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SUSY Search at Future Collider and Dark Matter Experiments. D. P. Roy Homi Bhabha Centre for Science Education Tata Institute of Fundamental Research Mumbai – 400088, India & Instituto de Fisica Corpuscular, CSIC-U. de Valencia Valencia, Spain. Outline. SUSY : Merits & Problems

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susy search at future collider and dark matter experiments

SUSY Search at Future Collider and Dark Matter Experiments

D. P. Roy

Homi Bhabha Centre for Science Education

Tata Institute of Fundamental Research

Mumbai – 400088, India

&

Instituto de Fisica Corpuscular, CSIC-U. de Valencia

Valencia, Spain

outline
Outline
  • SUSY : Merits & Problems
  • Nature of LSP : Bino, Higgsino or Wino
  • DM Constraints on Bino, Higgsino & Wino LSP Scenarios ( mSUGRA & mAMSB Models)
  • Bino LSP Signals at LHC
  • Higgsino & Wino LSP Signals at CLIC
  • Bino, Higgsino & Wino LSP Signals in DM Expts
  • Nonminimal Models for Higgsino, Wino & Bino LSP
slide3

WHY SUSY :

  • Natural Soln to the Hierarchy Problem of EWSB
  • Natural (Radiative) Mechanism for EWSB
  • Natural Candidate for the cold DM (LSP)
  • Unification of Gauge Couplings @ GUT Scale

γ

γ

h

-

e

μ

e

e

t

Split SUSY solves 2 at the cost of aggravating1.

We shall consider a more

moderate option, allowing

PROBLEMS WITH SUSY :

  • Little Hierarchy Problem 2. Flavour & CP Viol. Problem

de

mh > 114 GeV (LEP)  m > 1 TeV

slide4

Nature of the Lightest Superparticle (LSP) in the MSSM:

Exception : Mii ≈ Mjj  tan 2θij = 2Mij / (Mii – Mjj) large

“Well-tempered Neutralino Scenario”

Arkani-Hamed, Delgado & Giudice

Astrophysical Constraints  Colourless & Chargeless LSP

Direct DM Detection Expts  LSP not Sneutrino

Diagonal elements : M1, M 2, ±μ in the basis

Nondiagonal elements < MZ

Exptl Indications  M1, M 2, μ> 2MZ in mSUGRA

slide5

DM Relic Density Constraints on Bino, Higgsino & Wino LSP Scenarios

mSUGRA: SUSY Br in HS communicated to the OS via grav. Int.

 m0 , m ½ ,tanβ, A0 , sign (μ) at GUTscale ( A0 = 0 & +ve μ)

RGE ( Weak Sc masses)

Imp Weak Sc Scalar mass MHu

||

(LEP)

RGE:

Hyperbolic Br (tanβ > 5) of μ2 :

slide6

Chattopadhyay et al

m0 ~ m1/2  TeV (Bino LSP)

mh > 115 GeV  m1/2 > 400 GeV (M1>2MZ)

 also large sfermion mass

Binodoesnot carry any gauge charge

 Pair annihilate via sfermion exch

Large sfermion mass  too large Ωh2

Except for the stau co-ann. region

slide7

A

Z

W

FP

slide8

Wino LSP (mAMSB model)

SUSY braking in HS in communicated to the OS via the Super-Weyl Anomaly Cont. (Loop)

m3/2 , m0 , tan β, sign (μ)

RGE  M1 : M2 : |M3| ≈ 2.8 : 1 : 7.1 including 2-loop conts

slide9

Chattopadhyay et al

W

W

W

Robust results, independent of other SUSY parameters

(Valid in any SUSY model with Wino(Higgsino) LSP)

slide10

Bino LSP Signal at LHC :

Canonical Multijet + Missing-ET signal with possibly additional jets (leptons) from cascade decay (Valid through out the Bino LSP parameter space, including the Res.Ann Region)

Focus Point Region:

Inverted

Hierarchy

slide11

Chattopadhyay et al

Focus Pt SUSY

Signal at LHC

slide12

Co-annihilation region

Guchait & Roy

μ>0

BR ≈ 1

BR = 1

τ is soft, but Pτ≈+1

μ<0

One can use Pτto detect the

Soft τ coming from

slide13

1-prong hadronic τ decay (BR≈0.5)

With pT > 20 GeV cut for the τ-jet the τ misid. Probability

from QCD jets goes down from 6% for R > 0.3 (pTπ±> 6 GeV)

to 0.25% for R > 0.8 (pTπ± > 16 GeV), while retaining most

Of the signal.

slide14

Chottopadhyay et al

Higgsino & Wino LSP Signals at CLIC:

ν

e+

χ+

e+

W

W,B

e-

γ

χ-

e-

ν

γ

  • π± are too soft to detect at LHC without any effective tag
  • Must go to an e+e- Collider with reqd. beam energy (CLIC)

Chen, Drees, Gunion

OPAL (LEP)

χ± decay tracks :

