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L(1405)/S(1385) Photoproduction in SLH2

L(1405)/S(1385) Photoproduction in SLH2. Deuk Soon Ahn. t-channel dynamics dominance. Basic assumption: At E γ ≈ 2 GeV, the γ p → K + π 0 Λ and γ p→K + π Σ reactions in the region of the Σ (1385) and the Λ (1405) resonances are largely driven by the K - t-channel exchange.

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L(1405)/S(1385) Photoproduction in SLH2

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  1. L(1405)/S(1385) Photoproduction in SLH2 Deuk Soon Ahn

  2. t-channel dynamics dominance Basic assumption: At Eγ≈ 2 GeV, the γ p → K+ π0 Λ and γ p→K+πΣ reactions in the region of the Σ(1385) and the Λ(1405) resonances are largely driven by the K- t-channel exchange. Nucl. Phys. A 748 (2005) 499 • t- channel dynamics, to gain understanding of the K-p-> π0Λ and of the K-p-> πΣ amplitudes below the KN thereshold, where they are dominated by the Σ(1385) and Λ(1405) resonances. • 2. Ingoing photon dissociates into real K+ and virtual K-, the off-shell K-scattering subsequently off the proton target to the dsigma/dt with increasing |t|. (t means the square of the 4 momentum transfer from the proton to the L(1405)and S(1385)) • 3. Theoretical differential cross sections for the γ p → K+ (π0Λ) and γ p → K+ (πΣ) reactions in the region of the Σ(1385) and the Λ(1405) resonances .(double kaon pole term contribution is large.)

  3. Old data: Production of hyperons by virtual photons T. Azemoon et al. NP B95 (1975) 77 e-p →e- K+ Y Y = Λ, Σ, Σ(1385), Λ(1405), Λ(1520) Rapid fall-off suggesting a t-channel exchange process

  4. The γ p → K+ π0Λ and γ p → K+πΣ cross sections as functions of the total πY center of mass energy for different values of Eγ w = (π Y) total center of mass energy

  5. Double pole term single pole term W=1.415 W=1.425 W=1.405 W=1.395 W=1.435

  6. Event Selction

  7. MissingMass –Z-vertex Cut Z-vertex , X-Vertex -1000<vtz<-900 -900<vtz<-800 -910<vtz<-900 -900<vtz<-890 -1200<vtz<-1100 -1100<vtz<-1000 X-vertx , Y-vertex in the target region for double track events. Coming from target cell. Because of extended size of photon beam spot@target, (especially in Hori) part of photon beam hit the target cell(Cu) and events produced from there.

  8. Photon energy spectrum for ntag=1or2 events by kato’sitagc.f Rejected events by tagcut using npl Shieding materials are placed in High electron E of tagger(corresponding Low photon energy). There remains possibility that recoil electron with high energy outside the range of tagger. Or produce the shower at the material. npl1=0or npl2=0 is the number of hits which is not associated in PL. (selected event for which is no other hit than recoil electron, at least one of two. Because of a few dead stripes in SSD layer. We allow there is no hit in these strips to save tracks passed these area.

  9. MissingMass & momemtum transfer Counts Counts MissingMass |t|-|t|min

  10. 0<|t|-|t|min<0.10 0.10<|t|-|t|min<0.20 0.20<|t|-|t|min<0.30 0.30<|t|-|t|min<0.40 0.40<|t|-|t|min<0.50 0.50<|t|-|t|min<0.60

  11. MissingMass –E18bins (E1.5-2.4) Counts/5MeV MissingMass(GeV/c^2)

  12. |t|-|t|min L(1116) K+MissingMass S(1193) S(1385)/ L(1116) L(1520) nonresont Photon Energy

  13. MMp(g,K+) – all T &T1-T5 cut 0.<|t|-|t|min<0.10 All |t|-|t|min 0.10<|t|-|t|min<0.20 0.20<|t|-|t|min<0.30 0.30<|t|-|t|min<0.40 0.40<|t|-|t|min<0.50 Eg(GeV)

  14. ds A * (NK+ -B) = dt NB * NT * dt Differential cross section • Minimum momemtum transfer |t|min varies drastically when photon energy changed. -> t’ = |t|-|t|min is introduced. • ds/dt’ =a (exp(-bt)) b : slope 　；　The yield which is corrected acceptance is fitted with exponential function • Photon normalization not included yet.

  15. Yields of L(1116) as function of|t|-|t|min , Data Counts |t|-|t|min

  16. Acceptance of L(1116) as function of |t|-|t|min , MC |t|-|t|min

  17. Differential Cross Section :Acceptance corrected yield|t|-|t|min distribution on L(1116) dsigma/dt (Abr.Unit.) |t|-|t|min

  18. Energy dependence of slope parameter b

  19. Yields of L(1405)/S(1385) |t|-|t|min , Data Counts |t|-|t|min

  20. Acceptance of L(1405) |t|-|t|min , MC |t|-|t|min

  21. Differential Cross Section of L(1405)/S(1385) dsigma/dt (Abr.Unit.) |t|-|t|min

  22. Energy dependence of slope parameter b

  23. Yields of L(1520) |t|-|t|min , Data Counts |t|-|t|min

  24. Acceptance of L(1520) |t|-|t|min , MC |t|-|t|min

  25. Differential Cross Section of L(1520) dsigma/dt (Abr.Unit.) |t|-|t|min

  26. Energy dependence of slope parameter b

  27. Acceptance-corrected t’ ; 1.35<MM<1.44(9 MMslice)&E1-E9 1.35<MM<1.36 1.36<MM<1.37 1.37<MM<1.38 1.38<MM<1.39 1.39<MM<1.40 1.40<MM<1.41

  28. 1.43<MM<1.44 1.41<MM<1.42 1.42<MM<1.43

  29. Energy dependence of slope parameter b 1.35<MM<1.36 1.36<MM<1.37 1.37<MM<1.38 1.38<MM<1.39 1.39<MM<1.40 1.40<MM<1.41

  30. 1.43<MM<1.44 1.42<MM<1.43 1.41<MM<1.42 b parameter

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