HYPERCHARGE EXCHANGE AMPLITUDE ANALYSES

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HYPERCHARGE EXCHANGE AMPLITUDE ANALYSES

M. Aguilar-Benitez

To cite this version:

M. Aguilar-Benitez. HYPERCHARGE EXCHANGE AMPLITUDE ANALYSES. Journal de

Physique Colloques, 1973, 34 (C1), pp.C1-301-C1-302. �10.1051/jphyscol:1973139�. �jpa-00215219�

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HYPERCHARGE

E f t c s m ~ ~

AMPLITUDE ANALYSES

HYPERCHARGE EXCHAAGE AMPLITUDE AVALYSES

M. AGUHAR-BENITEZ

J m t a d e E n e r g i a N u c l e a r M a d r i d

-

INTRODUCTION.-

From t h e e x p e r i m e n t a l p o i n t o f view t h e b a s i c a n d s i m p l e i d e a b e h i n d a m p l i t u d e a n a l y s e s is t h e d e t e r - m i n a t i o n o f t h e i n d i v i d u a l a m p l i t u d e s d e s c r i b i n g s t r o n g i n t e r a c t i o n r e a c t i o n s , u s i n g t h e d a t a i n m o d e l i n d e p e n d e n t manner. T h e p r o b l a n i n p e r f o r m i n g a c o m p l e t e a m p l i t u d e a n a l y s i s i s t h a t o n e n e e d s s p e - c i f i c p o l a r i z a t i o n i n f o r m a t i o n on a l l t h e p a r t i c l e s i n v o l v e d i n t h e p r o c e s s . I n t h e c a s e o f r e a c t i o n s i n - d u c e d by p s e u d o s c a l a r m e s o n s , t h i s r e q u i r e s t h e u s e of a p o l a r i z e d t a r g e t , t h e o b s e r v a t i o n o f t h e d e c a y p r o d u c t s o f t h e o u t q o i n g meson s t a t e a n d t h e m e a s y r e - ment o f t h e r e c o i l i n g b a r y o n p o l a r i z a t i o n . T h e g r e a t

a d v a n t a g e o f t h e h y p e r c h a r g e e x c h a n g e r e a c t i o n s [ w i t h a h y p e r c n in t h e f i n a l s t a t e h a v i n g a weak d e c a y 1 i s t h a t w i t h o u t t h e t a r g e t p o l a r i z a t i o n i n f o r m a t i o n o n e can e x t r a c t , f r o m t h e f u l l d e c a y c o r r e l a t i o n d a t a . 2n-2 q u a n t i t i e s f o r a r e a c t i o n d e s c r i b e d b y n a m p l i - t u d e s . I n t h e t r a n s v e r s i t y f r a m e s t h e s e q u m t i t i e s a r e t h e n m o d u l i a n d n-2 p h a s e s , a n d it i s p o s s i b l e t o p e r f o r m d e t a i l e d c o m p a r i s o n s w i t h t h e q u a r k m o d e l , SU(31 a n d d u a l i t y p r e d i c t i o n s a t t h e l e v e l o f t h e s e a m p l i t u d e p a r a m e t e r s .

1

.-

NEW RESULTS

.-

We p r e s e n t a b r i e f s u r v e y o f t h e c o n t r i b u t i o n s p r e s e n t e d a t t h e c o n f e r e n c e i n t h e domain o f h y p e r - c h a r g e e x c h a n g e r e a c t i o n s [ I ] .

1 . I

.-

THE REACTIONS K n +

n-A

a n d T-p ⁺K'A.

A p h m o m m o l o g i c a l model c o n s i s t m t w i t h f i n i t e m e r g y sum r u l e s a n d f i x e d - t d i s p e r s i o n r e l a t i o n s h a s b e m p r o p o s e d ( 2 1 . T h e c a l c u l a t e d a m p l i t u d e s re- p r o d u c e t h e e x p e r i m m t a l d i f f e r e h t i a l c r o s s s e c t i m o v e r a w i d e e n e r g y r m g e . However, t h e a g r e e m m t w i t h t h e p o l a r i z a t i o n d a t a is n o t y e t s a t i s f a c t o r y . T h e model h a s t h e c o r r e c t a b s o r p t i o n i m p l i c a t i o n s b u t m o r e e f f o r t [ b o t h e x p e r i m e n t a l l y a n d t h e o r e t i c a l l y ) is n e e d e d b e f o r e a good m d e r s t a n d i n g o f t h e s e two

l i n e r e v e r s e d r e a c t i o n s i s a c h i e v e d . I .2.- THE REACTION K-p ⁺n- Y*+ ( 1 3 a s 1

U s i n g t h e c o m b i n e d d a t a f r o m BML [ 3 ) . 13.9 a n d 4.6 G e v / c l a n d E c o l e P o l y t e c h n i q u e

-

S a c l a y ( 4 1 ( 7 . 9 5 G e v / c ) a r e m a l y s i s [ 5 1 o f t h i s r e a c t i o n h a s been p r e s e n t e d ( 6 ) . From a s a m p l e o f 6 0 0 e v e n t s t h e m o d u l i o f t h e 4 a m p l i t u d e s d e s c r i b i n g t h e p r o c e s s

[T3-l * T-l -1 * T i a T-31 1 a n d 2 r e l a t i v e p h a s e s h a v e b e m o b t a i n e d . The e x p e r i m s n t a l l y d e t e r m i n e d q u m t i - t i e s a p p r o x i m a t e l y s a t i s f y t h e q u a r k model e q u a l i t i e s

