https://doi.org/10.1140/epjc/s10052-021-09806-1
Regular Article - Theoretical Physics
Neutron-mirror neutron mixing and neutron stars
1
Dipartimento di Fisica e Chimica, Università di L’Aquila, 67100, Coppito, L’Aquila, Italy
2
INFN, Laboratori Nazionali del Gran Sasso, 67010, Assergi, L’Aquila, Italy
3
Consiglio Nazionale delle Ricerche, CNR-SPIN, 67100, Coppito, L’Aquila, Italy
a
zurab.berezhiani@lngs.infn.it
Received:
22
April
2021
Accepted:
28
September
2021
Published online:
26
November
2021
The oscillation of neutron n into mirror neutron 
, its mass degenerate partner from dark mirror sector, can gradually transform the neutron stars into the mixed stars consisting in part of mirror dark matter. In quark stars 
transitions are suppressed. We study the structure of mixed stars and derive the mass-radius scaling relations between the configurations of purely neutron star and maximally mixed star (MMS) containing equal amounts of ordinary and mirror components. In particular, we show that the MMS masses can be at most 
, where 
is a maximum mass of a pure neutron star allowed by a given equation of state. We evaluate transition rate in neutron stars, and show that various astrophysical limits on pulsar properties exclude the transition times in a wide range 
. For short transition times, 
year, the different mixed stars of the same mass can have different radii, depending on their age, which possibility can be tested by the NICER measurements. We also discuss subtleties related with the possible existence of mixed quark stars, and possible implications for the gravitational waves from the neutron star mergers and associated electromagnetic signals.
© The Author(s) 2021
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Funded by SCOAP3
