koto k中間子ppp.ws/ppp2015/slides/nanjo.pdf5 2008 : kobayashi and maskawa – cp-violation was...
TRANSCRIPT
![Page 1: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/1.jpg)
1
KOTO実験によるK中間子稀崩壊探索
南條 創(京都大学)
![Page 2: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/2.jpg)
2
Contents
● Motivation
● KOTO Experiment
● Prospect
![Page 3: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/3.jpg)
3
Motivation
![Page 4: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/4.jpg)
4
New Physicsはあるのか?
![Page 5: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/5.jpg)
5
● 2008 : Kobayashi and Maskawa
– CP-violation was established.
– The size is not enough to explain matter dominant universe.
– New CP-violating particle is expected in higher energy scale.
● 2013 : Englert and Higgs
– Higgs was discovered but it is far from closing the book.
– New physics in high energy scale is expected to stabilize Higgs mass.
– SUSY, little Higgs, Compositeness, Extra Dimension, …?
– Dark matter?
![Page 6: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/6.jpg)
6
● New Physicsは存在する。– 物質優勢宇宙– Dark Matter
– ...
● どうやって探す?
![Page 7: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/7.jpg)
7
New Physics Search
● High Energy Frontier ↔ High Intensity Frontier
– High energy frontier → direct production of heavy particle
– High intensity frontier → indirect access, high energy reach
一瞬の高エネルギースケール →稀なプロセス
● 標準理論の抑制● GIM, CKM,Helicity...suppression
● 精密な理論予測● Multi-process approach 多方面からフレーバ構造を明らかに
● Correlation is important.
● CP-violation is another guide.
explanation of matter dominant universe
![Page 8: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/8.jpg)
8
Why Kaon?● “Generally most powerful”
– GIM suppression of u and c quarks
– Hierarchical structure of CKM for t quark● Most suppressed in s → d transition (λ5)
– b → d (λ3) , b → s (λ2)
d s b
t
c
u
例えBs/d
→ μμがSM-likeであっても、s → dはNPでエンハンス可能
Blanke '13
![Page 9: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/9.jpg)
9
Energy Reach
MFV Generic
Tree/Strong couple 5 TeV 24000 TeV
Loop αS
0.5 TeV 2400 TeV
Loop αW
0.2 TeV 800 TeV
Tree/Strong couple ~1Loop α
S ~0.1
Loop αW
~0.03
Flavor structure
Genericの場合、K sectorが最強 → 104 TeVまでのリーチなぜまだ見えない? ↔ Energy scale, Flavor構造
Minimal Flavor Violation likeな場合、Bと強い相関 (NPでもCKMの構造を保持,新しいCPV phaseもない)
Bona '07Ishidori '13
(Bona '07)
![Page 10: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/10.jpg)
10
● NP > 1 TeV? (ATLAS,CMS)
● Non-MFV like ? (LHCb,CMS)
Buras'13
![Page 11: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/11.jpg)
11
● Rare decay
– Strong suppression from CKM
● Small theoretical uncertainty ~2%
– High energy scale
– Hadron matrix element from tree process Ke3/Kmu3
● CP-violating process
● Related to charged mode
– Grossman-Nir bound :
● Model-independent inequality w/ iso-spin rotation
Buras '15
Sensitive to new physics beyond the SM
![Page 12: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/12.jpg)
12
Direct limit 2.6x10-8 (KEK E391a)
Indirect limit 1.5x10-9 (Grossman-Nir)
SM sensitivity 2.4x10-11
10-8
10-9
10-10
10-11
New Physics?
