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The safety of high energy particle collisions was a topic of widespread discussion and topical interest during the time when the Relativistic Heavy Ion Collider (RHIC) and later the Large Hadron Collider (LHC)—currently the world's largest and most powerful particle accelerator—were being constructed and commissioned. Concerns arose that such high energy experiments—designed to produce novel particles and forms of matter—had the potential to create harmful states of matter or even doomsday scenarios. Claims escalated as commissioning of the LHC drew closer, around 2008–2010. The claimed dangers included the production of stable micro black holes and the creation of hypothetical particles called strangelets,〔 and these questions were explored in the media, on the Internet and at times through the courts. To address these concerns in the context of the LHC, CERN mandated a group of independent scientists to review these scenarios. In a report issued in 2003, they concluded that, like current particle experiments such as the Relativistic Heavy Ion Collider (RHIC), the LHC particle collisions pose no conceivable threat.〔Blaizot JP, Iliopoulos J, Madsen J, Ross GG, Sonderegger P, Specht HJ (2003). ''(Study of Potentially Dangerous Events During Heavy-Ion Collisions at the LHC )'' (PDF, 176 KiB). CERN. Geneva. (CERN-2003-001 ).〕 A second review of the evidence commissioned by CERN was released in 2008. The report, prepared by a group of physicists affiliated to CERN but not involved in the LHC experiments, reaffirmed the safety of the LHC collisions in light of further research conducted since the 2003 assessment.〔Ellis J, Giudice G, Mangano ML, Tkachev I, Wiedemann U (LHC Safety Assessment Group) (5 September 2008). "(Review of the Safety of LHC Collisions )" (PDF, 586 KiB). 'Journal of Physics G: Nuclear and Particle Physics''. 35, 115004 (18pp). . . (CERN record ).〕〔"(The safety of the LHC )". CERN 2008 (CERN website).〕 It was reviewed and endorsed by a CERN committee of 20 external scientists and by the Executive Committee of the Division of Particles & Fields of the American Physical Society,〔CERN Scientific Policy Committee (2008). ''(SPC Report on LSAG Documents )''. (CERN record ).〕〔"(Statement by the Executive Committee of the DPF on the Safety of Collisions at the Large Hadron Collider )" (PDF, 40 KiB) issued by the (Division of Particles & Fields ) (DPF) of the American Physical Society (APS)〕 and was later published in the peer-reviewed ''Journal of Physics G'' by the UK Institute of Physics, which also endorsed its conclusions.〔〔"(LHC switch-on fears are completely unfounded )". The Institute of Physics. PR 48 (08). 5 September 2008.〕 The report ruled out any doomsday scenario at the LHC, noting that the physical conditions and collision events which exist in the LHC, RHIC and other experiments occur naturally and routinely in the universe without hazardous consequences,〔 including ultra-high-energy cosmic rays observed to impact Earth with energies far higher than those in any man-made collider. ==Background== Particle colliders are a type of particle accelerator used by physicists as a research tool to understand fundamental aspects of the universe. Their operation involves directed beams of particles accelerated to very high kinetic energy and allowed to collide; analysis of the byproducts of these collisions gives scientists good evidence of the structure of the subatomic world and the laws of nature governing it. These may become apparent only at high energies and for tiny periods of time, and therefore may be hard or impossible to study in other ways. Because of the high energy levels involved, concerns have arisen at times in the public arena as to whether such collisions are safe, or whether they might, by reason of their extreme energy, trigger unforeseen problems or consequences. 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「Safety of high-energy particle collision experiments」の詳細全文を読む スポンサード リンク
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