light stop in precise top sample - university of wisconsin ...wangkai/lanzhou.pdfhiggs-likeíp!...
TRANSCRIPT
Light Stop in Precise Top Sample
ãããÔÔÔ
Y_'fY_—„i⌃-√
08/03/2013pfi
�\⇧⇢Nf\� ÆÆ�¯ó˝�ãO⁄�1˝�
hep-ph/1308.xxxx
Higgs-likeíP�!HiggsíP
Event display of a H ! e+e�µ+µ� candidate event with M4` = 122.6(123.9) GeV without (with) Z mass
constraint. The masses of the lepton pairs are 87.9 GeV and 19.6 GeV. The event was recorded by ATLAS on
18-Jun-2012, 11:07:47 CEST in run number 205113 as event number 12611816. Muon tracks are colored red,
electron tracks and clusters in the LAr calorimeter are colored green. The larger inset shows a zoom into the
tracking detector. The smaller inset shows a zoom into the vertex region, indicating that the 4 leptons originate from
the same primary vertex. (Courtesy: ATLAS, Collaboration)
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
{Higgs !Ö˘
51 Lepton-Photon, 24–29 June, 2013 Andreas Hoecker — Searches for Supersymmetry at Colliders
ATLAS deeply mines SUSY signatures & models
51 Model e, µ, �, � Jets Emiss
T
�L dt[fb�1] Mass limit Reference
Incl
usi
veS
ea
rch
es
3rd
ge
n.
gm
ed
.3r
dg
en
.sq
ua
rks
dir
ect
pro
du
ctio
nE
Wd
ire
ctL
on
g-l
ive
dp
art
icle
sR
PV
Oth
er
MSUGRA/CMSSM 1 e,µ 3-6 jets Yes 20.3 any m(q) ATLAS-CONF-2013-0621.2 TeVg
MSUGRA/CMSSM 0 7-10 jets Yes 20.3 any m(q) ATLAS-CONF-2013-0541.1 TeVg
qq, q�q�01 0 2-6 jets Yes 20.3 m(�
01)=0 GeV ATLAS-CONF-2013-047740 GeVq
g g , g�qq�01 0 2-6 jets Yes 20.3 m(�
01)=0 GeV ATLAS-CONF-2013-0471.3 TeVg
g g , g�qq�±1�qqW ±�01 1 e,µ 3-6 jets Yes 20.3 m(�
01)<200 GeV, m(�
±)=0.5(m(�
01 )+m(g )) ATLAS-CONF-2013-0621.18 TeVg
g g�qqqq��(��)�01�
01 2 e,µ (SS) 3 jets Yes 20.7 m(�
01)<650 GeV ATLAS-CONF-2013-0071.1 TeVg
GMSB (� NLSP) 2 e,µ 2-4 jets Yes 4.7 tan�<15 1208.46881.24 TeVg
GMSB (� NLSP) 1-2 � 0-2 jets Yes 20.7 tan� >18 ATLAS-CONF-2013-0261.4 TeVg
GGM (bino NLSP) 2 � 0 Yes 4.8 m(�01)>50 GeV 1209.07531.07 TeVg
