recent studies on sparticles and mssm higgses at cms massimiliano chiorboli university and infn...

Recent studies on sparticles and Recent studies on sparticles and MSSM Higgses at CMSMSSM Higgses at CMS

Recent studies on sparticles and Recent studies on sparticles and MSSM Higgses at CMSMSSM Higgses at CMS

Massimiliano Chiorboli

University and INFN Catania

17-23 Feb 2002Lake Louise Winter Institute Massimiliano Chiorboli

OutlineOutlineOutlineOutline

Minimal Supersymmetric Standard Model: theoretical aspects

MSSM Higgses

A,H l+l-

l--jet 2 -jets

A,H

4l + X

H+

sbottom and gluino reconstruction


MSSMMSSMMSSMMSSM

Higgs sector:

2 CP-even: h,H

1 CP-odd: A

2 charged: H

Fermions:Fermions: quarks, leptons s = ½

Gauge Bosons:Gauge Bosons: W±, Z0, ,gluons s = 1

HiggsesHiggses s = 0

Sfermions:Sfermions: squarks, sleptons s = 0

Gauginos:Gauginos: Wino, Zino, fotino, gluino s = 1/2

Higgsinos s = 1/2

mA tan

1HττbHb cosβg,g

high tan gg Hbb H

H~

,~ ,Z~

,W~ 4,1 ,χ~ 2,1 ,χ~ 0 ji jimixing


The CMS detectorThe CMS detectorThe CMS detectorThe CMS detector


A,H A,H A,H A,H

jets- HA,

jet-HA,

HA,

2

• Lepton ID from ECAL or -chambers

• l tagging by IP of the lepton (tracker)

• -jet:

• 1 (3) tracks, pT>40 GeV within R(jet,track)<0.03

• no track, pT>1 GeV within 0.03 < R < 0.4

no stop mixing

MSUSY=1 TeV, =-200 GeV, M2=200 GeV, Xt=0


A,H A,H ll llA,H A,H ll ll2 leptons, pt

e, > 20 GeV, | e,|< 2.5

b-tagging of the associated jet

-tagging through IP of the 2 hard l suppress Wl and Z ll bkg

no-tagging


A,H A,H l + l + jetjetA,H A,H l + l + jetjet

One isolated lepton, pT>15 GeV, ||<2.4

-jet, ET>40 GeV, ||<2.4

60° < (l – t-jet) < 175°

Etmiss > 20 GeV

mT(l – Etmiss) < 30 GeV

b-tagging of the associated jet

mA=140 GeV mA=300 GeV

tan =8 tan =15

tan =30

tan =40


A,H A,H 2 2 jetsjetsA,H A,H 2 2 jetsjets

• 2 -jets, ET>60 GeV, ||<2.5

• qi(jet1) * qi(jet2) < 0 in R<0.03

• Etmiss > 40 GeV

• (-jet1 – -jet2) < 175°

• No Etmiss cut

• 1 b-jet, ET>30 GeV


A,H A,H

4l 4l + X+ XA,H A,H

4l 4l + X+ X

low tan Small H0,A0 – couplingSM bkg: ZZ, ZW, Zbb, Zcc, Wtb, tt

SUSY bkg: direct sparticles production

0250

1

12060

~

~~

t

g,q

21

AGeV, M

TeV M GeV, -500

GeV M GeV, M

• 4 isolated leptons, pT>10 GeV, ||<2.4

• Z-veto

• 20 GeV < Etmiss <130 GeV

2 jets, ET < 50 GeV


Charged HiggsCharged HiggsCharged HiggsCharged HiggsIn some cases (, bb) the neutral Higgs bosons may be hard to distinguish from the Standard Model Higgs at LHC

H tb, higher BR, but large irreducible bkg

H , lower BR, but more clean environment

Observation of charged Higgs physics beyond SM


HH HH

• 1 -jet, ET>100 GeV, ||<2.5

• Etmiss > 100 GeV

• W and top mass reconstruction

• b-tagging

• (-jet, Etmiss) > 60°

jets W Wtb,,tt bkg gg tbH, H


55 contours contours55 contours contours


Sparticles searches at CMSSparticles searches at CMSSparticles searches at CMSSparticles searches at CMS

Until now, excesses over the SM…

New studies: sparticle reconstruction…

mSUGRA

0

0

A

)( sign

m

m

21

tan


Sparticle reconstructionSparticle reconstructionSparticle reconstructionSparticle reconstruction

bb~

g~ pp

b~02

01

~ ~

p

p

g~

b~

b

b

01

~

02

~ ~

2 isolated leptons, pT>15 GeV, ||<2.4

2 b-jets, pT>20 GeV, ||<2

• Etmiss > 50 GeV

tt, Z+jet, W+jet, ZZ, WW, ZW

10 fb-1 first 6 months at LHC

0A

)( sign

10β tan

100m

250m

0

0

21


First step: First step: 2200 l l++ll- - 11

00First step: First step: 2200 l l++ll- - 11

00

02

~ 01

~

~p

p

g~

b~

b

b

01

~

02

~ ~

p

M

M1p

01

02

~

~

GeV 85.32 M

)M)(MM(MM

2

χ

222

χmax01

02

~

~~~~

GeV 1.64 86.00 Mmax

Fit result:

)μM(μ )eM(e -

)μM(e -)μM(e - )μM(μ )eM(e --


Sbottom reconstructionSbottom reconstructionSbottom reconstructionSbottom reconstruction

Etmiss > 150 GeVEt

miss > 50 GeV

p

p

g~

b~

b

b

01

~

02

~ ~Assuming M(1

0) known!


Sbottom mass peakSbottom mass peakSbottom mass peakSbottom mass peak

47.5

GeV 6.6509.5b)~M( 02

GeV 7.549)b~

M(

GeV 5.522)b~

M(

R

L

Result of fit:

Generated masses:


Gluino reconstructionGluino reconstructionGluino reconstructionGluino reconstruction

p

p

g~

b~

b

b

01

~

02

~ ~

Etmiss > 150 GeV

GeV 643.3)gM( ~Generated mass:

66.6σ

GeV 9.2611.2bb)χM( 02

~

Result of fit:


Combinatorial suppressionCombinatorial suppressionCombinatorial suppressionCombinatorial suppression

b)b~

( angle φ sbottom

gluino4. 0 cos

8. 0 cos

4. 0 cos

8. 0 cos


estimationestimation estimationestimation

doesn’t depend on M(10) !)b

~M(-)g~M(

GeV 30)~M( 01

)bM(-)gM(~~ )bM(-)gM(~~

30.8σ

GeV 5.887.0b)χM(bb)χM( 02

02

~~

Result of fit:


ConclusionsConclusionsConclusionsConclusions

CMS will be able to discover MSSM Higgses within the first 2 years of run in wide mA-tan regions (A,H

Far from bounds (high tan), mass peaks recontruction possible

Decays into sparticles can cover low tan regions

Sparticle reconstruction possible within the first 6 months of running for some mSUGRA parameter regions

Gluino and sbottom mass peak, dependent on M(10)

M(gluino) – M(sbottom), independent of M(10)


HH tb tbHH tb tb

jtt jj,tt ,bbtt bkg


h h h h excellent ECAL resolution large prompt

bkg

mH = 120 GeV

100 fb-1

SM MSSM

recent studies on sparticles and mssm higgses at cms massimiliano chiorboli university and infn...

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h slide

gev slide

gev tan

gev e t

gev p p b b

h fermions

gev tt

track1 gev