1

10

210

Z Vertex

10001500200025003000350040004500500055006000

tP

0

50

100

150

200

250

300

350

400

pi0nunu/pi0nunu/pi0nunuann08_100.rootpi0nunu/pi0nunu/pi0nunuann08_100.root

1

10

210

Z Vertex

10001500200025003000350040004500500055006000

tP

0

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400


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Z Vertex

10001500200025003000350040004500500055006000

tP

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400


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Z Vertex

10001500200025003000350040004500500055006000

tP

0

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-110

1

10

210

Z Vertex

10001500200025003000350040004500500055006000

tP

0

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-110

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10

Z Vertex

10001500200025003000350040004500500055006000

tP

0

50

100

150

200

250

300

350

400


[MeV/c]

[mm]

Fig. 2.3 K0L ! !0"" 分布。赤枠で囲ま

れた部分を信号事象と同定する。横軸の 0は Front Barrel( 2.6.1)の上流端。

2.3 バックグラウンドKOTO実験のバックグラウンド事象 (以下 B.G.)は次の２つに分類することが出来る。1つは K0

L 自身が B.G.の源となるものである。代表的な例としては、K0L ! 2"0 の崩壊で生成

された４つの ! のうち 2 つを検出できなかった (miss veto) 場合が挙げられる。もう１つはビームコア周りに存在するハロー中性子が源となるものである。この場合，ハロー中性子は検出器中の物質と相互作用し、"0 を生成し、その信号をシグナルと見誤る事に起因する。ここではこれらのB.G.について簡単にまとめる。

2.3.1 K中間子 B.G.

Table2.1に K0L の主な崩壊モードと分岐比をまとめておく。これらは K中間子 B.G.の元にな

り得る。以下、各モードについて簡単にまとめておく。

cos � = 1�M2

⇡0

2E1E2

1

10

210

Z Vertex

10001500200025003000350040004500500055006000

tP

0

50

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Z Vertex

10001500200025003000350040004500500055006000

tP

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1

10

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Z Vertex

10001500200025003000350040004500500055006000

tP

0

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Z Vertex

10001500200025003000350040004500500055006000

tP

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-110

1

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Z Vertex

10001500200025003000350040004500500055006000

tP

0

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10

Z Vertex

10001500200025003000350040004500500055006000

tP

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[MeV/c]

[mm]

Rec

onst

ruct

ed P

t [M

eV/c

]

Reconstructed vertex [mm] 1000 3500 6000

KL ! ⇥0��̄ signal box

!0


CC03OEV


LCVBCVHINEMOS


10m

Vacuum chamber

KL

Decay region

"

"

!!

1

10

100

0.1

50

100

150

200

250

300

350

450

A narrow KL beam is the key.

• Signature of KL→π0νν = 2γ + nothing• EM calorimeter + hermetic veto

• Reconstruct kinematics• decay vertex (Z), π0 PT

4

OK T�

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3


CC03OEV


LCVBCVHINEMOS


10m

Vacuum chamber

KL

Decay region

primary p(30GeV)

target

!, n


KL


Charged

!

!

"

"

"

"

!!

!"#$%&$ '

!"##$%&'()*+,*-(&%

.(&%*/0"1$#(*&1'(0*2"##$%&'"0*&#$34%(4'*5*6+

7"8(&-#(*'9"*:'&3(*2"##$%&'"0!"#$%&'()*+*#,(-#.%/#012345#678#9:!:#

;(<<*=(-*.&(>?#@AB#3#CDE#FDG7GH#IJI



Front Barrel

Main Barrel Charged Veto

CsI calorimeterNeutron Collar

Counter

Vacuum Tank

KOTO DAQ flow

5

• Record waveforms from all channels with ADCs• Raw signal ➟ 10-pole gaussian filter ➟ 14-bit 125MHz ADC• 12-bit 500MSPS ADC for in-beam detectors

• Digitized signal information is used in the trigger system• Level 1: Energy sum, number of hits in each sub-detector• Level 2: Center of energy (COE) in the calorimeter

Trigger Rate And Data Transfer Rate

19

Flash ADC Lv2 Triggersystem

Event Building,

Lv3 trigger

DataStore

Level 1 Trigger

Data Data Data

<100kEvents/Spill <8kEvents/Spill Output Rate<2Gbps

Level 2 Trigger Level 3 Trigger

AnalogSignal

Lv1 trigger Lv2 trigger(Lv3 trigger,)Compression

30kEvents/Spill

30kEvents/Spill

~7kEvents/Spill

Input:6Gbps

Output:2Gbps

Input

OutputLimit

Data Data

192013年7月24日水曜日

KEKCC(Tsukuba)

Original run plan

6

Dec.2012 ~ 2013Engineering run in air (>8 days)

>1 week for evacuation

Engineering run in vacuum (>6 days)

>1 month for fixing potential problems

Short physics run (12 days)

>1 month for analysis and repairs

Long physics run (450 kW x days + 5days) to cross the Grossman-Nir Limit

= 30days@15kW + 5days

28

Dec

Mar

May

Jan

✔

✔

Presented at previous PAC meeting in January 2013

Actual beam time

• 2012 December : Engineering run in Air• 11kW 8.5days

• 2013 January : Engineering run in vacuum• 11kW 1.5days +15kW 6.5days

• 2013 March : Tuning for physics run• 15kW 3.5days• Terminated due to trouble in SX septum magnet

• 2013 April : Tuning for physics run• 15kW 1.5days

• 2013 May : Physics run• 15kW 1.5days + 20kW 1day + 24kW 4days• Terminated due to the accident in Hadron Hall

7

✔

✔

Completed detectors in vacuum tank

Installed downstream detectors

POT in May physics run

8

Date 18/05 19/05 20/05 21/05 22/05 23/05

16 10×

Inte

grat

ed N

of P

.O.T

.

