mSUGRAmSUGRA Signals Signals mSUGRA Signals at ...people.physics.tamu.edu/kamon/research/talk/2004/040817...August 17, 2004 mSUGRA Signals at LHC and LC 1 R. Arnowitt,1) B. Dutta,2)

August 17, 2004 mSUGRA Signals at LHC and LC 1

R. Arnowitt,1) B. Dutta,2) T. Kamon,1) V. Khotilovich,1)*

1) Department of Physics, Texas A&M University1) Department of Physics, Texas A&M University2) Department of Physics, Regina University, Canada2) Department of Physics, Regina University, Canada* Graduate Student* Graduate Student

mSUGRA Signals at LHC and LC

mSUGRAmSUGRA Signals Signals at LHC and LCat LHC and LC


SUGRA and Cosmology

A v a i l a b l e m S U G R Aparameter space with:(a) Rare decay constraints(b) Collider bounds(c) Cosmological constraints

Determination of SUSY masses in Co-annihilation region at LHC and LC

Conclusion and Future Tasks

Talk OutlineTalk Outline

We focu

s only on

the LC case

, today.


SUGRA and CosmologySUGRA and Cosmology

1. 1. SupergravitySupergravity models with models with RRparity invariance gives rise to parity invariance gives rise to a stable dark matter candidate:a stable dark matter candidate:

The lightest neutralino:The lightest neutralino:

2. This neutralino can give rise 2. This neutralino can give rise to the right amount of cold to the right amount of cold dark matter of the universe.dark matter of the universe.

3. The relic density of these 3. The relic density of these neutralinosneutralinos is given by:is given by:

∫ −><fx

~ vdx~h0

1ann

2 )(01

σΩχ

01

~χ

τ

τ

τ1~

χ10~

χ10~

τ1~

χ10~

ττ

γ

wherewhere σσannann is calculated inis calculated int e r m s o f S U S Y m o d e l t e r m s o f S U S Y m o d e l parameters.parameters.

m1/2 Common gaugino (spin=1/2) mass (GeV)m0 Common scalar (spin=0) mass (GeV)

tanβ Ratio of 2 v.e.v.’s (2 Higgs doublets; Hu & Hd)

sign(µ) Sign of Higgs mixing parameter µ (GeV)We choose µ > 0

A0 Trilinear coupling (GeV)We choose A0 = 0


Experimental ConstraintsExperimental Constraintsand Technical Issuesand Technical Issues

CLEO CLEO bb ss γγ1.9x10−4 < Br < 4.5x10−4

LEP Higgs MassLEP Higgs MassMHiggs > 114 GeV/c2

LEP/LEP/Tevatron Tevatron SUSY MassSUSY MassBoundsBounds

Relic Density BoundsRelic Density Bounds0.094 < Ωχ1

0 h2 < 0.129[WMAP, Balloon Experiments such as BoomeranG, Maxima, DASI etc., Supernovae data, Radio Galaxy measurements]

bb ss γγLarge tanβ NLO correction [Degrassi et al. , Carena et al. ]

Higgs MassHiggs MassTwo loop corrections [Haber etal. , Carena et al., Heinemeyer etal. ]

Relic DensityRelic DensityInclusion of coannihilation τ1-χ1

0

effects in relic density calculations [Ellis et al. , Arnowittet al. , Gomez et al. ]

Note:Note: We do not assume Yukawa unification or proton decay as these depend on unknown physics beyond MG.