Δm < 1 GeV  χ± and /or decay π± track with displaced vertex in MVX

Δm > 1 GeV  2 prompt π± tracks (Used by OPAL to beat ννγ background)

slide15

Higgsino LSP Signal at 3 TeV CLIC : mχ= μ ≈ 1 TeV

ν

e+

χ+

e+

W

W,B

e-

γ

χ-

e-

ν

γ

Luminosity = 103 ev/fb

# ev

106

103

(χ± decay π± tracks)

slide16

Polarized e- (80% R) & e+ (60% L) beams :

 Suppression of Bg by 0.08 & Sig by 0.8  Increase of S/B by ~ 10

# ev

104

102

slide17

 χπ+

χπ-

ν

e+

χ+

W

W,B

e-

γ

χ-

ν

γ

Prompt π± tracks in the Background from Beamstrahlung

e+

γ

π+

π-

γ

e-

Beamstrahlung Bg f ≈ 0.1:

Size of fB present for Mrec < 2 TeV

 Estimate of fB for Mrec > 2 TeV

Any Excess over this Estimate

 χ signal & χ mass

slide18

 χπ+

χπ-

ν

e+

χ+

e+

W

W

e-

γ

χ-

e-

ν

γ

  • Δm = 165 – 190 MeV for M2 ≈ 2 TeV & μ > M2
  • cτ = 3-7 cm (SLD MVX at 2.5 cm  2 cm at future LC)
  • Tracks of as 2 heavily ionising particles along with

their decay π± tracks.

Wino LSP Signal at 5 TeV CLIC : mχ= M2 ≈ 2 TeV

Both Wino Signal and Neutrino Bg couple only to e-L & e+R.

One can not suppress Bg with polarized beams.

 But one can use polarized beams to increase both Signal and Bg rates.

Polarized e-L (80%) & e+R (60%)  Probability of e-Le+R = 72% (25% Unpolarized)

 Increase of Signal and Bg rates by factors of 72/25 ≈ 3.

Bg effectively suppressed due to a robust prediction of charged and neutral wino mas diff. Δm

γ, Z

Discovery potential is primarily determined by the number of Signal events.

slide19

# ev

Sig ~ 100 (300) events with

Unpolarized (polarized) beams

103

102

The recoiling mass Mrec > 2mχ

helps to distinguish Sig from Bg

& to estimate mχ.

slide20

Bino, Higgsino & Wino LSP Signals in Dark Matter Detection Expts

1. Direct Detection (CDMS, ZEPLIN…)

χ

χ

Ge

H

Spin ind.

Best suited for Focus pt. region 

Less for co-ann & res.ann regions

χ

χ

Ge

Unsuited for (Suppressed both by Hχχ coupling and large χ mass)

p

Z

Spin dep.

p

2. Indirect Detection via HE ν from χχ annihilation in the Sun (Ice Cube,Antares)

slide21

3. Detection of HE γ Rays from Galactic Centre in

ACT (HESS,CANGAROO,MAGIC,VERITAS)

W

χ

χ

χ+

χ+

χ

χ

W

vσWW ~ 10-26 cm3/s

Cont. γ Ray Signal

(But too large π0γ from Cosmic Rays)

Wπ0sγs

γ

W

  • vσγγ~ vσγZ ~ 10-27-10-28 cm3/s
  • Discrete γ Ray Line Signal (Eγ≈mχ)

(Small but Clean)

W

W

γ(Z)

slide22

γ flux coming from an angle ψ wrt Galactic Centre

mSUGRA

∫ΔΩ=0.001srγdΩ (NFW)

Discovery limit of ACT

Chattopadhyay et al

∫ΔΩ=0.001srJ(0)dΩ≈ 1 sr (Cuspy:NFW),

103 (Spiked), 10-3 (Core)

slide23

mAMSB

Discovery limit of ACT

Chattopadhyay et al

HESS has reported TeV range γ rays from GC.

But with power law energy spec  SNR  Formidable Bg to DM Signal.

The source could be GC (Sgr A*) or the nearby SNR (Sgr A east) within its ang. res.

Better energy & angular resolution to extract DM Signal from this Bg.

slide24

Higgsino, Wino & Bino LSP in nonminimal SUSY models

LSP in SUGRA models with nonuniversal 1)scalar & 2)gaugino masses

1)

J.Ellis et al,….

2)

Chattopadhyay & Roy,….

slide25

Wino LSP in 1)Nonminimal AMSB & 2)String models

In these models:

1) Tree level SUSY breaking contributions to gaugino and scalar masses

m (tree) ~ 100 Mλ(AMSB) Giudice et al, Wells

2) String Th: Tree level SUSY breaking masses come only from Dilaton field, while they

receive only one-loop contributions from Modulii fields.

Assuming SUSY breaking by a Modulus field  Mλ& m2 at one-loop level

 M2 < M1 < M3 similar to the AMSB ( Wino LSP) & m ~ 10 Mλ

Brignole, Ibanez & Munoz ‘94

slide26

M3 = 300, 400, 500 & 600 GeV

Bino LSP in Non-universal

Gaugino Mass Model

King, Roberts & Roy 07

Bulk annihilation region of

Bino DM (yellow) allowed in

Non-universal gaugino mass

models

slide27

Light right sleptons

Even left sleptons lighter than Wino

=>Large leptonic BR of SUSY

Cascade deacy via Wino

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