“SUSY” はどうやって決まっていくかmSUGRA reach at ATLAS & CMS (1 fb-1)
A0 = 0, µ > 0, tan! = 10, 5" contours (incl. systematics)
can study
leptons(ATLAS):
but the! You
Assumeduncertainties•!
QCD: 50%
parameter
region is rather small
1 fb-1!

tt, V+j: 20%

1 fb-1!

Beware:!

!

SUSY Searches at the LHC-14-

Different significancedefinitions!
CMS: syst. uncertainties
estimated for 10 fb-1
(except 0-lepton: 1 fb-1)
Oleg Brandt, Univ. of Oxford

n100.ge.1 n50 ge 4

ETmiss>0.2 Meff

ST>0.2, del phi cut, e mu vetoSU3 squarks 630GeV, gluino 717GeV, LSP 117 GeV
SU2 gluino 856 GeV, LSP 103 GeV ass others are heavy
SU4 squark400 GeV, gluino 413, LPS 59, very light stop

MTの方向assumemostly
BGC

signal region

assume backgroundin this region as
B*C/A

background regionAB(lepton +missing is consistent with W）
missing momentum

summary of MT method*background over estimate.
*correction assuming background does not exact for large mt region.
*ttbar better controled by requiring hadronic top tag.
* need better idea

Inclusive→exclusive• 初期

BG を実験的に estimate. Signal はBG の残り• Signal の kinematical structure が backgroundの上にでて初めて、本当になにかが起こっているということがわかる。

• Discovery というのは基本的に exclusive• (>4j) > (jets+ 1 lepton) > (jets + 2lepton)•(>4j)<(jets + 1lepton) < (jets + 2lepton)

Jet でできることを探す

MT2• 見えない運動量+ lepton -> MT 変数( W の質量をだすのに有効。）• SUSY events 見えない運動量= 2つの LSP の運動量
• visible object を２つにわけて、仮想LSP運動量とMT をくむ(和は見えない運動量となるようにした)• ２つのMT の最大値の すべてのLSP 運動量についての最小値• 新しい Kinematical variable -> 新しい 物理量がだせる。

Figure 9: mT 2 distribution with (a) mχ = 10 GeV and (b) mχ = 350
parameter point (71).

(GeV)

4 jet final state and gluino mass
Figure 8: Extreme momentum
configuration providing m
as an unbalanced solution
determination
for mχ > mχ̃01 .

1100

max
T21050

ProcessmAMSB(heavy squark)
(2)
(1)
(2)
Therefore,ppmT →>mifm>m,thoughmg̃g̃χχ̃TT is at the unconstrained minimum value,
100001mmax
T2 (g)

950

900

~

so that we have unbalanced mT 2 solution, i.e. mT 2 = (mg̃ −mχ̃01 ) + mχ for this momentum∗same unbalanced
0 m solution is obtained for the momentum configconfiguration.
Theg̃ → q̃ q → q q̄ (1)χ̃1 T 2(2)
(1)
(2)
uration with other values of mvis because those cases also give mT ≥ mT when mT
is at the unconstrained minimum. Such momentum configurations and the back-to-back
Cho et almiss2
cascadedecayinbothside.
transverse boosted ones would have a sizable |pT |, so can be used to determine mmax
T2
from real collider data.
m(GeV)
To summarize the extremal features of mT 2 for the decay of gluino pair when mq̃ > mg̃ ,the maximum of mT 2 over all events is given bygluino 3 body decay.
max!$Figure 10:
mof the trial LSP mass mχ for the AM
T 2 as a function%"2m2g̃ −(71).
m2χ̃0 " m2g̃ − m2χ̃0#11mmax(m)=++ m2χ if mχ < mχ̃01 ,χT22mg̃2mg̃
&' point in a minimal anomaly mediated SUSY-breaking (Aparameter
whichmmaxmg̃ −mχ̃01 give+ mχ if mχ > mχ̃01(70)T 2 (mχ ) =
850

800

750

700

650

050

100

150200250300350!

mg̃ = 780 GeV, mχ̃1 = 98 GeV,
asobtainedin(45)
and(47)inmore
genericcontext.
Thus, there is a level crossing of
ジェットイベントばかりでもLSPの質量が決定できる。
maxmmax
T 2 at mχ = mχ̃01 , yielding a kink structure as shown in Fig. 4(a). If such mT 2 -curve
21 subsection, thiscan be constructed from collider data, which will be examined in the next“No Sliding solution” ?
kink structure will enable us to determine the true LSP mass mχ̃01 and the gluino mass
0max

JET シグナルの問題点
平松野尻清水Alwall• Example MT2 mass reconstruction• Reconstruction steps:

41(hemisphere algorithm)• 1)Take 2 highest pT jets j1 and j2• 2) associate j3 and j4 to one for3each• 3)take combination of jets thatgives smaller mT2.