GGM (wino NLSP) 1 e, µ + � 0 Yes 4.8 m(�01)>50 GeV ATLAS-CONF-2012-144619 GeVg
GGM (higgsino-bino NLSP) � 1 b Yes 4.8 m(�01)>220 GeV 1211.1167900 GeVg
GGM (higgsino NLSP) 2 e, µ (Z ) 0-3 jets Yes 5.8 m(H)>200 GeV ATLAS-CONF-2012-152690 GeVg
Gravitino LSP 0 mono-jet Yes 10.5 m(g )>10�4 eV ATLAS-CONF-2012-147645 GeVF1/2 scale
g�bb�01 0 3 b Yes 20.1 m(�
01)<600 GeV ATLAS-CONF-2013-0611.2 TeVg
g�tt �01 0 7-10 jets Yes 20.3 m(�
01) <200 GeV ATLAS-CONF-2013-0541.14 TeVg
g�tt �01 0-1 e,µ 3 b Yes 20.1 m(�
01)<400 GeV ATLAS-CONF-2013-0611.34 TeVg
g�bt �+1 0-1 e,µ 3 b Yes 20.1 m(�
01)<300 GeV ATLAS-CONF-2013-0611.3 TeVg
b1b1, b1�b�01 0 2 b Yes 20.1 m(�
01)<100 GeV ATLAS-CONF-2013-053100-630 GeVb1
b1b1, b1�t�±1 2 e,µ (SS) 0-3 b Yes 20.7 m(�
±1 )=2 m(�
01) ATLAS-CONF-2013-007430 GeVb1
t1 t1(light), t1�b�±1 1-2 e,µ 1-2 b Yes 4.7 m(�
01)=55 GeV 1208.4305, 1209.2102167 GeVt1
t1 t1(light), t1�Wb�01 2 e,µ 0-2 jets Yes 20.3 m(�
01) =m(t1)-m(W )-50 GeV, m(t1)<<m(�
±1 ) ATLAS-CONF-2013-048220 GeVt1
t1 t1(medium), t1�b�±1 2 e,µ 0-2 jets Yes 20.3 m(�
01)=0 GeV, m(t1)-m(�
±1 )=10 GeV ATLAS-CONF-2013-048150-440 GeVt1
t1 t1(medium), t1�b�±1 0 2 b Yes 20.1 m(�
01)<200 GeV, m(�
±1 )-m(�
01 )=5 GeV ATLAS-CONF-2013-053150-580 GeVt1
t1 t1(heavy), t1�t�01 1 e,µ 1 b Yes 20.7 m(�
01)=0 GeV ATLAS-CONF-2013-037200-610 GeVt1
t1 t1(heavy), t1�t�01 0 2 b Yes 20.5 m(�
01)=0 GeV ATLAS-CONF-2013-024320-660 GeVt1
t1 t1(natural GMSB) 2 e, µ (Z ) 1 b Yes 20.7 m(�01)>150 GeV ATLAS-CONF-2013-025500 GeVt1
t2 t2, t2�t1 + Z 3 e, µ (Z ) 1 b Yes 20.7 m(t1)=m(�01)+180 GeV ATLAS-CONF-2013-025520 GeVt2
�L,R�L,R, ����01 2 e,µ 0 Yes 20.3 m(�01)=0 GeV ATLAS-CONF-2013-04985-315 GeV�
�+1 ��1 , �
+1���(��) 2 e,µ 0 Yes 20.3 m(�
01)=0 GeV, m(�, �)=0.5(m(�
±1 )+m(�
01 )) ATLAS-CONF-2013-049125-450 GeV�±
1
�+1 ��1 , �
+1���(��) 2 � 0 Yes 20.7 m(�
01)=0 GeV, m(�, �)=0.5(m(�
±1 )+m(�
01)) ATLAS-CONF-2013-028180-330 GeV�±
1
�±1 �02��L��L�(��), ���L�(��) 3 e,µ 0 Yes 20.7 m(�
±1 )=m(�
02), m(�
01)=0, m(�, �)=0.5(m(�
±1 )+m(�
