The Higgs boson is a hypothetical massive scalar elementary particle predicted to exist by the Standard Model of particle physics. In Particle physics, an elementary particle or fundamental particle is a particle not known to have substructure that is it is not known to be made In Particle physics, bosons are particles which obey Bose-Einstein statistics; they are named after Satyendra Nath Bose and Albert Einstein Peter Ware Higgs, FRS, FRSE, (born May 29, 1929) is a British theoretical physicist and an Emeritus professor François Englert (born 6 november 1932 is a Belgian theoretical physicist Robert Brout (1928 is a Belgian Theoretical physicist who has made significant contributions in elementary particle physics Gerald Stanford Guralnik is a professor of Physics at Brown University. Carl Richard Hagen is a Professor of Particle physics at the University of Rochester. Thomas Walter Bannerman Kibble is a senior research investigator at The Blackett Laboratory at Imperial College London, UK In Quantum mechanics, spin is a fundamental property of atomic nuclei, Hadrons and Elementary particles For particles with non-zero spin For the pseudoscientific "scalar field theory" see " Scalar field theory (pseudoscience " In Theoretical physics, In Particle physics, an elementary particle or fundamental particle is a particle not known to have substructure that is it is not known to be made The Standard Model of Particle physics is a theory that describes three of the four known Fundamental interactions together with the Elementary particles Particle physics is a branch of Physics that studies the elementary constituents of Matter and Radiation, and the interactions between them It is the only Standard Model particle not yet observed, but would help explain how otherwise massless elementary particles still manage to construct mass in matter. Mass is a fundamental concept in Physics, roughly corresponding to the Intuitive idea of how much Matter there is in an object In particular, it would explain the difference between the massless photon and the relatively massive W and Z bosons. In Physics, the photon is the Elementary particle responsible for electromagnetic phenomena The W and Z bosons are the Elementary particles that mediate the Weak force. Elementary particle masses, and the differences between electromagnetism (caused by the photon) and the weak force (caused by the W and Z bosons), are critical to many aspects of the structure of microscopic (and hence macroscopic) matter; thus, if it exists, the Higgs boson has an enormous effect on the world around us. Electromagnetism is the Physics of the Electromagnetic field: a field which exerts a Force on particles that possess the property of The weak interaction (often called the weak force or sometimes the weak nuclear force) is one of the four Fundamental interactions of nature

As of May 2008, no experiment has directly detected the existence of the Higgs boson, but this may change as the Large Hadron Collider (LHC) at CERN becomes operational. The European Organization for Nuclear Research (Organisation Européenne pour la Recherche Nucléaire known as CERN The Higgs mechanism, which gives mass to vector bosons, was theorized in 1964 by Peter Higgs,^[1] François Englert and Robert Brout,^[2] working from the ideas of Philip Anderson, and independently by G. S. Guralnik, C. R. Hagen, and T. W. B. Kibble. The Higgs mechanism is Spontaneous symmetry breaking in a Gauge theory. A vector boson is a Boson with spin equal to one unit of \hbar ( Planck's constant divided by 2 \pi Peter Ware Higgs, FRS, FRSE, (born May 29, 1929) is a British theoretical physicist and an Emeritus professor François Englert (born 6 november 1932 is a Belgian theoretical physicist Robert Brout (1928 is a Belgian Theoretical physicist who has made significant contributions in elementary particle physics Philip Warren Anderson (born December 13, 1923) is an American Physicist. Gerald Stanford Guralnik is a professor of Physics at Brown University. Carl Richard Hagen is a Professor of Particle physics at the University of Rochester. Thomas Walter Bannerman Kibble is a senior research investigator at The Blackett Laboratory at Imperial College London, UK ^[3] Higgs proposed that the existence of a massive scalar particle could be a test of the theory, a remark added to his Physical Review letter^[4] at the suggestion of the referee. Physical Review (frequently abbreviated as Phys Rev) is one of the oldest and most-respected Scientific journals publishing research on all aspects of ^[5] Steven Weinberg and Abdus Salam were the first to apply the Higgs mechanism to the electroweak symmetry breaking. Steven Weinberg (born May 3, 1933) is an American Physicist, and Nobel laureate in Physics for his contributions with Abdus Salam Abdus Salam ( Urdu: محمد عبد السلام) ( January 29, 1926; Jhang Punjab &ndash November 21, The Higgs mechanism is Spontaneous symmetry breaking in a Gauge theory. The electroweak theory predicts a neutral particle whose mass is not far from the W and Z bosons.

