The group velocity vg of the wave packet associated with the electron of rest mass
The rest mass
M of the body differs from the mass m of its substance due to the contribution from the field energies and energy of internal motion.
55) "The mass that a particle has when at rest is sometimes called its rest mass
l = h / mc = , that's why this kind of photon must have zero rest mass
e is the elementary charge, the electron rest mass
, and c the speed of light in vacuum.
Neutrinos were long believed to have zero rest mass
, meaning they should always travel at the speed of light, like photons.
The missing energy would amount to about 1 million electron volts, which is twice the rest mass
of an electron, and would be a telltale signature of the mirror universe, Gninenko asserts.
According to Ue-Li Pen and Abraham Loeb (Harvard-Smithsonian Center for Astrophysics) and Neil Turok (Cambridge University), in certain circumstances a neutron star - a 20-kilometer-wide ball of pure nuclear matter - could spontaneously convert its entire rest mass
into 1054 ergs of radiant energy in 11/41000 second.
If you had enough rest mass
to accelerate the particles to meet the Gott condition, you would close the universe," Farhi says.
Fourth, additional laboratory indications that ordinary neutrinos have a bit of rest mass
A neutrino with a magnetic moment, and one capable of changing from one kind to another, would also have to have a small rest mass
4 that the particle having a nonzero rest mass
cannot go before the light when moving in the same direction in any IRF.
That is, they constitute one possible kind of sterile neutrino, which may have to be invoked to fit simultaneously all the different 1998 measurements and hints of neutrino rest mass
that are coming to us from laboratory experiments, observations of solar neutrinos, and anomalies in the numbers of neutrinos produced when cosmic rays hit the Earth's atmosphere.
A further question is whether neutrinos have a very small rest mass
Following the procedure by Oppenheimer and Volkoff , the matter is considered to consist of particles with rest mass