2

• Now this is it. (jet level)
Events without
Initial radiation
after matching“exclusive”

Events with Inital stateradiation “inclusiveinput gluino masstotal cross section 3pb
50000 events generated
no SUSY cut

inclusive/exclusive =1.4 for gluino pair
0.8 for squark pair

ISR is specially bad for gluino production

PT order of the additional jet• Hard and high PT additional jet is actually

dominant part of the production cross section.
Soft ISR we naively expect

All the other additonalthing that kills your end point

Why so many additional jets
• dominant process g g→ gluino gluino

1+z
Pqq ∝1−z2• quark -anti quark is small.

• + 1 jet• gluon gluon → gluon gluino gluino (lowenergy)• qg → q squark gluinoq( high energy and high luminosity, and quark
takes most of energy at the branching. )qHow to get around (better solution)• We have to realize that we are working on “5 jet system”
rather than “4 jet system”. More than half events haveadditional jets!

Proposing new step for mass reconstruction411) take the 5 highest pT jet (“five” is enoughbecause “hard emission” is perturbative)2) remove one of the jet i, and calculate“MT2(i)”5323) take minimum of MT2(i)MT2min= min MT2(i)= MT2(imin)
imin may be true ISR!

End point distribution?
parton level distribution

673.9 +/- 2.5 GeV

jet level

675.4 +/- 6.4 (imin. ge.3 )672.7+/- 3.5 (for all)• We recover end point (not much smear though
we minimized) .

教訓• ISR がでかいのは gluon gluon →SUSY pair だけ（ちなみにこの解析は NLO をやっているのと同じ）• forward だけきっても ISR はなくならない。
• gluino pair の場合: hard ISR があると思った解析が正しい。

• gluino が多段崩壊（ top など）ではさらに ISR の方がenergy がでかくなる確率が高い。（より重要性がます）• squark gluino co produciton の contamination をなんとかすべし。

MAOS• MT２に対応する仮想運動量を正しいと思って分布をだす。MT2 のエンドポイントではかなり正しいµ, one can use the s-tmaos distribution:
With kmaos!103600
400
500

350

450!10

3400

500

350

m2qq [GeV2]

450

dΓ
true
max
for (mtrue,m)and(0,Mχ
Y
T2 (0))
dsdtmaosm2qq [GeV2]

m2qq [GeV2]dΓdsdttrue450!103350
400

300

400

250

350
250

300

250

250300

しい組み合わせ300

400300

完全にparton level で正200

普通の解析をするとま300
200

200

200

150

200
200

150

150

150
100100100

1005050

100

200

300

400

5000!103600

00!103

1200
400
1000

350
300

100200

300

400

5000!103
600

00~ 2 (SUSY) [GeV2]
mq!

100

200

300

gluino 3-body decay

800m2qq [GeV2]

m2qq [GeV2]

m2q ! (SUSY) [GeV2]

450

50

50450!10

3

800

400

700

350

600

300

500

m2qq [GeV2]00

ずとれない。

100

100

450!10400

500

!1003
600

~ 2 (SUSY) [GeV2]mq!

MT2 end point のあたり
では ISR がのぞけるので

3500

400
400

350

まだましかも300
300

250

250

250
400

600
200

200

200
300

400

150

150

200
150

200
100

200

5000100

10050100200300

4005000!103600

m2q ! (UED) [GeV2]

10010000501002003004005000!103600~ 2 (UED) [GeV2]mq!

00KK-gluon 3-body decay

100200300

400500!1003
600~ 2 (UED) [GeV2]mq!

