Things that go bump in the sea

T. Sloan (Lancaster University)

• Neutrino interactions (>1020 eV)

• Axions (sadly Cotton-Mouton term)

• Primordial black holes

• Any other unexpected phenomenon.

Expected pulse shapes

Backgrounds give a train of osillations.

Limits from array using 4 fold coincidence of hydrophones (from Simon Bevan UCL Thesis)

Increase sensitivity - give up coincidence requirement

• Increases the solid angle coverage since showers detectable outside the plane of the array.

• More noise – ask for bigger pulses

Raw spectrum of peak amplitudes

APPLY CUTS

Final spectrum for 2 weeks of data.

Analyse all 245 days of data selecting triggers with peak pressureabove 0.4 Pa.

Examine all data (245 days)

• 81 events survive with peak pressure above 0.4 Pa.

• Each scanned visually to look for bipolar pulses.

• Most of them are multiple oscillations.

Conclusions

• 2 events (inverted probably background).

• No neutrinos (limit 5 orders of magnitude above W-B). Sensible limits need very large targets e.g. moon or polar ice cap (ANITA).

• No axions

• No primordial blackholes.

• No other unexpected phenomena.