Antarctic Impulsive Transient Antenna

The ANITA-IV experiment in Antarctica before the start.

The Antarctic Impulsive Transient Antenna (also Antarctic Impulse Transient Antenna ) or ANITA experiment is a NASA- funded experiment to study ultra-high-energy cosmic neutrinos . For this purpose, the radio pulses generated by the interactions of the neutrinos with the Antarctic ice sheet are detected by radio antennas suspended from helium balloons. The altitude of the balloon is about 37 kilometers.

So far four experiments have been carried out. ANITA-I took off from McMurdo Station in Antarctica in the summer of 2006 and was supposed to travel around the continent with the circumpolar winds for about 35 days. ANITA-II, a modified instrument with 40 antennas, was launched from McMurdo Station in summer 2008–2009. ANITA-III, which was expected to increase sensitivity by a factor of 5-10, was launched in December 2014. ANITA-IV started in December 2016, with a lighter overall structure.

background

The neutrinos with energies in the order of magnitude of 10 ¹⁸ eV generate radio pulses in the Antarctic ice due to the Askaryan effect , which offers a huge detector volume of around 1.5 × 10 ⁶ km ^{3 of} ice. Since neutrinos are hardly distracted on their journey to earth, this may be the case. a direct conclusion about the source of the ultra-high-energy cosmic ray (UHECR ) is possible.

Possible evidence of BSM particles

The direction of movement of the original particles can be deduced from the angle of the incident radiation. At larger angles, i.e. zenith angles below the horizon of the antenna, it is assumed that the particles or their decay products have crossed the earth's interior over a certain distance. For distances longer than 5700 km, interpretations come into question in which decays into BSM particles ( Beyond Standard Model Particles ; elementary particles outside the Standard Model ) with subsequent decays into Standard Model particles are easier than interpretations that do not leave the Standard Model. Similar measurement results from the IceCube detector support the BSM interpretations.

On December 28, 2006 and December 20, 2014, events with zenith angles of well over 100 ° were measured. For these angles, the original particles or their decay products must have covered distances of up to 7210 km through the earth's interior.

Web pages

Impossible neutrino signals at scinexx.de

Individual evidence

↑ P. Miocinovic et al. a .: Tuning into UHE Neutrinos in Antarctica - The ANITA Experiment . In: 22nd Texas Symposium on Relativistic Astrophysics at Stanford University, 13-17 December 2004 , arxiv : astro-ph / 0503304
^ DB Fox et al. a .: The ANITA Anomalous Events as Signatures of a Beyond Standard Model Particle, and Supporting Observations from IceCube . arxiv : 1809.09615 [astro-ph]

[1] P. Miocinovic et al. a .: Tuning into UHE Neutrinos in Antarctica - The ANITA Experiment . In: 22nd Texas Symposium on Relativistic Astrophysics at Stanford University, 13-17 December 2004 , arxiv : astro-ph / 0503304

[2] DB Fox et al. a .: The ANITA Anomalous Events as Signatures of a Beyond Standard Model Particle, and Supporting Observations from IceCube . arxiv : 1809.09615 [astro-ph]