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Karsten Eggert CERN / PH
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Transcript of Karsten Eggert CERN / PH
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