View source for Glossary of string theory

{{Short description|Terms in the theoretical physics framework}}
This page is a glossary of terms  in [[string theory]], including related areas such as [[supergravity]], [[supersymmetry]], and [[high energy physics]].

{{Compact ToC|short1|pre1=Conventions|pre2=αβγ|sym=yes|x=[[#XYZ|XYZ]]|y=|z=|seealso=yes|refs=yes}}

==Conventions==

{{glossary}}

{{term|-bein}}
{{defn|A suffix indicating a frame, where the first part is a German word indicating the dimension (as in zweibein, vierbein, and so on).}}

{{term|-ino}}
{{defn|The superpartners of bosons are often denoted by the suffix -ino; for example, [[photon]]/[[photino]].}}

{{term|s-}}
{{defn|The superpartners of fermions are often denoted by adding s- at the beginning; for example, [[quark]]/[[squark]].}}

{{glossary end}}

==αβγ==

{{glossary}}

{{term|α}}
{{defn|no=1|[[Fine-structure constant]]}}
{{defn|no=2|[[Regge slope]], or inverse of the [[string tension]]}}
How are these related?
There is only one dimensional constant in string theory, and that is the inverse string tension <math>\alpha^{\prime}</math> with units of area. Sometimes <math>\alpha^{\prime}</math> is therefore replaced by a length <math>l_s=\sqrt{\alpha^{\prime}}</math>. The string tension is mostly defined as the fraction
:<math>\frac{1}{2\pi\alpha^{\prime}}.</math>
Tension is energy or work per unit length. In natural units <math>c=1</math> and <math>\hbar=1</math>, and hence <math>\alpha^{\prime}</math> has dimension of length/energy or length/mass. Since <math>\hbar</math> has the dimension of action, i.e. momentum times length, it follows that in natural units mass =1/length, and so <math>\alpha^{\prime}</math> has the unit of area.
The slope <math>\alpha^{\prime}</math> of a Regge trajectory <math>\alpha(M^2)</math> in [[Regge theory]] is the derivative of spin <math>S</math> or angular momentum with respect to mass-squared, i.e.
:<math>\frac{dS}{dM^2}.</math>
Since angular momentum is moment of momentum <math>p</math>, i.e. length times mass with <math>c=1</math>, <math>S</math> is dimensionless in natural units, and <math>\alpha^{\prime}</math> has units of <math>1/M^2</math> or area like the inverse string tension. 

{{defn|no=3|A Fourier coefficient of a spacetime coordinate.}}
{{defn|no=4|α<sub>''s''</sub> is the [[strong coupling constant]]}}

{{term|β}}
{{defn|no=1|One of the two conformal superghost fields ''β'', ''γ'' used in the BRST quantization of the superstring}}
{{defn|no=2|[[Euler beta function]]}}
{{defn|no=3|[[beta function (physics)|Beta function]] describing the change of coupling constant under the renormalization group flow}}

{{term|γ}}
{{defn|no=1|[[Dirac matrix]]}}
{{defn|no=2|One of the two conformal superghost fields ''β'', ''γ'' used in the BRST quantization of the superstring}}
{{defn|no=3|World-sheet metric γ<sub>''ab''</sub>(σ,τ)}}
{{defn|no=4|Photon}}
{{defn|no=5|[[Euler constant]] .57721...}}

{{term|Γ}}
{{defn|no=1|Lattice}}
{{defn|no=2|Euler [[Gamma function]]}}
{{defn|no=3|[[Dirac matrix]]}}
{{defn|no=4|Width of some scattering process}}

{{term|δ}}
{{defn|no=1|[[Kronecker delta function]]}}
{{defn|no=2|An infinitesimal change in something; for example δ''L'' is an infinitesimal change in ''L''}}

{{term|Δ}}
{{defn|no=1|Propagator}}
{{defn|no=2|[[Delta baryon]], a baryon with 3 light quarks and isospin 3/2}}
{{defn|no=3|[[Laplace operator]] in Euclidean space or more generally a Riemannian manifold}}

{{term|ε}}
{{defn|no=1|Small positive real number}}
{{defn|no=2|Antisymmetric tensor}}

{{term|η}}
{{defn|no=1|Flat Lorentzian metric on spacetime}}
{{defn|no=2|[[Dedekind eta function]], a weight 1/2 modular form}}
{{defn|no=3|1=[[Eta meson]], a neutral flavor meson with [[Parity (physics)|P]][[C parity|C]] = –+}}

{{term|θ}}
{{defn|no=1|[[Theta function]]}}
{{defn|no=2|θ<sub>c</sub> is the [[Cabbibo angle]]}}
{{defn|no=3|θ<sub>w</sub> is the [[Weinberg angle]], also called the weak mixing angle}}

{{term|Λ}}
{{defn|no=1|[[Cosmological constant]]}}
{{defn|no=2|Large energy or large mass cutoff in regularization}}
{{defn|no=3|[[Lambda baryon]], a baryon with 2 light quarks and isospin 0}}

{{term|μ}}
{{defn|no=1|Renormalization scale, with the dimensions of mass}}
{{defn|no=2|[[Muon]]}}

{{term|ν}}
{{defn|[[Neutrino]]}}

{{term|Ξ}}
{{defn|no=1|[[Xi baryon]], a baryon with 1 light quark}}

{{term|π}}
{{defn|no=1|[[Pi|3.14159...]]}}
{{defn|no=2|[[Pion]]}}

{{term|Π}}
{{defn|The momentum density conjugate to ''X''}}

{{term|ρ}}
{{defn|1=[[Rho meson]], a light meson with PC = ––}}

{{term|σ}}
{{defn|no=1|Spacelike coordinate on the world-sheet}}
{{defn|no=2|Scattering cross section}}
{{defn|no=3|[[Pauli matrix]]}}
{{defn|no=4|See [[#sigma model]]}}

{{term|Σ}}
{{defn|no=1|[[Sigma baryon]], a baryon with 2 light quarks and isospin 1}}

{{term|τ}}
{{defn|no=1|Timelike coordinate on the world-sheet}}
{{defn|no=2|Element of the [[upper half plane]]}}
{{defn|no=3|[[Tauon]]}}

{{term|Υ}}
{{defn|[[Upsilon meson]] (b{{overline|b}})}}

{{term|φ}}
{{defn|Scalar field}}

{{term|χ}}
{{defn|1=Neutral-flavor heavy meson with PC = ++}}

{{term|ψ}}
{{defn|no=1|Spinor field}}
{{defn|no=2|[[Psi meson]] (c{{overline|c}}) }}

{{term|Ω}}
{{defn|no=1|Density of something in the universe; for example, Ω<sub>ν</sub> is the neutrino density}}
{{defn|no=2|[[Omega baryon]], a baryon with no light quarks}}

{{glossary end}}

==!$@==

{{glossary}}

{{term|' (prime)}}
{{defn|''X''&prime; means ∂''X''/∂σ.}}

{{term|dot above letter}}
{{defn|Ẋ means ∂''X''/∂τ}}

{{term|∇}}
{{defn|no=1|A covariant derivative}}
{{defn|no=2|The [[del]] operator.}}

