1. HLAB meeting status report Toshiyuki Gogami 3Sep2013

2. Contents K + Λ, K + Σ 0 cross section

3. 12 C(e,e’K + ) 12 Λ B Accidental background Quasi-free sΛsΛ pΛpΛ JLab E05-115, Carbon (112mg/cm 2 )

4. K + Λ, K + Σ 0 cross sections 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) JLab E91-016 : F. Dohrmann et al., arXiv 0707.3059v2 (2007) γ (*) + p  K + + Λ γ (*) + p  K + + Σ 0

5. Definition of the 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

6. Missing mass spectrum Polyethylene target (0.45 mg/cm 2 )

7. After B.G. subtraction

8. Hydrogen reduction correction Figure: An photograph before and after the beam irradiation on the targets.

9. H reduction factor & Run selection 76313 136.74 76314 136.74 76315 136.74 76316 138.74 76317 138.74 76318 140.74 76319 140.74 76320 142.74 76321 142.74 76322 186.2 76323 186.2 76324 186.2 76326 185.2 76327 185.2 76328 185.2 76329 185.2 76330 185.2 76331 185.2 76332 185.2 76333 185.2 76334 185.2 76335 185.2 76363 165.2 76365 163.2 76366 163.2 76367 161.2 76368 161.2 76369 159.2 76370 159.2 76371 157.2 76372 157.2 76373 155.2 76374 153.2 76375 153.2 76376 151.2 76377 151.2 76378 149.2 76564 148.74 76565 148.74 76566 148.74 76567 147.74 76568 147.74 76569 146.74 76570 146.74 76571 145.74 76572 145.74 76573 144.74 76574 144.74 76336 185.2 76337 185.2 76338 185.2 76339 185.2 76340 185.2 76341 176.2 76342 176.2 76343 175.2 76344 175.2 76346 175.2 76347 174.2 76348 174.2 76349 173.2 76350 173.2 76351 172.2 76352 172.2 76353 172.2 76354 170.2 76355 170.2 76356 169.2 76357 169.2 76358 168.2 76359 168.2 76360 167.2 76361 167.2 76362 165.2 /data/8d/gogami/MM/mm23/krd/lambda_reduction/targetpos/tpos2.dat Target positions from EPICS 78.6 ± 9.9 % @ 3649 μC

10. Angular and momentum acceptance HES HKS W~1.93 GeV Q2Q2 θ K lab  θ K CM

11. Results Θ lab e [rad]θ CM K [rad]Q 2 [GeV/c] 2 Λ (CMS) [nb/sr]Σ 0 (CMS) [nb/sr] 0.030-0.0500.270.003166 (17) (32)55 (29) (10) 0.050-0.0700.260.007155 (18) (29)51 (30) (10) 0.070-0.1000.270.013159 (18) (30)81 (29) (17) 0.030-0.1000.270.007164 (10) (31)78 (17) (15)

12. 12 Λ B g.s. from CH 2 target 52 (15) (4) nb/sr Polyethylene target 101 (4) (38) nb/sr in JLab E01-011

13. K + Λ, K + Σ 0 cross sections 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) JLab E91-016 : F. Dohrmann et al., arXiv 0707.3059v2 (2007) γ (*) + p  K + + Λ γ (*) + p  K + + Σ 0

14. Hidden factor, 2 ?

15. Paper of bucking coil to NIMA ( final procedure ) http://dx.doi.org/10.1016/j.nima.2013.08.047

16. Backup

17. Considered efficiencies Simulation 2012/9/14JPS meeting in Kyoto, Toshi Gogami17

18. Results Θ lab e [rad]θ CM K [rad]Q 2 [GeV/c] 2 Λ (CMS) [nb/sr]Σ 0 (CMS) [nb/sr] 0.030-0.0500.270.003166 (17) (32)55 (29) (10) 0.050-0.0700.260.007155 (18) (29)51 (30) (10) 0.070-0.1000.270.013159 (18) (30)81 (29) (17) 0.030-0.1000.270.007164 (10) (31)78 (17) (15) Θ lab e [rad]θ CM K [rad]Q 2 [GeV/c] 2 Λ (CMS) [nb/sr]Σ 0 (CMS) [nb/sr] 0.000-0.2500.200.007291 (32) (55)176 (12) (33) 0.000-0.2500.350.007176(12) (33)53 (24) (10) 0.000-0.2500.270.007198(12) (28)72 (20) (5)

19. Outlook Efficiencies Target burn Consistency check with H 2 O target 2013/3/27JPS meeting in Hiroshima, Toshi Gogami19 Before After Preliminary

20. Experimental setup 2013/3/27JPS meeting in Hiroshima, Toshi Gogami20

21. Electro-production of K + Λ JLab E05-115 experiment by the (e,e’K + ) reaction Small Q 2 ( ~0.01 [GeV/c] 2 )  almost real photon Real photon 2013/3/27JPS meeting in Hiroshima, Toshi Gogami21

22. e, e + background in GEANT simulation Vacuum chamber (sus304) NMR port (sus304) KDC1KDC2 e -, e + Generated particle : e + Distribution : spherical uniform Momentum : 860 – 1000 [MeV/c] Angle : 0 – 2 [mrad] 1000 events Number of e + (Simulation) B.G. mix rate (Real data) Correlation e + generated in target make HKS dirty JPS meeting in Kyoto, Toshi Gogami222012/9/14

23. Apply to u,v-layer Applied to uu’ and vv’ layers, too. Selective region determined by 1X and 2X Convert v v’-layer x x’-layer JPS meeting in Kyoto, Toshi Gogami232012/9/14

24. Hit wires event display (2) GREEN region Selective region RED markers & lines Selected hit wires BLACK markers & lines Rejected hit wires v v’ u u’u u’ x x’ v v’ u u’u u’ x x’ KDC1 KDC2 particle JPS meeting in Kyoto, Toshi Gogami242012/9/14

25. Energy scale calibration Λ の絵 解析のながれ e, K + conversion