1. 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

2. 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?

3. Karsten Eggert / PENN State - p. 3 Proposed detector locations Dispersion Beam size The “Interaction Region 3” optics (  x =  p/p D)

4. 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

5. 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 + Detector

6. Karsten Eggert / PENN State - p. 6 Particle production in Double Pomeron Exchange Advantage: Selection rules: J P = 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

7. 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

8. Karsten Eggert / PENN State - p. 8 Double Pomeron Exchange Proton Acceptance of a “Combined IP3 + RP220 TOTEM” Experiment DPE Mass Spectrum with Detector Acceptance M PP 2 =     s  -Acceptance IR3 x IR3 RP220 x RP220 IR3 x RP220

9. Karsten Eggert / PENN State - p. 9 Reconstruction phase space, IR3 ‘‘‘ @ IR3  (x * ) = 11.8  m  (  * tot ) = 40  rad 30  rad beam divergence 25  rad RMS DPE scat. angle @ IP5

10. Karsten Eggert / PENN State - p. 10 Momentum loss Mom. loss rec. resolution  (  ) /  = 1%   (  ) /  = 10% Proton Momentum Resolution of a “Combined IP3 + RP220 TOTEM” Experiment of a “Combined IP3 + RP220 TOTEM” Experiment

11. 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. 10 32 s -1 cm -2 x 10 7 s) no accept. Sensitivity to Resonances Measurement of the DPE Mass Spectrum

12. Karsten Eggert / PENN State - p. 12 Luminosity 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: Interaction point IP5 CMS IP8 LHCb IP1 ATLAS IP2 ALICE  t (beam 2 – beam 1) – 44  s +22  s + 44  s + 66  s IR3 x IR3 (0.015 mb)

13. 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

14. Karsten Eggert / PENN State - p. 14 The 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 USA Estonian Academy of Sciences, Tallinn, Estonia