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In particle physics, a glueball (or gluonium) is a hypothetical composite particle.〔 * Frank Close and Phillip R. Page, "Glueballs", ''Scientific American'', vol. 279 no. 5 (November 1998) pp. 80–85〕 It consists solely of gluon particles, without valence quarks. Such a state is possible because gluons carry color charge and experience the strong interaction. Glueballs are extremely difficult to identify in particle accelerators, because they mix with ordinary meson states.〔 (Glueball on arxiv.org )〕 Theoretical calculations show that glueballs should exist at energy ranges accessible with current collider technology. However, due to the aforementioned difficulty (among others), they have () so far not been observed and identified with certainty,〔Wolfgang Ochs, "The Status of Glueballs" J.Phys.G: Nuclear and Particle Physics 40, 67 (2013) DOI: 10.1088/0954-3899/40/4/043001 http://arxiv.org/pdf/1301.5183v3.pdf〕 although phenomenological calculations have suggested that an experimentally identified glueball candidate, denoted , has properties consistent with those expected of a Standard Model glueball. The prediction that glueballs exist is one of the most important predictions of the Standard Model of particle physics that has not yet been confirmed experimentally.〔Y.K. Hsiao, C.Q. Geng, "Identifying Glueball at 3.02 GeV in Baryonic B Decays" (Version 2: October 9, 2013) http://arxiv.org/abs/1302.3331〕 ==Properties of glueballs== In principle, it is theoretically possible for all properties of glueballs to be calculated exactly and derived directly from the equations and fundamental physical constants of quantum chromodynamics (QCD) without further experimental input. So, the predicted properties of these hypothetical particles can be described in exquisite detail using only Standard Model physics which have wide acceptance in the theoretical physics literature. But, there is considerable uncertainty in the measurement of some of the relevant key physical constants, and the QCD calculations are so difficult that solutions to these equations are almost always numerical approximations (reached by several very different methodologies). This can lead to variation in theoretical predictions of glueball properties like mass and branching ratios in glueball decays. 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「glueball」の詳細全文を読む スポンサード リンク
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