Atomic nucleusThe atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford at the University of Manchester based on the 1909 Geiger–Marsden gold foil experiment. After the discovery of the neutron in 1932, models for a nucleus composed of protons and neutrons were quickly developed by Dmitri Ivanenko and Werner Heisenberg.
MesonIn particle physics, a meson () is a type of hadronicsubatomic particle composed of an equal number of quarks and antiquarks, usually one of each, bound together by the strong interaction. Because mesons are composed of quark subparticles, they have a meaningful physical size, a diameter of roughly one femtometre (10 m), which is about 0.6 times the size of a proton or neutron. All mesons are unstable, with the longest-lived lasting for only a few tenths of a nanosecond.Kaonic hydrogenKaonic hydrogen is an exotic atom consisting of a negatively charged kaon orbiting a proton. Such particles were first identified, through their X-ray spectrum, at the KEK proton synchrotron in Tsukuba, Japan in 1997. More detailed studies have been performed at DAFNE in Frascati, Italy. Kaonic hydrogen has been created in very low energy collisions of kaons with the protons in a gaseous hydrogen target.
LeptonClass of elementary particles Generations of matter Fermion categories Elementary particle generation Type Subtype First Second Third Quarks(colored) down-type down strange bottom up-type up charm top Leptons (color-free) charged electron muon tau neutral electron neutrino muon neutrino tau neutrino LeptonLeptons are involved in several processes such as beta decay.CompositionElementary particleStatisticsFermionicGeneration1st, 2nd, 3rdInteractionsElectromagnetism, gravitation, weakSymbolℓAntiparticleAntilepton (ℓ)Types6 (electron, electron neutrino, muon, muon neutrino, tau, tau neutrino)Electric charge+1 e, 0 e, −1 eColor chargeNoSpin1/2 ħBaryon number0 In particle physics, a lepton is an elementary particle of half-integer spin (spin 1/2) that does not undergo strong interactions.
ElectronThe electron (e, or β in nuclear reactions) is a subatomic particle whose electric charge is negative one elementary charge. It is an elementary particle contained in the matter that makes up the universe. All atoms are composed of electrons, as well as varying numbers protons and neutrons, but the electrons have almost 2,000 times less mass than the other two constituents.
Weak interactionIn nuclear physics and particle physics, the weak interaction, weak force or weak nuclear force, is one of the four known fundamental interactions, with the others being electromagnetism, the strong interaction, and gravitation. It is the mechanism of interaction between subatomic particles that is responsible for the radioactive beta decay of atoms: The weak interaction participates in nuclear fission and nuclear fusion.
Quantum chromodynamicsIn theoretical physics, quantum chromodynamics (QCD) is the study of the strong interaction between quarks mediated by gluons. Quarks are fundamental particles that make up composite hadrons such as the proton, neutron and pion. QCD is a type of quantum field theory called a non-abelian gauge theory, with symmetry group SU(3). The QCD analog of electric charge is a property called color.
PionIn particle physics, a pion (, ) or pi meson, denoted with the Greek letter pi (π), is any of three subatomic particles: π, π, and π. Each pion consists of a quark and an antiquark and is therefore a meson. Pions are the lightest mesons and, more generally, the lightest hadrons.
GravityAttraction of masses and energyThe shapes of two massive galaxies in this image evolved under the effects of gravity.In physics, gravity (from Latin gravitas 'weight'), also known as gravitation or a gravitational interaction, is a fundamental interaction, which may be described as the force that draws material objects towards each other.
MuonA muon ( ; from the Greek letter mu (μ) used to represent it) is an elementary particle similar to the electron, with an electric charge of −1 e and a spin of 1/2ħ, but with a much greater mass. It is classified as a lepton. As with other leptons, the muon is not thought to be composed of any constituent particles.
AtomSmallest unit of a chemical elementAtoms are the basic particles of the chemical elements and the fundamental building blocks of matter. An atom consists of a nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished from each other by the number of protons that are in their atoms. For example, any atom that contains 11 protons is sodium, and any atom that contains 29 protons is copper.
ElectromagnetismIn physics, electromagnetism is an interaction that occurs between particles with electric charge via electromagnetic fields. The electromagnetic force is one of the four fundamental forces of nature. It is the dominant force in the interactions of atoms and molecules. Electromagnetism describes and relates the three distinct but closely intertwined phenomena of electricity, magnetism, and optics.*As an Amazon Associate I earn from qualifying purchases.