01 )) ATLAS-CONF-2013-035600 GeV�±
1 , �02
�±1 �02�W ��01Z ��
01 3 e,µ 0 Yes 20.7 m(�
±1 )=m(�
02 ), m(�
01)=0, sleptons decoupled ATLAS-CONF-2013-035315 GeV�±
1 , �02
Direct �+1 ��1 prod., long-lived �
±1 0 1 jet Yes 4.7 1<�(�
±1 )<10 ns 1210.2852220 GeV�±
1
Stable, stopped g R-hadron 0 1-5 jets Yes 22.9 m(�01)=100 GeV, 10 µs<�(g)<100 s ATLAS-CONF-2013-057857 GeVg
GMSB, stable � 1-2 µ 0 - 15.9 5<tan�<50 ATLAS-CONF-2013-058385 GeV�
Direct �� prod., stable � or � 1-2 µ 0 - 15.9 m(�)=m(�) ATLAS-CONF-2013-058395 GeV�
GMSB, �01��g , long-lived �
01 2 � 0 Yes 4.7 0.4<�(�
01)<2 ns 1304.6310230 GeV�0
1
�01�qqµ (RPV) 1 µ 0 Yes 4.4 1 mm<c�<1 m, g decoupled 1210.7451700 GeVq
LFV pp��� + X , ���e + µ 2 e,µ 0 - 4.6 ��311=0.10, �132=0.05 1212.12721.61 TeV��LFV pp��� + X , ���e(µ) + � 1 e,µ + � 0 - 4.6 ��311=0.10, �1(2)33=0.05 1212.12721.1 TeV��
Bilinear RPV CMSSM 1 e,µ 7 jets Yes 4.7 m(q)=m(g ), c�LSP<1 mm ATLAS-CONF-2012-1401.2 TeVq, g
�+1 ��1 , �
+1�W �
01, �
01�ee �µ, eµ�e 4 e,µ 0 Yes 20.7 m(�
01)>300 GeV, �121>0 ATLAS-CONF-2013-036760 GeV�±
1
�+1 ��1 , �
+1�W �
01, �
01����e , e��� 3 e,µ + � 0 Yes 20.7 m(�
01)>80 GeV, �133>0 ATLAS-CONF-2013-036350 GeV�±
1
g�qqq 0 6 jets - 4.6 1210.4813666 GeVg
g�t1t, t1�bs 2 e,µ (SS) 0-3 b Yes 20.7 ATLAS-CONF-2013-007880 GeVg
Scalar gluon 0 4 jets - 4.6 incl. limit from 1110.2693 1210.4826100-287 GeVsgluon
WIMP interaction (D5, Dirac �) 0 mono-jet Yes 10.5 m(�)<80 GeV, limit of<687 GeV for D8 ATLAS-CONF-2012-147704 GeVM* scale
Mass scale [TeV]10�1 1�
s = 7 TeVfull data
�s = 8 TeV
partial data
�s = 8 TeVfull data
ATLAS SUSY Searches* - 95% CL Lower LimitsStatus: LP 2013
ATLAS Preliminary�L dt = (4.4 - 22.9) fb�1
�s = 7, 8 TeV
*Only a selection of the available mass limits on new states or phenomena is shown. All limits quoted are observed minus 1� theoretical signal cross section uncertainty.
Nat
ura
l SU
SY
Incl
. se
arch
es
LLP
+ RPV
Exte
nded
MSS
M
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
'ã:P˘û:/�*QCD:h!
