Radiative resonance couplings in $\gamma \pi \to \pi \pi$

Abstract

Studies of the reaction $\gamma \pi \to \pi \pi$, in the context of the ongoing Primakoff program of the COMPASS experiment at CERN, give access to the radiative couplings of the $\rho (770)$ and ${\rho }_3(1690)$ resonances. We provide a vector-meson-dominance estimate of the respective radiative width of the ${\rho }_3$, ${\Gamma }_{{\rho }_3\to \pi \gamma }=48(18)$ keV, as well as its impact on the $F$-wave in $\gamma \pi \to \pi \pi$. For the $\rho (770)$, we establish the formalism necessary to extract its radiative coupling directly from the residue of the resonance pole by analytic continuation of the $\gamma \pi \to \pi \pi$ amplitude to the second Riemann sheet, without any reference to the vector-meson-dominance hypothesis.

arXiv comment7 pages, 3 figures; journal version

References in corpus (42)

• ππscattering
• Dispersion relation for hadronic light-by-light scattering: two-pion contributions
• The pion-pion scattering amplitude. IV: Improved analysis with once subtracted Roy-like equations up to 1100 MeV
• Roy equation analysis of pi pi scattering
• Precise measurement of the e+ e- to pi+ pi- (gamma) cross section with the Initial State Radiation method at BABAR
• Measurement of the ${\mathrm{e}}^{+}{\mathrm{e}}^{-}\to {\pi }^{+}{\pi }^{-}$ Cross Section between 600 and 900 MeV Using Initial State Radiation
• High-statistics measurement of the pion form factor in the rho-meson energy range with the CMD-2 detector
• Dispersion relation for hadronic light-by-light scattering: theoretical foundations
• Precise determination of the f0(600) and f0(980) pole parameters from a dispersive data analysis
• Towards a data-driven analysis of hadronic light-by-light scattering
• Update of the e^+e^-\toπ^+π^- cross section measured by SND detector in the energy region 400<\sqrt{s}<1000 MeV
• High-Statistics Study of the tau^- -> pi^- pi^0 nu_tau Decay
• Measurement of sigma(e+ e- -> pi+ pi-) from threshold to 0.85 GeV^2 using Initial State Radiation with the KLOE detector
• Precision measurement of $\sigma (e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\gamma )/\sigma (e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}\gamma )$ and determination of the ${\pi }^{+}{\pi }^{-}$ contribution to the muon anomaly with the KLOE detector
• Dispersive approach to hadronic light-by-light scattering
• The hadronic contributions to the anomalous magnetic moment of the muon
• Regge analysis of the pi pi scattering amplitude
• Rescattering effects in the hadronic-light-by-light contribution to the anomalous magnetic moment of the muon
• Dispersive analysis of omega --> 3pi and phi --> 3pi decays
• Dispersive analysis of the pion transition form factor
• omega --> pi0 gamma* and phi --> pi0 gamma* Transition form factors in dispersion theory
• Precision Determination of the Pion Form Factor and Calculation of the Muon $g-2$
• A new Parameterization for the Pion Vector Form Factor
• A New Measurement of the ${\pi }^0$ Radiative Decay Width
• Extracting the chiral anomaly from gamma pi --> pi pi
• Couplings of light I=0 scalar mesons to simple operators in the complex plane
• On the pi pi continuum in the nucleon form factors and the proton radius puzzle
• The $\pi \pi \to \pi {\gamma }^{\star }$ amplitude and the resonant $\rho \to \pi {\gamma }^{\star }$ transition from lattice QCD
• The resonant ${\pi }^{+}\gamma \to {\pi }^{+}{\pi }^0$ amplitude from Quantum Chromodynamics
• Neutral Pion Lifetime Measurements and the QCD Chiral Anomaly
• Resonance Production and $\pi \pi$ S-wave in ${\pi }^{-}+p\to {\pi }^{-}{\pi }^{-}{\pi }^{+}+p_{recoil}$ at 190 GeV/c
• The branching ratio $\omega \to {\pi }^{+}{\pi }^{-}$ revisited
• Electromagnetic corrections to gamma pi(+) -> pi(0) pi(+)
• Precise determination of the low-energy hadronic contribution to the muon $g-2$ from analyticity and unitarity: An improved analysis
• Two-pion low-energy contribution to the muon $g-2$ with improved precision from analyticity and unitarity
• Leading logarithms in the anomalous sector of two-flavour QCD
• The anomalous process gamma pi -> pi pi to two loops
• Chiral Anomaly and $\gamma 3\pi$
• A new determination of the $\gamma \pi \to \pi \pi$ anomalous amplitude via ${\pi }^{-}{e}^{-}\to {\pi }^{-}{e}^{-}{\pi }^0$ data
• Study of $\gamma \pi \to \pi \pi$ below 1 GeV using Integral Equation Approach
• Measurement of radiative widths of $a_2(1320)$ and ${\pi }_2(1670)$
• Radiative pi^pm gamma transitions of excited light-quark mesons in the covariant oscillator quark model