{{term|□}}
{{defn|The [[D'Alembert operator]], or non-Euclidean Laplacian.}}

{{term|[,] }}
{{defn|1=A commutator: [''A'',''B''] = ''AB''–''BA''.}}

{{term|{,} }}
{{defn|1=An anticommutator: {''A'',''B''} = ''AB''+''BA''.}}

{{glossary end}}

==A==

{{glossary}}

{{term|A}}
{{defn|no=1|A connection 1-form}}
{{defn|no=2|Short for antiperiodic, a boundary condition on strings.}}
{{defn|no=3|Short for [[axial vector]]}}
{{defn|no=4|An asymmetry}}

{{term|action}}
{{defn|{{main|action (physics)}} A function ''S'' on the space of fields given (formally) by the integral of the Lagrangian density over spacetime, whose stationary points are the solutions of the equations of motion.}}

{{term|ADE}}
{{defn|{{main|ADE classification}} Refers to the ADE classification (A<sub>''n''</sub>,D<sub>n</sub>, E<sub>6</sub>, E<sub>7</sub>, E<sub>8</sub>)  of simply laced [[Dynkin diagram]]s, and to several related classifications of Lie algebras, singularities and so on. }}

{{term|ADHM}}
{{defn|Initials of Atiyah, Drinfeld, Hitchin, and Manin, as in the [[ADHM construction]] of instantons.}}

{{term|ADM}}
{{defn|Initials of Arnowitt, Deser, and Misner, as in [[ADM energy]], a way of defining the global energy in an asymptotically flat spacetime, or [[ADM decomposition]] of a metric, or [[ADM formalism]].}}

{{term|AdS}}
{{defn|Anti-de Sitter, as in [[anti-de Sitter space]], a Lorentzian analogue of hyperbolic space}}

{{term|AdS/CFT}}
{{defn|Anti-de Sitter/conformal field theory, especially the [[AdS/CFT correspondence]].}}

{{term|ALE}}
{{defn|[[Asymptotically locally Euclidean]]}}

{{term|ALEPH}}
{{defn|[[ALEPH experiment]] at LEP}}

{{term|AMSB}}
{{defn|Anomaly mediation supersymmetry breaking}}

{{term|ASD}}
{{defn|Anti self-dual (connection)}}

{{term|ATLAS}}
{{defn|The [[ATLAS experiment]] at [[CERN]], a particle detector.}}

{{term|axino}}
{{defn|{{main|Axino}} A hypothetical supersymmetric partner of an axion.}}

{{term|axion}}
{{defn|{{main|Axion}} A hypothetical scalar particle whose mass arises from a coupling rather than from a mass term in the Lagrangian, used to resolve the [[strong CP problem]].}}

{{glossary end}}

==B==

{{glossary}}

{{term|b}}
{{defn|no=1|One of the two conformal ghost fields ''b'', ''c'' used in the BRST quantization of the bosonic string.}}
{{defn|no=2|A [[bottom quark]].}}

{{term|B}}
{{defn|no=1|[[Baryon number]]}}
{{defn|no=2|Short for [[boson]].}}
{{defn|no=3|Short for [[baryon]].}}
{{defn|no=4|Short for backward;for example, σ<sub>''B''</sub> is the cross section for backward scattering.}}
{{defn|no=5|a [[bottom meson]].}}

{{term|BAO}}
{{defn|[[Baryon acoustic oscillation]]}}

{{term|BB}}
{{defn|[[Big Bang]]}}

{{term|BBN}}
{{defn|[[Big Bang]] [[nucleosynthesis]]}}

{{term|bino}}
{{defn|{{main|gaugino}} A hypothetical supersymmetric partner of the gauge field corresponding to weak hypercharge.}}

{{term|BIon}}
{{defn|A BPS solution representing an infinite string ending on a D-brane. Named after the [[Born–Infeld action]].}}

{{term|BPS}}
{{defn|{{main|BPS state}} A state related to the [[Bogomol'nyi–Prasad–Sommerfield bound]]. }}

{{term|BR}}
{{defn|Branching ratio}}

{{term|BRS}}
{{term|BRST quantization}}
{{defn|{{main|BRST quantization}} Short for Becchi, Rouet, Stora and Tyutin, who introduced the [[BRST quantization]] of gauge theories.}}

{{term|brane}}
{{defn|Short for membrane. a higher-dimensional manifold moving in spacetime. See also p-brane, D-brane.}}

{{term|BTZ}}
{{defn|Initials of Bañados–Teitelboim–Zanelli, as in [[BTZ black hole]], a black hole in 2+1-dimensional gravity.}}

{{term|BV}}
{{defn|Batalin–Vilkovisky, as in [[Batalin–Vilkovisky formalism]].}}

{{glossary end}}

==C==

{{glossary}}

{{term|c}}
{{defn|no=1|The [[speed of light]], when not using units where this is 1.}}
{{defn|no=2|A central charge of the Virasoro algebra or similar algebra.}}
{{defn|no=3|One of the two conformal ghost fields ''b'', ''c'' used in the BRST quantization of the bosonic string.}}
{{defn|no=4|A [[Chern class]].}}
{{defn|no=5|A [[charm quark]].}}

{{term|C}}
{{defn|no=1|Charge, especially the [[charge symmetry]].}}

{{term|Calabi–Yau}}
{{defn|{{main|Calabi–Yau manifold}} A [[Kähler manifold]] with vanishing [[Ricci curvature]], used for compactifying string theories.}}

{{term|CAR}}
{{defn|[[Canonical anticommutation relations]]}}

{{term|CBR}}
{{defn|[[Cosmic background radiation]]}}

{{term|CC}}
{{defn|no=1|Charged current (weak interaction).}}
{{defn|no=2|Complex conjugate}}
{{defn|no=3|Compatibility condition}}

{{term|CCR}}
{{defn|[[Canonical commutation relation]]}}
{{defn|[[CCR and CAR algebras]]}}

{{term|CDF}}
{{defn|[[Collider Detector at Fermilab]]}}

{{term|CDM}}
{{defn|[[Cold dark matter]]}}

{{term|CERN}}
{{defn|[[Conseil Européen pour la Recherche Nucléaire]]}}

{{term|chargino}}
{{defn|{{main|chargino}} A hypothetical charged supersymmetric partner of a [[gauge boson]].}}

{{term|Chern–Simons}}
{{defn|no=1|{{main|Chern–Simons theory}} }}
{{defn|no=2|{{main|Chern–Simons form}} }}

{{term|chiral}}
{{defn|no=1|Not invariant under the parity symmetry. The word comes from the Greek χειρ meaning "hand"; the terms "left-handed" and "right-handed" are often used to describe chiral objects. {{main|Chirality (physics)}}}}
{{defn|no=2|A '''chiral multiplet''' is a type of supermutliplet of a supersymmetry algebra.}}

