CERN - The Large Hadron Collider
The Large Hadron Collider (LHC) is the world's largest and highest-energy particle accelerator. It was built by the European Organization for Nuclear Research (CERN) from 1998 to 2008, with the aim of allowing physicists to test the predictions of different theories of particle physics and high-energy physics, and particularly that of the existence of the hypothesized Higgs Boson and of the large family of new particles predicted by super symmetry. The LHC is expected to address some of the most fundamental questions of physics, advancing the understanding of the deepest laws of nature. It contains six detectors each designed for specific kinds of exploration.
The LHC lies in a tunnel 27 kilometres (17 mi) in circumference, as deep as 175 metres (574 ft) beneath the Franco-Swiss border near Geneva, Switzerland. Its synchrotron is designed to collide opposing particle beams of either protons at up to 7 teraelectronvolts (7 TeV or 1.12 microjoules) per nucleon, or lead nuclei at an energy of 574 TeV (92.0 µJ) per nucleus (2.76 TeV per nucleon-pair). It was built in collaboration with over 10,000 scientists and engineers from over 100 countries, as well as hundreds of universities and laboratories.
On 10 September 2008, the proton beams were successfully circulated in the main ring of the LHC for the first time, but 9 days later operations were halted due to a magnet quench incident resulting from an electrical fault. The ensuing Helium gas explosion damaged over 50 superconducting magnets and their mountings, and contaminated the vacuum pipe. On 20 November 2009 proton beams were successfully circulated again, with the first recorded proton–proton collisions occurring 3 days later at the injection energy of 450 GeV per beam. On 30 March 2010, the first collisions took place between two 3.5 TeV beams, setting the current world record for the highest-energy man-made particle collisions, and the LHC began its planned research program.
The LHC will operate at 4 TeV per beam until the end of 2012, 0.5 TeV higher than in 2010 and 2011. It will then go into shutdown for 20 months for upgrades to allow full energy operation (7 TeV per beam), with reopening planned for late 2014.
A hypothetical particle that might be responsible for mass of a partial and thus of all matter.
It exists for only a tiny fraction of a second before breaking up into other particles—so quickly that it cannot be directly detected—and can be detected only by identifying the results of its immediate decay and analyzing them to show they were probably created by a Higgs boson and not some other reason.
Well, when you invest 10 billion dollars you have to find something. Illusory finding of the elusive. Moreover, there is still a missing link. The finding is not yet confirmed.
The Higgs boson is a hypothetical particle, a boson, that is the quantum of the Higgs field. The field and the particle provide a testable hypothesis for the origin of mass in elementary particles. In popular culture, the Higgs boson is also called the God particle, after the title of Nobel physicist Leon Lederman’s The God Particle: If the Universe Is the Answer, What Is the Question? (1993), which contained the author’s assertion that the discovery of the particle is crucial to a final understanding of the structure of matter.
The existence of the Higgs boson was predicted in 1964 to explain the Higgs mechanism—the mechanism by which elementary particles are given mass. While the Higgs mechanism is considered confirmed to exist, the boson itself—a cornerstone of the leading theory—had not been observed and its existence was unconfirmed. Its tentative discovery in 2012 may validate the Standard Model as essentially correct, as it is the final elementary particle predicted and required by the Standard Model which has not yet been observed via particle physics experiments. Alternative sources of the Higgs mechanism that do not need the Higgs boson also are possible and would be considered if the existence of the Higgs boson were to be ruled out. They are known as Higgsless models.
The Higgs boson is named after Peter Higgs, who was one of six authors in the 1960s who wrote the ground-breaking papers covering what is now known as the Higgs mechanism and described the related Higgs Field and boson. Technically, it is the quantum excitation of the Higgs field, and the non-zero value of the ground state of this field gives mass to the other elementary particles such as quarks and electrons through the Higgs mechanism. The Standard Model completely fixes the properties of the Higgs boson, except for its mass. It is expected to have no spin and no electric or color charge, and it interacts with other particles through the weak interaction and Yukawa-type interactions between the various fermions and the Higgs field.
Because the Higgs boson is a very massive particle and decays almost immediately when created, only a very high energy particle accelerator can observe and record it. Experiments to confirm and determine the nature of the Higgs boson using the Large Hadron Collider (LHC) at CERN began in early 2010, and were performed at Fermilab's Tevatron until its close in late 2011. Mathematical consistency of the Standard Model requires that any mechanism capable of generating the masses of elementary particles become visible at energies above 1.4 TeV; therefore, the LHC (designed to collide two 7 TeV proton beams, but currently running at 4 TeV each) was built to answer the question of whether or not the Higgs boson exists.
On 4 July 2012, the two main experiments at the LHC (ATLAS and CMS) both reported independently the confirmed existence of a previously unknown particle with a mass of about 125 GeV/c2 (about 133 proton masses, on the order of 10-25 kg), which is "consistent with the Higgs boson" and widely believed to be the Higgs boson. They acknowledged that further work would be needed to confirm that it is indeed the Higgs boson and not some other previously unknown particle (meaning that it has the theoretically predicted properties of the Higgs boson) and, if so, to determine which version of the Standard Model it best supports.