Status
![Page 13: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/13.jpg)
13
SM extension w/ 4th generation→ ruled out Direct search
EW precision testHiggs mass
Otto '12
![Page 14: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/14.jpg)
14
from
ΔS=2とΔS=1のNPによる変化→ 同じnew phaseが支配Z'/Z with Left / Right-handed couplingLittlest Higgs with T-parity
![Page 15: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/15.jpg)
15
SM expectation (Theory)
Input from ε'/ε
MFVLeft or Right-handed coupling
Left and Right-handed coupling still can enhance Br(KL)
Direct CPV from KL → ππProgress from lattice calculation
Buras '15
![Page 16: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/16.jpg)
16
EW penguin contribute to e'/e in negative interference.Negative correlation btw Br(KL)
Buras '15
![Page 17: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/17.jpg)
17
Left- and right-handed coupling model can enhance Br(KL)
Buras '15
![Page 18: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/18.jpg)
18
Buras '15
![Page 19: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/19.jpg)
19
Littlest Higgs with T-Parity
Symmetry breaking scale
Blanke '15
![Page 20: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/20.jpg)
20
SUSY at 10-50 TeV
● 10 TeV SUSY → still large enhancement on Br(KL)
● Less correlation btw Br(KL) and ε
– 50TeV SUSY still have enhancement factor on Br(KL)
Tanimoto, Yamamoto '15
![Page 21: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/21.jpg)
21
Weekly-coupled light Z'with Lμ – Lτ coupling
● Explain g-2 with Mz'<400MeV
– also relate to B → Kμμ
from E949 experiment
KOTO already access here.
Fuyuto '14
![Page 22: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/22.jpg)
22
KOTO Experiment
![Page 23: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/23.jpg)
23
KOTO : K0 at TOkai
● J-PARC Accelerator
– High power ↔ Statistics of rare process
– Slow extraction ↔ Event pile-up due to high rate
● J-PARC 33kW (June 2015) ~ World-highest class
Extraction
400MeV
3GeV 30GeV
![Page 24: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/24.jpg)
24
Fixed Target Experiment● High intensity proton beam+ Primary target
– High intensity secondary products
● Beam line
– Transport particles of interest● Reduce unwanted particles
– Long life to transport.
30 GeV proton
Gold 15mm x 6mm x 66mm
![Page 25: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/25.jpg)
25
Bottom
Strange
Pion Neutrino source Muon source
Kaon
Tools for fixed target experiment with high intensity proton driver
Lower massLonger life time
Collider(τ、D,B,t)
Particles mass and life time
has bee a special tool for fixed target experiment
![Page 26: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/26.jpg)
26
Kaon● Low mass (0.5 GeV)
● Long life time (15m)
● Strangeness
→ Flavor Changing Neutral Current
● s → d transition
– Flavor changing neutral current (GIM)
– Strong CKM suppression
● KL → π0νν (Br 3x10-11 in SM)
– Direct CP-violation
Good for fixed target
![Page 27: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/27.jpg)
27
Beam line● 金標的 + proton
● KL beam line● 電磁石 (charged)
● 20m長尺 (short-lived)
● コリメータ (beam halo)
→ 細くシャープな中性ビーム(KL, γ, neutron)
立体角 7.8μsr ~40%lost by decay ~107 KL4x1013 proton
33kW6sec cycle
“Pencil Beam”
![Page 28: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/28.jpg)
28
Beam plug
Dipole magnet
1st collimator(4m-long)
2nd collimator(4.5+0.5m)
![Page 29: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/29.jpg)
29
Signal Reconstruction● 2γ+nothing → Calorimeter + Veto detectors
● Beam constraint → “pencil beam”
6.1m
![Page 30: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/30.jpg)
30
Detector~2m
Veto : γ/charged 10-4 – 10-6 reduction
![Page 31: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/31.jpg)
31
History
Detector upgrade
100hours
![Page 32: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/32.jpg)
32
87
97.2±0.5
10.2±0.187
Sensitivity : 1.29x10-8 (Preliminary) ~ E391a sensitivity with only 100-hour run
1st physics run in 2013
1 event in the signal box
Number of observed data → Well understood.
CKM2014
![Page 33: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/33.jpg)
33
87
97.2±0.5
10.2±0.1
87
E391a Final (5month) S.E.S : 1.11x10-8
KOTO 1st Physics run(4days) S.E.S : 1.29x10-8
Main background source in E391aHalo neutron → π0 at
Upstream detector Downstream detector
→ Largely reduced.
