SLIDE 1 Photoproduction of Eta Meson in Nuclear Target
- T. Kinoshita, at al, Phys. Lett. B639, 429 (2006)
- T. Maruyama，S. Chiba, P.T.P. 111, 229 (2004)
- T. Yorita, et al. Phys. Lett. B 76, 226 (2000)
§1 Introduction QMD Results and Recent Experimental Data §2 Model Relativistic Mean-Field Approach §3 Results §4 Summary and Conclusion
SLIDE 2
§1 Introduction
Reactions with Lepton : Probes Electron Scattering & Photo Reaction Purpose: Information of Nuclear Current photon absorption process Information Inclusive Reaction ⇒ Pure but Insufficient Amount Exclusive Reaction ⇒ Large Amount but Impure → Final State Interaction Collisional Processes of Observed Particles
Γ
Semi-Classical Numerical Simulation BUU, QMD
SLIDE 3
Quantum Molecular Dynamics （ QMD） 1） Single Events Semi-Classica Numerical Simulations 2） Classical Motions of Particles 3） Two Bosy Collionss ← Experimental Data Inelastic Collisions ： Ｎ ＋Ｎ⇔ Ｎ ＋Δ（ Ｎ
＊）
Particle Decays ： Δ（ Ｎ
＊）⇔ Ｎ
＋π 4) Describing Multi-Step Processes 5) Possible to Give Coincident Observables ( p, π) 6) Applicable to various Kinds of Reaction Photoreactions starting simulations at gamma-ray absorptted
SLIDE 4
SLIDE 5
SLIDE 6
Photoreaction
Total Photoabsorption Cross-Section ⇒ N*－Resonance Peaks disappear Medium Properties for N* Resonance ?
Total photoabsorption on nuclei Widths of D13(1520) and F15(1680) are broadened? How about other S11(1535) ?
SLIDE 7
SLIDE 8 §2 QMD Model
x p i L r x L
i i
e
x x x x
i i i i A
2 2 / 3 2
4 / ) ( ) 2 ( 1
) ( ), ( ) , , ( 1
| | ) , ; , ( , ,
1 1
H p p r r H r H dt dp p H dt dr
A A QMD i QMD i i QMD i
QMD = A-Body Classical Motion + 2-Body Collisions 1) Wave Function 2) Classical Motion Parts (Mean-Field Parts) 3) 2-Body Collisions ＋ Pauli Blocking
Elastic Collisons N + N ⇔ N + N Inelastic Collisons N + N ⇔ N + R (R + R)
4) Statistical Decay
SLIDE 9 Initial Distribution A nucleon absorps photon γ + N → Δ, N* 2 Body Col & Isobar Decay Elastic Collisions N + N ↔ N+R, R+R R ↔ N + π(η)
Classical Motions by mean-field
i QMD i i QMD i
r H dt dp p H dt dr ,
Statistical Decay Final Distribution
SLIDE 11 Analysis of QMD for 12C
63Cu 27Al 12C
KEK-Tanashi
MeV 150 MeV 210
T.Yorita, et al., Phys. Lett.B476 (2000) 226
SLIDE 12
§3 RMF approach
RMF approach : two kinds of Dirac Mean-Fileds Us ： attractive Scalar Fields Uμ：repulsive Vector Fields In-medium Properties for Nucleon are quite different from that in vacuum If in-medium corrections for N* are not so big, …. ? N* (vacuum) → N (medium) : big medium effects are seen ? unbound bound
T.Maruyama & S. Chiba, PTP 111 (2004) 229
N*– mean-fields
, ) ( *) ( s N U c N U
SLIDE 13 2 2 2
) ( ) ( 1 2
*
q p s n E p dp k p s k k
eff p p p i R eff i i
p
N*-width in Medium : Function of Phase Space
SLIDE 14 BUU calculations
- J. Lehr, M. Post, U. Mosel, Phys. Rev. C68 (2003) 044601
non-rela. calculation with Momentum-Dependent Potential N* ( high p weak pot. ) N ( low p, deep pot. )
SLIDE 15 §4 Q M D C a l c u l a t i
N eff
U s s
N*(unbound) → N (bound) Peak shift
SLIDE 16 πη
Jaegle et al., Proc. of NSTAR05
a new production process in high energy photon
SLIDE 17
SLIDE 18
Comparison with QMD
) ( *) ( N U N U
SLIDE 19
§5 Summary
Numerical Simulation Approaches fot Nuclear Reaction (BUU, QMD) are useful for study of Photoreaction Analyzing Final State Interaction γ + C, Cu → η + X No dramatic results Elementary Process γ+N → η + X , γ+N → πη +X U(S11) ≈ U(N) Future η + Nucleus Bound State Applying QMD to neutrino Reaction In-Medium Form Factor
M.K.Cheoun, K.C.Kim, K.Saito, T.Kajino, K.Tsushima, T.M., PRC, #065502 (13) M.K. Cheoun, K.S.Kim, H. Kim,W.Y. So, T.M.and T.Kajino, J.Phys.G (2014) in press
SLIDE 20
C ) MeV 500 ( Neutra Current Contribution Neutrino Reaction
Exp: MiniNOONE
M.K. Cheoun,et al. J.Phys.G (14) in press
SLIDE 21
SLIDE 22
Collision Broadening:
Γ(In-Med.)＝Γ(vac)＋Γcoll N* + N → N + N
L.A.Condratyuk, N.P. A579 (1994) 453
SLIDE 23
Pionphotoproduction and N*
SLIDE 24 Widthes of D13(1520) and F15(1680) are broadened? How about other N* Isobars?
KEK-Tanashi Experimets：γ＋A → η+ X Information of S11 Isobar Resonances QMD Analysis (Yorita et al.) Theory ⇔ Ecperimet
Width Γ(S11）= 150MeV Not Good Width Γ(S11）= 212MeV Good D13(1520) and F15(1680) Decay Processes are too Complicated
N N N N
*
S11(1535) Decay Process is Simple
N N N
*
Elementary Γ(S11）= 150MeV
