Two-photon decays of hadronic molecules

Abstract

In many calculations of the two--photon decay of hadronic molecules, the decay matrix element is estimated using the wave function at the origin prescription, in analogy to the two-photon decay of parapositronium. We question the applicability of this procedure to the two-photon decay of hadronic molecules for it introduces an uncontrolled model dependence into the calculation. As an alternative approach, we propose an explicit evaluation of the hadron loop. For shallow bound states, this can be done as an expansion in powers of the range of the molecule binding force. In the leading order one gets the well-known point-like limit answer. We estimate, in a self-consistent and gauge invariant way, the leading range corrections for the two-photon decay width of weakly bound hadronic molecules emerging from kaon loops. We find them to be small. The role of possible short-ranged operators and of the width of the scalars remains to be investigated.

LaTeX2e, 26 pages, new figure and additional appendix added, version to appear in Phys.Rev.D

References in corpus (26)

• The Cosmological Parameters 2006
• Big-Bang nucleosynthesis (Particle Data Group mini-review)
• The New Heavy Mesons: A Status Report
• Evidence that the a0(980) and f0(980) are not elementary particles
• Scalar Mesons in $\varphi$ Radiative Decay: their implications for spectroscopy and for studies of CP-violation at $\varphi$ factories
• Light scalars as tetraquarks or two-meson states from large Nc and unitarized Chiral Perturbation Theory
• Two-Photon Decays of Mesons in a Relativistic Quark Model
• High statistics study of f_0(980) resonance in gamma gamma --> pi^+ pi^- production
• Flatte-like distributions and the a_0(980)/f_0(980) mesons
• Theoretical Study of the γγ-->meson-meson Reaction
• Gauge-invariant approach to meson photoproduction including the final-state interaction
• The radiative decay phi - gamma pi pi in a coupled channel model and the structure of f0(980)
• The radiative decays $\varphi \to \gamma a_0/f_0$ in the molecular model for the scalar mesons
• Gauging of equations method. I. Electromagnetic currents of three distinguishable particles
• Insights on scalar mesons from their radiative decays
• Lifetime of Kaonium
• Ordinary and Extraordinary Hadrons
• Gauge invariance in two-particle scattering
• $s\bar{s}$ dominance of the $f_0$(980) meson
• Towards a model independent determination of the phi -> f_0 - gamma coupling
• Shape of the $f_0(980)$ in $\gamma \gamma \to {\pi }^{+}{\pi }^{-}$
• Can one extract the pi-neutron scattering length from pi-deuteron scattering?
• Towards an understanding of the light scalar mesons
• Glueballs, Hybrids, Pentaquarks : Introduction to Hadron Spectroscopy and Review of Selected Topics
• Positronium Decay : Gauge Invariance and Analyticity
• Calculation of the two-photon decay width of the f_0(980) scalar meson

Cited by in corpus (63)

