QCD compositeness as revealed in exclusive vector boson reactions through double-photon annihilation: e+e−→γγ⁎→γV0 and e+e−→γ⁎γ⁎→V0V0
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-θCM 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-θCM angular domains, scale as 1/s, and thus contribute to the leading-twist scaling behavior of the ratio Re+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:
- ElsevierCopyright Statement
- Country of Publication:
- Netherlands
- Language:
- English
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journal | June 2018 |
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