16/17 August 2005 Tobias Haas: HERA II An Introduction to HERA Physics DESY Summer Student Program 16/17 August, 2005 Tobias Haas DESY, Hamburg

16/17 August 2005 Tobias Haas: HERA II Part 3: HERA II 16 August, 2004 Tobias Haas Deutsches Elektronensynchrotron

16/17 August 2005Tobias Haas: HERA II HERA II: Luminosity, e  and Polarization Polarization: Polarization: 50% reached routinely now 50% reached routinely now > 200 pb -1 /expt delivered > 200 pb -1 /expt delivered Both lepton species Both lepton species Expect ~ 700 pb -1 /expt by the end of HERA (2007) Expect ~ 700 pb -1 /expt by the end of HERA (2007) 50% Polarization (%)

16/17 August 2005Tobias Haas: HERA II HERA Lumi Upgrade : 120 pb -1 e +, 20 pb -1 e : 120 pb -1 e +, 20 pb -1 e - mainly low  mainly low  move proton quad’s from 27 to 11 m move proton quad’s from 27 to 11 m superconducting quad’s inside detectors superconducting quad’s inside detectors modest increase of beam currents modest increase of beam currents polarization polarization /7 : 1 fb /7 : 1 fb -1 I e / mA I p / mA  x / m  y / m L spec / cm 2 s -1 mA 2 L / cm 2 s -1 L int / pb < < 35 < 70 < 3 < 0.25 < 1.68 < design design 1 000

16/17 August 2005Tobias Haas: HERA II The physics from HERA-II with polarized e  beam in ep scattering does not differ (significantly) from that from HERA-I with unpolarized e  beam in ep scattering Nevertheless the longitudinally polarized e , new features the higher luminosity HERA-II the upgraded H1 & ZEUS detectors - do open up new measurement possibilities - should significantly improve the precision of all measurements made at HERA-I - may reveal surprises HERA-II versus HERA-I

16/17 August 2005Tobias Haas: HERA II H1 Upgrade polarimeters Forward tracking: Si + DC Fast Track Trigger Very Forward Proton Spectro- meter VFPS

16/17 August 2005Tobias Haas: HERA II ZEUS Upgrade Beam Pipe Magnets Straw Tube Forward Tracker Micro Vertex Detector Lumi Measurement

16/17 August 2005Tobias Haas: HERA II HERA parton density information will be quite important for the LHC data anlyses HERA parton density information will be quite important for the LHC data anlyses HERA and the LHC

16/17 August 2005Tobias Haas: HERA II e ± beam naturally transversely polarized (Sokolov-Ternov effect) P e up to ~55% Rise-time ~22min Two independent measurements by LPOL & TPOL Longitudinally polarized e ± beam Feb. 2003: a world first: Helically polarized e  colliding with a high energy proton beam with 3 pairs of spin rotators Spin rotators Polarization in HERA

16/17 August 2005Tobias Haas: HERA II Polarization in HERA Rotator UP NEGATIVE helicity Rotator DOWN POSITIVE helicity

16/17 August 2005Tobias Haas: HERA II Currently analysed Data

16/17 August 2005Tobias Haas: HERA II Charged Currents SM expectation: σ ± (P e ) = (1± P e ) σ ± (P e =0) Right-handed currents are absent

16/17 August 2005Tobias Haas: HERA II For NC: em contribution dominating at low Q 2 is independent of P e. weak NC only significant at high Q 2 Neutral Currents: Lepton species and polarization

16/17 August 2005Tobias Haas: HERA II NC Results

16/17 August 2005Tobias Haas: HERA II Neutral Currents Charged Currents The BIG picture

16/17 August 2005Tobias Haas: HERA II Charm and Beauty

16/17 August 2005Tobias Haas: HERA II What is in the proton? u, d, g ( + s + c + b)

16/17 August 2005Tobias Haas: HERA II Identifying Heavy Quarks … Method A: Method A: Identify a charmed meson in a specific decay channel Identify a charmed meson in a specific decay channel works well for c works well for c Method B: Method B: Look for leptons (e, μ) from semileptonic decays of quark Look for leptons (e, μ) from semileptonic decays of quark

