Dark Matter at the LHC
description
Transcript of Dark Matter at the LHC
12/17/07Cosmological Connection at the LHC: Stau N
eutralino Coannihilation Case
Dark Matter Dark Matter at the at the LHCLHC
Bhaskar Dutta
Texas A&M University
Dark Matter at the LHC 130th Oct ’ 09
Texas Cosmology Network Meeting, UT, Austin
2
2
1CDM
+ ….
Dark Matter and SUSYDark Matter and SUSY
pbM
vann 1~~2
2
Dark Matter at the LHC
We need to observe the new layer of matter in order to establish this explanation
The signal : jets + leptons + missing ET
SUSY at the LHC
(or l+l-, )
DM
DM
Colored particles get produced and decay into weakly interacting stable particles
High PT jet
High PT jet
[mass difference is large]
The pT of jets and leptons depend on the sparticle masses which are given by models
R-parity conserving
3
(or l+l-, )
Dark Matter at the LHC
mSUGRA: Minimal ScenariomSUGRA: Minimal Scenario
4 parameters + 1 sign
du
Zdu
HHW
MA
Mm
Mm
MH/H
in of Sign :)sign(
at coupingTrilinear :
at massscalar Common :
at mass gaugino Common :
at :tan
(2)GUT0
GUT0
GUT1/2
Dark Matter at the LHC 44
Minimal Supersymmetry Standard Model has more than 100 parameters
•We may not have enough observables to establish them
•We start with a simple scenario and go to complicated cases
SUSY ModelsSUSY Models
Dark Matter Allowed RegionsDark Matter Allowed Regionstan = 40
A0 = 0, > 0
ab
c
Excluded by1)Rare B decay b s 2)No CDM candidate3)Muon magnetic moment
a
bc
m0 (
GeV
)
m1/2 (GeV)
Over-dense DM Region22
Coannihilation Region11
FP/HB Region33
Dark Matter at the LHC 55
Observables at the LHC Observables at the LHC
Mj
&Mj
Lu~
01χ~
02χ~
g~
97%
u
u
SU
SY
Mass
es
(CDM)
pT
> 40 GeV
pT > 20 GeV
ET jet > 100 G
eV
M
& pT()
1~
100%
The observables include:Z, h, W, , t, b, jet, l and missing energy
The observables are determined by the underlying physics of the model
Dark Matter at the LHC
CaseCase 1. Coannihilation Region1. Coannihilation Region
100% 1~
Lu~
01χ~
02χ~
g~
97%
u
u
SU
SY
Mass
es
(CDM)2 quarks+2 ’s
+missing energy
7
Low energy taus characterize the CA region
However, one needs to measure the model parameters to predict thedark matter content in this scenario
Dark Matter at the LHC
fTMe k/Δ
2
GeV15~5Δ 011
~~ MMM GeV15~5Δ 0
11~~ MMM
01~
1~
+ ….
Griest, Seckel ’91
Arnowitt, Dutta, Kamon,Toback’08
Determining mSUGRA ParametersDetermining mSUGRA ParametersSolved by inverting the following functions:
140tan
160
4350
5210
0
2/1
0
A
m
m
),tan,( 02/102
~01
AmmZh
1fb 10 L
1fb 50
)fb 70( %1.4
)fb 30( %2.6/1
12~
2~ 0
101
hh
),tan,,(
),(
),tan,,(
),(
002/14peak )(
eff
02/13peakeff
002/12peak
02/11peak
AmmXM
mmXM
AmmXM
mmXM
b
j
10 fb-1
Dark Matter at the LHC 88Phys.Rev.Lett.100:231802,2008.
Case 2 : Over-dense regionCase 2 : Over-dense region
1~
Lu~
01χ~
02χ~
g~
h
1χ~
m1/2=440, m0=471, tan=40, mtop=175
Re~
u
87%
10411044
500
393
181
341
114
46213%
Z91
ETmiss > 180 GeV;
N(jet) > 2 with ET > 200 GeV; ET
miss + ETj1 + ET
j2 > 600 GeV
Dark Matter at the LHC 99
N(b) > 2 with PT > 100 GeV; 0.4< Rbb < 1
DeterminingDetermining hh22
Solved by inverting the following functions:
1839tan
950
15440
50472
0
21
0
A
m
m
/
),tan,( 02/102
~01
AmmZh 1fb 1000 L
%~h/h ~~ 150ΩΩ 2201
01
)tan(
)tan(
)(
)(
00214peak )(
eff
00213peak )(
eff
0212peakeff
0211point end
A,,m,mXM
A,,m,mXM
m,mXM
m,mXM
/bb
/b
/
/jbb
1000 fb1000 fb-1-1
Dark Matter at the LHC 1010
Phys.Rev.D79:055002,2009 Dutta, Kamon,Nanopoulos etal ’09
Case 3 : Focus Point /HBCase 3 : Focus Point /HB
Prospects at the LHCProspects at the LHC: A few mass measurements are available: 2nd and 3rd neutralinos, and gluino
g~
0i
~
q~ l~ Z
ZZ
Z
m0, A0, , tan
m1/2, tan
Dark Matter at the LHC 1111
0
0
0
0
2
1
0
scMssM
ccMcsM
scMccMM
ssMcsMM
WZWZ
WZWZ
WZWZ
WZWZ
~Μ M4x4 (m1/2, , tan)
01
02
21 ~~ MMD 01
03
31 ~~ MMD g~M
)tan( 212
01
,,mZh /~
Case 4 : Non-U SUGRACase 4 : Non-U SUGRANature may not be so kind …Nature may not be so kind … Our studies have been done based on a minimal scenario (= mSUGRA). … … Let’s consider a non-universal scenario: Higgs non-universality: mHu, mHd m0
Steps:Steps:1) Reduce Higgs coupling parameter, , by increasing 2) mHu, … More annihilation (less abundance) correct values of h2
3) Find smoking gun signals Technique to calculate h2
SUGRA Models at the LHC 1212
Dark Matter at the LHC 13
Extraction of Model ParametersExtraction of Model Parameters
End-points-nonuniversalM(jW) [ ] = 714.6 GeVM(jW) [ ] = 727.3 GeV[use 2 ’s since ]M(jW)[ ] = 652.4 GeV [use Z since ]M(jW) [ ] = 738.6 GeV
22 32
0
4
10
02
We can use stop decay chainIn this case we use a b/t
We have 3 (4) parameters in the chargino-neutralino system:m1/2, , tan (m1,m2, , tan)
01
02 Z
Theory:738.8
~500 GeV
M(bW)
M(jW)
Similarly, M(tZ) =338 GeV00
3
Mt, Mj etc can also be constructed
Dark Matter at the LHC
ConclusionSignature contains missing energy (R parity conserving) many jets and leptons : Discovering SUSY should not be a problem!
Once SUSY is discovered, attempts will be made to measure the sparticle masses (highly non trivial!), establish the model and make connection between particle physics and cosmology
Different cosmologically motivated regions of the minimal model have distinct signatures.It is possible to determine model parameters and the relic density based on the LHC measurements
Dark Matter at the LHC
Work is in progress to determine non-universal model Parameters----looks promising