17 April. 2005,APS meeting, Tampa,FloridaS. Bhattacharya 1 Satyaki Bhattacharya Beyond Standard Model Higgs Search at LHC

17 April. 2005,APS meeting, Tampa,Florida S. Bhattacharya 1

Satyaki

Bhattacharya

Beyond Standard Beyond Standard Model Higgs Model Higgs

Search at LHCSearch at LHC


* numbers are for barrel

data taking starts 2007

Startup Luminosity 1033 cm-2/s

that is: 10 fb-1 per year

Silicon Tracker15 ( )%T

TT

p p TeVp

2.7% 0.150.5% E

E EE

PbWO4 ECAL

sampling brass HCAL 120

5%E

E E

solenoid4Tesla field

1.0 1.5%@100T

T

pglobal GeV

p

MUON Chambers


Higgs in Higgs in MSSM MSSM


MSSM Higgs sector MSSM Higgs sector

01

1

H

H

02

2

H

H

Two Higgs doublets

8 real Higgs fields( 4 complex fields)

3 fields are

gauged away

01

0

0 02

cos sin

sin cos

H

h

0 01 2

0 , ,, , A H H

All masses, and mixing angle are determined by two independent parameters, generally taken as

tan – ratio of vacuum expectation values of the two doubletsMA – mass of pseudoscalar Higgs A

pseudoscalar Higgs

charged Higgs

heavy Higgs

light Higgs


MSSM Higgs Production MSSM Higgs Production

h production x-sections similar to SM higgs in decoupling regionggh largest

ggH/A most important at low tan

at high tangg/qqHbb dominant for H/A

for H± tttH-bis most important


CMS Detector: schematic X-sectional view

HCAL

ECAL

TRACKER

h h Two clean electromagnetic clusters(For unconverted photons)

Backgrounds: gg,qq,qgq @low luminosityjet-jet 105 events/sjet+photon 102 events/s2 photon 1 event/12.5sHiggs 1 event/25sh2photon 1 event/10,000s

@low luminosityjet-jet 105 events/sjet+photon 102 events/s2 photon 1 event/12.5sHiggs 1 event/25sh2photon 1 event/10,000s

two photon background

gamma+jet background


hh mass resolutionmass resolution

=646MeVe

ven

ts/5

0M

eV

mfor 130 GeV Higgs

CMS full detector simulation. Ref: CMS Note 2003/033


A/HA/H jets + X jets + X

backgrounds: Z/2multijets faking tt and W+jet with W

reduce background by requiring: high pt narrow jet, isolation, b-tag, impact parameter

NLO x-section used

Signal:Production: ggbbH/A and ggH/ADecay: H/A+

MA 500GeV: .Br=0.188pbMA 200GeV: .Br=9.53pb

~15% mass resolution

Higgs signal over total backgroundPythia simulation

Ref: CMS Note 2003/006

Mass can be reonstructed assuming ||


h discovery @ 30fbh discovery @ 30fb-1-1

Decay branching ratios and searches for h are like SM Higgs

Ref: CMS Note 2003/033

5 discovery with 30 fb-1 possible in this region using h decay


A/H and HA/H and H± ± Discovery RegionsDiscovery Regions

At large tanAt large tan A/H coupling to A/H coupling to down type fermion is strong and down type fermion is strong and H production with bH production with bb b and H and H decay to decay to become important become important

For charged Higgs associated For charged Higgs associated production with top is dominantproduction with top is dominant


SummarySummary

• At LHC Higgs mass range between LEP bounds and ~1 TeV can be probed

• Atleast one MSSM Higgs will be found in entire MA-tan plane

• All MSSM Higgs should be visible in large region of the parameter space

• 5 discovery possible with 30 fb-1 in large region of the parameter space

• Few hundred MeV mass resolution for light Higgs from h

cmsdoc.cern.ch/~anikiten/cms-higgs/Higgs Working Group Summary, Les Houches 2004,hep-ph0406152

for more information


The EndThe End


Higgs Production in MSSM(details)Higgs Production in MSSM(details)

• H/A production– ggH/A, gg/qqbbH/A– g(AVV)=0 no VBF– At large tanβ

• VBF suppressed for H• g(A/Hbb) enhanced

~90% bbH/A for tanβ>10 and MA>300 GeV

– H SM-like near lower mass limit ( high tanβ, small

MA)VBF significant

• h production– h SM-like for MA>mh

max

• H± productionFor MH±<Mt : tttH±b

For MH±>Mt:

– ggtbH±,H+H-,W±H±

– gbtH±

– qqH±

Higgs couplings with up(u) down(d) fermions and vector bosons (v)


MSSM Higgs Production (updated from M. Spira)MSSM Higgs Production (updated from M. Spira)


MSSM Higgs Production (ii)MSSM Higgs Production (ii)


channels considered for a SUSY Higgschannels considered for a SUSY Higgs• H/h , bb

– H->bb in WH,ttH– h-> in Wh, tth->l

• H/hZZ*/ZZ4l • h/H/A(e/jETeET, jjET

– Including qqH,ttH,WH

• H+from tt• H+, H+tb for MH+

>Mt

• AZh with hbb• A• H/A ij• H±+

~ ~ ~ ~ ~

~

~

~


A/HA/H jets + X (detailed efficiency) jets + X (detailed efficiency)


H/A H/A

• ppbbH/A + X with H/A

2soft(ET< 50GeV) b jets

– Use b-tag against Z/* background

– Use central jet veto against tt

Mass resolution 1%, |mH-mA| ~ 2 GeVH/A peaks superimposed

(mass difference can be upto ~ 5.5 GeV)


CMS Trigger RatesCMS Trigger Rates

CMS total level1 rate is 16 kHz at startupTotal High Level Trigger (HLT) is 100 Hz.


Extra Slides on Extra Slides on Standard Model Standard Model

HiggsHiggs


Higgs production at LHCHiggs production at LHCggH

High gluon flux – dominant although loop process

Vector Boson Fusion (VBF)

10% at MH=100GeV

Comparable to gg->H at MH=1 TeV

ttH, bbH,HW,HZ


Decays and Search StrategyDecays and Search StrategyMH < ~140 GeV

Hbb dominantggHbb : background too large

ttHttbb possible

H–small BR but very clean

MH < ~500 GeV 120-200 GeV

HWW*/WWll(serious t,Wtb background)

200-500 GeVHZZ4l gives highest sensitivity

between 200-500 GeV

MH > ~500 GeVH large, use channels with large BR,

HZZ/WW

VBF x-sec large and can be used

sear

chch

anne

ls


Discovery reach of CMSDiscovery reach of CMS

• CMS can probe the entire “allowed” mass range

• 5 discovery possible in few months in many channels

Total

HHZZl+l-l+l-HWWll

Documents

17 April. 2005,APS meeting, Tampa,FloridaS. Bhattacharya 1 Satyaki Bhattacharya Beyond Standard Model Higgs Search at LHC