Φ-photo-production from deuteron M. Miyabe

Outlook Physics overview Study for FSI Improvement of Eγ Summary

3 Φ photo production of proton near the threshold High energy – Pomeron exchange – Increase with energy. Low energy – Pseudo scalar meson exchange – Decrease with energy. Discriminate natural-parity mode from meson exchange using Decay angular distribution. P, glueball, , f 2 ’   p Pure natural parity exchange Pure unnatural parity exchange 0   0  Decay angular distribution φ-Φ φ : photon pol. Angle Φ : K decay angle.

4 Results of proton target Peak structure around 2GeV. Natural parity exchange is dominant → 0 + glueball ? T. Mibe, et al. nucl-ex/

2005/09/21HAW055 Φ photo production of deuteron 1.Coherent production – Interact with deuteron itself. 2.Incoherent production – Interact with proton or neutron in deuteron.

2005/09/21HAW056 Incoherent production Due to isospin effect, – g πnn and g ηnn has opposite sign. →unnatural parity exchange process is suppressed in neutron case.  Information of unnatural (π/η) exchange process

Φ photo-production from neutron Exclude coherent contribution Final state interaction estimation Fermi motion effect

Final State Interaction (FSI) Enhancement in low PN relative momentum region. Try to make up the difference MC from Real data with FSI γ n p n p φ FSI

Theoretical calculation Enhancement factor – Triplet κ: deuteron binding parameter r 1 : NP effective radius – Singlet a 0 : NP scattering length r 0 : NP effective radius Ref: A.I. Titov arXiv:nucl-th/ v1 Singlet term has stronger dependent then triplet one

pn relative momentum Real dataMC(incoherent) γ n p n p φ P pn → k^2 PφPφ

Exposion FSI effect K^2 distribution |qfmin|<0.1After coherent exclusion Coherent Real MC(incohernt) FSI? Real-MC(co)

Comparison with theoretical function Ft(k) – ｒ 1 ← parameter fit Fit result – ｒ 1 = / fm Past experiment results – ｒ 1 = fm Real/MC

Singlet contribution F(k)= ε*Fs(k) + (1-ε)*Ft(k)  Prefer triplet function to singlet one?

FSI effect MMd W/O FSIMMd with FSI With FSI effect, ratio of coherent and incoherent was modified.

result χ^2Ratio of number of φ

Proton caseDeuteron case γ n p n p φ γ p p φ Fermi motion correction Eγ is directly related with s Eγ is not directory related with s Because of fermi motion

Minimum momentum for spectator nucleon Re-calculate Eγ variable in neutron rest frame γ n p n p φ n p CM n p Eγ in neutron rest frame

Scattered particle momentum Residual of scattered nucleus in MC qfmin<0.1 MC(incoherent)

Improvement of Eγ resolution MC simulation for incoherent Resolution of Eγ in the n rest frame value improve from 114MeV to 59MeV ΔEγ

Result Slope & dσ/dt in original EγSlope & dσ/dt in the n rest Eγ Preliminary

Summary Φ photo-production from neutron was unique tool for study unnatural parity exchange process. FSI contribution was found. Improvement resolution of γ energy in the n rest frame