5A：超対称性探索　with mET

(1)

5A：超対称性探索　with mET

1 SUSYの御利益と代表的なBreaking 機構　 2 mSUGRAの簡単なmass spectrum

3   ＬＨＣでの生成過程 4   崩壊過程

5   期待されるイベントトポロジー 6   BGのまとめ

7   No lepton, One lepton, Stop 8   見えない理由

9   EW gaugino や　縮退など 9 まとめ

126GeVだと思うと�

（2）�SUSYだとすると、いろいろ�

（1） Naturalness?��

何か別の機構�

O(10)＊ 125GeV 〜

�O(1) TeVにあることの重要な示唆

Minimal model A 〜�√6 mstop

stop mixingが大きくないと�かなりつらくなる Aが小さいMinimal model

gluino 10TeV 近い重いSUSUY �

�

でもGUT近くでも問題はなんとか回避はできる。。�

Bs→μμで制限�

1. おまけがある

2. Aがfull mixingになっている

3. 重いSUSY��

(2)

　　　　通常の粒子　　　　　超対称性粒子 S=1/2

charged lepton: e, μ,τ neutrino: ν, ν, ν quark: u, c, t 　　　 d, s, b

S=0

charged scalar lepton: e, μ,τ scalar neutrino: ν, ν, ν scalar quark: u, c, t d, s, b S=1

photon : γ (B⁰ and W⁰) Weak Boson : W^+-, Z gluon: g

S=1/2

Bino : B⁰ Wino : W^+-, W⁰ gluino: g S=0 Higgs: h, H,A, H ^+-

S=1/2

Higgsino: H⁰1, H⁰2, H^+- S=2 Graviton: G S=3/2 gravitino: G

~ ~ ~

~ ~

~

~ ~ ~

~

~ ~

フェルミオンとボソンを交換する変換（超対称性変換） (1) 力の大統一 (2) 暗黒物質 (3) 階層問題の解決 (4) LocalなSUSY -> 重力が出てくる　　{QQ}=P (平行）

など実益として多くの利点標準理論を超える新しい素粒子理論の中で最も期待されているもの

1 超対称性の御利益

自由度�

3つの力（電磁気力、弱い力、強い力）の強さをLEP等で精密に測定。

繰り込み群方程式を解いて高いエネルギーでの力の強さを計算

超対称性粒子が 1TeV付近にあると、3つの力は

10¹⁶GeVで一つの力になる可能性が示された。

è　力の大統一

力の大統一(Grand Unification)

左図を物理の歴史と重ねてみると、

この大統一のもつ大きな意味が理解出来る。

重力を取り込んだ理論を作る上でも超対称性は不可欠

�

(3)

SUSYは破れている。（でないと511keVのスカラー電子）�

SUSYを破る場（Ftermなど)があって、その効果が伝わっている。�

SUGRA� GMSB� AMSB�

伝えている機構� Planck scaleの物理あるsingletを手でいれる。

M=M_pl, √F=10^11�

破る場とSM場の両方の電荷をもつセクター

（メッセンジャー）

M=10-1000TeV, √F=10^5-9�

重力場自体 M=M_pl, √F=10^13�

LSP� neutralino ~ O(100GeV)

density ○-△�（残りすぎ）� Gravitino ~O(eV-KeV)

Hot ? X-△� Wino ~ O(100GeV)

density ○

FCNC� FCNC� m0 縮退を仮定� FCNCはOK � m0を手で入れないとタキオ

ン、m0>>TeVならFCNC�

Gravitino� 100-1000GeV

reheating X� <1GeV

たくさん出来るがDM �○ � 10-1000TeV��（〜m0?) reheating 程度�○�

m0,m1/2,

sign(mu), tanβ、A� Λ、M, n

tanβ, sign(mu), Cgra NLSPが鍵 �

m3/2 (m0) tanβ, sign(mu)�

€

m

_susy

=< F > / M

_mediation

� 4.5個のパラメター(mSugra) ：

�

m

_o

, m

_1/2

, tanβ, A

₀

, sign(μ)

(mass @GUT) (VEV) (scalar 3点) (Higgsino mass)

S=0

charged scalar lepton: e, μ,τ scalar neutrino: ν, ν, ν scalar quark: u, d, c, s, t, b S=1/2

