Non SM Higgs Prospects @ LHC

Eilam Gross, Weizmann Institute, NSMHiggs , ichep06, Moscow1

Non SM Higgs Prospects @ LHC

Eilam Gross Weizmann institute of Science/ATLAS

•MSSM CPC Higgs Sector•Prospects for MSSM Higgs Discovery

•MSSM CPV Higgs Sector•Prospects for MSSM CPV Higgs Discovery

The flowering of the Higgs physics that is expected to bloom at the TeV scalefrom the CPNSH report: the hitchhikers guide to non-standard Higgs physicsTo be published as a CERN yellow report http://kraml.home.cern.ch/kraml/cpnsh/

Sabine Kraml

Acknowledgements:

Markus Schumacher

http://atlas.ch/index.html


MSSM

• In the MSSM model there are 5 Higgs bosons: h,H,A and H+,H-

• The relation between the SM and light SUSY Higgs couplings is given by

where is the mixing angle between the two scalar Higgs bosons and tg is the ratio between the two vacuum expectation values

cos

sinSMHbbhbb gg

sin

cosSMHcchcc gg sinSM

hVVhVV gg


The h/H Production Processes @ LHC

MAXMH

%2010~/

%2010~/

q

q

H

%5~/


Radiative Corrections

• Allow mixing ( )between scalar stop quarks (with large tg) can push the light Higgs mass upper with a maximum of ~135 GeV

• Different mixings various scenarios (benchmarks)

– MHMAX– No Mixing– Gluophobic:

Suppressed hgg coupling

– Small eff

Suppressed hbb,hcoupling

0~

tA

21~~

2~

2~

,~

~

ttttt

ttt mmmAm

Amm

R

L

diagonalization


The Gluophobic Benchmark

• The GGF process is not necessarily the dominant one. SUSY loops might reduce it. In the GLUOPHOBIC scenario the top-stop loops suppress the GGF cross section.

Min MixGluophobic


Couplings & Decay Widths

• The Higgs couple to MASS prefers downtype leptons () and b-quark• Note how h is suppressed for high tg and A is forbidden



• For large values of tg ; tg>>1tg~1/cos; cos<<1

and small values of mAmA~mh, cos2()~sin2~1Large h

• Large tgLarge A

• Large decay widths reduce the signal sensitivity with respect to the SM channels. A correction factor is applied

h



• For large values of tg ; tg>>1tg~1/cos; cos<<1

and small values of mAmA~mh, cos2()~sin2~1Large h

• Large tgLarge A, Large mALarge H

K =


Towards Experiment

• Analysis is mostly based on ATLAS fast simulation. Trigger efficiencey, Mass resolutions & Particle ID all based on Full Simulation

• Luminosity considered is – Low luminosity

30 fb-1 (1st three years LHC)

– High luminosity (+ pile up..) +270 fb-1 (another ~3-4 years)

q

q

g

gt

t

t

g

g

q

q

W

W

t

H

H

H

H

b

tg

H+

Channels taken into consideration


Towards Experiment

• When a SM analysis was applied correction factors were uses….e.g.

• LO cross sections were used (conservative!)

• A correction for widths was applied

• An increase of sensitivity was taken into account when two independent channels (e.g. H,h) overlapped.

• Dedicate searches bbh/H/A with Higgsand for Charged Higgs


Definition of Discovery

• Each channel was consideredwith its corresponding background, and an excess was considered adiscovery if the probability of the background fluctuating to the expected background+signal is less than 2.85x10-7

(poissonian, equivalent to 5 sigmas)

Channel Background

ttH, Hbb ttbb, ttqq

HZZ4l ZZ, Zbb, tt

H ,qQCD

H tt, DY, QCD

VBF HWW tt, WWqq

VBF H tt,Zqq


The Challenge

• Can we discover MSSM ?

• Which Higgs can we observe? H? h? A? H+?

• If we observe a scalar, can we tell if it’s a SM Higgs?

h?

A?H+?

H?


VBF H and h Production

• VBF is related to the MSSM Higgs coupling ghVV~sin2(), gHVV~cos2(Complementarity

• Note that the H coupling is suppressed at large mA

• The VBF is important for h close to its maximal mass (large mA) and H at its lower mass bound

q

q

H


VBF H,hWW

ATLAS preliminary30 fb-1

No mass reconstructionNeed to understandWW BG

Higgs mass & ghVV too smallBoth Production & Decay suppressed(qqqqh)xBR(hWW*) low


VBF H,h

ATLAS preliminary30 fb-1

ETmiss resolutiontag(including jet)


H,h,AGood mass resolution & photon identification compensates for the poor BR

ATLAS preliminary

300 fb-1


GGF H,hZZ4l

ATLAS Preliminary 300fb-1

• A gold plated channel for SM Higgs (due to the excellent e/ identification)