020406080

100120140160

Integrated N of P.O.T

Date 18/05 19/05 20/05 21/05 22/05 23/05

Inte

grat

ed ti

me (

hour

s)

0

20

40

60

80

100

Integrated time

Date 19/05 26/05 02/06 09/06 16/06 23/06

16 10×

Inte

grat

ed N

of P

.O.T

.

100200300400500600700800900

1000Integrated N of P.O.T 24kW20kW

SX study

maintenance

1.6×1018 POT accumulatedfor physics run

~1/5 of original goal in May-June run

Data types

• Physics: CsI total E && no hit in veto && large COE (Lv2)• KL→π0νν

• Normalization: CsI total E && no hit in veto (PreScaled=1/30)

• KL→3π0, 2π0, 2γ• Minimum bias: CsI total E (PS=1/300)

• Calibration• KL→3π0: CsI total E && CsI hit region>4 && no hit in veto (PS=1/10)

• Cosmic ray (in off-spill)• Laser, LED• [Special run] Muon-enhanced run (with beam plug being closed)

• Accidental (random trigger)• TMON (target monitor provided by HD beam line G) (PS=1/1200)

• Clock

9

Trigger rate: Level1 28k/spill ( 27k for physics)Level2 7.4k/spill (5.2k for physics)

Misc performance during physics run

• Missing channels• 2 in calorimeter (among 2716 channels)• 2 in charged veto (among 184 channels)

• One of both-end readout; the modules were treated as single-end readout.

• 1 in CC03 (among 32 channels)• One crystal read by two PMTs; the output of the crystal got a half.

• All other channels were alive.

• Vacuum level• ~5×10-5 Pa in high vacuum region (decay region)• ~0.1 Pa in low vacuum region (detector region)

• Data transfer to KEK Computing Center• 2.7 Gbps constantly achieved (> data accumulating speed)

10

Analysis status

• January data• Intensive analysis of normalization modes

KL→3π0, KL→2π0, KL→2γ

• May data• Checked quality of data• Mostly finished calibration (energy, timing)• Started analysis of normalization modes• Veto performances under study

11

From January run

Calorimeter calibration 1 - cosmic ray

• E calibration before beam run using cosmic ray• Initial calibration• Also used for gain adjustment

of each crystal(to use in trigger)

• E calibrations of other detectors were also done with cosmic ray data.(Except for detectors that are only sensitive to particles in the beam direction.)

12

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日本物理学会 2013年秋季大会　21aSL01

Calibration• CsI の energy calibration は3種の方法を併用• Cosmic ray calibration• 宇宙線による initial energy calibration• KL→3π0 calibration• 結晶間の relative calibration

• 6γ event に対し、KL→3π0由来と仮定する事で、結晶毎に校正値の微調整を行う• Al target calibration• Absolute calibration

• ビーム中にAl (5mm thick)を挿入し、π0 を生成する。Vertex, π0 mass を拘束条件とし、校正値の絶対値を決定

8

-800 -600 -400 -200 0 200 400 600 800

-800

-600

-400

-200

0

200

400

600

800

Run14200 Event33320

10

15

20

25

30

Run14200 Event33320 energy [MeV]

n π0 π0

γ

γ

Al plate

Cosmic ray event display

downEntries 101061Mean 3.113± 4411 RMS 2.201± 948.7 Underflow 688Overflow 36Integral 9.286e+04

/ ndf 2! 55.24 / 37p0 32.2± 2499 p1 0.6± 5301 p2 0.69± 48.13 p3 16.3± 726.5 p4 7.8± 5240 p5 4.3± 241.5 vertex z position0"Reconstructed

2000 2500 3000 3500 4000 4500 5000 5500 6000

# of

eve

nts/3

0 m

m

0

500

1000

1500

2000

2500

3000


/ ndf 2! 55.24 / 37p0 32.2± 2499 p1 0.6± 5301 p2 0.69± 48.13 p3 16.3± 726.5 p4 7.8± 5240 p5 4.3± 241.5

Al target run (Run13531-13658) upEntries 95809Mean 2.88± 3927 RMS 2.036± 852.8 Underflow 1236Overflow 4Integral 8.769e+04

/ ndf 2! 95.49 / 64p0 16.7± 1438 p1 1.0± 3150 p2 0.99± 90.86 p3 1093.3± 3965 p4 680.0± 9387 p5 159.1± 2740

upEntries 95809Mean 2.88± 3927 RMS 2.036± 852.8 Underflow 1236Overflow 4Integral 8.769e+04

/ ndf 2! 95.49 / 64p0 16.7± 1438 p1 1.0± 3150 p2 0.99± 90.86 p3 1093.3± 3965 p4 680.0± 9387 p5 159.1± 2740

KL

Rec. π0 vertex [mm]

From January run

Calorimeter calibration 2 - Al target

• 5mm Al target inserted in the neutral beam• π0 production at known z position

• Absolute energy scale can be obtained.(If π0 mass is assumed, a peak can be observed at corresponding z position.)

