http://news.nationalgeographic.com/news ... -big-bang/
Pretty much a fluffy news story, but current as of 3/5/2010
LHC running at 2 x 3.5 TeV
From that link; "The current schedule calls for operating the machine at a level that would result in collisions with the energy of 7 TeV (3.5 TeV per beam)"
Can someone explain this? Maybe its a relativistic thing, but surely two 3.5TeV beams make a 14TeV collision, or a 7TeV collision is formed from two 1.75TeV beams?
(Energy is velocity squared [at Newtonian speeds, hence my question - can't be bothered to run the maths]. Two times a given relative velocity (viz. equiv to a given energy) is therefore 4 times energy.
Can someone explain this? Maybe its a relativistic thing, but surely two 3.5TeV beams make a 14TeV collision, or a 7TeV collision is formed from two 1.75TeV beams?
(Energy is velocity squared [at Newtonian speeds, hence my question - can't be bothered to run the maths]. Two times a given relative velocity (viz. equiv to a given energy) is therefore 4 times energy.
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blaisepascal
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TeV is a measurement of energy, not velocity. Two beams with 3.5TeV each will collide with a total energy of 7TeV, not 14TeV. Where would the remaining 7TeV come from?chrismb wrote:From that link; "The current schedule calls for operating the machine at a level that would result in collisions with the energy of 7 TeV (3.5 TeV per beam)"
Can someone explain this? Maybe its a relativistic thing, but surely two 3.5TeV beams make a 14TeV collision, or a 7TeV collision is formed from two 1.75TeV beams?
(Energy is velocity squared [at Newtonian speeds, hence my question - can't be bothered to run the maths]. Two times a given relative velocity (viz. equiv to a given energy) is therefore 4 times energy.
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Art Carlson
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A collision between two protons, each with energy E and moving in opposite directions, will involve an energy 2E in the center-of-mass frame (which is the lab frame in that case). A collision between a proton moving with energy E and a stationary proton will have total energy E/2 in the center-of-mass frame ( (v/2)^2+(v/2)^2=(v^2)/2 ). In the first case, the full energy of the particles is available (like a head-on car crash). In the second, only half the energy from the lab frame in available in the center-of-mass frame (like a rear-ender, in which both cars end up sliding away at half speed).
Ah, OK, CoM always takes me a moment to adjust my inertial frame(!).
A beam of 3.5TeV protons would provide [up to] a 1.75TeV collision energy into a stationary target or a 7TeV collision energy into the same as itself, but oncoming wrt lab frame.
[I always forget that physicists calculate around lab frame energies (which is then inconsistent as it depends on what the target is doing, as in this case) rather than collision energies like astrophysicists do.]
Still not sure about the relativistic effects though. I will do a calc [later] and ask you to correct it....
A beam of 3.5TeV protons would provide [up to] a 1.75TeV collision energy into a stationary target or a 7TeV collision energy into the same as itself, but oncoming wrt lab frame.
[I always forget that physicists calculate around lab frame energies (which is then inconsistent as it depends on what the target is doing, as in this case) rather than collision energies like astrophysicists do.]
Still not sure about the relativistic effects though. I will do a calc [later] and ask you to correct it....
In the linked press release, CERN announced that the LHC will run with a beam energy of 4 TeV this year.
http://press.web.cern.ch/press/PressRel ... 1.12E.html
They are increasing the power by 0.5 TeV in order to collect enough data to conclude the search for the Higgs boson this year. They are teased by current results and want a conclusion before the 20 month shutdown planned for the end of this year.
http://press.web.cern.ch/press/PressRel ... 1.12E.html
They are increasing the power by 0.5 TeV in order to collect enough data to conclude the search for the Higgs boson this year. They are teased by current results and want a conclusion before the 20 month shutdown planned for the end of this year.
The LHC’s excellent performance in 2010 and 2011 has brought tantalising hints of new physics, notably narrowing the range of masses available to the Higgs particle to a window of just 16 GeV. Within this window, both the ATLAS and CMS experiments have seen hints that a Higgs might exist in the mass range 124-126 GeV. However, to turn those hints into a discovery, or to rule out the Standard Model Higgs particle altogether, requires one more year’s worth of data.
Aero
This is why necromancy is bad. You see people you haven't seen in a while, forget what the date is, and next thing you know ... Zombie Apocalypse!Skipjack wrote:Sorry guys, I was so happy to see Art and Chris too until I realized that their posts were from 2010...
Even if I don't think they'll find the Higgs, it will definitely be interesting to find out what they do find with their experiments when done.
