1 / 35

News from

News from. Delia Hasch. 62 th Physics Research Committee, DESY-Zeuthen Oct 23/24 2006. data taking 2006. PRC62. Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006. e + data.

cyndi
Download Presentation

News from

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. News from Delia Hasch 62th Physics Research Committee, DESY-Zeuthen Oct 23/24 2006

  2. data taking 2006 PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 e+ data e-data • data taking: • efficiency >98% •  spectrometer in • excellent shape

  3. data taking 2006 PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 e+ data e-data • data taking: • efficiency >98% •  spectrometer in • excellent shape • polarisation: • PBl=+1 ~ 0.3-0.4 • PBl=-1 ~ 0.2-0.3  

  4. status of detectors • new target cell installed: •  thicker cell walls •  improved cooling • silicon detector: •  modules repaired •  RF shielding installed • … more details @closed session PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 • spectrometer in excellent shape • target cell + recoil silicon:all problems fixed !

  5. status of detectors since September: recoil fully commissioned PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 • spectrometer in excellent shape • target cell + recoil silicon:all problems fixed ! • since July taking data with all recoil components: silicon ADC spectra before repair after repair SciFi track reconstruction

  6. DS PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 HERMES @SPIN2006 • final results on g1 for the proton and deuteron • flavour decomposition of Dq     talks by L.DeNardo, H.Jackson • new result on DG talk by P. Liebing • news on transversity & friends talks by M.Diefenthaler, M.Contalbrigo • hunting DL: DVCS, excl. r0 talks by W.D.Nowak, H.Guler, E. Kinney

  7. final HERMES result on g1 PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 world data [hep-ex/0609039]

  8. x MS MS a0= DS = 0.35 ± 0.03(stat) ± 0.05(sys+evol) a0= DS(theory) (exp) (evol) = 0.330 ± 0.011 ± 0.025 ± 0.028 spin crises PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 the integral of g1 [Q2>1 GeV2 data only] assume saturation ofG1d : COMPASS: [hep-ex/0609038] …EMC (1988) : DS = 0.12±0.17

  9. AAC GRSV BB LSS • need more direct probes PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 news on DG [hep-ph/0603213]

  10. PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 direct measurement of DG • golden channel: charm production • @HERMES: hadron production at high PT ALL eN  hX (e’ not in acceptance) PythiaMC: Dg/g = -1 Dg/g = 0 Dg/g = +1

  11. PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 direct measurement of DG • golden channel: charm production • @HERMES: hadron production at high PT : direct, resolved, soft processes signal processes: PGF QCD 22(g)

  12. PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 direct measurement of DG • golden channel: charm production • @HERMES: hadron production at high PT method I: method II: …with two different functional forms

  13. Dg/g +0.127 x (sys-model) -0.105 PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 direct measurement of DG • golden channel: charm production • @HERMES: hadron production at high PT <m2>=1.35 GeV2 <xg>= 0.22

  14. PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 quark structure of the nucleon

  15. PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 quark structure of the nucleon unpolarised quarks and nucleons longitudinally polarised quarks and nucleons transversely polarised quarks and nucleons h1(x): helicity flip chiral-odd  needs a chiral odd partner: SIDIS: COLLINS-FF  azimuthal asymmetry AUT

  16. naïve T-odd DF • requires orbital angular momentum PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 CollinsandSivers moments distinctive signature Collins moment Sivers moment Collins and Sivers moments extracted by fitting the asymmetry with:

  17. PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 & K +/- Collins moments p+/- • significantly positivep+ and • negativep-asymmetries • unexpected largep- • role of unfavoured • fragmentation function? K+/-amplitudes consistent to p+/- • u-quark dominance: • CollinsFF similar for pions • and kaons ?

  18. PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 Sivers moments p+/-& K+/- • significantly positive p+ • and K+moments • K+ >p+in some bins  sea quarkcontribution to Sivers moment ? important ?

