STRANGE MESONS
($\boldsymbol S$ = $\pm1$, $\boldsymbol C$ = $\boldsymbol B$ = 0)
${{\mathit K}^{+}}$ = ${\mathit {\mathit u}}$ ${\mathit {\overline{\mathit s}}}$, ${{\mathit K}^{0}}$ = ${\mathit {\mathit d}}$ ${\mathit {\overline{\mathit s}}}$, ${{\overline{\mathit K}}^{0}}$ = ${\mathit {\overline{\mathit d}}}$ ${\mathit {\mathit s}}$, ${{\mathit K}^{-}}$ = ${\mathit {\overline{\mathit u}}}$ ${\mathit {\mathit s}}$, similarly for ${{\mathit K}^{*}}$'s

INSPIRE search

${{\boldsymbol K}_L^0}$ $I(J^P)$ = $1/2(0^{-})$

See related reviews:
$\mathit V_{{\mathit {\mathit u}}{\mathit {\mathit d}}}$, $\mathit V_{{\mathit {\mathit u}}{\mathit {\mathit s}}}$ the Cabibbo Angle, and CKM Unitarity

$\mathit CP$ Violation in ${{\mathit K}_L^0}$ Decays

$\Delta \mathit S$ = $\Delta \mathit Q$ in ${{\mathit K}^{0}}$ Decays

${\mathit m}_{{{\mathit K}_L^0} }–{\mathit m}_{{{\mathit K}_S^0} }$

$(52.93 \pm0.09) \times 10^{8}$ $\hbar{}$ s${}^{-1}$ (S = 1.3)

${{\mathit K}_L^0}$ MEAN LIFE

$(5.116 \pm0.021) \times 10^{-8}$ s (S = 1.1)

▸	ENERGY DEPENDENCE OF ${{\boldsymbol K}_L^0}$ DALITZ PLOT

▸	${{\boldsymbol K}_L^0}$ FORM FACTORS

▸	$\boldsymbol CP$-VIOLATION PARAMETERS IN ${{\boldsymbol K}_L^0}$ DECAYS

▸	PARAMETERS for ${{\boldsymbol K}_L^0}$ $\rightarrow$ ${{\boldsymbol \pi}^{+}}{{\boldsymbol \pi}^{-}}{{\boldsymbol \gamma}}$ DECAY

$\boldsymbol T$ VIOLATION TESTS IN ${{\boldsymbol K}_L^0}$ DECAYS

Im($\xi $) in ${{\mathit K}_{{\mu3}}^{0}}$ DECAY (from transverse ${{\mathit \mu}}$ pol.)

$-0.007 \pm0.026$

▸	$\boldsymbol CPT$-INVARIANCE TESTS IN ${{\boldsymbol K}_L^0}$ DECAYS

Re(${2\over 3}\eta _{+−}$ $+$ ${1\over 3}\eta _{00})−{\mathit A_{L}\over 2}$

$(-0.3 \pm3.5) \times 10^{-5}$

▸

$\boldsymbol x$ = A( ${{\overline{\boldsymbol K}}^{0}}$ $\rightarrow$ ${{\boldsymbol \pi}^{-}}{{\boldsymbol \ell}^{+}}{{\boldsymbol \nu}}$ )/A( ${{\boldsymbol K}^{0}}$ $\rightarrow$ ${{\boldsymbol \pi}^{-}}{{\boldsymbol \ell}^{+}}{{\boldsymbol \nu}}$ ) = A($\Delta \boldsymbol S=−\Delta \boldsymbol Q)/A(\Delta \boldsymbol S=\Delta \boldsymbol Q$)

Decay Modes ▸ Expand all decays

▸	Semileptonic modes

▸	Hadronic modes, including Charge conjugation${\times }$Parity Violating ($\mathit CPV$) modes

▸	Semileptonic modes with photons

▸	Hadronic modes with photons or ${{\mathit \ell}}{{\overline{\mathit \ell}}}$ pairs

▸	Other modes with photons or ${{\mathit \ell}}{{\overline{\mathit \ell}}}$ pairs

▸	Charge conjugation ${\times }$ Parity ($\mathit CP$) or Lepton Family number ($\mathit LF$) violating modes, or $\Delta \mathit S$ = 1 weak neutral current ($\mathit S1$) modes

constrained fit information