This work was supported by National Science Foundation Grants PHY 76-84033A01, PHY 78-22774, and Indiana Universit

Anderson, B.

Bainum, D.

Baldwin, A.

Foster, C.

Galonsky, A.I.

Goodman, C.D.

Goulding, C.

Horen, D.

Knudson, J.

Lind, D.

Madey, R.

Rapaport, J.

Satchler, G.R.

Schery, S.D.

Walker, G.

Watson, J.

Witten, T.

Zafiratos, C.

English

IUScholarWorks

(p ,n) EXPERIMENTS AT IUCF 
B. ~ n d e r s o n ,  * D. Bainum, ** A. ~ a l d w i n  ,* C.  Fos ter ,  A. I. ~ a l o n s k ~ ,  *** C .D. ~oodman, **** C. ~ o u l d i n ~  ,t 
D. Horen,**** J .  Knudson,* D. L ind , t t  R. Madey,* J .  Rapaport ,** G.R. Satchler,**** S .D. Schery , t t t  
G.  Walker, J. Watson," T. Witten,* and C.  ~ a f i r a t o s t t  
Early r e s u l t s  from t h e  (p,n) program show t h a t  The nuclear  s t r u c t u r e  r e l a t i onsh ips  between t h e  
t h e  (p,n) spec t r a  f o r  proton energies  above about 100 t a r g e t  s t a t e  and t h e v a r i o u s  f i n a l  s t a t e s  a r e  being 
MeV a r e  q u a l i t a t i v e l y  d i f f e r e n t  from those  f o r  proton explo i ted  t o  explore  s e l e c t i v e l y  p a r t i c u l a r  components 
energies  below about 40 MeV. I n  t he  low energy s p e c t r a  of t h e  nucleon-nucleon force .  It is assumed t h a t  t he  
t h e  most prominent f e a t u r e  is t h e  e x c i t a t i o n  of t h e  r eac t ion  is  d i r e c t  and t h a t  t h e  impulse approximation 
i soba r i c  analog s t a t e  (IAS). In t he  high energy is  va l id .  Thus, t he  fo rce  t h a t  gives r i s e  t o  t he  
spec t r a  t h e  most prominent f e a t u r e  is  t h e  sp in - f l i p  t r a n s i t i o n  is a component of t h e  N-N force .  
t r a n s i t i o n  (see  IUCF Technical and S c i e n t i f i c  ~ e ~ o r t ,  Trans i t ions  from self-conjugate 0+ t a r g e t  s t a t e s  
February 1, 1977 t o  January 31, 1978, p. 118).  t o  c e r t a i n  1+ f i n a l  s t a t e s  s e l e c t  a  fo rce  component of 
No new (p,n)  da t a  have been acquired i n  t h e  t h e  form (o l  02) ( T ~  r2). The c e n t r a l  term i n  OPEP 
present  repor t ing  period.  However, considerable has t h i s  form, and i f  OPEP is an important component 
progress has been made i n  i n t e r p r e t i n g  t h e  prel iminary of t h e  N-N fo rce ,  i t s  e f f e c t  should manifest i t s e l f  i n  
da ta .  In p a r t i c u l a r ,  two t h e o r e t i c a l  groups--W.G. t h e  e x c i t a t i o n  of t he se  s p e c i a l  1+ s t a t e s .  Examples 
Love and F. Petrovich,  and G.E. Walker and A. Pickle-  a r e  1 2 ~ ( p , n )  1 2 ~ ( g . s . )  and 2 8 ~ i ( p , n )  2 8 ~ ( 2 . 1  MeV). 
b 
simer--have developed r eac t ion  ca l cu l a t i ons  f o r  t h e  These s t a t e s  a r e  seen t o  s tand  out  prominently i n  t h e  
(p,n) da ta .  da ta .  
I 
Figure I .  Figure 2. 
With respect  t o  t h e  12c -+ 1 2 ~  t r a n s i t i o n  i t s  
