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Particle Physics Data

Fundamental particle masses, lifetimes, charges, coupling constants, decay modes, and mixing parameters — drawn from PDG 2022 and CODATA 2018.

Source: PDG 2022 Review of Particle Physics; CODATA 2018

Charged Leptons

Electron (e⁻)

Mass	0.510 998 950 00 ± 0.000 000 000 15	MeV/c²
Mass	9.109 383 7015 × 10⁻³¹ ± 0.000 000 0028 × 10⁻³¹	kg
Charge	−1	e	exact
Spin	1/2	ℏ	exact
Magnetic moment (g-factor)	−2.002 319 304 360 92 ± 0.000 000 000 000 36
Mean lifetime	> 6.6 × 10²⁸	yr	lower bound
Lepton number L_e	+1		exact

Muon (μ⁻)

Mass	105.658 375 5 ± 0.000 002 3	MeV/c²
Mass (in electron masses)	206.768 2830 ± 0.000 0046	mₑ
Charge	−1	e	exact
Spin	1/2	ℏ	exact
Mean lifetime	2.196 981 1 ± 0.000 002 2	μs
Anomalous magnetic moment aμ = (g−2)/2	0.001 165 920 89 ± 0.000 000 000 63
Lepton number L_μ	+1		exact

Tau (τ⁻)

Mass	1776.86 ± 0.12	MeV/c²
Charge	−1	e	exact
Spin	1/2	ℏ	exact
Mean lifetime	(290.3 ± 0.5) × 10⁻¹⁵	s
Lepton number L_τ	+1		exact

Neutrinos

νₑ (electron neutrino)

Mass	< 1.1	eV/c²	upper bound
Charge	0	e	exact
Spin	1/2	ℏ	exact

νμ (muon neutrino)

Mass	< 0.19	MeV/c²	upper bound
Charge	0	e	exact

ντ (tau neutrino)

Mass	< 18.2	MeV/c²	upper bound
Charge	0	e	exact

Neutrino (lightest mass eigenstate m₁)

Mass	< 0.8	eV/c²	upper bound

Neutrino mass-squared splitting Δm²₂₁

Value	(7.53 ± 0.18) × 10⁻⁵	eV²

Neutrino mass-squared splitting |Δm²₃₁|

Value (normal ordering)	(2.455 ± 0.028) × 10⁻³	eV²

Sum of neutrino masses Σmν

Upper limit (cosmological)	< 0.12	eV/c²	upper bound

Dirac or Majorana?

Nature	Unknown

Quarks

Up quark (u)

Current mass (MS-bar, 2 GeV)	2.16 +0.49/−0.26	MeV/c²
Charge	+2/3	e	exact
Isospin	+1/2		exact
Spin	1/2	ℏ	exact
Baryon number	1/3		exact

Down quark (d)

Current mass (MS-bar, 2 GeV)	4.67 +0.48/−0.17	MeV/c²
Charge	−1/3	e	exact
Isospin	−1/2		exact
Spin	1/2	ℏ	exact

Strange quark (s)

Current mass (MS-bar, 2 GeV)	93 +11/−5	MeV/c²
Charge	−1/3	e	exact
Strangeness	−1		exact
Spin	1/2	ℏ	exact

Charm quark (c)

Current mass (MS-bar, mc)	1.27 ± 0.02	GeV/c²
Charge	+2/3	e	exact
Charm number	+1		exact
Spin	1/2	ℏ	exact

Bottom quark (b)

Current mass (MS-bar, mb)	4.180 +0.030/−0.020	GeV/c²
Charge	−1/3	e	exact
Bottomness	−1		exact
Spin	1/2	ℏ	exact

Top quark (t)

Pole mass	172.69 ± 0.30	GeV/c²
MS-bar mass mt(mt)	162.5 +2.1/−1.5	GeV/c²
Charge	+2/3	e	exact
Topness	+1		exact
Spin	1/2	ℏ	exact
Total decay width	1.42 +0.19/−0.15	GeV
Dominant decay	t → Wb (branching ratio ≈ 1)

Gauge Bosons

Photon (γ)

Mass	< 1 × 10⁻¹⁸	eV/c²	upper bound
Charge	0	e	exact
Spin	1	ℏ	exact
Mean lifetime	Stable		exact

W boson (W±)

Mass	80.377 ± 0.012	GeV/c²
Charge	±1	e	exact
Spin	1	ℏ	exact
Total decay width	2.085 ± 0.042	GeV
Leptonic branching ratio (per flavor)	10.86 ± 0.09	%
Hadronic branching ratio	67.41 ± 0.27	%

Z boson (Z⁰)

