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HIGH ENERGY EXPERIMENTAL AND
THEORETICAL WORKSHOP : EXPERIMENTAL SUMMARY
D. Crabb
To cite this version:
D. Crabb. HIGH ENERGY EXPERIMENTAL AND THEORETICAL WORKSHOP : EX- PERIMENTAL SUMMARY. Journal de Physique Colloques, 1985, 46 (C2), pp.C2-287-C2-288.
�10.1051/jphyscol:1985233�. �jpa-00224547�
JOURNAL DE PHYSIQUE
Colloque C2, suppldment a u n02, Tome 46, fevrier 1985 page C2-287
H I G H ENERGY EXPERIMENTAL AND THEORETICAL WORKSHOP : EXPERIMENTAL SUMMARY
D.G. Crabb
Randal2 Laboratory, University o f Michigan, Ann Arbor, Michigan, U.S.A.
The High Energy Experimental and T h e o r e t i c a l Spin P h y s i c s Workshop was d i v i d e d i n t o t h r e e main t o p i c s i n which both e x p e r i m e n t a l and t h e o r e t i c a l p a p e r s were p r e s e n t e d f o r d i s c u s s i o n . The t o p i c s were:
1. Large PT
2. Medium and s m a l l PT 3. General and C o l l i d e r
A t o t a l of f i f t e e n p a p e r s were p r e s e n t e d of which o n l y t h r e e were on experiment.
T h i s was r a t h e r d i s a p p o i n t i n g t o t h e workshop o r g a n i z e r s and we can only hope t h a t t h i s i s a l u l l i n t h e p r o d u c t i v i t y of t h e f i e l d .
The t h r e e experiments p r e s e n t e d were a s f o l l o w s :
1. A n a l y s i s of t h e R e a c t i o n n-p + n-n+n a t High It 1,
ACCMOR C o l l a b o r a t i o n . P r e s e n t e d by I. S a k r e j d a 2. P o l a r i z a t i o n of A Hyperons i n K-P I n t e r a c t i o n s .
Aachen-Berlin-Bombay-CERN-Cracow-Innsbruck-Jamm-London-Vienna-Warsaw C o l l a b o r a t i o n . P r e s e n t e d by T. Haupt.
3. Spin E f f e c t s i n pp E l a s t i c S c a t t e r i n g a t High Energy
Michigan-BNL-Maryland-Notre Dame-Rice-Texas A&M-ETH C o l l a b o r a t i o n . Pre- s e n t e d by R. Raymond
Though a l l t h r e e were hadron e x p e r i m e n t s , each covered v e r y d i f f e r e n t a r e a s of i n t e r - e s t . Each experiment was d i s c u s s e d i n d e t a i l i n t h e s e proceedings. So h e r e I w i l l g i v e only a b r i e f summary of each one.
1. This experiment s t u d i e d t h e r e a c t i o n n-p + n+n-n a t 17 GeV ( w i t h l i q u i d hydrogen and p o l a r i z e d p r o t o n t a r g e t s ) and 63 G e V ( w i t h l i q u i d hydrogen t a r g e t ) .
A d e t a i l e d p a r t i a l wave a n a l y s i s shows t h a t f o r -t > 0.2 ( G ~ v / c ) ~ t h e r e i s e v i - dence f o r a J"= 2* meson s t a t e a t I-$+,,- - 840 MeV. Various kinematic and non-reso- n a n t e f f e c t s were e x p l o r e d b u t could n o t reproduce t h e observed e f f e c t . Consequently t h e s t a t e i s claimed a s a new p h y s i c a l o b j e c t but w i t h no obvious e x p l a n a t i o n a s i t does n o t f i t i n t o any p a r t i c l e schemes.
2. The p o l a r i z a t i o n of t h e A " produced i n t h e r e a c t i o n K-p + A 0 + a n y t h i n g a t 110 GeV/c was s t u d i e d w i t h 985 e v e n t s from BEBC. It was assumed t h a t a s s o c i a t e d produc- t i o n i s t h e dominant c h a n n e l i n t h e A 0 i n c l u s i v e c r o s s s e c t i o n .
The d a t a were compared w i t h d a t a a t lower e n e r g i e s i n which A 0 were produced i n r e a c t i o n s induced by non-strange p r o j e c t i l e s and Kf. The c o n c l u s i o n s were:
a. I n c k e a s i n g n e g a t i v e p o l a r i z a t i o n s w i t h i n c r e a s i n g PT i n g e n e r a l agreement w i t h o t h e r d a t a .
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1985233
C2-288 JOURNAL DE PHYSIQUE
b. L i t t l e dependence on XF and s m a l l p o l a r i z a t i o n s , a g a i n i n agreement w i t h o t h e r d a t a .
3. I n t h i s experiment t h e a n a l y z i n pownr i n p 4 e l a s t i c s c a t t e r i n g a t 28 GeV/c h a s been s t u d i e d o u t t o P: = 6.6 ( & V / C ) ~ . Above PF I (&v/c)' t h e a n a l y z i n g power t e n d s t o l a r g e p o s i t i v e v a l u e s c u l m i n a t i n g i n a v a l u e o f 51 f 17% a t P: = 6.6 (&v/c)'.
T h i s p a p e r g e n e r a t e d t h e most t h e o r e t i c a l d i s c u s s i o n and f o u r of t h e t h e o r y p a p e r s p r e s e n t e d a t t h e workshop addressed t h i s r e s u l t . Much of t h e d i s c u s s i o n cen- t e r e d around t h e impact of t h e l a r g e a n a l y z i n g power on P e r t u b a t i v e QCD c a l c u l a t i o n s i n which t h e a n a l y z i n g power must be zero. These c o n t r i b u t i o n s are d i s c u s s e d i n t h e t h e o r y s e c t i o n of t h e workshop.
