Interface of high-energy particle physics with cosmology and astrophysics: ultra-high-energy cosmic rays, extensive air showers, astrophysical neutrinos (IceCube), gamma-ray astronomy (HESS, CTA, Fermi-LAT), dark-matter direct detection…
astroparticle-physics
Cosmic-ray primary spectrum: dN/dE ∝ E^{−2.7} below knee, E^{−3.0} above
All-particle cosmic-ray differential flux follows a broken power-law. Below the 'knee' (~3·10¹⁵ eV = 3 PeV), dN/dE ∝ E^{−2.7}: galactic…
GZK cutoff: E_th = (m_Δ² − m_p²)/(4·E_CMB) ≈ 5·10¹⁹ eV via p + γ_CMB → Δ⁺ → pπ⁰
Greisen-Zatsepin-Kuzmin (1966) cutoff: ultra-high-energy protons travelling through the CMB photon bath (T = 2.725 K, typical ω ≈ 6·10⁻⁴…
Heitler EAS toy: N_max = E₀/E_c, X_max = X₀·log₂(E₀/E_c) for EM cascade
Heitler's toy model (1954) for electromagnetic extensive air showers: after each splitting length X₀ = ln(2)·X_r (one radiation length…
Neutrino astronomy (IceCube): diffuse astrophysical νₑ,ν_μ,ν_τ at TeV-PeV
IceCube (2013+) detects astrophysical neutrinos at TeV-PeV energies via Cherenkov light from secondary muons (tracks) and…
Dark-matter direct detection: WIMP nuclear recoil, rate R ∝ ρ_χ·σ·⟨v⟩/m_χ
WIMPs from the galactic halo (local density ρ_χ ≈ 0.3-0.4 GeV/cm³, v̄ ≈ 220 km/s Maxwell-Boltzmann) scatter elastically off target nuclei…
Axion haloscope: resonant cavity → microwave photon via B·a coupling
Sikivie-style axion haloscope (1983): halo dark-matter axions a with mass m_a ~ μeV convert into microwave photons of the same frequency ν…