Eur. Phys. J. A (2007) 31: 645-648
https://doi.org/10.1140/epja/i2006-10296-0

QNP 2006

The E687 cryptoexotic vector meson candidate

¹ Centro Studi e Ricerche Enrico Fermi, Roma, Italy
² Laboratori Nazionali di Frascati, INFN, Frascati, Italy

^* e-mail: simone.pacetti@lnf.infn.it

Received: 22 December 2006
Accepted: 1 January 2007
Published online: 23 March 2007

Abstract

A new study of the dip observed at 1.9GeV by the Fermilab experiment E687 in diffractive photoproduction of 3π ⁺3π ^- is presented. The E687 and the BABAR data on the annihilation cross-section σ(e ⁺ e ^-→3π ⁺3π ^-), obtained with initial-state radiation, are fitted all together. The fit function is based on a simple mixing mechanism that explains the manifestation of a resonance as a dip. Possible interpretations in terms of hybrids and tetraquark states are considered.