Cited by in corpus (43)

• The anomalous magnetic moment of the muon in the Standard Model
• Two-pion contribution to hadronic vacuum polarization
• Three-pion contribution to hadronic vacuum polarization
• Dispersion relation for hadronic light-by-light scattering: pion pole
• Pion-pole contribution to hadronic light-by-light scattering in the anomalous magnetic moment of the muon
• The anomalous magnetic moment of the muon in the Standard Model: an update
• Precision tests of fundamental physics with $\eta$ and ${\eta }^{\prime }$ mesons
• Kaon electromagnetic form factors in dispersion theory
• On the transition form factors of the axial-vector resonance $f_1(1285)$ and its decay into $e^{+}{e}^{-}$
• A dispersive estimate of scalar contributions to hadronic light-by-light scattering
• Hadronic vacuum polarization and vector-meson resonance parameters from $e^{+}{e}^{-}\to {\pi }^0\gamma$
• Asymptotic behavior of meson transition form factors
• Isospin-breaking effects in the two-pion contribution to hadronic vacuum polarization
• Dispersion relations for ${\gamma }^{\ast }{\gamma }^{\ast }\to \pi \pi$: helicity amplitudes, subtractions, and anomalous thresholds
• The $\pi \gamma \to \pi \pi$ transition and the $\rho$ radiative decay width from lattice QCD
• Nucleon matrix elements of the antisymmetric quark tensor
• Two-loop analysis of the pion-mass dependence of the $\rho$ meson
• Axial-vector transition form factors and $e^{+}{e}^{-}\to f_1{\pi }^{+}{\pi }^{-}$
• A phenomenological estimate of isospin breaking in hadronic vacuum polarization
• Isospin-breaking effects in the three-pion contribution to hadronic vacuum polarization
• The $\gamma \pi \to \pi \pi$ anomaly from lattice QCD and dispersion relations
• Quark-mass dependence in $\omega \to 3\pi$ decays
• Nucleon resonance parameters from Roy-Steiner equations
• What can we learn about light-meson interactions at electron-positron colliders?
• Dispersion relation for hadronic light-by-light scattering: $\eta$ and ${\eta }^{\prime }$ poles
• Dispersion relations for the hadronic VVA correlator
• On the scalar $\pi K$ form factor beyond the elastic region
• Width effects of broad new resonances in loop observables and application to $(g-2{)}_{\mu }$
• Dispersive analysis of the Primakoff reaction $\gamma K\to K\pi$
• Analysis of rescattering effects in $3\pi$ final states
• The semileptonic decays ${\eta }^{(\prime )}\to {\pi }^0{\ell }^{+}{\ell }^{-}$ and ${\eta }^{\prime }\to \eta {\ell }^{+}{\ell }^{-}$ in the standard model
• From pole parameters to line shapes and branching ratios
• Improved Standard-Model prediction for $K_L\to {\ell }^{+}{\ell }^{-}$
• Radiative corrections and Monte Carlo tools for low-energy hadronic cross sections in $e^{+}{e}^{-}$ collisions
• Rho-pion transition form factors in the $k_T$ factorization formulism revisited
• A Simple Parametrisation of the Pion Form Factor
• Polarizabilities from kaon Compton scattering
• Correlations of $C$ and $CP$ violation in $\eta \to {\pi }^0{\ell }^{+}{\ell }^{-}$ and ${\eta }^{\prime }\to \eta {\ell }^{+}{\ell }^{-}$
• Extracting the chiral anomaly from $e^{+}{e}^{-}\to 3\pi$
• Advanced parametrisations for hadronic form factors
• Dispersive determination of resonances from $\pi \pi$ scattering data
• Precision dispersive approaches versus unitarized Chiral Perturbation Theory for the lightest scalar resonances $\sigma /f_0(500)$ and $\kappa /K_0^{\ast }(700)$
• Dispersive Analysis of $D$- and $B$-Meson Form Factors with Chiral and Heavy-Quark Constraints