  19. Q2 Vector mesons (r, w, f): H E Pseudoscalar mesons (p, h): H E DVCS (g) depends on H, E, H, E Quantum number of final state selects different GPDs: ~ ~ ~ ~ t ( H + E) x dx =Jq = 1/2 DS+ Lz 10-30%(DIS) PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 hunting for Lq  hard exclusive processes: Generalised Parton Distributions Q2>>, t<< 

  20.  different charges: e+ e-(only @HERA!): DsUL polarisation observables: beam target PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 Deeply Virtual Compton Scattering DVCS-BH interference leads to non-zero azimuthal asymmetry I~Ds @HERMES: Dsc @nuclear targets , DsUT, DsLU

  21. PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 DVCS ALU on nuclear targets GPDs modification in nuclear matter: spatial distribution of energy, angular momentum and shear forces inside the nuclei [Guzey, Strikmann Phys.Rev.C68(2003)] Ne [Guzey,Siddikov,J.Phys.G32(2006)]  (1.85…1.95) for A=12…90 Kr

  22. PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 DVCS on nuclear targets GPDs modification in nuclear matter: spatial distribution of energy, angular momentum and shear forces inside the nuclei [Guzey, Strikmann Phys.Rev.C68(2003)] [Guzey,Siddikov,J.Phys.G32(2006)]  (1.85…1.95) for A=12…90 • small –t’:‘coherent enriched’ • large –t’:‘incoherent enriched’

  23. PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 DVCS on nuclear targets • ‘coherent enriched’ : 2s deviation from unity: 1.58±0.26 (>80% for all A>4He) …in good agreement with models

  24. exclusive r0 production PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 r ≠ 0 @SCHC g*-p CMS r° rest frame f p’ e’ p g* e r° p+ F q p- 15 unpolarised and 8 polarised Spin Density Matrix Elements rijkl <W>=4.8 GeV

  25. exclusive r0 production PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 unpolarised HERMES SDMEs compared to Zeus, H1 PRELIMINARY

  26. Delia Hasch spin Physics at Hermes Kyoto (Japan), 02-10-2006 HERMES view at the nucleon spin structure polarised DIS + HERMES: from unpolarised DIS first glimpse a0 =0.330±0.025(exp)  signals of GPDs  Ju+Jd transversity is non-zero! first T-odd DF in DIS direct flavour decomp. new constrain on Ds

  27. PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 Back-up slides

  28. PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 direct measurement of DG • golden channel: charm production • @HERMES: hadron production at high PT : direct, resolved, soft processes signal processes: PGF, QCD 22(g)

  29. PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 direct measurement of DG Monte Carlo vs Data: • Reason for disagreement at pT>1GeV: Increasing weight of NLO corrections K-factors for hard QCD subprocesses according to B. Jäger et. Al., Eur.Phys. J. C44(2005) 533

  30. PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 direct measurement of DG g/g Systematics • Uncertainties from each of 3 (4) groups • MC parameters • Pol./unpol. PDFs • Low-pT asymmetry • (Method 2 only) Fit function choice (1 or 2 params.) Summed linearly to “Models” uncertainty • Hopefully this conservative approach would also cover for the unknown uncertainties due to • Using a LO approximation • Using Pythia as a model • Experimental (stat.+syst.) added in quadrature • syst. uncertainty from 4% scaling uncertainty 14% on g/g

  31. PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 direct measurement of DG • functional forms: • fix g/gx for x0 • g/g1 for x1 (Brodsky et al.) • |g/g(x)|<1 for all x • …difference between functions is systematic uncertainty • light shaded area: range of data • dark shaded area: center of gravity for fit

  32. PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 what can we learn from Collins AUT? [Efremov et al. hep-ph/0603054] • h1 from cQSM • Collins FF: x-dependence: Hermes data fitted to obtain parameters for ansatz for CollinsFF z-dependence: BELLE data fitted and asymmetry for Hermes calculated • HERMES+BELLE data in agreement 

  33. PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 Sivers moments p+/- • significantly positive p+ • asymmetry • requires non-zero orbital angular momentum • first hint of naïve T-odd DF from DIS  test of universality: • D1 known  Sivers DF • can be extracted from • HERMES data !

  34. exclusive r0 production PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006 if SCHC holds (VM retains g* helicity): → at Q2 = 2 GeV2, sL=sT

  35. template PRC62 Delia Hasch Status report of Hermes Desy-Zeuthen Oct 23/24 2006

More Related