Higgs Physics in CMS A. Nikitenko Meeting in IPM, April 2009 CERN, Building 40 CMS ATLAS

Layout IntroductionIntroduction Higgs boson searchesHiggs boson searches –In SM –In MSSM –In Extra Dimensions: Radion-Higgs sector

Introduction

SM Higgs mass constraints from the data and theory Indirect constraints from precision EW data : M H < 260 GeV at 95 %CL (2004) M H < 186 GeV with Run-I/II prelim. (2005) M H < 166 GeV (2006, ICHEP06) M H < 154 GeV (2008, Physics at LHC 08) Experiment SM theory The triviality (upper) bound and vacuum stability (lower) bound as function of the cut-off scale  “triviality” : Higgs self-coupling remains finite Direct limit from LEP M H > GeV

Tevatron SM Higgs exclusion in 2008 (Physics at LHC, 2008)

2009 Moriond

NLO M t from TeV 2005: M t =172.7+/-2.9 GeV hep-ex/ We use 175 GeV in PTDR

SM Higgs boson couplings and Br. ratios v is vev of Higgs field = 246 GeV Right bottom plot includes uncertainties from the quark masses m t, m b, m c and  s (M Z ) tree level couplings Djouadi, Kalinowski, Spira

LHC : 27 km long 100m underground General Purpose, pp, heavy ions CMS +TOTEM ATLAS Heavy ions, pp ALICE pp, B-Physics, CP Violation

Physics runs in 2010: 200 pb -1 at 10 TeV First, we should “discover” Standard Model to be prepared for Higgs discovery: QCD jets, W/Z(+jets), tt~, WW, ZZ, ….

Expected W->  at 10 TeV for 10 pb -1

W/Z+nJets one of very important background for Higgs at LHC topology Background for Higgs channel (one example) W+1j+Xgg->h->WW*->2l W+2j+X MSSM gg->bbH, H->  -> l +jet (one b-tag) W+3j+X VBF qq->qqh, h->  -> l +jet + 2 tag. jets W+4j+X VBF qq->qqh, h->WW-> l jj + 2 tag jets Z+1j+X MSSM gg->bbH, H->  ->l+jet (one b-tag) Z+2j+X VBF qq->qqh, h->  -> l +jet + 2 tag jets Z+4j+X VBF qq->qqh, h->ZZ-> ll jj + 2 tag jets Zbb,Zcc, Wbb, Wcc are as important as W/Z+nj

I present CMS Higgs physics based on CMS PTDR Vol.2 + updates for “early data”

SM Higgs boson searches Inclusive H->ZZ->4l, H-> , H->WW->2l VBF qq->qqH, H->  H->ZZ->ee 

H->ZZ (*) ->4 l - golden mode of CMS (first studies in 1995) Background: tt->WbWb->ll bb, ZZ->4l, ll bb (“Zbb”) ZZ->4l, ll bb (“Zbb”) Selections : - lepton isolation in tracker and calo - lepton impact parameter, , ee vertex - mass windows M Z(*), M H H->ZZ->ee 

H->ZZ->4l New elements of PTDR analysis: –ZZ background: NLO k factor depends on m 4l –background from side bands or from ZZ/Z; (gg->ZZ is added as 20% of LO qq->ZZ, no generator yet) Signal and background at 5 sigma discovery ee  CMS at 5  sign. CMS ee 

CMS: “early” H->ZZ->4l Exclusion goes much faster than discovery ! PTDR Vol.2: SM H->4  CMS 2009, 1 fb -1 analysis

Inclusive H->  CMS plot of the ECAL TDR time : December 1997 Went then from hybrid silicon + gas chamber tracker to all silicon tracker to all silicon tracker

PTDR design

1, uncert ~ 50%

New elements of PTDR 2006 analysis: - splitting into categories depending of R 9 =E(3x3)/E sc and  regions - splitting into categories depending of R 9 =E(3x3)/E sc and  regions - usage of LLR for discovery, systematic - usage of LLR for discovery, systematic - “optimized analysis” – NN with kinematics and  isolation as input, - “optimized analysis” – NN with kinematics and  isolation as input, s/b per event s/b per event barrel with large R 9 barrel with small R 9 endcaps with large R 9 endcaps with small R 9 1 fb -1

