Chiral perturbation theory of the hyperfine splitting in (muonic) hydrogen.
Saved in:
| Title: | Chiral perturbation theory of the hyperfine splitting in (muonic) hydrogen. |
|---|---|
| Authors: | Hagelstein, Franziska1,2,3 (AUTHOR) hagelste@uni-mainz.de, Lensky, Vadim1 (AUTHOR), Pascalutsa, Vladimir1 (AUTHOR) |
| Source: | European Physical Journal C -- Particles & Fields. Aug2023, Vol. 83 Issue 8, p1-18. 18p. |
| Subjects: | Chiral perturbation theory, Hyperfine coupling, Hydrogen, Factor structure, Polynomial chaos, Minkowski space |
| Abstract: | The ongoing experimental efforts to measure the hyperfine transition in muonic hydrogen prompt an accurate evaluation of the proton-structure effects. At the leading order in α , which is O (α 5) in the hyperfine splitting (hfs), these effects are usually evaluated in a data-driven fashion, using the empirical information on the proton electromagnetic form factors and spin structure functions. Here we perform a first calculation based on the baryon chiral perturbation theory (B χ PT). At leading orders it provides a prediction for the proton polarizability effects in hydrogen (H) and muonic hydrogen (μ H). We find large cancellations among the various contributions leading to, within the uncertainties, a zero polarizability effect at leading order in the B χ PT expansion. This result is in significant disagreement with the current data-driven evaluations. The small polarizability effect implies a smaller Zemach radius R Z , if one uses the well-known experimental 1S hfs in H or the 2S hfs in μ H. We, respectively, obtain R Z (H) = 1.010 (9) fm, R Z (μ H) = 1.040 (33) fm. The total proton-structure effect to the hfs at O (α 5) is then consistent with previous evaluations; the discrepancy in the polarizability is compensated by the smaller Zemach radius. Our recommended value for the 1S hfs in μ H is 182.640 (18) meV. [ABSTRACT FROM AUTHOR] |
| Copyright of European Physical Journal C -- Particles & Fields is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
|
Full text is not displayed to guests.
Login for full access.
|
|
Be the first to leave a comment!