Mass	91.1876 ± 0.0021	GeV/c²
Charge	0	e	exact
Spin	1	ℏ	exact
Total decay width	2.4952 ± 0.0023	GeV
Hadronic partial width	1744.4 ± 2.0	MeV
Invisible partial width	499.0 ± 1.5	MeV
Number of light ν generations (from Z width)	2.9840 ± 0.0082

Gluon (g)

Mass	0 (theoretical; confinement prevents free propagation)		theory
Charge	0	e	exact
Spin	1	ℏ	exact
Color charge	Octet (8 states)		exact

Higgs Boson

Higgs boson (H⁰)

Mass	125.25 ± 0.17	GeV/c²
Charge	0	e	exact
Spin	0	ℏ	exact
CP eigenvalue	+1 (even)
Total decay width	3.2 +2.4/−1.7	MeV
BR(H → bb̄)	58.2 ± 0.6	%
BR(H → WW*)	21.4 ± 0.3	%
BR(H → ττ)	6.27 ± 0.10	%
BR(H → ZZ*)	2.62 ± 0.04	%
BR(H → γγ)	0.228 ± 0.004	%
BR(H → μμ)	0.022 ± 0.001	%
VEV (vacuum expectation value) v	246.220 ± 0.001	GeV
Discovery	LHC (ATLAS + CMS), 4 July 2012

Coupling Constants & Mixing Angles

Fine structure constant α (Q = 0)

Value	1 / 137.035 999 084 ± 0.000 000 021

Fine structure constant α (Q = mZ)

Value	1 / 127.951 ± 0.009

Strong coupling αs(mZ) (MS-bar)

Value	0.1179 ± 0.0010

Fermi coupling constant GF

Value	1.166 378 7 × 10⁻⁵ ± 0.000 000 6 × 10⁻⁵	GeV⁻²

Weak mixing angle sin²θW (on-shell)

Value	0.222 90 ± 0.000 30

Weak mixing angle sin²θW (MS-bar, mZ)

Value	0.231 21 ± 0.000 04

Electroweak mixing angle θW

sin²θW	0.231 21 ± 0.000 04

SU(2) gauge coupling g

Value at mZ	0.6520 ± 0.0002

U(1) gauge coupling g′

Value at mZ	0.3574 ± 0.0001

QCD scale ΛQCD (MS-bar, Nf=5)

Value	210 +30/−25	MeV

CP-violation parameter (kaon sector) ε_K

Magnitude	(2.228 ± 0.011) × 10⁻³

CP-violation parameter (B sector) sin2β

Value	0.699 ± 0.017

CKM Matrix Elements

CKM matrix Vud

Magnitude	0.974 38 ± 0.000 14

CKM matrix Vus

Magnitude	0.224 93 ± 0.000 08

CKM matrix Vub

Magnitude	(3.82 ± 0.24) × 10⁻³

CKM matrix Vcd

Magnitude	0.225 0 ± 0.000 6

CKM matrix Vcs

Magnitude	0.974 5 ± 0.000 6

CKM matrix Vcb

Magnitude	(40.8 ± 1.4) × 10⁻³

CKM matrix Vtd

Magnitude	(8.60 ± 0.42) × 10⁻³

CKM matrix Vts

Magnitude	(40.3 ± 1.8) × 10⁻³

CKM matrix Vtb

Magnitude	0.999 05 +0.000 32/−0.000 34

Wolfenstein parameter λ

Value	0.225 37 ± 0.000 61

Wolfenstein parameter A

Value	0.804 +0.016/−0.020

Wolfenstein parameter ρ̄

Value	0.132 +0.023/−0.014

Wolfenstein parameter η̄

Value	0.350 ± 0.012

CKM CP-violating phase δ₁₃

Value	(65.7 +1.4/−2.5)°

Jarlskog invariant J

Value	(3.08 ± 0.15) × 10⁻⁵

PMNS Neutrino Mixing

PMNS angle θ₁₂ (solar)

sin²θ₁₂	0.307 ± 0.013
θ₁₂	33.44 +0.77/−0.74	°

PMNS angle θ₂₃ (atmospheric, normal ordering)

sin²θ₂₃	0.546 ± 0.021

PMNS angle θ₂₃ (atmospheric)

θ₂₃	47.7 +1.2/−5.8	°

PMNS angle θ₁₃ (reactor)

sin²θ₁₃	0.022 19 ± 0.000 69
θ₁₃	8.57 +0.13/−0.12	°

CP-violating phase δCP

Value (normal ordering)	195 +52/−25	°

Mass ordering

Current status	Normal ordering preferred; inverted not ruled out

Selected Baryons & Nucleons

Proton (p)

