Warped Passages - Lisa Randall [226]
compactified A compactified space is one that is rolled-up into a finite size.
Compton scattering The scattering of a photon off an electron.
cosmological constant The value of a constant background energy density that isn’t carried by matter.
cosmology The science of the evolution of the universe.
coupling constant The number that determines interaction strength.
curvature A quantity that describes bending or curving of an object, space, or spacetime.
D-brane A brane in string theory on which open strings end.
dark energy The measured vacuum energy in the universe that constitutes about 70% of the universe’s energy but is not carried by any form of matter.
dark matter The nonluminous matter that carries about 25% of the energy in the universe.
de Sitter space Spacetime with constant positive curvature.
deep inelastic scattering The experiment that discovered quarks by scattering electrons off protons and neutrons.
desert hypothesis The assumption that there are no particles, aside from those included in the Standard Model, that can be produced at energies below the unification energy.
dimension An independent direction in space or time.
dimensionality The number of quantities required to uniquely pin down a point.
dimensionality of a brane The number of dimensions in which brane-bound particles are permitted to travel.
down quark One of the elementary quarks that compose the proton and the neutron.
dual theories Two equivalent descriptions of a single theory that might be superficially quite different.
effective field theory A quantum field theory defined at a particular energy that describes those particles and forces relevant to the energies to which it applies.
effective theory A theory describing those elements and forces that are in principle observable at the distance or energy scales over which it applies.
Einstein’s equations The equations of general relativity with which you determine the metric (and hence the gravitational field) from the distribution of matter and energy.
electromagnetism One of the four known forces; electromagnetism describes both electricity and magnetism.
electron A very light elementary particle with a negative charge.
electroweak theory The theory incorporating both electromagnetism and the weak force; an essential component of the Standard Model of particle physics.
equivalence principle The principle that uniform acceleration and gravity are indistinguishable.
eV (electronvolt) The energy required to move an electron against a potential difference of 1 volt.
external particles Real physical particles that can enter and leave an interaction region.
family See generation.
Fermi interaction An interaction that is generated by the exchange of one of the massive weak gauge bosons.
Fermilab A collider facility in Illinois; home of the Tevatron.
fermion A particle with half-integer spin—½, 3/2, etc. (one of two categories of particle established by quantum mechanics, the other being the boson); quarks and electrons are examples of fermions.
Feynman diagram A diagram that schematically illustrates allowed particle-physics interactions.
field A physical quantity that exists and has a particular value for each point in space. Examples include the classical electric field and quantum fields.
fine-tuning Fudging by adjusting a parameter to a very specific (and unlikely) value.
flavor A label that distinguishes different types of quark or lepton (often used to distinguish quarks and leptons from different generations).
flavor problem (of supersymmetry) The overly high prediction for flavor-changing processes (due to virtual squarks and sleptons) that plagues most models of supersymmetry breaking.
flavor symmetry Symmetry that interchanges different flavors of a particular particle category.
frame of reference An observational vantage point or a set of coordinates for describing events in space or spacetime.
gauge boson A particle that communicates an elementary force.
gaugino The superpartner of a force-carrying gauge boson.
gaugino mediation