Do neutrinos have mass, and how do we know?
A) No, because they are observed to move at lightspeed.
B) No, because we have observed that their paths remain straight as they pass through a magnetic field.
C) Yes, because we have observed them to move slower than lightspeed.
D) Yes, for both of the reasons listed in answers c and d.
E) Yes, because we have observed them to transmute from one of the three neutrino types to another.

Question

Quizplus · Accepted Answer

Neutrinos have mass because they can oscillate between different types (flavors), which requires them to have mass. This phenomenon is known as neutrino oscillation and has been observed in experiments.

Do Neutrinos Have Mass, and How Do We Know