Citation: M. Tanabashi et al. (Particle Data Group), Phys. Rev. D 98, 030001 (2018) STRANGE MESONS (S = 1, C = B = 0) K + = us, K 0 = ds, K±0 = d s, K − = u s, similarly for K ∗’s ± P 1 K I (J ) = 2 (0−) Mass m = 493.677 0.016 MeV [a] (S = 2.8) ± Mean life τ = (1.2380 0.0020) 10−8 s (S=1.8) ± × cτ = 3.711 m CPT violation parameters (∆ = rate difference/sum) ∆(K ± µ± ν )=( 0.27 0.21)% → µ − ± ∆(K ± π± π0) = (0.4 0.6)% [b] → ± CP violation parameters (∆ = rate difference/sum) ∆(K ± π± e+ e−)=( 2.2 1.6) 10−2 → − ± × ∆(K ± π± µ+ µ−)=0.010 0.023 → ± ∆(K ± π± π0 γ) = (0.0 1.2) 10−3 → ± × ∆(K ± π± π+ π−) = (0.04 0.06)% → ± ∆(K ± π± π0 π0)=( 0.02 0.28)% → − ± T violation parameters K + π0 µ+ ν P = ( 1.7 2.5) 10−3 → µ T − ± × K + µ+ ν γ P = ( 0.6 1.9) 10−2 → µ T − ± × K + π0 µ+ ν Im(ξ) = 0.006 0.008 → µ − ± Slope parameter g [c] (See Particle Listings for quadratic coefficients and alternative parametrization re- lated to ππ scattering) K ± π± π+ π− g = 0.21134 0.00017 → − ± (g g )/(g + g )=( 1.5 2.2) 10−4 + − − + − − ± × K ± π± π0 π0 g = 0.626 0.007 → ± (g g )/(g + g ) = (1.8 1.8) 10−4 + − − + − ± × K ± decay form factors [d,e] Assuming µ-e universality λ (K + ) = λ (K + ) = (2.97 0.05) 10−2 + µ3 + e3 ± × λ (K + ) = (1.95 0.12) 10−2 0 µ3 ± × HTTP://PDG.LBL.GOV Page1 Created:6/5/201818:58 Citation: M. Tanabashi et al. (Particle Data Group), Phys. Rev. D 98, 030001 (2018) Not assuming µ-e universality λ (K + ) = (2.98 0.05) 10−2 + e3 ± × λ (K + ) = (2.96 0.17) 10−2 + µ3 ± × λ (K + ) = (1.96 0.13) 10−2 0 µ3 ± × Ke3 form factor quadratic fit λ’ (K ± ) linear coeff. = (2.49 0.17) 10−2 + e3 ± × λ′′ (K ± ) quadratic coeff. = (0.19 0.09) 10−2 + e3 ± × K + ¯f /f ¯ = ( 0.3+0.8) 10−2 e3 ¯ S +¯ − −0.7 × K + ¯f /f ¯ = ( 1.2 2.3) 10−2 e3 ¯ T +¯ − ± × K + ¯f /f ¯ = (0.2 0.6) 10−2 µ3 ¯ S +¯ ± × K + ¯f /f ¯ = ( 0.1 0.7) 10−2 µ3 ¯ T +¯ − ± × K + e+ ν γ ¯F + F ¯ = 0.133 0.008 (S= 1.3) → e ¯ A V ¯ ± K + µ+ ν γ ¯F + F ¯ = 0.165 0.013 → µ ¯ A V ¯ ± K + e+ ν γ ¯F F ¯ < 0.49, CL = 90% → e ¯ A − V ¯ K + µ+ ν γ ¯F F ¯ = 0.21 0.06 → µ ¯ A − V ¯ − ± Charge radius ­r® = 0.560 0.031 fm ± Forward-backward asymmetry ± Γ(cos(θK µ)>0)−Γ(cos(θK µ)<0) −2 AFB(K ) = < 2.3 10 , CL = 90% π µµ Γ(cos(θK µ)>0)+Γ(cos(θK µ)<0) × K− modes are charge conjugates of the modes below. Scale factor/ p + K DECAY MODES Fraction (Γi /Γ) Confidence level(MeV/c) Leptonic and semileptonic modes + −5 e νe ( 1.582±0.007) × 10 247 + µ νµ ( 63.56 ±0.11 ) % S=1.2 236 0 + π e νe ( 5.07 ±0.04 ) % S=2.1 228 + Called K e3. 