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HES-HKS analysis meeting 30 Aug 2013 Toshiyuki Gogami

HES-HKS analysis meeting

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HES-HKS analysis meeting. 30 Aug 2013 Toshiyuki Gogami. Contents. Cross section of elementary processes Introduction Correction factors K + decay factor H reduction Results Bucking coil. K + Λ , K + Σ 0 cross sections. Preliminary 85 ± 13 ±34. Preliminary 200 ± 16 ± 91. - PowerPoint PPT Presentation

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Page 1: HES-HKS analysis meeting

HES-HKS analysis meeting30 Aug 2013

Toshiyuki Gogami

Page 2: HES-HKS analysis meeting

Contents

• Cross section of elementary processes– Introduction– Correction factors• K+ decay factor • H reduction • Results

• Bucking coil

Page 3: HES-HKS analysis meeting

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

Preliminary 200 ± 16 ± 91

Preliminary 85 ± 13 ±34

Page 4: HES-HKS analysis meeting

Angular and momentum acceptance

HES HKS

W~1.93 GeV

Q2

θKlabθK

CM

Page 5: HES-HKS analysis meeting

Definition of cross section

Solid angle of HKSEvent by event

The number of VP• Including HES solid angle

and acceptance

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K+ decay factor

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Hydrogen reduction correction

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

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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 position from EPICS

78.6 ± 9.9 %

Page 9: HES-HKS analysis meeting

Procedure

1. One W bin ( W~1.93 GeV )2. Three Q2 bins ( W~1.93 GeV )3. Two angular bins ( W~1.93 GeV )

An original ROOT file 1. Add necessary information

• Jacobian , HKS solid angle, K+ decay factor2. Derive the QF background shape from 12C data3. Subtract the background shape4. Estimate virtual photon (flux) by a Geant4 simulation5. Calculate the cross section with efficiencies and

correction factors

Page 10: HES-HKS analysis meeting

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)

Page 11: HES-HKS analysis meeting

12ΛB g.s. from CH2 target

52 (15) (4) nb/sr

Polyethylene target

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

Page 12: HES-HKS analysis meeting

Hidden factor, 2 ?

Page 13: HES-HKS analysis meeting

Paper of bucking coil to NIMA( final procedure )

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

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Backup

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Energy loss

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K+ absorption factor

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Trigger efficiency

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Charge distribution

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H reduction