Mass	938.272 046 13 ± 0.000 000 38	MeV/c²
Charge	+1	e	exact
Spin	1/2	ℏ	exact
Magnetic moment μp	2.792 847 344 62 ± 0.000 000 000 82	μN
Mean lifetime	> 3.6 × 10²⁹	yr	lower bound
Charge radius rp	0.8414 ± 0.0019	fm

Neutron (n)

Mass	939.565 420 52 ± 0.000 000 54	MeV/c²
Charge	0	e	exact
Spin	1/2	ℏ	exact
Mean lifetime (free)	878.4 ± 0.5	s
Magnetic moment μn	−1.913 042 76 ± 0.000 000 45	μN
Electric dipole moment dn	< 1.8 × 10⁻²⁶	e·cm	upper bound

Proton–neutron mass difference

mn − mp	1.293 332 36 ± 0.000 000 73	MeV/c²

Lambda (Λ⁰)

Mass	1115.683 ± 0.006	MeV/c²
Mean lifetime	(263.2 ± 2.0) × 10⁻¹²	s

Sigma (Σ⁺)

Mass	1189.37 ± 0.07	MeV/c²
Mean lifetime	(80.18 ± 0.26) × 10⁻¹²	s

Xi (Ξ⁻)

Mass	1321.71 ± 0.07	MeV/c²
Mean lifetime	(163.9 ± 1.5) × 10⁻¹²	s

Omega (Ω⁻)

Mass	1672.45 ± 0.29	MeV/c²
Mean lifetime	(82.1 ± 1.1) × 10⁻¹²	s

Delta (Δ⁺⁺)

Mass	1232 ± 2	MeV/c²
Width	117 ± 3	MeV

Selected Mesons

Neutral pion (π⁰)

Mass	134.976 6 ± 0.000 6	MeV/c²
Mean lifetime	(8.46 ± 0.14) × 10⁻¹⁷	s
Dominant decay	π⁰ → γγ (BR ≈ 98.8%)

Charged pion (π±)

Mass	139.570 39 ± 0.000 18	MeV/c²
Mean lifetime	(26.033 ± 0.005) × 10⁻⁹	s
Dominant decay	π± → μ± + νμ (BR ≈ 99.99%)

Kaon (K±)

Mass	493.677 ± 0.016	MeV/c²
Mean lifetime	(12.380 ± 0.020) × 10⁻⁹	s

Kaon (KS⁰)

Mass	497.611 ± 0.013	MeV/c²
Mean lifetime	(89.54 ± 0.04) × 10⁻¹²	s

Kaon (KL⁰)

Mean lifetime	(51.16 ± 0.21) × 10⁻⁹	s

Eta meson (η)

Mass	547.862 ± 0.017	MeV/c²

Rho meson (ρ⁰)

Mass	775.26 ± 0.23	MeV/c²

D meson (D⁰)

Mass	1864.83 ± 0.05	MeV/c²
Mean lifetime	(410.3 ± 1.0) × 10⁻¹⁵	s

B meson (B±)

Mass	5279.34 ± 0.12	MeV/c²
Mean lifetime	(1.638 ± 0.004) × 10⁻¹²	s

J/ψ (cc̄)

Mass	3096.900 ± 0.006	MeV/c²

Υ (bb̄)

Mass	9460.30 ± 0.26	MeV/c²

Key Constants (Particle Context)

Speed of light c

Value	299 792 458	m/s	exact

Planck constant h

Value	6.626 070 15 × 10⁻³⁴	J·s	exact

Reduced Planck constant ℏ

Value	1.054 571 817 × 10⁻³⁴	J·s	exact

Reduced Planck constant ℏc

Value	197.326 980 4 ± 0.000 000 4	MeV·fm

Elementary charge e

Value	1.602 176 634 × 10⁻¹⁹	C	exact

Proton-to-electron mass ratio mp/me

Value	1836.152 673 426 ± 0.000 000 032

Atomic mass unit u

Value	931.494 102 42 ± 0.000 000 28	MeV/c²

Electron volt eV

Value	1.602 176 634 × 10⁻¹⁹	J	exact

Classical electron radius re

Value	2.817 940 326 2 × 10⁻¹⁵ ± 0.000 000 001 3 × 10⁻¹⁵	m

Thomson cross section σT

Value	0.665 245 873 4 × 10⁻²⁸ ± 0.000 000 001 4 × 10⁻²⁸	m²

Bohr magneton μB

Value	9.274 010 0783 × 10⁻²⁴ ± 0.000 000 0028 × 10⁻²⁴	J/T

Nuclear magneton μN

Value	5.050 783 7461 × 10⁻²⁷ ± 0.000 000 0015 × 10⁻²⁷	J/T