جسيم دون ذري

الجسيمات دون الذرية هي التي تكون ذات أحجام أصغر من الذرّة من هذه الجسيمات البروتونات والالكترونات والنيترونات التي منها تتكون الذرة كما إن منها جسيمات أخرى تنتج من التفاعلات النووية لكنها غير مستقرة إذ سرعان ما تتلاشى على هيئة جسيمات أخرى أو طاقة إشعاعية وقسم العلماء الجسيمات دون الذرية إلى ثلاثة أقسام رئيسية اللپتونات والكواركات والپوزونات هذه الأنواع تمثل الجسيمات الأولية أي التي لم يثبت حتى الآن إنها تتكون من جسيمات اصغر منها ولكنها قد تدخل في تكوين جسيمات أخرى فالكواركات مثلاً هي الجسيمات التي يتكون منها كل من الپروتون والنيوترون أما الإلكترون فهو من اللپتونات.^[1]

إن حجم الجسيمات الأولية أصغر بمقدار مئة مليون مرة من حجم الذرات وبعضها عمره قصير جداً يصل إلى أجزاء من الثانية.^[2]

التاريخ

The term "subatomic particle" is largely a retronym of the 1960s, used to distinguish a large number of baryons and mesons (which comprise hadrons) from particles that are now thought to be truly elementary. Before that hadrons were usually classified as "elementary" because their composition was unknown.

فيما يلي قائمة للاكتشافات الهامة:

Particle	Composition	Theorized	Discovered	Comments
Electron e−	elementary (lepton)	G. Johnstone Stoney (1874)	J. J. Thomson (1897)	Minimum unit of electrical charge, for which Stoney suggested the name in 1891.^[3]
alpha particle α	composite (atomic nucleus)	never	Ernest Rutherford (1899)	Proven by Rutherford and Thomas Royds in 1907 to be helium nuclei.
Photon γ	elementary (quantum)	Max Planck (1900) Albert Einstein (1905)	Ernest Rutherford (1899) as γ rays	Necessary to solve the thermodynamic problem of black-body radiation.
Proton p	composite (baryon)	long ago	Ernest Rutherford (1919, named 1920)	The nucleus of 1H.
Neutron n	composite (baryon)	Ernest Rutherford (ح.1918)	James Chadwick (1932)	The second nucleon.
Antiparticles		Paul Dirac (1928)	Carl D. Anderson (e+, 1932)	Revised explanation uses CPT symmetry.
Pions π	composite (mesons)	Hideki Yukawa (1935)	César Lattes, Giuseppe Occhialini (1947) and Cecil Powell	Explains the nuclear force between nucleons. The first meson (by modern definition) to be discovered.
Muon μ−	elementary (lepton)	never	Carl D. Anderson (1936)	Called a "meson" at first; but today classed as a lepton.
Kaons K	composite (mesons)	never	1947	Discovered in cosmic rays. The first strange particle.
Lambda baryons Λ	composite (baryons)	never	University of Melbourne (Λ0, 1950)^[4]	The first hyperon discovered.
Neutrino ν	elementary (lepton)	Wolfgang Pauli (1930), named by Enrico Fermi	Clyde Cowan, Frederick Reines (ν e, 1956)	Solved the problem of energy spectrum of beta decay.
Quarks (u, d, s)	elementary	Murray Gell-Mann, George Zweig (1964)	No particular confirmation event for the quark model.
charm quark c	elementary (quark)	1970	1974
bottom quark b	elementary (quark)	1973	1977
Weak gauge bosons	elementary (quantum)	Glashow, Weinberg, Salam (1968)	CERN (1983)	Properties verified through the 1990s.
top quark t	elementary (quark)	1973	1995	Does not hadronize, but is necessary to complete the Standard Model.
Higgs boson	elementary (quantum)	Peter Higgs et al. (1964)	CERN (2012)	Thought to be confirmed in 2013. More evidence found in 2014.^[5]
Tetraquark	composite	?	Z_c(3900), 2013, yet to be confirmed as a tetraquark	A new class of hadrons.
Pentaquark	composite	?	Yet another class of hadrons. اعتبارا من 2019^[تحديث] several are thought to exist.
Graviton	elementary (quantum)	Albert Einstein (1916)		Interpretation of a gravitational wave as particles is controversial.
Magnetic monopole	elementary (unclassified)	Paul Dirac (1931)	undiscovered

انظر أيضاً

مراجع

^ "Subatomic particles". NTD. Retrieved 5 June 2012. {{cite web}}: Unknown parameter |تاريخ الأرشيف= ignored (help); Unknown parameter |مسار الأرشيف= ignored (help)
^ Heisenberg, W. (1927), "Über den anschaulichen Inhalt der quantentheoretischen Kinematik und Mechanik" (in de), Zeitschrift für Physik 43 (3–4): 172–198, doi:10.1007/BF01397280, Bibcode: 1927ZPhy...43..172H.
^ Klemperer, Otto (1959). "Electron physics: The physics of the free electron". Physics Today. 13 (6): 64–66. Bibcode:1960PhT....13R..64K. doi:10.1063/1.3057011.
^ Some sources such as "The Strange Quark". indicate 1947.
^ "CERN experiments report new Higgs boson measurements". cern.ch. 23 June 2014.

للاستزادة

للقارئ العام

Feynman, R.P. & Weinberg, S. (1987). Elementary Particles and the Laws of Physics: The 1986 Dirac Memorial Lectures. Cambridge Univ. Press.
Brian Greene (1999). The Elegant Universe. W.W. Norton & Company. ISBN 978-0-393-05858-1.
Oerter, Robert (2006). The Theory of Almost Everything: The Standard Model, the Unsung Triumph of Modern Physics. Plume.
Schumm, Bruce A. (2004). Deep Down Things: The Breathtaking Beauty of Particle Physics. Johns Hopkins University Press. ISBN 0-8018-7971-X.
Martinus Veltman (2003). Facts and Mysteries in Elementary Particle Physics. World Scientific. ISBN 978-981-238-149-1.

كتب دراسية

Coughlan, G.D., J.E. Dodd, and B.M. Gripaios (2006). The Ideas of Particle Physics: An Introduction for Scientists, 3rd ed. Cambridge Univ. Press. An undergraduate text for those not majoring in physics.
Griffiths, David J. (1987). Introduction to Elementary Particles. John Wiley & Sons. ISBN 978-0-471-60386-3.
Kane, Gordon L. (1987). Modern Elementary Particle Physics. Perseus Books. ISBN 978-0-201-11749-3.

وصلات خارجية

[1] "Subatomic particles". NTD. Retrieved 5 June 2012. {{cite web}}: Unknown parameter |تاريخ الأرشيف= ignored (help); Unknown parameter |مسار الأرشيف= ignored (help)

[2] Heisenberg, W. (1927), "Über den anschaulichen Inhalt der quantentheoretischen Kinematik und Mechanik" (in de), Zeitschrift für Physik 43 (3–4): 172–198, doi:10.1007/BF01397280, Bibcode: 1927ZPhy...43..172H.

[3] Klemperer, Otto (1959). "Electron physics: The physics of the free electron". Physics Today. 13 (6): 64–66. Bibcode:1960PhT....13R..64K. doi:10.1063/1.3057011.

[4] Some sources such as "The Strange Quark". indicate 1947.

[5] "CERN experiments report new Higgs boson measurements". cern.ch. 23 June 2014.

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