In our universe, the down quark is about twice as heavy as the up quark, resulting in neutrons that are 0.1 percent heavier than protons.
The highest known magic number for neutrons alone is 126. Lead, with 82 protons and 126 neutrons, is thus "doubly magic" and the heaviest stable isotope in the periodic table.
Such facilities could search for other hypothesized phenomena such as the extremely rare decay of protons.
We cannot do anything about protons, they are buried in the nucleus, but we can add or subtract electrons.
When it had cooled further, these protons and neutrons were able to get together to form the nuclei of the lightest elements-hydrogen, helium and lithium.
Within an atom's nucleus, neutrons and protons jostle and change energy according to quantum mechanics, too.
If fusion was taking place, then neutrons flying through the plastic would cause protons within the material to recoil, leaving telltale tracks.
As protons or heavy nuclei, such as gold, are accelerated to nearly the speed of light, the quarks and gluons inside flatten into a pancakelike structure, a relativistic effect called Lorentz contraction.
Researchers re-injected particles late last month, but it was not until this weekend that bunches of protons were once again whizzing around the collider's entire circumference.
The process stripped protons and neutrons from the bismuth atoms, lowering the atoms' weight to that of gold atoms.
As the universe expanded and cooled, some of these particles merged to form neutrons and protons.
A bunch of protons smash into a fixed target, creating a horde of scattered mesons, which last for fractions of a second before decaying into neutrinos.
Both are hadron colliders: machines that smash protons into each other, or into their antimatter kin, at a smidgen below the speed of light in order to create shrapnel in the form of other particles.
Through some mysterious force, Trufa understood the miracle of her molecules, atoms, protons and electrons-the enormous energy she represented and the divine plan of which she was a part.
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