~ ~


200

400

600

800

1000

200 400 600 800 1000m1/2[GeV]

m0[

GeV

]

A0=0, µ>0tanβ=40

b→sγ

114

GeV

117

GeV

120

GeV

m χ0>m τ

aµ<11×10-10

dark matter allowedττ11++ττ11

−− (500)(500)~~ ~~

χχ 2200 χχ1100

(800

)(8

00)

~~~~χχ 2200 χχ

1100(5

00)

(500

)~~

~~ ττ11 ++ττ11 −− (800)(800)

~~ ~~

CDM Allowed Region CDM Allowed Region mm00 vs. vs. mm1/2 1/2 ((tantanββ = 40, = 40, AA00= 0)= 0)

WMAP (blue)WMAP (blue)

Previous Estimate (red)Previous Estimate (red)Vs.Vs.

[ ] 210070 201

.hΩ. ~ <<χ

[ ]12900940 201

.hΩ. ~ <<χ

2GeV/ 250 cme~ =

We focu

s only on

the tanβ=40 ca

se,

today.τ

τ

τ1~

χ10~

χ10~

τ1~

χ10~

ττ

γ

Maximum reach for Maximum reach for mm1/21/2


200

400

600

800

1000

200 400 600 800 1000m1/2[GeV]

m0[

GeV

]

A0=0, µ>0tanβ=40

b→sγ

114

GeV

117

GeV

120

GeV

m χ0>m τ

aµ<11×10-10

dark matter allowedττ11++ττ11

−− (500)(500)~~ ~~

χχ 2200 χχ1100

(800

)(8

00)

~~~~χχ 2200 χχ

1100(5

00)

(500

)~~

~~ ττ11 ++ττ11 −− (800)(800)

~~ ~~

CDM Allowed Region CDM Allowed Region mm00 vs. vs. mm1/2 1/2 ((tantanββ = 40, = 40, AA00= 0)= 0)

360

m 1/2 m 0 M(τ1) M(χ 10) M(χ 2

0) ∆M(true) =

(GeV) (GeV) (GeV/c 2) (GeV/c 2) (GeV/c 2) M(τ1)-M(χ 10)

360 203 145.14 142.47 274.21 2.67360 204 146.29 142.47 274.17 3.82360 205 147.24 142.48 274.18 4.76360 206 148.20 142.48 274.18 5.72360 207 149.16 142.49 274.19 6.67360 208 150.12 142.50 274.21 7.62360 209 151.08 142.50 274.22 8.58360 210 152.04 142.51 274.22 9.53360 211 153.00 142.51 274.23 10.49360 212 153.95 142.52 274.25 11.43360 213 154.90 142.53 274.26 12.37360 214 155.86 142.53 274.26 13.33360 215 156.81 142.54 274.27 14.27360 216 157.76 142.54 274.28 15.22360 217 158.70 142.55 274.29 16.15360 218 159.65 142.56 274.30 17.09360 219 160.59 142.56 274.31 18.03360 220 161.55 142.57 274.33 18.98

mSUGRAA 0 = 0, µ > 0, tanβ = 40

Small ∆M

ISAJET v7.69


LHC and LCLHC and LCSmall ∆M (5-15 GeV/c2)

In order to verify the stau neutralino co-annihilation in the early universe we need to measure the mass difference between the stau and the neutralino at the colliders.

Two possible colliders: LHC (pp) and LC (e+e–)We need to discuss the signals and mass measurements at both colliders.

We focu

s only on

the m 1/2=360 ca

se,

today.

Today, we first discuss 500-GeV LC, because the SUSY masses can be measured more accurately.


SUSY Signature at SUSY Signature at 500500--GeVGeV Linear Linear Collider Collider (LC500)(LC500)

Large Large tantanββ scenario:scenario:χ1

+ > 250 GeV/c2

τ1 = Next-to-LSP

~~

τ1+τ1

− and χ20χ1

0~ ~ ~ ~

τ

z

χ10

τ1

τ

Electron beamElectron beamElectron beam

Positon beam Positon Positon beam beam

χ10

τ1

~

~

~

~

ττττ + + EEmissmiss final state:final state:Both τ-jets could be very soft for small ∆M(between τ1 and χ1

0) in τ1

+τ1− production. ~ ~

~~

σ (e+e– ee++ee––ττ) ~27,300 fb [ θ(τ) > 15o and PT(τ) > 3 GeV/c ]

Forward ee++ee–– tagging“Active mask” (very forward calorimeter)

