ZEUS results for EPS-HEP combined ZEUS+H1 result

Transcription

1 results for EPS-HEP 7 + combined +H result Universität Hamburg on behalf of the (and H) Collaborations DESY seminar July 7, 7 July 7, 7

2 Results released after ICHEP 6 Hadronic final states Forward Dijets in PHP at HERAI Heavy Flavours D in DIS at HERAI Dijets in high Q DIS at HERAII Fcc from D* and D+ in DIS at HERAII Scaled momentum distribution at HERAI+II Excited charm mesons at HERAII Multi-jet cross sections in CC DIS at HERA II Charm fragmentation functions Jet substructure in NC DIS b e dijet in PHP at HERAI Measurement of s at HERA (+H) b dijet in PHP at HERAII EW and BSM Physics NC DIS with Polarised e- at HERAII Fbb at HERAII Diffraction CC with polarised e+ at HERAII Diffractive dijets in PHP and DIS at HERAI Measurement of F at high y at HERAII Dijets with a leading neutron at HERAI Di-electron production at HERAI+II Exclusive electroproduction at HERAI W and high-pt isolated leptons at HERAI+II (+H) July 7, 7 b-slope in DVCS using the LPS Elastic production at HERAI+II www-zeus.desy.de/physics/phch/conf/eps7

3 Luminosity has collected(96-7): 49 pb- of high energy data 4 pb- of low energy data 7 pb- of medium energy data. We have available HER data (polarised), LER and MER data for FL and sigma_tot measurement......it's time to concentrate on analysis... July 7, 7 3

4 First outcome for LER and MER First Events from HERA Runs at s = 5 GeV θe = 7 Ee = 5 G ev y Ee = 5 G ev Q (GeV) from HERA Runs at s = 5 GeV Q (GeV) 3 First Events θe = y Good Physics data were provided during LER and MER. July 7, 7 4

5 Results on BSM and EW physics W production and high-pt isolated leptons, H+ combined (in H talk) Multi-lepton production CC cross section in e+p collisions (6/7 data) CC in 5 e-: preliminary at ICHEP6 NC in 5/6 e-: preliminary at DIS7 July 7, 7 5

6 W production and high-pt leptons miss Events events at (e p 6 pb ) (prel.) SM MC W Prod. MC e, µ + PT events at (e p 6 pb ) (prel.) SM MC W Prod. MC 5 miss Events e, µ + PT 5 5 MT (GeV) Overflow 5 5 MT (GeV) miss + (prel.) SM MC W Prod. MC 5 events at (e p 86 pb ) e, µ + PT Events Overflow Isolated high-pt lepton in the final state, missing pt in the event. Events W l l miss e, µ + PT events at (e p 86 pb ) (prel.) SM MC W Prod. MC PXT 9 (GeV) 49 pb- of data analysed. No excess wrt standard model predictions. July 7, 7 PXT (GeV) 6

7 Multi-electron production (prel.) 478 pb SM Pair production QEDC NC ee (prel.) 478 pb SM Pair production QEDC NC eee Events Events 5 July 7, 7 5 M(GeV) 5 5 M(GeV) No excess wrt standard model predictions observed. Monica Turcato 7

8 CC in e+p collisions 4 + (prel.) e p (38. pb ) Pe σ CC (Q > GeV) (pb) Luminosity (pb ) 4 CC (prel.) e p (74. pb ) CC (prel.) e +p (38. pb ) CC (P e=) e p (6.4 pb ) CC (P e=) e+p (6.9 pb ) SM ( JETS) SM (MRST4) SM (CTEQ6D) 8 6 Parity violation is tested. 4 Polarised cross section in e+p collisions is expected to grow with the polarisation..5.5 Pe Good agreement with the SM is observed. July 7, 7 6/7 e+ data 8

9 Heavy Flavour results D and D+ production in DIS, Fcc Excited charmed mesons Beauty PHP with semi-leptonic decay into electrons Beauty PHP with semi-leptonic decay into muons July 7, 7 9