13

Upstream Al target(removable; driven by a motor)

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Calibration• CsI の energy calibration は3種の方法を併用• Cosmic ray calibration• 宇宙線による initial energy calibration• KL→3π0 calibration• 結晶間の relative calibration

• 6γ event に対し、KL→3π0由来と仮定する事で、結晶毎に校正値の微調整を行う• Al target calibration• Absolute calibration

• ビーム中にAl (5mm thick)を挿入し、π0 を生成する。Vertex, π0 mass を拘束条件とし、校正値の絶対値を決定

8

-800 -600 -400 -200 0 200 400 600 800

-800

-600

-400

-200

0

200

400

600

800

Run14200 Event33320

10

15

20

25

30

Run14200 Event33320 energy [MeV]

n π0 π0

γ

γ

Al plate

Cosmic ray event display


/ ndf 2! 55.24 / 37p0 32.2± 2499 p1 0.6± 5301 p2 0.69± 48.13 p3 16.3± 726.5 p4 7.8± 5240 p5 4.3± 241.5 vertex z position0"Reconstructed

2000 2500 3000 3500 4000 4500 5000 5500 6000

# of

eve

nts/3

0 m

m

0

500

1000

1500

2000

2500

3000


/ ndf 2! 55.24 / 37p0 32.2± 2499 p1 0.6± 5301 p2 0.69± 48.13 p3 16.3± 726.5 p4 7.8± 5240 p5 4.3± 241.5

Al target run (Run13531-13658) upEntries 95809Mean 2.88± 3927 RMS 2.036± 852.8 Underflow 1236Overflow 4Integral 8.769e+04

/ ndf 2! 95.49 / 64p0 16.7± 1438 p1 1.0± 3150 p2 0.99± 90.86 p3 1093.3± 3965 p4 680.0± 9387 p5 159.1± 2740

upEntries 95809Mean 2.88± 3927 RMS 2.036± 852.8 Underflow 1236Overflow 4Integral 8.769e+04

/ ndf 2! 95.49 / 64p0 16.7± 1438 p1 1.0± 3150 p2 0.99± 90.86 p3 1093.3± 3965 p4 680.0± 9387 p5 159.1± 2740

KL

Rec. π0 vertex [mm]

Preliminary

From January run

Calorimeter calibration 3 - KL→3π0

• Relative calibration using 6γ from KL→3π0

• Constraint fitting with 4 parameters and 6 constraints

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3π0 calibration• KL→3π0 を用いて、結晶間の相対補正が可能• 6cluster event は KL→3π0→6γ 由来と仮定• invariant mass が π0, KL になるようγのエネルギーを補正• Ei → Ei’

• KL→3π0 event を集め、各結晶毎に補正値分布の中心値を採用

• iterationを行い、校正精度を上げる

17

E0E1

E2

E3

E4E5

(vx, vy, vz)

6 constraints(E0 + E1)

2 � ( �P0 + �P1)2 = M�0

2

(E2 + E3)2 � ( �P2 + �P3)

2 = M�02

(E4 + E5)2 � ( �P4 + �P5)

2 = M�02

5X

i=0

Ei

!2

�

5X

i=0

Pi

!2

= MKL

2

5X

i=0

xi · Ei = vx ·5X

i=0

Ei

5X

i=0

yi · Ei = vy ·5X

i=0

Ei

his_KL_mass_UseEntries 1571828

Mean 6.581± 498.2

RMS 4.653± 5.985

Underflow 0.0001882

Overflow 0.1286

Integral 0.8273

]2 invariant mass [MeV/c!6480 485 490 495 500 505 510 515 520

[a.u

.]2

# of

eve

nts

/ 0.5

MeV

/c

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045


Mean 6.581± 498.2

RMS 4.653± 5.985

Underflow 0.0001882

Overflow 0.1286

Integral 0.8273

calibration0"3

4 parameters(v

x

, vy

, vz

)

E0i

/Ei

Iteration 0Iteration1Iteration 9

Normalized by area

OK T�

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17

E0E1

E2

E3

E4E5

(vx, vy, vz)


2 � ( �P0 + �P1)2 = M�0

2

(E2 + E3)2 � ( �P2 + �P3)

2 = M�02

(E4 + E5)2 � ( �P4 + �P5)

2 = M�02

5X

i=0

Ei

!2

�

5X

i=0

Pi

!2

= MKL

2

5X

i=0

xi · Ei = vx ·5X

i=0

Ei

5X

i=0

yi · Ei = vy ·5X

i=0

Ei


Mean 6.581± 498.2

RMS 4.653± 5.985

Underflow 0.0001882

Overflow 0.1286

Integral 0.8273


[a.u

.]2

# of

eve

nts

/ 0.5

MeV

/c

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045


Mean 6.581± 498.2

RMS 4.653± 5.985

Underflow 0.0001882

Overflow 0.1286

Integral 0.8273

calibration0"3

4 parameters(v

x

, vy

, vz

)

E0i

/Ei


Normalized by area

OK T�

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17

E0E1

E2

E3

E4E5

(vx, vy, vz)


2 � ( �P0 + �P1)2 = M�0

2

(E2 + E3)2 � ( �P2 + �P3)

2 = M�02

(E4 + E5)2 � ( �P4 + �P5)

2 = M�02

5X

i=0

Ei

!2

�

5X

i=0

Pi

!2

= MKL

2

5X

i=0

xi · Ei = vx ·5X

i=0

Ei

5X

i=0

yi · Ei = vy ·5X

i=0

Ei


Mean 6.581± 498.2

RMS 4.653± 5.985

Underflow 0.0001882

Overflow 0.1286

Integral 0.8273


[a.u

.]2

# of

eve

nts

/ 0.5

MeV

/c

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045


Mean 6.581± 498.2

RMS 4.653± 5.985

Underflow 0.0001882

Overflow 0.1286

Integral 0.8273

calibration0"3

4 parameters(v

x

, vy

, vz

)

E0i

/Ei


Normalized by area

parameters:•decay vertex: vx,vy,vz

•E of i-th photon constraints:• mass of 3 pairs = Mπ0

• mass of 6γ = MKL

• vertex x,y correlate with COE

14

Calibrationusing KL→3π0

Improvements in simulation- reflection of the real world -

• Considered energy fluctuation due to photo-electron statistics

• Implemented fluctuation due to electronic noise• Though it is small (<0.5MeV equiv. per each channel)

• Overlaid accidental activities• using TMON data

• ...