0 + π µ νµ ( 3.352±0.033) % S=1.9 215 + Called K µ3. 0 0 + −5 π π e νe ( 2.55 ±0.04 ) × 10 S=1.1 206 + − + −5 π π e νe ( 4.247±0.024) × 10 203 + − + −5 π π µ νµ ( 1.4 ±0.9 ) × 10 151 0 0 0 + −6 π π π e νe < 3.5 × 10 CL=90% 135 HTTP://PDG.LBL.GOV Page2 Created: 6/5/2018 18:58 Citation: M. Tanabashi et al. (Particle Data Group), Phys. Rev. D 98, 030001 (2018) Hadronic modes π+ π0 ( 20.67 ±0.08 ) % S=1.2 205 π+ π0 π0 ( 1.760±0.023) % S=1.1 133 π+ π+ π− ( 5.583±0.024) % 125 Leptonic and semileptonic modes with photons + −3 µ νµ γ [f,g] ( 6.2 ±0.8 ) × 10 236 + + −5 µ νµ γ (SD ) [d,h] ( 1.33 ±0.22 ) × 10 – + + −5 µ νµ γ (SD INT) [d,h] < 2.7 × 10 CL=90% – + − − −4 µ νµ γ (SD + SD INT) [d,h] < 2.6 × 10 CL=90% – + −6 e νe γ ( 9.4 ±0.4 ) × 10 247 0 + −4 π e νe γ [f,g] ( 2.56 ±0.16 ) × 10 228 0 + −5 π e νe γ (SD) [d,h] < 5.3 × 10 CL=90% 228 0 + −5 π µ νµ γ [f,g] ( 1.25 ±0.25 ) × 10 215 0 0 + −6 π π e νe γ < 5 × 10 CL=90% 206 Hadronic modes with photons or ℓℓ pairs π+ π0 γ (INT) (− 4.2 ±0.9 ) × 10−6 – π+ π0 γ (DE) [f,i] ( 6.0 ±0.4 ) × 10−6 205 + 0 0 f,g +6.0 −6 π π π γ [ ] ( 7.6 −3.0 ) × 10 133 π+ π+ π− γ [f,g] ( 1.04 ±0.31 ) × 10−4 125 π+ γ γ [f ] ( 1.01 ±0.06 ) × 10−6 227 π+ 3γ [f ] < 1.0 × 10−4 CL=90% 227 π+ e+ e− γ ( 1.19 ±0.13 ) × 10−8 227 Leptonic modes with ℓℓ pairs + −5 e νe ν ν < 6 × 10 CL=90% 247 + −6 µ νµ ν ν < 2.4 × 10 CL=90% 236 + + − −8 e νe e e ( 2.48 ±0.20 ) × 10 247 + + − −8 µ νµ e e ( 7.06 ±0.31 ) × 10 236 + + − −8 e νe µ µ ( 1.7 ±0.5 ) × 10 223 + + − −7 µ νµ µ µ < 4.1 × 10 CL=90% 185 Lepton family number (LF ), Lepton number (L), ∆S = ∆Q (SQ) violating modes, or ∆S = 1 weak neutral current (S1) modes + + − −8 π π e νe SQ < 1.3 × 10 CL=90% 203 + + − −6 π π µ νµ SQ < 3.0 × 10 CL=95% 151 π+ e+ e− S1 ( 3.00 ±0.09 ) × 10−7 227 π+ µ+ µ− S1 ( 9.4 ±0.6 ) × 10−8 S=2.6 172 π+ ν ν S1 ( 1.7 ±1.1 ) × 10−10 227 π+ π0 ν ν S1 < 4.3 × 10−5 CL=90% 205 µ− ν e+ e+ LF < 2.1 × 10−8 CL=90% 236 + −3 µ νe LF [j] < 4 × 10 CL=90% 