| 词条 | Landau–Yang theorem |
| 释义 |
In quantum mechanics, the Landau–Yang theorem is a selection rule for particles that decay into two on-shell photons. The theorem states that a massive particle with spin 1 cannot decay into two photons.[1][2] AssumptionsA photon here is any particle with spin 1, without mass and without internal degrees of freedom. The photon is the only known particle with these properties. ConsequencesThe theorem has several consequences in particle physics. For example:
Original references1. ^{{Cite journal |first=Chen Ning |last=Yang |authorlink=Chen Ning Yang |title=Selection Rules for the Dematerialization of a Particle into Two Photons |journal=Physical Review |volume=77 |issue=2 |pages=242–245 |year=1950 |url=http://prola.aps.org/abstract/PR/v77/i2/p242_1 |doi=10.1103/PhysRev.77.242|bibcode=1950PhRv...77..242Y}} 2. ^{{Cite journal |first=Lev Davidovich|last=Landau |authorlink=Lev Landau |title=The moment of a 2-photon system |journal=Dokl. Akad. Nauk SSSR |volume=60 |pages=207–209 |year=1948}} 3. ^{{cite web |last = Particle Data Group |url=http://pdg.lbl.gov/2012/tables/rpp2012-tab-mesons-light.pdf |title=Light Unflavored Mesons |accessdate= 4 August 2012}} 4. ^{{cite web |last = ATLAS collaboration |url=http://cdsweb.cern.ch/record/1471031?ln=pt |title=Observation of a New Particle in the Search for the Standard Model Higgs Boson with the ATLAS Detector at the LHC |publisher=Submitted to Phys. Lett. B |accessdate= 4 August 2012}} 5. ^{{cite web |last = CMS collaboration |url=http://cdsweb.cern.ch/record/1471016?ln=pt |title=Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC |publisher=Submitted to Phys. Lett. B |accessdate= 4 August 2012}} Additional references{{Reflist|30em}}{{DEFAULTSORT:Landau-Yang theorem}} 2 : Quantum mechanics|Physics theorems |
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