The photon (carrier of electromagnetism) is one of two known gauge bosons that are both believed to be massless; the other is the gluon (carrier of the strong force). The only other confirmed gauge bosons are the W and Z bosons, which are known from experiment to be extremely massive. Of these, only the photon has been experimentally confirmed to be massless.
Although there are compelling theoretical reasons to believe that gluons are massless, they can never be observed as free particles due to being confined within hadrons, and hence their presumed lack of rest mass cannot be confirmed by any feasible experiment.[1][2]
Hypothetical gravitonedit
The graviton is a hypothetical tensor boson proposed to be the carrier of gravitational force in some quantum theories of gravity, but no such theory has been successfully incorporated into the Standard Model, so the Standard Model neither predicts any such particle nor requires it, and no gravitational quantum particle has been indicated by experiment. Whether or not a graviton would be massless if it existed is likewise an open question.
Quasiparticlesedit
The Weyl fermion discovered in 2015 is also expected to be massless,[3][4] but these are not actual particles. At one time neutrinos were thought to perhaps be Weyl fermions, but when they were discovered to have mass, that left no fundamental particles of the Weyl type.
The Weyl fermions discovered in 2015 are merely quasiparticles – composite motions found in the structure of molecular latices that have particle-like behavior, but are not themselves real particles. Weyl fermions in matter are like phonons, which are also quasiparticles. No real particle that is a Weyl fermion has been found to exist, and there is no compelling theoretical reason that requires them to exist.
massless, particle, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers, books, scholar, jstor, april, . This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Massless particle news newspapers books scholar JSTOR April 2022 Learn how and when to remove this template message In particle physics a massless particle is an elementary particle whose invariant mass is zero At present the only confirmed massless particle is the photon Contents 1 Other particles and quasiparticles 1 1 Standard Model gauge bosons 1 2 Hypothetical graviton 1 3 Quasiparticles 2 References 3 See alsoOther particles and quasiparticles editName Symbol Antiparticle Charge e Spin Interaction mediated ExistencePhoton g Self 0 1 Electromagnetism Confirmed masslessGluon g Self 0 1 Strong interaction Confirmed to exist masslessness unconfirmedGraviton G Self 0 2 Gravitation Purely hypothetical unconfirmedStandard Model gauge bosons edit The photon carrier of electromagnetism is one of two known gauge bosons that are both believed to be massless the other is the gluon carrier of the strong force The only other confirmed gauge bosons are the W and Z bosons which are known from experiment to be extremely massive Of these only the photon has been experimentally confirmed to be massless Although there are compelling theoretical reasons to believe that gluons are massless they can never be observed as free particles due to being confined within hadrons and hence their presumed lack of rest mass cannot be confirmed by any feasible experiment 1 2 Hypothetical graviton edit The graviton is a hypothetical tensor boson proposed to be the carrier of gravitational force in some quantum theories of gravity but no such theory has been successfully incorporated into the Standard Model so the Standard Model neither predicts any such particle nor requires it and no gravitational quantum particle has been indicated by experiment Whether or not a graviton would be massless if it existed is likewise an open question Quasiparticles edit The Weyl fermion discovered in 2015 is also expected to be massless 3 4 but these are not actual particles At one time neutrinos were thought to perhaps be Weyl fermions but when they were discovered to have mass that left no fundamental particles of the Weyl type The Weyl fermions discovered in 2015 are merely quasiparticles composite motions found in the structure of molecular latices that have particle like behavior but are not themselves real particles Weyl fermions in matter are like phonons which are also quasiparticles No real particle that is a Weyl fermion has been found to exist and there is no compelling theoretical reason that requires them to exist Neutrinos were originally thought to be massless and possibly Weyl fermions However because neutrinos change flavour as they travel at least two of the types of neutrinos must have mass and cannot be Weyl fermions 5 The discovery of this phenomenon known as neutrino oscillation led to Canadian scientist Arthur B McDonald and Japanese scientist Takaaki Kajita sharing the 2015 Nobel prize in physics 6 References edit Valencia G 1992 Anomalous gauge boson couplings at hadron supercolliders AIP Conference Proceedings 272 2 1572 1577 arXiv hep ph 9209237 Bibcode 1992AIPC 272 1572V doi 10 1063 1 43410 S2CID 18917295 Debrescu B A 2005 Massless gauge bosons other than the photon Physical Review Letters 94 15 151802 arXiv hep ph 0411004 Bibcode 2005PhRvL 94o1802D doi 10 1103 PhysRevLett 94 151802 PMID 15904133 S2CID 7123874 After 85 year search massless particle with promise for next generation electronics found phys org Princeton University 16 July 2015 Su Yang Xu Ilya Belopolski Nasser Alidoust Madhab Neupane et al 16 July 2015 Discovery of a Weyl fermion semimetal and topological Fermi arcs Science 349 6248 AAAS 613 617 arXiv 1502 03807 Bibcode 2015Sci 349 613X doi 10 1126 science aaa9297 PMID 26184916 S2CID 206636457 Retrieved 2023 11 14 Garisto Robert 1 September 1998 Neutrinos have mass Focus aps org Physical Review Letters American Physical Society Retrieved 2023 11 14 Day Charles 2015 10 07 Takaaki Kajita and Arthur McDonald share 2015 Physics Nobel Physics Today doi 10 1063 PT 5 7208 ISSN 0031 9228 See also editRelativistic particle Gravitational waves Retrieved from https en wikipedia org w index php title Massless particle amp oldid 1205924673, wikipedia, wiki, book, books, library,