10 Charm mesons at HERAII: MVD tagging D K 4 Combinations / MeV Combinations / MeV - + ep e + D ± + X 8 Gaussmod + p 6 (prel.) 35 pb HERA II 4 N(D ±): 44 ± M(Kππ) (GeV) Gaussmod + p N(D± ): 8 ± 83 (prel.) 35 pb D S DL > 3 HERA II ep e + D + X 3 Gaussmod + p (prel.) 35 pb HERA II.8.85 JulyWithout 7, M(Kπ) (GeV) Micro Vertex Detector lifetime info M(Kππ) (GeV) ep e + D + X 8 Gaussmod + p (prel.) 35 pb HERA II N(D ±): 983 ± 55 D S DL > N(D ): 4546 ± Combinations / MeV D K Combinations / MeV 8 ep e + D± + X With MVD.5. M(Kπ) (GeV)

11 ep e + D + X 65 pb HERA I (prel.) 35 pb HERA II NLO + Fragmentation dσ/dx (nb) dσ/dq ( nb / GeV ) D production in DIS at HERAII ep e + D + X (prel.) 35 pb HERA II NLO + Fragmentation beauty contribution (RAPGAP) Q (GeV ) x Good description of the data by NLO. Charm mesons can be used to measure Fcc. July 7, 7

12 Q =.4 GeV F, FFN cc cc F, FFN.3 Q = 7 GeV cc F,FFN Fcc..4 5 X=.3(x4 ) 9 X=.8 (x4 ) X=.8 (x4 8) X=.35 (x4 7). 4 3 x X=.6 (x4 6) 4 3 x cc F, FFN Q = GeV D ± (65 pb ), D, D±s (8 pb ).4 X=. (x4 5) X=.5 (x4 4) HERA I.3 (prel.) 35 pb HERA II ( D ) F cc, FFN Prediction. Theoretical Extrapolation Uncertainty 3 X=.6 (x4 ) x X=.3 (x4 ) (prel.) D* 6 pb Improving precision wrt HERAI. Look forward to results from different D mesons combined! July 7, 7 X=.3 (x4 3) ±. 4 3 NLO 98 D* (prel.) D+ 35 pb X=.3 (x4 ) 3 4 Q (GeV )

13 Excited D mesons (HERAI) Masses and properties of D(4), D*(46),Ds(536) are measured. July 7, 7 3

14 b PHP with s/l decay into electrons (HERAI) 6 (prel.) pb 4 PYTHIA x.75 FMNR FMNR hadr The kinematic region is extended to lower pt of the electron and the jet pe T 7 (GeV) ηe 3 dσ/dxγ jet (pb/gev) e jet.5 8 (pb) dσ/de T Good agreement between data and NLO. dσ/dηe (pb) e T Beauty reconstructed from semi-leptonic decay into e. Separation between signal and background based on a likelihood function. dσ/dp (pb/gev) July 7, e jet ET 3.5 xjet γ (GeV) 4

15 b PHP with s/l decay into muons (HERAII) muons (prel.) 5 (4 pb ) LF+cc_ +bb MC LF+cc MC _ bb MC PTrel(GeV) The measurement has been obtained combining ptrel and lifetime information. Nice agreement with HERAI (similar statistics) and with NLO. July 7, 7 5

16 b summary plot Measurements done with very different methods are in agreement and well described by NLO. July 7, 7 6

17 Results on hadronic final states Jet substructure in NC DIS at HERAII Measurement of s (+H combined) July 7, 7 7

18 Jet substructure in NC DIS Perturbative QCD predicts that gluon initiated jets are broader than quark initiated jets. Difference in the jet shape observed in events with one jet (quark enriched) and two jets, looking at the second jet, close to the first (gluon enriched) July 7, 7 8

