A neutrino is a fermion that interacts only via the weak subatomic force and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is so small (-ino) that it was long thought to be zero. The mass of the neutrino is much smaller than that of the other known elementary particles. The weak force has a very short range, the gravitational interaction is extremely weak, and neutrinos, as leptons, do not participate in the strong interaction. Thus, neutrinos typically pass through normal matter unimpeded and undetected.
The Greisen–Zatsepin–Kuzmin limit (GZK limit) is a theoretical upper limit on the energy of cosmic ray protons traveling from other galaxies through the intergalactic medium to our galaxy. The limit is 5×1019 eV, or about 8 joules. The limit is set by slowing interactions of the protons with the microwave background radiation over long distances (~160 million light-years). The limit is at the same order of magnitude as the upper limit for energy at which cosmic rays have experimentally been detected. For example, one extreme-energy cosmic ray has been detected which appeared to possess a record 3.12×1020 eV (50 joules) of energy (about the same as the kinetic energy of a 95 km/h baseball).
In physics, a chiral anomaly is the anomalous nonconservation of a chiral current. In everyday terms, it is equivalent to a sealed box that contained equal number of positive and negative charged particles, that when opened was found to have more positive than negative particles, or vice versa.
A sphaleron is a static (time-independent) solution to the electroweak field equations of the Standard Model of particle physics, and is involved in certain hypothetical processes that violate baryon and lepton numbers. Such processes cannot be represented by perturbative methods such as Feynman diagrams, and are therefore called non-perturbative. Geometrically, a sphaleron is a saddle point of the electroweak potential.
In physical cosmology, leptogenesis is the generic term for hypothetical physical processes that produced an asymmetry between leptons and antileptons in the very early universe, resulting in the present-day dominance of leptons over antileptons. In the currently accepted Standard Model, lepton number is conserved; it is not possible to create leptons directly without corresponding antileptons. Leptogenesis can therefore only take place in theories of physics beyond the Standard Model.
In physics, the baryon asymmetry problem, also known as the matter asymmetry problem or the matter-antimatter asymmetry problem, is the observed imbalance in baryonic matter and antibaryonic matter in the observable universe. Neither the standard model of particle physics, nor the theory of general relativity provides a known explanation for why this should be so, and it is a natural assumption that the universe be neutral with all conserved charges. The Big Bang should have produced equal amounts of matter and antimatter. Since this does not seem to have been the case, it is likely some physical laws must have acted differently or did not exist for matter and antimatter. Several competing hypotheses exist to explain the imbalance of matter and antimatter that resulted in baryogenesis. However, there is as of yet no consensus theory to explain the phenomenon. As remarked in a 2012 research paper, "The origin of matter remains one of the great mysteries in physics."
Astroparticle physics, also called particle astrophysics, is a branch of particle physics that studies elementary particles of astronomical origin and their relation to astrophysics and cosmology. It is a relatively new field of research emerging at the intersection of particle physics, astronomy, astrophysics, detector physics, relativity, solid state physics, and cosmology. Partly motivated by the discovery of neutrino oscillation, the field has undergone rapid development, both theoretically and experimentally, since the early 2000s.
Artem Isahaki (Isaakovich) Alikhanian was a Soviet Armenian physicist, one of the founders and first director of the Yerevan Physics Institute, a correspondent member of the Academy of Sciences of the USSR (1946), academic of the Armenian Academy of Sciences. With Pyotr Kapitsa, Lev Landau, Igor Kurchatov, Abraham Alikhanov and others, he laid the foundations of nuclear physics in the Soviet Union. He is known as the "father of Armenian physics".
The Pomeranchuk Prize is an international award for theoretical physics, awarded annually since 1998 by the Institute for Theoretical and Experimental Physics (ITEP) from Moscow. It is named after Russian physicist Isaak Yakovlevich Pomeranchuk, who together with Landau established the Theoretical Physics Department of the Institute.
Aleksandr Evgenievich Chudakov was a Soviet Russian physicist in the field of cosmic-ray physics, known for Chudakov Effect, the effect of decreasing ionization losses for narrow electron-positron pairs and for experimentally confirming existence of the transition radiation. He was also the chairman of the IUPAP Cosmic Ray Commission.
Moisey Alexandrovich Markov was a Soviet physicist-theorist who mostly worked in the area of quantum mechanics, nuclear physics and particle physics He is particularly known for having proposed the idea of underwater neutrino telescopes in 1960 that was originally developed in the master thesis of his student Igor Mikhailovich Zheleznykh.
The Affleck–Dine mechanism is a postulated mechanism for explaining baryogenesis during the primordial Universe immediately following the Big Bang. Thus, the AD mechanism may explain the asymmetry between matter and anti-matter in the current Universe. It was proposed in 1985 by Ian Affleck and Michael Dine of Princeton University.
The neutrino minimal standard model is an extension of the Standard Model of particle physics, by the addition of three right-handed neutrinos with masses smaller than the electroweak scale. Introduced by Takehiko Asaka and Mikhail Shaposhnikov in 2005., it has provided a highly constrained model for many topics in physics and cosmology, such as baryogenesis and neutrino oscillations.
Vladimir Mikhailovich Lobashev was a Russian physicist and expert in nuclear physics and particle physics. He authored over 200 papers, of which 25 were considered groundbreaking.
Valery Anatolyevich Rubakov is a Russian theoretical physicist. His scientific interests include quantum field theory, elementary particle physics, and cosmology. He is affiliated with the Institute for Nuclear Research (INR) of the Russian Academy of Sciences in Moscow.
