Posted on 08/17/2002 4:50:36 AM PDT by JohnHuang2
Edited on 06/29/2004 7:09:22 PM PDT by Jim Robinson. [history]
No and yes.
First, there is no such thing as negative mass. Antiparticles have exactly the same mass as their matter counterparts. (E=mc², remember, so the fact that matter and antimatter release nonzero energy when they annihilate tells you that their masses can't cancel.)
Now, is there an anti-Higgs? Yes, and it's the Higgs boson! The fundamental bosons--such as the photon--are "self-conjugate", meaning that they are their own anti-particles. [Geek alert: some bosons, such as the W, carry charge, and are not exactly self-conjugate, but both of the charge states are of equal rank: the W+ and the W- have equal claims on being the "matter" particle.]
Personally, I don't think of these "gauge bosons" as matter at all, never mind the fact that some of them are quite massive! I think of them as particles of force. The universe is composed of matter and force, and both are quantized into particles.
In the religious spirit of the threads title, I submit that quarks and leptons are the "nouns" of God's Word, while the gauge bosons are the verbs.
I came to Penn to do SSC development work in August, 1993. The SSC was killed in October, 1993. It represented half of the U.S. effort in experimental high-energy physics. Since then, the "base program" has shrunk by another third, so my field has shrunk by 2/3 in the last decade.
That's not to say that the field is dead; it is just in the process of moving out of the United States. Upon the cancellation of the SSC, many physicists turned to work on the LHC, a competing machine being built in Geneva. It should see first collisions in 2008.
There is no possibility of reviving the SSC. The incomplete tunnel has been filled in and the laboratory dismantled. Fermilab will own the energy frontier for another six years, but after that the future of physics lies in Europe.
Not necessarily. There are a couple of models of the very early universe, and all of them are compatible with the Standard Model of particle physics. (They had better be!)
Guth's idea (inflation) was motivated by a desire to explain the "flatness" problems of cosmology (comprising such apparently unconnected problems as why different parts of the universe look so thermodynamically similar, and why we don't see any magnetic monopoles). The notion that the universe could have arisen out of essentially nothing was a surprising consequence of his solution.
What's the length of a single photon? Pick any energy.
New Scientist article on the last attempt to find the Higgs boson
An interesting Raytheon article putting it in perspective with regard to Cosmology
According to quantum mechanics--and experiment--photons don't have a specific position or energy until you go to measure one of these properties. Each photon has a position distribution (a size, if you will) and an energy distribution (i.e., a frequency spectrum).
Let's say that you measure a photon's position. The more accurately you measure its position--and as far as we are able to measure, real photons can be localized to an arbitrarily small point--the greater becomes the distribution of its energy. The more accurately you measure its energy (frequency), the larger becomes the distribution of its position. The product of these uncertainties is greater than or equal to Planck's constant divided by 2 pi. This relationship is known as the Heisenberg Uncertainty Principle. I want to stress that this principle is a statement about the nature of the properties of the photon and not a consequence of our specific methods of measuring them.
So in answer to your question, a photon's "size", if you want to call it that, depends not on its frequency, but on its spread of frequencies.
[Geek alert: math nerds may understand this wording better: momentum is the Fourier transform of position.]
[Insufferable geek alert: when we go to measure the size of a real photon, the answer, so far as we are able to determine, is that it is pointlike. The story for virtual photons, however, is different. They not only have size, but shape! This is because the virtual photons pull quark-antiquark pairs out of the vacuum. These form little spacetime "loops" with which other virtual photons can interact. The variation of the photon structure function F2 with momentum-transfer-squared is one of the most important experimental tests of quantum chromodynamics (the theory of the strong nuclear force).]
That depends how much energy you're radiating. Each photon has an energy equal to the frequency times Planck's constant. If you know the frequency and know how much energy you've put into the pulse, you can calculate the number of photons in the pulse. One is a perfectly good number; if you want a single photon per pulse, you just have to turn the intensity down to the correct level.
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