Eur. Phys. J. A (2006) 27: 225-230
https://doi.org/10.1140/epja/i2005-10251-7

Hadron Physics

Casimir scaling, glueballs, and hybrid gluelumps

¹ Groupe de Physique Nucléaire Théorique, Université de Mons-Hainaut, Académie universitaire Wallonie-Bruxelles, Place du Parc 20, BE-7000, Mons, Belgium
² CWI, P.O. Box 94079, 1090, Amsterdam, The Netherlands

^* e-mail: claude.semay@umh.ac.be

Received: 17 November 2005
Accepted: 14 February 2006
Published online: 1 March 2006

Abstract

Assuming that the Casimir scaling hypothesis is well verified in QCD, masses of glueballs and hybrid gluelumps (gluon attached to a point-like c¯ pair) are computed within the framework of the rotating string formalism. In our model, two gluons are attached by an adjoint string in a glueball, while the gluon and the colour octet c¯ pair are attached by two fundamental strings in a hybrid gluelump. Masses for such exotic hadrons are computed with very few free parameters. These predictions can serve as a guide for experimental searches. In particular, the ground-state glueballs lie on a Regge trajectory and the lightest 2⁺⁺ state has a mass compatible with some experimental candidates.