Theoretical overview

A one-loop Feynman diagram of the first-order correction to the Higgs mass. Motivation and history When calculating Scattering cross sections in Particle physics, the interaction between particles can be described The Higgs boson couples strongly to the top quark so it may decay into top anti-top quark pairs. The top quark is the third- generation up-type Quark with a charge of +(2/3 e.

The Higgs boson particle is one quantum component of the theoretical Higgs Field. In empty space, the Higgs field has an amplitude different from zero. This is also known as a "non-zero vacuum expectation value", and illustrates the concept that there is no such thing as a completely “empty” vacuum. This vacuum means "absence of matter" or "an empty area or space" for the cleaning appliance see Vacuum cleaner. The existence of this non-zero vacuum expectation plays a fundamental role: it gives mass to every elementary particle, including the Higgs boson itself. In particular, the acquisition of a non-zero vacuum expectation value spontaneously breaks electroweak gauge symmetry, which scientists often refer to as the Higgs mechanism. In Particle physics, the electroweak interaction is the unified description of two of the four Fundamental interactions of nature Electromagnetism and the Gauge theory is a peculiar Quantum field theory where the Lagrangian is invariant under certain transformations The Higgs mechanism is Spontaneous symmetry breaking in a Gauge theory. This is the simplest mechanism capable of giving mass to the gauge bosons while remaining compatible with gauge theories. In Particle physics, gauge bosons are Bosonic particles that act as carriers of the fundamental forces of nature Gauge theory is a peculiar Quantum field theory where the Lagrangian is invariant under certain transformations In essence, this field is analogous to a pool of molasses, that “sticks” to the otherwise massless fundamental particles which travel through the field converting into different particles with mass and form the basis of the atom.

In the Standard Model, the Higgs field consists of two neutral and two charged component fields. The Standard Model of Particle physics is a theory that describes three of the four known Fundamental interactions together with the Elementary particles Both of the charged components and one of the neutral fields are Goldstone bosons, which are massless and act as the longitudinal third-polarization components of the massive W⁺, W^-, and Z bosons. In particle and Condensed matter physics, Goldstone bosons (also known as Nambu -Goldstone bosons) are Bosons that appear in models The W and Z bosons are the Elementary particles that mediate the Weak force. The quantum of the remaining neutral component corresponds to the massive Higgs boson. Since the Higgs field is a scalar field, the Higgs boson has no spin and has no intrinsic angular momentum. The Higgs Boson is a hypothetical massive scalar Elementary particle predicted to exist by the Standard Model of Particle physics In Mathematics and Physics, a scalar field associates a scalar value which can be either mathematical in definition or physical, to every point In Quantum mechanics, spin is a fundamental property of atomic nuclei, Hadrons and Elementary particles For particles with non-zero spin In Physics, the angular momentum of a particle about an origin is a vector quantity equal to the mass of the particle multiplied by the Cross product of the position The Higgs boson is also its own antiparticle and is CP-even. to most kinds of particles, there is an associated antiparticle with the same Mass and opposite Electric charge. In Particle physics, CP violation is a violation of the postulated CP symmetry of the laws of physics These various massless energy particles give the three dimensions of mass and fourth dimension of weight when operating under the Higgs field model.

The Standard Model does not predict the value of the Higgs boson mass. If the mass of the Higgs boson is between 115 and 180 GeV, then the Standard Model can be valid at energy scales all the way up to the Planck scale (10¹⁶ TeV). In Particle physics and Physical cosmology, the Planck scale is an Energy scale around 1 Many theorists expect new physics beyond the Standard Model to emerge at the TeV-scale, based on unsatisfactory properties of the Standard Model. In Physics, the Standard Model of Particle physics is currently the best description of all experimental data The highest possible mass scale allowed for the Higgs boson (or some other electroweak symmetry breaking mechanism) is around one TeV; beyond this point, the Standard Model becomes inconsistent without such a mechanism because unitarity is violated in certain scattering processes. The Higgs mechanism is Spontaneous symmetry breaking in a Gauge theory. In Quantum physics, unitarity means that the sum of probabilities of all possible outcome of any event is always 1 Many models of Supersymmetry predict that the lightest Higgs boson (of several) will have a mass only slightly above the current experimental limits, at around 120 GeV or less. MSSM may refer to Maine School of Science and Mathematics Minimal Supersymmetric Standard Model Mount Sinai School

Experimental search

A Feynman diagram of one way the Higgs boson may be produced at the LHC. Motivation and history When calculating Scattering cross sections in Particle physics, the interaction between particles can be described Here, two gluons decay into a top/anti-top pair which then combine to make a neutral Higgs. Gluons ( Glue and the suffix -on) are Elementary particles that cause Quarks to interact and are indirectly responsible for the The top quark is the third- generation up-type Quark with a charge of +(2/3 e.