15

From January run

Normalization modes

16

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p [MeV/c]0 1000 2000 3000 4000 5000 6000 7000

# of

eve

nts /

100

MeV

1

10

210

310

hKlongMom3pi0Entries 426305Mean 1.266± 2255 RMS 0.8954± 826.8 Underflow 0Overflow 0Integral 7.89e+04

Data

MC0!3"LK

momemtumLRec. K

hRatioEntries 247Mean 117.9± 3860 RMS 83.33± 1853 Underflow 0Overflow 0Integral 63.91

momentum [MeV/c]Lrec. K0 1000 2000 3000 4000 5000 6000 7000

Rat

io (D

ata/

MC

)

00.20.40.60.8

11.21.41.61.8

2 hRatioEntries 247Mean 117.9± 3860 RMS 83.33± 1853 Underflow 0Overflow 0Integral 63.91

• Mass, Momentum ともに再現できている

KL→3π0 11

ener

gy (l

og) [

MeV

]

0.5

1

1.5

2

2.5

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

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0

200

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600

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1000

CSI energy ( > 3MeV )CSI energy ( > 3MeV )

ener

gy (l

og) [

MeV

]

0.5

1

1.5

2

2.5

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

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0

200

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1000

CSI energy in clusterCSI energy in clusterRun 13710

Node 000

DstEntry 00089

nGammas 6

MyCutCondition 0

MyVetoCondition 0

KL mass 491.839923

ExtraClusterDeltaTime 0.000000

time

[ns]

150

160

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y[m

m]

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CSI time ( > 3MeV )CSI time ( > 3MeV )

time

[mm

]

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204

206

208

210

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214

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218

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000

CSI time in clustersCSI time in clusters

time

[mm

]

202

204

206

208

210

212

214

216

218

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000

CSI time in gammasCSI time in gammas

]2mass [MeV/c400 420 440 460 480 500 520 540 560 580 600

2#

of ev

ents

/ 2

MeV

/c

1

10

210

310

410

hKlongMass3pi0Entries 456640Mean 0.01634± 498.2 RMS 0.01155± 10.97 Underflow 0Overflow 1136Integral 8.338e+04

Data

MC0!3"LK

massLRec. K

hRatioEntries 2735Mean 1.068± 505.9 RMS 0.7548± 55.83 Underflow 0Overflow 1.113Integral 98.94

]2 invariant mass [MeV/c#6400 420 440 460 480 500 520 540 560 580 600

Rat

io (D

ata/

MC

)

00.20.40.60.8

11.21.41.61.8

2 hRatioEntries 2735Mean 1.068± 505.9 RMS 0.7548± 55.83 Underflow 0Overflow 1.113Integral 98.94

Accept

Δ vertex time < 3ns

Δ KL mass < 15 MeV/c2

Min. halfEt > 350 MeV

KL pt < 50 MeV/c

KL χz2 < 20

Δπ0 mass < 10 MeV/c2

Δπ0 z < 400 mm

Min. GammaE > 50 MeV

Min. Fiducial XY > 120 mm

Max. Fiducial R < 850 mm

Min. Cluster dist. > 150 mm

KL z 2000 -- 5400 mm

Preliminary Preliminary

KL→3π0 event display

Rec. mass distribution Rec. momentum distribution

OK T�

�s

d


0 1000 2000 3000 4000 5000 6000

# of

even

ts /

100

MeV

20

40

60

80

100

120 Data MC0!2"LK MC0!3"LK

MC0!-!+!"LK

momemtumLRec. K

hRatioEntries 102Mean 159± 3382 RMS 112.5± 1609 Underflow 0Overflow 0Integral 57.07

momentum [MeV/c]0 1000 2000 3000 4000 5000 6000

Rat

io (D

ata/

MC

)

00.20.40.60.8

11.21.41.61.8

2 hRatioEntries 102Mean 159± 3382 RMS 112.5± 1609 Underflow 0Overflow 0Integral 57.07

250 300 350 400 450 500 550 600

2#

of ev

ents

/ 4

MeV

/c

100

200

300

400

500

600


MC0!-!+!"LK

massLRec. K


]2 invariant mass [MeV/c#4250 300 350 400 450 500 550 600

Rat

io (D

ata/

MC

)

00.20.40.60.8

11.21.41.61.8


ener

gy (l

og) [

MeV

]

0.5

1

1.5

2

2.5

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


ener

gy (l

og) [

MeV

]

0.5

1

1.5

2

2.5

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


Node 000

DstEntry 00081

nGammas 4

MyCutCondition 0

MyVetoCondition 0

KL mass 501.087490


time

[ns]

100

150

200

250

300

350

400

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


time

[mm

]

198

200

202

204

206

208

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


time

[mm

]

198

200

202

204

206

208

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


• こちらもMass, Momentum ともに再現している

KL→2π0 12

Accept


Δ vertex time < 3nsΔ KL mass < 15 MeV/c2


KL pt < 50 MeV/c

KL χz2 < 20


Δπ0 z < 400 mm





KL z 2000 -- 5400 mm

KL beam exit XY < 50 mm

Max. shape χ2 < 5

CV Veto < 1.5 MeV

MB Veto < 5 MeV

CsI Veto < 3 MeV(distance dependent)



KL→3π0

KL→2π0

(loose veto)

Simulation well reproduced data (KL yield, spectrum, detector response).

