1. HES HKS Analysis meeting 14/Dec/2012 @ JLab Toshi Gogami

2. Preliminary results of p(γ*,K + )Λ 2012/9/14JPS meeting in Kyoto, Toshi Gogami2 Preliminary JLab E05-115 (HES-HKS) 192±6±89 [ nb / sr ] SAPHIR : K.H.Glander et al., Eur. Phys. J. A 19, 251-273 (2004) CLAS : R.Bradford et al., Phys. Rev. C 73, 035202 (2006) ( JLab E05-115, Q 2 ~ 0.01 [GeV/c] 2 )

3. Definition of cross section Solid angle of HKS Event by event The number of VP Including HES solid angle and acceptance The number of VP Including HES solid angle and acceptance New way to estimate

4. VP flux factor Γ ( E e, ω, θ e’ ) Ee = 2.344 GeV ω = 1.5 GeV Jab E05-115, Polyethylene target θe ’ (lab)

5. VP flux factor vs. p and θ ~ 0.087 ~ 0.01 HES HKS

6. Integrated VP flux factor

7. VP flux factor Divided into 7 regions 1 3 4 5 2 Jab E05-115, Polyethylene target 67 θe ’ (lab)

8. VP flux factor Divided into 7 regions 1 3 4 5 2 Jab E05-115, Polyethylene target 0.0035 0.0043 0.0058 0.0081 0.0115 Q 2 [GeV] 2 67 0.0024 0.0160

9. Γ  Γ’ ( Region 4 ) SIMULATION 0.790 – 0.844 GeV/c ( 1.922 < W < 1.947 GeV) Γ’ ~ 3.5543× 10 -6 [ /N e ] Γ ~ 0.065 [ / GeV / sr / N e ] Number of VP ~ 6.2818×10 12 ± 4.05189×10 10

10. Results θe' (Lab)θgK (CM)Q 2 [GeV] 2 ΓΓ'Number of VPsolid angles (HES,HKS)[msr] NΛNΛ Cross section [ nb/sr ] 0.030 - 0.0400.306 0.312±0.08 0.0024 2.45e-3±5.9e-4 0.2214.27923e-067.52071e+12±1. 05573e+11 0.3, 8.4384 +- 24206.161 ( +- 13.1462 ) ( - 96.8266 ) ( + 97.1458 ) 0.040 - 0.0450.298 0.305±0.08 0.0035 3.54e-3±2.6e-4 0.1502.34783e-064.18425e+12 ±4.29365e+10 0.3, 8.4149 +- 17144.837 ( +- 16.5421 ) ( - 61.9157 ) ( + 62.1365 ) 0.045 - 0.0500.309 0.307±0.07 0.0043 4.30e-3±3.2e-4 0.1212.25936e-063.98002e+12 ±4.30705e+10 0.3, 8.4142 +- 17144.097 ( +- 17.6952 ) ( - 60.6333 ) ( + 60.8523 ) 0.050 - 0.0600.298 0.298±0.08 0.0058 5.85e-3±8.3e-4 0.0904.10857e-067.20095e+12 ±6.46153e+10 0.8, 8.4300 +- 24169.896 ( +- 13.671 ) ( - 77.3213 ) ( + 77.5833 ) 0.060 - 0.0700.312 0.312±0.09 0.0081 8.02±9.4e-4 0.0653.5543e-066.26988e+12 ±3.97629e+10 1.0, 8.4307 +- 24199.578 ( +- 15.6367 ) ( - 91.1819 ) ( + 91.4899 ) 0.070 - 0.0850.316 0.312±0.08 0.0115 1.129e- 2±1.629e-3 0.0464.50219e-067.80142e+12 ±6.16911e+10 1.8, 8.4378 +- 27196.161 ( +- 14.4697 ) ( - 90.3967 ) ( + 90.6998 ) 0.085 - 0.1000.300 0.306±0.09 0.0160 1.593e- 2±1.600e-3 0.0332.7764e-064.78124e+12±9. 17287e+10 1.6, 8.4215 +- 20181.798 ( +- 17.2207 ) ( - 80.6174 ) ( + 80.8964 )

11. Angular dependence SAPHIR : K.H.Glander et al., Eur. Phys. J. A 19, 251-273 (2004) CLAS : R.Bradford et al., Phys. Rev. C 73, 035202 (2006)

12. Q 2 dependence

13. SAPHIR : K.H.Glander et al., Eur. Phys. J. A 19, 251-273 (2004)

15. Coincidence cut for 52 Cr TCut cut_1 = "abs(ctime+54.6)<1.0 && 75976.5<runnum && runnum<76049.5"; TCut cut_2 = “abs(ctime+54.8)<1.0 && 76716.5<runnum && runnum<76802.5"; TCut cut_3 = "abs(htimetar-etimetar+54.9)<1.0 && (76845.5<runnum && runnum<76937.5)"; TCut cut_41 = "abs(htimetar-etimetar+54.9)<1.0 && (76947.5<runnum && runnum<77064.5)"; TCut cut_42 = "abs(htimetar-etimetar+54.3) 77064.5)";

16. END

17. Comparison with data of JLab Hall-A Large longitudinal term contributions? p(γ*,K + )Λ ~ JLab E05-115 (HES-HKS) W ~ 1.9 GeV Q 2 ~ 0.01 [GeV/c] 2 p(γ*,K + )Λ ~ JLab E05-115 (HES-HKS) W ~ 1.9 GeV Q 2 ~ 0.01 [GeV/c] 2 Preliminary p(γ*,K + )Λ ~ JLab E94-107 W ~ 2.2 GeV Q 2 ~ 0.07 [GeV/c] 2 p(γ*,K + )Λ ~ JLab E94-107 W ~ 2.2 GeV Q 2 ~ 0.07 [GeV/c] 2 SAPHIR : K.H.Glander et al., Eur. Phys. J. A 19, 251-273 (2004) CLAS : R.Bradford et al., Phys. Rev. C 73, 035202 (2006) JLab E94-107 : P.Markoviz et al., Proceedings of SENDAI08 (2009) 2012/9/14JPS meeting in Kyoto, Toshi Gogami17

18. Considered efficiencies Simulation 2012/9/14JPS meeting in Kyoto, Toshi Gogami18

19. K + production at small angles electroproduction SL: 0.41 = 0.35 + 0.004  0.001 + 0.06 (  = 0.7 ) a steep Q 2 dependence ? P. Bydzovsky’s presentation at ECT* 2011 (  *,K + ) JLab Hall-A E05-115 W=1.9 GeV Q 2 =0.01 (GeV/c) 2 2012/9/14JPS meeting in Kyoto, Toshi Gogami 19