Report on fitting FINAL new data: e- CC (175pb -1 : P=0.30, 71pb -1, P=-0.27, 104pb -1 )(DESY ) e- NC (169pb -1, P=+0.29, P=-0.27)(DESY ) Now add CCe+ (134pb-1: P=0.32, 78pb-1, P=-0.36, 56pb-1)(R Ciesielski) Then add NCe+ ( 113pb-1 : P=0.32, 71pb-1, P=-0.36, 42pb-1) (M Wlasenko) Improvement to PDF uncertainties Electroweak parameter fits: M W, M W / G F,M W / g Electroweak NC couplings: au ad vu vd ZEUS fits-report -High Q2 session April 2009 A.M.Cooper-Sarkar and C. Gwenlan

PDFs from the new fit compared to published ZEUS-JETS fit – central values of the PDFs do not change much….. Adding New NC and CCe- data to ZEUS-JETS fit → ZEUS-pol fit (NEW) This takes 577 data points up to 828 data points (NEW) Dataset  2/ndp ndp CC-ve poln CC+ve poln NC-ve poln NC+ve poln Quadratic  2 Remember we have shown this before with preliminary e- data- this is now final

The xu v PDF uncertainties are reduced at high-x ….. as expected since NC and CC e- cross-sections are both u dominated However some other uncertainties increase marginally- this can always happen when OFFSETing correlated errors (NEW) The d-flavour sector is less well known- NOTE the scale difference- hence we look forward to CCe+ data

PDFs from the new fit compared to ZEUS-pol fit – central values of d-valence shift a little….. Adding New CCe+ data to ZEUS-pol fit This takes 828 data points up to 893 data points Dataset  2/ndp ndp CC e-p P= CC e-p P= NC e-p P= NC e-p P= CC e+p P= CC e+p P= Quadratic  2 Note only statistical errors so far on CCe+p

The xd v PDF uncertainties are reduced at high-x ….. as expected since CC e+ cross-sections are d dominated Very marginal improvement in high-x Sea as well The d-flavour sector is improved with the addition of CCe+ data

PDFs from the new fit compared to All that came before – central values shift very little Adding New NCe+ data to ZEUS-pol +Cce+p This takes 893 data points up to 1073 data points Dataset  2/ndp ndp CC e-p P= CC e-p P= NC e-p P= NC e-p P= CC e+p P= CC e+p P= NC e+p P= NC e+p P= Quadratic  2 Note only statistical errors so far on CCe+p And only stat. +uncorreated sys. On NCe+p

The xu v PDF uncertainties are reduced at high-x ….. as expected since NC e+ cross-sections are u dominated The u-flavour sector is further improved with the addition of NCe+ data

ALL New NC/CC e- and e+ compared to ZEUS -JETS

Electroweak parameter fits Now let M W be a free parameter of the fit, together with the PDF parameters How does M W enter the fit? In the factor G F 2 M W 4 /(Q 2 +M W 2 ) ± 0.7 ± ± 0.66 ± 0.95 ZEUS-jets RTVFN including NEW CC/NC e-data ZEUS-jets RTVFN including NEW CC/NC e-data and NEW CC/NC e+ data 77.6 ± 1.4 ± ± 2.0 ± (PDF) ± 1.82(exp) (model) ZEUS HERA-I data done by this method ZEUS DESY fit to dσ/dQ2 data H1 HERA-I data done by this method Value of M W (=80.4 SM) Specifications of the fit Little correlation between EW and QCD sector of fit

Now consider fits to electroweak NC couplings as well as PDF parameters F 2 0 = Σ i A i 0 (Q 2 ) [xq i (x,Q 2 ) + xq i (x,Q 2 )] xF 3 0 = Σ i B i 0 (Q 2 ) [xq i (x,Q 2 ) - xq i (x,Q 2 )] A i 0 (Q 2 ) = e i 2 – 2 e i v i v e P Z + (v e 2 +a e 2 )(v i 2 +a i 2 ) P Z 2 B i 0 (Q 2 ) = – 2 e i a i a e P Z + 4a i a e v i v e P Z 2 The unpolarised cross-section is given by σ 0 = Y + F Y - xF 3 0 The polarised cross-section is given by σ P = Y + F 2 P + Y - xF 3 P P Z >> P Z 2 (γZ interference is dominant) v e is very small (~0.04). unpolarized xF 3  a i, polarized F 2  v i The total cross-section : σ = σ 0 + P σ P F 2 P = Σ i A i P (Q 2 ) [xq i (x,Q 2 ) + xq i (x,Q 2 )] xF 3 P = Σ i B i P (Q 2 ) [xq i (x,Q 2 ) - xq i (x,Q 2 )] A i P (Q2) = 2 e i v i a e P Z - 2 v e a e (v i 2 +a i 2 ) P Z 2 B i P (Q2) = 2 e i a i v e P Z - 2 a i v i (v e 2 +a e 2 ) P Z 2

SM formalism a i = T3 i, v i = T3 i – 2e i sin 2 Ə W Let a i and v i be free as well as PDF parameters. Perform fits with 4 NC EW parameters free NC and CCe+p data now included. Improvement is NOT due to extra statistics but due to NOT trying to compromise between two close by mimina anymore. Contours show that errors are now much less asymmetric wrt central values of the fit. auadvuvd SM value EW param 0.50±0.13± ±0.45± ±0.12± ±0.28± EW param 0.60±0.06± ±0.20± ±0.07± ±0.15±0.11

au/vu ad/vd au/ad vu/vd contours: Final HERA-II e- We look forward to NC e+ polarised data to improve this.

au/vu ad/vd au/ad vu/vd contours: Final HERA-II e- plus Prel CC and NCe+ NC e+ polarised data do improve this - it is not just statistical it is resolving a double minimum problem –hopefully the systematics will cover the SM!

Comparison with other experiments

Summary We have now repeated our preliminary work of Summer 2007 using the FINAL e- CC and NC data CCe+ improves the d-valence And MW NCe+ improves the u-valence further And the NC EW couplings For DIS re-do with just the CCe+ latest version and don’t include NC EW contour update (and probably not MW update either at this stage.

Can also fit BOTH G F and M W remember GF SM= ×10-5 Or we can fit a more general formalism: fit g and M W in g 2 / (Q 2 + M W 2 ) 2 such that g 2 =G F 2 M W 4 = for standard model G F =1.141 ± ± ×10 -5 G F =1.175 ± ± ×10 -5 M W =79.5 ± 1.3 ± 2.6 M W =77.2 ± 1.1 ± 2.0 g= ± ± g= ± ± M W =79.5 ± 1.3 ± 2.6 M W =77.2 ± 1.1 ± 2.0 This is the most general way to present our data Purple is with new NC/CC e- Red adds prel.NC/CCe+