From May run

Trigger quality check

17

a

CsI Trigger• CsIの総エネルギーに対して閾値550MeV を設定。

• Trigger Rate:120kHz

• OnlineとOfflineの違い:　Gain補正、Pedestalの変動

13

Lv1

CsIの総和の波形

Time [clock]

Puls

e He

ight

[ADC

cou

nts]

CsI: Offline Energy Distribution

Threshold550MeV

preliminary

Threshold:Height-Pedestal>5000 ADCcount

132013年9月21日土曜日

CsI total energy (offline analysis)

MB

NCC

CV

CC03

Threshold check (with minimum bias data) Blue: all Red: with on-time hit flag

Online threshold= 50MeV

thr.=1MeV

thr.=60MeV thr.=60MeV

Trigger Rate Stability• いずれも RMS/Mean=1~2%で安定。• Lv1Trigger のRequestとAcceptの違いはL2のLiveTime

• Lv1 Trigger 自体はほぼ dead time less

• Lv2 Triggerにはデッドタイムがある。

9

#of Trig./Spill(1spill~2sec)

Lv1 TriggerRequest

Lv1 TriggerAccept

Lv2 TriggerAccept

92013年9月21日土曜日

Stability of trigger (Ratio of Lv1 accept/request indicates Lv2 live time.)

Date

From May run

Veto detector response

18

M(4γ) w/o veto cut

Entries 6321Mean 357.3RMS 75.2Underflow 0Overflow 33Integral 6288

2#

of e

vent

s/10

MeV

/c

0

100

200

300

400

500

600Entries 6321Mean 357.3RMS 75.2Underflow 0Overflow 33Integral 6288

massLRec. K

Entries 4178Mean 344.3RMS 64.12Underflow 0Overflow 21.55Integral 5606

Entries 4178Mean 344.3RMS 64.12Underflow 0Overflow 21.55Integral 5606Entries 18164Mean 488.7RMS 40.89Underflow 0Overflow 0.2084Integral 540.6

Entries 18164Mean 488.7RMS 40.89Underflow 0Overflow 0.2084Integral 540.6Entries 107Mean 347.9RMS 77.94Underflow 0Overflow 0Integral 92.31

Entries 107Mean 347.9RMS 77.94Underflow 0Overflow 0Integral 92.31

Entries 18164Mean 488.7RMS 40.89Underflow 0Overflow 0.2084Integral 540.6








Data MC0/3ALK MC0/0/ALK

MC0/-/+/ALK

]2mass [MeV/c300 400 500 600 700

300 400 500 600 7002D

ata/

MC

/10

MeV

/c

0.51

1.52

Preliminary

CV total energyEntries 79747Mean 0.3576RMS 0.6119Underflow 7711Overflow 1250Integral 7.079e+04

energy [MeV]0 1 2 3

# of

eve

nts/0

.05

MeV

210

310

410

Entries 79747Mean 0.3576RMS 0.6119Underflow 7711Overflow 1250Integral 7.079e+04

CV Veto total energy


Entries 56316Mean 0.3154RMS 0.5354Underflow 5352Overflow 753Integral 6.975e+04Entries 24676Mean 0.2736RMS 0.4822Underflow 54.24Overflow 5.329Integral 675.1

Entries 24676Mean 0.2736RMS 0.4822Underflow 54.24Overflow 5.329Integral 675.1Entries 2839Mean 1.714RMS 0.9399Underflow 57.8Overflow 453.8Integral 1938

Entries 2839Mean 1.714RMS 0.9399Underflow 57.8Overflow 453.8Integral 1938



MC0/-/+/ALK

energy [MeV]0 1 2 3

0 1 2 3

Dat

a/M

C/0

.05

MeV

0.51

1.52

Preliminary

MB total energyEntries 79747Mean 16.97RMS 19.42Underflow 0Overflow 3Integral 7.974e+04

energy [MeV]0 50 100 150 200

# of

eve

nts/5

MeV

1

10

210

310

410Entries 79747Mean 16.97RMS 19.42Underflow 0Overflow 3Integral 7.974e+04

CBAR Inner Veto energy

Entries 56316Mean 17.16RMS 18.94Underflow 0Overflow 2.694Integral 7.586e+04

Entries 56316Mean 17.16RMS 18.94Underflow 0Overflow 2.694Integral 7.586e+04Entries 24676Mean 2.349RMS 8.747Underflow 0Overflow 0Integral 734.6

Entries 24676Mean 2.349RMS 8.747Underflow 0Overflow 0Integral 734.6Entries 2839Mean 8.681RMS 15.89Underflow 0Overflow 0Integral 2449




MC0/-/+/ALK

energy [MeV]0 50 100 150 200

0 50 100 150 200

Dat

a/M

C/5

MeV

0.51

1.52

Preliminary

Entries 79747Mean 340RMS 65.15Underflow 0Overflow 289Integral 7.946e+04

]2mass [MeV/c300 400 500 600 700

2#

of e

vent

s/10

MeV

/c

10

210

310

410 Entries 79747Mean 340RMS 65.15Underflow 0Overflow 289Integral 7.946e+04

massLRec. K


Entries 56316Mean 337.6RMS 62.88Underflow 0Overflow 266.7Integral 7.559e+04Entries 24676Mean 487.8RMS 43Underflow 0Overflow 0.4168Integral 734.2