236 HTTP://PDG.LBL.GOV Page3 Created: 6/5/2018 18:58 Citation: M. Tanabashi et al. (Particle Data Group), Phys. Rev. D 98, 030001 (2018) π+ µ+ e− LF < 1.3 × 10−11 CL=90% 214 π+ µ− e+ LF < 5.2 × 10−10 CL=90% 214 π− µ+ e+ L < 5.0 × 10−10 CL=90% 214 π− e+ e+ L < 6.4 × 10−10 CL=90% 227 π− µ+ µ+ L [j] < 8.6 × 10−11 CL=90% 172 + −3 µ νe L [j] < 3.3 × 10 CL=90% 236 0 + −3 π e νe L < 3 × 10 CL=90% 228 π+ γ [k] < 2.3 × 10−9 CL=90% 227 0 P 1 K I (J ) = 2 (0−) 50% KS , 50% KL Mass m = 497.611 0.013 MeV (S = 1.2) ± m 0 m = 3.934 0.020 MeV (S = 1.6) K − K ± ± Mean square charge radius ­r2® = 0.077 0.010 fm2 − ± T-violation parameters in K 0-K 0 mixing [e] Asymmetry A in K 0-K 0 mixing = (6.6 1.6) 10−3 T ± × CP-violation parameters Re(ǫ) = (1.596 0.013) 10−3 ± × CPT-violation parameters [e] Re δ = (2.5 2.3) 10−4 ± × Im δ = ( 1.5 1.6) 10−5 − ± × −3 Re(y), Ke3 parameter = (0.4 2.5) 10 ± × −3 Re(x−), Ke3 parameter = ( 2.9 2.0) 10 − ± −19× [l] ¯m 0 m 0 ¯ / m < 6 10 , CL = 90% ¯ K − K ¯ average × (Γ Γ )/m = (8 8) 10−18 K 0 − K 0 average ± × Tests of ∆S = ∆Q Re(x ), K parameter = ( 0.9 3.0) 10−3 + e3 − ± × K 0 P 1 S I (J ) = 2 (0−) Mean life τ = (0.8954 0.0004) 10−10 s (S = 1.1) Assum- ± × ing CPT Mean life τ = (0.89564 0.00033) 10−10 s Not assuming ± × CPT cτ = 2.6844 cm Assuming CPT HTTP://PDG.LBL.GOV Page4 Created: 6/5/2018 18:58 Citation: M. Tanabashi et al. (Particle Data Group), Phys. Rev. D 98, 030001 (2018) CP-violation parameters [n] Im(η ) = 0.002 0.009 +−0 − ± Im(η ) = 0.001 0.016 000 − ± ¯η ¯ = ¯A(K 0 3π0)/A(K 0 3π0)¯ < 0.0088, CL = ¯ 000¯ ¯ S → L → ¯ 90% CP asymmetry A in π+ π− e+ e− = ( 0.4 0.8)% − ± Scale factor/ p K0 DECAY MODES c S DECAY MODES Fraction (Γi /Γ) Confidence level (MeV/ ) Hadronic modes π0 π0 (30.69±0.05) % 209 π+ π− (69.20±0.05) % 206 + − 0 . +1.1 × −7 π π π ( 3 5 −0.9 ) 10 133 Modes with photons or ℓℓ pairs π+ π− γ [g,o] ( 1.79±0.05) × 10−3 206 π+ π− e+ e− ( 4.79±0.15) × 10−5 206 π0 γ γ [o] ( 4.9 ±1.8 ) × 10−8 230 γ γ ( 2.63±0.17) × 10−6 S=3.0 249 Semileptonic modes ± ∓ −4 π e νe [p] ( 7.04±0.08) × 10 229 CP violating (CP) and ∆S = 1 weak neutral current (S1) modes 3π0 CP < 2.6 × 10−8 CL=90% 139 µ+ µ− S1 < 8 × 10−10 CL=90% 225 e+ e− S1 < 9 × 10−9 CL=90% 249 0 + − S1 o .