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EW at HERA. a nd “RELATED” NEW PHYSICS. HERA: a QCD and EW machine Results on: EW constraints Isolated Leptons Single TOP. Luca Stanco – INFN Padova on behalf of ZEUS and H1 collaborations. HERA: a collider e-p. ZEUS. H1. 1993-2007. HERA-II.
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EWatHERA and “RELATED” NEW PHYSICS • HERA: a QCD and EW • machine • Results on: • EW constraints • Isolated Leptons • Single TOP Luca Stanco – INFN Padova on behalf of ZEUS and H1 collaborations EW and NP at HERA, Photon 2009
HERA: a collider e-p ZEUS H1 1993-2007 HERA-II Last Fill the 30th June 2007 HERA-I 0.5 fb-1 per exp.: e+p, e-p, LowEnergyRange, MER EW and NP at HERA, Photon 2009
HERA: the QCD machine Gluons and QCD dynamics For Q2 ≈ M2Z,M2W study also EW interactions: CC double diff. cross-section Beam Polarization QPM Structure Functions EW and NP at HERA, Photon 2009
HERA-II feature: Polarization EW and NP at HERA, Photon 2009
Q2 ∼ 1/l : the scale of the interaction corresponds to the spatial resolution at which the proton structure is probed EW and NP at HERA, Photon 2009
ElectroWeak unification: status-of-the-art Neutral e-p (ZEUS publ., H1 prel.) Current e+p (ZEUS prel., H1 prel.) Charged e-p (ZEUS publ., H1 prel.) Current e+p (ZEUS prel., H1 prel.) g-exchange M2Z and M2W dominate exhanges ( corrected for the Polarization effects ) EW and NP at HERA, Photon 2009
NC and Structure Functions: Parity Violation test EW and NP at HERA, Photon 2009
Weak Interaction check with Polarization (CC) V-A chiral structure (ZEUS preliminary 2007) WR>208 GeV EW and NP at HERA, Photon 2009
Weak Interaction check with Polarization (NC) Parity Violation size, Asymmetry proportional to vector coupling demonstrated down to 10-18 m EW and NP at HERA, Photon 2009
DGLAP fits for QCD-EW: PDFs’ and uv-quarks couplings • Simultaneous test of the EW and Strong sectors of SM • Best determination of u-coupling to Z • - Competitive with Tevatron and LEP results EW and NP at HERA, Photon 2009
Isolated high-pT leptons: status-of-the-art Final analysis from H1 and ZEUS on Electron and Muon leptons H1 looked also at the Tau leptons: challenging, large background (combined in progress) nice Jacobian peaks, however at hight pT… EW and NP at HERA, Photon 2009
Gerard Brandt at DIS09 H1: EW and NP at HERA, Photon 2009
Anomalous SingleTOP production at HERA Final results from H1 (HERAII: 474 pb-1), HERAI+II in DESY-09-50 ZEUS preliminary:277 pb-1 (HERAII), combined with HERAI (120 pb-1) Neglet c and Z couplings. Sensitive to u (valence) and anomalous g exchange Search for signal in muon, electron, hadron channels Intrinsic background from SM production of W (lepton decay) EW and NP at HERA, Photon 2009
No excess limits, H1: s < 0.25 pb, ktug < 0.18, ZEUS: s < 0.13, ktug < 0.13 (slight excess) Stefano Antonelli at DIS09 EW and NP at HERA, Photon 2009
Conclusions • H1 and ZEUS exploit most of HERA DATA • for EW studies • Unique HERA results done and undergoing • Many EW checks,Universality, Chiral Structure, • Parity Violation • Single W production, measured, • intriguing signal left at hight pT • Anomalous Single TOP production, • SM checked (Colliders complementarity) BIG thanks to HERA !! EW and NP at HERA, Photon 2009
Backup Slides EW and NP at HERA, Photon 2009
Chiral Structure of CC, by ZEUS DESY-08-177 Total cross-section vs Electron Polarization provides striking evidence EW and NP at HERA, Photon 2009
Isolated Lepton yield EW and NP at HERA, Photon 2009
SingleTOP production at HERA in the SM EW and NP at HERA, Photon 2009
SingleTOP results from H1 Slight excess in the muon and electron channels EW and NP at HERA, Photon 2009
SingleTOP results from ZEUS Muon channel EW and NP at HERA, Photon 2009