BARYON NUMBER

$\Gamma\mathrm {( {{\mathit Z}} \rightarrow {{\mathit p}} {{\mathit \mu}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<1.8\times 10^{-6}$ CL=95.0%
$\Gamma\mathrm {( {{\mathit Z}} \rightarrow {{\mathit p}} {{\mathit e}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<1.8\times 10^{-6}$ CL=95.0%
$\Gamma\mathrm {( {{\mathit \tau}^{-}} \rightarrow {{\overline{\mathit p}}} {{\mathit \mu}^{+}} {{\mathit \mu}^{-}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<3.3\times 10^{-7}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \tau}^{-}} \rightarrow {{\mathit p}} {{\mathit \mu}^{-}} {{\mathit \mu}^{-}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<4.4\times 10^{-7}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \tau}^{-}} \rightarrow {{\overline{\mathit \Lambda}}} {{\mathit \pi}^{-}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<1.4\times 10^{-7}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \tau}^{-}} \rightarrow {{\mathit \Lambda}} {{\mathit \pi}^{-}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<7.2\times 10^{-8}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \tau}^{-}} \rightarrow {{\overline{\mathit p}}} {{\mathit \pi}^{0}} {{\mathit \eta}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<2.7\times 10^{-5}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \tau}^{-}} \rightarrow {{\overline{\mathit p}}}2 {{\mathit \pi}^{0}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<3.3\times 10^{-5}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \tau}^{-}} \rightarrow {{\overline{\mathit p}}} {{\mathit \eta}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<8.9\times 10^{-6}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \tau}^{-}} \rightarrow {{\overline{\mathit p}}} {{\mathit \pi}^{0}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<1.5\times 10^{-5}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \tau}^{-}} \rightarrow {{\overline{\mathit p}}} {{\mathit \gamma}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<3.5\times 10^{-6}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit D}^{0}} \rightarrow {{\overline{\mathit p}}} {{\mathit e}^{+}} )}$ $/$ $\Gamma\mathrm {(total)}$ [1] $<1.1\times 10^{-5}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit D}^{0}} \rightarrow {{\mathit p}} {{\mathit e}^{-}} )}$ $/$ $\Gamma\mathrm {(total)}$ [2] $<1.0\times 10^{-5}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit B}^{+}} \rightarrow {{\overline{\mathit \Lambda}}^{0}} {{\mathit e}^{+}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<8\times 10^{-8}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit B}^{+}} \rightarrow {{\overline{\mathit \Lambda}}^{0}} {{\mathit \mu}^{+}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<6\times 10^{-8}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit B}^{+}} \rightarrow {{\mathit \Lambda}^{0}} {{\mathit e}^{+}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<3.2\times 10^{-8}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit B}^{+}} \rightarrow {{\mathit \Lambda}^{0}} {{\mathit \mu}^{+}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<6\times 10^{-8}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit B}^{0}} \rightarrow {{\mathit \Lambda}_{{c}}^{+}} {{\mathit e}^{-}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<4\times 10^{-6}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit B}^{0}} \rightarrow {{\mathit \Lambda}_{{c}}^{+}} {{\mathit \mu}^{-}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<1.4\times 10^{-6}$ CL=90.0%
${{\mathit p}}$ mean life [3] $>3.6 \times 10^{29}$ years CL=90.0%
$\Gamma\mathrm {( {{\mathit N}} \rightarrow {{\mathit \mu}^{+}} {{\mathit K}} )}$ $/$ $\Gamma\mathrm {(total)}$ $>26$ (${{\mathit n}}$), $>1600$ (${{\mathit p}}$) CL=90.0%
$\Gamma\mathrm {( {{\mathit N}} \rightarrow {{\mathit e}^{+}} {{\mathit K}} )}$ $/$ $\Gamma\mathrm {(total)}$ $>17$ (${{\mathit n}}$), $>1000$ (${{\mathit p}}$) CL=90.0%
$\Gamma\mathrm {( {{\mathit N}} \rightarrow {{\mathit \mu}^{+}} {{\mathit \pi}} )}$ $/$ $\Gamma\mathrm {(total)}$ $>3500$ (${{\mathit n}}$), $>7700$ (${{\mathit p}}$) CL=90.0%
A few examples of proton or bound neutron decay follow. For limits on many other nucleon decay channels, see the Baryon Summary Table.