However, i n t h e f o r w a r d momm turn t r m sfer r e g i o n I

1

^t

' 1

< 0 . 3 GeV I d i s c r e p a n c i e s a t t h e l e v e l o f 2 t h r e e t o f o u r s t a n d a r d d e v i a t i o n s a r e o b s e r v e d in HT p-l-l a n d Im HTpg-l, A c a r e f u l d e t e r m i n a t i o n o f t h e h e l i c i t y d e n s i t y m a t r i x e l e m e n t s r e v e a l s o v e r a l l a g r e e m e n t w i t h t h e d u a l i t y p r e d i c t i o n o f p u r e l y r e a l h e l i c i t y a m p l i t u d e s . A g a i n , some d e v i a -

H H

t i o n s a r e o b s e r v e d i n Im p3-? a n d Im p3,, b u t c o n f i r m a t i o n i s n e e d e d .

1.3.- THE REACTION K-p + (w ,@I A a n d r - p -+ K*' N e w - d e t e r m i n a t i o n s o f t h e m o d t t l i o f t h e 6 t r a n s v e r - s i t y a m p l i t u d e s [ T:+,

TI+, TI:

^{o r A'.} ^,^'^B ^c') ^{a n d}

4 r e l a t i v e p h a s e s 8;-f m ~ t i c n ~ - o f t

'

, h a v e b e e n p r e - s e n t e d u s i n g t h e f o l l o w i n g d a t a s a m p l e s ( 6 1 ,[7) , ( E l .

T h e s e a n a l y s e s show 191 :

i 1 The m e a s u r e d a m p l i t u d e s s a t i s f y v e r y w e l l t h e q u a r k m o d e l ( o r SUI311 e q u a l i t i e s

~ y , ~ ( ~ - p -+ 641 = T : , ~ I ~ - ~ ⁺K'AI

ii) T h e r e a c t i o n K-p + @A 2nd K - ~ + "A e x h i b i t v e r y d i f f e r e n t a m p l i t u d e s t r u c t u r e .

i i i l T h e d a t a f o r K-p + wA a r e i n c o n s i s t e n t w i t h

" d u a l i t y + a b s o r p t i o n " p r e s c r i p t i o n o f p u r e l y r e a l

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1973139

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121-302 M

.

AGUILAR-BENITEZ

s i n ~ l e h e l i c i t y f l i p s - c h a n n e l a m p l i t u d e s . R e a c t i o n

P l a b (GeV/cl No. o f e v e n t s

1.4.- THE REACTION n-p -+ K* T O . -

From a s a m o l e o f 264 e v e n t s a t 3.93 GeV/c ( 8 ) t h e b e h a v i o u r of t h e a m p l i t u d e s ( h a v i n ~ t h e same s p i n s t r u c t u r e a s i n t h e 4 r e a c t i o n ) a s a f u n c t i o n o f t ' have been o b t a i n e d . A t t h e p r e s e n t s t a t i s t i c a l l e v e l o n e o f t h e two n a t u r a l p a r i t y exchange a m p l i t u d e s

( T ~ + I a p o e a r s t o be d o m i n a n t , i n c o n t r a d i s t i n c t i o n w i t h t h e n-p -+ K"\ r e a c t i o n .

The i n a d e q u a c y o f d a t a i n t h e r e l a t e d r e a c t i o n K-o -+ @cO o r e l u d e s a m e m i n q f u l t e s t o f t t t e q u a r k model e q u a l i t i e s

1 . 5 . - THE REACTION Y-o ^-+ p- ~ ~ ~ ( 1 3 8 5 1 A p r e l i m j n a r y d e t e r m i n a t i o n o f t h e a v e r a y e d v a l u e s ( i n t h e r a g e I t l l < 1 . 0 GeV 2 1 o f t h e 1 2 m o d u l i and 1 0 o h a s e s was p r e s e n t e d ( 1 0 ) u s i n g an a l m o s t back- q r o m d f r e e sample o f 44E e v e n t s a t 3.9 m d 4.6 C;eV/c.

The a m p l i t u d e s e x h i b i t f a i r a s r e e m m t w i t h t h e q u a r k mod p r e d i c t i o n s

m d t h e s i n p , l e ~ ~ ( 1 3 8 5 1 h e l i t i c i t y d e n s i t y m a t r i x e l e m e n t s a r e a p p r o x i m a t e l y r e a l , i n f a i r a g r e e m e n t w i t h t h e d u a l i t y p r e d i c t i o n .

K-p -+ w h

.-CONCLUSIONS.-

i l Amplitude a n a l y s e s a p o s a r t o b e a p o w e r f u l t o o l t o t e s t models e x h a u s t i v e l y .

i i ) More d a t a a r e n e e d e d .

i i i l I n f o r m a t i o n f r o m p o l a r i z e d t a r g e t e x p e r i m e n t s v e r y much welcomed.

i v l Very c o n v e n i e n t t o h a v e a more s y s t e m a t i c a p - p r o a c h i n r e c o n s t r u c t i n g t h e a m p l i t u d e s from t h e d a t a 1 1 1 ) .

K-p -+ 6 ?

3 . 9 + 3 . 9 5 + 4.6

%550 3 . 1 7 + 3 . 3

%BOO

REFERENCES

n-p -+ KXh

3 . 9 3

%420 3.9 + 3 . 9 5 + 4.6

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