T-odd momentum correlation in radiative β decay

Susan Gardner, Daheng He

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


The triple-product correlations observable in ordinary neutron or nuclear beta decay are all naively T violating and can connect, through an assumption of CPT invariance, to constraints on sources of CP violation beyond the Standard Model. They are also spin dependent. In this context the study of radiative beta decay opens a new possibility, in that a triple-product correlation can be constructed from momenta alone. Consequently its measurement would constrain new spin-independent sources of CP violation. We will describe these in light of the size of the triple momentum correlation in the decay rate arising from electromagnetic final-state interactions in the Standard Model. Our expression for the corresponding T-odd asymmetry is exact in (α) up to terms of recoil order, and we evaluate it numerically under various kinematic conditions. We consider the pattern of the asymmetries in nuclear β decays and show that the asymmetry can be suppressed in particular cases, facilitating searches for new sources of CP violation in such processes.

Original languageEnglish
Pages (from-to)71-78
Number of pages8
JournalHyperfine Interactions
Issue number1-3
StatePublished - Mar 2013

Bibliographical note

Funding Information:
We acknowledge partial support from the U.S. Department of Energy under contract no. DE-FG02-96ER40989.


  • Discrete symmetries
  • Neutrons
  • Weak decays

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Nuclear and High Energy Physics
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry


Dive into the research topics of 'T-odd momentum correlation in radiative β decay'. Together they form a unique fingerprint.

Cite this