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Proton Detection at IP3 Enlarge the acceptance for diffractive protons to lower p/p ~ 10 -3. Karsten Eggert CERN / PH. Outlook: Proton Detection at Lower x -Values. Good acceptance and momentum resolution for diffractive protons needs: large dispersion D (few m) (x = D)
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Proton Detection at IP3 Enlarge the acceptance for diffractive protons to lower p/p ~ 10 -3 Karsten Eggert CERN / PH
Outlook: Proton Detection at Lower x-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?
The “Interaction Region 3” optics (x = p/p • D) Dispersion Beam size Proposed detector locations Beam size Dispersion
Beam 2 Beam 1 The “Interaction Region” 3 2 Detector Stations for Beam 2 D4 • 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.
Technical Solution: Combined Collimator + Detector momentum loss Second Beam Pipe IP 3 hit distribution in a plane transverse to Beam 2 for DPE events @ IP5 (CMS)
Particle 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 collider
Interpretation of diffractive PDF’s diffractive PDF’s • diffractive vs proton PDF’s: • larger gluon content • harder gluon structure u,d,s proton PDF’s
Proton Acceptance of a “Combined IP3 + RP220 TOTEM” Experiment Double Pomeron Exchange MPP2 = x1 x2 s DPE Mass Spectrum with Detector Acceptance x-Acceptance IR3 x IR3 IR3 x RP220 RP220 x RP220
Reconstruction phase space, IR3 @ IR3 • s(x*) = 11.8 mm • s(Q*tot) = 40 mrad • 30 mrad beam divergence • 25 mrad RMS DPE scat. angle @ IP5 ‘ ‘ ‘
Proton Momentum Resolution of a “Combined IP3 + RP220 TOTEM” Experiment Mom. loss rec. resolution s(x) / x = 10% s(x) / x = 5% s(x) / x = 1% Momentum loss
Measurement of the DPE Mass Spectrum Relative Mass Resolution Sensitivity to Resonances no accept. RP220x IR3 (e.g. 1032 s-1 cm-2 x 107s) IR3xIR3 RP220 x RP220 IR3xRP220 R = x1/x2 : characterises momentum symmetry between the 2 outgoing protons R = 1 : symmetric event.
Luminosity Measurement for all LHC Experiments After absolute stot & L measurements with TOTEM: Use low-mass DPE with both protons detected in IR3 as “standard candle”. IR3 x IR3 (0.015 mb) Identify interaction point by time difference between the 2 protons:
TOTEM • 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
The TOTEM Collaboration Penn State University, University Park Case Western Reserve Univ., Cleveland, Ohio USA INFN Sezione di Bari and Politecnico di Bari, Bari, Italy MTA KFKI RMKI, Budapest, Hungary Estonian Academy of Sciences, Tallinn, Estonia Università di Siena and Sezione INFN-Pisa, Italy Università di Genova and Sezione INFN, Genova, Italy University of Helsinki and HIP Helsinki, Finland Academy of Sciences, Praha, Czech Republic CERN, Geneva, Switzerland