RESULTS OF THE 3-MESON SYSTEM PARTIAL WAVE ANALYSIS

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Submitted on 1 Jan 1973

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RESULTS OF THE 3-MESON SYSTEM PARTIAL WAVE ANALYSIS

G. Otter

To cite this version:

G. Otter. RESULTS OF THE 3-MESON SYSTEM PARTIAL WAVE ANALYSIS. Journal de Physique Colloques, 1973, 34 (C1), pp.C1-233-C1-234. �10.1051/jphyscol:1973126�. �jpa-00215206�

RESULTS OF THE 34ESON SYSTEM PARTIAL WAVE ANALYSIS

RESULTS OF THE 3-MESON. SYSTEM PARTIAL WAVE ANALYSIS

G, OTTER

P h y s i k a l i s c h e s I n s t i t u t , ^Aachen

The I l l i n o i s group i n t r o d u c e d a powerful method of-

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performing a p a r t i a l wave a n a l y s i s of t h e (x+xfx*)- system [1,2,3], r e f e r r e d a s t h e A s c o l i p a r t i a l wave a n a l y s i s .

J.D. Hansen e t a l . [ 4 ] submitted a paper t o t h i s Conference, i n which a d e t a i l e d d e s c r i p t i o n of t h i s a n a l y s i s and of t h e p h y s i c a l assumptions used, i s given f o r any r e a c t i o n of t h e t y p e : pseudoscalar meson + nucleon ( n u c l e u s ) + nucleon ( n u c l e u s ) + 3 p s e u d o s c a l a r mesons. I t i s shown t h a t with s m a l l mo- d i f i c a t i o n s t h e method c a n be a p p l i e d t o t h e study of s p e c i a l 4-meson systems (e.g. t h e Ku+system).

The CERN- Serpukhov c o l l a b o r a t i o n i n v e s t i g a t e d t h e r e a c t i o n L p + {x'x-p a t 25 and 40 GeV/c w i t h t h e CERN-IHEP boson-spectrometer [5,6 1. They f i n d t h a t i n t h e mass r a n g e of t h e 3-meson system from 1.0 t o 2.0 GeV t h r e e waves a r e dominant : t h e (px) I'SO- wave ( s p i n - p a r i t y - o r b i t a l a n g u l a r momentum between

p and 7; t h i r d component of t h e s p i n i n t h e Jackson frame), which i s peaked a t about 1.15 GeV with a width of .30 GeV - t h e A1, t h e ( px) 2+~1-wave ( w i t h mass M = 1.315 2 ^{.005 GeV} and width T= .115+ .015 GeV

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A l l t h r e e enhancements a r e produced by n a t u r a l p a r i - t y exchange. The A1 and A3 cannot be d e s c r i b e d by Breit-1Yigner amplitudes [ 7 ] , whereas t h e A c a n be

2 d e s c r i b e d by it. The A and e s p e c i a l l y t h e Ag show

1

s m a l l b u t s i g n i f i c a n t d e v i a t i o n s from TCHC. The den- s i t y m a t r i x f o r t h e A2 decaying v i a px i s compatible w i t h t h a t f o r t h e a l t e r n a t i v e decay i n t o q x [a]. ^{A l -}

though t h e Al ,A3 and A2 have d i f f e r e n t p r o p e r t i e s , t h e energy dependence of t h e p r o d u c t i o n c r o s s - s e c t i o n i s s i m i l a r .

The CERN-ETH Z u r i c h - H i l a n o c o l l a b o r a t i o n presen- t e d a p r e l i m i n a r y s p i n - p a r i t y a n a l y s i s of t h e cohe- r e n t l y produced ( 3 ~ ) - s y s t e m on n u c l e i . They s t u d i e d t h e r e a c t i o n X N + ( F ~ + < ) N a t 8.9 and 15.1 GeV/c.

A predominance of t h e 1' s t a t e w i t h some admixture of 0- i s found i n t h e A r e g i o n . When t h e t o t a l sam-

1

p l e of e v e n t s was d i v i d e d i n t o subsamples a c c o r d i n g

t o t h e mass of t h e t a r g e t nucleus, namely l i g h t (Be, C, A l , S i ) , medium ( T i , Cn) and heavy (Ag, Ta, Pb) n u c l e i , a s y s t e m a t i c d e c r e a s e of t h e p e r c e n t a g e of t h e 0- s t a t e with i n c r e a s i n g mass of t h e n u c l e i was observed. T h i s d e c r e a s e amounts t o about a f a c t o r of 2 going from t h e l i g h t t o t h e heavy n u c l e i .

