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Submitted on 1 Jan 1985
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CLOUDY BAG DESCRIPTION OF πd → πd, pp
A. Rinat
To cite this version:
A. Rinat. CLOUDY BAG DESCRIPTION OFπd → πd, pp. Journal de Physique Colloques, 1985, 46 (C2), pp.C2-475-C2-476. �10.1051/jphyscol:1985259�. �jpa-00224576�
JOURNAL DE PHYSIQUE
Colloque C2, supplement au n°2, Tome 46, fevrier 1985 page C2-*75
CLOUDY BAG DESCRIPTION OF ird -»• ird, pp A.S. Rinat
The Weizmann Institute of Science, 76100 Rehovot, Israel
Abstract : Calculations for itji in elastic pp scattering have been complet- ed. Changes with standard model predictions are small.
The first measurements of the vector polarization in TTd—JTTd / l / deviated much from standard model predictions /l/ and led to unorthodox explanations like the coupling of the A=2 system to dibaryons /3/.
Here we elaborate on an alternative suggestion namely that a cloudy bag model quark description of the excited A may lead to the observed it.. /A/• A phase shift analysis / s / pointed at small partial wave amplitudes which may produce (it^Jexp and those have been calculated to lowest order in I\/. Predictions differ only in the off-shell behaviour of t£N which is indeed surprisingly different for potential and bag models. It is clearly mandatory to follow how differences in t ^ f propagate in multiple scattering.
A calculation has been completed using a cloudy bag model description for the excited fl /6/. The driving terms for t4 are the interaction between a pion and a 3q bare A0, and the Chew-Low term. Changes in spin-averaged and polarization observables for "Vd-^ivd, pp never exceed 10-15% and in particular the relative minimum in it... (IT d—-> ltd, © *-70°, T^ ^ 250 MeV) /"]/ is not reproduced. (See figure).
Figure : Vector-polarization it., in "TTd-VTTd.
Dashed lines for standard model, drawn lines for cloudy bag model.
Résumé : Un calcul du paramètre itj^ dans la diffusion élastique pp a été fait. Ces prédictions diffèrent peu de celles du modèle standard.
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1985259
C2-476 JOURNAL DE PHYSIQUE
The mentioned changes are expected for observables computed for different parametri- zation~ of the standard model input. There is in particular no indication ofa signal due to a quark description of t' . We recall the Lennar-Jones fbrce between point atoms effectively replacing actual interactions in electron-clouds. Likewise we argue that at energies and momentum transfers under-discussion a standard description for the nn Vsystem suffices. /8/.
REFERENCES
1. BOLGER J. et al., Phys. Rev. Lett. 46 (1981), 167, (1982), 1667.
2. e.g. RINAT A.S. and STARKAND Y., Nucl. Phys. A397 (1983), 381.
3. LOCHER M.P. and SAINIO M.E., Phys. Lett. ~ ( 1 9 8 3 ) , 227.
4. RINAT A.S., Phys. Lett. 8126 (19831, 151.
5. ARVIEUX J., Phys. Lett. (1981), 99.
6. THEBERGE S. et al., ~ h ~ s x v . C22 (1980)~ 2838.
7. SMITH G.R. et al., Phys. Rev. 9 (1984), 2001.
8. RINAT A.S., submitted to Journal of Physics G.
