7/318/1, 2009 A workshop on Hadron Physics@LZU, Lanzhou 1

Photoproduction of charged pions on deuteron

Yuncheng HAN(韩运成 ) for the NKS2 Collaboration

School of Nuclear Science and Technology, Lanzhou UniversityDepartment of Physics, Tohoku University

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Collaboration ListDepartment of Nuclear Science, Lanzhou University, China ,

Y.C. Han , T.S. Wang

Department of Physics, Tohoku University, Japan

N. Chiga, Y. Fujii, T.Fujibayashi, K. Futatsukawa, O. Hashimoto, K. Hosomi,

A. Iguchi, H. Kanda, M. Kaneta, M. Kawai, D. Kawama, T. Kawasaki, S. Kiyokawa,

T. Koike, Y. Ma, K. Maeda, N. Maruyama, M. Matsuzawa, A. Matsumura,

M. Mimori, Y. Miyagi, K. Miwa, S.N. Nakamura, Y. Okayasu, T. Otani,

K. Shirotori, H. Tamura, N. Terada, K. Tsukada, T. Yamamoto, K. Yokota

Laboratory of Nuclear Science, Tohoku University

K. Hirose, T. Ishikawa, H. Shimizu, K. Suzuki, T. Tamae, H. Yamazaki

Ichinoseki National College of Technology

O. Konno

Department of Electrical and Electric Engineering, Akita University,

A. Sasaki

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Content

Introduction Experimental setups Analysis and results Summary

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Study of pion photoproduction

Photoproduction on proton:

Locate and identify pion nucleon resonances. Photoproduction on neutron (deuteron):

Elementary production amplitude, isospin symmetry. Photoproduction on nuclei:

Modifications of the resonance excitation and their subsequent propagation and decay, brought by the nuclear medium.

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Motivation: d→pp, esp. NQF process

Quasi-Free process

Non Quasi-Free process

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Motivation: Study of d→np reaction

(uuu)

(ddd)

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Tagged Photon Beam at LNS-Tohoku

200 MeV electron beamfrom LINAC

Stretcher-Booster Ring Emax=1.2 GeV

Photon taggingsystem

Neutral KaonSpectrometer 2

Sweep magnet 0

5

m

Radiator

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Photon Tagging System

TaggerFinger

TaggerBackup

Radiator

Photon beam Electron beam on

carbon fiber Tagged by

scattering electron E=0.8-1.1 GeV

from 1.2 GeV mood electron beam mode

6 MeV coverage per tagging counter

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NKS2NKS2 Setup Setup

680 Dipole Magnet

LD2Target Cylindrical Drift Chamber (CDC) & Straw Drift Chamber (SDC)

Inner Hodoscope (IH)

& Outer Hodoscope (OH)

1 m

20 cm

Electron Veto Counter (EV)

Photon beam

Photon beam

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Analysis

Time selection Track selection Vertex position Particle Identify Channel selection for d→pp and d→ np

→ suppress accidental coincidence → suppress noisy of Drift Chamber→ target region select

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Channel selection of d→(pp)3Tr

For reconstructedd→pX mass Mmissing ,

0.8<Mmissing<1.1 (GeV/c2);

For reconstructedX→pp mass Mtarget ,

1.75<Mtarget<2.1 (GeV/c2);

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Channel selection of d→np

mx ~ mpeak±3; Px<0.2 GeV/c: quasi-free;

Px>0.3 GeV/c: non-quasi-free process;

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Sub-channel fitting for d→(np)NQF

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Calculation and various parameters

tann

t DAQ accep ce track

Y

N N

The cross section is obtained as,

Y is the yield,

N is the number of photon,

Nt is the effective deuteron target thickness,

εDAQ is efficiency of data acquisition system,

εaccptance is the acceptance decided by simulation.

εtrack is the efficiency of track reconstructing.

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Cross section of d→(pp)QF

Author E Bin/ MeV

Benz 100

Scheffler 25

Hirose 24

This work 6

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Cross section of d→(pp)NQF

300 MeV

Errors are 10%

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E calibration by d→(pp)3Tr

HAN Yun-Cheng, Wang Tie-Shan, et. al., Chin. Phys. C, Accepted

4-momentum conservation: L=L+Lp1+Lp2-Ld

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Comparison of d→

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Summary

Photoproduction d→pp and d→np are studied with tagged photons by using NKS2@LNS-Tohoku.

d→(pp)QF) agrees well with the previous obtained data.

we get d→(pp)NQF),and used to calibrate E; d→ ) are smaller than the previous obtained data

and theory study; In the future, differential cross sections will be studied, and

experiments in the lower energy region are scheduled.

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