The ABCLV-collaboration p r e s e n t e d a paper on t h e p a r t i a l wave a n a l y s i s of t h e ( ~ - 7 ~ ~ x - l system pro- duced i n t h e r e a c t i o n K - ~ + ~ - x + < p a t 10 and 16 G e V / c i n a n hydrogen bubble chamber. The ( K m ) system i s f.ound t o be produced mainly i n a s t a t e of unnatu- r a l p a r i t y with M = 0 i n t h e Gottfried-Jackson sys- tem ( t h e r e a r e however small but s y s t e m a t i c devia- t i o n s from TCHC) and by t h e exchange of an o b j e c t of n a t u r a l p a r i t y . From t h e e i g e n v a l u e s of t h e gene- r a l i z e d d e n s i t y m a t r i x elements, i t i s seen t h a t both p r o t o n - s p i n - f l i p and spin-non-flip amplitudes c o n t r i b u t e t o t h e p r o d u c t i o n of t h e (Kxx) system.

The c o n t r i b u t i o n of t h e v a r i o u s s p i n - s t a t e s i s shown i n f i g u r e 1.

K ~ K T - T ~ ol 10. ond 16 GeV/c tbp < 0.8 G ~ V '

1.0 14 18 2.2 10 1.4 : 8 2 2

M ( K n l r ) GeV

F i g . 1.

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A dominant 1 + ~ 0 - w a v e i s seen (I'D -wave c o n t r i b u e e s v e r y l i t t l e ) mainly c o n s i s t i n g of 8 P90 7t

.

400-

2

J FLAT .

d) .

0.tt.tt.tf.1-t.t-i.1~

' 0 - 0 ' . 01 -

29- -

e) .

0-+>*A+. : : : -

2.0-

'.+

','. ,.'*...-

2'1' 200.

- 200-

Z W

800- 200

I*O* - 0

0 b)

B ^200-

400- Z

200.

0 : : : - . .

too-

f

I* I*

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c) .

0 L t - L

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:.

{

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0

200. 2-0' .

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1973126

C1-234 G. OTTER

l a r g e K p c o n t r i b u t i o n s with a c o n s t r u c t i v e Kp/K890x * t e n t w i t h a c o n s t a n t value. I n t h e L-region t h e i n t e r f e r e n c e a r e found. The 1' (KEg07c) decay mode ( c q W x ) system i s dominantly 2-. The peak of t h e p e a k s around 1300 MeV and h a s a width of about 350 2- s t a t e i s roughly a s wide a s t h e Q-peak, namely MeV. On t h e o t h e r hand, t h e I + (Kp) decay mode i s a b o u t 300 MeV.

s e e n t o peak n e a r 1250 MeV and i s narrower. The phase V. Chaloupka p r e s e n t e d p r e l i m i n a r y r e s u l t s of a n of t h e (KP) t o ( K : ~ ~ x ) 1 + a m p l i t u d e appears t o be A s c o l i - t y p e p a r t i a l wave a n a l y s i s of t h e ((ox)-system

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f a l l i n g from about 60' a t t h e (Km)-mass of 1.0 GeV i n t h e B-region f o r t h e r e a c t i o n s x p ^{-t T.} w p a t t o z e r o a t 1.5 GeV

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REFERENCES

[ I ] ASCOLI (G.) e t a l . , Phys. Rev. L e t t . 2 (1970) 962.

[ 2 ) ASCOLI (G.) e t a l . , Phys. Rev. L e t t . 26 (1971) 929.

[3] ASCOLI (G.) e t a l . , Phys. Rev. D7 (1973) 669.

[4 I ^HANSEN (J.D. 1, ^JONES (G.T. ) , ~ E R (G. ), RUDOLPH

( G . ) , Formalism and assumptions involved i n

t h e p a r t i a l wave a n a l y s i s of three-meson sys- tems, paper n0305.

[5 ] ANTIPOV (Y.M. ⁾ e t a l . , A1 ,A2 , A -production i n

<p --t x-x-T.+~ a t 25 and 40 % e ~ / c , paper n042.

[ 6 ] ANTIPOV (Y.M. ) e t a l . , The r e a c t i o n x-P --t

a t 25 and 40 GeV/c, paper n041.

[ 7 ] THOMPSON (G.) e t a l . , P a r t i a l wave a n a l y s i s of t h e (T.+T.+T.-) system i n t h e r e g i o n of t h e A3- meson , Purdue p r e p r i n t . Opposite t o

r e f . [ 5 3 t h e y f i n d a change i n phase f o r t h e (px) 2 S - s t a t e . I am g r a t e f u l t o Dr. L u b a t t j g i v i n g me t h i s p r e p i i n t .

[ 8 ] ANTIPOV (Y.M.) e t a l . , The decay channel A- ^-t qx- i n ~ t h e r e a c t i o n x-p --t ~ - x + + ? c - ~ a t 2 40 GeV/c, paper n043.

[ 9 ] BEMPORAD (c. ) e t a l . , P a r t i a l wave a n a l y s i s of t h e ( 3 x 1 - s t a t e s c o h e r e n t l y produced on nu- c l e i , paper n0215.

[ l o ] Aachen-Berlin-CERN-London-Vienna c o l l a b o r a t i o n , A p a r t i a l wave a n a l y s i s of t h e (K xfx-)

system, paper n0306.

[ l l ] CHALOUPKA f V . ), A n a l y s i s of t h g (wx)-system produced i n t h e r e a c t i o n x p + w x p ,

paper n0422.