Nuclear Physics

Bridge The cosmological matter-antimatter asymmetry (baryon-to-photon ratio eta ~ 6e-10) demands CP-violating physics beyond the Standard Model: the observed CKM CP violation is ten orders of magnitude too small, linking baryogenesis directly to the open problem of CP violation in leptonic and hadronic sectors.

Fields: Astronomy, Cosmology, Particle Physics, Nuclear Physics

The observed universe contains approximately one baryon per 10^9 photons (eta_B ~ 6e-10, measured by CMB and Big Bang nucleosynthesis). A universe that begins matter-antimatter symmetric cannot arrive...

Bridge Cosmological dark matter candidates are thermal or non-thermal relics of specific early-universe phase transitions — WIMPs from electroweak freeze-out, axions from the QCD phase transition at 150 MeV, and primordial black holes from density fluctuations — connecting galactic-scale astrophysical observations to statistical mechanics of symmetry breaking in the early universe.

Fields: Astronomy, Cosmology, Particle Physics, Statistical Physics, Nuclear Physics

The identity of dark matter is inseparable from the statistical physics of phase transitions in the early universe. Each major dark matter candidate is a relic of a specific transition: WIMPs (Weakly ...

Bridge Neutron star interiors probe cold ultra-dense matter whose equation of state ties nuclear theory and QCD-informed models to observable masses, radii, and tidal deformabilities.

Fields: Nuclear Physics, Astrophysics, Dense Matter, Qcd

Neutron stars support masses up to about two solar masses, constraining pressure versus density relations for matter above nuclear saturation. Microscopic models combine nucleonic matter, hyperons, or...

Bridge All chemical elements heavier than hydrogen and helium were forged in stars — the periodic table is a record of stellar evolution history, quantitatively explained by nuclear physics reactions in successive stellar environments.

Fields: Astrophysics, Chemistry, Nuclear Physics

The Burbidge, Burbidge, Fowler & Hoyle (B²FH, 1957) paper established that stellar nucleosynthesis accounts for the cosmic abundance of all elements: pp-chain and CNO cycle produce helium in main-sequ...

Bridge Stellar nucleosynthesis proceeds through a reaction network of hundreds of isotopes connected by nuclear reactions, and the relative abundances of elements produced can be computed by solving the same maximum-flow and steady-state flux equations used in metabolic network analysis and chemical engineering yield problems

Fields: Astrophysics, Nuclear Physics, Network Science

The abundance evolution of nuclides in a stellar burning zone is governed by a coupled ODE network dY_i/dt = sum_j lambda_{ji} Y_j - Y_i sum_k lambda_{ik}, where Y_i are molar abundances and lambda ar...

Bridge Neutron star mass-radius relationships encode the dense matter equation of state, connecting neutron star astrophysics to nuclear symmetry energy and constraining the pressure-density relationship of matter at 2-8 times nuclear saturation density

Fields: Astrophysics, Nuclear Physics, Physics

The neutron star mass-radius curve M(R) is a one-to-one map from the equation of state P(rho), determined by integrating the Tolman-Oppenheimer-Volkoff (TOV) equations; NICER X-ray timing measurements...

Bridge Neutron star interiors at 2-8× nuclear saturation density are the densest observable matter in the universe — the equation of state P(ρ) bridges nuclear physics (strong force) to astrophysics (compact object structure) through the Tolman-Oppenheimer-Volkoff equation, constrained by LIGO/Virgo tidal deformability measurements.

Fields: Astrophysics, Nuclear Physics, Particle Physics, Gravitational Wave Astronomy, Condensed Matter Physics

NEUTRON STAR INTERIOR PHYSICS: Nuclear saturation density: ρ₀ = 2.3×10¹⁴ g/cm³. Neutron star core: ρ = 2-8ρ₀ — accessible to no terrestrial experiment but observable via neutron star structure. TOLMAN...

Bridge Primordial nucleosynthesis is a nuclear reaction network ODE: Big Bang nucleosynthesis (BBN) computes the abundances of H, D, He-3, He-4, and Li-7 from baryon-to-photon ratio η using the same coupled ODE formalism as stellar nucleosynthesis

Fields: Cosmology, Nuclear Physics, Astrophysics

Big Bang nucleosynthesis (BBN) traces abundances X_i(t) of ~26 nuclides from T~10 MeV (t~10⁻² s) to T~0.01 MeV (t~10³ s) using a coupled ODE system: dX_i/dt = Σ_j (production rates) - Σ_j (destruction...

Bridge Nuclear reactor physics bridges chemistry and engineering: the six-factor formula (k = ╬╖fp╬╡P_NL) governs criticality from fission cross-sections, the thorium cycle offers proliferation-resistant breeding, and Generation IV reactor designs (MSR, GFR) pursue passive safety through thermodynamic and neutronics principles.

Fields: Chemistry, Engineering, Nuclear Physics, Nuclear Engineering, Energy

Nuclear fission: ²³⁵U + n → fission products + 2-3 prompt neutrons + ~200 MeV total energy (~170 MeV kinetic energy of fission fragments + 20 MeV from delayed gamma and beta). The criticality co...

Bridge The biological effectiveness of ionising radiation — from DNA strand break probability to tumour control — is quantitatively predicted by the Bethe-Bloch stopping power formula: the linear energy transfer (LET) framework bridges quantum electrodynamics track structure to radiobiological effectiveness (RBE) and clinical tumour control probability (TCP) in proton and heavy-ion cancer therapy.

Fields: Medical Physics, Radiation Biology, Oncology, Nuclear Physics, Quantum Electrodynamics

The Bethe-Bloch formula (Bethe 1930, Bloch 1933) gives the mean energy loss per unit path length for a charged particle traversing matter: -dE/dx = (4πe⁴z²N_A Z)/(m_e v² A) × [ln(2m_e v²/I) - ln(1-β...

Bridge Radiocarbon dating applies the first-order decay law N(t) = N0 * exp(-lambda * t) with lambda = ln2 / 5,730 yr to determine the age of organic material, with Bayesian calibration correcting for past atmospheric C-14 variations using dendrochonology

Fields: Archaeology, Nuclear Physics, Mathematics

Carbon-14 produced by cosmic ray spallation of N-14 enters living organisms at atmospheric concentration N0; after death, N(t) = N0 * exp(-t * ln2 / 5730) with half-life T_1/2 = 5,730 yr (±40 yr); mea...