Entries 24676Mean 487.8RMS 43Underflow 0Overflow 0.4168Integral 734.2Entries 2839Mean 350.2RMS 84.31Underflow 0Overflow 6.901Integral 2442


Entries 24676Mean 487.8RMS 43Underflow 0Overflow 0.4168Integral 734.2







Entries 79747Mean 340RMS 65.15Underflow 0Overflow 289Integral 7.946e+04


MC0/-/+/ALK

]2mass [MeV/c300 400 500 600 700

300 400 500 600 7002D

ata/

MC

/10

MeV

/c

0.51

1.52

Preliminary

•MB total E<5MeV•CV total E<1.5MeV•Only 4 clusters in CsI

• Analysis using minimum bias data

• Comparison between data and simulation

Preparation for next-level run

• Upgrade of barrel photon veto• Add Inner Barrel (IB) to increase radiation length

(Realization of thicker barrel photon veto, planned in the proposal)

• Completion of Beam Hole Photon Veto (BHPV)• Design: 25 modules, Current: 12 modules

• R&D of new beam hole charged veto (BHCV) for higher intensity

• Upgrade of trigger system

19

Osaka, Chicago, KEK, ...

Kyoto, Yamagata

Kyoto, Korean groups

Michigan, Chicago, Arizona State, Osaka, ...

OK T�

�s

d




3


CC03OEV


LCVBCVHINEMOS


10m

Vacuum chamber

KL

Decay region

primary p(30GeV)

target

!, n


KL


Charged

!

!

"

"

"

"

!!

!"#$%&$ '

!"##$%&'()*+,*-(&%

.(&%*/0"1$#(*&1'(0*2"##$%&'"0*&#$34%(4'*5*6+

7"8(&-#(*'9"*:'&3(*2"##$%&'"0!"#$%&'()*+*#,(-#.%/#012345#678#9:!:#

;(<<*=(-*.&(>?#@AB#3#CDE#FDG7GH#IJI



Inner Barrel (IB)

MB 14X0 + IB 5X0

3m

MB 14X0

Front Barrel5.5m

Decay region

Calorimeter

• To suppress KL→2π0 background to the level of 10-11

(necessary to go beyond G-N limit)

• 25 layers of Pb1mm+scinti.5mm sandwich, WLSF readout

20

Status of Inner Barrel

• Fabrication is underway.• Pb, scinti, WLSF have been delivered.• Grooving scintillator plate is in process.• Glueing WLSF to scintillator is being done at

KEK-Tsukuba.

• Will complete fabrication of scintillator+WLSF layers in this fiscal year.

• Mechanical structure is being designed, collaborating with an engineer of U of Chicago.

• Construction and installation schedule will be considered along with the whole plan of hadron hall works.

21

実機の製作

＊現在44枚のシンチレータが製作済み

＊8月中旬より実機のためのシンチレータとWLSFの接着作業を開始＊自動ステージによる接着剤の塗布＊紫外線照射により硬化

152013年9月20日金曜日

UV curing of adhesive

実機の製作

＊現在44枚のシンチレータが製作済み

＊8月中旬より実機のためのシンチレータとWLSFの接着作業を開始＊自動ステージによる接着剤の塗布＊紫外線照射により硬化

152013年9月20日金曜日

application of glueSupported by KAKENHI Grant-in-Aid and Japan-US program (+ KEK budget)

Other works to do (other than upgrade)

• We must move our counting house to other place,in accordance with construction of COMET building.

• Maybe twice; current house -> temporal hut -> room in COMET building

• We must rebuild the shield wall of our experimental area, when new K1.1 beam line is seated.

• To accommodate the K1.1 beam dump...

• We must move our trigger system, which is now located just outside of our experimental area.

• To release the space outside the experimental area, which will be used for new beam lines in future.

22

Schedule (and budget) will be considered with the whole work plan in hadron hall.

Summary

• KOTO completed detector construction for 1st physics run and took physics data in May 2013• Original goal: to cross the Grossman-Nir limit • Achieved: ~4 day run with 24kW beam;

accumulated ~1/5 of planned POT

• We are now analyzing the data, expecting we can improve KEK-E391a upper limit.

• Preparation for next-level physics run is also underway.• Fabrication of Inner Barrel, etc...

23

Backup

25

40ns

20mV

Sample of CsI signal

Raw signal Recorded waveform(after 10-pole gaussian filter)

26

Dead time in Lv2

Lv2 Trigger module

FlashADC

Data

2Gb memory

Buffer

Lv2TriggerControl

CoE

Write

Optical link(2.5Gbps)

1Gbps Ethernet

2Gb memory

Readout Data

Lv1trigger

Lv3PCfarm

Lv2 triggerLv1Trigger

BufferFull

136µs/event

• Lv2 BUSY when input FIFOs (depth=7) are occupied;• in case rejected: just clear FIFO = enough fast (>100kHz)• in case accepted: data transfer from FIFO to memory limits the time

to release FIFO ==> capacity ~7kHz

27

Another background is !0 production from beam neutrons interactingwith residual gas in the decay region. In order to suppress this background,the decay volume is evacuated to 10!5 Pa, as was obtained in E391a byseparating the detector and the decay region with a thin film.

Figure 14: Schematic view of detector setup.