Bino : B0 (M1 ) Wino : W^+-, W0 (M2) gluino: g (M₃)

S=1/2

Higgsino: H⁰₁, H⁰₂, H^+-(μ) S=3/2 gravitino: G

~ ~ ~

~ ~

~

~ ~

~

~ ~

~

GUT scale(2*10¹⁶GeV)で、共通の質量、3点結合ヒッグスセクターもsfermion, gauginoと同じ�

M₁：M₂ ：M₃ = α₁： α₂： α₃�＝�

0.4 m_1/2 : 0.8 m_1/2 : 2.6 m_1/2

1TeVくらい�

GUTのスケール�

自然にマイナスになる。

これが自発的対称性の破れヒッグス機構�

2 ��mSUGRAのmass spectrum�

GUTでのunification M�

(4)

• Coloured partciles ��は重い

��

•  第3世代の�� は軽い。

(Yukawa+LR mixingの効果)

�DMとの関係では�τが大切

��

+ 0.50D

D = M

_Z²

cos 2β < 0 ( Higgs )

( )

€

f ˜

€

( ˜ g , ˜ q )

Mass＠EW

Running effect 結合が強い程太る�

共通＠GUT

€

m

²

(˜ τ ) = m

₀²

+ 0.52m

_1/2²

+ m

_τ²

− 0.27D −m

_τ

(A

_τ

+ µtanβ)

−m

_τ

(A

_τ

+ µtanβ) m

₀²

+ 0.15m

_1/2²

+ m

_τ²

−0.23D

%

&

' (

) *

tanβが大きいと,τが大切�

LとR：SU(2)に対する電荷を持っているか否かでfermionも2つに分類される。

それ以外の量子数は同じ。

��SU(3)：強い力�一番太る

��SU(2) : 少し太る��L > R

1TeV scaleだともうすこし係数小さくなります�

Chargino/ Neutralino

S=1/2 Bino : B⁰ Wino : W^+-, W⁰

S=1/2

Higgsino: H⁰₁, H⁰₂, H^+-

〜

〜〜

〜 μ

m₂ m₁

€

B ˜

⁰

W ˜

⁰

H ˜

₁⁰

H ˜

₂⁰

"

#

$

%

&

cosβ −M

_Z

cosθ

_W

sinβ

sinβ −µ 0

%

&

' ' ' '

(

)

2.  M₁, M₂,μ,Mzの大小関係が大切。Mzが小さいとすれば、

LSPは、Bino-like(M₁が小）、 Wino-like(M₂が小), higgsino-like(μが小）。。

��DMの性質（結合定数、質量）はこれらの大小関係が鍵とな

€

る。��

χ ˜

₁⁰

CharginoもM₂,μの混合状態でWino-like とhiggsino-like

同じ量子数を持っている状態は混合し、

質量のeigenstate を作る。

これが、

Chargino (charged wino + charged higgsino) Neutralino(bino, neutral wino+ neutral higgsino)

(5)

€

( ˜ g g ˜ , ˜ g q ˜ , ˜ q q ˜ )

• 大きな生成断面積

•  ただの強い相互作用:

�mass以外は SUSY parameter に強く依存しない。

m( ˜ g ) < m( ˜ q )

€

m( ˜ g ) ≈ m( ˜ q )

€

m( ˜ g ) > m( ˜ q )

€

g ˜ →

qq B ˜

⁰

(≈ 1) qq W ˜

⁰

(≈ 2) qq W ˜

^±

(≈ 4)

€

g → ˜ t t ˜

₁

b b ˜

₁

€

g ˜ → q q ˜

€

q ˜

_L

→ q W ˜

⁰

(≈ 1) q W ˜

^±

(≈ 2)

g ˜ , ˜ q のdecay table

Strong interaction EW interaction

Massの関係やB,Wとχの関係、第3世代などが、モデル依存�

4 崩壊過程�

I

II

Decay to Higgs

€

m( ˜ χ 2 0)−m( ˜ χ 1

0)>m(h)

€

χ ˜ 2 0→hχ ˜ 1

0

χ ˜ 1

±→W^±χ ˜ 1 0

III IV

€

χ ˜ ₁ ^± , ˜ χ ₂ ⁰ ^{の崩壊モードについて} �

2-Body decay chain

€

m( ˜ χ 1

±),m( ˜ χ 2

0)>m(˜  ^±)

