大型强子对撞机（英语：Large Hadron Collider，缩写：LHC）是一座位于瑞士日内瓦近郊欧洲核子研究组织的对撞型粒子加速器，作为国际高能物理学研究之用。LHC已经建造完成，2008年9月10日开始试运转，并且成功地维持了两质子束在轨道中运行，成为世界上最大的粒子加速器设施。大型强子对撞机是一个国际合作计划，由全球85国中的多个大学与研究机构，逾8,000位物理学家合作兴建，经费一部份来自欧洲核子研究组织会员国提供的年度预算，以及参与实验的研究机构所提拨的资金。

大型强子对撞机本预计于2008年10月21日开始进行低能量对撞实验。但2008年9月19日，大型强子对撞机第三与第四段之间用来冷却超导磁铁的液态氦发生了严重的泄漏，据推测是由于联接两个超导磁铁的接点接触不良，在超导高电流的情况下融毁所造成的。依据欧洲核子研究组织的安全条例，必需将磁铁升回到室温后详细检查才能继续运转，这将需要三到四周的时间。要再冷却回运作温度，也是得经过三四周的时间，如此正好遇上预定的年度检修时程，因此必须延迟开始运作的时间。

The Large Hadron Collider (LHC) is the world's largest and most powerful particle collider, the largest, most complex experimental facility ever built, and the largest single machine in the world. It was built by the European Organization for Nuclear Research (CERN) between 1998 and 2008 in collaboration with over 10,000 scientists and engineers from over 100 countries, as well as hundreds of universities and laboratories. It lies in a tunnel 27 kilometres (17 mi) in circumference, as deep as 175 metres (574 ft) beneath the France–Switzerland border near Geneva, Switzerland. Its first research run took place from 30 March 2010 to 13 February 2013 at an initial energy of 3.5 teraelectronvolts (TeV) per beam (7 TeV total), almost 4 times more than the previous world record for a collider, rising to 4 TeV per beam (8 TeV total) from 2012. On 13 February 2013 the LHC's first run officially ended, and it was shut down for planned upgrades. 'Test' collisions restarted in the upgraded collider on 5 April 2015, reaching 6.5 TeV per beam on 20 May 2015 (13 TeV total, the current world record). Its second research run commenced on schedule, on 3 June 2015.