4.3.1 Calorimeter

The electromagnetic calorimeter measures the positions and energies of pho-tons to reconstruct !0 in the K0

L ! !0"" decay. In the E391a experiment,the Calorimeter was made of 576 pure CsI crystals. Each crystal was 7.0"7.0cm2 and 30-cm long (16 X0) [59].

For the experiment at J-PARC, we plan to replace these crystals with thepure CsI crystals used in the calorimeter of the Fermilab KTeV experiment.The crystals, called “KTeV CsI crystals” hereafter, are smaller in the crosssection and longer in the beam direction (50 cm, 27 X0) than the crystals inE391a, which ensures us much better performance in the new experiment.Figure 15 shows the layout of the new Calorimeter, which then consists of2576 crystals. These crystals are of two sizes, 2.5 " 2.5 " 50 cm3 for thecentral region (2240 blocks), and 5.0"5.0"50 cm3 for the outer region (336blocks) of the Calorimeter.

The reasons for replacing the calorimeter are as follows.

• Reduce the probability of missing photons due to fused clusters.If two photons hit the Calorimeter close to each other, the generatedshowers will overlap and be misidentified as a single photon. Figure 16shows an event display for two photons that enter the CsI Calorimeterwith 6-cm separation. By using the KTeV CsI crystals, two photons

28

K0L � 3�0

Blue: events with 2γ clustersRed: after kinematic cuts for analysis

Require all photons in CsI

COE distribution (simulation)

28

# of triggers in May runtrigger type condition Prescale

factor# of events@L1(/spill)

# of events@L2(/spill)

physics Et&Veto&COE 1 27K 5.2K

normalization Et&Veto 30 0.9K 0.7K

Minimum bias Et 300 0.9K 0.7K

3pi0 calibration Et&RC&Veto 10 0.4K 0.3Kcosmic ray(3types) 1 0.2K 0.2Kexternal(2types)

1(1200 for TMON) 0.2K 0.2K

L1 Request: 28.0K events/spill, L1 Accept : 23.0K events/spillL2 Accept : 7.4K events/spill

313年7月25日木曜日

29

Cut conditions for KL→3π0, 2π0

OK T�

�s

d


p [MeV/c]0 1000 2000 3000 4000 5000 6000 7000

# of

eve

nts /

100

MeV

1

10

210

310

hKlongMom3pi0Entries 426305Mean 1.266± 2255 RMS 0.8954± 826.8 Underflow 0Overflow 0Integral 7.89e+04

Data

MC0!3"LK

momemtumLRec. K


momentum [MeV/c]Lrec. K0 1000 2000 3000 4000 5000 6000 7000

Rat

io (D

ata/

MC

)

00.20.40.60.8

11.21.41.61.8


• Mass, Momentum ともに再現できている

KL→3π0 11

ener

gy (l

og) [

MeV

]

0.5

1

1.5

2

2.5

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


ener

gy (l

og) [

MeV

]

0.5

1

1.5

2

2.5

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


Node 000

DstEntry 00089

nGammas 6

MyCutCondition 0

MyVetoCondition 0

KL mass 491.839923


time

[ns]

150

160

170

180

190

200

210

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


time

[mm

]

202

204

206

208

210

212

214

216

218

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


time

[mm

]

202

204

206

208

210

212

214

216

218

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


]2mass [MeV/c400 420 440 460 480 500 520 540 560 580 600

2#

of e

vent

s / 2

MeV

/c

1

10

210

310

410

hKlongMass3pi0Entries 456640Mean 0.01634± 498.2 RMS 0.01155± 10.97 Underflow 0Overflow 1136Integral 8.338e+04

Data

MC0!3"LK

massLRec. K


]2 invariant mass [MeV/c#6400 420 440 460 480 500 520 540 560 580 600

Rat

io (D

ata/

MC

)

00.20.40.60.8

11.21.41.61.8


Accept


Δ KL mass < 15 MeV/c2


KL pt < 50 MeV/c

KL χz2 < 20


Δπ0 z < 400 mm





KL z 2000 -- 5400 mm



OK T�

�s

d


0 1000 2000 3000 4000 5000 6000

# of

eve

nts /

100

MeV

20

40

60

80

100


MC0!-!+!"LK

momemtumLRec. K

hRatioEntries 102Mean 159± 3382 RMS 112.5± 1609 Underflow 0Overflow 0Integral 57.07

momentum [MeV/c]0 1000 2000 3000 4000 5000 6000

Rat

io (D

ata/

MC

)

00.20.40.60.8

11.21.41.61.8

2 hRatioEntries 102Mean 159± 3382 RMS 112.5± 1609 Underflow 0Overflow 0Integral 57.07

250 300 350 400 450 500 550 600

2#

of e

vent

s / 4

MeV

/c

100

200

300

400

500

600


MC0!-!+!"LK

massLRec. K


]2 invariant mass [MeV/c#4250 300 350 400 450 500 550 600

Rat

io (D

ata/

MC

)

00.20.40.60.8

11.21.41.61.8


ener

gy (l

og) [

MeV

]

0.5

1

1.5

2

2.5

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


ener

gy (l

og) [

MeV

]

0.5

1

1.5

2

2.5

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


Node 000

DstEntry 00081

nGammas 4

MyCutCondition 0

MyVetoCondition 0

KL mass 501.087490


time

[ns]

100

150

200

250

300

350

400

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


time

[mm

]

198

200

202

204

206

208

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


time

[mm

]

