EXTRA SYMMETRIES IN THE EFFECTIVE THEORY OF HEAVY QUARKS

Extra symmetries are shown to exist in the effective theory of heavy q uarks when both quarks and antiquarks with the same velocity are inclu ded. These symmetries mix the quark with the antiquark sector and they resemble the axial type of symmetries. Together with the known flavor and spin symmetries they form a u(4) algebra when a single flavor is considered. It is shown that the full U(4) set of symmetries breaks sp ontaneously down to U(2) x U(2). The Goldstone modes corresponding to the spontaneously broken currents are identified and their relation to physical particles is discussed. Finally, the precise connection of t his theory with the fundamental QCD is derived and it is investigated under some approximations. Some physical processes where these extra s ymmetries may be relevant are pointed out.