RESULTS FROM LENA COLLABORATION

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Submitted on 1 Jan 1982

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RESULTS FROM LENA COLLABORATION

R. Kraemer

To cite this version:

R. Kraemer. RESULTS FROM LENA COLLABORATION. Journal de Physique Colloques, 1982, 43 (C3), pp.C3-39-C3-39. �10.1051/jphyscol:1982304�. �jpa-00221857�

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JOURNAL DE PHYSIQUE

CoZZoque ~ 3 , suppZ&ment au n o 12, Tom3 43, dgcembre 1982 page C3-39

RESULTS FROM LENA COLLABORATION

R.W. Kraemer

Department o f Physics, Gar~egie-MeZZon University, Pittsburgh, PA 25223 U . S . A.

A . e'e- Hadronic Cross Section ( R ) . - The r a t i o R = a ( e + e - + hadrons)/o(e+e- + p

+

u-)

was measured with t h e LENA d e t e c t o r a t nORIS i n a scan between 7.40 and 7.48 GeV and between 8.67 and 9.43 GeV c e n t e r of mass energies. The t o t a l number of hadronic events was 4052 and t h e i n t e q r a t e d luminosity 1141 nh-l. Corrected f o r FED r a d i a t i v e e f f e c t s , R was found t o be constant with an average value of

R = 3.37 + 0.06 ( s t a t . ) ? 0.23 ( s y s t . )

No narrow resonance and no s t e p s were observed. The r e s u l t i s i n agreement with OCD.

Ye determined t h e upper l i m i t f o r reerhad/rtot o f a p o s s i b l e resonance t o be 0.30 keV (95% C . L . ) . From t h e t h e o r e t i c a l f i r s t order formula f o r a s we f i n d

a < 0.30 (60% C.L.).

S -

B. T(1S) Decay Topoloqy.

-

We have examined t h e Fox-Wolfram observable

f o r data from T ( 1 s ) and t h e continuum. We have compared t h e s p e c t r a f o r charged t r a c k s and f o r R i B t r a ~ c l u s t e r s . On t h e T ( l S ) , t h e d i s t r i b u t i o n i n rT1 s t r o n g l y f a v o r s t h e standard t h r e e gluon matrix element over t h r e e gluon phase space. In t h e continuum, t h e Ill d i s t r i b u t i o n i s c o n s i s t e n t with two quark fragmentation.

C . Gl uon Fragmentation. - The a x i s independent Fox-Wolfram moments, H I , were examined with t h e TDIq(lS d a t a . Isle compared moments f o r t h e standard gluon fragmentation model t o a model'in which t h e gluon fraqmentation t a k e s place v i a leading i s o s c a l a r s

( n , n l , w , @ ) . For t h e charged t r a c k d a t a no d i f f e r e n c e between models was obtained.

However, f o r t h e neutral p a r t i c l e d a t a , a d e f i n i t e preference f o r t h e leading i s o - s c a l a r model appears. A model with only i s o s c a l a r p a r t i c l e s i n gluon fraqmentation does not reproduce t h e observed energy and mu1 t i p 1 i c i t y d i s t r i b u t i o n s .

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1982304