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Submitted on 1 Jan 1982
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SOME ASPECTS OF J/ψ AND ψ ’ HADRONIC DECAYSSLAC-LBL Mark II Collaboration
G. Trilling
To cite this version:
G. Trilling. SOME ASPECTS OF J/ψ AND
ψ’ HADRONIC DECAYSSLAC-LBL Mark II Collab-oration. Journal de Physique Colloques, 1982, 43 (C3), pp.C3-81-C3-81. �10.1051/jphyscol:1982316�.
�jpa-00221869�
JOURNAL DE PHYSIQUE
CoZZoque C3, suppldment au n o 1 2 , Tome 43, ddcembre 2982 page (23-81
SLAC-LBL Mark I1 Collaboration
Presented by G.H. T r i l l i n g
Department o f Physics, U n i v e r s i t y o f C a l i f o r n i a , Berkeley, C a l i f o r n i a 94720, U.S.A.
We r e p o r t new r e s u l t s on hadronic decays of J/q and Ijr' based on samples of about 10 t o t a l decays from each p a r e n t obtained with t h e Mark 6 I1 d e t e c t o r a t SPEAR.
We have reconstructed q ' exclusive hadronic f i n a l s t a t e s produced v i a 9 ' + 3
gluons + hadrons. To avoid confusion between no from such s t a t e s and
r
from t h e numerous Ijrf -, y + X + y+
hadrons modes, we have only accepted no events i n which d e t e c t i o n of both photons permitted unambiguous no reconstruction. We list various f i n a l s t a t e s X followed i n parentheses by t h e measured r a t i o s B ( @ ' + X)/B(J/V -, x ) :5p (0.10
+
0.024), ppnO (0.14+
0.06), K+~-n+n- (0.22+
0 . 0 8 ) ~ 2n+2rr-no (0.076 f 0.013),0 0
cun+R- (0.108
+
0 . 0 3 8 ) ~ 3n+3n-no (0.13 2 0 . 0 6 ) ~ K * ' ( ~ ~ o ) K ' (< 0 . 0 2 ) ~ p n (< 0 . 0 0 9 ) ~$rrT (< 0 . 0 1 5 ) ~ where upper l i m i t s r e p r e s e n t 90% C.L. I f 3-gluon s t a t e s from Ijrt decay hadronize analogously t o t h o s e from J/$ decay, one would expect t h e above r a t i o s t o be about equal t o t h a t f o r t h e d i l e p t o n f i n a l s t a t e ( 0 . 1 2 f 0 . 0 2 ) . This i s indeed t h e case with t h e notable exceptions of t h e K*K and pn f i n a l s t a t e s which seem highly suppressed i n q ' decay.
We have a l s o reconstructed many J/V exclusive decays i n t o baryon-antibaryon p a i r s with and without accompanying p a r t i c l e s . Branching r a t i o s f o r t h e unaccom- panied BE p a i r s i n u n i t s of a r e a s follows: pp (2.16f 0.16), Z A (1.58 f 0.20),
-0 0
-
c c ( 1 . 5 8 k 0 . 2 9 ) ~ Z+E- ( 1 . 1 4 f 0 . 2 1 ) , i Y - ~ + + (1.05+0.27), Z*+cWc ( 0 . 8 0 f o . 2 7 ) ~
cX-c)(+
(1.17+
0.37),c+cWc
(0.41+
0. l g ) , ?c*+ (0.38+
0.15). c* stands f o r C(1385) and t h e l a s t two e n t r i e s a l s o include t h e charge conjugate s t a t e s . The r e l a t i v e r a t e s f o r baryon charge-conjugate-baryon s t a t e s , from both t h e nucleon o c t e t and t h e lowest lying decimet, agree well with S U ( ~ ) expectations. However t h e S U ( ~ ) viola- t i n g &* occur with remarkably l a r g e branching r a t i o s , t h e suppression being only a f a c t o r of .U 3 below t h e corresponding S U ( ~ ) allowed r a t e s .Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1982316