Abstract

We explore kaon decays with missing energy carried away by a massless dark photon, γ¯, assumed to have flavor-changing dipole-type couplings to the d and s quarks. We consider in particular the neutral-kaon modes KLγγ¯ and KLπ0γγ¯ and their KS counterparts, as well as the charged-kaon channel K+π+γγ¯, each of which also has an ordinary photon, γ, in the final state. In addition, we look at KL,Sπ+π-γ¯ and K+π+π0γ¯. Interestingly, the same dsγ¯ interactions give rise to the flavor-changing two-body decays of hyperons with missing energy and are subject to model-independent constraints that can be inferred from the existing hyperon data. Taking this into account, we obtain branching fractions B(KLγγ¯) and B(KLπ0γγ¯) which can be as high as 10-3 and 10-6, respectively, one or both of which may be within the sensitivity reach of the KOTO experiment. Furthermore, we find that B(K+π+γγ¯) and B(K+π+π0γ¯) are allowed to be maximally of order 10-6 as well, which may be probed by NA62. Complementarily, the hyperon modes can have rates which are potentially accessible by BESIII. Thus, these ongoing experiments could soon be able to offer significant tests on the existence of the massless dark photon.

Details

Title
Kaon decays shedding light on massless dark photons
Author
Jhih-Ying, Su 1 ; Jusak, Tandean 2   VIAFID ORCID Logo 

 National Taiwan University, Department of Physics, Taipei, Taiwan (GRID:grid.19188.39) (ISNI:0000 0004 0546 0241) 
 National Taiwan University, Department of Physics, Taipei, Taiwan (GRID:grid.19188.39) (ISNI:0000 0004 0546 0241); National Center for Theoretical Sciences, Physics Division, Hsinchu, Taiwan (GRID:grid.38348.34) (ISNI:0000 0004 0532 0580) 
Publication year
2020
Publication date
Sep 2020
Publisher
Springer Nature B.V.
ISSN
14346044
e-ISSN
14346052
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2440323658
Copyright
© The Author(s) 2020. This work is published under https://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.