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Learning about the chiral structure of the proton from the hyperfine splitting

Antonio Pineda
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Abstract

The complete analytical $O(m_l^3α^5/m_p^2\times (\log{m_π}, \logΔ, \log{m_l}))$ contribution to the Hyperfine splitting is given. It can explain about 2/3 of the difference between experiment and the pure QED prediction when setting the renormalization scale at the $ρ$ mass. The suppression of the polarizability piece with respect the Zemach one seems to be, to a large extent, a numerical accident. We give an estimate of the matching coefficient of the spin-dependent proton-lepton operator in heavy baryon effective theory.

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Antonio Pineda. 2003-08-19. Learning about the chiral structure of the proton from the hyperfine splitting. https://arxiv.org/abs/hep-ph/0308193

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