Let's see isospon (papars)
Let's See ISOSPIN !
アイソスピンを見よう！
簡単には見えないアイソスピン量子数も、良い分解能の(3He,t), (e,e'),
(n,p)タイプの実験結果の比較から、その麗しき姿をあらわすのであった。
"Isospin decomposition of the Gamow-Teller strength in 58Cu"
Physics Letters B 365 (1996) 29.
Abstract
The Gamow-Teller (GT) strength exicted by a (p,n)-type reaction
on a nucleus with isospin To and N > Z is shared by isospin
components To-1, To and To+1. A good energy resolution (3He,t)
reaction on 58Ni revealed the fine structure of the GT strength
in 58Cu. The isospin of each level constituting the fine
structure was assigned by comparing to results from inelastic
electron and proton scatterings and (n,p)-type reactions, thus
resolving the isospin structure of the GT strengths in 58Cu.
The ratio of the summed GT strengths among the three isospin
components is well described by a shell-model calculations.
N=Z核(T=0)のM1遷移がアイソスカラー型、アイソベクトル型に分離され、さらに
後者は、スピン成分と軌道成分へと、徹底的にM1遷移の性質が究明されていく。
"Isospin and spin-orbital structures of Jp=1+ states
excited in 28Si"
Physical Review C 55 (1997) 1137.
Abstract
Gamow-Teller (GT) states with Jp=1+ exicted by a (p,n)-type
charge exchange reaction on N=Z nuclei with ground-state isospin
T=0 have isospin T=1, while M1 states excited by inelastic
scattering of electrons or protons can have either T=0 or T=1.
The latter are the isobaric analog states of the GT states. By
comparing the GT states observed in the good-resolution (3He,t)
reaction at 150 MeV/nucleon with the M1 states obsrved in
inelastic electron and proton reactions, the isospin strucute of
the 1+ states in 28Si has been determined. From an analysis of
the strengths of corresponding 1+ states obsrved in the (3He,t)
and (e,e') reactions, the spin and orbital contributions to the
M1 excitations have been deduced.
同じアイソベクトル型の、M1遷移とガモウーテラー遷移へのメソン効果の
違いが、(3He,t) (e,e') の結果の差異から明らかにされていくのです。
"Mesonic effects deduced from good-resolution (3He,t)
reaction in comparison with inelasitc scatterings"
Nuclear Instruments and Methods in Physics Research A 402 (1998) 371.
Abstract
Gamow-Teller (GT) states excited by a charge-exchange reaction
on N = Z nuclei with ground-state isospin T = 0 have isospin
T = 1, while M1 states excited by inelastic scattering of
electrons or protons can have either T = 0 or T = 1. The latter
are the isobaric analog states of the GT states. By comparing
the GT states observed in the good-resolution (3He,t) reaction at
150 MeV/u with the M1 states observed in inelastic proton
reactions, the isospin of each 1+ state in 28Si was determined.
Furthermore, by comparing results from electron inelastic scattering
induced by electro-magnetic M1 operator, different response of
nucleus depending on different interaction is investigated.
Based on these comparisons among different probes, we discuss
1) the contribution of the ``$\Delta$-h excitation'' mechanism in
the quenching of magnetic excitations;
2) the effects of meson exchange currents; and
3) the orbital contribution in the $M1$ operator.
T＝1/2 の鏡映核においてアイソスピン対称性を仮定すると、M1遷移強度を、
アイソベクトル型の成分、アイソスカラー型の成分、及び、スピン型、軌道型
の成分へ分離できることを示しました。このような分離が可能であると言う
物理の面白さとともに、ニュートリノや、ダークマター検出器への応用が可能
です。鏡映核を検出器に使うと、中性流と荷電流が同時に測定出来、上記分離で
各成分の遷移マトリックスがわかったからです。
"Separation of isoscalar, isovector, orbital, and spin contributions
in M1 transitions in mirror nuclei"
Physical Review C 62 (2000) 044314.
Abstract
Experimental data for M1 matrix elements in the T=1/2 mirror nuclei
27Al and 27Si are used to determine the isoscalar and isovector
M1 components. The obtained isovector M1 matrix elements are
compared to the Gamow-Teller matrix elements deduced from $\beta$
decay and the 27Al(3He,t)27Si charge exchange reaction to determine
the contributions of the isovector spin and orbital components.
The exchange current effedts are taken into account. The results
are compared with shell model calculations.
次々に明らかにされるアイソスピンの世界。現在改良工事進行中。
........について掲載予定。