In particle physics, proton decay is a hypothetical form of particle decay in which the proton decays into lighter subatomic particles, such as a neutral pion and a positron. The proton decay hypothesis was first formulated by Andrei Sakharov in 1967. Despite significant experimental effort, proton decay has never been observed. If it does decay via a positron, the proton's half-life is constrained to be at least 1.67×1034 years.
Weakly interacting massive particles (WIMPs) are hypothetical particles that are one of the proposed candidates for dark matter.
In a supersymmetric theory the equations for force and the equations for matter are identical. In theoretical and mathematical physics, any theory with this property has the principle of supersymmetry (SUSY). Dozens of supersymmetric theories exist. Supersymmetry is a spacetime symmetry between two basic classes of particles: bosons, which have an integer-valued spin and follow Bose–Einstein statistics, and fermions, which have a half-integer-valued spin and follow Fermi–Dirac statistics. In supersymmetry, each particle from one class would have an associated particle in the other, known as its superpartner, the spin of which differs by a half-integer. For example, if the electron exists in a supersymmetric theory, then there would be a particle called a selectron, a bosonic partner of the electron. In the simplest supersymmetry theories, with perfectly "unbroken" supersymmetry, each pair of superpartners would share the same mass and internal quantum numbers besides spin. More complex supersymmetry theories have a spontaneously broken symmetry, allowing superpartners to differ in mass.
R-parity is a concept in particle physics. In the Minimal Supersymmetric Standard Model, baryon number and lepton number are no longer conserved by all of the renormalizable couplings in the theory. Since baryon number and lepton number conservation have been tested very precisely, these couplings need to be very small in order not to be in conflict with experimental data. R-parity is a symmetry acting on the Minimal Supersymmetric Standard Model (MSSM) fields that forbids these couplings and can be defined as
In theoretical physics, an extremal black hole is a black hole with the minimum possible mass that is compatible with its charge and angular momentum.
In theoretical physics, the hierarchy problem is the problem concerning the large discrepancy between aspects of the weak force and gravity. There is no scientific consensus on why, for example, the weak force is 1024 times stronger than gravity.
Montonen–Olive duality or electric–magnetic duality is the oldest known example of strong–weak duality or S-duality according to current terminology. It generalizes the electro-magnetic symmetry of Maxwell's equations by stating that magnetic monopoles, which are usually viewed as emergent quasiparticles that are "composite", can in fact be viewed as "elementary" quantized particles with electrons playing the reverse role of "composite" topological solitons; the viewpoints are equivalent and the situation dependent on the duality. It was later proven to hold true when dealing with a N = 4 supersymmetric Yang–Mills theory. It is named after Finnish physicist Claus Montonen and British physicist David Olive after they proposed the idea in their academic paper Magnetic monopoles as gauge particles? where they state:
There should be two "dual equivalent" field formulations of the same theory in which electric (Noether) and magnetic (topological) quantum numbers exchange roles.
Burt Ovrut is an American theoretical physicist best known for his work on heterotic string theory. He is currently Professor of Theoretical High Energy Physics at the University of Pennsylvania.
Physics beyond the Standard Model (BSM) refers to the theoretical developments needed to explain the deficiencies of the Standard Model, such as the inability to explain the fundamental parameters of the standard model, the strong CP problem, neutrino oscillations, matter–antimatter asymmetry, and the nature of dark matter and dark energy. Another problem lies within the mathematical framework of the Standard Model itself: the Standard Model is inconsistent with that of general relativity, and one or both theories break down under certain conditions, such as spacetime singularities like the Big Bang and black hole event horizons.
The axino is a hypothetical elementary particle predicted by some theories of particle physics. Peccei–Quinn theory attempts to explain the observed phenomenon known as the strong CP problem by introducing a hypothetical real scalar particle called the axion. Adding supersymmetry to the model predicts the existence of a fermionic superpartner for the axion, the axino, and a bosonic superpartner, the saxion. They are all bundled up in a chiral superfield.
Mark Trodden is a theoretical cosmologist and particle physicist. He is the Fay R. and Eugene L. Langberg Professor of Physics and Co-Director of the Center for Particle Cosmology at the University of Pennsylvania.
In particle physics and string theory (M-theory), the ADD model, also known as the model with large extra dimensions (LED), is a model framework that attempts to solve the hierarchy problem. The model tries to explain this problem by postulating that our universe, with its four dimensions, exists on a membrane in a higher dimensional space. It is then suggested that the other forces of nature operate within this membrane and its four dimensions, while the hypothetical gravity-bearing particle graviton can propagate across the extra dimensions. This would explain why gravity is very weak compared to the other fundamental forces. The size of the dimensions in ADD is around the order of the TeV scale, which results in it being experimentally probeable by current colliders, unlike many exotic extra dimensional hypotheses that have the relevant size around the Planck scale.
In particle physics, W′ and Z′ bosons refer to hypothetical gauge bosons that arise from extensions of the electroweak symmetry of the Standard Model. They are named in analogy with the Standard Model W and Z bosons.
In astrophysics and cosmology scalar field dark matter is a classical, minimally coupled, scalar field postulated to account for the inferred dark matter.
In supergravity and supersymmetric representation theory, Adinkra symbols are a graphical representation of supersymmetric algebras. Mathematically they can be described as colored finite connected simple graphs, that are bipartite and n-regular. Their name is derived from Adinkra symbols of the same name, and they were introduced by Michael Faux and Sylvester James Gates in 2004.
The FRW/CFT duality is a conjectured duality for Friedmann–Robertson–Walker models inspired by the AdS/CFT correspondence. It assumes that the cosmological constant is exactly zero, which is only the case for models with exact unbroken supersymmetry. Because the energy density does not approach zero as we approach spatial infinity, the metric is not asymptotically flat. This is not an asymptotically cold solution.
Goran Senjanović is a theoretical physicist at the Abdus Salam International Centre for Theoretical Physics (ICTP). He received his Ph.D. at the City College of New York in 1978, under the supervision of Rabindra Mohapatra. Before joining the ICTP in 1991, he worked as a staff member at the Brookhaven National Laboratory and as a professor of physics at the University of Zagreb. His major research interests are neutrino physics, unification of elementary particle forces, baryon and lepton number violation and supersymmetry.
Atish Dabholkar is an Indian theoretical physicist. He is currently the Director of the Abdus Salam International Centre for Theoretical Physics (ICTP) with the rank of Assistant Director-General, UNESCO. Prior to that, he was head of ICTP's High Energy, Cosmology and Astroparticle Physics section, and also Directeur de Recherche at the Centre National de la Recherche Scientifique (CNRS) at Sorbonne University in the "Laboratoire de Physique Théorique et Hautes Énergies" (LPTHE).
Zvi Bern is an American theoretical particle physicist. He is a professor at University of California, Los Angeles (UCLA).
Céline Bœhm is a Professor of Particle Physics at the University of Sydney. She works on astroparticle physics and dark matter.
