physics

g (lower case)

coluanai — Thu, 01 Dec 2011 09:40:18 +0000

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.

muon

coluanai — Thu, 01 Dec 2011 13:29:28 +0000

An unstable subatomic particle of the same class as an electron (a lepton), but with a mass around 200 times greater. Muons make up much of the cosmic radiation reaching the Earth’s surface.

quark

coluanai — Thu, 01 Dec 2011 14:44:16 +0000

Any of a number of subatomic particles carrying a fractional electric charge, postulated as building blocks of the hadrons. Quarks have not been directly observed but theoretical predictions based on their existence have been confirmed experimentally.

Quarks have the different states up, down, top, bottom, charm and strange. Use a space after the state:

Of all the quarks I have studied, I find the up quark the most intriguing.

Unless they are used as compound adjectives:

Synchrocyclotron

coluanai — Wed, 01 Aug 2012 09:34:26 +0000

Capital "S" when referring to CERN's first particle accelerator. Otherwise, lower case.

A synchrocyclotron is a type of cyclotron in which the frequency of the driving radiofrequency-electric-field is varied to compensate for relativistic effects as particle velocity approaches the speed of light. This is in contrast to the classical cyclotron, where this frequency is constant.

G (upper case)

coluanai — Thu, 01 Dec 2011 09:46:40 +0000

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."

lepton

coluanai — Thu, 01 Dec 2011 13:30:48 +0000

Adjective: leptonic

A subatomic particle that does not take part in the strong interaction.

Examples include the electron, muon and neutrino.

event

coluanai — Thu, 01 Dec 2011 15:17:20 +0000

An "event" is what happens after a collision: particles decay, form tracks and are detected.

See collision or event?.

duoplasmatron

coluanai — Wed, 01 Aug 2012 16:12:09 +0000

Another great physics word.

A duoplasmatron is a type of ion source. It operates as follows: a cathode filament emits electrons into a vacuum chamber. A gas, such as argon, is introduced in very small quantities into the chamber, where it becomes charged or ionised through interactions with the free electrons from the cathode, forming a plasma. The plasma is then accelerated through a series of at least two highly charged grids, and becomes an ion beam, moving at fairly high speed from the aperture of the device.

particles

coluanai — Thu, 01 Dec 2011 10:50:12 +0000

Always spell out the name of the particle – do not use the mathematical symbol in text.

The mathematical symbols may be used in diagrams only when they are spelled out in full in the accompanying caption. See graphs and charts.

electron

coluanai — Thu, 01 Dec 2011 13:33:46 +0000

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.

luminosity

coluanai — Thu, 01 Dec 2011 16:20:36 +0000

The number of particles per unit area per time, multiplied by the opacity of the target (its impenetrability) to electromagnetic radiation.

Luminosity is measured in barns per second: b^-1s^-1

Luminosity is an important measure of the performance of a particle accelerator.

dark matter

coluanai — Tue, 14 Aug 2012 09:35:28 +0000

lower case

kaon

coluanai — Thu, 01 Dec 2011 11:02:00 +0000

Not "K-meson"

neutrino

coluanai — Thu, 01 Dec 2011 13:38:59 +0000

Plural: neutrinos.

A neutral subatomic particle with a mass close to zero and half-integral spin, which rarely reacts with normal matter. Three kinds of neutrinos are known, associated with the electron, muon, and tau particles.

barn

coluanai — Thu, 01 Dec 2011 16:27:38 +0000

Symbol b.

A unit of area. A barn is 10⁻²⁸ m² (100 fm²), about the cross-sectional area of a uranium nucleus.

A barn expresses the cross-section of any scattering process, which relates to the probability of interaction between small particles.

Sample size at CERN is often expressed in femtobarns and luminosity is expressed in inverse femtobarns.