{{term|CIPT}}
{{defn|Contour improved perturbation theory}}

{{term|CKG}}
{{defn|Short for conformal Killing group.}}

{{term|CKM}}
{{defn|The [[Cabibbo–Kobayashi–Maskawa matrix]].}}

{{term|CKS}}
{{defn|Short for conformal Killing spinor.}}

{{term|CKV}}
{{defn|Short for conformal [[Killing vector]].}}

{{term|CFT}}
{{defn|[[Conformal field theory]]}}

{{term|Chan–Paton}}
{{defn|A [[Chan–Paton charge]] is a degree of freedom carried by an open string on its endpoints.}}

{{term|cl}}
{{defn|no=1|Short for classical (for example, ''S''<sub>''cl''</sub> is the classical action).}}
{{defn|no=2|CL is short for confidence limit.}}

{{term|closed}}
{{defn|A closed string is one with no ends.}}

{{term|CM}}
{{defn|Center of mass (frame)}}

{{term|CMB}}
{{term|CMBR}}
{{defn|[[Cosmic microwave background]] radiation}}

{{term|CMS}}
{{defn|no=1|The [[Compact Muon Solenoid]] at [[CERN]], a particle detector.}}
{{defn|no=2|Short for the Center-of-Momentum System, a coordinate system where the total momentum is 0.}}

{{term|compactification}}
{{defn|A method for reducing the apparent dimension of spacetime by wrapping the string around a compact manifold.}}

{{term|cosmological constant}}
{{defn|{{main|cosmological constant}} The constant term of the Lagrangian, inducing a term in the action proportional to the volume of spacetime}}

{{term|CP}}
{{defn|Short for Charge–Parity, as in [[CP symmetry]].}}

{{term|CPC}}
{{defn|Short for Charge–Parity conservation.}}

{{term|CPT}}
{{defn|Short for Charge–Parity–Time, as in [[CPT symmetry]] or [[CPT theorem]].}}

{{term|CPV}}
{{defn|Short for Charge–Parity violation.}}

{{term|critical}}
{{defn|The '''critical dimension''' is the spacetime dimension in which a string or superstring theory is consistent; usually 26 for string theories and 10 for superstring theories.}}

{{term|CVC}}
{{defn|Conserved [[vector current]].}}

{{term|CY}}
{{defn|Short for Calabi–Yau, as in [[Calabi–Yau manifold]], a Ricci-flat Kähler manifold, often used for compactifying superstring theories.}}

{{glossary end}}

==D==

{{glossary}}

{{term|d}}
{{defn|no=1|The [[exterior derivative]] of a form.}}
{{defn|no=2|A [[down quark]].}}
{{defn|no=3|The dimension of spacetime.}}

{{term|D}}
{{defn|no=1|Short for Dirichlet, as in D-brane}}
{{defn|no=2|The dimension of spacetime}}
{{defn|no=3|A connection or differential operator}}
{{defn|no=4|A [[Dynkin diagram]] of an orthogonal group in even dimensions.}}
{{defn|no=5|A [[charm quark|charmed meson]].}}

{{term|D0}}
{{defn|{{main|DØ experiment}} }}

{{term|D-brane}}
{{term|Dp-brane}}
{{defn|{{main|D-brane}} Short for Dirichlet (mem)brane, a submanifold (of dimension ''p''+1) on which the ends of strings are constrained to lie, so that the strings satisfy Dirichlet boundary conditions.}}

{{term|D-string}}
{{defn|A D1-brane}}

{{term|DBI}}
{{defn|Short for Dirac–Born–Infeld, as in the [[DBI action]], an action based on the [[Born–Infeld action]], a modification of the Maxwell action of electrodynamics.}}

{{term|DDF}}
{{defn|Initials of Del Guidice, Di Vecchia, and Fubini, as in  [[Del Guidice–Di Vecchia–Fubini operator]], operators generating an oscillator algebra.}}

{{term|DELPHI}}
{{defn|[[DELPHI experiment]] at LEP.}}

{{term|DESY}}
{{defn|[[Deutsches Elektronen-Synchrotron]]}}

{{term|DGLAP}}
{{defn|Initials of Dokshitzer–Gribov–Lipatov–Altarelli–Parisi who introduced the [[DGLAP]] evolution equation in QCD.}}

{{term|Diff}}
{{defn|[[Diffeomorphism]] or [[diffeomorphism group]].}}

{{term|dilatino}}
{{defn|{{main|dilatino}} A supersymmetric partner of the dilaton.}}

{{term|dilaton}}
{{defn|{{main|dilaton}} A massless scalar particle, related to dilations of spacetime.}}

{{term|Dirichlet}}
{{defn|[[Dirichlet boundary condition]]s on an open string say that the ends of the string are fixed (often lying on a D-brane). }}

{{term|DIS}}
{{defn|[[Deep inelastic scattering]]}}

{{term|DLCQ}}
{{defn|Discrete light-cone quantization}}

{{term|DM}}
{{defn|Dark matter}}

{{term|DØ}}
{{defn|{{main|DØ experiment}} }}

{{term|Dp-brane}}
{{defn|{{main|D-brane}} Short for Dirichlet (mem)brane, a submanifold (of dimension ''p''+1) on which the ends of strings are constrained to lie, so that the strings satisfy Dirichlet boundary conditions.}}

{{term|DR}}
{{defn|no=1|Short for [[dimensional regularization]].}}
{{defn|no=2|Short for [[dimensional reduction]], a way of constructing theories from simpler theories in higher dimensions, sometimes by making fields invariant under some spacelike translations.}}

{{term|dS}}
{{defn|de Sitter, as in [[de Sitter space]], a Lorentzian analogue of a sphere}}

{{term|dS/CFT}}
{{defn|de Sitter/conformal field theory, especially the [[dS/CFT correspondence]].}}

{{term|dual resonance model}}
{{defn|{{main|Dual resonance model}} An early precursor of string theory.}}

{{term|duality}}
{{defn|{{main|String duality}} A hidden connection between two different theories, such as [[S-duality]], [[T-duality]], [[U-duality]], [[mysterious duality]].}}

{{term|DY}}
{{defn|Initials of Drell–Yan, as in [[DY process]].}}

{{term|dyon}}
{{defn|{{main|Dyon}} A hypothetical particle with both electrical and magnetic charge.}}

{{glossary end}}

==E==

{{glossary}}

{{term|e}}
{{defn|no=1|[[Euler's constant]]}}
{{defn|no=2|A frame}}
{{defn|no=3|An electron}}

{{term|E}}
{{defn|Energy}}

{{term|E6}}
{{defn|{{main|E6 (mathematics)}} E<sub>6</sub> is the exceptional Lie algebra of rank 6 and dimension 78.}}

{{term|E7}}
{{defn|{{main|E7 (mathematics)}} E<sub>7</sub> the exceptional Lie algebra of rank 7 and dimension 133.}}

{{term|E8}}
{{defn|{{main|E8 (mathematics)}} E<sub>8</sub> the exceptional Lie algebra of rank 8 and dimension 248.}}

{{term|eff}}
{{defn|Short for effective (field theory).}}

{{term|EFT}}
{{defn|[[Effective field theory]], a low-energy approximation to a theory.}}