$\Gamma\mathrm {( {{\mathit N}} \rightarrow {{\mathit e}^{+}} {{\mathit \pi}} )}$ $/$ $\Gamma\mathrm {(total)}$ $>5300$ (${{\mathit n}}$), $>16000$ (${{\mathit p}}$) CL=90.0%
limit on ${{\mathit n}}{{\overline{\mathit n}}}$ oscillations (free ${{\mathit n}}$) $>0.86 \times 10^{8}$ s CL=90.0%
limit on ${{\mathit n}}{{\overline{\mathit n}}}$ oscillations (bound ${{\mathit n}}$) [4] $>2.7 \times 10^{8}$ s CL=90.0%
$\Gamma\mathrm {( {{\mathit \Lambda}} \rightarrow {{\overline{\mathit p}}} {{\mathit \pi}^{+}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<9\times 10^{-7}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \Lambda}} \rightarrow {{\mathit K}_S^0} {{\mathit \nu}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<2\times 10^{-5}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \Lambda}} \rightarrow {{\mathit K}^{-}} {{\mathit \mu}^{+}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<3\times 10^{-6}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \Lambda}} \rightarrow {{\mathit K}^{-}} {{\mathit e}^{+}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<2\times 10^{-6}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \Lambda}} \rightarrow {{\mathit K}^{+}} {{\mathit \mu}^{-}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<3\times 10^{-6}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \Lambda}} \rightarrow {{\mathit K}^{+}} {{\mathit e}^{-}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<2\times 10^{-6}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \Lambda}} \rightarrow {{\mathit \pi}^{-}} {{\mathit \mu}^{+}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<6\times 10^{-7}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \Lambda}} \rightarrow {{\mathit \pi}^{-}} {{\mathit e}^{+}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<4\times 10^{-7}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \Lambda}} \rightarrow {{\mathit \pi}^{+}} {{\mathit \mu}^{-}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<6\times 10^{-7}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \Lambda}} \rightarrow {{\mathit \pi}^{+}} {{\mathit e}^{-}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<6\times 10^{-7}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \Lambda}_{{c}}^{+}} \rightarrow {{\overline{\mathit p}}} {{\mathit e}^{+}} {{\mathit \mu}^{+}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<1.6\times 10^{-5}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \Lambda}_{{c}}^{+}} \rightarrow {{\overline{\mathit p}}}2 {{\mathit \mu}^{+}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<9.4\times 10^{-6}$ CL=90.0%
$\Gamma\mathrm {( {{\mathit \Lambda}_{{c}}^{+}} \rightarrow {{\overline{\mathit p}}}2 {{\mathit e}^{+}} )}$ $/$ $\Gamma\mathrm {(total)}$ $<2.7\times 10^{-6}$ CL=90.0%
 
[1] This limit is for either ${{\mathit D}^{0}}$ or ${{\overline{\mathit D}}^{0}}$ to ${{\overline{\mathit p}}}{{\mathit e}^{+}}$ .
[2] This limit is for either ${{\mathit D}^{0}}$ or ${{\overline{\mathit D}}^{0}}$ to ${{\mathit p}}{{\mathit e}^{-}}$ .
[3] The first limit is for ${{\mathit p}}$ $\rightarrow$ anything or ''disappearance'' modes of a bound proton. The second entry, a rough range of limits, assumes the dominant decay modes are among those investigated. For antiprotons the best limit, inferred from the observation of cosmic ray ${{\overline{\mathit p}}}$'s is ${\mathit \tau}_{{{\overline{\mathit p}}}}$ $>$ $10^{7}$ yr, the cosmic-ray storage time, but this limit depends on a number of assumptions. The best direct observation of stored antiprotons gives ${\mathit \tau}_{{{\overline{\mathit p}}}}$/B( ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit e}^{-}}{{\mathit \gamma}}$ ) $>7 \times 10^{5}$ yr.
[4] There is some controversy about whether nuclear physics and model dependence complicate the analysis for bound neutrons (from which the best limit comes). The first limit here is from reactor experiments with free neutrons.