Particle physicists had been waiting for this day for more than two decades. 26 years after the LHC program began, conducted its first successful particle collisions . Its a great day to be a particle physicist, said CERN Director General Rolf Heuer in a stement. A lot of people have waited a long time for this moment, but their patience and dedication is starting to pay dividends.
With these record-shattering collision energies, the LHC experiments are propelled into a vast region to explore, and the hunt begins for dark matter, new forces, new dimensions and the Higgs boson, said Fabiola Gianotti, spokesman for the LHC leading Atlas experiment. The fact that the experiments have published papers already on the basis of last years data bodes very well for this first physics run.
So, how much is 7 TeV, which is calculated by the combined energy of 3.5 TeV for the proton and anti-proton beam? 1 eV is equal to the amount of kinetic energy gained by a single unbound electron when it accelerates through an electric potential difference of one volt. In plain numbers, 1 eV equals 1.602176487(40)×10−19 Joules. In comparison, a single molecule floating in air has the energy of 0.04 eV.
Apply these energy levels to particle beams, however, and you see the enormous dimensions of the LHC. To get the LHC to its maximum collision energy of 14 TeV, particle beams are travelling in bunches of 3000 or about 1 billion particles at a speed of 670,616,429 mph or about 99.9% of the speed of light. The beam will travel through the 27 km (17 mile) LHC ring structure consisting of a pipe that runs through 1746 magnets (1232 dipoles and 514 quadrupoles, located 150 450 ft below the surface) 11,745 times per second. The energy level of each beam at 7 TeV is comparable to an average car that is travelling at 1000 mph. If you intended to build your own LHC, you would need 2.3 trillion flat 3 volt batteries to achieve the same particle beam energy level.
In fact, the energy created is difficult to understand and to control. When I visited the Tevatron in August 2007, which has been conducting particle collisions outside Batavia, IL at energy levels of close to 1.8 TeV, the system had just recovered from a beam loss, which saw a 0.98 TeV particle beam burn through 5 ft of solid steel within 16 ns. In the LHC, collisions are believed to create conditions that are more than 100,000 times hotter than the heart of the Sun.
Physicists hope that this will be enough to melt protons and neutrons to freeing the quarks from their bonds with gluons. In theory, the result would be a state of matter called quark-gluon plasma, which is believed to have existed just after the Big Bang when the Universe. Ultimately, scientists hope that the experiments will shake out the Higgs Boson, which is the only standard model particle that has not been observed yet. An experimental detection of the Higgs boson is likely to lead to the explanation of the origin of mass in the universe.
The LHC runs six detector experiments, including ATLAS, which chases the Higgs Boson; ALICE plans to study the quark-gluon plasma; CMS creates a magnetic field of 4 teslas, about 100 000 times that of the Earth; LHCb aims to explain why we live in a Universe that appears to be composed almost entirely of matter, but no antimatter by investigating the slight differences between matter and antimatter by studying a type of particle called the beauty quark, or b quark.
In the past, the LHC has fueled fears on uncontrollable chain reactions that turn the collider into a ticking time bomb and threaten the existence of earth. For example, some speculated that the collider could produce dangerous cosmic rays, black holes, strangelets, vacuum bubbles and magnetic monopoles.
However, the LHC team dismissed all concerns, stating that nature is consistently creating cosmic rays on earth without any visible effects, microscopic black holes at the LHC refer to particles produced in the collisions of pairs of protons, each of which has an energy comparable to that of a mosquito in flight and astronomic black holes are much heavier than those that could be produced at the LHC. Also, the creation of strangelets and vacuum bubbles is dismissed as purely hypothetical at this point and speculation about the creation of magnetic monopoles indicates that such monopoles would be too heavy to be produced at the LHC.