198

200

202

204

206

208

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


• こちらもMass, Momentum ともに再現している

KL→2π0 12

Accept

Δ vertex time < 3nsΔ KL mass < 15 MeV/c2


KL pt < 50 MeV/c

KL χz2 < 20


Δπ0 z < 400 mm





KL z 2000 -- 5400 mm

KL beam exit XY < 50 mm

Max. shape χ2 < 5

CV Veto < 1.5 MeV

MB Veto < 5 MeV




KL→3π0 KL→2π0

30

OK T�

�s

d


0 1000 2000 3000 4000 5000 6000

# of

even

ts /

100

MeV

20406080

100120140160

Data MC!2"LK MC0#3"LK MC0#2"LK

MC0#-#+#"LK MC$e#"LK MC!$e#"LK

momemtumLRec. K


momentum [MeV/c]0 1000 2000 3000 4000 5000 6000

Rat

io (D

ata/

MC

)

00.20.40.60.8

11.21.41.61.8


0 20 40 60 80 100 120 140 160 180 200

# of

eve

nts /

2.5

MeV

/c

20406080

100120140160180200 Data

MC!2"LK MC0#3"LK MC0#2"LK


transverse momentumLRec. K


transverse momentum [MeV/c]0 20 40 60 80 100 120 140 160 180 200

Rat

io (D

ata/

MC

)

00.20.40.60.8

11.21.41.61.8


ener

gy (l

og) [

MeV

]

0.6

0.8

1

1.2

1.4

1.6

1.8

2

2.2

2.4

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


ener

gy (l

og) [

MeV

]

0.6

0.8

1

1.2

1.4

1.6

1.8

2

2.2

2.4

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


Node 010

DstEntry 04094

nGammas 2

MyCutCondition 0

MyVetoCondition 0

KL mass 0.000000


time

[ns]

185

190

195

200

205

210

215

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


time

[mm

]

208

210

212

214

216

218

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


time

[mm

]

208

210

212

214

216

218

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


• Transverse momentum, Momentum ともに再現できている• KL→2γはKL massを仮定するため、mass分布は無し

KL→2γ 13

Accept




KL pt < 50 MeV/c


Max. GammaE > 600 MeV


Max. Fiducial R 450 -- 850 mm


KL z 2000 -- 5000 mm

Max. shape χ2 < 5

CV Veto < 1 MeV

MB Veto < 5 MeV


KL→2γ event display

Rec. transverse momentum distribution Rec. momentum distribution

KL→2γ

OK T�

�s

d


0 1000 2000 3000 4000 5000 6000

# of

even

ts /

100

MeV

20406080

100120140160

Data MC!2"LK MC0#3"LK MC0#2"LK


momemtumLRec. K


momentum [MeV/c]0 1000 2000 3000 4000 5000 6000

Rat

io (D

ata/

MC

)

00.20.40.60.8

11.21.41.61.8


0 20 40 60 80 100 120 140 160 180 200

# of

eve

nts /

2.5

MeV

/c

20406080

100120140160180200 Data

MC!2"LK MC0#3"LK MC0#2"LK


transverse momentumLRec. K


transverse momentum [MeV/c]0 20 40 60 80 100 120 140 160 180 200

Rat

io (D

ata/

MC

)

00.20.40.60.8

11.21.41.61.8


ener

gy (l

og) [

MeV

]

0.6

0.8

1

1.2

1.4

1.6

1.8

2

2.2

2.4

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


ener

gy (l

og) [

MeV

]

0.6

0.8

1

1.2

1.4

1.6

1.8

2

2.2

2.4

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


Node 010

DstEntry 04094

nGammas 2

MyCutCondition 0

MyVetoCondition 0

KL mass 0.000000


time

[ns]

185

190

195

200

205

210

215

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


time

[mm

]

208

210

212

214

216

218

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


time

[mm

]

208

210

212

214

216

218

x [mm]-1000 -800 -600 -400 -200 0 200 400 600 800 1000

y[m

m]

-1000

-800

-600

-400

-200

0

200

400

600

800

1000


• Transverse momentum, Momentum ともに再現できている• KL→2γはKL massを仮定するため、mass分布は無し

KL→2γ 13

Accept



KL pt < 50 MeV/c


Max. GammaE > 600 MeV


Max. Fiducial R 450 -- 850 mm


KL z 2000 -- 5000 mm

Max. shape χ2 < 5

CV Veto < 1 MeV

MB Veto < 5 MeV


KL→2γ event display

Rec. transverse momentum distribution Rec. momentum distribution

Other works to do- against activities from primary beam line -

31

Put$200$water+tanks$at$the$north+upstream$wall$in$our$area�

Es6mated$direc6on$of$par6cles$$(from$MB$rate$analysis)�

Temporal countermeasure in March = Shielding by a stack of water tanks

Other works to do- against activities from primary beam line -

32

2.E+04'

2.E+05'

1'2' 3'

4'5'

6'

7'

8'

9'

10'

11'

12'

13'14'

15'16'17'

18'19'20'

21'

22'

23'

24'

25'

26'

27'

28'

29'30'

31' 32'Main%barrel%outer-module%rate�

1�Run'3�8��beam6tuning��beam6tuning��

north'

south'

top'

bo?om'

top'

north' south'

bo?om'Primary'beam'line� Embedded'iron�

Water6tanks�

Jan runMarch (before tuning)March (after tuning)

Plan to use heavier shielding material (iron) to reduce activities more.

Status of E14/KOTO - KEKnuclpart.kek.jp/pac/1309/pdf/KOTO_pac130925_v2a-reduced.pdfKOTO detector 3...

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Transcript of Status of E14/KOTO - KEKnuclpart.kek.jp/pac/1309/pdf/KOTO_pac130925_v2a-reduced.pdfKOTO detector 3...