Karsten Eggert / PENN State - p. 1

Karsten Eggert

CERN / PH

Proton Detection at IP3

Enlarge the acceptance for diffractive protons to

lower p/p ~ 10 -3

Karsten Eggert / PENN State - p. 2

Outlook: Proton Detection at Lower -Values

Good acceptance and momentum resolution for diffractive protons needs:

large dispersion D (few m) (x = D)

small beam width (< 1 mm)

Where in the LHC are these requirements best fulfilled?

Karsten Eggert / PENN State - p. 3

Proposed detector locations

Dis

pers

ion

Dis

pers

ion

Beam

siz

eBe

am s

ize

The “Interaction Region The “Interaction Region 3” optics (3” optics (x = x = p/p • D)p/p • D)

Karsten Eggert / PENN State - p. 4

D4

2

The “Interaction Region” 3

• Advantage for machine protection: collimator downstream of detectors absorbs possible showers.• Diffractive proton rate of ~ 3 MHz hits Q6 magnet (~5MHz quench limit)• Warm region!

• Detect diffractive protons from all interaction points.

Detector Stations

for Beam 2

Beam 2

Beam 1

Karsten Eggert / PENN State - p. 5

Second Beam Pipe

IP 3 hit distribution in a plane transverse to Beam 2 for DPE events @ IP5 (CMS)

momentum loss

Technical Solution: Combined Collimator + DetectorTechnical Solution: Combined Collimator + Detector

Karsten Eggert / PENN State - p. 6

Particle production in Double Pomeron ExchangeParticle production in Double Pomeron Exchange

Advantage: Selection rules: JP = 0+, 2+, 4+; C = +1 for exclusive particle production

Determination of quantum numbers

Production of gluonic states, c , b , Higgs, supersymmetric Higgs,…..

• Low mass states need high* (e.g. 90 m)

• Higgs and high mass states need high luminosity

• Enlarge the mass acceptance down to ~ 100 GeV

Additional Si-detectors at IP3

Use the LHC as a gluon-gluon colliderUse the LHC as a gluon-gluon collider

Karsten Eggert / PENN State - p. 7

Interpretation of diffractive PDF’s

diffractive vs proton PDF’s:

• larger gluon content

• harder gluon structure

proton PDF’s

diffractive PDF’s

u,d,s

Karsten Eggert / PENN State - p. 8

Double Pomeron Exchange

Proton Acceptance of a “Combined IP3 + RP220 TOTEM” Experiment

DPE Mass Spectrum with Detector Acceptance

MPP2 = s

-Acceptance

IR3 x IR3

RP220 x RP220

IR3 x RP220

Karsten Eggert / PENN State - p. 9

Reconstruction phase space, IR3Reconstruction phase space, IR3

‘ ‘ ‘

@ IR3

(x*) = 11.8 m(*

tot) = 40 rad • 30 rad beam divergence• 25 rad RMS DPE scat. angle

@ IP5

Karsten Eggert / PENN State - p. 10Momentum loss

Mom

. los

s re

c. re

solu

tion

() /

= 1%

() /

= 10%

Proton Proton Momentum ResolutionMomentum Resolution

of a “Combined IP3 + RP220 TOTEM” Experimentof a “Combined IP3 + RP220 TOTEM” Experiment

Karsten Eggert / PENN State - p. 11

R = 1/2 : characterises momentum symmetry between the 2 outgoing protons

R = 1 : symmetric event.

IR3xIR3

RP220x IR3

IR3xRP220

RP220 x

RP220

Relative Mass Resolution

(e.g. 1032 s-1 cm-2 x 107s)

no a

ccep

t.

Sensitivity to Resonances

Measurement of the DPE Mass SpectrumMeasurement of the DPE Mass Spectrum

Karsten Eggert / PENN State - p. 12

Luminosity Measurement for all LHC ExperimentsLuminosity Measurement for all LHC Experiments

After absolute tot & L measurements with TOTEM:

Use low-mass DPE with both protons detected in IR3 as “standard candle”.

Identify interaction point by time difference between the 2 protons:

InteractionInteractionpointpoint

IP5IP5CMSCMS

IP8IP8LHCbLHCb

IP1IP1ATLASATLAS

IP2IP2ALICEALICE

t t (beam 2 – beam (beam 2 – beam 1)1)

– – 44 44 s s +22 +22 ss + 44 + 44 ss + 66 + 66 ss

IR3 x IR3

(0.015 mb)

Karsten Eggert / PENN State - p. 13

will be ready for data-taking at the LHC start

will run under all beam conditions

will need special high * runs

will pursue a common physics program with CMS

Karsten Eggert / PENN State - p. 14

The TOTEM CollaborationThe TOTEM Collaboration

MTA KFKI RMKI, Budapest, Hungary

University of Helsinki and HIP Helsinki, Finland

CERN, Geneva, Switzerland

Academy of Sciences, Praha, Czech Republic

INFN Sezione di Bari and Politecnico di Bari, Bari, Italy

Università di Siena and Sezione INFN-Pisa, Italy

Università di Genova and Sezione INFN, Genova, Italy

Penn State University, University Park

Case Western Reserve Univ., Cleveland, Ohio

USAEstonian Academy ofSciences, Tallinn, Estonia