by On 17 June, the XENON collaboration, which searches for excess nuclear recoils in the XENON1T detector, a one-tonne liquid-xenon time-projection chamber (TPC) located underground at Gran Sasso National Laboratory in Italy, reported an unexpected excess in electronic recoils at energies of a few keV, just above its detection threshold. The excess is incompatible with background expectation at the 3-sigma level. Among the possible interpretations of the excess are solar axions. Although the signal fits well the expectation from such signal, the axion parameters needed are strongly rejected by astrophysical observations. The excess can have a more mundane origin, like a tiny tritium contamination in the Xenon. In any case, it brings excitement to the field!
See a recent CERN Courier article on the XENON1T excess.
