Heavy QCD axion at Belle II: Displaced and prompt signals

Emilie Bertholet, Sabyasachi Chakraborty, Vazha Loladze, Takemichi Okui, Abner Soffer, Kohsaku Tobioka

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


The QCD axion is a well-motivated addition to the standard model to solve the strong CP problem. If the axion acquires mass dominantly from a hidden sector, it can be as heavy as O(1) GeV, and the decay constant can be as low as O(100) GeV without running into the axion quality problem. We propose new search strategies for such heavy QCD axions at the Belle II experiment, where the axions are expected to be produced via B→Ka. We find that a subsequent decay a→3π with a displaced vertex leads to a unique signal with essentially no background, and that a dedicated search can explore the range O(1-10) TeV of decay-constant values. We also show that a→γγ can cover a significant portion of currently unexplored region of 150ma500 MeV.

Original languageEnglish
Article numberL071701
JournalPhysical Review D
Issue number7
StatePublished - 1 Apr 2022


FundersFunder number
Israel Ministry of Science
US-Israel Binational Science Fund
U.S. Department of EnergyDE-SC0010102
Japan Society for the Promotion of Science21H01086
Israel Science Foundation
Tel Aviv University


    Dive into the research topics of 'Heavy QCD axion at Belle II: Displaced and prompt signals'. Together they form a unique fingerprint.

    Cite this