HLAB meetingstatus report Toshiyuki Gogami

3Sep2013

Contents

K+Λ, K+Σ0 cross section

12C(e,e’K+)12ΛB

Accidental background

Quasi-free

sΛpΛ

JLab E05-115, Carbon (112mg/cm2)

K+Λ , K+Σ0 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+ + Σ0

Definition of the cross section

Solid angle of HKSEvent by event

The number of VP• Including HES solid angle

and acceptance

Missing mass spectrum Polyethylene target (0.45 mg/cm2)

After B.G. subtraction

Hydrogen reduction correction

Figure: An photograph before and after the beam irradiation on the targets.

H reduction factor& Run selection

76313 136.7476314 136.7476315 136.7476316 138.7476317 138.7476318 140.7476319 140.7476320 142.7476321 142.7476322 186.276323 186.276324 186.276326 185.276327 185.276328 185.276329 185.276330 185.276331 185.276332 185.276333 185.276334 185.276335 185.2

76363 165.276365 163.276366 163.276367 161.276368 161.276369 159.276370 159.276371 157.276372 157.276373 155.276374 153.276375 153.276376 151.276377 151.276378 149.276564 148.7476565 148.7476566 148.7476567 147.7476568 147.7476569 146.7476570 146.7476571 145.7476572 145.7476573 144.7476574 144.74

76336 185.276337 185.276338 185.276339 185.276340 185.276341 176.276342 176.276343 175.276344 175.276346 175.276347 174.276348 174.276349 173.276350 173.276351 172.276352 172.276353 172.276354 170.276355 170.276356 169.276357 169.276358 168.276359 168.276360 167.276361 167.276362 165.2

/data/8d/gogami/MM/mm23/krd/lambda_reduction/targetpos/tpos2.dat

Target positions from EPICS

78.6 ± 9.9 % @ 3649 μC

Angular and momentum acceptance

HES HKS

W~1.93 GeV

Q2

θKlabθK

CM

Results

Θlabe [rad] θCM

K [rad] Q2 [GeV/c]2 Λ (CMS) [nb/sr] Σ0 (CMS) [nb/sr]

0.030-0.050 0.27 0.003 166 (17) (32) 55 (29) (10)

0.050-0.070 0.26 0.007 155 (18) (29) 51 (30) (10)

0.070-0.100 0.27 0.013 159 (18) (30) 81 (29) (17)

0.030-0.100 0.27 0.007 164 (10) (31) 78 (17) (15)

12ΛB g.s. from CH2 target

52 (15) (4) nb/sr

Polyethylene target

101 (4) (38) nb/sr in JLab E01-011

K+Λ , K+Σ0 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+ + Σ0

Hidden factor, 2 ?

Paper of bucking coil to NIMA( final procedure )

http://dx.doi.org/10.1016/j.nima.2013.08.047

Backup

Considered efficiencies

Simulation

2012/9/14 JPS meeting in Kyoto , Toshi Gogami 17

ResultsΘlab

e [rad] θCMK [rad] Q2 [GeV/c]2 Λ (CMS) [nb/sr] Σ0 (CMS) [nb/sr]

0.030-0.050 0.27 0.003 166 (17) (32) 55 (29) (10)

0.050-0.070 0.26 0.007 155 (18) (29) 51 (30) (10)

0.070-0.100 0.27 0.013 159 (18) (30) 81 (29) (17)

0.030-0.100 0.27 0.007 164 (10) (31) 78 (17) (15)

Θlabe [rad] θCM

K [rad] Q2 [GeV/c]2 Λ (CMS) [nb/sr] Σ0 (CMS) [nb/sr]

0.000-0.250 0.20 0.007 291 (32) (55) 176 (12) (33)

0.000-0.250 0.35 0.007 176(12) (33) 53 (24) (10)

0.000-0.250 0.27 0.007 198(12) (28) 72 (20) (5)

Outlook• Efficiencies• Target burn• Consistency check with H2O target

2013/3/27 JPS meeting in Hiroshima , Toshi Gogami 19

Before

After Preliminary

Experimental setup

2013/3/27 JPS meeting in Hiroshima , Toshi Gogami 20

Electro-production of K+Λ

JLab E05-115 experiment by the (e,e’K+) reactionSmall Q2 ( ~0.01 [GeV/c]2 ) almost real photon

Real photon

2013/3/27 JPS meeting in Hiroshima , Toshi Gogami 21

e , e+ background in GEANT simulation

Vacuum chamber(sus304)

NMR port(sus304)

KDC1 KDC2

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 Gogami 222012/9/14

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 Gogami 232012/9/14

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’

x x’

v v’ u u’

x x’

KDC1 KDC2particle particle

JPS meeting in Kyoto , Toshi Gogami 242012/9/14

Energy scale calibration

• Λの絵• 解析のながれ　

Angle, position @ FP

e, K+

Angle, momentum @ Target

6th order transfer matrix

conversion