analog,  1 2 ~ ( p , p ' )  12c(15.1 MeV), is r e l a t e d  by simple 
i sospin  coupling c o e f f i c i e n t s ,  and t h e  nucleon fo rce  
information can be ex t r ac t ed  a l s o  from t h e  (p ,p ' )  
da t a ,  assuming i sosp in  conservation.  A DWIA ca lcula-  
t i o n ,  due t o  W.G. Love, i n  which t h e  long-range p a r t  
of t h e  N-N p o t e n t i a l  is  assumed t o  be t h e  OPEP gives  
very good agreement with t h e  d a t a  (IUCF Technical and 
S c i e n t i f i c  Report, February 1, 1977 t o  January 31, 
1978, p. 93).  
Another s e t  of ca l cu l a t i ons  by G.E. Walker and 
A. Picklesimer,  compared wi th  (p,n) and (p ,p l )  d a t a  
a t  120 and 62 MeV, is shown i n  Figures 1 and 2 .  Here 
t h e  N-N i n t e r a c t i o n  is constructed from a g lobal  f i t  
t o  N-N s c a t t e r i n g  d a t a  over a wide energy range. A 
su rp r i s ing  aspect  of  t h e  ca l cu l a t i ons  is t h a t  t h e  f i t  
Figure  4.  
is good a t  62 MeV where t h e  impulse approximation is  
not  thought t o  be va l id .  
Figures 3 and 4 show ca l cu l a t i ons  by F. Pe t rovich  
and W.G. Love compared wi th  2 8 ~ i ( p , n ) 2 8 ~  and 
2 4 ~ g ( p , n ) 2 4 ~ 1  a t  62 MeV. In t hese  ca l cu l a t i ons  it 
was assumed t h a t  t h e  impulse approximation is n o t  
v a l i d  and an e f f e c t i v e  i n t e r a c t i o n  was generated by 
t h e  MSU G-matrix approach. l )  Although t h i s  i n t e r a c t i o n  
seems t o  overest imate t h e  c ros s  s e c t i o n ,  s t r u c t u r e  
d i f f e r ences  a r e  wel l  reproduced. Unpublished wave 
funct ions  obtained from B.H. Wildenthal and W. Chang 
were used. 
The beam swinger has now been i n s t a l l e d  i n  t h e  
northwest corner of t h e  IUCF bu i ld ing  and f l i g h t  pa ths  
a r e  now ou t s ide  t h e  bui ld ing ,  permi t t ing  de t ec to r  
l oca t ions  unobstructed by t h e  bui ld ing  s t r u c t u r e s .  
The use of 50 m and 100 m f l i g h t  paths is planned 
f o r  t h e  immediate fu tu re .  Polarized protons w i l l  
a l so  be used t o  measure asymmetries a s  an add i t iona l  
t e s t  of t he  in t e rac t ions .  
We thank W.G. Love, F. Petrovich,  G. Walker, 
and A. Picklesimer f o r  making t h e i r  ca l cu la t ions  
ava i l ab le  t o  us p r i o r  t o  publ ica t ion .  
* ~ e n t  S t a t e  Universi ty,  Kent, OH 44242 
**0hio Universi ty,  Athens, OH 43701 
* * * ~ i c h i ~ a n  S t a t e  Universi ty,  East Lansing, M I  48823 
****oak Ridge National Laboratory, Oak Ridge, TN 37830 
t Flor ida  A&M Universi ty,  Tallahassee,  FL 32303 
t ' f ~ n i v e r s i t ~  of Colorado, Boulder, CO 80309 
f i t  un ive r s i ty  of Texas, Galveston, TX 77550 
1)  G. Bertsch,  J. Borysowicz, H. McManus, and W.G. 
Love, Nucl. Phys. A284, 399 (1977). 


(p,n) Experiments at IUCF

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(p,n) Experiments at IUCF

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