€

χ ˜ 1

±→˜  ^±ν→^±χ ˜ 1 0ν χ ˜ 2

0→˜  ^±^→^±^χ ˜ 1 0

Decay to W/Z

€

m(h)>Δm>m(W,Z)

€

χ ˜ 2 0→Z⁰χ ˜ 1

0

χ ˜ 1

±→W^±χ ˜ 1 0

3-Body decay

€

Δm<m(W,Z)

€

χ ˜ 2 0→ff ˜ χ 1

0

χ ˜ 1

±→ff ˜ χ 1 0

これらは基本的にkinematics だけであり、依存性は少ないが Higgsino成分？？

Sfermion propagatorで3body LEPで見ていた所は、IVの下の方のあたり。�

(7)

多段のカスケード崩壊が観測される。

（非常に特徴的）��

初めに colored particleが出来て、

Chargino/Neutralinoは、

カスケード崩壊の途中で出てくる。

最後は、neutralino_1が出てくる。 -> mETを作る。

AMSB，GMSBも基本的に同じ LSPが何か？ぐらいのちがい

（NLSPの寿命が長くない限り）

event topologies of SUSY

€

/ E

_T

multi leptons + High P

_T

jets + b-jets τ-jets

High Pt jetはcolored sector & おまけはEW sectorの情報を運んでいる�

5 期待されるイベントトポロジー

(8)

15

mE

_T

Without

mE

_T

Njet>=3

SUSY

Nothing (or soft jet) One lepton

Dilepton, 3L

Njet~ 0

direct

tau, di-tau

��

Njet〜2

€

g ˜ g ˜ , ˜ g q ˜

€

χ ˜

LSP/NLSP

Colored sector EW sector

Photon(s)

€

/ R

Multi-leptons+(jets)+ (mE_T)

Exotic particle Heavy Stable charged track

(stau,R-hadron) TOF in MS, Hcal

Kink/Disappearing track(chargino, stau)

R-hadron Stop in Hcal or mE_T

NLSP metastable or LSP/LL

€

˜ g

LSP�unsable

t,  b 

Exotic signal�

Standard mE

_T

signal�

General MSSM�

General MSSM � General , Small m0�

GMSB, large tanβ�

GMSB�

B-jet(s)�

€

q ˜ q ˜

Displaced Vertex

Lifetime�

100μ�

10 cm�

>10 m�

carried by LSP�

more detail classification are summarized in this figure:

direct production�

stau�

General�

mET， Multi-high Pt jetが基本

mET �は、 ν や jet energy resolution(fake mET).

Main BG processes

��(1) W + Jets W->leptonic (2) Z+jets, Z-> νν��tautau (3) top pair production (4) QCD multijet processes.

(5) WW,WZ,ZZ -> EW gaugino direct production Control regions: あるBGをenhance して�

check the various distributions. Normalizationなどをきめて

distributions in CR are extrapolated (with MC) to signal region

6. BG estimations �

(9)

BG1: Control regions (QCD)

ΔΦ(jet vs mET) <0.4 is required to enhance QCD processes.

QCD multi-jets processes becomes BG when ν emits in a heavy flavor jet or when jet energy is miss-measured ( Fake mET) .

Data is harder than PYTHIA prediction.

PYTHIA is parton shower scheme, To produce high PT jet, Q^2 of shower evolution is set high, still not enough, On the other hand, Q^2 is high

then too many jets are produced in PYTHIA and there is discrepancy.

The other MC also can not reproduce multijet + mET topology.

Meff= mET+ Σ PT (jet) � energy mis-measurement� ν�

QCD BG is estimated with real data using this CR

PYTHIA�

W + jets (1lep without b)

BG2: Control regions (W)

M

_T

< Mw & no bjets are required to select W+jets sample.

Blue shows the simulated W+jets BG.�

Slop is slightly different: Data is harder SHERPA is better to reproduce a shape.

(Not physics, just different scale for αs)

Currently

shape predicted by SHERPA /Madgraph(CMS) is used

Normalization is determined by data MC is produced with ALPGEN.

ALPGEN�

ほんとうに信用できるか？��結局 additional jetの出し方、PTの問題

PDF, αs(scale what scale is used)�

(10)

BG3: Control regions (Z)

ｑ

ｇｑ

γ、Z(-‐>ll)

Events with high PT jet are expected.

