tailieunhanh - Heavy diquark effective theory and supersymmetry of hadrons containing a single heavy quark

A new supersymmetry is proposed for hadrons containing a single heavy quark. This supersymmetry is based on a new approximation to those hadrons, which we would consider as a further step beyond the spectator light diquark model of baryons. The heavy diquark effective theory is constructed by the techniques introduced in a different context by Georgi and Wise [1] and by Carone [2]. This theory can be incorporated into a supersymmetric theory together with Heavy Quark Effective Theory, and leads to a common universal Isgur-Wise function for mesons and baryons. | Communications in Physics, Vol. 24, No. 1 (2014), pp. 35-43 HEAVY DIQUARK EFFECTIVE THEORY AND SUPERSYMMETRY OF HADRONS CONTAINING A SINGLE HEAVY QUARK NGUYEN AI VIET Information Technology Institute, Vietnam National University, Hanoi, Vietnam E-mail: naviet@ Received 25 December 2013 Accepted for publication 22 February 2014 Abstract. A new supersymmetry is proposed for hadrons containing a single heavy quark. This supersymmetry is based on a new approximation to those hadrons, which we would consider as a further step beyond the spectator light diquark model of baryons. The heavy diquark effective theory is constructed by the techniques introduced in a different context by Georgi and Wise [1] and by Carone [2]. This theory can be incorporated into a supersymmetric theory together with Heavy Quark Effective Theory, and leads to a common universal Isgur-Wise function for mesons and baryons. Keywords: heavy quark, diquark, heavy quark effective theory, supersymmetry. I. INTRODUCTION The hadrons containing one heavy quark turn out to have new symmetries, which are not manifest in QCD [3,4]. So their properties are constrained to a simpler description, the framework of the heavy quark effective theory [5–10] (HQET), where the mass of the heavy quark MQ is taken to infinity, with its velocity held fixed. In HQET, the heavy quark represents the kinematics of 1HQ-hadrons and is integrated out of dynamics as a very strong static color source or Wilson line, while the light degrees of freedom carry all the dynamics inside those hadrons. So the dynamics of 1HQ hadrons is independent of the mass and spin of the heavy quark. This leads to a SU (2Nf ) symmetry for each heavy quark velocity (Nf is the number of heavy flavors). Hence the long wavelength of light degrees of freedom in such hadrons are related by this symmetry, which gives relations between the weak form factors. These relations express the weak form factors in term of a single reduced form factor, .