Astroparticle Physics

318 16 GlossaryNuclei of fixed charge representing the same chemical element al-beit with different masses. The chemical element is characterizedby the atomic number. Therefore, isotopes are nuclei of fixed protonnumber, but variable neutron number.ionizationisomersisospinisotopeJJeans massjetsKK; a meson consisting of a strange quark and an anti-up or anti-down quark or, correspondingly, an anti-strange quark and an upor down quark.KamiokandekaonkpcLlarge attractorlatitude effectLiberation of atomic electrons by photons or charged particles,namely photo ionization and ionization by collision.Long-lived excited states of a nucleus.Hadrons of equal mass (apart from electromagnetic effects) aregrouped into isospin multipletts, in analogy to the spin. Individualmembers of the multipletts are considered to be presented by thethird component of the isospin. Nucleons form an isospin doublet(I = 1 2 , I 3(p) =+ 1 2 , I 3(n) =− 1 2 ) and pions an isospin triplet(I = 1, I 3 (π + ) =+1, I 3 (π − ) =−1, I 3 (π 0 ) = 0).An inhomogeneity in a matter distribution will grow due to gravitationalattraction and contribute to the formation of structure inthe universe (e.g., galaxy formation), if it exceeds a certain criticalsize (Jeans mass).Long narrow streams of matter emerging from radiogalaxies andquasars, or bundles of particles in particle–antiparticle annihilations.Nucleon Decay Experiment in the Japanese Kamioka mine for themeasurement of cosmic and terrestrial neutrinos.Kilo parsec (see parsec).Hypothetical supercluster complex with a mass of > 10 4 galaxiesat a distance of several 100 million light-years which impresses anoriented proper motion on the local group of galaxies.Increase of the cosmic-ray intensity to the geomagnetic polescaused by the interaction of charged primary cosmic rays withthe Earth’s magnetic field.