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In particle physics, the term model building usually refers to a construction of new quantum field theories beyond the Standard Model that have certain features making them attractive theoretically or for possible observations in the near future. A model builder typically chooses new quantum fields and their new interactions, attempting to make their combination realistic, testable and physically interesting. Image File history File links Stop_hand. ...
Wikipedia does not have an article with this exact name. ...
In particle physics, a model builder is a physicist whose primary goal is to construct a very specific theory (called the model) that should be directly compared to the experiments. ...
Particles erupt from the collision point of two relativistic (100GeV) gold ions in the STAR detector of the Relativistic Heavy Ion Collider. ...
Quantum field theory (QFT) is the application of quantum mechanics to fields. ...
The Standard Model of Fundamental Particles and Interactions The Standard Model of particle physics is a theory which describes the strong, weak, and electromagnetic fundamental forces, as well as the fundamental particles that make up all matter. ...
The phrase "model builders" is approximately equivalent to the phrase "phenomenologists." Model builders constitute a different group from the experimentalists and "pure theorists"—which essentially means the researchers of string theory"—even though a subset of model builders use tools (and sometimes even the precise rules) defined by string theory. Interaction in the subatomic world: world lines of pointlike particles in the Standard Model or a world sheet swept up by closed strings in string theory String theory is a model of fundamental physics whose building blocks are one-dimensional extended objects (strings) rather than the zero-dimensional points (particles...
Model building is mostly speculative because current particle accelerators can only probe up to a few hundred GeV, where physics is well described by the Standard Model. There is a result of renormalization group theory stating that at low energies, models flow toward universality classes and different models may flow to the same universality class. There reason why there are so many models beyond the Standard Model - hundreds or even thousands - that exist is because the Standard Model is a universality class. The only way to distinguish between these model based solely upon low energy experiments is to look for irrelevant couplings suppressed by the "cutoff scale". And there is no way most of these models can be right. Only one such model out of the hundreds can be right (possibly along with models which are dual to it or effective theory versions of it) and it may even be one which hasn't been considered at all yet! A 1960s single stage 2MeV linear Van de Graaff accelerator, here opened for maintenance A particle accelerator is a device that uses electric and/or magnetic fields to propel electrically charged particles to high speeds. ...
In theoretical physics, renormalization group (RG) refers to a set of techniques and concepts related to the change of physics with the observation scale. ...
In physics, the term renormalization refers to a variety of theoretical concepts and computational techniques revolving either around the idea of rescaling transformations, or around the process of removing infinities from the calculated quantities (see also regularization). ...
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This is analogous to a similar situation in condensed matter physics. If all known is the equations of hydrodynamics, the equation of state and the transport properties of a fluid, no one would be able to tell whether the fluid is made up of atoms or not. And you certainly wouldn't be able to tell if the particles are molecules made up of atoms or plain old unbound atoms or that an atom is made up of electrons orbiting a nucleus. Similarly, if all you know is the electrical properties of a dielectric/insulator/conductor/superconductor, you wouldn't be able to figure out the microscopic electron wavefunctions. Condensed matter physics is the field of physics that deals with the macroscopic physical properties of matter. ...
Unfortunately, all the attempts to look for irrelevant couplings, such as proton decay with flavor changing neutral currents, or anomalous magnetic moments with anomalous electric dipole moments) have come up with very strict tiny bounds. The only nonzero irrelevant coupling that we have measured is the neutrino oscillations coupling. This makes it possible to tweak most models so that the irrelevant couplings become tiny either by raising the scale at which new physics appears or introducing some ad hoc symmetries forbiding these couplings. The standard model of particle physics states that protons are stable, i. ...
In theoretical physics, flavor changing neutral currents (FCNCs) are dangerous fermionic bilinear expressions. ...
In quantum electrodynamics, anomalous magnetic moment of a particle is a contribution of effects of quantum mechanics, expressed by Feynman diagrams with loops, to the magnetic moment of that particle. ...
Neutrino oscillation is a quantum mechanical phenomenon whereby a neutrino created with a specific lepton flavor (electron, muon, or tau) can later be measured to have a different flavor. ...
Of course, it may be argued that there are patterns among the marginal and relevant couplings so that among all the possible models which give rise to the Standard Model universality class, some of them are much simpler than the others and the simpler models have fewer free parameters than there are Standard Model parameters and thereby allowing us to make postdictions, but it is certainly an article of faith that the "true" UV completion of the Standard Model is simple. In theoretical physics, UV completion of a quantum field theory XY is another quantum field theory (or a more generalized theory) LM that reduces to XY below some energy scale (the cutoff of XY). ...
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