{{term|einbein}}
{{defn|A frame in 1 dimension}}

{{term|elfbein}}
{{defn|A frame in 11 dimensions}}

{{term|energy–momentum tensor}}
{{defn|{{main|Energy–momentum tensor}} A symmetric tensor ''T'' (also called the stress-energy tensor) describing the variation of the action under changes in the metric, whose components give the local energy, momentum and stress densities. In flat spacetimes it can also be given by combining the Noether currents of the translation symmetries.}}

{{term|EWSB}}
{{defn|Electro-weak symmetry breaking.}}

{{glossary end}}

==F==

{{glossary}}

{{term|F}}
{{defn|no=1|A [[curvature form]] of a connection}}
{{defn|no=2|The world-sheet [[fermion number]].}}
{{defn|no=3|Short for fermion}}
{{defn|no=3|Short for forward;for example, σ<sub>''F''</sub> is the cross section for backward scattering.}}

{{term|F4}}
{{defn|{{main|F4 (mathematics)}} F<sub>4</sub> is the exceptional Lie algebra of rank 4 and dimension 52.}}

{{term|FCNC}}
{{defn|Flavor-changing [[neutral current]].}}

{{term|field}}
{{defn|A section of a fiber bundle}}

{{term|FOPT}}
{{defn|Fixed-order perturbation theory.}}

{{term|F-string}}
{{defn|Fundamental string}}

{{term|F-theory}}
{{defn|{{main|F-theory}} Possibly an abbreviation of father theory. A 12-dimensional string theory introduced by Vafa.  }}

{{term|FRW}}
{{defn|[[Friedman–Robertson–Walker]] metric on spacetime}}

{{glossary end}}

==G==

{{glossary}}

{{term|g}}
{{defn|no=1|A metric}}
{{defn|no=2|A coupling constant}}
{{defn|no=3|The [[genus of a Riemann surface]].}}
{{defn|no=4|A [[gluon]].}}

{{term|G}}
{{defn|no=1|Newton's [[gravitational constant]], sometimes written ''G''<sub>''N''</sub>.}}
{{defn|no=2|The [[Fermi coupling constant]] for weak interactions, sometimes written ''G''<sub>''F''</sub>.}}
{{defn|no=3|''G''<sub>''n''</sub> is an odd element of the Ramond or Neveu–Schwarz superalgebra.}}

{{term|G2}}
{{defn|{{main|G2 (mathematics)}} The exceptional Lie algebra of rank 2 and dimension 14, or a [[G2 manifold]] with G<sub>2</sub> holonomy.}}

{{term|gaugino}}
{{defn|A spin 1/2 supersymmetric partner of a gauge boson.}}

{{term|gh}}
{{defn|Abbreviation for ghost; for example, ''S''<sub>''gh''</sub> is the ghost action.}}

{{term|ghost}}
{{defn|A vector of negative norm.}}

{{term|GKO}}
{{Defn|Short for Goddard–Kent–Olive. The GKO construction, also called the [[coset construction]], is a way of constructing unitary discrete series representations of the Virasoro algebra.}}

{{term|GL}}
{{defn|A [[general linear group]].}}

{{term|gluino}}
{{defn|{{main|gluino}} A hypothetical supersymmetric partner of a [[gluon]].}}

{{term|gluon}}
{{defn|{{main|gluon}} A [[gauge boson]] associated with the [[strong force]].}}

{{term|GMSB}}
{{defn|Gauge mediated supersymmetry breaking.}}

{{term|goldstino}}
{{defn|{{main|goldstino}} A massless spin 1/2 particle associated with spontaneous breakdown of supersymmetry, analogous to the [[Goldstone boson]].}}

{{term|GR}}
{{defn|[[General relativity]]}}

{{term|graviton}}
{{defn|{{main|graviton}} A conjectural spin 2 massless particle responsible for gravity.}}

{{term|gravitino}}
{{defn|{{main|gravitino}} A supersymmetric partner of the graviton.}}

{{term|Green}}
{{defn|Named for [[Michael Green (physicist)|Michael Green]].}}

{{term|GS}}
{{defn|Green–Schwarz formalism, a way of incorporating supersymmetry into string theory that is supersymmetric in 10-dimensional spacetime.}}

{{term|GSO}}
{{defn|Short for Ferdinando Gliozzi, Joël Scherk, and David A. Olive, as in the [[GSO projection]], a projection in superstring theory that eliminates tachyons.}}

{{term|GSW}}
{{defn|The 2-volume work on superstring theory by Green, Schwarz, and Witten.}}

{{term|GUT}}
{{defn|[[Grand unified theory]], a hypothetical theory unifying the strong and electroweak forces.}}

{{term|GWS}}
{{defn|Glashow–Weinberg–Salem theory of the [[electroweak force]].}}

{{term|GZK}}
{{defn|The [[Greisen–Zatsepin–Kuzmin limit]] on the energy of cosmic background radiation from distant sources.}}

{{glossary end}}

==H==

{{glossary}}

{{term|h}}
{{defn|no=1|The weight of a field (for example, its eigenvalue for ''L''<sub>0</sub>).}}
{{defn|no=2|Hermitian; for example, h.c. stands form hermitian conjugate.}}

{{term|H}}
{{defn|no=1|The [[Hamiltonian mechanics|Hamiltonian]].}}
{{defn|no=2|The [[Higgs boson]].}}
{{defn|no=3|The [[Hubble constant]].}}

{{term|Haag–Łopuszański–Sohnius theorem}}
{{defn|{{main|Haag–Łopuszański–Sohnius theorem}} A theorem describing the possible supersymmetries of a quantum field theory, generalizing the [[Coleman–Mandula theorem]].}}

{{term|Hagedorn temperature}}
{{defn|{{main|Hagedorn temperature}} The temperature above which the partition function diverges due to the exponentially increasing number of string states.}}

{{term|h.c.}}
{{term|hc}}
{{defn|Hermitian conjugate}}

{{term|HCMS}}
{{defn|Hadronic center of mass (frame)}}

{{term|HDM}}
{{defn|Higgs doublet model}}

{{term|HE}}
{{defn|Short for heterotic-E{{su|b=8|p=2}}, a heterotic string theory based on the group E{{su|b=8|p=2}}.}}

{{term|helicity}}
{{defn|{{main|Helicity (particle physics)}} The projection of the spin of a massless particle in the direction of its momentum.}}

{{term|HERA}}
{{defn|[[Hadron Elektron Ring Anlage]]}}

{{term|heterotic}}
{{defn|{{main|heterotic string}} Named after the Greek word [[heterosis]], meaning hybrid vigour. A hybrid of bosonic string theory and superstring theory, introduced by David Gross, Jeffrey Harvey, Emil Martinec, and Ryan Rohm in 1985.}}

{{term|Higgs boson}}
{{defn|{{main|Higgs boson}}  A massive scalar particle related to the spontaneous symmetry breaking mechanism in the electroweak theory.}}

{{term|Higgsino}}
{{defn|{{main|Higgsino}} A hypothetical supersymmetric partner of a [[Higgs boson]].}}

{{term|HO}}
{{defn|Short for heterotic-orthogonal, a heterotic string theory based on the orthogonal group O<sub>32</sub>('''R''').}}

