Covariant spectator quark model description of the ${\gamma }^{\ast }\Lambda \to {\Sigma }^0$ transition

Abstract

We study the ${\gamma }^{\ast }\Lambda \to {\Sigma }^0$ transition form factors by applying the covariant spectator quark model. Using the parametrization for the baryon core wave functions as well as for the pion cloud dressing obtained in a previous work, we calculate the dependence on the momentum transfer squared, $Q^2$, of the electromagnetic transition form factors. The magnetic form factor is dominated by the valence quark contributions. The final result for the transition magnetic moment, a combination of the quark core and pion cloud effects, turns out to give a value very close to the data. The pion cloud contribution, although small, pulls the final result towards the experimental value The final result, ${\mu }_{\Lambda {\Sigma }^0}=-1.486{\mu }_N$, is about one and a half standard deviations from the central value in PDG, ${\mu }_{\Lambda {\Sigma }^0}=-1.61\pm 0.08{\mu }_N$. Thus, a modest improvement in the statistics of the experiment would permit the confirmation or rejection of the present result. It is also predicted that small but nonzero values for the electric form factor in the finite $Q^2$ region, as a consequence of the pion cloud dressing.

arXiv commentPublished version. Updated bibliography. 9 pages

References in corpus (37)

• Leading SU(3)-breaking corrections to the baryon magnetic moments in Chiral Perturbation Theory
• Baryon form factors in chiral perturbation theory
• Baryon magnetic moments in chiral perturbation theory
• Spin 1/2^+, spin 3/2^+ and transition magnetic moments of low lying and charmed baryons
• A pure S-wave covariant model for the nucleon
• D-state effects in the electromagnetic N-Delta transition
• Covariant equations for the three-body bound state
• Electromagnetic Form Factors of the SU(3) Octet Baryons in the semibosonized SU(3) Nambu-Jona-Lasinio Model
• A relativistic quark model for the Omega- electromagnetic form factors
• A Covariant model for the nucleon and the $\Delta$
• Octet baryon electromagnetic form factors in nuclear medium
• Valence quark contributions for the gamma N -> P11(1440) form factors
• Valence quark contribution for the gamma N -> Delta quadrupole transition extracted from lattice QCD
• Octet and Decuplet Baryon Magnetic Moments in the Chiral Quark Model
• Electromagnetic form factors of the Delta with D-waves
• A covariant model for the gamma N -> N(1535) transition at high momentum transfer
• Timelike gamma* N -> Delta form factors and Delta Dalitz decay
• Octet baryon electromagnetic form factors in a relativistic quark model
• Baryon Octet magnetic moments in $\chi$PT: More on the importance of the Decuplet
• Leading-order decuplet contributions to the baryon magnetic moments in Chiral Perturbation Theory
• Electromagnetic form factors of the baryon octet in the perturbative chiral quark model
• A model for the Delta(1600) resonance and gamma N -> Delta(1600) transition
• Phenomenological quark model for baryon magnetic moments and beta decay ratios ($G_A/G_V$)
• Covariant nucleon wave function with S, D, and P-state components
• Using baryon octet magnetic moments and masses to fix the pion cloud contribution
• Valence quark and meson cloud contributions for the gamma* Lambda -> Lambda* and gamma* Sigma0 -> Lambda* reactions
• Electric and magnetic form factors of strange baryons
• Fixed-axis polarization states: covariance and comparisons
• A simple relation between the gamma N -> N(1535) helicity amplitudes
• Magnetic Moments of the Octet Baryons in a Chiral Quark Potential Model
• The $\Omega$ and ${\Sigma }^0$-$\Lambda$ transition magnetic moments in QCD sum rules
• Pole Term and Gauge Invariance in Deep Inelastic Scattering
• Baryon Magnetic Moments in the 1/N_c Expansion with Flavor Symmetry Breaking
• The (Sigma^0 Lambda) Transition Magnetic Moment in Light Cone QCD Sum Rules
• Chiral QCD, General QCD Parameterization and Constituent Quark Models
• Magnetic moments of octet baryons and sea antiquark polarizations
• Transition magnetic moment of $\Lambda$ $\to$ ${\Sigma }^0$ in QCD sum rules

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• Electromagnetic transition form factors of baryons in the space-like momentum region
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• Semirelativistic approximation to the ${\gamma }^{\ast }N\to N(1520)$ and ${\gamma }^{\ast }N\to N(1535)$ transition form factors
• Hyperon elastic electromagnetic form factors in the space-like momentum region
• ${\gamma }^{\ast }N\to N(1710)$ transition at high momentum transfer
• $N^{\ast }$ Form Factors based on a Covariant Quark Model
• Electromagnetic form factors of the ${\Omega }^{-}$ baryon in the spacelike and timelike regions
• Meson cloud contributions to baryon axial form factors
• Covariant model for the Dalitz decay of the $N(1535)$ resonance
• A covariant model for the decuplet to octet Dalitz decays
• Octet baryon electromagnetic form factor double ratios $(G_E^{\ast }/G_M^{\ast })/(G_E/G_M)$ in a nuclear medium
• Space-like Electromagnetic Form Factors of Lambda- and Sigma-Baryons from Quark-Diquark Faddeev Equations
• Weak interaction axial form factors of the octet baryons in nuclear medium
• Meson cloud contributions to the Dalitz decays of decuplet to octet baryons
• Electroweak form factors of baryons in dense nuclear matter
• Analysis of ${\gamma }^{\ast }\Lambda \to {\Sigma }^0$ transition in QCD
• A covariant model for the ${\gamma }^{\ast }N\to N^{\ast }(1520)$ reaction
• A covariant model for the negative parity resonances of the nucleon
• A Relativistic Model for the Electromagnetic Structure of Baryons from the 3rd Resonance Region