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The Y(4140) particle is an electrically neutral particle that is about 4.4 times heavier than the proton. It was observed at Fermilab and announced on 17 March 2009.〔 〕 This particle is extremely rare and was detected in only 20 of billions of collisions.〔 〕 Since it decays into J/ψ and φ mesons, it has been suggested that this particle is composed of charm quarks and charm antiquarks, possibly even a four quark combination.〔 〕 The existence of the particle has been confirmed by members of the CMS collaboration at the Large Hadron Collider on November 14, 2012〔Riesselmann, Kurt (December 4, 2012). ("Experiment confirms existence of odd particle" ). Phys.Org.〕〔Hidalgo-Duquea, C., Nievesa, J., Pavón Valderrama, M. (November 29, 2012). ("Heavy Quark Spin Symmetry and SU(3)-Flavour Partners of the X(3872)" ).〕 and by the DØ experiment at the Tevatron on September 25, 2013.〔Dorigo, Tommaso (September 26, 2013). ("DZERO Confirms The Y(4140) And Its Excitation" )〕〔D0 Collaboration (September 25, 2013). ("Search for the X(4140) state in B+->J/psi phi K+ decays with the D0 detector" )〕 The Belle experiment and LHCb〔LHCb Collaboration (February 23, 2012). ("Search for the X(4140) state in B+ to J/psi phi K+ decays" )〕〔Dorigo, Tommaso (February 11, 2013). ("The Mysterious Y(4140)" )〕 have searched for this particle but found no evidence for its existence. The Particle Data Group has renamed Y(4140) to follow naming conventions to X(4140). ==See also== *X(3872) *Zc(3900) *Z(4430) 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Y(4140)」の詳細全文を読む スポンサード リンク
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