Maximum reach for Maximum reach for mm1/21/2

RH beamsRH beams

e+

e–


Monte CarloMonte CarloEvent Generator plus Beam Event Generator plus Beam BremsstruhlungBremsstruhlung

SUSY: ISAJET v7.69e+e− χ2

0χ10 τ1τ + χ1

0 τ τ + Emiss

e+e− τ1+τ1

− τ τ + Emiss

SM : WPHACT v2.02pol(all 4 fermion final states (SM4f) and γγ process with e+/e− polarization)

e+e− νeνeττ, νµνµττ, ντντττ ; eeττ, eeqq (γγ process) Ref: E. Accomando and A. Ballestrero, Comput. Phys. Commun. 99, 270 (1997)

E. Accomando, A. Ballestrero, and E. Maina, Comput. Phys. Commun. 150, 166 (2003)

Tau Decay: TAUOLA v2.6Detector Simulation & Event Analysis:Detector Simulation & Event Analysis:

Package LCD Root v3.5FAST MC using LD Mar01 detector parameterization, Jet Finder, …

~ ~ ~~ ~

~LC500 Requirements

L = 500 fb–1

RH/LH e– beams

LC500 RequirementsLC500 RequirementsL = 500 fb–1

RH/LH e– beams

LCD RequirementsGood calorimeter + tracking systems2o or 1o active mask

LCD RequirementsLCD RequirementsGood calorimeter + tracking systems2o or 1o active mask


Optimization ofOptimization ofEvent Selection CutsEvent Selection Cuts

Beam mask: 2o(1o) - 5.8o

No EM clusters with E > 100 GeV

No electrons in θ > 25.8o

with PT > 1.5 GeV/c

τh ID (Ntrack=1, 3; q=+1)

No EM clusters in 5.8o < θ < 25.8o

with E > 2 GeV

Acoplanarity > 40o

–0.6 < cosθ(j2, Pvis) < 0.6Missing PT > 5 GeV/c| cosθjetjet | < 0.65

Njet > 2 (Ejet > 3 GeV; JADE Y>0.0025)

0.9(RH)at ~~11 −=Polττ

We focu

s only on

the RH case

, today.

1

10

100

1000

10000

0 5 10 15 20∆M (GeV)

Nev

ent @

500

fb-1

ISAJET 7.69m0 = 203 ~ 220m1/2 = 360A0 = 0tanβ = 40µ > 0

χ 10χ 2

0

τ 1τ 1

N=33N=122

Note: cos(25.8o)=0.9, cos(5.8o)=0.995

0

5

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 20

∆M (GeV)

σ B

( τh)

2 (fb)

ISAJET 7.69m 0 = 203 ~ 220m 1/2 = 360A 0 = 0tanβ = 40µ > 0χ 1

0χ 20

τ 1τ 1

2o Mask2o Mask


χχ2 2 Test ProceduresTest Procedures

∑∑

⎟⎟⎟⎟

⎠

⎞

⎜⎜⎜⎜

⎝

⎛ ⋅−=

i i

j

ji

ji FCN

2

data

data

2 MC

MCMC

σχ

Prepare “500 fb–1 experimental” data including χχ and τ1τ1 events at a specific mSUGRA point (e.g., m0 = 210).

Fit the data with the Meff [= M(j1,j2,Emiss)] templates for SM and SUSY (χχ and τ1τ1; m0 = 202 ~ 220).

Find the template that gives a minimum χ2:

~ ~~ ~

~~ ~ ~

C jMC = normalization factor (free parameters)

Nidata = number of events in i-th bin; jMC = SM, χχ or τ1τ1; Fi = shape from MC~~ ~~


χχ2 2 TestTest

Fitted with Templates(m0 = 210)




The data sample likely contains “m0 = 210” SUSY events.

