In physics, quasielastic scattering designates a limiting case of inelastic scattering, characterized by energy transfers being small compared to the incident energy of the scattered particles.
The term was originally coined in nuclear physics. [1]
It was applied to thermal neutron scattering by Leon van Hove [2] and Pierre Gilles de Gennes [3] (quasielastic neutron scattering, QENS).
Finally, it is sometimes used for dynamic light scattering (also known by the more expressive term photon correlation spectroscopy).
The interacting boson model (IBM) is a model in nuclear physics in which nucleons (protons or neutrons) pair up, essentially acting as a single particle with boson properties, with integral spin of either 2 (d-boson) or 0 (s-boson). They correspond to a quintuplet and singlet, i.e. 6 states.
String field theory (SFT) is a formalism in string theory in which the dynamics of relativistic strings is reformulated in the language of quantum field theory. This is accomplished at the level of perturbation theory by finding a collection of vertices for joining and splitting strings, as well as string propagators, that give a Feynman diagram-like expansion for string scattering amplitudes. In most string field theories, this expansion is encoded by a classical action found by second-quantizing the free string and adding interaction terms. As is usually the case in second quantization, a classical field configuration of the second-quantized theory is given by a wave function in the original theory. In the case of string field theory, this implies that a classical configuration, usually called the string field, is given by an element of the free string Fock space.
X-ray absorption fine structure (XAFS) is a specific structure observed in X-ray absorption spectroscopy (XAS). By analyzing the XAFS, information can be acquired on the local structure and on the unoccupied local electronic states.
A three-body force is a force that does not exist in a system of two objects but appears in a three-body system. In general, if the behaviour of a system of more than two objects cannot be described by the two-body interactions between all possible pairs, as a first approximation, the deviation is mainly due to a three-body force.
The λ (lambda) universality class is a group in condensed matter physics. It regroups several systems possessing strong analogies, namely, superfluids, superconductors and smectics. All these systems are expected to belong to the same universality class for the thermodynamic critical properties of the phase transition. While these systems are quite different at the first glance, they all are described by similar formalisms and their typical phase diagrams are identical.
Berkelium (97Bk) is an artificial element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 243Bk in 1949. There are 19 known radioisotopes, from 233Bk to 253Bk, and 6 nuclear isomers. The longest-lived isotope is 247Bk with a half-life of 1,380 years.
Léon Charles Prudent Van Hove was a Belgian physicist and a Director General of CERN. He developed a scientific career spanning mathematics, solid state physics, elementary particle and nuclear physics to cosmology.
Delbrück scattering, the deflection of high-energy photons in the Coulomb field of nuclei as a consequence of vacuum polarization, was observed in 1975. The related process of the scattering of light by light, also a consequence of vacuum polarization, was not observed until 1998. In both cases, it is a process described by quantum electrodynamics.
John (Jean) Iliopoulos is a Greek physicist. He is the first person to present the Standard Model of particle physics in a single report. He is best known for his prediction of the charm quark with Sheldon Glashow and Luciano Maiani. Iliopoulos is also known for demonstrating the cancellation of anomalies in the Standard model. He is further known for the Fayet-Iliopoulos D-term formula, which was introduced in 1974. He is currently an honorary member of Laboratory of theoretical physics of École Normale Supérieure, Paris.
S-matrix theory was a proposal for replacing local quantum field theory as the basic principle of elementary particle physics.
Francisco José Ynduráin Muñoz was a Spanish theoretical physicist. He founded the particle physics research group that became the Department of Theoretical Physics at the Autonomous University of Madrid, where he was a Professor. He was described by his colleagues as "a scientist that always searched for excellence in research".
In physics, vector meson dominance (VMD) was a model developed by J. J. Sakurai in the 1960s before the introduction of quantum chromodynamics to describe interactions between energetic photons and hadronic matter.
Hot spots in subatomic physics are regions of high energy density or temperature in hadronic or nuclear matter.
Quasielastic neutron scattering (QENS) designates a limiting case of inelastic neutron scattering, characterized by energy transfers being small compared to the incident energy of the scattered particles. In a more strict meaning, it denotes scattering processes where dynamics in the sample lead to a broadening of the incident neutron spectrum, in contrast to, e.g., the scattering from a diffusionless crystal, where the scattered neutron energy spectrum consists of an elastic line and a number of well-separated inelastic lines due to the creation or annihilation of phonons with specific energies.
Erwin Gabathuler was a particle physicist from Northern Ireland.
Tom Wilkerson Bonner was an American experimental physicist who developed important instruments and techniques for neutron physics and nuclear physics.
Stephan Narison is a Malagasy theoretical high-energy physicist specialized in quantum chromodynamics (QCD), the gauge theory of strong interactions. He is the founder of the Series of International Conferences in Quantum Chromodynamics (QCD-Montpellier) and of the Series of International Conferences in High-Energy Physics (HEPMAD-Madagascar).
Magda Galula Ericson (born 1929) is a French-Algerian physicist of Tunisian origin. Her experimental pioneering PhD work changed the understanding of critical phenomena near the Curie point and later in her career she has become known for her theoretical development of the Ericson-Ericson Lorentz-Lorenz correction.
Frances Pleasonton (1912–1990) was a Particle Physicist at the Oak Ridge National Laboratory. She was an active teacher and researcher, and a member of the team who first demonstrated neutron decay in 1951.
James Philip "Phil" Elliott was a British theoretical nuclear physicist.