Azimuthal Anisotropy of $η$ and $π^{0}$ Mesons in Heavy-Ion Collisions at 2 AGeV

A. Taranenko; A. Kugler; R. Pleskac; P. Tlusty; V. Wagner; H. Lohner; R. W. Ostendorf; R. H. Siemssen; P. H. Vogt; H. W. Wilschut; R. Averbeck; S. Hlavac; R. Holzmann; A. Schubert; R. S. Simon; R. Stratmann; F. Wissmann; Y. Charbonnier; G. Martinez; Y. Schutz; J. Diaz; A. Marin; A. Doppenschmidt; M. Appenheimer; V. Hejny; V. Metag; R. Novotny; H. Stroher; J. Weiss; A. R. Wolf; M. Wolf; TAPS Collaboration

arXiv · nucl-ex/9903008

Azimuthal Anisotropy of $η$ and $π^{0}$ Mesons in Heavy-Ion Collisions at 2 AGeV

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Abstract

Azimuthal distributions of $η$ and $π^{0}$ mesons emitted at midrapidity in collisions of 1.9 AGeV $^{58}$Ni+$^{58}$Ni and 2 AGeV $^{40}$Ca+$^{nat}$Ca are studied as a function of the number of projectile-like spectator nucleons. The observed anisotropy corresponds to a negative elliptic flow signal for $η$ mesons, indicating a preferred emission perpendicular to the reaction plane. The effect is smallest in peripheral Ni+Ni collisions. In contrast, for $π^{0}$ mesons, elliptic flow is observed only in peripheral Ni+Ni collisions, changing from positive to negative sign with increasing pion transverse momentum.

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A. Taranenko, A. Kugler, R. Pleskac, P. Tlusty, V. Wagner, H. Lohner, R. W. Ostendorf, R. H. Siemssen, P. H. Vogt, H. W. Wilschut, R. Averbeck, S. Hlavac, R. Holzmann, A. Schubert, R. S. Simon, R. Stratmann, F. Wissmann, Y. Charbonnier, G. Martinez, Y. Schutz, J. Diaz, A. Marin, A. Doppenschmidt, M. Appenheimer, V. Hejny, V. Metag, R. Novotny, H. Stroher, J. Weiss, A. R. Wolf, M. Wolf, TAPS Collaboration. 1999-03-15. Azimuthal Anisotropy of $η$ and $π^{0}$ Mesons in Heavy-Ion Collisions at 2 AGeV. https://arxiv.org/abs/nucl-ex/9903008

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