In particle accelerators, what velocities are achievable? Is there a speed record for the fastest velocity achieved for particles in a particle accelerator? Such as the fastest velocity every achieved for an atom of lead or something? Have any particles ever been accelerated to within a significant percentage of the speed of light such that Einstein’s laws about mass increase becomes measurable?
Anyone have any great book or web site recommendations that discuss experiments and theory relevant to my questions?
Since c is the fastest that things with mass can move, when talking about particle speeds usually the energy is used instead of the speed.
The answer to how fast something goes in a particle accerator is
c - e
where e is some very very small number.
I’m too lazy to actually do the math, so I’ll just point out that the Oh My God particle was going v = 0.9999999999999999999999951 c
As for mass increase, it has absolutely been observed. A charged particle moving through a magnetic field will curve, the amount it curves depends on the mass and energy of the particle. If you look at the tracks in a bubble chamber or other detector, you can calculate the mass of particles, and they act exactly as Einstein says they should.
In addition, short-lived particles such as m particles live longer as observed in the particle detectors due to time-dilation, another of Einsteins predicted (and verified) effects.
The LEP collider at CERN holds the record. LEP reached a center of mass energy of 209 GeV, meaning its electrons and positrons had energies of 104.5 GeV. The corresponding speed: 0.999999999976c.
The Tevatron at the Fermi National Accelerator Laboratory brings protons and antiprotons to even higher energies (1000 GeV), but since these particles are much heavier than LEP’s electrons and positrons, they actually have a lower speed (0.99999912c).
Relativistic effects are measurable at energies well below these extremes. In fact, high energy physicists usually don’t think of relativistsic effects as “effects”. These phenomena are just part of “regular” physics. (It is actually rare that a high energy physicist does a particle-related calculation that does not involve relativistic formulae.)
Quick question/hijack about the Oh-My-God particle…
The link described it as having the energy of a brick falling on your toe. Is this an accurate description of what would happen if that particle hit, say, a human body? A rude bump and a bruise? Or would the much smaller size of the particle cause breaking of the skin?