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تسجيل مستخدم جديدThe chiral and angular momentum content of the $rho$-mesons in lattice QCD
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The variational method allows one to study the mixing of interpolators with different chiral transformation properties in the nonperturbatively determined physical state. It is then possible to define and calculate in a gauge-invariant manner the chiral as well as the partial wave content of the quark-antiquark component of a meson in the infrared, where mass is generated. Using a unitary transformation from the chiral basis to the $^{2S+1}L_J$ basis one may extract the partial wave content of a meson. We present results for the $rho$- and $rho$-mesons using a simulation with $N_f=2$ dynamical quarks, all for lattice spacings close to 0.15 fm. Our results indicate a strong chiral symmetry breaking in the $rho$ state and its simple $^3S_1$-wave composition in the infrared. For the $rho$-meson we find a small chiral symmetry breaking in the infrared as well as a leading contribution of the $^3D_1$ partial wave, which is contradictory to the quark model.
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The variational method allows one to study the mixing of interpolators with different chiral transformation properties in the non-perturbatively determined physical state. It is then possible to define and calculate in a gauge-invariant manner the ch
iral as well as the partial wave content of the quark-antiquark component of a meson in the infrared, where mass is generated. Using a unitary transformation from the chiral basis to the LSJ basis one may extract a partial wave content of a meson. We present results for the ground state of the rho-meson using quenched simulations as well as simulations with two dynamical quarks, all for lattice spacings close to 0.15 fm. We point out that these results indicate a simple 3S1-wave composition of the rho-meson in the infrared, like in the SU(6) flavor-spin quark model.
We identify the chiral and angular momentum content of the leading quark-antiquark Fock component for the $rho(770)$ and $rho(1450)$ mesons using a two-flavor lattice simulation with dynamical Overlap Dirac fermions. We extract this information from
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It is possible to define and calculate in a gauge-invariant manner the chiral as well as the partial wave content of the quark-antiquark Fock component of a meson in the infrared, where mass is generated. Using the variational method and a set of int
erpolators that span a complete chiral basis we extract in a lattice QCD Monte Carlo simulation with two dynamical light quarks the orbital angular momentum and spin content of the rho-meson. We obtain in the infrared a simple 3S1 component as a leading component of the rho-meson with a small admixture of the 3D1 partial wave, in agreement with the SU(6) flavor-spin symmetry.
We calculate the parameters describing elastic $I=1$, $P$-wave $pipi$ scattering using lattice QCD with $2+1$ flavors of clover fermions. Our calculation is performed with a pion mass of $m_pi approx 320::{rm MeV}$ and a lattice size of $Lapprox 3.6$
fm. We construct the two-point correlation matrices with both quark-antiquark and two-hadron interpolating fields using a combination of smeared forward, sequential and stochastic propagators. The spectra in all relevant irreducible representations for total momenta $|vec{P}| leq sqrt{3} frac{2pi}{L}$ are extracted with two alternative methods: a variational analysis as well as multi-exponential matrix fits. We perform an analysis using Luschers formalism for the energies below the inelastic thresholds, and investigate several phase shift models, including possible nonresonant contributions. We find that our data are well described by the minimal Breit-Wigner form, with no statistically significant nonresonant component. In determining the $rho$ resonance mass and coupling we compare two different approaches: fitting the individually extracted phase shifts versus fitting the $t$-matrix model directly to the energy spectrum. We find that both methods give consistent results, and at a pion mass of $am_{pi}=0.18295(36)_{stat}$ obtain $g_{rhopipi} = 5.69(13)_{stat}(16)_{sys}$, $am_rho = 0.4609(16)_{stat}(14)_{sys}$, and $am_{rho}/am_{N} = 0.7476(38)_{stat}(23)_{sys} $, where the first uncertainty is statistical and the second is the systematic uncertainty due to the choice of fit ranges.
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