Summary LHC Physics-2006

Tariq Aziz

TIFR, Mumbai

Workshop on LHC Physics-2006 4-8 September, 2006

Many interesting talks : My sincere apologies to all

LHC : 27 km long100m underground7TeVX7TeV PP

General Purpose,pp, heavy ions

General Purpose,pp, heavy ions

CMS+TOTEM

ATLAS

Heavy ions, pp

ALICE

pp, B-Physics,CP Violation

The Monster is getting ready to Unleash it’s Power

A. Gurtu, A. Nikitenko, S. Banerjee

Motivation

• High Energy Physics community will like to observe signatures of last corner stone of Standard Model and Physics Beyond it

• Large Hadron Collider is built to collide protons at a centre of mass energy of 14 TeV and at a luminosity of 1034 cm-2 s-1

Bunch Crossing 4x107 Hz

Proton collision 109 Hz

Parton collision

New particle production 102 Hz

• Two general purpose detectors, ATLAS and CMS, are designed to be sensitive to all new physics channels

• Compact Muon Solenoid (CMS) is a 12.5kton detector, 21.6m long and of 14.6m in diameter

S. Banerjee

LHC Schedule (from June CMS Week)

Experiments told to have beam pipe in place, connected and ready by 1st Sept instead of 1st July 2007. CMS 'Ready to Close' is then be set to 31 August 2007.

Schedule for the 2007 pilot run is: Date 1= 1 Sept (i-e 2 month delay wrt to official LHC schedule):

Expts ready to close with beam pipe installed. Date 2= Date 1 + 6 weeks (?) = ~ 15 Oct: Expts closed ready for

collisions.

Following June Scientific Policy Committee meeting it is decided that in the run of 2007 the LHC will start commissioning with collisions at injection energy (450 GeV). Discussions are going on how much higher in energy the machine can go before the winter shutdown.

A. Gurtu

Field 4 Tesla

Inner Bore 5.9 m

Length 12.9 m

Number of turns 2168

Current 19.5 kAmp

Stored energy 2.7 GJ

Summary of Magnet tests as of 28 August 2006: 4 Tesla field reached !

CMS choice: Superconducting Solenoid using a high purity Aluminium stabilized NbTi conductor and cooled by an external cryogenic sysytem

A. Gurtu, S. Banerjee

CMS: The Most Powerful Magnet Ever Built

A. Gurtu

Progress in Cosmic Challenge till 28 August

A Slice of Detecor is readyRecord 15 M Events at 3.8 and 4T

Should give a couple of thousand good tracks

We have proven that CMS is a functioning detector

A. Gurtu

Tracker is at the heart of the CMS detector: An all silicon solution for the tracking

Designed to reconstruct charged tracks with excellent momentum resolution and efficiency better than 98% for |η| < 2.5

Designed to identify tracks coming from detached vertices

Largest Silicon Tracker Ever Built

154000 Strip modules with 9.6 million readout channels

1440 Pixel modules with 66 million readout channels S. Banerjee

New Analysis Developments from CMS

http://cmsdoc.cern.ch/cms/cpt/tdr/

CERN/LHCC 2006-001 CERN/LHCC 2006-021

Published submitted to LHCC

A. Nikitenko

Physics runs 2008-2009Physics runs 2008-2009

First , we should First , we should “discover” Standard Model“discover” Standard Model

• Top with 300 pb-1 – simple selection : Missing ET, 1 lepton, ≥4 jets , NO b-tag (!), cut on

hadronic W mass

Atlas FullSim Preliminary

Top pair events in 300 pb-1

Mreco

• Drell-Yan (W, Z) production of lepton pairs– best known cross section at LHC NNLO : scale uncert. ~ 1%

Dixon, Anastasiou, Melnikov, Petriello

– Constrain PDFs, eg. from W+/W-

– Luminosity monitor

Jet energy scale from Wjet jet, commission b-tagging

““Discovery” of the Standard Discovery” of the Standard ModelModel

Understand the LeptonsUnderstand the Jets

A. Nikitenko

Discover the ‘Discovered’ to know the Potential for Undiscovered

First Data

• 1 fb-1(100 pb-1)= 6 months(few days) at L=1032cm-2sec-1

with 50% data taking efficiency a few 1/fb per experiment at the

end of 2008

W,Z events will be used for calibrationTop events also will be used to for JES,.. M. Guchait

PDF: W/Z process

The experimental uncertainty small to

Distinguish the PDF sets.

