Publication : t99/139

Effects of HBT correlations on flow measurements

Dinh P.M. (CEA, DSM, SPhT (Service de Physique Théorique), F-91191 Gif-sur-Yvette, FRANCE)
Borghini N. (Laboratoire de Physique Théorique des Particules Elémentaires (LPTPE), Université Pierre et Marie Curie, 4 place Jussieu, F-75252 Paris cedex 05, FRANCE)
Ollitrault J.-Y. (CEA, DSM, SPhT (Service de Physique Théorique), F-91191 Gif-sur-Yvette, FRANCE)
Abstract:
The methods currently used to measure collective flow in nucleus--nucleus collisions assume that the only azimuthal correlations between particles are those arising from their correlation with the reaction plane. However, quantum HBT correlations also produce short range azimuthal correlations between identical particles. This creates apparent azimuthal anisotropies of a few percent when pions are used to estimate the direction of the reaction plane. These should not be misinterpreted as originating from collective flow. In particular, we show that the peculiar behaviour of the directed and elliptic flow of pions observed by NA49 at low $p_T$ can be entirely understood in terms of HBT correlations. Such correlations also produce apparent higher harmonics of the azimuthal distribution, of the order of 1\%, which should be looked for in the data.
Année de publication : 2000
Revue : Phys. Lett. B 477 51-58 (2000)
Preprint : arXiv:nucl-th/9912013
Langue : Anglais

 

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