BG (Z->νν)+Jets can be estimated with�

Currently MC produced by ALPGEN/ SHERPA / MADGRAPH(CMS) are used and Normalization has been performed using data(Control region). �

we can examine using γ+Jets，Z（→μμ）+jets; But stat. is too limited for High Pt�

Large uncertainty in the signal region > 50%�

Physics process is the same as W+jets�

ほんとうに信用できるか？��Wと同じ：結局 additional jetの出し方、PTの問題 PDF, αs(scale what scale is used)�

W/ZのBGをどう評価するか考えて行かないといけない

BG4: Control regions (R)

M

_T

< M

_W

& bjets are selected to enhance tt sample

tt is not dominant BG except for mET+bjet analysis,

since σ at 7TeV is 170pb.

It becomes serious at ECM=14TeV (830pb)

Now basically We use MC even with normalization.

MC@NLO�

Problem tt+Njets,

“Additional Njets” is key still need more data and study�

けっきょく�QCDのテールの部分を理解�

(11)

7. 8TeVの代表的な結果�

•  No Lepton with mET

•  No Lepton with Njets

•  One Lepton

•  Scalar top �

mET のあるやつ　 Selec)on の概論

m0 m1/2

gluino pair (A) 4jet-like

(C) sbottom, stop Br bの解析 BG落とす High PT jets多数 or b�

squark pair (A) 2jet-like

(B) 特にm0小さいと lepton Br BG落とす為に Large mET �

gluino/squark (A) 3〜4 jet-like

(B)g->bb,ttなど�b, leptonic �

Main BG W(lnu)+jets, Z(nunu)+jets, top, QCD(2jets以外は効かない) 　　　　　　　mETを厳しくしても W/Zは結構最後まで残る。

　　　　　　　ECM 7TeV なので top σ=830pb -‐> 160pb　（断面積 1/5) W/Z が結構効く Gluino-‐>qqχ (3body)

squark-‐>qχ (2body)

Long Cascade Njet 〜 5-8�

ATLAS的発想�

(12)

No Lepton mode

Meﬀ >1900GeV (mET/Meﬀ>0.25) Data 7 events are observed BG 8.7 +-‐ 3.4 (Z 5.1 W 2.7 t 0.8)

At least 3 （high PT > 160,130,60GeV) Jets & Large mET(>475GeV) & mET is not direct to jet �

8TeV L=5.8fb

^-1�

mET と

Scalar sum of Jet activity(H

_T

)

H

_T

is used in CMS

Meff= mET+ Σ P

_T

(jet) is used in ATLAS.

agree well with BG

1 candidate in high Meff region �

300 400 500 600 700 800 H900_T (GeV)

Events / bin

10-1

1 10 102

103

= 8 TeV s -1, CMS Preliminary, 3.9 fb

b= 0) b Data (hadronic sample, n

Expected Unc.

Standard Model ±

= 100 GeV) = 800 GeV, mLSP gluino (m

0 ) χ∼ t 0 t χ∼ t t

→ g~ g~ SM + SUSY (

8TeV L=3.9 fb

^-1�

Meﬀ(4j) = 2992 GeV

MET = 1170 GeV phi=0.4

2 high PT (>150GeV) Jets pT=1335 GeV eta=0.96 phi=3.05 pT=530 GeV eta=-‐1.26 phi=-‐1.17 pT=112 GeV eta=-‐0.38 phi=2.34 pT=21GeV eta=0.13 phi=0.07

Candidate event (Hardest)

3,4 th is soft ? maybe W+jets

in the next page�

(13)

25�

1st Jet Pt (GeV/c) 0 100 200 300 400 500 600 700 800 900 1000 10-2

10-1 1 10

102 BG

Sugra(120,340) Sugra(1080,310) Higgsino(1000,200) Higgsino(100,200)

< 1

^st

Jet Pt >�

2nd Jet Pt (GeV/c) 0 100 200 300 400 500 600 700 800 900 1000 10-2

10-1 1 10

102 _BG

< 2

^nd

Jet Pt >�

3rd Jet Pt (GeV/c)

