Nuclear and Quantum Physics - The Structure of Matter

The Standard Model categorizes all fundamental particles into two groups: fermions (matter particles) and bosons (force carriers).

Fermions are further divided into quarks and leptons. There are six flavors of quarks: up ($u$), down ($d$), charm ($c$), strange ($s$), top ($t$), and bottom ($b$).

Quarks carry fractional electric charges: $u, c, t$ have charge $+\frac{2}{3}e$, while $d, s, b$ have charge $-\frac{1}{3}e$. All quarks have a baryon number of $B = +\frac{1}{3}$.

Leptons are fundamental particles that do not experience the strong nuclear force. They include the electron ($e^-$), muon ($\mu^-$), tau ($\tau^-$), and their corresponding neutrinos ($\nu_e, \nu_\mu, \nu_\tau$).

Hadrons are particles made of quarks. They are divided into Baryons (made of three quarks, e.g., proton $uud$ and neutron $udd$) and Mesons (made of a quark-antiquark pair, e.g., pion $\pi^+ = u\bar{d}$).

Fundamental forces are mediated by exchange particles (gauge bosons): Photons ($\gamma$) for Electromagnetism, Gluons ($g$) for the Strong force, $W^+$, $W^-$, and $Z^0$ for the Weak force, and Gravitons for Gravity.

Conservation Laws: In all particle interactions, Charge ($Q$), Baryon number ($B$), and Lepton numbers ($L_e, L_\mu, L_\tau$) must be conserved. Strangeness ($S$) is conserved in strong and electromagnetic interactions but can be violated in weak interactions.

Confinement: Quarks cannot exist in isolation due to the increasing potential energy between them as they are pulled apart; the energy becomes sufficient to create a new quark-antiquark pair.