English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We compute the next-to-leading, O(m alpha^5), contribution to the hyperfinesplitting in positronium within the framework of NRQED. When applied to theground state, our calculation reproduces known results, providing a furthertest of NRQED techniques. Besides providing a very simple method of calculationof the standard result, we also obtain new expressions for excited states ofpositronium with negligible additional effort. Our calculation requires thecomplete next-to-leading matching of the lowest-dimension NRQED four-fermicouplings, which we publish here for the first time.Comment: 24 pages, plain TeX, 6 figures included using eps

Nonrelativistic QED and next-to-leading hyperfine splitting in positronium