0 100 200 300 400 500

10-2 10-1 1 10

102 BG

< 3

^rd

Jet Pt >�

Jet PT of W+jets process comparing with signal�

g�

q�

q� -� W*/Z�

Proton�

high PT�

ISR g(relatively hard)�

g(relatively soft)�

2

^nd

is still hard�

3

^rd

becomes softer

1

^st

Jet�

Virtuality is high�

2

^nd

jet �

No Lepton mode 　別のアプローチ

Large m0 の時 gluino -> qq wino -> qqqq bino multijetになる一方、mETは��binoの運動量が小さくなるので小さくなる。 mETでなく jet数で感度を上げよう�

W/Z BGはおさえることができる。�

excessは�なし�

(14)

High MET analysis is useful for high M1/2 region

High PT & High jet multiplicity Analysis is useful for

Large m0 region.

(gluino production is dominant)�

gluino,squark ~ 1.5TeV gluino 950GeV

�� for Heavy squark�

heavy squark means that only gg->gluino�gluino possible at LHC. Since PDF of gluon has steep distribution, heavy gluino σ is seriously

suppressed.

If squark production is possible, valence quark can contribute, and production σ�is high for heavy (large x):

Limit within CMSSM model�

No excess in No lepton mode�

scalar mass at GUT�

gaugino mass at GUT�

One lepton Mode

electron muon

Electron (PT>25GeV) or muon (PT>20GeV) is required for trigger/ BG suppression At least 4jets(PT>80 GeV ) MET>250GeV MT>100GeV Meﬀ>800GeV

tt is dominant background processes;

��No excess was found in data @ 8TeV (L=5.8fb

^-1

)�

(15)

Topology & BG are different! No Lepton mode W,Z - >

Complementary

analysis�

One Lepton mode tt

analyses�

Limit in CMSSM framework for one lepton mode�

One Lepton mode No lepton mode

Sensitivity is worse than No lepton mode in CMSSM framework.�

◎Similar large m0: Spectrum is relatively compressed -> Lepton gains sensitivity ◎relatively Small 0 Large m1/2 enhance mET -> No lepton has good sensitivity

◎Small m0 Lepton branching increase, lepton mode has good sensitivity �

Let’s superimpose

no lepton results�

(16)

mET + jets with B jet (Stop search) 　

(A)  No Lepton + multijets(> + mET + b-jet (at least 1 or 2 )

��stop pair production ->

��stop -> b chargino (->jets + neutralino)

�� （B）One Lepton + multijets(>=4)+mET+bjet(at least 1)

��stop pair production stop -> t + neutralino

(C) Two Lepton + multijets(>=2)+mET+bjets(at least1)�

��stop pair production ->

��stop -> b chargino (->jets + neutralino)

(D) No lepton + 2 b jets + mET stop direct production

stop-> b + chargino (chargino -> LSP+soft Higgsino/Wino case)��

Stop は naturalness を考えると軽いはず�

stop pair σ�

0.5pb�

0.2pb�

0.05pb�

2012target�

(17)

Results of Topology B and C

Main BG topになるので 1 lepton MT 2 lepton の場合は MT2 �

Stop->b+chargino

(Higgsino/Wino lighter ) In both case ΔM(charhino-neutralino) becomes smaller�

PT>60,60GeV (no 3

^rd

jet > 50) MET>200GeV

good 2b jet MCT > 100GeV �

Trigger is crucial

Results of Topology D (2bjets)

ΔM > 300GeVがLHCの壁�

(18)

(1)  t+nu のkinematic 550GeV (2)  b+char nu1 < ½ char 400GeV (3)  Wino, Higgsino likeの時�あんまり�

These results does not depend strongly on SUSY models�

Distribution does not strongly depend on the the other SUSY parameters.

Main difference comes from the mass difference between LSP and the produced colored mass. ΔM

LSP mass (GeV) for Gluino mass 1TeV

mass difference between LSP and colored mass is crucial: ΔM < 300GeV → No sensitivity�

No SUSY found @ LHC (1) heavy colored (2) degenerate (3) No mET (4) NoSUSY (@ TeV scale)

Production process is just strong interaction.

It

depend

on gluino,squark mass.

