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K* photoproduction from g11

K* photoproduction from g11. K. Hicks Ohio University HSG meeting, 12 June 2009. OUTLINE. Review of K* photoproduction data Theoretical interest Presentations of preliminary analysis (Ohio students). CLAS data (2007). I. Hleiqawi et al., Phys. Rev. C 76 (2007) 039905E. New Data.

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K* photoproduction from g11

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  1. K* photoproduction from g11 K. Hicks Ohio University HSG meeting, 12 June 2009

  2. OUTLINE • Review of K* photoproduction data • Theoretical interest • Presentations of preliminary analysis (Ohio students).

  3. CLAS data (2007) I. Hleiqawi et al., Phys. Rev. C 76 (2007) 039905E.

  4. New Data

  5. Comparison Red (open) = CLAS, Black (solid) = TAPS Note the strong forward-peaking of TAPS data at higher photon energies.

  6. K*+L (CLAS preliminary) L. Guo and D. Weygand, N* 2005 Conf., hep-ex/060101. K*+L shown by the RED points, quoted with 20% uncertainty.

  7. Theory calculations: K*0S+ Y. Oh and H. Kim, hep-ph/0605105. Model I (blue): no kappa form factor; Model II (red): with kappa form factor.

  8. Theory comparison: K*+L Y. Oh and H. Kim, PRC 73:065202 (2006). Full calculation (solid line) K+ t-channel only (dashed) Regge model (kaon trajectory)

  9. Theory: a) K*+L , b) K*0S+ Y. Oh and H. Kim, hep-ph/0605105. SOLID BLUE: no kappa form factor; DASHED RED: with kappa form factor

  10. New: K*+ Photoproduction • Analysis by Wei Tang (Ohio grad student) • Using g11 data set • Detecting: p+p- pair plus another p+. • Missing mass of Lambda and Sigma • Acceptance using fsgen + GSIM • Absolute normalization (new) • Checked using K+ photoproduction.

  11. Details on data and cuts • Runs 43526 – 44107 used (E=4.02 GeV). • Bad paddles were removed. • Photon identified using 1.0 ns time cuts. • Particle ID from SC and tagger time cuts. • Standard fiducial and vertex cuts applied. • Sideband subtraction to isolate K0 events. • K*+ mass cut from 0.80-0.98 GeV.

  12. Details on Normalization • Used gflux method to get photons. • Applied “trigger efficiency” map. • Mike Williams supplied this method. • Applied “dead time” correction. • INFN’s “current dependent correction” (18%) • No additional correction for start counter. • Lambda decay products not needed to fire the trigger (a la Mike McCracken).

  13. K0 mass peak

  14. K*+ Mass Left s.b. K0 peak K0 peak minus sidebands Right s.b.

  15. K*+ Missing Mass K*+ peak minus Sidebands.

  16. MM: one kinematic bin Eg=1.6-1.7 GeV and -1 < cosq < -.078

  17. MM: higher-E bin Eg = 2.3-2.4 GeV and -0.11 < cosq < 0.11

  18. Sample fit using gaussians

  19. gp  K*+L Cross Sections Units: mb Eg (GeV) W (GeV)

  20. Check: K0S+ cross sections

  21. Previous K0S+ data Eg = 1.65 GeV SAPHIR data (not shown) also published. B. Carnahan, PhD, Catholic U. (pub. in Sarantsev et al., Eur. Phys. J. A25, 411 (2005).

  22. Status of K*+ analysis • Preliminary differential cross sections OK. • Next step: systematic studies. • Just started: Lambda decay asymmetry • Statistics reduced by about ¼. • Plan: • Finish cross sections (1 month) • Preliminary Lambda asymmetries (1 month) • Write analysis note by end of summer.

  23. Status of K*0S+ analysis • This analysis is at a similar stage. • Normalization check requires more work • This is a “redo” of the published data. • I. Hleiqawi et al. (CLAS publication). • Overlap with nucleon resonances • Final state requires a PWA-like analysis. • This procedure was done for Hleiqawi data, but now we have good statistics!

  24. Summary • K*0 and K*+ final states are nearly final. • Normalization issues took a lot of time. • Good agreement with previous data, but much higher precision. • For K*+, can also do L asymmetry. • Plan to have analysis note by the end of the summer. • This will be part of the PhD thesis of W. Tang.

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