PDF errors are sensitive to e rapidity

Distributions

ATLAS studies shows it is possible to distinguish different PDF if Exp. Uncertainty ~3-5%

CTEQ61 MRST02 ZEUS02

CTEQ61 MRST02 ZEUS02

e- rapidity e+ rapidity

GeneratedGenerated

y

d(W

e

)/dy

y

d(W

e

)/dy

Reconstructed Reconstructed

W±→e±ν rapidity distributions

eWud

eWdu

M. Guchait

H->ZZH->ZZ(*)(*)->4->4ll - golden mode of CMS - golden mode of CMS

Background: tt, ZZ, Background: tt, ZZ, llllbb (“Zbb”)bb (“Zbb”)

Selections :Selections :- lepton isolation in tracker and calolepton isolation in tracker and calo- lepton impact parameter, lepton impact parameter, , ee vertex , ee vertex - mass windows Mmass windows MZ(*)Z(*), M, MHH

H->ZZ->ee

A. Nikitenko

HiggZWlogy at LHC, H->ZZ, WW

H->ZZ->4lH->ZZ->4l

• New elements of analysis:

– ZZ background: NLO k factor depends on m4l

– 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 discoverySignal and background at 5 sigma discovery

ee

CMSCMSat 5at 5 sign. sign.

CMSCMSat 5at 5 sign. sign.

ee

A. Nikitenko

Early discovery with H->WW->2l2Early discovery with H->WW->2l2 ...counting experiment... ...counting experiment... Discovery reach with H->WW->2l Discovery reach with H->WW->2l

CMS Physics TDR 2006after cuts: - ET

miss > 50 GeV - jet veto in < 2.4 - 30 <pT

l max<55 GeV - pT l min > 25 GeV - 12 < mll < 40 GeV

A. Nikitenko

Exploit τ-Polarization at LHC

11

,

P

LR

P

RR WH

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

0,2/1

2/1

V

R

L

H

V = ρ,a1

2/111

2/1

LV

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

τ-Polarization:

D.P.Roy

First, full simulation analysis of qqH, H->First, full simulation analysis of qqH, H->->l+jet ->l+jet

Discovery in Standard ModelDiscovery in Standard Model

discoverydiscovery light hlight h in MSSM in MSSM

SMSM

A. Nikitenko

Taus as Discovery tools at LHC

D.P.Roy

CMS Potential for SM Higgs Boson Discovery CMS Potential for SM Higgs Boson Discovery

A. Nikitenko

CMS reach for MSSM neutral Higgs bosonsCMS reach for MSSM neutral Higgs bosons

• pp->bbpp->bb ( (->h, H, A) – high tan->h, H, A) – high tan->->->->

• pp->A at low tanpp->A at low tan

– A->Zh , Z->ll (l=e, A->Zh , Z->ll (l=e, ) and ) and h->bbh->bb

A.Nikitenko

pp->bbpp->bb, , ->->Discovery reach at low MDiscovery reach at low MAA, “intensive, “intensive

coupling” and decoupling regimescoupling” and decoupling regimesPossible constraint on tanPossible constraint on tan by by measuring width of A/H->measuring width of A/H->

H/A->2H/A->2 analysis 2006 analysis 2006

m with e/+j and j+j modes after selections

Selections include single b tagging, thusSelections include single b tagging, thusselecting gg->bbA/H production processselecting gg->bbA/H production process A. Nikitenko

Z->Z-> as benchmark for as benchmark for H->H-> mass reconstruction mass reconstruction

CMS, 2006CMS, 2006

Z->Z->->->+jet in CMS, 2006: +jet in CMS, 2006: S ~ 1000 ev, B: tt ~ 60 ev., W+j ~ 40ev. , bb ~ 60 ev. S ~ 1000 ev, B: tt ~ 60 ev., W+j ~ 40ev. , bb ~ 60 ev. for 30 fbfor 30 fb-1-1

bbZ as benchmark for bbH bbZ as benchmark for bbH kinematicskinematics

Z+2 b-tagged jetsat CMS, 2006

MSSM neutral Higgs bosons at LHCMSSM neutral Higgs bosons at LHC

CMS prospects for discovery CMS prospects for discovery Phys TDR 2006Phys TDR 2006

A. Nikitenko

Selections 2006:Selections 2006:

EETTmissmiss > 100 GeV > 100 GeV

EETT jetjet > 100 GeV > 100 GeV

polarization:polarization: RR = p = p ltrltr/E/E jet jet > 0.8 > 0.8

MMtoptop + b tagging + b tagging

veto of 4veto of 4thth jet jet EETT

HiggsHiggs > 50 GeV > 50 GeV

A. Nikitenko, D.P.Roy

If SUSY is seen, Can we reconstruct the masses?

