Supported by the National Science Foundation and Indiana Universit

Bacher, A.D.

Emery, G.T.

Foster, C.C.

Friesel, D.L.

Jones, W.P.

Nann, H.

Olmer, C.

English

IUScholarWorks

neutron channels. As noted by Gray, Tickle  and 
1 Bent t h e  two proton pick-up i n  t h e  Z r  reg ion  using 
t h e  ( 6 ~ i , 8 ~ )  r eac t ion  is u s e f u l  i n  studying t h e  proton 
conf igura t ions  of t h e  ground s t a t e  and f i r s t  exc i ted  
+ 0 s t a t e s .  They assume a simple d i r e c t ,  s ingle-  
s t e p  c l u s t e r  t r a n s f e r  and have ca l cu l a t ed  t h e  c ros s  
s ec t ions  us ing  a f i n i t e  range DWBA code. They f i n d  
good agreement between c a l c u l a t i o n  and experiment 
fo r  two-proton t r a n s f e r  t o  t h e  s p e c i f i c  s t a t e s .  
Our da t a  represent  i nc lus ive  t o t a l  c ros s  s ec t ions  f o r  
two-proton t r a n s f e r  t o  a l l  bound and neutron uns table  
s t a t e s  of 9 1 ~ .  Although t h e  a - t r ans fe r  r e a c t i o n  is  
poss ib l e  it is not  expected t o  con t r ibu t e  g r e a t l y  t o  
t he  Y i so tope  production. 
The most i n t e r e s t i n g  f e a t u r e  of t h e  da t a  i n  Fig. 1 
is t h e  s t e e p l y  r i s i n g  e x c i t a t i o n  funct ion  of 9 2 ~  
corresponding t o  t he  ( 7 ~ i ,  8 ~ )  r eac t ion  o r  two-proton 
t r a n s f e r  from t h e  t a r g e t  i n  conjunction with one 
neutron pick-up to t h e  t a r g e t .  A second poss ib l e  
mechanism could be t h e  double charge exchange (DCE) 
r e a c t i o n  (pp -+ nn) with subsequent neutron emiss-ions. 
Fur ther  ana lys i s  of t h e  d a t a  is requi red  before  we 
can es t imate  t h e  y i e l d  of 9 3 ~ ,  t h e  DCE product. 
Fur ther  work is planned a t  lower energies ,  i n  
p a r t i c u l a r  a t  about 60 and 75 MeV, i n  order  t o  ob ta in  
a cons i s t en t  s e t  of d a t a  between the  BNL and IUCF 
r e s u l t s .  Later ,  when h igher  energy 7 ~ i  beams become 
a v a i l a b l e  (ELi > 100 MeV), we hope t o  observe a 
marked increase  i n  t h e  c ros s  s ec t ions  of t h e  very 
neutron r i c h  y i so topes .  
1 )  R.S. Tickle ,  W.S. Gray and R.D. Bent, "Studies 
i n  t h e  Z r  Region us ing  the  ( 6 ~ i , 8 ~ )  Two proton 
Pick-up Reaction." IUCF Report 121 (1979). Also 
see  t h i s  annual r epo r t .  
SEARCH FOR 3p-3h STATES I N  THE A=12 AND 16 SYSTEMS WITH THE 
( 6 ~ i , t )  AND ( 6 ~ i ,  3 ~ e )  REACTIONS 
H .  Nann, A.D. Bacher, G.T. Emery, C.C. Fos ter ,  D.L. F r i e s e l ,  
W.P. Jones and C. O l m e r  
Indiana University CycZotron Facility,  BZoomington, Indiana 47405 
There has been a g rea t  d e a l  of i n t e r e s t ,  both ex- 3 ~ ( 6 ~ i ,  3 ~ e )  16N reac t ions .  S t a t e s  i n  160 a t  6.13, 
perimental  and t h e o r e t i c a l ,  i n  t h e  l oca t ion  of t h r e e  11.25, 14.40, 14.80, 20.80 and 24.80 MeV and s t a t e s  
pa r t i c l e - th ree  ho le  (3p-3h) s t a t e s  i n  12c-12B and i n  6~ a t  7.65, 9.81, 11.21, 11.81 and 14 .OO MeV a r e  
160-16~ .  We s t a r t e d  t o  search  f o r  t he se  s t a t e s  wi th  t h e  most s t rong ly  populated. Analog p a i r s  of s t a t e s  i n  
t h e  ( 6 ~ i , t )  and ( 6 ~ i , 3 ~ e )  r eac t ions  on 'Be and 13c a t  1 6 ~ - 1 6 0  a r e  c l e a r l y  seen. 
99 MeV bombarding energy. Due t o  t he  momentum m i s -  A simple weak-coupling c a l c u l a t i o n  us ing  t h e  
match between t h e  ent rance  and e x i t  channels and due method of B a n s a l - ~ r e n c h - ~ a m i c k l ' ~  p r e d i c t s  t he  cen t ro id  
t o  t he  geometrical  c o e f f i c i e n t s  i n  t he  s t r u c t u r e  of  t he  3p-3h s t a t e s  with T=O i n  160 of t h e  form 
+ 
amplitude, t he  t r a n s f e r  of a (d5/ 2)3=13/2 c l u s t e r  Is 13~(1 /2 - ,g . s . )  e 1 9 ~ ( 1 3 / 2  ,4.6) a t  around 15 MeV and 
favored. Hence, f i n a l  s t a t e s  with a conf igura t ion  of those  with T=l a t  around 20.5 MeV. This is approxima- 
] a r e  expected t o  be s t rong ly  [ (target) J (d5/2) J=13/2 t e l y  what is observed. The s t a t e  a t  20.80 MeV has  a 
exc i ted .  counterpar t  i n  and the re fo re  should have very l i k e l y  
Figure 1 shows spec t r a  of t he  3~ ( 6 ~ i ,  t ) 60 and T=l, whereas t h e  s t a t e s  a t  14.40 and 14.80 MeV have 
8 no counterparts, suggesting a T=O assignment. 
1) R. Bansal and J.B. French, Phys. Lett. 2, 145 (1964). 
2) L. Zamick, Phys. Lett. l9, 580 (1965). 
Ftquxe 1. Spectra for 1 6 ~ i ,  3 ~ e l  and 
I L i , t )  reactions on 3~ a t  15'. The 
energies i n  MeV of  various strongly 
excited s ta tes  are noted. 
CHANNEL NUMBER 


Search for 3p-3h States in the A=12 and 16 Systems with the (6-Li,t) and (6-Li,3-He) Reaction

https://scholarworks.iu.edu/dspace/bitstream/2022/2897/1/iucf_1979_104-105.pdf

Search for 3p-3h States in the A=12 and 16 Systems with the (6-Li,t) and (6-Li,3-He) Reaction

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