What is Standard model: Definition and 273 Discussions

The Standard Model of particle physics is the theory describing three of the four known fundamental forces (the electromagnetic, weak, and strong interactions, and not including gravity) in the universe, as well as classifying all known elementary particles. It was developed in stages throughout the latter half of the 20th century, through the work of many scientists around the world, with the current formulation being finalized in the mid-1970s upon experimental confirmation of the existence of quarks. Since then, confirmation of the top quark (1995), the tau neutrino (2000), and the Higgs boson (2012) have added further credence to the Standard Model. In addition, the Standard Model has predicted various properties of weak neutral currents and the W and Z bosons with great accuracy.
Although the Standard Model is believed to be theoretically self-consistent and has demonstrated huge successes in providing experimental predictions, it leaves some phenomena unexplained and falls short of being a complete theory of fundamental interactions. It does not fully explain baryon asymmetry, incorporate the full theory of gravitation as described by general relativity, or account for the accelerating expansion of the Universe as possibly described by dark energy. The model does not contain any viable dark matter particle that possesses all of the required properties deduced from observational cosmology. It also does not incorporate neutrino oscillations and their non-zero masses.
The development of the Standard Model was driven by theoretical and experimental particle physicists alike. For theorists, the Standard Model is a paradigm of a quantum field theory, which exhibits a wide range of phenomena including spontaneous symmetry breaking, anomalies and non-perturbative behavior. It is used as a basis for building more exotic models that incorporate hypothetical particles, extra dimensions, and elaborate symmetries (such as supersymmetry) in an attempt to explain experimental results at variance with the Standard Model, such as the existence of dark matter and neutrino oscillations.

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  1. J

    Lorentz Violation of the Standard Model

    Recently I have posted a preprint on the web (http://xxx.lanl.gov/abs/hep-ph/0502142) that contradicts the conclusion of the unification of electroweak interactions, which is the very reason the Standard Model is awarded Nobel prize. Before putting this preprint, I have asked as many...
  2. CarlB

    A Geometric Approach to the Standard Model, Greg Trayling

    A Geometric Approach to the Standard Model Greg Trayling, Dept of Phys, U. Windsor, Windsor, Ontario A geometric approach to the standard model of the Clifford algebra \mathcal{CL}_7 is advanced. The gauge symmetries and charge assignments of the fundamental fermions are seen to arise from a...
  3. marcus

    How Standard Model numbers arise from LQG

    One way to achieve a degree of unification in physics would be to show how key aspects of the Standard Model of particle theory emerge from Loop Quantum Gravity. At the October QG conference Lee Smolin offered some ideas as to how that might happen. It involved having the links of the spin...
  4. marcus

    Baez links Standard Model symmetries to Calabi-Yaus

    new preprint http://arxiv.org/abs/hep-th/0511086 Calabi-Yau Manifolds and the Standard Model John C. Baez 4 pages "For any subgroup G of O(n), define a "G-manifold" to be an n-dimensional Riemannian manifold whose holonomy group is contained in G. Then a G-manifold where G is the Standard Model...
  5. K

    Standard Model particle spectrum from String Theory

    Interesting post here http://motls.blogspot.com/2005/10/heterotic-mssm.html#comments It seems that a group of researchers has constructed a Calabi-Yau compactification that reproduces that particles of the standard model. The also obtain the SO(10) GUT group, and seem to get rid of some of...
  6. D

    Force carriers / standard model

    I've heard electromagnetic wave propagation described as a 'swarm of photons'. This makes sense to me in terms of the standard model, wrt. the photon being the 'carrier particle' for electromagnetism. However, what about something with a static electric field - what's the 'carrier particle' for...
  7. D

    Symmetry, groups and gauge theories in the standard model

    This is my (limited) understanding of particle physics: In particle physics gauge symmetries play an important role. To allow for massive gauge bosons this symmetry is broken. The theory of weak interactions can be derived from a local SU(2) symmetry, and quantumchromodynamics from a local SU(3)...
  8. T

    Complete Standard Model & Quantum Mechanics Guide

    Hey guys, Just wondering if there is a single book / website / paper with the entire standard model in it to date. e.g one giant book with everything about classical physics (facts and equations) in it... what about one about the entire of Quantum Mechanics to date? I only ask because...
  9. N

