l
play

L s 2 s 1 Isospin I = | us > | ds > | us > | ds > - PowerPoint PPT Presentation

Feb 28, 2023 •242 likes •706 views

The qq model in a potential L s 2 s 1 Isospin I = | us > | ds > | us > | ds > Isospin = light meson spectrum | us > | ds > | us > | ds > S = 0 S = 1 L 0 1 2 0 1 Energy = Mass [MeV/c] K (1460) K 1 (B) K 0

  2. The qq model in a potential L s 2 s 1 Isospin I = ½ | us > | ds > | us > | ds >

  3. Isospin = ½ light meson spectrum | us > | ds > | us > | ds > S = 0 S = 1 L 0 1 2 0 1 Energy = Mass [MeV/c²] K (1460) K 1 (B) K 0 *(1430) K 2 *(1430) K 1 (A) K* (892) Kaon (494)

  4. Isospin = ½ light meson spectrum S = 0 S = 1 L 0 1 2 0 1 And many many more Energy = Mass [MeV/c²] K (1460) K 1 (B) K 0 *(1430) K 2 *(1430) K 1 (A) K* (892) Kaon (494) How do we produce those resonances?

  5. Diffractive dissociation into Κ − π + π − Κ − Κ − π + X π − t' R,P p target p recoil

  6. The measurement at COMPASS

  7. The COMPASS Spectrometer 2008/2009

  8. The COMPASS Spectrometer 2008/2009 Beam properties Beam properties Beam momentum 190 GeV/c Beam momentum 190 GeV/c Beam composition: Beam composition: π − : Κ − : p = 0.97 : 0.024 : 0.008 π − : Κ − : p = 0.97 : 0.024 : 0.008 � Up to 5 x 10 particles/s � Up to 5 x 10 particles/s beam

  9. The COMPASS Spectrometer 2008/2009 CEDAR detectors for CEDAR detectors for beam particle identification beam particle identification

  10. CEDAR particle identification Ce renkov D ifferential counter with A chromatic R ing Focus

  11. CEDAR particle identification Difference of the cherenkov ring radii of a pion and a kaon is below 0.1 mm at 190 GeV/c beam momentum !

  12. The COMPASS Spectrometer 2008/2009 Recoil proton detecto r Recoil proton detecto r around around 40 cm long lH2 target 40 cm long lH2 target

  13. The COMPASS Spectrometer 2008/2009 Recoil proton detecto r Recoil proton detecto r around around 40 cm long lH2 target 40 cm long lH2 target

  14. The COMPASS Spectrometer 2008/2009 RICH RICH

  15. The COMPASS Spectrometer 2008/2009 π K p

  16. Invariant mass distribution (K - π + π − ) Are those resonances decaying directly into 3 particles? ...

  17. Invariant mass distributions (K - π + ) and ( π + π − )

  18. RPD: determination of t' slopes data

  19. RPD: determination of t' slopes data data

  20. RPD: determination of t' slopes data fit data data

  21. RPD: determination of t' slopes data fit data data

  22. Determination of acceptance via MC

  23. Acceptance in the Κ − π + π − invariant mass

  25. Acceptance in the Gottfried Jackson frame

  26. Acceptance in the Gottfried Jackson frame

  27. Acceptance corrected partial wave analysis

  28. Acceptance corrected partial wave analysis

  29. The partial wave set

  30. The total intensity

  31. Spin totals

  32. Spin totals

  33. J P = 1 + waves

  34. J P = 2 - waves

  35. J P = 2 + waves

  36. J P = 0 - waves

  37. Summary and outlook Open strangness single diffractive mechanisms show resonant behavior � Those resonances are understood to be qq bar states with isospin ½ � The Κ − π + π − final state is shown to decay via substates � Tools of partial wave analysis (PWA) in the Ascoli approach are used to � determine resonances A mass independent acceptance corrected PWA fit was performed � Results are mostly in agreement with previous measurements but show � also also some interesting features For a final conclusion a mass dependent fit has to be performed � COMPASS is expected to double the number of events found in 2008 when � having reconstructed data of 2009

  38. Thank you!

  39. backup slides

  40. Measured strange meson level scheme

  41. resonances fitting the qq model

  42. Resonances as listed in the PDG review

  43. J P = 0 - waves

  44. J P = 1 + M=1 waves

  45. J P = 1 - waves

  46. J P = 2 - waves

Recommend

More recommend