NeutrinoWorld

NeutrinoWorld is an interactive game-like environment with a retro-aesthetic that is meant to simulate neutrino interactions with protons and neutrons. Neutrinos have no electric charge and almost no mass, and their interactions with matter are very feeble. Depending on their energy, neutrinos can pass through large amounts of matter, even planets and stars.  Neutrinos are undetectable, absolutely invisible unless they interact with a proton or neutron. When this happens, charged particles are produced.  High-energy charged particles in a transparent medium produce light, or photons, known as Cherenkov radiation. A neutron is a subatomic particle with no net electric charge and a mass slightly larger than that of the positively charged proton.
 
An important fundamental property of quantum systems conceptually conveyed in NeutrinoWorld is that a neutrino exists as a superposition of distinct states, the so-called neutrino flavours---electron, muon, and tau.  The relative makeup of each flavour varies as the neutrino travels, a process referred to as oscillation.  When the neutrino interacts with a proton or neutron, it must assume a single flavour identity.   In the simplest cases, the pattern of the light produced reveals the neutrino’s flavour. 

	muons (tracks) When a high-energy muon neutrino interacts with a proton or neutron, a muon is created.  The muon travels up to several kilometers and produces a cone of light that appears like the wake behind a boat. The Track shown is a powerful, 32 TeV muon neutrino event that was likely created by a distant powerful cosmic engine.
	electrons (cascades) When a high-energy electron neutrino interacts with a proton or neutron, an electron is created.  The electron reacts strongly with atoms so only travels a few meters, producing a burst of secondary particles that radiate outward. The Track shown is the second highest energy neutrino ever measured, 1100 TeV, “Ernie”, one of the few dozen astrophysical neutrinos that have been detected."
	tau (double bangs) Never seen before, a tau neutrino event would produce a high-energy cascade, then the particle shower radiates outward, while the tau travels from a few to hundreds of meters (depending on its energy), producing a cone of light.  The tau then decays, producing a second burst of particles that radiate outward.  The pattern is dumbbell-shaped.

NeutrinoWorld simulates these interactions, and allows players to learn the patterns by choosing the neutrino flavour at the time of impact with the proton or neutron. In previous installation,  NeutrinoWorld has been connected to the 8 foot^3 IceCube LED Display with interactions between the NeutrinoWorld and the Display synchronized with the activity of users in the installation space.