{{term|holographic principle}}
{{defn|{{main|Holographic principle}} }}

{{term|HQET}}
{{defn|{{main|Heavy quark effective theory}} }}

{{term|Hyperkähler}}
{{term|Hyperkaehler}}
{{defn|{{main|Hyperkähler manifold}} A Riemannian manifold with holonomy contained in the compact form of the symplectic group.}}

{{term|Hypermultiplet}}
{{defn|{{main|Hypermultiplet}} A type of supermultiplet (representation) of an extended supersymmetry algebra.}}

{{glossary end}}

==I==

{{glossary}}

{{term|i}}
{{defn|{{radic|–1}}}}

{{term|I}}
{{defn|[[Isospin]].}}

{{term|IGM}}
{{defn|[[Intergalactic medium]]}}

{{term|inflation}}
{{defn|{{main|Inflation (cosmology)}} A hypothetical very rapid increase in the size of the very early universe.}}

{{term|instanton}}
{{defn|{{main|Instanton}} A self-dual or anti-self-dual connection in a principal bundle over a four-dimensional Riemannian manifold.}}

{{term|int}}
{{defn|Short for interaction; for example, ''H''<sub>int</sub> might be an interaction Hamiltonian.}}

{{term|inv}}
{{defn|Short for invisible; for example, Γ<sub>inv</sub> is the width for invisible decays (those unobseverd by an experiment).}}

{{glossary end}}

==J==

{{glossary}}

{{term|J}}
{{defn|no=1|A current}}
{{defn|no=2|A source}}
{{defn|no=3|Spin.}}

{{glossary end}}

==K==

{{glossary}}

{{term|k}}
{{defn|A momentum}}

{{term|K}}
{{defn|A [[kaon]] (a strange meson).}}

{{term|K3}}
{{defn|{{main|K3 surface}} A simply connected compact complex surface of [[Kodaira dimension]] 0}}

{{term|K-theory}}
{{defn|{{main|K-theory|K-theory (physics)}} A cohomology theory based on vector bundles.}}

{{term|Kac–Moody algebra}}
{{defn|{{main|Kac–Moody algebra}} A central extension of a [[loop algebra]].}}

{{term|Kähler}}
{{term|Kaehler}}
{{defn|Named after [[Erich Kähler]]}}
{{defn|no=1|A [[Kähler manifold]] is a complex manifold with a compatible Riemannian metric.}}
{{defn|no=2|A [[Kähler metric]] is the metric on a Kähler manifold.}}
{{defn|no=3|A [[Kähler potential]] is a function of superfields used to construct a Lagrangian.}}

{{term|Kalb–Ramond field}}
{{defn|{{main|Kalb–Ramond field}} }}

{{term|KK}}
{{defn|[[Kaluza–Klein]]}}

{{term|KM}}
{{defn|no=1|The [[Kobayashi–Maskawa mechanism]] for CP violation.}}
{{defn|no=2|[[Kac–Moody algebra]].}}

{{term|KZ}}
{{defn|Initials of Knizhnik and Zamolodchikov, as in [[KZ equation]], a differential equation related to the primary fields of a current algebra.}}

{{glossary end}}

==L==

{{glossary}}

{{term|L}}
{{defn|no=1|A [[Lagrangian (field theory)|Lagrangian]]}}
{{defn|no=2|''L''<sub>''n''</sub> is an element of the [[Virasoro algebra]].}}
{{defn|no=3|An abbreviation for left (moving modes).}}
{{defn|no=4|Lepton number}}
{{defn|no=5|Short for lepton}}

{{term|L3}}
{{defn|[[L3 experiment]] at LEP.}}

{{term|Lagrangian (field theory)}}
{{defn|{{main|Lagrangian (field theory)}} A function on the jet space of a fiber bundle.}}

{{term|landscape}}
{{defn|{{main|String theory landscape}} The (conjectural) moduli space of all (vacuums of) string theories.}}

{{term|LEP}}
{{defn|The [[Large Electron–Positron Collider]] at CERN.}}

{{term|lepton}}
{{defn|{{main|lepton}} An elementary particle of spin 1/2 that is unaffected by the strong force.}}

{{term|LH}}
{{defn|Left-handed}}

{{term|LHC}}
{{defn|The [[large hadron collider]] at [[CERN]]. }}

{{term|little string theory}}
{{defn|{{main|Little string theory}} }}

{{term|LL}}
{{defn|Double logarithmic}}

{{term|LO}}
{{defn|[[leading-order|Leading order]] (term)}}

{{term|LQG}}
{{defn|[[Loop quantum gravity]]}}

{{term|LQC}}
{{defn|[[Loop quantum cosmology]]}}

{{term|LSP}}
{{defn|Abbreviation for [[lightest supersymmetric particle]].}}

{{term|LSS}}
{{defn|Large scale structure (of the universe).}}

{{glossary end}}

==M==

{{glossary}}

{{term|m}}
{{defn|A mass of a fermion. For example, ''m''<sub>''t''</sub> is the mass of the top quark ''t''.}}

{{term|M}}
{{defn|The mass of a boson; for example, ''M''<sub>''Z''</sub> is the mass of the Z-boson.}}

{{term|Majorana fermion}}
{{term|Majorana spinor}}
{{defn|{{main|Majorana fermion|Majorana spinor}} A fermion or spinor with a reality condition, in spacetimes of dimension   2, 3, 4 mod 8.}}

{{term|Majorana–Weyl fermion}}
{{term|Majorana–Weyl spinor}}
{{defn|{{main|Majorana–Weyl fermion|Majorana–Weyl spinor}} A half-spinor with a reality condition, in spacetimes of dimension 2 mod 8.}}

{{term|Mandelstam variable}}
{{defn|{{main|Mandelstam variables}} A sum or difference of two of the four incoming or outgoing momenta of a 2-particle interaction.}}

{{term|matrix theory}}
{{term|M(atrix) theory}}
{{defn|{{main|Matrix string theory}} One of several non-perturbative formulations of string theory or M-theory using infinite matrices.}}

{{term|M-brane}}
{{term|membrane}}
{{defn|{{main|Membrane (M-theory)}} A higher dimensional analogue of a string.}}

{{term|MC}}
{{defn|[[Monte Carlo integration]]}}

{{term|MCG}}
{{defn|{{main|Mapping class group}} }}

{{term|minimal model}}
{{defn|Certain solvable [[conformal field theories]].}}

{{term|Mirror symmetry (string theory)}}
{{defn|{{main|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.}}

{{term|MLLA}}
{{defn|Modified leading logarithm approximation.}}

{{term|MNS}}
{{defn| [[Maki–Nakagawa–Sakata matrix]] for neutrino mixing}}

{{term|monopole}}
{{defn|{{main|Magnetic monopole|Dirac monopole|Wu–Yang monopole|'t Hooft–Polyakov monopole|Seiberg-Witten monopole|Monopole (mathematics)}}  A hypothetical particle similar to  a "magnet with only one pole".}}

{{term|Montonen–Olive duality}}
{{defn|{{main|Montonen–Olive duality}} An early case of [[S-duality]].}}