:¯í\(Ão-˚~·˜: 1 out of 10
8
ÿpT Jet pT > 120 GeV:'(œÓ�Ô¡*⌘˝œ: ��ET > 100 GeV:ói( –®fdÀÑ{P�IP: e±, µ±, �: �R
!ßvπ: b-tagging: b is from gluon splitting, „∞i⌃
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
Äv�: Gluino-binoT�nmBinoói(
Í˝⇢«Monojet plus ��ETe˚~
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
Äv�:Stop-binoT�nmBinoói(
Í˝⇢«Monojet plus ��ETe˚~
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
Tri-lepton+�˚~�±1
42 Lepton-Photon, 24–29 June, 2013 Andreas Hoecker — Searches for Supersymmetry at Colliders
-1 = 9.2 fbint
= 8 TeV, LsCMS Preliminary
[GeV]missTE
50 100 150 200
even
ts /
50 G
eV
01
2345
67
[GeV]missTE
50 100 150 200
even
ts /
50 G
eV
0
1
2
3
4
5
[GeV]missTE
50 100 150 200
even
ts /
50 G
eV
0
0.5
1
1.5
2
2.5
[GeV]missTE
50 100 150 200
even
ts /
50 G
eV
0
1
2
3
4
5
[GeV]missTE
50 100 150 200
even
ts /
50 G
eV
02468
10121416
[GeV]missTE
50 100 150 200
even
ts /
50 G
eV
00.5
11.5
22.5
33.5
44.5
[GeV]missTE
50 100 150 200
even
ts /
50 G
eV
010203040506070
[GeV]missTE
50 100 150 200
even
ts /
50 G
eV
050
100150200250300350400
[GeV]missTE
50 100 150 200
even
ts /
50 G
eV
0
5
10
15
20
25
>160
GeV
TM
<75 GeV-l+lM <105 GeV-l+l75 GeV<M >105 GeV-l+lM
<160
GeV
T12
0 G
eV<M
<120
GeV
TM
Channels:e
±
e±eµ
±
e±ee
±
µ±µµ
±
µ±µ
DataZZ
*γZWZNon-promptRare SM
uncertaintyTotal bkg
Backgrounds dominated by diboson processes
MET in signal regions with e+e�, µ+µ� and third light lepton [GeV]02χ∼
= m±
1χ∼
m100 200 300 400 500 600 700
[G
eV]
0 1χ∼m
0
200
400
600
800LEP2 slepton limitLEP2 chargino limit
)=0.5)-l+l, BF(Ll~, ( ±
1χ∼ 0
2χ∼ → pp
)=1)-l+l, BF(Rl~, ( ±
1χ∼ 0
2χ∼ → pp
, BF(WZ)=1)l~, ( no ±
1χ∼ 0
2χ∼ → pp
)=1)-l+l, BF(Ll~, ( -
1χ∼ +
1χ∼ → pp
-1 = 9.2 fbint = 8 TeV, LsCMS Preliminary
01χ∼
+ 0.5m±
1χ∼
= 0.5ml~ m
01χ∼ > m
±1χ∼ = m
02χ∼ m
Searches for “Natural” SUSY scenarios
Electroweak neutralino, chargino and slepton pair production
Most recent CMS references (8 TeV): PAS-SUS-12-022 Most recent ATLAS references (8 TeV): ATLAS-CONF-2013-049, ATLAS-CONF-2013-036,
ATLAS-CONF-2013-035, ATLAS-CONF-2013-028
Associated chargino-neutralino production (in particular in the WZ+MET final state) benefits from combined analysis of 2 and 3 leptons as featured by CMS including also tau leptons
�±1
�02
˜�
˜�
p
p
�
�
�01
�
�
�01
CM
S P
AS
-SU
S-1
2-02
2
Backgrounds dominated by diboson processes
�±1
�02
W
Zp
p
�01
�
�
�01
�
�
Heavy slepton case
[GeV]1±r¾,
20r¾
m100 150 200 250 300 350 400
[GeV
]0 1r¾
m
0
50
100
150
200
250
300
01r¾
< m
02r¾m
Z =
m1
0r¾
- m2
0r¾m
10r¾ = 2m
20r¾m
02
r¾ = m±
1r¾m
10
r¾ (*) Z10
r¾ (*) WA 02
r¾ ±1
r¾
ATLAS Preliminary=8 TeVs, -1 L dt = 20.7 fb0
)theorySUSYm1 ±Observed limit (
)expm1 ±Expected limit (
= 8 TeVs, -1ATLAS 13.0 fbAll limits at 95% CL
Much harder scenario – great success to have sensitivity
CM
S P
AS
-SU
S-1
2-02
2
“τ enriched”
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
{Stop(Natural SUSY)
34 Lepton-Photon, 24–29 June, 2013 Andreas Hoecker — Searches for Supersymmetry at Colliders
Searches for “Natural” SUSY scenarios
Direct stop pair production — grand summary for top+LSP
