English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The big mass difference between the pion and rho meson possibly originatesfrom the spin-dependent nature of the interactions in the two states sincethese two states are similar except for spin. Both pi and rho arequark-antiquark systems which can be treated using the two-body Dirac equations(TBDE) of constraint dynamics. This relativistic approach for two-body systemhas the advantage over the non-relativistic treatment in the sense that thespin-dependent nature is automatically coming out from the formalism. Weemployed Dirac's relativistic constraint dynamics to describe quark-antiquarksystems. Within this formalism, the 16-component Dirac equation is reduced tothe 4-component 2nd-order differential equation and the radial part of thisequation is simply a Schroedinger-type equation with various terms calculatedfrom the basic radial potential. We used a modified Richardson potential forquark-antiquark systems which satisfies the conditions of confinement andasymptotic freedom. We obtained the wave functions for these two mesons whichare not singular at short distances. We also found that the cancellationbetween the Darwin and spin-spin interaction terms occurs in the pi mass butnot in the rho mass and this is the main source of the big difference in thetwo meson masses.

On the Mass Difference between pion and rho meson using a Relativistic Two-Body Model