16/17 August 2005Tobias Haas: HERA II Identifying heavy quarks Method C: Method C: Explore “long lifetime”, i. e. macroscopic decay length of mesons containing heavy quarks Explore “long lifetime”, i. e. macroscopic decay length of mesons containing heavy quarks c  ~ 100 – 300 μm c  ~ 100 – 300 μm Need precision tracking Need precision tracking KK  

16/17 August 2005Tobias Haas: HERA II Method C

16/17 August 2005Tobias Haas: HERA II

16/17 August 2005Tobias Haas: HERA II

16/17 August 2005Tobias Haas: HERA II What do we learn ? There is more to the proton than u and d … There is more to the proton than u and d … But QCD knows about this: But QCD knows about this: Once you add gluons … Once you add gluons … You also get charm and beauty You also get charm and beauty

16/17 August 2005Tobias Haas: HERA II Scaling in DIS Point like partons Proton Callan-Gross Spin ½ Scaling violations Gluons HERA HQ measurements Charm & Beauty

16/17 August 2005Tobias Haas: HERA II another triumph of QCD:  s (Q 2 )… QCD fit of F 2 scaling violations : QCD fit of F 2 scaling violations :  s = ± (expt+fit) ± (scale) H1  s = ± (expt+fit) ± (scale) ZEUS Jet cross sections: 1, 2, 3 jets Jet cross sections: 1, 2, 3 jets  s = ± (exp) ± (theory) running  s (E T ) in one experiment

16/17 August 2005Tobias Haas: HERA II  s at HERA precision limited by theory : NNLO non-singlet expected for 2003 NNLO singlet + gluon 2004   S HERA 1 HERA 2 experiment theory ?

16/17 August 2005Tobias Haas: HERA II HERA Anomalies

16/17 August 2005Tobias Haas: HERA II Single Isolated Leptons + E T / SM: < 1 event expected

16/17 August 2005Tobias Haas: HERA II Isolated Leptons: New Physics?

16/17 August 2005Tobias Haas: HERA II Isolated Leptons: e/μ Note: H1 Excess only in e + p data

16/17 August 2005Tobias Haas: HERA II Interpretations in terms of FCNC

16/17 August 2005Tobias Haas: HERA II Isolated τ

16/17 August 2005Tobias Haas: HERA II Isolated τ

16/17 August 2005Tobias Haas: HERA II Summary on Isolated Leptons

16/17 August 2005Tobias Haas: HERA II Multi Electron Events

16/17 August 2005Tobias Haas: HERA II Multi Electron Events

16/17 August 2005Tobias Haas: HERA II Multi Electron Events: H1

16/17 August 2005Tobias Haas: HERA II Multi Electron Events: ZEUS

16/17 August 2005Tobias Haas: HERA II Multi Electron Events: What could it be?

16/17 August 2005Tobias Haas: HERA II BSM : R p violating SUSY

16/17 August 2005Tobias Haas: HERA II Leptoquarks HERA competitive for small branching ratios: HERA 1 limits compete with LEP and Tevatron Run 1 HERA 2 limits compete with Tevatron Run 2LQ (RPV q) H1 M LQ LEPGeV/g S0LS0LS0LS0L S0RS0RS0RS0R Š0RŠ0RŠ0RŠ0R S ½ L S ½ R Š ½ L 430- S1LS1LS1LS1L V0LV0LV0LV0L V0RV0RV0RV0R V~ 0 R V 1/2 L V½RV½RV½RV½R V~ 1/2 L V1LV1LV1LV1L A.Zarnecki, EPS 2003, Aachen

16/17 August 2005Tobias Haas: HERA II BSM : R p violating SUSY SUSY-Top may be lightest squark ! Minimum Supergravity + R P violation : sensitivity to R p violating stop: HERA 1: ~ 270 GeV Tevatron Run 2: GeV HERA 2 : discovery potential !

16/17 August 2005Tobias Haas: HERA II Contact interactions new physics enters 4 fermion contact term e e q q HERA e p → e X LEP _ e + e - → q q _ FNAL pp → l l X g2M2g2M2 HERA 1 : HERA 1 : data agree with Standard Model up to highest Q 2 HERA 2 : with 500 pb -1 5  discovery if deviation data / SM > 1.5 HERA 1 : quark radius constrained to R q < m complementarity :

16/17 August 2005Tobias Haas: HERA II Contact interactions HERA, LEP, FNAL : all have similar 95% CL limits in the TeV range