For each interaction type, strong (S), electromagnetic (EM)...

For each interaction type, strong (S), electromagnetic (EM) and weak (W), insert a $\mathrm{Y}$ or $\mathrm{N}$ in the cell of every quantum number, depending on whether it is conserved or not ( $I$ isospin, $I_z$ its third component, $S$ strangeness, $\mathcal{B}$ baryon number, $\mathcal{L}$ lepton number, $\mathcal{T}$ time reversal, $\mathcal{C}$ particle-antiparticle conjugation, $\mathcal{P}$ parity, $J$ angular momentum, $J_z$ its third component). $$ \begin{array}{|c|c|c|c|c|c|c|c|c|c|c|} \hline \begin{array}{l} \text { S } \\ \text { EM } \\ W \end{array} & I & I_z & S & \mathcal{B} & \mathcal{L} & \mathcal{T} & \mathcal{C} & \mathcal{P} & J & J_z \\ \hline \end{array} $$

For each interaction type, strong (S), electromagnetic (EM) and weak (W), insert a $\mathrm{Y}$ or $\mathrm{N}$ in the cell of every quantum number, depending on whether it is conserved or not ( $I$ isospin, $I_z$ its third component, $S$ strangeness, $\mathcal{B}$ baryon number, $\mathcal{L}$ lepton number, $\mathcal{T}$ time reversal, $\mathcal{C}$ particle-antiparticle conjugation, $\mathcal{P}$ parity, $J$ angular momentum, $J_z$ its third component).
$$
\begin{array}{|c|c|c|c|c|c|c|c|c|c|c|}
\hline \begin{array}{l}
\text { S } \\
\text { EM } \\
W
\end{array} & I & I_z & S & \mathcal{B} & \mathcal{L} & \mathcal{T} & \mathcal{C} & \mathcal{P} & J & J_z \\
\hline
\end{array}
$$

Key Concepts

Discrete Symmetries (Parity, Charge Conjugation, Time Reversal)

Discrete symmetries like parity (P), charge conjugation (C), and time reversal (T) are fundamental symmetry operations in physics. They describe how physical processes behave under spatial inversion, particle-antiparticle exchange, and the reversal of time, respectively. The conservation or violation of these symmetries in different interactions reveals deep insights into the laws governing particle physics.

Angular Momentum Conservation

Angular momentum, including its total value and its projection, is a conserved quantity in particle interactions due to rotational symmetry. This conservation law ensures that the sum of angular momenta before and after a reaction remains constant, influencing allowed particle states and reaction products.

Isospin

Isospin is a quantum number related to the symmetry of particles under the strong interaction. It is analogous to the concept of spin but applies to the up and down quark content of nucleons, playing a major role in understanding hadronic reactions and decays.

Strangeness, Baryon Number, and Lepton Number

These quantum numbers are used to characterize specific particle properties. Strangeness is related to the presence of strange quarks, baryon number distinguishes baryons from other particles, and lepton number is used to track leptons. Their conservation or non-conservation in various interactions provides insights into the underlying physics of particle decays and reactions.

Interaction Types in Particle Physics

The three fundamental interactions—strong, electromagnetic, and weak—govern particle behavior. Each interaction respects or violates different conservation laws, leading to unique characteristics in reaction outcomes. Understanding the differences among these interactions is key to predicting and explaining particle processes.

Conservation Laws in Particle Physics

Conservation laws state that certain quantum numbers remain constant throughout any physical process. These laws, such as conservation of baryon number, lepton number, or angular momentum, determine the allowed transitions and decays in particle interactions.

Quantum Numbers

Quantum numbers are numerical values assigned to particles that describe their intrinsic properties such as charge, spin, and other internal symmetries. They are essential for classifying particles and understanding how these properties behave in various interactions or reactions.

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