https://doi.org/10.1140/epjc/s10052-022-10061-1
Regular Article - Experimental Physics
Probing the axion–nucleon coupling with the next generation of axion helioscopes
1
Dipartimento di Fisica e Astronomia ‘G. Galilei’, Università di Padova, Padua, Italy
2
Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Padua, Italy
3
Center for Astroparticles and High Energy Physics (CAPA), Universidad de Zaragoza, 50009, Zaragoza, Spain
4
Physical Sciences, Barry University, 11300 NE 2nd Ave., 33161, Miami Shores, FL, USA
5
Institut für theoretische Physik, Universität Heidelberg, Philosophenweg 16, 69120, Heidelberg, Germany
6
Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
7
Lawrence Livermore National Laboratory, 7000 East Avenue, 94551, Livermore, CA, USA
Received:
22
November
2021
Accepted:
25
January
2022
Published online:
8
February
2022
A finite axion–nucleon coupling, nearly unavoidable for QCD axions, leads to the production of axions via the thermal excitation and subsequent de-excitation of 
Fe isotopes in the sun. We revise the solar bound on this flux adopting the up to date emission rate, and investigate the sensitivity of the proposed International Axion Observatory IAXO and its intermediate stage BabyIAXO to detect these axions. We compare different realistic experimental options and discuss the model dependence of the signal. Already BabyIAXO has sensitivity far beyond previous solar axion searches via the nucleon coupling and IAXO can improve on this by more than an order of magnitude.
© The Author(s) 2022
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Funded by SCOAP3