19 Measurement of s (+H combined) Idea: combine the most precise measurements from both experiments and make a simultaneous fit to both data sets, instead of combining s(mz ) values. The most precise determination of s(mz ) comes from the measurement of inclusive jet cross section in NC DIS at high-q., err.=3.6% H, err.=4.3% July 7, 7 9

20 Fit to data : inclusive jet cross section in NC DIS (5<Q< GeV) H: inclusive jet cross section in NC DIS (5<Q<5 GeV) 3 ET (GeV) 4 H 3 R ET / GeV 4 H 3 4 R July 7, ET / GeV ET / GeV 4 5 ET / GeV H ET / GeV. 5 ET / GeV 4 < Q < 7 GeV ET / GeV 7 < Q < 5 GeV 3 d σ /de T dq (pb/gev ).5 3 ET / GeV 7 < Q < 4 GeV 5 H 3 3 d σ /de T dq (pb/gev ) 5 R d σ /de T dq (pb/gev ) R 3 d σ /de T dq (pb/gev ) R NLO hadr Z...8 < Q < 7 GeV 3 H Data dσ /de T dq (pb/gev ) R 5 < Q < GeV 3 d σ /de T dq (pb/gev ) Inclusive Jet Cross Section ET / GeV 5 < Q < 5 GeV H ET / GeV 3 ET / GeV 4 5

21 Extraction of s The idea is to use NLO calculations to parametrise the dependence of an observable on s, and then to extract the s value from the measured value using the obtained parametrisation. Experimental uncertainties: energy scale, luminosity, model dependence... Theoretical uncertainties: terms beyond NLO (dominant), factorisation scale, PDFs, hadronisation corrections. July 7, 7

22 Result HERA combined (new analysis): s(mz ) =.98.9 (exp.).6 (th.) Error:.7% HERA average: s(mz ) =.86. (exp.).5 (th.) Error: 4.3% World average: s(mz ) =.89. Error:.8% The measurements are consistent with the world average. July 7, 7

23 Running of s at HERA HERA alone data show the running of s. July 7, 7 3

24 Results on diffraction Diffractive dijets in DIS Dijets with a leading neutron b-slope of DVCS using the LPS Elastic photoproduction July 7, 7 4

25 Diffractive dijets in DIS The data are described by the NLO predictions within theoretical uncertainties. Data are better described by the H6 FitB and MRW 6 dpfds. The data are able to discriminate between NLO predictions based on different dpdfs. July 7, 7 5

26 Events Dijets with a leading neutron (prel.) 4 pb ep ex Q > GeV γp jjx Q < GeV xbp DIS inclusive xl distribution reweighted in xbp agrees with both the direct and resolved parts of dijet PHP July 7, 7 No clear evidence for absorption 6

27 DVCS with the LPS at HERAI The kinematic region has been extended to lower Q values The b slope is measured directly using events tagged by the LPS Inclusive sample July 7, 7 (34 events have a proton tagged in the LPS) 7

28 Elastic production p p Cross section has been measured in two W bins, using 4 pb-of data. It is consistent with previous measurements, and more precise. July 7, 7 8

29 Summary Many analyses are combining HERAI and HERAII data, others are on the way to. Interesting results are coming out of high energy data, also using the polarisation information. The LER and MER running have provided good quality data. Time to focus on analysis! The amount of available data is pretty high :-) July 7, 7 9

30 Backup slides July 7, 7 3

31 D+ production in DIS at HERAII ep e + D± + X 65 pb HERA I (prel.) 35 pb HERA II NLO + Fragmentation beauty contribution (RAPGAP) dσ/dx (nb) dσ/dq ( nb / GeV ) 3 ep e + D± + X (prel.) 35 pb HERA II NLO + Fragmentation beauty contribution (RAPGAP) 3 4 Q (GeV ) x Data are well described by NLO QCD predictions. Precision is better than for HERAI July 7, 7 3

32 Diffractive dijets in PHP Reasonable agreement between data and NLO QCD predictions. No evidence for a suppression of the cross section in the resolved-enriched sample (x obs<.75) July 7, 7 3