• The heavier the light h the bigger the BR(hZZ*) , • H & h are complementary, the heavier the A, the HZZ coupling

suppressedA does not couple to ZZ

• In the no mixing scenario the Higgs is lighter and the BR(hZZ*) is a killer

Higgs mass & ghVV too smallBR(hZZ*) too low


ttH,tthttbb• ttH/h is complementary to the H/hZZ

Low mAlow mhIncreasing xsc

Low tgghtt increasesIncreasing xsc


ttH

tth


ttH,tthttbb

• ttH/h is complementary to the H/hZZ

• In the minimal mixing the h mass is smaller and the coverage is full



ppbbh, bbH, bbA• Channels studies with Higgs• Channels contribute for large tg since all

couplings are enhanced wrt SM couplings by ~1/cos and H and h are complementary

• The Muonic decay mode suffers from very low BR but a clean signature

30fb-1

300fb-1

ATLASPRELIMINARY

Decreasing

Incr

ea

sin

gg

Kink @ 450 Gev due to Hhad had


Charged Higgs

• tree levelmH+

2 = mA2 + mW

2

• Rad Corrs:Charged Higgs mass can be pushed down below the W mass

• For mA<150, mH+<mtop

tH+b opens

mtop


Charged Higgs Boson

• Dominant decay mode to until the phase space for the top quark opens(at ~160 GeV)

• For mH+<mtop (mA<150) the dominant decay mode is to while for mH+>mtop (mA>150) the dominant decay mode is to tb for low tg


Production of Charged Higgs @ LHC

• Dominant production modes: For mA >150

• Dominant production modes for mA <150 via the decay of a top quark pptt, t H+ b

• Signal gbtH+ttb,tggtb


Discovery Sensitivity for Charged Higgs

• decay is decreasingasmAis increasing but scales up with increasing tg (coupling ~m tg)

ATLAS preliminary

30 fb-1

300 fb-1

Decreasing

Incr

ea

sin

gg

Mtop

Transition region requires study

ATLASPRELIMINARY

tt BG


Discovery Sensitivity for h

• For minimal mixing it seems the coverage is full


Discovery Sensitivity for h

• VBF (hVV) decouples for high tg and low mAMust use bbh, however…

• The hhas DY background and no mass reconstruction possible. h is cleaner but with a very small BR.It also decreases with decreasing tg

• Therefore for small mA the bbh with h leaves a holetowards lower tg

• There the complementary VBF H will cover


Overall Sensitivity

• In a large region only one light Higgs is observed

Lone Higgs

• SM or SUSY Higgs?

• The challenge of the LHC or the place where LHC/ILC meet


Excluded by LEP

Overall Sensitivity

• There is a full coverage in all benchmarks!

• Can the Lone Higgs region be probed for NonSM evidence?


A/H->202

0->4l + ETmiss

• Sensitivity in very specific points in the MSUGRA SUSY phase space

CMS


A Way Around the Hole

JHEP 0409 : 062 , 2004, Desch, E.G., Heinemeyer, Weiglein, Zivkoviic


A Way Around the Hole

It will take a lot of luminosity from LHC to get reasonable BRs accuracieshep-ph/0407190 Weiglein et. al.


CPV MSSM Higgs

• Can h,H and A mix?

• With complex trilinear couplings At,b

• No more well defined mA , the only remaining well defined mass

parameter is mH+

• mH1<mH2<mH3

• The CPX scenario is defined with Arg(At,b)=90o providing maximal mixing in the Higgs sector

L

LR

ijijthtt b

tQtQHgA ~

~~

,~~ *

2


Decay Modes of CPV Higgs

• In the CPC case,are forbidden

Production VBF ; ppttHi, bbHi ;

ppHi & ttH+bWb, gbH+t

A hh ,WW ,ZZ and HhZ


Decay Modes of CPV Higgs

• In the CPC case there is no coupling gAVV

Note that for mH+<150 the H1 decouples from the V Bosons


LEP results

• Loss of sensitivity around tg~3-10 due to complexity of final states(ZH26 jets… H1H2bbbb etc.)and insensitivity to very low Higgs mass


ATLAS Sensitivity to H1

30fb-1


ATLAS Sensitivity to H1

• The hole is due to:– H1VV

(decay and VBF) suppression for lighter H+ and decreasing tg

– ttH production mode is strongly suppressed for high tg

30fb-1


ATLAS Sensitivity to H2,3

• The bbH cross section is decreasing with increasing H massand decreasing tg

• There is a reduction in the decay BR in favour of bb and H2H1H1

while light H1 was not yet studied for LHC

30fb-1


ATLAS Sensitivity to H+

• Similar to CPC case (H+ is the only surviving Higgs mass eigenstate)

30fb-1


Overall Sensitivity

• Looks complete…HOWEVER 300 fb-1


Overall Sensitivity

• The hole corresponds to light Higgs mH1<70, mH+<mtop

• For each i

• Hole might be covered with additional analysis of tt with one top tbH+bWH1

and another top decaying leptonically

300 fb-1

122 ii WHHVVH gg


CPV Overall Sensitivity

300 fb-1


CPC Conclusions


CPC Conclusions

• For the CP conserving MSSM Higgs, all of the parameters space is potentially covered (30 fb-1) by the prospective discovery of at least one Higgs boson

• This coverage is seen in all benchmark scenarios and therefore reflects probably most of the MSSM phasespace

• In a Large region of the parameters space only the light SM like Higgs Boson might be observed (the “lone Higgs region”) and LHC challenge would be to tell if it is a SM Higgs Boson

• More thought and creative ideas are needed to fill the “lone Higgs region” with more observed Higgs Bosons


CPV Conclusions

• For the CP violating MSSM Higgs, although most of the parameters space is potentially covered by observing at least one Higgs Boson(300 fb-1) there is still a hole and further study is needed.

• An LHC dedicated low mass Higgs (below 70 GeV) analysis is necessary for the CPV case. An extended study of low mass Charged Higgs could improve the potential coverage

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Non SM Higgs Prospects @ LHC