![Page 34: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/34.jpg)
34
87
97.2±0.5
10.2±0.1
87
Background source in KOTO
Beam pipe
CC05 CC06
1m
![Page 35: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/35.jpg)
35
Run in April-June 2015
Physics run in 2015
Physics
Calibration,Special runs
● Physics run● 5.3 times higher POT ↔ run in May 2013
● Calibration and special runs
Integrated POT for May 2013
X5.324kW
26kW 26kW
29kW
33kW
![Page 36: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/36.jpg)
36
Check with 3π0 sample• Calorimeter and KL properties
consistent with the run in May 2013.
• More detailed calibration is on-going
• Study to suppress background
Area normalizedArea normalized
Black :April-May 2015Red :May 2013
![Page 37: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/37.jpg)
37
To suppress halo neutron
● Upstream beam window
– Kapton 125um → 12.5um
– Reduce neutron scattering
● Re-alined collimator
– Reduce neutron scattering
on the collimator inner surfaceHadron interaction events
![Page 38: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/38.jpg)
38
Collimator alignment with new beam profle monitor
Lead(1.5mm)
Phosphor plate
Mirror
Re-alined collimators
![Page 39: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/39.jpg)
39
To understand hadron interaction events
Reconstructed Z vertex (mm)
Recon struc te d P
T
(MeV
/c)
Core neutronScattered at the target
10 mm thick Al
Contribution by Chonbuk Univ.
* Removed in physics run
Hadron interaction Gammas from π0
Developing BG reduction with cluster shape
Took Al-target data 70 hours > 15 times higher statics
than May 2013
![Page 40: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/40.jpg)
40
To suppress low P T events
● Beam pipe (5mm t)
SUS → Aluminum
● Installed Beam Pipe Charged Veto
– Plastic scintillator 5-mm thick
– Wavelength shifting fber readout
PMT
WLS fiber
Plastic scintillator
Beam pipe
CC05 CC06
1m
~1/60 reduction expected
![Page 41: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/41.jpg)
41
To suppress KL → 2π0
In-beam photon vetoLead and Aerogel Cherenkov detector
Lead and Acrylic Cherenkov detector
Added modules X0: 4 → 6.2
Photon punch-through inefficiency → 1/5
![Page 42: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/42.jpg)
42
Prospect
![Page 43: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/43.jpg)
43
To suppress KL → 2π0 more
• Install inner barrel detector in winter 2015
• Add 5 X0 to 13.5 X0 of current Main Barrel– Suppress punch-through ineffciency by 1/50.
Gluing fber to scintillator was mostly fnished.Module assembly will start soon.Will install it in this winter
+ Maintenance for existing broken channels in vacuum
![Page 44: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/44.jpg)
44
Plan
• NA62 will take 100 events toward 2017 for
– Push Grossman-Nir limit down.
• We will overcome our background and improve our sensitivity
2015 April-June
20172016
2015 Fall
![Page 45: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/45.jpg)
45
Long term plan
![Page 46: KOTO K中間子ppp.ws/PPP2015/slides/nanjo.pdf5 2008 : Kobayashi and Maskawa – CP-violation was established. – The size is not enough to explain matter dominant universe. – New](https://reader033.vdocuments.mx/reader033/viewer/2022041811/5e5817798e99eb2ba60d8120/html5/thumbnails/46.jpg)
46
Summary
New physics scenario
– MFV or non-MFV?● MFV like
– Br(KL→π0νν) ↔ ε'/ε > SM? will suppress Br(KL) enhancement
– Strong correlation pattern from εK
● Non-MFV with only left or right-handed coupling
– Similar to MFV
● Non-MFV with left and right-handed coupling– Z' model , generic SUSY, .. → will still enhance
Br(KL) largely
– NP in 5 TeV still enhance Br(KL) largely
– SM extension with 4 generation
→ ruled out
– Littlest Higgs with T-parity
→ under pressure from B→μμ
– KOTO already have discovery potential for light Z' with ~π0 mass
KOTO
– 1st Physics run in 2013● Sensitivity ~ current limit with only 100
hours data● New background mechanism → neutron
– Restarted in 2015 ● already took 5.3 times larger statistics● Data to study neutron background● Calibration and study to suppress neutron
background
– Prospects● Will overcome neutron background● Will search O(10-11) area for Br(KL) ~2018 ● Continue to KOTO Step2 in enlarged
Hadron Experimental Facility