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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


  • 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


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


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 :


Chattopadhyay et al Scenarios

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


A Scenarios

Z

W

FP


Wino LSP (mAMSB model) Scenarios

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


Chattopadhyay et al Scenarios

W

W

W

Robust results, independent of other SUSY parameters

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


Bino LSP Signal at LHC : Scenarios

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


Chattopadhyay et al Scenarios

Focus Pt SUSY

Signal at LHC


Co-annihilation region Scenarios

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


1-prong hadronic Scenariosτ 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.


Chottopadhyay et al Scenarios

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)


Higgsino LSP Signal at 3 TeV CLIC : m Scenariosχ= 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)


Polarized e Scenarios- (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


Scenariosχπ+

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


Scenariosχπ+

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.


# ev Scenarios

Sig ~ 100 (300) events with

Unpolarized (polarized) beams

103

102

The recoiling mass Mrec > 2mχ

helps to distinguish Sig from Bg

& to estimate mχ.


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)


3. Detection of HE Exptsγ 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)


γ Expts 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)


mAMSB Expts

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.


Higgsino, Wino & Bino LSP in nonminimal SUSY models Expts

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

1)

J.Ellis et al,….

2)

Chattopadhyay & Roy,….


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

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


M3 = 300, 400, 500 & 600 GeV Expts

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


Light right sleptons Expts

Even left sleptons lighter than Wino

=>Large leptonic BR of SUSY

Cascade deacy via Wino


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