Has the Higgs Boson Particle Field Been Hiding in Plain Sight? 163
sciencehabit writes with a link to the ScienceNow site, noting an article saying the Higgs boson may already have been found in previous observations of the known universe. A theorist at Michigan state is arguing that scientists may have already found evidence for the elusive particle. The key appears to be that the particles that make up the Higgs field are of various 'strengths', and some of those particles may tug on others very weakly. "The lightest Higgs can be very light indeed, but it would not have been seen at [CERN's Large Electron-Positron (LEP)], because LEP experimenters were looking for an energetic collision that made a Z that then spit out a Higgs. That wouldn't happen very often if the lightest Higgs and the Z hardly interact. 'Just within the simplest supersymmetric model, there's still room for Higgs that is missed,' Yuan says. However, this lightweight Higgs is not exactly the Higgs everyone is looking for, says Marcela Carena, a theorist at Fermilab. 'The Higgs they are talking about is not the one responsible for giving mass to the W and Z,' she says. It can't be because it hardly interacts with those particles, Carena says. Indeed, in Yuan's model, the role of mass-giver falls to one of the heavier Higgses, which is still heavier than the LEP limit, she notes."
For those that went "wtf?!" (Score:5, Informative)
Re:The Higgs Boson (Score:3, Informative)
Re:Am I missing something? (Score:5, Informative)
Re:The Higgs Boson (Score:5, Informative)
Re:Am I missing something? (Score:3, Informative)
Re:Am I missing something? (Score:3, Informative)
Re:Dear fucking assholes (Slashdot editors) (Score:5, Informative)
Re:Am I missing something? (Score:3, Informative)
No, you're dead on (Score:4, Informative)
Since nobody's made this point yet, I'll put it out there.
The statement is literally correct. Say you have a field in 3-space. That field itself is a 3-vector at every point in that space. When you make a fourier transform of the field, you get the field as a function of a momentum-like 3 vector. That vector is quantized, and the excitations of it are what we refer to as "photons". Add in special relativity, and you have the basics of quantum field theory.
Try the first chapter of Lahiri and Pal's "A First Book of Quantum Field Theory". If you've had undergrad calculus, it shouldn't be that bad.
Re:The Higgs Boson (Score:3, Informative)
The momentum of a charged particle can be measured from the curvature of the particle's trajectory in a magnetic field.
Energy can be determined through various means, which usually have to do with measuring the energy given off when the particle slows down when going through matter. For example, you could have a leaded glass block. As a fast-moving electron goes through the glass, it gives up its kinetic energy as it interacts with the atoms in the block. Eventually the kinetic energy is turned into a proportionate amount of light.
A more unusual technique is to measure the velocity of a charged particle by using the Cerenkov effect.
Re:The Higgs Boson (Score:5, Informative)
Mostly it comes down to conservation of mass/energy. If we know we put 3 electrons and 20GeV of energy into the reaction chamber and got out 2 electrons, 10GeV and one unknown particle then that unknown particle must have a combined mass/energy to balance things out. (Remember that E=mc^2 so mass could have been converted to energy and vice vesa.)
So how did they measure the mass of the first particle? As one of the sibling posts said, put an electrically charged particle into a static electric field and watch how fast the field moves the particle (this can be observed at the macroscopic scale using gas bubble chambers).
Of course the above requires you to know the charge of the particle, so how do we measure the charge of an elementary particle? Simple! Fill the air with neutrally charged oil droplets and "spray" them with the particle. Some droplets will pick up 1 particle and some will pickup 2 or 3 or 4. Put them in a static electric field and measure how strong the field has to be to suspend the droplets against the force of gravity. You don't have to know which ones picked up how many particle, you just have to measure the difference in the required field strength. (See the Oil-drop experiment; note measuring the mass of oil droplets is hard be macroscopically possible.)
So in summary: we measure particle mass in terms of the masses of other particles. The first particle's mass was measured in terms of it's electric charge. The first particle's electric charge was measured in terms of how much force it imparted on an oil droplet. The oil droplet's mass was measured relative to a lump of platinum-iridium sitting in Paris. That lump was just pointed to and called 1 kilogram.
Any questions?
Re:Am I missing something? (Score:5, Informative)
Re:Am I missing something? (Score:4, Informative)
Re:Am I missing something? (Score:2, Informative)
Re:The Higgs Boson (Score:3, Informative)
If you put a particle with known velocity and electrical charge in a known magnetical field, it will run on a circle. You can calculate its mass by the circle's radius.
At particle accelerators the magnetical field there is a given, since you need it to keep the particles inside the building while they are gaining speed.