T.Hebbeker

First Results from LHC

Thomas Hebbeker RWTH Aachen

T.Hebbeker

• Accelerator and detectors• Rediscovery

of the

Standard Model particles

• First measurements

2009

T.Hebbeker

• Accelerator and detectors• Rediscovery

of the

Standard Model particles

• First measurements

2009

T.Hebbeker

CERN Control C

entre

Nov. 2009

2009: 0.9 TeV c.m. p p

2.36 TeV

2010: 7 TeV c.m. p p 30 / pb per exp (?)

574 TeV c.m. Pb Pb

201X:

14 TeV

c.m. p p 105

/ pb

/year

CERN Control Center

T.Hebbeker

LHC luminosity

here CMS,similar for the other experiments

7 TeV

c.m.

scm //10 227

scm //108 231⋅>

increase

of instant. lumiby

> 4 orders

of magnitude!

ICHEP conference

2010

explosive growth !

2 x 248 bunches

T.Hebbeker

LHC

Tevatron

Tevatron

and LHC

7 TeVsome

/pb

2 TeVsome

/fb

LHC starts

to overtake

Tevatron

!

How is this possible with today‘s luminosity ?

pppp

T.Hebbeker

Tevatron

and LHC

25)2,()7,(

≈TeVttTeVtt

σσ

How can LHC compete with Tevatron already with today‘s luminosity ?

300)2,'()7,'(

≈TeVWTeVW

σσ

TeVWm 1)'( =Ja

mes S

tirling

T.Hebbeker

CMS

ALICE

ATLAS

LHC-B

T.HebbekerALICE = A Large Ion Collider ExperimentL3solenoid

dipole

T.HebbekerATLAS = A Toroidal LHC ApparatuS

T.HebbekerCMS = Compact Muon Solenoidsuperconducting coil

iron yoke

silicon tracker

elm. calorimeter

hadron calorimeter

muon chambers

T.HebbekerCMS = Compact Muon Solenoid

GeVEEE

GeVEEE

GeVp

pp

hadhad

had

elmelm

elm

T

T

T

/%100

/%3

005.0101 4

≈Δ

≈Δ

⊕⋅⋅≈Δ −

T.HebbekerLHCb = Large Hadron Collider Beauty Experiment

forward

direction

T.Hebbeker

• Accelerator and detectors• Rediscovery

of the

Standard Model particles

• First measurements

2009

T.HebbekerTypical event

HCALECAL

0.9 TeV

T.Hebbeker

few cm

T.Hebbeker

gWZγ

τμe

tbcsdu

ν

jets

missing

energy

hadrons

decay

mode lifetime invariant mass

Rediscovery

of the

Standard Model particles

T.Hebbeker

Photons

7 TeV

c.m.

GeVET 70≈

elm. energy

T.Hebbeker

μμ→Z

7 TeV

c.m.

T.Hebbeker

eeW ν→7 TeV

c.m.

Missing ET

elm. energy

elm. energy

= neutrino

!

T.Hebbekergluon

2.36 TeV

c.m.

at least one

jet

is

a

gluon

jet

T.Hebbeker

Tau

7 TeV

c.m.

+ neutrinos

!

2nd vert.

νννμττ

hadronsZ

+→+→

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Quarks - Jets

7 TeV

c.m.

elm. energy

had. energy

T.HebbekerMesons, e.g. π0

γγπ →0

light quarks

(u,d) !

detector

resolution

!

T.HebbekerBaryons, e.g. Xi = Ξ

ππp→

strange

quarks!

detector

resolution

!

T.HebbekerDimuon event (J/ψ

candidate)

elm

!

charm

quarks!

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Dimuon resonances

bottom

quarks!

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fully

reconstructed

!

bottom

quarks!

T.HebbekerLHCb B D

−+++

+−

→

→

KKD

DB

s

ss

π

νμ μ

tertiary

vertex

T.HebbekerTop

e

μ

νμν bebbWbWtt →→

MET

b

b

7 TeV

c.m.

T.Hebbeker

• Accelerator and detectors• Rediscovery

of the

Standard Model particles

• First measurements

2009

T.Hebbeker

Hadron production

First LHC physics paper

Good agreement

SPS ( pp) –

LHC (pp) at same

energy

non singlediffractivenormalization

inelasticnormalization

data: Nov 23paper: Dec

1

284 events

-

T.HebbekerHadron production

inelastic

fitStrong

increase

with

energy

0=η

GeVpT 5.0>

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Multi hadron production

7 TeV

c.m.

dedicated trigger !

> 100 tracks

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Particle correlations in multi hadron events

newin pp

T.Hebbeker

Inclusive Strange Particle Production

Example: Ξ-

Yield

increases

stronglywith

energy

not predicted by currentMonte Carlo `tunes`

T.HebbekerInclusive b-hadron production

First measurements

at 7 TeV

-

agreement

with

expectations

62 << η

T.HebbekerB oscillations

Rediscovery

!

char

ge

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Inclusive jet production5 o

rder

sof m

agnit

udes

Agreement with

QCD prediction

over

several

orders

of magnitude

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Dijet production and resonance search

jetsgqq 2* →→

compositeness:

excited quarks excluded up to a mass of

1.53TeV (95%)

world record !

compositeness scale*)(qm=Λ

(Tevatron limit: 870 GeV)

T.HebbekerW production

Note: In pp

more

W+

than

W-

Perfect

agreementwith

SM

l = e, μ

W mass

confirmed

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Z production

Note: in pp

less

Z bosons

than

in pp-

l = e, μ

Nice

agreementwith

SM

T.HebbekerTop production

Agreement with

SM cross section

coming

soon

jetjet

T.HebbekerSearch for W´

W‘

excluded

up to m=465 GeV (Tevatron

limit: 1 TeV)

T.HebbekerSummary