Discovery potential of H->  SM light h->  in MSSM inclusive search CMS PTDR 2006 ECAL TDR ECAL ECAL TDR TDR Phys TDR 2006 count. exp cut based optimized ~ Significance for SM Higgs M H =130 GeV for 30 fb -1

CMS: “early” H->  CMS, 14 TeV, 10 pb -1 CMS, 14 TeV 100 pb -1 re-scaling PTDR Exclusion goes much faster than discovery ! PTDR Vol.2: SM H-> 

Discovery of SM H->  in associated ttH and WH production at high luminosity Discovery of Wh, h->  Discovery of tth, h->  Significance of tth, h->  for 100 fb -1 L=10 34 cm -2 s -1

Accuracy of the Higgs boson mass measurement with H->ZZ->4l and H->  Stat. error only

Early discovery with H->WW->2l2...counting experiment... New elements of PTDR analysisNew elements of PTDR analysis –P T Higgs and WW bkg. as at NLO (re-weighted in PYTHIA) –include box gg->WW bkg. –NLO Wt cross section after jet veto Backgrounds from the data (and theory)Backgrounds from the data (and theory) –tt from the data; uncertainty 16% at 5 fb -1 –WW from the data; uncertainty 17% at 5 fb -1 –Wt and gg->WW bkg from theor. uncertainty 22% and 30% after cuts: - E T miss > 50 GeV - jet veto in  < <p T l max <55 GeV - p T l min > 25 GeV - 12 < m ll < 40 GeV

Discovery reach with H->WW->2l Excluded cross section times Branching Ratio at 95% C.L. CMS Phys. TDR 2006

Updated H->WW analysis 1 fb -1, 14 TeV, 2009 W+jets bkg. is addedW+jets bkg. is added Detector misalignment/miscalibrationDetector misalignment/miscalibration more conservative bkg. systematicmore conservative bkg. systematic Optimized selections for each mass pointOptimized selections for each mass point

Discovery of qqH associated production (Weak Boson Fusion) qq->qq, H-> 

(written in 2005)

Jet veto (“rapidity gap”) in VBF (WW->H) production first discussed in : Yu. Dokshitzer, V. Khoze and S. Troyan, Sov.J.Nucl. Phys. 46 (1987) 712 Yu. Dokshitzer, V. Khoze and T. Sjostrand, Phys.Lett., B274 (1992) 116 From D. Zeppenfeld talk on TeV4LHC, 2004

First, full simulation analysis of qqH, H->  ->l+jet (IC) Discovery in Standard Model discovery light h light h in MSSM in MSSM SM

CMS: “early” qqH, H->  -> l +j 1 fb -1, 14 TeV, 2008 Exclusion limit

Summary of SM Higgs boson discovery in CMS.

Prospects for SM Higgs for 200 pb -1 at 10 TeV

Searches for MSSM Higgs bosons M t = GeV M W = GeV

Unconstrained MSSM is the most “economic” version of SUSYUnconstrained MSSM is the most “economic” version of SUSY – Minimal gauge group SU(3) C xSU(2) L xU(1) Y – Minimal particle content; tree generation of spin ½ quarks and leptons [no right handed neutrino] as in SM; The two Higgs doublets leads to five Higgs particles : two CP even h, H bosons, a pseudoscalar A boson and two charged H +/- bosons –R parity conservation: Rp = (-1) 2S+3B+L –Minimal set of soft SUSY-breaking terms –Unconstrained MSSM has 124 free parameres (104 from SUSY breaking terms + 19 parameters of the SM) Constrained MSSM (or phenomenological MSSM) reduces number of free parameters to 22Constrained MSSM (or phenomenological MSSM) reduces number of free parameters to 22 – all the soft SUSY-breaking parameters are real => no new source of CP-violation in addition to the one from CKM matrix –no FCNC at tree level –the soft SUSY-breaking masses and trilinear couplings of the 1 st and 2 nd sfermion generations are the same at low energy So far most of the MSSM Higgs boson searches at LHC were performed within the framework of phenomenological MSSM (pMSSM) without assuming any particular soft SUSY- breaking scenario (mSUGRA, AMSB, GMSB,..)So far most of the MSSM Higgs boson searches at LHC were performed within the framework of phenomenological MSSM (pMSSM) without assuming any particular soft SUSY- breaking scenario (mSUGRA, AMSB, GMSB,..)