˜t
˜tp
p
�01
t
�01
t
[GeV]1t
~m200 300 400 500 600 700
[GeV
]10 r¾
m
0
50
100
150
200
250
300
35010
r¾ t A1t~0L,
10
r¾ t A1t~1L,
10
r¾ t A1t~2L,
10
r¾ W b A1t~2L,
10
r¾+mt
< m
1t~m
10
r¾
+ m
W
+ m
b
< m
1t~m
10
r¾ W b A1t~ /
10
r¾ t A1t~ production, 1t
~1t
~ Status: LHCP 2013
ATLAS Preliminary
-1 = 4.7 fbintL -1 21 fb5 intL10
r¾W b -1 = 20 fbintL
Observed limits )theomObserved limits (-1 Expected limits
0L CONF-2013-024
=8 TeVs -1 = 20 - 21 fbintL =7 TeVs -1 = 4.7 fbintL
1L CONF-2013-037-2L CONF-2013-048
0L [1208.1447]1L [1208.2590]2L [1209.4186]-
[GeV]t~ m200 300 400 500 600 700 800
[G
eV]
10 χ∼m
0
50
100
150
200
250
300
350
400BDT analysis
01χ∼ t → t~, t~ t~ →pp Observed (unpolarized top)
Observed (right-handed top)Observed (left-handed top)
-1Ldt = 19.5 fb∫ = 8 TeV, sCMS Preliminary
t
= m
01χ∼
- mt~mW
= m
01χ∼
- mt~m
0 ~ ~
CM
S: P
AS
-SU
S-1
3-01
1
Most recent CMS references (8 TeV): PAS-SUS-13-011, PAS-SUS-13-003, 1303.2985
Exclusion of m(t1) < ∼660 GeV for massless LSP; exclusion up to m(χ1 ) ∼ 250 GeV
Most recent ATLAS references (8 TeV): ATLAS-CONF-2013-053, ATLAS-CONF-2013-048, ATLAS-CONF-2013-037, ATLAS-CONF-025, ATLAS-CONF-2013-024
< 30 GeV dependence on L/R stop admixture
(ãǢ p et alåN0õ et al)
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
2b + ` + nj +��ET
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
�(7 TeV)tt = 162 pb ± 4%
10-2
10-1
1
10
10 2
150 175 200 225 250 275 300Mt (GeV)
m (p
b)
�(7 TeV)tt⇤
(Mt = 200) ' 6 pb
�(Tevatron)tt⇤
(Mt = 200) ' 0.2 pb
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
v8K¡NÕ���å˘ÜèÑ•J
v8K/�ÕÑ˙,íP
mt = 173.2 GeV¯8K �t � ⇤QCD
æn¿åÆpQCD
NLL
NLO + NNLL
0 0.2 0.4 0.6 0.8 10
2
4
6
8
10
12
14
d�/d
�t[pb]
�t
�s = 1.96 TeV
NLL
NLO + NNLL
0 0.2 0.4 0.6 0.8 10
100
200
300
400
d�/d
�t[pb]
�t
�s = 7 TeV
Figure 11: Distributions d�/d�t at the Tevatron (left) and LHC (right).
NLO + NNLL
CDF data
0 200 400 600 800 1000 12000.01
0.1
1
10
100
M [GeV]
d�/d
M[fb/G
eV
]
�s = 1.96 TeV
NLO + NNLL
CDF data
360 380 400 420 440 460 480 5000
10
20
30
40
50
60
70
80
M [GeV]
d�/d
M[fb/G
eV
]
�s = 1.96 TeV
Figure 12: Comparison of the RG-improved predictions for the invariant mass spectrum with
CDF data [9]. The value mt = 173.1 GeV has been used. No fit to the data has been performed.
very useful distribution d�/d�t, with �t defined as in (4). A simple change of variables yields
d�
d�t=
2mt�t
(1 � �2t )
32
d�
dM. (106)
The resulting spectra for the Tevatron and LHC, obtained using RG-improved perturbation
theory, are shown in Figure 11. As before, the distributions are normalized such that the area
under the curves corresponds to the total cross section. Recall that the physical meaning of
the variable �t is that of the 3-velocity of the top quarks in the t¯t rest frame. The distributions
show that the dominant contributions to the cross section arise from the region of relativistic
top quarks, with velocities of order 0.4–0.8 at the Tevatron and 0.5–0.9 at the LHC. We will
come back to the significance of this observation in the next section.
