ANALYZING POWER FOR QUASI-ELASTIC pp
SCATTERING IN CARBON AND FOR ELASTIC pp
SCATTERING ON FREE NUCLEONS
J. Bystricky, J. Deregel, J. Fontaine, T. Hasegawa, F. Lehar, A. De Lesquen,
C. Newsom, Y. Onel, A. Penzo, F. Perrot, et al.
To cite this version:
J. Bystricky, J. Deregel, J. Fontaine, T. Hasegawa, F. Lehar, et al.. ANALYZING POWER
FOR QUASI-ELASTIC pp SCATTERING IN CARBON AND FOR ELASTIC pp SCATTERING ON FREE NUCLEONS. Journal de Physique Colloques, 1985, 46 (C2), pp.C2-483-C2-484.
<10.1051/jphyscol:1985262>. <jpa-00224579>
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https://hal.archives-ouvertes.fr/jpa-00224579
Submitted on 1 Jan 1985
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JOURNAL DE PHYSIQUE
Colloque C2, supplément au n02, Tome 46, février 1985
page C2-483
A N A L Y Z I N G POWER FOR Q U A S I - E L A S T I C pp S C A T T E R I N G I N CARBON AND FOR
E L A S T I C pp S C A T T E R I N G ON FREE NLJCLEONS
J. Bvstricky., J. Deregel, J . M . onta aine*, T. ~asegawa**, F. Lehar,
A . d e Lesquen, C.R. ~ewsom', Y . Onelf+, A . PenzoA, F. P e r r o t * and
L. Van Rossum
DPhPE, CEN, Saclay, France
*DP~N/ME, CEK Saclay, France
**INS, Tokyo, Japan
UCLA, Los Angeles, U.S.A.
~ D P N C , U n i v e r s i t y of Geneva, SwitzerZand
INFN, T r i e s t e , I t a l y
+
Résumé - Le r a p p o r t d e s pouvoirs d ' a n a l y s e pour l a d i f f u s i o n q u a s M l a s t i q u e pp
dans l e carbone e t l a d i f f u s i o n é l a s t i q u e pp s u r l e s p r o t o n s l i b r e s a é t é mesur é e n t r e T = 0.52 e t 2.8 GeV en u t i l i s a n t l e f a i s c e a u d e p r o t o n s p o l a r i s é s d e
SATURNE II e t d e s c i b l e s CH2 e t d e carbone.
-
Abstract
The r a t i o of t h e a n a l y z i n g powers was measured from T = 0.52 t o 2.8
GeV by s c a t t e r i n g of t h e SATURNE IT p o l a r i z e d p r o t o n beam on carbon and CH
2'
We have measured t h e r a t i o of t h e a n a l y z i n g power Ap (C) f o r q u a s i - e l a s t i c s c a t t e r i n g
The measurements
of p o l a r i z e d p r o t o n s on p r o t o n s i n carbon t o t h e a n a f y z i n g power A
were c a r r i e d o u t w i t h t h e v e r t i c a l l y p o l a r i z e d p r o t o n beam from
II s c a t t e r e d
on t h e CH2 and carbon t a r g e t s of t h e "Nucleon-Nucleon" beam l i n e p o l a r i m e t e r . The ra) a s a f u n c t i o n of energy i s shown i n Fig. 1. It
t i o Epp(C) / E p p ( = A (C) / A
i s i n c r e a s i n g by a b o u t
from $ = 0.52 GeV t o = 0.85 GeV, and t h e n d e c r e a s i n g by
about 30% w i t h t h e energy i n c r e a s i n g up t o 2.8 GeV. No s i g n i f i c a n t d i f f e r e n c e i s observed between t h e r e s u l t s f o r two d i f f e r e n t a n g l e s a t 0.94 and 1 GeV, r e s p e c t i v e l y .
.
SAYERNE
88%
-
Fig. 1
Results f o r the r a t i o
€ p,(C) / E p p = App(C) / App
a s a f u n c t i o n of t h e k i n e t i c
energy.
It was known from p r e v i o u s experiments that t h i s r a t i o i s of t h e o r d e r of 0.5 i n t h e
r e g i o n of 0.6 t o 0.8 GeV. Note, t h a t t h e energy dependence f o r q u a s i - e l a s t i c s c a t t e r i n g o n carbon had n o t been measured b e f o r e above 1 GeV.
The observed e f f e c t was n o t expected £rom simple models wliich p r e d i c t f o r quasi-elast i c s c a t t e r i n g i n n u c l e i a monotonous i n c r e a s e , w i t h i n c r e a s i n g energy, approaching
a c o n s t a n t v a l u e s m a l l e r t h a n one.
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1985262
C2-484
JOURNAL DE PHYSIQUE
It s e a s r a t h e r n a t u r a l t o assume t h a t m u l t i p l e s c a t t e r i n g e f f e c t s i n t h e carbon nucl e u s , b e s i d e s a b s o r p t i o n , w i l l tend t o d e p o l a r i z e t h e i n c i d e n t p r o t o n beam. However,
t h e d e p o l a r i z a t i o n parameter f o r pp e l a s t i c s c a t t e r i n g is l a r g e and p o s i t i v e , of t h e
o r d e r of = 0.8 t o 0.9, i n t h e r a n g e of a n g l e s and e n e r g i e s c o n s i d e r e d h e r e . The observed s t r o n g d i f f e r e n c e i n t h e energy dependence between App and A (C) may b e a n
i n d i c a t i o n f o r a s p e c i f i c m u l t i p l e s c a t t e r i n g mechanism i n n u c l e i . TKPS could be t h e
c a s e , f o r i n s t a n c e , i f i n carbon t h e i n c i d e n t p r o t o n i s e x c i t e d i n a A i n t h e i n t e r mediate steps.