    The Standard Model: Leptons, Quarks & Bosons

    Would it be safe to say that according to the standard model of particle physics all that actually exists at the most fundamental level are leptons, quarks, and bosons?
  10. K

    Gravity and the standard model

    gravity and the standard model and Higgs theory Massless particles always exist in a gravitational field, in the real universe.The standard model does not reflect this,so how can the standard model of particle physics be correct.And how can the Higgs theory of mass generation which is linked to...
  11. K

    Yang-mills and standard model

    What in simple terms is a Yang-Mills field? What has it got to do with the standard model of particle physics and why are all particles in the standard model massless - is this something to do with getting the standard model to be consistent with the Higgs field? Do we need the standard...
  12. arivero

    Beyond minimal standard model.

    Has anyone got good pointed in higgs models beyond the minimal? The PDG review is too small for my taste. From Lamb's balance, I am getting the prediction of the following particle spectra 68 GeV. According L3, it could be H+ Z0 as usual, and W+ as usual, almost 115 GeV. According ALEPH...
  13. J

    New theta pentaquark and standard model

    Polemically speaking, if the standard model is so good, and we understand it so well, how come there are so many different explanations for the new theta pentaquark? What is that guy, anyway? All the best, Jim Graber
  14. N

    Standard Model Particle Variation

    The Standard Model of particle physics provides no explanation for the masses of the basic particles. If the masses were much larger- a possibility for a variation of the model- then a small collection of particles could collapse in a black hole. Of course this universe would be different from...
  15. T

    Terry Giblin Standard Model

    DIMENSION THROW PROB. SPIN CHARGE NAME COMMENTS SUPER - - 1 -1 W- CLOUD - - 1 0 GLUON 1 2 1/36 ½ - 1/3 BOTTOM 2 3 1/18 ½ - 1 TAU 3 4 1/12 ½ - 1/3 STRANGE 4 5 1/9 ½ - 1 MUON OUR 5 6 5/36 ½ - 1/3 DOWN...
  16. suyver

    Standard Model: Lagrangian vs. Hamiltonian

    I was wondering: why is the SM always written with a Lagrangian? Couldn't you just as well write it with a Hamiltonian? The way I understand, the Lagrangian gives me the kinetic energy minus the potential energy (basically a measure for the "free energy", though not in the thermodynamical...
  17. arivero

    Standard Model as TOE? Arguments Against & Need for More Particles

    Which are the arguments against considering the possibility of the Standard Model as a TOE. Why do we need more particles or more degrees of freedom? It lacks, of course, a mechanism to get the SM from geometric considerations, or to get geometry from the SM. But it is almost a minor nuissance.
  18. suyver

    Introduction to Standard Model: presentation(s) requested

    Hi all, I have been asked to give an informal presentation on the Standard Model to some chemists (note that this is not really my field of expertise ). I was wondering if there are some good (powerpoint) presentations out there that I could use to base mine on. That would save me a lot of...
  19. D

    Looking for good overview (book or paper) of standard model

    Hi all, I've decided to read up on particle physics in my spare time for my own edification, but I've had some trouble locating a good textbook/survey paper with a succinct, technical and up-to-date description of the standard model. The text or two that i do have on hand were published in the...
  20. wolram

    Contradicting Physics Beyond the Standard Model

    http://www.lns.cornell.edu/spr/2003-10/msg0055587.html I think its a stroke of good luck that the SSC was canceled since otherwise it might have produced data that contradicted all the physics beyond the Standard Model that physicists now take for granted, and we would have to throw out...
  21. marcus

    Noncommutative geometry and the standard model

    I hate to risk additional distraction when we have so much thoughtful discussion---and add an additional thread when there are several good ones going, but I just came across a 15 October post at arxiv which I want to pass along, should anyone be interested. It is an 11-page article...
  22. S

    Standard Model from Intersecting Branes?

    This is currently a hot topic, and I hope to get some discussion of it from our resident experts on stringy subjects. To start off here's a recent paper, maybe not the greatest but typical and fairly wide-ranging. If you know a better one, or a turorial on the subject why not favor us with a...
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