{{term|MS}}
{{defn|[[minimal subtraction]] (a renormalization scheme). {{overline|MS}} is the [[modified minimal subtraction scheme]].}}

{{term|MSM}}
{{defn|Abbreviation for [[minimal standard model]].}}

{{term|MSSM}}
{{defn|Abbreviation for [[minimal supersymmetric standard model]].}}

{{term|mSUGRA}}
{{defn|[[mSUGRA|Minimal model of supergravity]].}}

{{term|M-theory}}
{{defn|{{main|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.}}

{{term|MSW}}
{{defn|[[Mikheyev–Smirnov–Wolfenstein effect]] concerning neutrino oscillations in matter.}}

{{term|multiplet}}
{{defn|A linear representation of a Lie algebra or group.}}
{{defn|A collection of elementary particles corresponding to a basis of a representation.}}

{{glossary end}}

==N==

{{glossary}}

{{term|N}}
{{defn|no=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.}}
{{defn|no=2|A [[nucleon]], a baryon with 3 light quarks and isospin 1/2 (such as a [[proton]] or [[neutron]]).}}
{{defn|no=3|The number of some type of particle.}}

{{term|Nambu–Goto action}}
{{defn|{{main|Nambu–Goto action}} An action for strings, proportional to the area of the worldsheet.}}

{{term|NC}}
{{defn|Neutral current (weak interaction).}}

{{term|Neumann}}
{{defn|[[Neumann boundary condition]]s on an open string say that the momentum normal to the boundary of the world-sheet is zero. }}

{{term|neutralino}}
{{defn|{{main|Neutralino}} A hypothetical supersymmetric partner of a [[gauge boson]] with zero charge.}}

{{term|Neveu}}
{{defn|Named for [[André Neveu]].}}

{{term|Neveu–Schwarz algebra}}
{{defn|{{main|Neveu–Schwarz algebra}} A supersymmetric extension of the [[Virasoro algebra]], similar to the [[Ramond algebra]].}}

{{term|NG}}
{{defn|no=1|Short for Nambu–Goto, as in [[Nambu–Goto action]].}}
{{defn|no=2|Short for Nambu–Goldstone, as in [[Nambu–Goldstone boson]].}}

{{term|NLL}}
{{defn|Next to leading  logarithmic (term).}}

{{term|NLO}}
{{defn|Next to leading order (term).}}

{{term|NLSP}}
{{defn|next-to-lightest sypersymmetric particle}}

{{term|NMSSM}}
{{defn|[[Next-to-Minimal Supersymmetric Standard Model]].}}

{{term|NNLL}}
{{defn|Next to next to leading  logarithmic (term).}}

{{term|NNLO}}
{{defn|Next to next to leading order (term).}}

{{term|NNNLL}}
{{defn|Next to next to next to leading  logarithmic (term).}}

{{term|no-ghost theorem}}
{{defn|{{main|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]].}}

{{term|NR}}
{{defn|Non-relativistic}}

{{term|NRQCD}}
{{defn|Non-relativistic quantum chromodynamics}}

{{term|NS}}
{{defn|Neveu–Schwarz, especially the [[Neveu–Schwarz algebra]]}}

{{term|NS–NS}}
{{defn|A sector with Neveu–Schwarz conditions on left and right moving modes.}}

{{term|NS–R}}
{{defn|A sector with Neveu–Schwarz conditions on left moving modes and Ramond conditions on right moving modes.}}

{{term|NUT}}
{{defn|The initials of E. Newman, L. Tamburino, and T. Unti, mainly used in [[Taub–NUT vacuum]], a solution to Einsteins' equations.}}
 
{{glossary end}}

==O==

{{glossary}}

{{term|O}}
{{defn|An [[orthogonal group]]}}

{{term|OCQ}}
{{defn|Short for old covariant quantization}}

{{term|OPAL}}
{{defn|The [[OPAL detector]] at LEP.}}

{{term|open}}
{{defn|An open string is one with two ends.}}

{{term|OPE}}
{{term|operator product expansion}}
{{defn|{{main|Operator product expansion}} A description of short-distance singularities of fields.}}

{{term|orbifold}}
{{defn|{{main|orbifold}} Something that looks locally like a manifold quotiented by the action of a finite group.}}

{{term|OSp}}
{{defn|A [[Lie superalgebra]].}}

{{glossary end}}

==P==

{{glossary}}

{{term|p}}
{{defn|A momentum}}

{{term|P}}
{{defn|no=1|Parity, especially the [[parity symmetry]].}}
{{defn|no=2|Short for periodic, a boundary condition on strings (as opposed to A for antiperiodic).}}
{{defn|no=3|[[Pseudoscalar]] (current)}}
{{defn|no=4|Momentum}}
{{defn|no=5|One of the bosonic elements of a [[supersymmetry algebra]].}}

{{term|''p''-brane}}
{{defn|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.}}

{{term|PCAC}}
{{defn|[[partially conserved axial vector current]]}}

{{term|PDF}}
{{defn|[[Parton distribution function]].}}

{{term|PDG}}
{{defn|[[Particle Data Group]].}}

{{term|photino}}
{{defn|{{main|photino}} A hypothetical supersymmetric partner of the photon.}}

{{term|photon}}
{{defn|{{main|photon}} The neutral spin 1 gauge boson of the electromagnetic field.}}

{{term|PMNS}}
{{defn| [[Pontecorvo–Maki–Nakagawa–Sakata matrix]] for neutrino mixing}}

{{term|Polyakov action}}
{{defn|{{main|Polyakov action}} A modification of the Nambu–Goto action for strings that eliminates the square root.}}

{{term|PQ}}
{{defn|Peccei–Quinn, as in [[Peccei–Quinn theory]].}}

{{term|pQCD}}
{{term|PQCD}}
{{defn|Perturbative [[quantum chromodynamics]].}}

{{term|prepotential}}
{{defn|A function used to construct the vector superfield in [[supersymmetric gauge theory]] and [[Seiberg–Witten theory]].}}

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

{{term|Princeton string quartet}}
{{defn|[[David Gross]], [[Jeffrey A. Harvey|Jeffrey Harvey]], [[Emil Martinec]], and [[Ryan Rohm]], who introduced the [[heterotic string]] in 1985.}}

{{term|PSL}}
{{defn|[[Projective special linear group]].}}

{{glossary end}}

==Q==

{{glossary}}

{{term|q}}
{{defn|A [[quark]].}}

{{term|Q}}
{{defn|no=1|The [[BRST operator]].}}
{{defn|no=2|A charge}}
{{defn|no=3|One of the fermionic generators of a [[supersymmetry algebra]].}}

{{term|quark}}
{{defn|{{main|quark}} A strongly interacting elementary particle of spin 1/2.}}

{{term|QCD}}
{{defn|{{main|Quantum chromodynamics}} }}

{{term|QED}}
{{defn|{{main|Quantum electrodynamics}} }}

{{glossary end}}

==R==

{{glossary}}

{{term|R}}
{{defn|no=1|Short for Ramond, as in [[Ramond sector]].}}
{{defn|no=2| A curvature tensor {{main|Scalar curvature|Ricci curvature|Riemann curvature}}}}
{{defn|no=3|An abbreviation for right (moving modes).}}
{{defn|no=4|A radius}}
{{defn|no=5|'''R-symmetry''' is a symmetry of [[extended supersymmetry]] algebras.}}

