Prospects of Charged Higgs Boson Discovery @ Colliders

D. P. Roy

Homi Bhabha Centre for Science Education

Tata Institute of Fundamental Research

Mumbai, India

• Charged Higgs Boson in the MSSM

• H Lighter than top(t): t bH+

• H Heavier than top : gbtH- (NLO Cont.)

• H± beyond the MSSM : NMSSM & CPVMSSM

• SUSY QCD Correction to H± signature

Outline

0,, WhtbH

8 States - 3 Goldstone = 5 Physical St : h0, H0, A0& H±

H± carries unambiguous hallmark of MSSM Higgs sectorAll the MSSM Higgs masses & couplings => MA & tan β

01

02

,..,

02

2

,..,1

01 /tan:

ctb

MSSM

222

01

02

012 sinImcosIm,sincos

WAH MMM

AH

RLc

RbLt

Wmscm

btmbtmH

M

gL

tancot

tancot

2

RLc

RbLt

Wmscm

btmbtmH

M

gL

tancot

tancot

2

mt > MH± => large tbH+ BR at tan β 1 & tan β mt/mb

H± decay: tan β < 1 & tan β > 1

(MH± < 140 GeV) H± cs H± τν=> Deficit in t bW blν

(MH± > 140 GeV) H± t*bWbb => t bH+ bbbW=> b tag excessMoretti & Stirling; Djouadi, Kalinowski & Zerwas; Ma, Roy & Wudka

LL QCD Corr => mq mq(MH±) => mt =170, mb = 3, mc =1 GeV

Pert. Lim. of H±tb coupling => tan β > 1/3 & tan β < 3mt/mb 170

MH= 140 GeV

tan β ~ 8 problematicUsing τ Pol can helpto enhance Hτν Sigover W Bg

Production of Heavy H± ( MH > mt ) at LHC

LO

NLO QCD Correction => K 1.5 (Zhu; Plehn et al.)

(a)g

b

t

g

H¯

+

g

b

t

H¯

t

t

g

b

t

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g => 0.8 (0.6)

(b) - overlapping cont. from LO => -0.3 (0)

for μF = μR = MH + mt , ( μF = (MH + mt)/5)

t

H¯

b

g

g

tb

Main BRs of H± (MH>200)

H± tb dominant atall tanβLarge QCD BgSignals with 3 & 4 b-tags

H± Wh(A) main subdominant at small tanβ ~ 3 (BR 5%)Marginal in MSSM(NMSSM & CPV-MSSM)

H± τν main subdominantat large tanβ > 10 (BR~20%)Most promising Signal

Heavy H± (MH>200GeV) Signal at LHC in hadronic τ decay channel

g

g

t Wbt

Wqqbt 'g

b

t

Wqqbt '

H

jet

h

Sig has much harder pTτ-jet > 100 GeV (Enhanced by τ pol effect).

Azimuthal angle between τ-jet and missing-pT is peaked in backwarddirection for signal ( forward direction for background).

Transverse mass of τ-jet and missing-pT —> MH for Sig (MW for Bg)

τ-Polarization: 11

,

P

LR

P

RR WH

%)5.7(%),26(%),12( 1 a => 90% of 1-pr.hadronic decay

0,2/1

2/1

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R

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V = ρ,a1

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RH

H τ (Pτ =+1) gives hard τ-jet from π,ρL, a1L

W τ (Pτ = -1) gives hard τ-jet from ρT , a1T

Can be distinguishedfrom X = pπ± / pτ-jet

Raychaudhuri & Roy

Hardness of π± reqd for τ-id=> X > 0.3 (low-X peaks of ρL , a1Linaccessible)

X > 0.8 cut will retain the high-X ρL & π conts ( Pτ = + Signal),while effectively suppressing the ρT ,a1T conts ( Pτ = – bg ).

It will also suppress the fake τ bg from QCD jets effectively.

Guchait, Kinnunen & Royhep-ph/0608324

Hardness of π± reqd for τ-id => X > 0.3

X > 0.8 cut retains most ofthe remaining Signal, whileeffectively suppressing the Bg.

PYTHIA+TAUOLA+ CMSJET

p

pR3

3-prong τ-jet without π0

R3 > 0.8 or < 0.4 retains most of the Signal, whilesuppressing the Bg.

mT > 200 GeV cuteffectively suppresses the Bg withoutaffecting the Signal.Provides estimate ofH± mass.

H± discovery limit at LHC with luminosity of 30 fb -1 (solid)and 100 fb -1 (dashed lines).

Detection of H± tb Signal at LHC with 3 b-tags : Moretti & Roy

g

b

t

H¯

t qqbbl

tbttHgbSig

. 3

333 ,, bmistaggedtgtggtbtgbbbttggBG

pT (b3) > 80 GeV

BG large, but5σ Sig possibleat very large (small)tan β

H± tb Signal at LHC with 4 b-tags: Miller, Moretti, Roy& Stirling

t

H¯tb3

b4

g

g

tb

434: bbttbtHggSigqqbbl

43*: bbttgttggBg

qqbbl

Eb3> 120 GeV

Mbb> 120 GeV

cos θbb < 0.75

pT (b4 )>20 GeV

Better Sig/Bg at the cost of a smaller Sig size compared to the 3 b-tags

Assamagan, Coadou& Deandrea

..~&..~ HgHqcan fill up intermediate tanβ region for some favorableSUSY parametersDatta, Djouadi, Guchait& Mambrini

Viability of H± tb channel is not supported by the full simulation study:Lowette, D’Hondt &Vanlaer

Extensions of MSSM (NMSSM & CPV-MSSM)

Low Tanβ ( < 5 ) region: A not observable at LEPMSSM: Mh > 110 GeV => MA > 160 GeV => MH±> 180 GeV

NMSSM: Allows MA1 < 60 GeV with a large doublet component & MH± = 140 - 160 GeV => H± A1W Drees,Guchait & Roy

CPV-MSSM: hA mixing => light H1 with large A comp, MH1< 60 GeV & MH±= 130-150 GeV => H± H1W±

t bH± bH1W bbbW Ghosh, Godbole & Roy

t bH± bH1W bbbW

SUSY QCD Correction : Non-decoupling Hall et al., Carena et al., Coarasa et al.,Bartl et al.

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mmnessNaturalm

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Estimate of Δb at Snowmass points & slopes in mSUGRA, GMSB &AMSB => Δb 20% for tanβ 30 ( ΔKSM~ 20%) Plehn et al.