QCD compositeness as revealed in exclusive vector boson reactions through double-photon annihilation: e+e−→γγ⁎→γV0 and e+e−→γ⁎γ⁎→V0V0

Journal Article · Sun Jan 01 00:00:00 EST 2017 · Physics Letters B

DOI:https://doi.org/10.1016/j.physletb.2016.11.009· OSTI ID:1332769

Brodsky, Stanley J.; Lebed, Richard F.; Lyubovitskij, Valery E.

We study the exclusive double-photon annihilation processes, e⁺e^- →γγ* → γV⁰ and e⁺e^- γ*γ* V$$0\atop{a}$$V$$0\atop{b}$$, where the V$$0\atop{i}$$ is a neutral vector meson produced in the forward kinematical region: s>> -t and -t >> Λ$$2\atop{QCD}$$. We show how the differential cross sections $$dσ\atop{dt}$$, 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*→ $$q\bar{q}$$, these total cross sections σ(e⁺e^-→γV⁰)and σ(e⁺e^-→V$$0\atop{a}$$V$$0\atop{b}$$), 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^-→Z⁰V⁰and 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.

• Research Organization: SLAC National Accelerator Lab., Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: AC02-76SF00515
• OSTI ID: 1332769
• Alternate ID(s): OSTI ID: 1327481
• Report Number(s): SLAC-PUB-16809; S0370269316306700; PII: S0370269316306700
• Journal Information: Physics Letters B, Journal Name: Physics Letters B Vol. 764 Journal Issue: C; ISSN 0370-2693
• Publisher: Elsevier
• Country of Publication: Netherlands
• Language: English

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