{{term|Ramond}}
{{defn|Named for [[Pierre Ramond]].}}

{{term|Ramond algebra}}
{{defn|{{main|Ramond algebra}} A supersymmetric extension of the [[Virasoro algebra]], similar to the [[Neveu–Schwarz algebra]].}}

{{term|Rarita–Schwinger}}
{{defn|{{main|Rarita–Schwinger equation|Rarita–Schwinger field}} Refers to spin 3/2 fermions.}}

{{term|Regge}}
{{defn|no=1|Physicist [[Tullio Regge]].}}
{{defn|no=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'''.}}

{{term|revolution}}
{{defn|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-brane]]s, [[M-theory]], and matrix theory and the [[AdS/CFT correspondence]].}}

{{term|RG}}
{{defn|[[Renormalization group]].}}

{{term|RGE}}
{{defn|[[Renormalization group]] equation.}}

{{term|RH}}
{{defn|Right-handed}}

{{term|R–NS}}
{{defn|A sector with Ramond conditions on left moving modes and Neveu–Schwarz conditions on right moving modes.}}

{{term|RNS}}
{{defn|Ramond–Neveu–Schwarz, as in [[RNS formalism]], a way of incorporating supersymmetry into string theory that is supersymmetric on the world sheet.}}

{{term|R-parity}}
{{defn|{{main|R-parity}} A '''Z'''<sub>2</sub> symmetry of supersymmetric models.}}

{{term|R-R}}
{{defn|Short for [[Ramond–Ramond sector]]}}

{{glossary end}}

==S==

{{glossary}}

{{term|s}}
{{defn|no=1|A [[strange quark]].}}
{{defn|no=2|A [[Mandelstam variable]]}}

{{term|S}}
{{defn|no=1|An action}}
{{defn|no=2|A [[scattering matrix]].}}
{{defn|no=3|The transformation τ → –1/τ of the upper half plane}}
{{defn|no=4|Scalar (current)}}
{{defn|no=5|Short for [[supersymmetric|super]] or [[supersymmetric]]}}

{{term|S-brane}}
{{defn|A brane similar to a D-brane, with Dirichlet boundary conditions in the time direction.}}

{{term|S-duality}}
{{defn|{{main|S-duality}} Strong–weak duality, a [[string duality]] relating theories with a large coupling constant to theories with a small coupling constant}}

{{term|SBB}}
{{defn|Standard [[Big Bang]] model of the universe}}

{{term|SCFT}}
{{defn|[[Superconformal field theory]], a supersymmetric extension of conformal field theory}}

{{term|Schwarz}}
{{defn|Named for [[John Henry Schwarz]]}}

{{term|Seiberg duality}}
{{defn|{{main|Seiberg duality}} }}

{{term|SGA}}
{{defn|Abbreviation for [[Spectrum-generating algebra]]}}

{{term|short supermultiplet}}
{{defn|A supermultiplet (representation) related to [[BPS state]]s}}

{{term|sigma model}}
{{defn|{{main|Sigma model|Non-linear sigma model}} A classical or quantum model based on the maps from a base manifold to a target manifold.}}

{{term|SL}}
{{defn|[[Special linear group]]}}

{{term|SLAC}}
{{defn|[[Stanford Linear Accelerator Center]]}}

{{term|SLC}}
{{defn|[[Stanford Linear Collider]]}}

{{term|slepton}}
{{defn|{{main|slepton}} Hypothetical supersymmetric partner of a lepton}}

{{term|SM}}
{{defn|{{main|Standard Model}} }}

{{term|sneutrino}}
{{defn|{{main|sneutrino}} Hypothetical supersymmetric partner of a neutrino}}

{{term|SO}}
{{defn|[[Special orthogonal group]]}}

{{term|Sp}}
{{defn|[[Symplectic group]]}}

{{term|sphaleron}}
{{defn|{{main|Sphaleron}} Static solution to the electroweak field equations}}

{{term|squark}}
{{defn|{{main|squark}} Supersymmetric partner of a quark.}}

{{term|SSB}}
{{defn|[[Spontaneous symmetry breaking]]}}

{{term|SSM}}
{{defn|[[Standard solar model]]}}

{{term|stress–energy tensor}}
{{defn|Alternative name for the [[#energy–momentum tensor]].}}

{{term|string field theory}}
{{defn|{{main|string field theory}} }}

{{term|SU}}
{{defn|[[Special unitary group]]}}

{{term|SUGRA}}
{{defn|Short for [[supergravity]]}}

{{term|superconformal algebra}}
{{defn|{{main|Neveu–Schwarz algebra|Ramond algebra}} A supersymmetric analogue of the Virasoro algebra of conformal symmetries in 2 dimensions}}

{{term|superfield}}
{{defn|{{main|Superfield}} A supersymmetric analogue of a quantum or classical field}}

{{term|supergravity}}
{{defn|{{main|supergravity}} A supersymmetric extension of general relativity}}

{{term|supermultiplet}}
{{defn|{{main|Supermultiplet}} A representation of a [[supersymmetry algebra]]}}

{{term|superpotential}}
{{defn|{{main|Superpotential}} A function of chiral superfield not depending on their superderivatives or spacetime derivatives, used to form a Lagrangian.}}

{{term|superspace}}
{{defn|{{main|superspace}} A supersymmetric analogue of spacetime}}

{{term|superstring}}
{{defn|{{main|superstring}} A supersymmetric analogue of a string}}

{{term|supersymmetry}}
{{defn|{{main|supersymmetry|supersymmetry algebra}} A generalization of a [[Lie superalgebra]], where the Lie bracket [''a'',''b''] is sometimes given by ''ab''+''ba'' rather than ''ab''–''ba''.}}

{{term|SUSY}}
{{defn|An abbreviation for [[supersymmetry]].}}

{{term|SYM}}
{{defn|Supersymmetric Yang–Mills}}

{{glossary end}}

==T==

{{glossary}}

{{term|t}}
{{defn|no=1|A [[top quark]].}}
{{defn|no=2|A [[Mandelstam variable]].}}
{{defn|no=3|Time.}}

{{term|T}}
{{defn|no=1|The [[energy–momentum tensor]].}}
{{defn|no=2|Time, especially the [[time reversal symmetry|time symmetry]].}}
{{defn|no=3|The transformation τ → τ+1 of the upper half plane.}}
{{defn|no=4|A torus.}}
{{defn|no=5|The string tension.}}
{{defn|no=6|Temperature.}}
{{defn|no=7|Tensor (current)}}

{{term|T-duality}}
{{defn|{{main|T-duality}} A [[string duality]] relating theories on a large spacetime to theories on a small spacetime. In particular it exchanges type IIA and IIB superstring theory.}}

{{term|tachyon}}
{{defn|{{main|Tachyon}} A particle of imaginary mass moving faster than light.}}

