Showing posts with label cern. Show all posts
Showing posts with label cern. Show all posts

Tuesday, November 9, 2010

Large Hadron Collider (LHC) generates a 'mini-Big Bang'

      The Large Hadron Collider has successfully created a "mini-Big Bang" by smashing together lead ions instead of protons.
      The scientists working at the enormous machine on Franco-Swiss border achieved the unique conditions on 7 November.
      
      The experiment created temperatures a million times hotter than the centre of the Sun.
    
      The LHC is housed in a 27km-long circular tunnel under the French-Swiss border near Geneva.
Up until now, the world's highest-energy particle accelerator - which is run by the European Organization for Nuclear Research (Cern) - has been colliding protons, in a bid to uncover mysteries of the Universe's formation.
      Proton collisions could help spot the elusive Higgs boson particle and signs of new physical laws, such as a framework called supersymmetry.
      But for the next four weeks, scientists at the LHC will concentrate on analysing the data obtained from the lead ion collisions.
      This way, they hope to learn more about the plasma the Universe was made of a millionth of a second after the Big Bang, 13.7 billion years ago.
      One of the accelerator's experiments, ALICE, has been specifically designed to smash together lead ions, but the ATLAS and Compact Muon Solenoid (CMS) experiments have also switched to the new mode.

Read more: here

Tuesday, September 28, 2010

The Higgs Boson

     When you get on the scale in the morning, you may be hoping that it registers a smaller number than the day before -- you may be hoping that you've lost weight. It's the quantity of mass in you, plus the force of gravity, that determines your weight. But what determines your mass?
     That's one of the most-asked, most-hotly pursued questions in physics today. Many of the experiments circulating in the world's particle accelerators are looking into the mechanism that gives rise to mass. Scientists at CERN, as well as at Fermilab in Illinois, are hoping to find what they call the "Higgs boson." Higgs, they believe, is a particle, or set of particles, that might give others mass.
     The idea of one particle giving another mass is a bit counter-intuitive... Isn't mass an inherent characteristic of matter? If not, how can one entity impart mass on all the others by simply floating by and interacting with them?
     An oft-cited analogy describes it well: Imagine you're at a Hollywood party. The crowd is rather thick, and evenly distributed around the room, chatting. When the big star arrives, the people nearest the door gather around her. As she moves through the party, she attracts the people closest to her, and those she moves away from return to their other conversations. By gathering a fawning cluster of people around her, she's gained momentum, an indication of mass. She's harder to slow down than she would be without the crowd. Once she's stopped, it's harder to get her going again.
     This clustering effect is the Higgs mechanism, postulated by British physicist Peter Higgs in the 1960s. The theory hypothesizes that a sort of lattice, referred to as the Higgs field, fills the universe. This is something like an electromagnetic field, in that it affects the particles that move through it, but it is also related to the physics of solid materials. Scientists know that when an electron passes through a positively charged crystal lattice of atoms (a solid), the electron's mass can increase as much as 40 times. The same might be true in the Higgs field: a particle moving through it creates a little bit of distortion -- like the crowd around the star at the party -- and that lends mass to the particle.

Read more: http://www.exploratorium.edu/origins/cern/ideas/higgs.html