At tree level Higgs sector of MSSM is determined by two parameters: M A and tan(  ) tan(  ) = v 2 /v 1 = (v sin(  )) / (v cos(  )) tan(  ) = v 2 /v 1 = (v sin(  )) / (v cos(  )) where v 1 and v 2 are vacuum expectation values (vev) of the neutral components of two Higgs doublets. v 1 2 +v 2 2 = v 2 = 2M Z 2 /(g 2 2 +g 1 2 ) = (246 GeV) 2 Higgs masses at tree level m H,h 2 = ½[ (m A 2 +m Z 2 ) ± ((m A 2 +m Z 2 ) 2 – 4m Z 2 m A 2 (cos 2 2  )) 1/2 ] m H+ 2 = m A 2 + m W 2 m h < m Z

Constraints on MSSM Higgs from LEP searches in m h max scenario From hep-ex/ High tan  area for search at LHC with pp->bb  (  =h, H, A) with pp->bb  (  =h, H, A) and  -> ,  decays and  -> ,  decays Low tan  is not completely excluded: search for LHC with pp->A; A->Zh, , tt m t =

Light SUSY Higgs in CPX

Neutral Higgs boson couplings to fermions and gauge bosons in the MSSM at tree level normalized to the SM Higgs boson couplings g Hff =(2 1/2 G  ) 1/2 m f, g HVV = (2 1/2 G  ) 1/2 M V 2 and the couplings of two Higgs bosons with one gauge boson, normalized to g W = (2 1/2 G  ) 1/2 for g  H+W- and g Z =(2 1/2 G  ) 1/2 M Z for g  AZ  is a mixing angle between neutral components for two Higgs doublets H 1 0, H 2 0 to give the physical CP-even Higgs bosons h, H cos2  = -cos2  ((M A 2 -M Z 2 )/(M H 2 -M h 2 )) Radiative corrections introduce dependence on other parameters : , M 2, M gluino + 5 “physical” parameters: m stop1,2, m sbottom1,2,  stop or , M 2, M gluino + 5 “unphysical parameters”: m stopL, m stopR, m sbottomR, A t, A b

Cross sections for MSSM Higgs bosons production at LHC X t =6 1/2 M S (m h max scenario), M S =2TeV, m t =178 GeV, m b (m b )=4.9 GeV; NLO QCD corrections for all channels, but tt , bb  ;  R =  F =1/2(M  +2m t ) for tt  and ¼(M  +2m b ) for bb . NLO MRST set of PDF

Heavy CP-odd Higgs boson (A) branching ratios

CMS reach for MSSM neutral Higgs bosons pp->bb  (  ->h, H, A) – high tan pp->bb  (  ->h, H, A) – high tan  –  ->  –  ->  pp->A at low tan pp->A at low tan  –A->Zh Z->ll (l=e,  )Z->ll (l=e,  ) h->bbh->bb

pp->bb ,  ->  Discovery reach at low M A, “intensive coupling” and decoupling regimes Possible constraint on tan  by measuring width of A/H->  h+A h+H+A H+A

bb ,  ->2  analysis two  -jets is most challenging topology  jet2  jet1 b jet1 b jet2

H/A->2  ->ll, l+j, jj analyses m  with e/  +j and j+j modes after selections Selections include single b tagging, thus selecting gg->bbA/H production process

Z->  as benchmark for H->  mass reconstruction b(b)Z as benchmark for b(b)H Monte Carlo, NLO QCD, b-PDF

