Revisiting the bounds on hydrogen-antihydrogen oscillations from diffuse γ -ray surveys

Yuval Grossman, Wee Hao Ng, Shamayita Ray

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Surveys of diffuse γ rays in the interstellar medium (ISM) can be used to probe hydrogen-antihydrogen oscillations, by detecting the γ-ray emission from antihydrogen annihilation. A bound on the oscillation parameter δ was originally derived by Feinberg, Goldhaber, and Steigman (1978). In this paper, we revisit the original derivation by performing a more detailed analysis that (1) incorporates suppression effects from additional elastic and inelastic processes, (2) treats the ISM as a multiphase medium, and (3) utilizes more recent γ-ray data from the Fermi Large Area Telescope. We find that suppression from elastic scattering plays a more important role than previously thought, while the multiphase nature of the ISM affects how the γ-ray data should be utilized. We derive a more accurate bound on the oscillation period that is about an order of magnitude weaker than the older bound.

Original languageEnglish
Article number035020
JournalPhysical Review D
Issue number3
StatePublished - 1 Aug 2018
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2018 authors. Published by the American Physical Society.


We thank Lorenzo Calibbi, Shmuel Nussinov, and Chelsea Sharon for helpful discussions. The work of Y. G. is supported in part by the NSF Grant No. PHY1316222. The work of S. R. is supported by the Department of Science and Technology, Government of India through INSPIRE Faculty Fellowship (Grant No. IFA12-PH-41). S. R. would like to thank Y. G. for hosting the visit as a part of INSA-INSPIRE Faculty Fellowship, where a part of this work has been done.

FundersFunder number
National Science FoundationPHY1316222
Directorate for Mathematical and Physical Sciences1316222
Department of Science and Technology, Ministry of Science and Technology, IndiaIFA12-PH-41


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