Eur. Phys. J. A 17, 77-82 (2003)
DOI: 10.1140/epja/i2002-10147-0

A remark on the large difference between the glueball mass and in quenched QCD

N. Ishii¹ and H. Suganuma<sup>2

1</sup>  Radiation Laboratory, The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
²  Faculty of Science, Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro, Tokyo 152-8551, Japan

ishii@rarfaxp.riken.go.jp
suganuma@th.phys.titech.ac.jp

(Received: 18 November 2002 / Revised version: 16 January 2003 / Published online: 29 April 2003)

Abstract
The lattice QCD studies indicate that the critical temperature MeV of the deconfinement phase transition in quenched QCD is considerably smaller than the lowest-lying glueball mass MeV, i.e., . As a consequence of this large difference, the thermal excitation of the glueball in the confinement phase is strongly suppressed by the statistical factor even near . We consider its physical implication, and argue the abnormal feature of the deconfinement phase transition in quenched QCD from the statistical viewpoint. To appreciate this, we demonstrate a statistical argument of the QCD phase transition using the recent lattice QCD data. From the phenomenological relation between and the glueball mass, the deconfinement transition is found to take place in quenched QCD before a reasonable amount of glueballs is thermally excited. In this way, quenched QCD reveals a question "what is the trigger of the deconfinement phase transition ?"

PACS
12.38.Mh - Quark-gluon plasma.
12.38.Gc - Lattice QCD calculations.
12.39.Ba - Bag model.
12.39.Mk - Glueball and nonstandard multi-quark/gluon states.

© Società Italiana di Fisica, Springer-Verlag 2003