MSSM neutral Higgs bosons: TeV vs LHC CDF+D0 prospects CMS prospects for 5  discovery Phys TDR 2006 Phys TDR 2006

tan(  ) “measurement” with MSSM bbA Cross section (and width) exhibits a large sensitivity to tan(  ) and thus can add a significant observable to a global fit of the SUSY parameters R. Kinnunen, S. Lehti, F. Moortgat, A. Nikitenko, M. Spira. CMS Note 2004/027 Need to be updated From cross section of A->  From width measurement with A->  by G. Masetti, PTDR

Access to low tan  with A->Zh LEP, hep-ex/ M SUSY =1 TeV

Access to low tan  with A/H->  2 0  2 0 ->4l + E T miss BackgroundBackground –SUSY, SM: tt, ZZ, Zbb Selections:Selections: –Lepton isolation –Jet veto –E T miss, p T 4l < 80 GeV –Z veto Chosen points in mSUGRA Point C after selections

Access to low tan  with A/H->  2 0  2 0 ->4l

MSSM charged Higgs boson min at sqrt(m t /m b ) at LO m H > m t

NLO cross-section of pp->tH + as function of mass gg->tbH+ process is available in PYTHIA (S. Moretti et al. Les Houches 2003) NLO cross section is available. (T. Plehn et al., hep-ph/ ) “light” H + :gg->tt->H + bWb “heavy” H + : gg->H + tb ->H + bWb

Selections 2006: E T miss > 100 GeV E T miss > 100 GeV E T  jet > 100 GeV E T  jet > 100 GeV  polarization:  polarization: R  = p ltr /E  jet > 0.8 R  = p ltr /E  jet > 0.8 M top + b tagging M top + b tagging veto of 4 th jet veto of 4 th jet E T Higgs > 50 GeV E T Higgs > 50 GeV

CMS reach in M A -tan  with searches for charged Higgs boson Effect of systematic on discovery reach CMS Phys. TDR 2006

Summary of CMS reach in M A -tan 

discrepancy from the SM for light h M. Duhrssen et al.,hep-ph/ Can MSSM be distinguished from SM in the area of only light Higgs discovery ?

Higgs boson searches in 5D RS and Little Higgs model

Free parameters of 5D Randall-Sundrum model: m , m h,  ,  (  -h mixing)

Radion (  )->hh->  bb,  bb, bbbb search. motivation  m , GeV  ->ZZ->4l discovery no discovery for h->2   Br(h SM ->ZZ->4l) ~=  Br(  ->ZZ->4l) 30 fb -1   = 2 TeV, m h = 125 GeV X->hh discovery with ~ 30 fb -1 is a hint for radion 5D Randall-Sundrum model paramers: m , m h,  ,  We fixed : m  =300 GeV, m h =125 GeV and scan in the ( ,   ) plane - full simulation for signal:  ->hh with  bb,  bb, bbbb decay modes - fast simulation for background - MadGraph for -  jj,  cc,  bb background - CompHEP for Zbb background - Signal with corrected PYTHIA - , Br with modified HDECAY + HIGLU CMS work by D. Dominici, G. Dewhirst, A.Nikitenko, S. Gennai, L. Fano’ CMS Note 2005/007

Radion  ->hh->  bb search. selections - Two isolated photons, - Two jets of E T > 30 GeV, |  | < 2.4, at least one b-tagged jet - M , M bj, M  bj mass cuts

Radion  ->hh->  bb search. radion mass after selections at maximal signal  Br point in   -  plane at 5  discovery point

CMS reach for radion->hh->  bb in   -  plane Scan in (  ,  ) plane for m  =300 GeV/c 2, m h =125 GeV/c 2 Preliminary conclusion: inclusive h->  will be lost here, but h->  from  ->hh will be discovered

Search for pair production of doubly charged Higgs in the Little Higgs model DY prod. of  ++  -- NLO  Spira, Muhlleitner (2003)  ++ decays –  +  + –  +  + –  +  + were studied –4  –1  3 , 2  2 , 3  1  with  ->hadrons  ++  -- ->  +  +  -  - before selections after selections

 ++  -- discovery and exclusion 44 with taus in the final state. No background left !

THE END