LHC 14TeV�

(19)

Heavy Colored particles are heavy at LHC (especially for LHC 8TeV)

�

but EW gaugino / Higgsino/ are still light colored is shifted�

Impossible LHC @ 7 or 8 TeV�

Gaugino Direct Production

��is only possible signal. �

（1）�Heavy colored particle case

A:Colored particle has steep coefficient of RGE (AMSB model -> I will show later) B: colored mass is heavy at GUT scale�

because�

chargino1 + neutralino2 -‐> 3lepton or SS 2lepton + mET

If slepton is lighter than ch1/nu2, branching fraction including lepton increases significantly.

Otherwise, WZ+mET topology is dominant.

In this case BG WZ is large �

Heavy colored particle: 3/2 lepton modes

(20)

at least 3leptons (>20,10,8GeV) HT(sum of Jet PT) < 200GeV to reduce top BG�

No excess was found:�

Mz->ll�

Signal is expect for all regions

When Δm(ch1/nu2 vs nu1) is large,

Region IV,V has sensitive:

Heavy colored particle: 3/2 lepton modes

chargino1 + neutralino2 -‐> 3lepton or SS 2lepton + mET

WZ BG dominant in III �

Bino/Wino=1:2 �

If slepton contribution is small No limit is obtained.

Br(3L) = 50% case

M(char1,nu2) > 400GeV for M(nu1)=1/2 M

Higgsino case

(Branching lepton decreases ΔM�decrease)

No limit is set �

Since LHC is p+p, �q_bar is sea quark.

q + q_bar -> Wino Zino is suppressed

Heavy colored particle: 3/2 lepton modes

Need new idea

for Ch1Nu2 study

(21)

41�

(2)Degenerate case (UED,Mirage SUSY)�

The mirage SUSY models or the UED model:

New physics scale is close to TeV.

Degenerate spectrum is expected. �

When mass spectrum become degenerate,

the SM particles emitting from cascade decay becomes soft and sensitivity(trigger) is seriously loosen.�

If ΔM/M < 30% (Degenerated mass spectrum) current susy analysis dose not have

sensitivity�

Mcolored=1TeV @ 14TeV �

ISR jet is useful for degenerate cases �

42�

When heavy particles (high Q

²

) produce, high virtuality is necessary for incoming partons.

It is not new physics. Just QCD.

To make high virtuality state, the high PT ISR jet is emitted.

ISR jet has hard spectrum for heavy particle production,

PT depends on the mass of produced particles and independent on the decay products. �

@10TeV�

Pt distribution of the Leading Jet (UED signal) �

ch1/nu2� soft lepton� To reduce BG, soft lepton is required �

These are soft

(22)

Basic selection for the ISR +soft lepton�

No excess found � Degenerated region is covered gluino< 550GeV

Still No sensitivity > 550GeV

Need New Idea/data for > 550GeV �

ATLAS 7TeV Data�

stop (wino-bino) 400GeV�

No excess was found for all SUSY searches�

(23)

なぜTeVか

（1）Naturalness (TeV)^2 – (TeV)^2 = Mh^2

（2）EWの測定� m1/2 ~ 400-1000 GeV

（3）DM m1/2 ~400GeV��

��モデルによる��Binoはきつい�stau 縮退以外

（4）muon g-2 ��軽い

（5）GUT��10TeVでもいい��

そろそろ�何かをあきらめていかねばならない。

46

mE

_T

Without

mE

_T

Njet>=3

SUSY

jet(s)

One lepton Dilepton, 3L

Njet~ 0

direct

tau, di-tau

��

Njet〜2

€

˜ g g ˜ , ˜ g q ˜

€

χ ˜

LSP/NLSP

Colored sector EW sector

Photon(s)

€

R /

Multi-leptons+(jets)+ (mE_T)

Exotic particle Heavy Stable charged track

(stau,R-hadron) TOF in MS, Hcal

Kink/Disappearing track(chargino, stau)

R-hadron Stop in Hcal or mE_T

NLSP metastable or LSP/LL g ˜

LSP�unsable

t,  b 

Exotic signal�

Standard mE

_T

signal�

General MSSM�

General MSSM � General , Small m0�

GMSB, large tanβ�

GMSB�

B-jet(s)�

€

q ˜ q ˜

Displaced Vertex

Lifetime�

100μ�

10 cm�

>10 m�

carried by LSP�

トポロジーを物理でわけてみると

General�

high jet multi (Long Cascade) �

125GeVだと思うと

1. おまけがある

2. Aがfull mixing

3. 重いSUSY��

(24)

