## Abstract

We study the exclusive double-photon annihilation processes, e^{+}e^{−}→γγ^{⁎}→γV^{0} and e^{+}e^{−}→γ^{⁎}γ^{⁎}→V_{a} ^{0}V_{b} ^{0}, where the V_{i} ^{0} is a neutral vector meson produced in the forward kinematical region: s≫−t and −t≫Λ_{QCD} ^{2}. We show how the differential cross sections dσdt, as predicted by QCD, have additional falloff in the momentum transfer squared t due to the QCD compositeness of the hadrons, consistent with the leading-twist fixed-θ_{CM} scaling laws, both in terms of conventional Feynman diagrams and by using the AdS/QCD holographic model to obtain the results more transparently. However, even though they are exclusive channels and not associated with the conventional electron–positron annihilation process e^{+}e^{−}→γ^{⁎}→qq¯, these total cross sections σ(e^{+}e^{−}→γV^{0}) and σ(e^{+}e^{−}→V_{a} ^{0}V_{b} ^{0}), integrated over the dominant forward- and backward-θ_{CM} angular domains, scale as 1/s, and thus contribute to the leading-twist scaling behavior of the ratio R_{e+e− }. We generalize these results to exclusive double-electroweak vector-boson annihilation processes accompanied by the forward production of hadrons, such as e^{+}e^{−}→Z^{0}V^{0} and e^{+}e^{−}→W^{−}ρ^{+}. These results can also be applied to the exclusive production of exotic hadrons such as tetraquarks, where the cross-section scaling behavior can reveal their multiquark nature.

Original language | English (US) |
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Pages (from-to) | 174-179 |

Number of pages | 6 |

Journal | Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics |

Volume | 764 |

DOIs | |

State | Published - Jan 10 2017 |

## Keywords

- Electron–positron annihilation
- Electroweak bosons
- Hadron structure
- Quantum chromodynamics
- Tetraquarks
- Vector meson dominance

## ASJC Scopus subject areas

- Nuclear and High Energy Physics

## Fingerprint

Dive into the research topics of 'QCD compositeness as revealed in exclusive vector boson reactions through double-photon annihilation: e^{+}e

^{−}→ γγ

^{⁎}→ γV

^{0}and e

^{+}e

^{−}→ γ

^{⁎}γ

^{⁎}→ V

^{0}V

^{0}'. Together they form a unique fingerprint.