• Hadronic molecules
• The $XYZ$ states: experimental and theoretical status and perspectives
• Glueballs, Hybrids, Multiquarks. Experimental facts versus QCD inspired concepts
• From controversy to precision on the sigma meson: a review on the status of the non-ordinary $f_0(500)$ resonance
• Physics with the KLOE-2 experiment at the upgraded DA$\varphi$NE
• Chiral perturbation theory for heavy hadrons and chiral effective field theory for heavy hadronic molecules
• Strong and radiative decays of the Ds0*(2317) meson in the DK-molecule picture
• X(3872) as a hadronic molecule and its decays to charmonium states and pions
• Evidence that the Y(4660) is a f_0(980)psi' bound state
• Comprehensive Amplitude Analysis of $\gamma \gamma \to {\pi }^{+}{\pi }^{-},{\pi }^0{\pi }^0$ and $\overline{K}K$ below 1.5 GeV
• Confirming the molecular nature of the $Z_b(10610)$ and the $Z_b(10650)$
• Subleading contributions to the width of the D_{s0}*(2317)
• Couplings of light I=0 scalar mesons to simple operators in the complex plane
• Light meson mass dependence of the positive parity heavy-strange mesons
• Observation of a new narrow axial-vector meson $a_1(1420)$
• Strong and radiative decays of the $D_{s0}^{\ast }(2317)$ and $D_{s1}(2460)$
• Effective Lifetimes of $B_s$ Decays and their Constraints on the $B_s^0$-${\bar{B}}_s^0$ Mixing Parameters
• Anatomy of $B_{s,d}^0\to J/\psi f_0(980)$
• Ds0*(2317) and Ds1(2460) mesons in two-body B-meson decays
• The $X(3872)\to J/\psi \gamma$ decay in the $D{\bar{D}}^{\ast }$ molecular picture
• Investigation of a0-f0 mixing
• Two photon couplings of the lightest isoscalars from BELLE data
• Amplitude Analysis of High Statistics Results on $\gamma \gamma \to {\pi }^{+}{\pi }^{-}$ and the Two Photon Width of Isoscalar States
• Improved dispersion relations for γγ\to π^0π^0
• Molecular structure of the Bs0*(5725) and Bs1(5778) bottom-strange mesons
• Detecting the long-distance structure of the X(3872)
• f0(980) meson as a K bar K molecule in a phenomenological Lagrangian approach
• The mass spectra and decay properties of dimesonic states, using the Hellmann potential
• Strong and radiative decays of the scalars f0(980) and a0(980) in a hadronic molecule approach
• Two photons into π^0π^0
• Hadronic Loops versus Factorization in EFT calculations of $X(3872)\to {\chi }_{cJ}{\pi }^0$
• Gluonium nature of the sigma/f_0(600) from its coupling to KK
• Generalization of Weinberg's Compositeness Relations
• A Dispersive Analysis on the $f_0(600)$ and $f_0(980)$ Resonances in $\gamma \gamma \to {\pi }^{+}{\pi }^{-},{\pi }^0{\pi }^0$ Processes
• Scalar mesons and the fragmented glueball
• Update on strong and radiative decays of the $D_{s0}^{\ast }(2317)$ and $D_{s1}(2460)$ and their bottom cousins
• On the two-photon decay width of the sigma meson
• Weak decays of heavy hadron molecules involving the f0(980)
• Two-photon decay of heavy hadron molecules
• The role of the next-to-leading order triangle-shaped diagram in two-body hadronic decays
• Radiative decays with light scalar mesons and singlet-octet mixing in ChPT
• Two-photon decay of a light scalar quark-antiquark state
• Remarks on non-perturbative three--body dynamics and its application to the $KK\bar{K}$ system
• How and when can one identify hadronic molecules in the baryon spectrum
• 2γ-decays of scalar mesons (σ(600), f_0(980) and a_0(980)) in the Nambu-Jona-Lasinio model
• Comment on "Once more about the KK molecule approach to the light scalars"
• Do near-threshold molecular states mix with neighbouring $\bar{Q}Q$ states?
• Mass spectra of dimesonic states in light flavour sector
• Photoproduction and mixing effects of scalar a0 and f0 mesons
• Radiative decays of scalar mesons σ(600), f_0(980) and a_0(980) in the local Nambu-Jona-Lasinio model
• Two- and three-body structure of the Y(4660)
• Mass spectra of meson molecular states for heavy and light sectors
• Exclusive photon-fusion production of even-spin resonances and exotic QED atoms in high-energy hadron collisions
• KKbar molecules with momentum-dependent interactions
• Light-by-light forward scattering sum rules for charmonium states
• Illuminating hadron structure by scattering light on light
• Amplitude Analysis for Mesons and Baryons: Tools and Technology
• Dynamical generation of hadronic resonances
• Hadron physics with KLOE-2
• The effect of isospin violation on scalar meson production
• Gauge invariant formulation of 3$\gamma$ decay of particle-antiparticle bound states
• Radiative decays of hadronic molecules: From confusion to inspiration
• Exotic open and hidden charm states