Electron-Proton-Collider Projects HERA eRHIC March 29,2007 Electron-Proton Projects

(Wo)manpower Overview-status 3/07 H1 Scientists Permanent Postdocs PhD Students V. Chekelian J. Bracinik B. Antunovic G. Grindhammer B. Olivier A. Dossanov C. Kiesling A. Raspereza R. Kogler A. Litpaj A. Nikiforov ZEUS I. Abt D. Kollar P. Devgun A. Caldwell B. Reisert I. Jassal W. Schmidke March 29,2007 Electron-Proton Projects

Electron-Proton Projects HERA HERA II e-P: ca. 290 pb-1 delivered e+P: ca. 275 pb-1 delivered HERA II Run ended March 22, 2007 Low energy running til July 2, 2007 March 29,2007 Electron-Proton Projects

Electron-Proton Projects Jet Trigger The jet trigger is an upgrade to the H1 first level trigger (large scale effort of MPI electronics department + physicists) Jet finding at the first level Reduced thresholds since use local sums Operational since fall 2006 March 29,2007 Electron-Proton Projects

Electron-Proton Projects Jet Trigger e Jet Trigger Level 1: 1 ms CC analysis - improved efficiency for small angles ! Level 3: 150 ms rate reduction x100 for low pT b-quarks and J/Psi Low Proton Energy run: Low energy electron trigger for y high NC 1 subtrigger LAr Trigger OR of 3 subtriggers March 29,2007 Electron-Proton Projects

Electron-Proton Projects HERA II Results Neutral Currents at high Q2. Polarization allows extraction of au,vu,ad,vd March 29,2007 Electron-Proton Projects

Electron-Proton Projects HERA II Results Charged Currents Purely weak scattering - parity violation See no Right-handed currents March 29,2007 Electron-Proton Projects

Electron-Proton Projects HERA II The analysis of the HERA II data is producing results. Long list of expected analyses: high Q2 and high x structure functions, polarization dependence flavor dependent structure functions (F2c,b , u/d ratio, …) EW parameters heavy flavor production, fragmentation jet production, jet properties, S, … exotica diffraction, exclusive processes, small-x physics Focus on the low energy run currently in progress March 29,2007 Electron-Proton Projects

Electron-Proton Projects Proton Structure Q2 dependence in agreement with the expectations of perturbative QCD (famous Dokshitzer, Gribov, Lipatov, Altarelli, Parisi evolution equations). DGLAP March 29,2007 Electron-Proton Projects

Electron-Proton Projects Proton Structure (small selection of data) QCD based fits can follow the data accurately, yield parton densities. DGLAP March 29,2007 Electron-Proton Projects

Electron-Proton Projects Proton Structure BUT: many free parameters (18-30) (DGLAP only knows how parton densities evolve in Q2) form of parametrization fixed by hand (not given by theory) Fits don’t agree at small-x ! In particular, large uncertainty in gluons parametrizations should not be extended beyond measurement range in x (divergence at fixed small-x larger at low Q2, smaller at high Q2) March 29,2007 Electron-Proton Projects

Electron-Proton Projects FL Need better data to test whether our parton densities are reasonable. The structure function FL will provide an important test. negligible at small Q2 y2/Y+ r 1 F2 F2-FL Need two beam energies to measure FL Ecm1 Ecm2 Directly sensitive to xg at small-x March 29,2007 Electron-Proton Projects

Electron-Proton Projects Low Energy Run The HERA low energy has started and is planned to continue until 2 July, 2007 at 10:00AM. Expect 10 pb-1 of data. March 29,2007 Electron-Proton Projects

Electron-Proton Projects FL H1 The FL measurement at HERA will serve primarily as a check of the gluon distributions extracted using the DGLAP fits CTEQ5D R=0.25 MRST2002(LO) 0.30 MRST2004(NLO) 0.18 MRST2004(NNLO) 0.18 ZEUS March 29,2007 Electron-Proton Projects

Electron-Proton Projects Beyond HERA SLAC-MIT,… Rutherford HERA Understand small-x physics and hadronic structure is unfinished business. Ultimate goal is wavefunction of hadrons. 6-D structure - position & momentum distributions of partons, how spin is built up nature of diffraction & high energy limit of interactions March 29,2007 Electron-Proton Projects

Electron-Proton Projects Beyond HERA Ee=3-20 GeV Pe=80% Ep=50-250 GeV Pp=70% L=530 pb-1/week EA=50-100 GeV/A PA=0% L=580 pb-1/week/A eRHIC NSAC long range planning under way - priorities set this spring Other ideas: forward physics at LHC, LHeC March 29,2007 Electron-Proton Projects

Electron-Proton Projects Beyond HERA We have outlined a detector design for eRHIC based on our experience with the HERA physics - full acceptance detector. hep-ex/0407053 March 29,2007 Electron-Proton Projects

Electron-Proton Projects Conclusions HERA high luminosity running is over - run was successful, first results are coming out. There are proposals under serious discussion for a future DIS program. Low energy run has just started, and is expected to continue til the end of HERA (July 2, 2007)  FL. March 29,2007 Electron-Proton Projects