1 / 19

π 0 -threshold measurements ( unpol. photons )

π 0 -threshold measurements ( unpol. photons ). Date : Sep-Oct 2007. Ebeam: 450.0 MeV. E γ : 130 – 420 MeV. NMR : 0.539456(run1), 0.538114 (run2). σ tot ( γ +p p+ π 0 ) run 1 & SAID. σ tot  σ tot * 1.05. σ tot ( γ +p p+ π 0 ) run 1 & SAID. two regions:

randi
Download Presentation

π 0 -threshold measurements ( unpol. photons )

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. π0-threshold measurements(unpol. photons) • Date : Sep-Oct 2007. • Ebeam: 450.0 MeV. • Eγ: 130 – 420 MeV. • NMR : 0.539456(run1), 0.538114 (run2).

  2. σtot (γ+pp+π0)run1 & SAID σtot σtot * 1.05

  3. σtot (γ+pp+π0)run1 & SAID two regions: high & low Eγ

  4. σtotat low & high Eγ low Eγ: shift ~ -2 MeV high Eγ: shift ~ +4 MeV

  5. Moeller scattering

  6. Background for Moeller:Triplet Electroproduction σ ~ Z2 two electrons – in Tagger, a positron – out.

  7. Detection of Moeller electrons in Tagger • Coincidence of two electrons: | T1 – T2 | < 1 ns • Difference of electrons energies: | E1 - E2 |> 10 MeV

  8. Moeller in Tagger

  9. 6 MeV shift of Moeller peak

  10. Tagger channel vs Moeller peak

  11. 3.5 MeV shiftin 2007 Jul2007, 1508 MeV Oct2007, 883 MeV

  12. 2.3 MeV shift in Jun2004(π0-threshold, linpol) radiator = Diamond Ebeam = 450 MeV

  13. Old Tagger measurements Radiator = Diamond Ebeam = 882 MeV Jul04, Sep04, Dec95

  14. shifted CB-data, SAID & MAID Control region: 165 – 175 MeV Shift: ~ 2 MeV

  15. shifted CB-data & TAPS Dec95 Fine step photon energies: no Microscope, just change Tagger field TAPS-95 : A.Schmidt, Mainz

  16. CB-data, SAID & MAIDnear threshold γ+pp+ξ (ξ γ γ ) Ethr=147.5 +/- 0.5 MeV  mξ=137.5 +/- 0.5 MeV

  17. Investigation of Taggerwith Moeller scattering • Tagger channels: 1 – 352. • Ebeam: 180, 450, 883, 1508 MeV. • Radiator: Diamond. • Beam current: 1nA, 10nA, 50nA.

  18. Attenuationlength of NaI PM AmBe ΝαΙ Eγ=4.44 MeV

  19. Attenuation length of NaI PM AmBe ΝαΙ AmBe Eγ=4.44 MeV

More Related