On the Mass Difference Between pi and rho Using a Relativistic Two-Body Model
- ORNL
- Inha University, Korea
- University of Tennessee (UT) Space Institute
The big mass difference between the pion(pi) and rho meson(rho) possibly originated from the spin-dependent nature of the interactions in the two states since these two states are similar except for spin. Both pi and rho are quark-antiquark systems which can be treated using the two-body Dirac equations (TBDE) of constraint dynamics. This relativistic approach for the two-body system has the advantage over the non-relativistic treatment in the sense that the spin-dependent nature is automatically coming out from the formalism. We employed Dirac's relativistic constraint dynamics to describe quark-antiquark systems. Within this formalism, the 16-component Dirac equation is reduced to the 4-component 2nd-order differential equation and the radial part of this equation is simply a Schroedinger-type equation with various terms calculated from the basic radial potential. We used a modified Richardson potential for quark-antiquark systems which satisfies the conditions of confinement and asymptotic freedom. We obtained the wave functions for these two mesons which are not singular at short distances. We also found that the cancellation between the Darwin and spin-spin interaction terms occurs in the pi mass but not in the rho mass, and this is the main source of the big difference in the two meson masses.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1133518
- Resource Relation:
- Conference: Fifth Asia-Pacific International Conference on Few-Body Systems in Physics, Seoul, South Korea, 20110822, 20110826
- Country of Publication:
- United States
- Language:
- English
Similar Records
Tests of two-body Dirac equation wave functions in the decays of quarkonium and positronium into two photons
Applications of two-body Dirac equations to the meson spectrum with three versus two covariant interactions, SU(3) mixing, and comparison to a quasipotential approach