This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2658 new measurements from 644 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 112 reviews are many that are new or heavily revised including those on Heavy-Quark and Soft-Collinear Effective Theory, Neutrino Cross Section Measurements, Monte Carlo Event Generators, Lattice QCD, Heavy Quarkonium Spectroscopy, Top Quark, Dark Matter, V-cb & V-ub, Quantum Chromodynamics, High-Energy Collider Parameters, Astrophysical Constants, Cosmological Parameters, and Dark Matter. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov

This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2778 new measurements from 645 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 108 reviews are many that are new or heavily revised including those on CKM quark-mixing matrix, Vud & Vus , Vcb & Vub , top quark, muon anomalous magnetic moment, extra dimensions, particle detectors, cosmic background radiation, dark matter, cosmological parameters, and big bang cosmology. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov

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We show that minimal SO(10) Grand Unification models where the fermions have Yukawa couplings to only one (complex) 10 and one 126 of Higgs scalars lead to a very predictive neutrino spectrum. This comes about since the standard model doublet contained in the 126 of Higgs (needed for the see-saw mechanism) receives an induced vacuum expectation value at tree-level, which, in addition to correcting the bad asymptotic mass relations m d = m e and m s = m µ , also relates the Majorana neutrino mass matrix to observables in the charged fermion sectors. We find that (i) the ν e − ν µ mixing angle relevant for the solar neutrinos can be considerably smaller than the Cabibbo angle and lies in the range sinθ eµ = 0 − 0.3, (ii) ν e − ν τ mixing is sinθ eτ ≃ 3|V td | ≃ 0.05, (iii) the ν µ −ν τ mixing angle is large, sinθ µτ ≃ 3|V cb | = 0.12−0.16, and (iv) m ντ /m νµ ≥ 10 3 , implying that ν µ − ν τ oscillations should be accessible to forthcoming experiments.