Ambiguous IceCube event may be caused by a tau neutrino

Avatar By Le Williams | 2 years ago

Physicists Matthew Kistler of Stanford and Ranjan Laha of Mainz University have analyzed the detection of various high-energy neutrinos events, with an objective to explain a singular mystery. In June 2014, the IceCube sensors detected a particle with extraordinarily high energy.

Calculations confirmed that the particle deposited 2.6 petaelectron-volts (PeV), which translates to 2.6 quadrillion electron-volts. By way of comparison, collisions between protons in the Large Hadron Collider (LHC) at CERN, the world’s largest particle accelerator, occur at an energy of just 13 trillion electron-volts.

“The track registered in June 2014 throws up all sorts of questions,” said Laha, pointing out that this is the maximum high-energy event recorded to date. “The foremost questions is what sort of neutrino would leave behind a track like this.” There are three types of neutrino: electrons, muons, and tau neutrinos.

Recent studies enabled the two physicists to base their investigations on the standard assumption that the track had been produced by a muon.

Following the collision with an atom nucleus, a muon neutrino would have been transformed into a muon and thus would have been captured by the optical sensors of the IceCube detector.

“However, we have demonstrated that this hypothesis is constrained,” explained Laha.

Alternatively, the two researchers propose a completely new and unconventional interpretation of the event. The track could be that of a high-energy tau lepton. To be registered by the detector with an energy of 2.6 PeV, the supposed tau neutrino would have to have had an initial energy of at least 50 PeV.

Laha and Kistler have concluded that the 2.6 PeV event was probably caused by a component of the neutrino spectrum previously unknown to astrophysicists. A certain continuity is usually to be expected when it comes to the events recorded by IceCube. However, the gap between the stated event with the highest energy captured to date and the other registered data is unusually large.

“We still don’t really know what caused the 2.6 PeV track. It is generally assumed to be a transiting muon. We show that it is also possible to be a transiting-tau particle,” concluded Laha. “We consider this event so significant that we believe it should be examined more closely. And we need more data to be able to discover more and decode this message sent us by the cosmos.”