electron
A stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids.
Electrons belong to a class of particles called leptons.
physics
elementary particle
Another term for fundamental particle. "Fundamental particle" is preferable – there is nothing elementary about the complex interactions of subatomic particles.
event
An "event" is what happens after a collision: particles decay, form tracks and are detected.
See collision or event?.
femtobarn
A unit of area, equal to 10−43 square metres. See barn and inverse femtobarn.
"Femto" means a factor of 10-15, a thousandth of a millionth of a millionth. So a femtobarn is a barn (10-28 square metres) multiplied by 10-15, which equals 10-43 square metres.
When writing pages for the general public, always give an approximate number of collisions as well as the figure in inverse femtobarns.
fermion
A subatomic particle, such as a nucleon, which has half-integral spin and follows a statistical description given by Fermi and Dirac.
fundamental particle
Preferable to "elementary particle". There is nothing elementary about the complex interactions of subatomic particles.
g (lower case)
Denotes gravity in mathematical notation.
Specifically, g is the acceleration due to the local gravitational field – the force exerted by the Earth on a sky diver in free fall, for example.
The sky diver experienced a force of 5 g. (not "5 g's")
g is measured in metres per second per second (m/s2) and has a value of 9.81 m/s2 on Earth.
Not to be confused with G.
G (upper case)
Denotes the gravitational constant in mathematical notation.
G is the constant term in Newton's law of universal gravitation, which states: "The attractive force (F) between two bodies is proportional to the product of their masses (m1 and m2), and inversely proportional to the square of the distance (r) between them."
GEM detector
The Gas Electron Multiplier (GEM) is a gaseous-ionisation detector – a type of detector used in nuclear physics, particle physics and radiation detection.
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