In Figure 12, we compare our RG-improved prediction for the invariant mass spectrum
36
In order to analyze the electroweak O!!2s!" terms, it
is useful to separate the QED contributions involvingphotons from the weak contributions with Z bosons. Inthe QED sector we obtain the O!!2
s!" contributions toN from three classes of partonic processes: q !q ! t!t,q !q ! t!tg and q !q ! t!t". The first case is the virtual-photon contribution, which can be obtained from theQCD analogue, namely, the O!!3
s" interference of boxand tree-level amplitudes, by substituting successively
each one of the three internal gluons by a photon, asdisplayed in Fig. 4.The essential differences between the calculation of the
O!!3s" and of QED O!!2
s!" terms are the coupling con-stants and the appearance of the SU!3" generators in thestrong vertices. Summing over color in the final state andaveraging in the initial state we find for the virtual contri-butions to the antisymmetric cross section the followingratio,
jMt!tj2O!!2s!";asym
jMt!tj2O!!3s ";asym
#2Re!Mt!t
O!!"Mt!t $O!!2
s ""asym % 2Re!Mt!tO!!s"M
t!t $O!!s!""asym
2Re!Mt!tO!!s"M
t!t $O!!2
s ""asym#
Ft!tQED!!s;!; Qt; Qq"
Ft!tQCD!!s"
(8)
that can be expressed in terms of two factors Ft!tQED and Ft!t
QCD depending only on coupling constants and color traces,
Ft!tQCD # g6s
9#AD#BF#EC Tr!tAtBtC"
!1
2Tr!tDtEtF" % 1
2Tr!tDtFtE"
"# g6s
16 & 9 d2; (9a)
Ft!tQED # nt!t
#g4se
2QqQt
9#AC#BD Tr!tAtB"Tr!tCtD"
$# 6g4se
2
9QtQq: (9b)
Ft!tQCD contains two different color structures and the result
depends on d2 # dABCdABC # 403 , which arises from
Tr!tAtBtC" # 14 !ifABC % dABC". Ft!t
QED instead depends onthe charges of the incoming quarks (Qq) and of the top-quark (Qt), together with nt!t # 3 corresponding to Fig. 4.
In a similar way, also the real-radiation processes q !q !t!tg and q !q ! t!t" (Figs. 5 and 6) can be evaluated startingfrom the result obtained for q !q ! t!tg in the QCD case andsubstituting successively each gluon by a photon, yieldingthe ratios
jMt!tgj2O!!2s!";asym
jMt!tgj2O!!3s ";asym
#2Re!Mt!tg
O!! %%%%!s
p "Mt!tg $O!!s
%%%%!s
p ""asymjMt!tg
O!!s%%%%!s
p "j2
asym
#Ft!tgQED!!s;!; Qt; Qq"
Ft!tgQCD!!s"
; (10)
jMt!t"j2O!!2s!";asym
jMt!tgj2O!!3s ";asym
#jMt!t"
O!!s%%%!
