Symmetry Principles and Conservation Laws in Atomic and ...

GENERAL ARTICLEFigure 6. Computer-generatedimage shows the locationof the 27-km LHC tunnel(in blue) on the Swiss–France border. The fourmain experiments (ALICE,ATLAS,CMS,andLHCb) arelocated in undergroundcaverns connected to thesurface by 50 m to 150 mpits. Part of the pre-accelerationchain is shown ingrey.The centre-of-masscollision energy is14~TeV which is eighttimes greater than theprevious highestenergy collider. Suchenergies have notbeen produced sinceapproximately 10 –25 safter the big bang.Higgs boson of 114 GeV=c 2 with a 95% con¯dence level.The search for the Higgs boson is one of the principalgoals of the largest and the biggest experiment donein the world at the LHC (Large Hadron Collider), a 27km-long particle accelerator built at CERN near Geneva(Figure 6). The LHC stores and collides two beamsof protons which are circulating clockwise and counterclockwiseabout the accelarator [14]. Superconductingdipole magnets generate 8.3 Tesla ¯elds to keep thebeams in orbit. The magnets are cooled to 1.9 K, colderthan outer space, to achieve these ¯elds. The centreof-masscollision energy is 14 TeV which is eight timesgreater than the previous highest energy collider. Suchenergies have not been produced since approximately10 ¡25 s after the big bang.There are three experiments around the LHC which willrecord the particles generated in the proton{proton collisions.Two, ATLAS and CMS, are the largest colliderparticle physics experiments ever built with dimensionsof 46 m £ 25 m £ 25 m and 21 m £ 15 m £ 15 m, respectively.ATLAS and CMS will search for collisions thatcontain Higgs bosons or other exotic phenomena. Thethird experiment for proton{proton collisions is LHCb,which is dedicated to studying beauty quarks that exhibitCP violation in their decay as discussed in Section1.2. There is a fourth experiment, ALICE, which willstudy the strong interaction via events produced whenthe LHC collides gold nuclei together.938 RESONANCE October 2010