{{term|ToE}}
{{term|TOE}}
{{defn|[[Theory of everything]]}}

{{term|type I}}
{{term|type II}}
{{term|type IIA}}
{{term|type IIB}}
{{defn|1={{main|Type I string theory}} {{main|Type II string theory}} A type of superstring or the corresponding low-energy supergravity theory. The Roman numeral I or II refers to the number of ''d''=10 supersymmetries, and types IIA or IIB are distinguished by whether the supersymmetries of left and right movers have opposite or identical chiralities.}}

{{glossary end}}

==U==

{{glossary}}

{{term|u}}
{{defn|no=1|An [[up quark]].}}
{{defn|no=2|A [[Mandelstam variable]].}}

{{term|U}}
{{defn|A [[unitary group]].}}

{{term|U-duality}}
{{defn|{{main|U-duality}} Short for "unified duality". A [[string duality]] relating two different string theories.}}

{{term|UED}}
{{defn|Universal extra dimensions}}

{{term|UV}}
{{defn|Short for ultra-violet, often referring to short-distance singularities.}}

{{glossary end}}

==V==

{{glossary}}

{{term|V}}
{{defn|no=1|A [[vertex operator]].}}
{{defn|no=2|Vector (current)}}

{{term|V-A}}
{{defn|Vector-Axial vector }}

{{term|vector superfield}}
{{defn|A type of [[superfield]] related to [[vector supermultiplet]]s.}}

{{term|VEV}}
{{defn|[[Vacuum expectation value]] of an operator.}}

{{term|vielbein}}
{{defn|A frame}}

{{term|vierbein}}
{{defn|A frame in 4 dimensions. Sometimes used for a frame in an arbitrary number of dimension by authors who do not care that "vier" means four in German.}}

{{term|Veneziano amplitude}}
{{defn|{{main|Veneziano amplitude}} The [[Euler beta function]] interpreted as a scattering amplitude.}}

{{term|vertex operator}}
{{defn|{{main|vertex operator}} }}

{{term|Virasoro algebra}}
{{defn|{{main|Virasoro algebra}} A central extension of the [[Witt algebra]] of polynomial vector fields on a circle.}}

{{glossary end}}

==W==

{{glossary}}

{{term|w}}
{{defn|A complex number}}

{{term|W}}
{{defn|A [[W-boson]]}}

{{term|W-algebra}}
{{defn|{{main|W-algebra}} A sort of generalization of the Virasoro algebra}}

{{term|Weyl}}
{{defn|no=1|Named after [[Hermann Weyl]]}}
{{defn|no=2|A [[Weyl transformation]] is a rescaling of the world-sheet metric.}}
{{defn|no=3|[[Weyl spinor]], an element of a half-spin representation in even spacetime dimensions.}}

{{term|WIMP}}
{{defn|[[Weakly interacting massive particle]]}}

{{term|wino }}
{{defn|{{main|wino (particle)}} A hypothetical supersymmetric partner of the [[W-boson]].}}

{{term|Witten}}
{{defn|Named for [[Edward Witten]].}}

{{term|WMAP}}
{{defn|[[Wilkinson Microwave Anisotropy Probe]]}}

{{term|world sheet}}
{{defn|The 2-dimensional subset of spacetime swept out by a moving string.}}

{{term|world-volume}}
{{defn|The ''p''+1-dimensional spacetime volume swept out by a ''p''-brane, as in world-volume action.}}

{{term|WZNW}}
{{term|WZW}}
{{defn|Initials of Wess, Zumino, (Novikov), and Witten, as in the [[WZW model]], a σ-model with a group as the target space.}}

{{glossary end}}

==XYZ==

{{glossary}}

{{term|x}}
{{defn|A real number}}

{{term|X}}
{{defn|Used for coordinates in Minkowski space.}}

{{term|y}}
{{defn|A real number}}

{{term|YBE}}
{{defn|[[Yang–Baxter equation]]}}

{{term|YM}}
{{defn|[[Yang–Mills]]}}

{{term|z}}
{{defn|A complex number}}

{{term|Z}}
{{defn|no=1|A partition function}}
{{defn|no=2|The [[Z boson]].}}
{{defn|An element of the center of an [[extended supersymmetry algebra]].}}

{{term|ZEUS}}
{{defn|{{main|ZEUS (particle detector)}}}}

{{term|zino}}
{{defn|{{main|gaugino}} A hypothetical supersymmetric partner of the Z-boson.}}

{{term|zweibein}}
{{defn|A frame in 2 dimensions}}

{{glossary end}}

==See also==

*[[List of string theory topics]]

==References==

* Becker, Katrin, [[Melanie Becker|Becker, Melanie]], and [[John H. Schwarz]] (2007) ''String Theory and M-Theory: A Modern Introduction ''. Cambridge University Press. {{ISBN|0-521-86069-5}}
* Binétruy, Pierre (2007) ''Supersymmetry: Theory, Experiment, and Cosmology''. Oxford University Press. {{ISBN|978-0-19-850954-7}}.
* Dine, Michael (2007) ''Supersymmetry and String Theory: Beyond the Standard Model''. Cambridge University Press. {{ISBN|0-521-85841-0}}.
*{{Cite book| author=Paul H. Frampton |
title=Dual Resonance Models |
publisher=Frontiers in Physics |
year=1974 | isbn=0-8053-2581-6 |
authorlink=Paul Frampton}}
* [[Michael Green (physicist)|Michael Green]], [[John H. Schwarz]] and [[Edward Witten]] (1987) ''Superstring theory''. Cambridge University Press. The original textbook.
** ''Vol. 1: Introduction''. {{ISBN|0-521-35752-7}}.
** ''Vol. 2: Loop amplitudes, anomalies and phenomenology''. {{ISBN|0-521-35753-5}}.
* Kiritsis, Elias (2007) ''String Theory in a Nutshell''. Princeton University Press. {{ISBN|978-0-691-12230-4}}.
* {{Cite book| first = Clifford | last = Johnson | date = 2003 | title = D-branes | publisher = Cambridge University Press | location = Cambridge | isbn = 0-521-80912-6 }}
* [[Joseph Polchinski|Polchinski, Joseph]] (1998) ''String Theory''. Cambridge University Press.
** ''Vol. 1: An introduction to the bosonic string''. {{ISBN|0-521-63303-6}}.
** ''Vol. 2: Superstring theory and beyond''. {{ISBN|0-521-63304-4}}.
* Szabo, Richard J. (Reprinted 2007) ''An Introduction to String Theory and D-brane Dynamics''. Imperial College Press. {{ISBN|978-1-86094-427-7}}.
* [[Barton Zwiebach|Zwiebach, Barton]] (2004) ''A First Course in String Theory''. Cambridge University Press. {{ISBN|0-521-83143-1}}. Contact author for errata.

==External links==
*[http://www.interactions.org/cms/?pid=1002289 Particle physics glossary at interactions.org] {{Webarchive|url=https://web.archive.org/web/20161123050225/http://www.interactions.org/cms/?pid=1002289 |date=2016-11-23 }}

[[Category:String theory]]
[[Category:Glossaries of science|String theory]]
[[Category:Wikipedia glossaries using description lists]]