6533b859fe1ef96bd12b7fd1
RESEARCH PRODUCT
Dispersive analysis of the γ*γ*→ππ process
Oleksandra DeinekaMarc VanderhaeghenIgor Danilkinsubject
PhysicsParticle physicsUnitarity010308 nuclear & particles physicsScatteringHadronStructure (category theory)01 natural sciencesHelicityPionAmplitudeDispersion relation0103 physical sciences010306 general physicsdescription
We present a dispersive analysis of the double-virtual photon-photon scattering to two pions up to 1.5 GeV. Through unitarity, this process is very sensitive to hadronic final-state interaction. For the $s$-wave, we use a coupled-channel $\ensuremath{\pi}\ensuremath{\pi}$, $K\overline{K}$ analysis which allows for a simultaneous description of both ${f}_{0}(500)$ and ${f}_{0}(980)$ resonances. For higher energies, ${f}_{2}(1270)$ shows up as a dominant structure which we approximate by a single-channel $\ensuremath{\pi}\ensuremath{\pi}$ rescattering in the $d$-wave. In the dispersive approach, the latter requires taking into account $t$- and $u$-channel vector-meson exchange left-hand cuts which exhibit an anomalouslike behavior for large spacelike virtualities. We show how to readily incorporate such behavior using a contour deformation. Besides, we devote special attention to kinematic constraints of helicity amplitudes and show their correlations explicitly.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2020-03-09 | Physical Review D |