Search for solar axions emitted in an M1 transition in 7Li* nuclei

Search for solar axions emitted in the M1-transition of 7Li* with Borexino CTF

“…therein). An attempt to detect such axions through resonant absorption in 7 Li nuclei target have been performed in [34,35].…”

7Li solar axions: preliminary results and feasibility studies

“…The first experimental work, searching for the 7 Li solar axions, gave the limit: m a < 32 keV [3]. Later it was improved to the value of 16 keV [5]. The limits from 7 Li are higher than those obtained considering 83 Kr (m a < 5.5 keV [6]) and 57 Fe (m a < 216 eV [7]).…”

“…[5]. While this improvement is modest, nevertheless it is important because it closes the existing window of possible axion masses between the previous limit of 16.0 keV and the 14.4 keV energy of the next potential source of quasimonochromatic solar axions from 57 Fe.…”

“…In the subsequent deexcitation process, γ's of 477.6 keV will be emitted (electron conversion coefficient is very low: 7.3 × 10 −7 [4]), and, therefore, the possible presence of such axions can be singled out by the presence of the characteristic peak in the energy distribution of a suitable detector placed close to or containing the 7 Li sample. The total number of resonant axion absorption processes in a 7 Li sample, containing N 7 number of 7 Li nuclei, has been calculated [3,5] by taking into account the current Solar Standard Model as:…”

Search for 14.4 keV solar axions emitted in the M1-transition of57Fe nuclei with CAST

“…, which means that axions can be emitted in magnetic nuclear transitions. Up to now, these monoenergetic solar axions have mostly been searched for by using the resonant axion absorption process in targets made of the same nuclides in a terrestrial laboratory [27][28][29][30][31][32][33], or via processes based on axionelectron interactions, like Compton conversion of axion to photon and the axioelectric effect [34,35].…”