kb/data/en.wikipedia.org/wiki/Glossary_of_string_theory-3.md

title	chunk	source	category	tags	date_saved	instance
Glossary of string theory	4/5	https://en.wikipedia.org/wiki/Glossary_of_string_theory	reference	science, encyclopedia	2026-05-05T07:51:24.096924+00:00	kb-cron

Majorana fermion Majorana spinor A fermion or spinor with a reality condition, in spacetimes of dimension 2, 3, 4 mod 8. Majorana–Weyl fermion Majorana–Weyl spinor A half-spinor with a reality condition, in spacetimes of dimension 2 mod 8. Mandelstam variable A sum or difference of two of the four incoming or outgoing momenta of a 2-particle interaction. matrix theory M(atrix) theory One of several non-perturbative formulations of string theory or M-theory using infinite matrices. M-brane membrane A higher dimensional analogue of a string. MC Monte Carlo integration

MCG

minimal model Certain solvable conformal field theories.

Mirror symmetry (string theory) A partly conjectural relation between a type IIA superstring theory compactified on a Calabi–Yau manifold and a type IIB superstring theory compactified on a different "mirror" Calabi–Yau manifold. MLLA Modified leading logarithm approximation.

MNS Maki–Nakagawa–Sakata matrix for neutrino mixing

monopole A hypothetical particle similar to a "magnet with only one pole". Montonen–Olive duality An early case of S-duality. MS minimal subtraction (a renormalization scheme). MS is the modified minimal subtraction scheme.

MSM Abbreviation for minimal standard model.

MSSM Abbreviation for minimal supersymmetric standard model.

mSUGRA Minimal model of supergravity.

M-theory

An 11-dimensional theory introduced in the second string theory revolution to unify the 5 known superstring theories. The letter M has been said to stand for membrane, matrix, magic, mystery, monster, and so on.

MSW Mikheyev–Smirnov–Wolfenstein effect concerning neutrino oscillations in matter.

multiplet A linear representation of a Lie algebra or group. A collection of elementary particles corresponding to a basis of a representation.

== N ==

N

1. The number of times each irreducible real spinor representation appears in the fermionic part of a supersymmetry algebra or super Minkowski space. It is often used in the description of an extended supersymmetry algebra, as in N=2 superconformal algebra and so on.
2. A nucleon, a baryon with 3 light quarks and isospin 1/2 (such as a proton or neutron).
3. The number of some type of particle.

Nambu–Goto action An action for strings, proportional to the area of the worldsheet. NC Neutral current (weak interaction).

Neumann Neumann boundary conditions on an open string say that the momentum normal to the boundary of the world-sheet is zero.

neutralino A hypothetical supersymmetric partner of a gauge boson with zero charge. Neveu Named for André Neveu.

Neveu–Schwarz algebra A supersymmetric extension of the Virasoro algebra, similar to the Ramond algebra. NG

1. Short for Nambu–Goto, as in Nambu–Goto action.
2. Short for Nambu–Goldstone, as in Nambu–Goldstone boson.

NLL Next to leading logarithmic (term).

NLO Next to leading order (term).

NLSP next-to-lightest sypersymmetric particle

NMSSM Next-to-Minimal Supersymmetric Standard Model.

NNLL Next to next to leading logarithmic (term).

NNLO Next to next to leading order (term).

NNNLL Next to next to next to leading logarithmic (term).

no-ghost theorem A theorem stating that some hermitian form is positive semidefinite, in other words has no ghosts (negative norm vectors). The name is a word-play on no-go theorem. NR Non-relativistic

NRQCD Non-relativistic quantum chromodynamics

NS Neveu–Schwarz, especially the Neveu–Schwarz algebra

NS–NS A sector with Neveu–Schwarz conditions on left and right moving modes.

NS–R A sector with Neveu–Schwarz conditions on left moving modes and Ramond conditions on right moving modes.

NUT The initials of E. Newman, L. Tamburino, and T. Unti, mainly used in Taub–NUT vacuum, a solution to Einsteins' equations.

== O ==

O An orthogonal group

OCQ Short for old covariant quantization

OPAL The OPAL detector at LEP.

open An open string is one with two ends.

OPE operator product expansion A description of short-distance singularities of fields. orbifold Something that looks locally like a manifold quotiented by the action of a finite group. OSp A Lie superalgebra.

== P ==

p A momentum

P

1. Parity, especially the parity symmetry.
2. Short for periodic, a boundary condition on strings (as opposed to A for antiperiodic).
3. Pseudoscalar (current)
4. Momentum
5. One of the bosonic elements of a supersymmetry algebra.

p-brane A p+1 dimensional membrane, where p is a non-negative integer. The dimension of membranes is often given by their space dimension, which is 1 less than their full spacetime dimension.

PCAC partially conserved axial vector current

PDF Parton distribution function.

PDG Particle Data Group.

photino A hypothetical supersymmetric partner of the photon. photon The neutral spin 1 gauge boson of the electromagnetic field. PMNS Pontecorvo–Maki–Nakagawa–Sakata matrix for neutrino mixing

Polyakov action A modification of the Nambu–Goto action for strings that eliminates the square root. PQ Peccei–Quinn, as in Peccei–Quinn theory.

pQCD PQCD Perturbative quantum chromodynamics.

prepotential A function used to construct the vector superfield in supersymmetric gauge theory and Seiberg–Witten theory.

primary field A field killed by the positive weight operators of the Virasoro algebra (or similar algebra); in other words, a lowest weight vector.

Princeton string quartet David Gross, Jeffrey Harvey, Emil Martinec, and Ryan Rohm, who introduced the heterotic string in 1985.

PSL Projective special linear group.

== Q ==

q A quark.

Q

1. The BRST operator.
2. A charge
3. One of the fermionic generators of a supersymmetry algebra.

quark A strongly interacting elementary particle of spin 1/2. QCD

QED

== R ==

R

1. Short for Ramond, as in Ramond sector.
2. A curvature tensor
3. An abbreviation for right (moving modes).
4. A radius
5. R-symmetry is a symmetry of extended supersymmetry algebras.

Ramond Named for Pierre Ramond.

Ramond algebra A supersymmetric extension of the Virasoro algebra, similar to the Neveu–Schwarz algebra. Rarita–Schwinger Refers to spin 3/2 fermions. Regge

1. Physicist Tullio Regge.
2. Regge trajectory: the squared mass of a hadronic resonance is roughly linear in the spin, with the constant of proportionality called the Regge slope.

revolution Any new idea in string theory. In particular the first superstring revolution refers to the discoveries in the mid 1980s such as the cancellation of gravitational anomalies and the heterotic string, and the second superstring revolution refers to the discoveries in the mid 1990s, such as D-branes, M-theory, and matrix theory and the AdS/CFT correspondence.

RG Renormalization group.