As of 2008, the Higgs boson has not been observed experimentally, despite large efforts invested in accelerator experiments at CERN and Fermilab. The European Organization for Nuclear Research (Organisation Européenne pour la Recherche Nucléaire known as CERN Fermi National Accelerator Laboratory ( Fermilab) located in Batavia near Chicago, Illinois, is a U The non-observation of clear signals leads to an experimental lower bound for the Standard Model Higgs boson mass of 114. 4 GeV at 95% confidence level. A small number of events were recorded by experiments at LEP collider at CERN that could be interpreted as resulting from Higgs bosons, but the evidence is inconclusive. ^[6] The Large Hadron Collider (LHC), currently under construction at CERN, is expected to be able to confirm or deny the existence of the Higgs boson in most circumstances.

Precision measurements of electroweak observables indicate that the Standard Model Higgs boson mass has an upper bound of 144 GeV at the 95% confidence level^[7] as of March 2007 (incorporating an updated measurement of the top quark and W boson masses). In Particle physics, an oblique correction refers to a particular type of radiative correction to the Electroweak sector of the Standard Model The Standard Model of Particle physics is a theory that describes three of the four known Fundamental interactions together with the Elementary particles The top quark is the third- generation up-type Quark with a charge of +(2/3 e. The W and Z bosons are the Elementary particles that mediate the Weak force. Experiments searching for the Higgs boson are ongoing at the Fermilab Tevatron. Fermi National Accelerator Laboratory ( Fermilab) located in Batavia near Chicago, Illinois, is a U Tevatron is a circular Particle accelerator at the Fermi National Accelerator Laboratory in Batavia Illinois and is the highest energy particle collider The limits on the production cross section of the Higgs boson set by the on-going Tevatron searches are now less than a factor of 1. 5 away from Standard Model predictions in the mass range where the Higgs boson primarily decays to an on-shell W boson and an off-shell W boson. ^[8] There have been optimistic articles about potential evidence of the Higgs Boson,^[9] but no evidence is yet compelling enough to convince the scientific community as a whole.

Alternatives to the Higgs mechanism for electroweak symmetry breaking

Main article: Higgsless model

In the years since the Higgs boson was proposed, there have been several alternative mechanisms to the Higgs mechanism. In Particle physics, a Higgsless model is a model that does not have the Higgs boson, and employs a different mechanism of mass generation and Electroweak All of the alternative mechanisms use strongly interacting dynamics to produce a vacuum expectation value that breaks electroweak symmetry. A partial list of these alternative mechanisms are

• Technicolor^[10] is a class of models that attempts to mimic the dynamics of the strong force as a way of breaking electroweak symmetry. In Physics, technicolor models are theories beyond the Standard Model (sometimes but not always GUTs which do not have a scalar Higgs In particle physics the strong interaction, or strong force, or color force, holds Quarks and Gluons together to form Protons and
• Abbott-Farhi models of composite W and Z vector bosons. ^[11]
• Top quark condensate. In Particle physics, the top quark condensate theory is an alternative to the Standard Model in which a fundamental Scalar Higgs field is replaced

In fiction

Main article: Higgs boson in fiction

Mentions of the Higgs boson (sometimes referred to in popular articles as the 'God particle', after the not-all-serious title of Nobel laureate Leon Lederman's book The God Particle: If the Universe Is the Answer, What Is the Question?), occur in some works of fiction. The Higgs boson has appeared in several works of Fiction in Popular culture. God is the principal or sole Deity in Religions and other belief systems that worship one deity. Leon Max Lederman (born July 15, 1922) is an American Experimental physicist and Nobel Prize in Physics laureate for The God Particle If the Universe Is the Answer What is the Question? is a 1993 Popular science book by Nobel Prize -winning Physicist Leon These references mostly imbue it with fantastic properties, and of the actual theory of the particle only its unknown mass is capitalized upon.

See also

• Yukawa interaction
• List of particles
• Large Hadron Collider

References

Further reading

External links

• At Fermilab, the Race Is on for the 'God Particle'
• Physics World, Introducing the little Higgs
• A quasi-political Explanation of the Higgs Boson
• The Atom Smashers, a blog about the making of a documentary about the search for the Higgs boson
• In CERN Courier, Steven Weinberg reflects on spontaneous symmetry breaking
• Steven Weinberg Praises Teams for Higgs Boson Theory
• Physical Review Letters - 50th Anniversary Milestone Papers
• The God Particle, from National Geographic Magazine