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Fig. 2: A 3D representation of a delta electron knocked out by a 180 GeV muon, measured with a GridPix detector at the SPS at CERN. The colour indicates the height Otherwise called a knock-on electron, the term "delta ray" is also used in high energy physics to describe single electrons in particle accelerators that are exhibiting ...
Precision tests of QED have been performed in low-energy atomic physics experiments, high-energy collider experiments, and condensed matter systems. The value of α is obtained in each of these experiments by fitting an experimental measurement to a theoretical expression (including higher-order radiative corrections) that includes α as a parameter.
An example of Hund's case (c) is the lowest 3 Π u state of diiodine (I 2), which approximates more closely to case (c) than to case (a). [ 6 ] The selection rules for S {\displaystyle S} , Ω {\displaystyle \Omega } and parity are valid as for cases (a) and (b), but there are no rules for Λ {\displaystyle \Lambda } and Σ {\displaystyle ...
The weak mixing angle or Weinberg angle [2] is a parameter in the Weinberg–Salam theory of the electroweak interaction, part of the Standard Model of particle physics, and is usually denoted as θ W. It is the angle by which spontaneous symmetry breaking rotates the original W 0 and B 0 vector boson plane, producing as a result the Z 0
Local-density approximations (LDA) are a class of approximations to the exchange–correlation (XC) energy functional in density functional theory (DFT) that depend solely upon the value of the electronic density at each point in space (and not, for example, derivatives of the density or the Kohn–Sham orbitals).
While the results of those electron deflection experiments were disputed for a long time, the investigations of the fine structure of the hydrogen lines by Karl Glitscher (based on the work of Arnold Sommerfeld) had already in 1917 provided a clear confirmation of the Lorentz–Einstein formula, because the relativistic expressions for momentum ...
The delta potential is the potential = (), where δ(x) is the Dirac delta function. It is called a delta potential well if λ is negative, and a delta potential barrier if λ is positive. The delta has been defined to occur at the origin for simplicity; a shift in the delta function's argument does not change any of the following results.
The Breit–Wheeler process is the creation of an electron–positron pair following the collision of two high-energy photons (gamma photons). The nonlinear Breit–Wheeler process or multiphoton Breit–Wheeler is the creation of an electron-positron pair from the decay of a high-energy photon (gamma photon) interacting with a strong electromagnetic field such as a laser.