K. Mazumdar

CMS reach at LHC CMS reach at LHC

• The latest simulation studies show: The latest simulation studies show: – SM inclusive h->2SM inclusive h->2 could be discovered with < 10fb could be discovered with < 10fb-1-1, ,

associated with tt and W (tth, Wh): >= 100 fbassociated with tt and W (tth, Wh): >= 100 fb-1-1 at high lumi at high lumi– almost no change in the discovery potential with H->ZZ->4l almost no change in the discovery potential with H->ZZ->4l

and H->WW->2l. First study of Higgs CP properties with and H->WW->2l. First study of Higgs CP properties with H->ZZ->4lH->ZZ->4l– tth, h->bb is lost as discovery channel even with 60 fbtth, h->bb is lost as discovery channel even with 60 fb -1-1

– qqh, h->qqh, h-> “survived” after full simulation ! The biggest “survived” after full simulation ! The biggest discovery reach in Mdiscovery reach in MAA-tan-tan

– MSSM HMSSM H++ : gap in M : gap in MAA-tan-tan at M at MH+H+ ~ m ~ mtt is closed is closed– MSSM HMSSM H++->-> and H/A-> and H/A-> : discovery reach is a bit reduced : discovery reach is a bit reduced

with full simulation, reconstruction and systematicswith full simulation, reconstruction and systematics– MSSM MSSM (h,H,A)->(h,H,A)-> : possible to constrain tan : possible to constrain tan with width with width

measurementmeasurement– first studies on Higgs in 5D RS and little Higgs models first studies on Higgs in 5D RS and little Higgs models

Tracking for Better JetsOlga Kodolova

Understanding different contributions to Jet is a delicate balancing act

LHC will tell Or will it?

And the winner is…

A. Raychaudhuri, B. Mukhopadhyaya, A. Datta …

Scalar mass not protected by any symmetry

SM and BSM

Study of WW scattering can give information on Electroweak SymmetryBreaking sector and discriminate between different models

S. Rindani

Knowledge of Higgs Production Cross-Section Pretty Good

Too many terms

NNNLO on the way

Need Reliable estimate of Higgs Cross-Section at LHC

V. Ravindran

Models that were successful in describing SPS datafail to describe data at RHIC - too much suppression -

Heavy Ions, QGP …..

RV Gavai RK Choudhuri

Implementing regeneration: much better agreement with the data

RKC

R. Gavai

R. Gavai

Heavy-ion physics at LHC

LHCRHIC

Vogt, hep-ph/0205330

J/

Medium modification at high pT Copious production of high pT particles Large jet cross-section

Different melting for membersof Y family depending on bindingenergy Larger cross-section for J/and Y families

Correlations, scattering in medium jets directly identifiable

O. Kodolova

At LHC a new regime of heavy ion physics will be reached where hard particle production can dominate over soft events, while the initial gluon densities are much higher than at RHIC, implying stronger partonic energy loss observable in new channels.

CMS is an excellent device for the study of quark-gluon plasma by hard probes: - Quarkonia and heavy quarks - Jets, ''jet quenching'' in various physics channels

CMS will also study global event characteristics: - Centrality, Multiplicity - Correlation and Energy Flow reaching very low pT

CMS is preparing to take advantage of its capabilities - Excellent rapidity and azimuthal coverage, high resolution

- Large acceptance, nearly hermetic fine granularity hadronic and - Large acceptance, nearly hermetic fine granularity hadronic and electromagnetic calorimetry electromagnetic calorimetry - Excellent muon and tracking systems - Excellent muon and tracking systems - New High Level Trigger algorithms specific for A+A- New High Level Trigger algorithms specific for A+A

- Zero Degree Calorimeter, CASTOR and TOTEM will be important - Zero Degree Calorimeter, CASTOR and TOTEM will be important additions extending to forward physics additions extending to forward physics

What CMS can do in Heavy Ion Physics at LHC

O. Kodolova

Post LHC Scenarios in High Energy Physics

If Liberals are right: Surge of Hep Activity

Larger Hep Collaborations

If Conservatives are right: We see SM objects

Light Higgs Confirmed

If none are right: More exotic, but beyond reach

Last Hep Community

Days of Judgment are getting closer !

Backup Slides

V. Ravindran

Cross sections for MSSM Higgs bosons production at LHCCross sections for MSSM Higgs bosons production at LHC

Xt=61/2MS (mhmax scenario), MS=2TeV, mt=178 GeV, mb(mb)=4.9 GeV;

NLO QCD corrections for all channels, but tt, bb; R=F=1/2(M+2mt) fortt and ¼(M+2mb) for bb. NLO MRST set of PDF

Muon System

• Identification: At least 16λ material present up to |η|=2.4• Trigger: Combination of precise and fast detectors for trigger on single

or multi muon events with pT from a few to 100 GeV• Momentum Resolution: Standalone 8-15% at 10 GeV to 20-40% at 1

TeV. Global 1-1.5% at 10 GeV to 6-17% at 1 TeV• Charge Assignment: Correct to 99% confidence up to 7 TeV

CMS Detector

A. Gurtu, S. Banerjee, A. Nikitenko