Choi et al

CSC note で気になること（SU4)n100.ge.1 n50 ge 4

ETmiss>0.2 Meff

ST>0.2, del phi cut, e mu vetoSU3 squarks 630GeV, gluino 717GeV, LSP 117 GeV
SU2 gluino 856 GeV, LSP 103 GeV ass others are heavy
SU4 squark400 GeV, gluino 413, LPS 59, very light stopSUSY contamination• 解析としては conservative (inclusive)• exclusive analysis をすれば、overlap region でもなにかあるはず。まだ使っていないものはなにか。

• MT2• gluon gluon dominated : ISR control?
• 統計的には量はあるので、なにもできないはずはな
い。

neutralino nature• LHC produce strongly interacting particle• DM is not strongly interacting.
• Exclusive analysis is important.

Checking LSP nature using( 2 jet+ETmiss) /(>4 jet +Etmiss) signature
Nojiri Sreethwong
600 GeVhigh pT jets

jetHiggsino(323GeV)
Wino(198GeV)
Bino(115GeV)

WinoBinojetsHiggsino• 2jet only + ET miss (coming from squark direct

decay into LSP ) signal means gaugino like LSPATLAS study for 2 jet signature.

plot as the function of“MT2” variable2jet +ETmiss(M1,M2,μ）=(122,230,271)

Factor 10 reductions(187,291,146)

100 GeV mass difference between Higgsno LSP and heavier inos areenough to kill all 2 jet + missing ET events.

M1<M2<μM1<μ<M2
μ<M1<M2

+Classic l l leptons

SUSY cascade decay =mass and spin, interaction
measurementssquarkgauginoquark

見えない運動量scalar lepton
leptonlepton

質量の情報
質量の情報

gauginoMass measurement using endpoints
O(10)% for LSP, O(1%) for squark at best
レプトン

レプトン

jllの不変質量分布

squarkジェットATLAS TDR

parameter determination にはhigher end points が重要
0 0
χ1 χ2 ˜lR+χ2 ˜lLχ̃i → χ̃1 Z 0
χ̃2 → ˜lR → χ̃1χ̃4 → ˜lL → χ̃1mll

0χ4

!"#$%&'()*+,"*-.%/0%"*#$%./$(*!"#$%&1"*-23*.#"*45*,'#+$)62-**!'#"%&+$*7'#/().'#,*+,"*7.0%'82/$(9*:.+;*+,"*#,20"*$<*45*,'#+$)62-*='%%*
7"0"(7*$(*&26'$.#*">"8+#*($+*$(%3**+,"*0,2#"*#028"?-2##*#0"8+6.-@*!"#'%&!'#"%&A,"*B$.(7263*$<*C5*,'#+$)62-*D.#+*
7"0"(7#*$(*0,2#"*#028";**+,"*7"(#'+3*'(*+,"*C5*='%%*7"0"(7*$(*+,"*$+,"6*">"8+#*?#0'(;*8$.0%'()*8$(#+2(+#;**2(7*#$*$(@*

Kong et al from
IPMU focus weekjet selection
j1 and j2

j gives m(j1ll) m(j2ll)

Nojiri (練習）• 標準的な選択でない方がいいかもSUSY like models

SUSY vs LHT vs UED
supersymmetry

quark （spin 1/2）⇄scalar quark (0)gauge boosn (1)gaugino（1/2)
Lihgtest neutralino(?) is stable due to R parity
Little Higgs model
quark ⇄quark partner(1/2)
gauge boson (1)gauge partner （1)Lightest gauge partner is stable due to T parity
gluon partner does not exist.
UED model

quark ⇄ level 1 quark.....
gauge boson ⇄level 1 gauge boson...

lightest level 1 KK stable, gluon KK exists.

decay pattern is similar, interactions are similar (∝gauge coupling)→test bench of spin determination(cross section, decay pattern)ジェット+lepton+SUSY

見えない運動量LHT

MSUGRAAMGM

NuHM

RpVUED

Comparing cross sections.
gluon のいない SUSY
squark squark production at 1 TeV~1 pb

cross section is about the same but
it is just coincidence.

SUSYLHTproduction process
qq̃
x Mg̃

qq

qheavy gauge bosonsq̃cross section is rather
independent to gluino massin Little Higgs model, only
weak gauge boson partner exists
but cross sections are same orderWith T channel octet exchange
cross sections is about factor 10 larger
due to T-channel KK gluon
SUSY

UED

1.3TeV

production cross section
は <1TeV classMass > cross section• cross section はとても質量に sensitive。 mass をまず決めること。

• rate = Branching ratio x cross section• Low energy Lagrangean を仮定すれば fundamental
parameter は ある程度決まっていく。どこでずれるか考えるのは大事。