p "j2
asym
jMt!tgO!!s
%%%%!s
p "j2
asym
#Ft!t"QED!!s;!; Qt; Qq"
Ft!tgQCD!!s"
: (11)
Ft!tgQCD, F
t!tgQED and Ft!t"
QED are related to Ft!tQCD, F
t!tQED in the
following way,
Ft!tgQCD # Ft!t
QCD; Ft!tgQED # 2
3Ft!tQED;
Ft!t"QED # 1
3Ft!tQED; Ft!t
QED # Ft!tgQED % Ft!t"
QED: (12)
This guarantees the cancellation of the IR singularitiesstemming from the virtual contributions.The O!!2
s!" antisymmetric term from q !q ! t!tg comesfrom the interference of q !q ! g ! t!tg (Fig. 3) and q !q !" ! t!tg (Fig. 5). It can be obtained from the correspondingQCD result with the replacement of one gluon by a photonand the right couplings, as done in the case of q !q ! t!t. Theonly difference is the number of gluons to be replaced: in
FIG. 5. Real gluon emission from photon exchange diagrams.
FIG. 4. Different ways of QED—QCD interference atO!!2
s!".
ELECTROWEAK CONTRIBUTION TO THE TOP QUARK . . . PHYSICAL REVIEW D 84, 093003 (2011)
093003-3pÿ¿åHiggs:6
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
v8KÑæ∆Kœ�Higgs:6Ñ¿åv8KåWíPÑ(œ˝eêé15˘'Í—4:⇥\:�ÕÑ˙,íP�v8K�Goldstone(µ⌘Å�W ) :&�⇥
mb ⌧ mt
Wµ⌘Å� ✏0 ⇠ kµ/mW
✏⇤0ubL�µut ' mt
mWubLut
F0 =
�(t ! bW+0 )
�(t ! bW+0 ) + �(t ! bW+
+ ) + �(t ! bW+� )
' 70%
F� ' 30%, F+ ' 0
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
KœÅ�Ñπ’
1
�
d�
d cos ✓⇤=
3
8
FR(1 + cos ✓⇤)2 +
3
8
FL(1 � cos ✓⇤)2 +
3
4
F0 sin
2 ✓⇤
(p`T¯s')
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
✓ÑI˜öI
the angle between the momentum direction of chargedlepton from the W-boson decay and the reversedmomentum direction of the b quark from top-quark decay ,both boost into the w-boson rest framethe angle between the charged lepton three-momentum inthe W rest frame and the the W momentum in the top restframethe angle between the direction of the charged lepton andthe reversed direction of the top quark ,both in the restframe of the W bosonthe angle between the momentum direction of the chargedlepton from the W-boson decay and reversed momentumdirection of the b quark from top-quark decay
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
WÅ�Kœ�Higgs:6
22 M. Aldaya
W polarization (2.2 fb-1) Anomalous contributions to the tWb vertex change the probabilities of the W helicity states
CMS-PAS TOP-11-020
! In SM: 3 possible W helicity states: F0 (longitudinal) ~ 0.70, FL (left) ~ 0.30, FR (right) ~ 0
Angle between charged lepton and top direction in W rest frame
! Helicity fractions extracted from maximum likelihood fit:
• 1 isolated high-pT µ, ! 4 jets, ! 1 b-tag • Kinematic fit to reconstruct ttbar system
! Good agreement with SM ! Similar precision as previous measurements (Tevatron, ATLAS)
! Measure sensitive variable, cos("*), in muon+jets channel:
F0
FR FR
XXVI Rencontres de la Vallee d'Aoste, 01.03.12
Feb’12
LHC Combination
FL = 0.359 ± 0.021(stat.) ± 0.028(syst.)F0 = 0.626 ± 0.034(stat.) ± 0.048(syst.)
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
Stop˚fl
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
{[�gV11˜tL + ytV12˜tR]
¯bPR + ybU12˜tL¯bPL}�+c1
Natural SUSY in MSSM ! Large A (50% Left-Right)But NMSSM gives more freedom.
