Chiral symmetry breaking and the spin content of the rho and rho' mesons

Abstract

Using interpolators with different SU(2)_L \times SU(2)_R transformation properties we study the chiral symmetry and spin contents of the rho- and rho'-mesons in lattice simulations with dynamical quarks. A ratio of couplings of the $\qbarγ^iτq$ and $\qbarσ^{0i}τq$ interpolators to a given meson state at different resolution scales tells one about the degree of chiral symmetry breaking in the meson wave function at these scales. Using a Gaussian gauge invariant smearing of the quark fields in the interpolators, we are able to extract the chiral content of mesons up to the infrared resolution of ~1 fm. In the ground state rho meson the chiral symmetry is strongly broken with comparable contributions of both the (0,1) + (1,0) and (1/2,1/2)_b chiral representations with the former being the leading contribution. In contrast, in the rho' meson the degree of chiral symmetry breaking is manifestly smaller and the leading representation is (1/2,1/2)_b. Using a unitary transformation from the chiral basis to the {2S +1}L_J basis, we are able to define and measure the angular momentum content of mesons in the rest frame. This definition is different from the traditional one which uses parton distributions in the infinite momentum frame. The rho meson is practically a 3S_1 state with no obvious trace of a "spin crisis". The rho' meson has a sizeable contribution of the 3D_1 wave, which implies that the rho' meson cannot be considered as a pure radial excitation of the rho meson.

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References in corpus (8)

• The Deuteron Spin-dependent Structure Function g1d and its First Moment
• Coupled channel analysis of the rho meson decay in lattice QCD
• Restoration of chiral and $U(1{)}_A$ symmetries in excited hadrons
• Hadron Spectroscopy with Dynamical Chirally Improved Fermions
• Chiral symmetry and the string description of excited hadrons
• Angular momentum content of the rho-meson in lattice QCD
• Chiral symmetry, the angular content of the vector current in QED and QCD, and the holographic description of hadrons
• Effective chiral restoration in the rho'-meson in lattice QCD

Cited by in corpus (5)

• Towards two-body strong decay behavior of higher $\rho$ and ${\rho }_3$ mesons
• $\rho$ meson unpolarized generalized parton distributions with a light-front constituent quark model
• Chiral spin symmetry and hot/dense QCD
• A Hidden Local Symmetry Approach to Rho Meson Photoproduction
• Chiral symmetry breaking and the spin content of hadrons