We list first the reaction and then the quark composition. Keep in mind that these decays all occur by the weak interaction in which quark transformations can occur. We have not discussed this, but it is because these decays occur by exchange of the W ^{\pm} gauge bosons.
\Xi^{-} \rightarrow \Lambda^{0}+\pi^{-} \quad d s s \rightarrow u d s+\bar{u} d
A s quark is changed to a d quark, and an \bar{u} u pair is created.
\Lambda^{0} \rightarrow p+\pi^{-} \quad u d s \rightarrow u u d+\bar{u} d
Again a s quark is changed to a d quark, and an \bar{u} u pair is created.
\pi^{-} \rightarrow \mu^{+}+\nu_{\mu} \quad \bar{u} d \rightarrow \text { no quarks }
The d quark can change to an u quark and annihilate the existing \bar{u} quark.
| Table 14.4 The Hadrons |
|
Baryon |
Strangeness |
Charm |
| Particle |
|
Anti- |
Mass |
Mean |
Main Decay |
Number |
Number |
Number |
| Name |
Symbol |
particle |
\left( MeV / c^{2}\right) |
Lifetime (s) |
Modes |
Spin |
B |
S |
C |
| Mesons |
|
| Pion |
\pi^{-} |
\pi^{+} |
140 |
2.6 \times 10^{-8} |
\mu^{+} \nu_{\mu} |
0 |
0 |
0 |
0 |
|
\pi^{+} |
Self |
135 |
8.4 \times 10^{-17} |
2 \gamma |
0 |
0 |
0 |
0 |
| Kaon |
K ^{+} |
K ^{-} |
494 |
1.2 \times 10^{-8} |
\mu^{+} \nu_{\mu}, \pi^{+} \pi^{0} |
0 |
0 |
1 |
0 |
|
K _{S}^{0} |
\overline{K _{S}^{0}} |
498 |
8.9 \times 10^{-11} |
\pi^{+} \pi^{-}, 2 \pi^{0} |
0 |
0 |
1 |
0 |
|
K _{L}^{0} |
\overline{K _{L}^{0}} |
498 |
5.1\times 10^{-8} |
\pi^{\pm} e^{\mp} \nu_{e}, 3 \pi^{0}, |
0 |
0 |
1 |
0 |
|
\pi^{\pm} \mu^{\mp} \nu_{\mu}, |
|
| \pi^{+} \pi^{-} \pi^{0} |
| Eta |
\eta^{0} |
Self |
548 |
5\times 10^{-19} |
2 \gamma, 3 \pi^{0}, |
0 |
0 |
0 |
0 |
|
\pi^{+} \pi^{-} \pi^{0} |
|
| Charmed |
D ^{+} |
D ^{-} |
1870 |
1.0 \times 10^{-12} |
e^{+}, K^{\pm}, K^{0}, |
0 |
0 |
0 |
1 |
| D’s |
|
|
|
|
\overline{{K}^{0}}+\text { anything } |
|
D ^{0} |
\overline{ D^{0} } |
1865 |
4.1 \times 10^{-13} |
\text { Same as } D ^{+} |
0 |
0 |
0 |
1 |
|
D _{S}^{+} |
\overline{ D^{-}_{S} } |
1968 |
5.0 \times 10^{-13} |
Various |
0 |
0 |
1 |
1 |
| Bottom B’s |
B^{+} |
B^{-} |
5279 |
1.6 \times 10^{-12} |
Various |
0 |
0 |
0 |
0 |
|
B^{0} |
\overline{ B }^{0} |
5279 |
1.5 \times 10^{-12} |
Various |
0 |
0 |
0 |
0 |
| J/Psi |
J / \psi |
Self |
3097 |
7.1 \times 10^{-21} |
Various |
0 |
0 |
0 |
0 |
| Upsilon |
\Upsilon (1 S) |
Self |
9460 |
1.2 \times 10^{-20} |
Various |
0 |
0 |
0 |
0 |
| Baryons |
|
| Proton |
p |
\bar{p} |
938.3 |
Stable (?) |
|
\frac{1}{2} |
1 |
0 |
0 |
| Neutron |
n |
\bar{n} |
939.6 |
886 |
p e^{-}\bar{\nu}_{e} |
\frac{1}{2} |
1 |
0 |
0 |
| Lambda |
\Lambda |
\bar{\Lambda} |
1116 |
2.6 \times 10^{-10} |
p \pi^{-}, n \pi^{0} |
\frac{1}{2} |
1 |
-1 |
0 |
| Sigmas |
\Sigma^{+} |
\bar{\Sigma}^{-} |
1189 |
8.0 \times 10^{-11} |
p \pi^{0}, n \pi^{+} |
\frac{1}{2} |
1 |
-1 |
0 |
|
\Sigma^{0} |
\bar{\Sigma}^{0} |
1193 |
7.4 \times 10^{-20} |
\Lambda \gamma |
\frac{1}{2} |
1 |
-1 |
0 |
|
\Sigma^{-} |
\bar{\Sigma}^{+} |
1197 |
1.5 \times 10^{-10} |
n \pi^{-} |
\frac{1}{2} |
1 |
-1 |
0 |
| Xi |
\Xi^{0} |
\bar{\Xi}^{0} |
1315 |
2.9 \times 10^{-10} |
\Lambda \pi^{0} |
\frac{1}{2} |
1 |
-2 |
0 |
|
\Xi^{-} |
\Xi^{+} |
1322 |
1.6 \times 10^{-10} |
\Lambda \pi^{-} |
\frac{1}{2} |
1 |
-2 |
0 |
| Omega |
\Omega^{-} |
\Omega^{+} |
1672 |
0.82 \times 10^{-10} |
\Lambda K ^{-}, {\Xi}^{0} \pi^{-} |
\frac{1}{2} |
1 |
-3 |
0 |
| Charmed |
\Lambda_{C}^{+} |
\bar{\Lambda}_{C}^{-} |
2286 |
2.0 \times 10^{-13} |
Various |
\frac{1}{2} |
1 |
0 |
1 |
| lambda |
|
| Review of Particle Physics, K. Nakamura et al. (Particle Data Group), Journal of Physics G37, 075021 (2010) |
| Table 14.6 Quark Composition of Selected Hadrons |
|
Quark |
| Particle |
Composition |
| Mesons |
|
| \pi^{+} |
u \bar{d} |
| \pi^{-} |
\bar{u} d |
| K^{+} |
u \bar{s} |
| K^{0} |
d \bar{s} |
| D^{+} |
c \bar{d} |
| D^{0} |
c \bar{u} |
| Baryons |
|
| Particle |
uud |
| n |
udd |
| \Lambda |
uds |
| \Sigma^{+} |
uus |
| \Sigma^{0} |
uds |
| \Xi^{0} |
uss |
| \Xi^{-} |
dss |
| \Omega^{-} |
sss |
| \Lambda_{C}^{+} |
udc |
