Particle Physics: The Standard Model and Beyond

The Standard Model

The Standard Model (SM) is the most successful theory in physics, describing 17 fundamental particles and three of four forces. Matter particles (fermions): 6 quarks (up, down, charm, strange, top, bottom) and 6 leptons (electron, muon, tau, and their neutrinos), organized in 3 generations. Force carriers (bosons): photon (electromagnetic), W±/Z⁰ (weak nuclear), 8 gluons (strong nuclear). Higgs boson: discovered at CERN (2012), mass 125 GeV, gives mass to W/Z bosons and fermions via Higgs mechanism (spontaneous symmetry breaking). Gauge symmetry: SU(3)_C × SU(2)_L × U(1)_Y.

Quantum Chromodynamics

QCD describes the strong force between quarks via gluon exchange. Color charge: quarks carry red, green, or blue; antiquarks carry anti-colors. Gluons carry color-anticolor charge — they self-interact (unlike photons). Confinement: quarks cannot exist in isolation — always bound in hadrons (baryons: qqq; mesons: q̄q). Asymptotic freedom (Gross, Politzer, Wilczek, Nobel 2004): coupling decreases at high energies. Lattice QCD: numerical computations on discretized spacetime. Quark-gluon plasma: deconfined matter at T > 10¹² K, recreated at RHIC and LHC (ALICE experiment).

The Higgs Mechanism

Electroweak symmetry breaking: the Higgs field acquires a vacuum expectation value (VEV) v = 246 GeV. Mexican hat potential: V(φ) = -μ²|φ|² + λ|φ|⁴, spontaneous symmetry breaking when μ² > 0. Goldstone bosons "eaten" by W± and Z⁰, giving them mass. Fermion masses: Yukawa coupling to the Higgs field, y_f · v/√2. Higgs boson properties: spin-0, even parity, decays to b̄b (58%), WW* (21%), gg (9%), ττ (6%), ZZ* (3%). Discovery: combined ATLAS and CMS data, 5σ significance. Open questions: is it the SM Higgs or part of extended sector? Is the vacuum stable?

Beyond the Standard Model

SM explains only 5% of the universe — no dark matter, dark energy, or gravity. Hierarchy problem: why is the Higgs mass (125 GeV) so much lighter than the Planck scale (10¹⁹ GeV)? Supersymmetry (SUSY): every fermion has a boson partner and vice versa — natural solution but no experimental evidence yet. Grand Unified Theories (GUTs): SU(5), SO(10) unify strong and electroweak at ~10¹⁶ GeV. String theory: 1D strings vibrating at different frequencies = different particles, requires extra dimensions. Neutrino masses: oscillation experiments prove non-zero masses — not in original SM.

Experimental Frontiers

Large Hadron Collider (LHC): 27 km ring, 13.6 TeV center-of-mass energy, 40 MHz collision rate. HL-LHC (High-Luminosity): 10× more data by 2041. Future Circular Collider (FCC): 91 km, 100 TeV pp — probing new physics. ILC, CLIC, CEPC: e⁺e⁻ colliders for precision Higgs measurements. DUNE (Deep Underground Neutrino Experiment): CP violation in neutrino sector. Neutrinoless double beta decay: Majorana nature of neutrinos (LEGEND, nEXO). Proton decay searches: Super-Kamiokande, Hyper-Kamiokande. Gravitational wave detectors: LIGO/Virgo/KAGRA → Einstein Telescope, LISA.

Try it live

Everything above runs in your browser — open SPH Fluid and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.