5B� SUSY with Exotic signature ��

(1) AMSB Wino LSP chargino life cτ= 1-10 cm Wino Ω<<1 (2) GMSB stau NLSP stable in detector or decay in ID Gravitino DM (3) SPLIT SUSY (m0>1000TeV) gluino → R-hadron

(4) R-parity violation If coupling is small displaced vertex

Signatures ��

Motivation �

(A) Heavy charged particles (GMSB stau, R-hadron ) (A1) dE/dx energy loss in the semiconductor , (A2) TOF information in Cal. or muon system (β< 1) (B) Decay in flight (AMSB wino, GMSB stau )

(B1) Kink/Disappearing track in the continuous tracking system (ATLAS)

(B2) neutralino decay with long-life displaced vertex is found

(C) stau and R-hadron( both neutral and charged) stop in the dense material (Hadron calorimeter) dedicated trigger is necessary to catch decay.�

heavy slow particles cτ >> detector size

kink or disappearing track cτ ~ detector size

β<1�

no mET signature should be covered �

methods as function of lifetime�

48 Displaced

Vertex dE/dx in Pixel

�� Kink /

Disappearing dE/dx in TRT

� Time of

Flight In Calorimeter

�

Time Of Flight In Muon Spectrometer

Stop in Calorimeter

�

RPV� ü ü

AMSB� ü ü

Stau LL ü ü ü ü ü

R-had� ü ü ü ü

cτγ� 100mm� 1000mm�

ATLAS� CMS�

Vertex� 0.1mm� 0.1mm�

Si (dE/dx)� 5-10cm� 5-100cm�

TRT� 50-100cm� No�

Hcal� 2-4m (Δ t~1nsec)� 1.5-2.5m�

μ � 5-10m(Δ t~1nsec)� 4-6m�

Hadronic calorimeter Fe or Brass Depth 1m�time resolution 〜1nsec�

Radius of each detector �

0.1mm� ∞�

★� ★�

?�

★�

(25)

(A1) dE/dx in Si tracker �

K� P�

π�

e�

Ionization energy loss dE/dX ~1/β

²

We can use this information to search for heavy stable particles.

D�

49�

Pi is the probability

for a minimum–ionizing particle (MIP) to produce a charge smaller or equal to the i–th

charge measurement for the observed path length in the detector�

(A2) TOF information using muon�

�drift time = TDC output time - T

₀

(flight time from IP)

�drift circle = function(drift time) Then the position is determined.

But β=1 is assumed for this calculation.

For the particle with β<1, drift circle become wrong.

Then the chi^2 becomes worse, since the calculated drift is worse.

T0 is fitted to obtain best chi^2

β＝0.3-0.95�

β resolution ~ 7%

(26)

(A1) dE/dx in ID + (A2) muon TOF (I) �

PT>50GeV Ias>0.05 1/β> 1.05

�

Data 72079 events

BG 88010+- 8800(sys) event

BG is estimated assuming that PT, dE/dx and 1/β are independent

�

314GeV is excluded (95%CL) for stable stau.

direct production�

g�

q�

q� -� wino�

wino�

Wino Pair (+-, +0) productions have large cross-section (factor 1000) and also high PT jet (ISR)

is expected since LHC is gluon quark collider. �

Monojet topology + Wino signal is signature�

Proton�

52�

Anomaly Mediated SUSY Breaking Long-lived ch1�

BUT the similar SM process gg->qZ -> q νν�(monojet) has large cross-section:

We need additional signatures of AMSB to reduce this BG process. �

Gluino is heavy and cross-section

@7-8 TeV is small.

On the other hand, Chargino is still light�

（Gravitino ~ 50TeV)�

Wino�

Bino gluino�

Bino:Wino:gluino ~ 3:1:7 �

AMSB is one of the simplest & promising � model in which SUSY breaking is mediated by quantum loop �

(27)

Chargino is Long-Lived �

Wino is LSP/NLSP

Δm(wino

⁺

- wino

⁰

)~ 150-170MeV Predictable and lifetime cτ~O(3 cm) Charged Wino decays in ID:

�

53�

Decay in TRT (ATLAS has continuous tracking)�

sinc e c τγ ~20cm -1m

-> Kink t rack i s obs erve d in

TRT

neutralino

chargino

soft pion missing Et

This is the Simulated Events�

5A：超対称性探索 with mET