1. HERA p e± 920 GeV 27.6 GeV √s = 319 GeV ep Collider
Collider experiments H1 and ZEUS
Luminosity: ~200 pb–1 in e–p
~300 pb–1 in e+p
√s = 319 GeV p e±
920 GeV
27.6 GeV

2. NC & CC cross section
electron-proton and positron-proton collisions analysed
NC: -Z0 interference at high Q2
CC: W+ (W–) exchange in e+ (e–) collisions mainly sensitive to down (up) quark density in the proton
high Q2: electro-weak unification

3. CC polarisation dependence
dependence on the longitudinal polarisation of the lepton beam
data consistent with linear dependence as expected from Standard Model
limit on mass of a right- handed W boson: M > 186 GeV (H1)

4. Multi-Leptons ZEUS 2 or 3 high PT leptons: ℓ=e, SM signal →ℓ+ℓ–
Events at high transverse momentum
DESY
H1+ZEUS combined cross-section of →ℓ+ℓ– at high PT
H1+ZEUS at ∑PT>100 GeV

5. Isolated Leptons / W production
Striking signature: ℓ=e, and  in the same event, with high PT
At large PTX>25 GeV:
ep: 23 / 14.0 ± 1.9
e-p: 6 / 10.0 ± 1.3
W cross section:
 = 1.07 ± 0.16
± 0.08 pb
SM prediction
 = 1.26 ± 0.19 pb

6. Single Top Production search in e,,hadronic W decay channel anomalous
coupling 
PLB 678, 450 (2009)
ZEUS (prel.)