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
ØWino
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
ØHiggsino
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
ãã ÷ v8KÕ˙(�2)
No b-tagging~p⌫
T = ��~pT
Scan p⌫z : -3500 GeV –3500 GeV
�2=
(M`⌫ja � mt)2
�2t
+
(Mjbjcjd � mt)2
�2t
+
(M`⌫ � mW )
2
�2W
+
(Mjcjd � mW )
2
�2W
mt = 172.5 GeV, mW = 80.4 GeV, �t = 14 GeV, �W = 10 GeV
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
cos ✓
e, bˆ(œÅP
pe · pb ' 1
2
M2eb
cos ✓⇤e+ =
EeEb � pe · pb
| pe || pb | = �1 +
pe · pb
EeEb= �1 +
M2eb
2EeEb
⌥∆!ãv8Kpÿ�W(√˚- Eb = (m2t � m2
W )/2mW ,E` = mW /2
cos ✓⇤ = �1 +
2M2eb
m2t � m2
W
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
cos ✓:Correct vs. Fake
ecos
-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1
Even
ts
0
200
400
600
800
1000
1200
1400
is right-handed1 and t2mu>>M
Real Combination
Combination2r
ecos
-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1Ev
ents
0
200
400
600
800
1000
is right-handed1 and t2mu<<M
Real Combination
Combination2r
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
Correct vs. Fake
blM
0 50 100 150 200 250
Even
ts
0
1000
2000
3000
4000
5000
is right-handed1 and t2mu<<M
Real Combination
Combination2r
blM
0 50 100 150 200 250Ev
ents
0
1000
2000
3000
4000
5000
is right-handed1 and t2mu>>M
Real Combination
Combination2r
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
Correct vs. Fake
lE
0 20 40 60 80 100 120 140
Even
ts
0
2000
4000
6000
8000
10000
12000
is right-handed1 and t2mu<<M
chargino rest frame
fake W rest frame
lE
0 20 40 60 80 100 120 140Ev
ents
0
2000
4000
6000
8000
10000
12000
is right-handed1 and t2mu>>M
chargino rest frame
fake W rest frame
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
Correct vs. Fake
bE
0 50 100 150 200 250 300
Even
ts
0
10000
20000
30000
40000
50000
is right-handed1 and t2mu<<M
chargino rest frame
fake W rest frame
bE
0 50 100 150 200 250 300Ev
ents
0
10000
20000
30000
40000
50000
is right-handed1 and t2mu>>M
chargino rest frame
fake W rest frame
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
Correct vs. Fake
lEbE
0 20 40 60 80 100 120 140
Even
ts
0
2000
4000
6000
8000
10000
is right-handed1 and t2mu<<M
chargino rest frame
fake W rest frame
lEbE
0 20 40 60 80 100 120 140Ev
ents
0
2000
4000
6000
8000
10000
is right-handed1 and t2mu>>M
chargino rest frame
fake W rest frame
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
�2åv8K(œ ÷
*ecos-1 -0.5 0 0.5 1
num
ber o
f eve
nts
0
2000
4000
6000
8000
10000
=200t-fake m2r*-L 1t~1
t~ µparton_level M2>>
*ecos-1 -0.5 0 0.5 1
num
ber o
f eve
nts
0
5000
10000
15000
20000
25000
=400t-fake m2r*-L 1t~1
t~ µparton_level M2>>
*ecos-1 -0.5 0 0.5 1
num
ber o
f eve
nts
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
=1000t-fake m2r*-L 1t~1
t~ µparton_level M2>>
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample
”∫
vÜ⌥œv8K(Stop)êœ(v8K˘˚fl-ÑÔ˝�—∞‡:fakeÕ˙ÑqÕ�Çú g∞ ÑKœWÅ�Ñπ’�⌥œv8Kh∞:ÊKÅ�ÑW�v�⇢À;´íd⇥
ecos
-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1
Even
ts
0
200
400
600
800
1000
1200
1400
is right-handed1 and t2mu>>M
Real Combination
Combination2r
ecos
-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1
Even
ts
0
200
400
600
800
1000
is right-handed1 and t2mu<<M
Real Combination
Combination2r
""'∂�
YYY___'''fffYYY___———„„„iii⌃⌃⌃---√√√ãããÔÔÔ Light Stop in Precise Top Sample