BOTTOM MESONS(B=±1)B^+=u,B^0=d,B^0=db,B^-=b,similarly for B~*'s

Many measurements of B decays involve admixtures of B hadrons. Previously we arbitrarily included such admixtures in the B±section, but because of their importance we have created two new sections：

N BARYONS(S=0,I=1/2)p,N^+=uud;n,N^0=udd

p MASS （atomic mass units u）The mass is known much more precisely in u （atomic mass units） than in MeV. See the next data block.

BOTTOM,CHARMED MESONS(B=C=±1)B_c^+=c,B_c^-=cb,similarly for B_c~*'s

I（JP） = 0（0-）I, J, P need confirmation.Quantum numbers shown are quark-model predictions.

REVIEW OF PARTICLE PHYSICS

The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,283 new measurements from 899 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as heavy neutrinos, supersymmetric and technicolor particles, axions, dark photons, etc. 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 Supersymmetry, Extra Dimensions, Particle Detectors, Probability, and Statistics. Among the 112 reviews are many that are new or heavily revised including those on： Dark Energy, Higgs Boson Physics, Electroweak Model, Neutrino Cross Section Measurements, Monte Carlo Neutrino Generators, Top Quark, Dark Matter, Dynamical Electroweak Symmetry Breaking, Accelerator Physics of Colliders, High-Energy Collider Parameters, Big Bang Nucleosynthesis, Astrophysical Constants and Cosmological Parameters. 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.

Measurement of the integrated luminosity of the Phase 2 data of the Belle Ⅱ experiment

From April to July 2018,a data sample at the peak energy of the T(4 S) resonance was collected with the Belle Ⅱ detector at the SuperKEKB electron-positron collider.This is the first data sample of the Belle Ⅱ experiment.Using Bhabha and digamma events,we measure the integrated luminosity of the data sample to be(496.3±0.3±3.0) pb-1,where the first uncertainty is statistical and the second is systematic.This work provides a basis for future luminosity measurements at Belle Ⅱ.

CHARMED BARYONS(C=+1)∧_c^+=udc,∑_c^(++)=uuc,∑_c^+=udc,∑_c^0=ddc,≡_c^+=usc,≡_c^0=dsc,Ω_c^0=ssc

CHARMED BARYONS Revised March 2012 by C.G. Wohl （LBNL）. There are 17 known charmed baryons, and four other candidates not well enough established to be promoted to the Summary Tables.＊ Fig. l（a） shows the mass spectrum,

PARTICLE DETECTORS AT ACCELERATORS

33.1. Introduction This review summarizes the detector technologies employed at accelerator particle physics experiments. Several of these detectors are also used in a non-accelerator context and examples of such applications will be provided. The detector techniques which are specific to non-accelerator particle physics experiments are the subject of Chap.

KINEMATICS

Revised January 2000 by J.D. Jackson （LBNL） and June 2008 by D.R. Tovey （Sheffield）.

INTRODUCTION

1. Overview The Review of Particle Physics and the abbreviated version, the Particle Physics Booklet, are reviews of the field of Particle Physics. This complete Review includes a compilation/evaluation of data on particle properties, called the ＂Particle Listings.＂ These Listings include 3,283 new measurements from 899 papers, in addition to the 32,153 measurements from 8,944 papers that first appeared in previous editions [1].

BOTTOM BARYONS(B=-1)∧_b^0=udb,≡_b^0=usb,≡_b^-=dsb,Ω_b^-=ssb

In the quark model, a ∧b0 is an isospin-0 udb state. The lowest ∧b0 ought to have JP = 1/2＋. None of I, J, or P have actually been measured.

∧ BARYONS(S=-1,I=0)∧~0=uds

We have omitted some results that have been superseded by later experiments. See our earlier editions.

SU(3) ISOSCALAR FACTORS AND REPRESENTATION MATRICES

Written by R.L. Kelly （LBNL）. The most commonly used SU（3） isoscalar factors, corresponding to the singlet, octet, and deeuplet content of 8 8 and 10 8, are shown at the right. The notation uses particle names to identify the coefficients, so that the pattern of relative couplings may be seen at a glance. We illustrate the use of the coefficients below.

QUARKS

QUARK MASSESUpdated Jan 2014 by A.V. Manohar （University of California, San Diego） and C.T. Sachrajda （University of Southampton）

ELECTROWEAK MODEL AND CONSTRAINTS ON NEW PHYSICS

Revised November 2013 by J. Erler （U. Mexico） and A. Freit＆s （Pittsburgh U.）.10.1 Introduction 10.2 Renormalization and radiative corrections

ACCELERATOR PHYSICS OF COLLIDERS

Revised August 2013 by M.J. Syphers （MSU） and F. Zimmermann （CERN）.29.1. Luminosity This article provides background for the High-Energy Collider Parameter Tables that follow. The number of events, Nexp, is the product of the cross section of interest,

CLEBSCH-GORDAN COEFFICIENTS,SPHERICAL HARMONICS,AND d FUNCTIONS

Note： A square-root sign is to be understood over every coefficient, e.g., for -8/15 read - √8√15.

QUARK MODEL

Revised August 2013 by C. Amsler （University of Bern）, T. DeGrand （University of Colorado, Boulder）, and B. Krusche （University of Basel）.

BIG-BANG COSMOLOGY

Revised September 2013 by K.A. Olive （University of Minnesota） and J.A. Peacock （University of Edinburgh）.

COSMIC RAYS

Revised October 2013 by J.J. Beatty （Ohio State Univ.）, J. Matthews （Louisiana State Univ.）, and S.P. Wakely （Univ. of Chicago）; revised August 2009 by T.K. Gaisser and T. Stanev （Bartol Research Inst., Univ. of Delaware）.

STATISTICS

Revised September 2013 by G. Cowan （RHUL）. This chapter gives an overview of statistical methods used in high-energy physics. In statistics, we are interested in using a given sample of data to make inferences about a probabilistic model, e.g., to assess the model＇s validity or to determine the values of its parameters. There are two main approaches to statistical inference, which we may call frequentist and Bayesian.