“Experimental Data” (500 fb–1)m0 = 210 (∆M = 9.53 GeV)

2o Mask2o Mask

Small χ2 value

SM

τ1τ1~ ~

χ1χ2~ ~


FindingFinding χχ2 2 (minimum)(minimum)

9.5+1.0–1.0 GeV

Preliminary Result

min

imu

m Data m0 = 210

“Experimental Data” (500 fb–1)m0 = 210 (∆M = 9.53 GeV)m1/2 = 360

Compared to

Templates (high statistics samples)m0 = 203 - 220m1/2 = 360

2o Mask2o Mask


Data m0 = 205 Data m0 = 210 Data m0 = 213

All plots are preliminary.

Data m0 = 215 Data m0 = 220

2o Mask2o Mask

With 500 fb–1, it (m0 = 205) is hard to distinguish from 204 and 206.

More details(see the next slide)








2o Mask2o Mask

1o Mask?(see the next slide)

2γ events make the mass determination very difficult.

Data m0 = 205


FindingFinding χχ2 2 (minimum)(minimum)

“Experimental Data” (500 fb–1)m0 = 205 (∆M = 4.76 GeV)m1/2 = 360

Compared to

Templates (high statistics samples)m0 = 203 - 220m1/2 = 360

4.74+0.97–1.03 GeV

Preliminary Result

min

imu

m Data m0 = 205

1o Mask1o Mask


500500--GeV GeV LC PerformanceLC Performance

128311381027787122Nτ1τ1

(500 fb–1) ∆M(“500 fb–1 experiment”)

19.0+?–2.0 GeV

14.5+1.1–1.4 GeV

12.5+1.1–1.4 GeV

9.5+1.0–1.0 GeV

4.74+0.97–1.03 GeV

1o Mask2o Maskm0 (∆M)

19.0+?–2.0 GeV220 (18.98 GeV)

14.5+1.1–1.4 GeV215 (14.27 GeV)

12.5+1.4–1.4 GeV213 (12.37 GeV)

9.5+1.1–1.0 GeV210 (9.53 GeV)

Not determined205 (4.76 GeV)

Preliminary Results

~ ~

M1/2=360M1/2=360


ConclusionConclusion

[1] OnlyOnly χχ1100χχ22

00 andand ττ11ττ1 1 production are production are kinematicallykinematically allowedallowed at 500-GeV LC in cosmologically allowed mSUGRA parameter space (large tanβ).

[2] LCD with LCD with ““11oo active maskactive mask”” is importantis important to detect forward electron/ positron to suppress γγ events, especially for the small ∆M cases.

[3] RH polarizationRH polarization is crucialis crucial to reduce the SM (ννττ) events and to study the τ1τ1 production. In this channel, we have the maximum reach for m1/2 in the allowed region.

[4] MM((jj11,,jj22,,EEmissmiss) is proposed) is proposed to extract the contributions from χ1

0χ20, τ1τ1, and SM events. Our preliminary result shows that

it is possible to measure the difference between χ10 and τ1

masses.

~~ ~~ ~~~~

~~ ~~ ~~~~~~ ~~

~~ ~~


Future TasksFuture TasksPROGRESSPROGRESS

Is “1o active mask” good enough at 800-GeV LC?Can we measure small ∆M at the LHC? (w/ Aurisano, Wagner, Toback)

FUTURE TASKSFUTURE TASKSHow do we know the stau-neutralino co-annihilation is responsible for the

relic density?(1)No large higgssino component of neutralino – otherwise it will lower the relic density further.

(2)No A or H annihilation channel – it will lower the relic density.

(3)No other co-annihilation channelssuch as stop, sbottom, chargino.

All these criteria will have their unique signatures...

Small µ Check chargino …

b1~

χ10~

bb

g

χ10~

A/Hf

fχ10~ –

01

2χ~H,A MM =

Documents

mSUGRAmSUGRA Signals Signals mSUGRA Signals at ...people.physics.tamu.edu/kamon/research/talk/2004/040817...August 17, 2004 mSUGRA Signals at LHC and LC 1 R. Arnowitt,1) B. Dutta,2)