What are the chemical and physical properties of delta particles? When you bombard something with delta particles, does that object become electrically/chemically charged, or does it disintegrate?
What are the chemical and physical prooperties of taus, fermions, bosons, leptons and mesons? What are these eighteen different particles that scientists have claimed to discover, and what are their chemical and physical properties?
How much progress have the physicists at Fermilab made in their quest to dicover gravitons (massless particles)? Who is the other research facility that’s “competing” with Fermilab?
What’s the difference between a photon and a tachion?
I just finished a B.S. in physics and never heard of a delta particle. What context did you hear about it in.
Fermions, leptons, bosons and mesons are overlapping categories of elementry particles. They don’t have chemical properties in the usual sense as chemical properties usually refers to the electrical interactions of atoms and molecules which are much larger then most of the simpler particles you mentioned. Here’s a flow chart you can use to learn the different categories of particles and look up thier physical properties.
A photon is the particle that makes up light and as such travels at light speed. A tachyon is a (very) hypothetical particle that would travel faster then light. I’ll stress that tachyons are, so far as I know, strictly hypothetical and not the result of any observation or theory.
A ? is usually termed a “resonance”. It is a hadron (strongly-interacting particle) consisting of three quarks (the specific ones depending on which ? you mean: there are four). If you fired a stream of them at a target they would interact strongly with the hadrons in the target as outlined in quantum chromodynamics (QCD), assuming they survived the trip (?s are notoriously short-lived).
This has been well answered. Suffice to say, you evidently don’t know enough about the terms to form a semantically valid question.
For one, a photon is a specific kind of particle, while a tachyon is a label which would apply to any particle whose mass-squared is negative, and thus whose field velocity (but not its packet velocity!) is faster than light. Compare to how “electron” denotes a specific kind of particle and “hadron” is a label applied to any particle interacting under the strong nuclear force.
If your undergrad physics program was similar to mine, you probably just learned the fundamental particles of the standard model (plus protons and neutrons, of course.) As Mathocist mentions, [symbol]D[/symbol]'s are hadrons, not fundamental particles. Specifically, they’re L=0, S=3/2 baryon states consisting of up and down quarks. The four types of [symbol]D[/symbol]'s in terms of the flavors of their constituent quarks are:
[symbol]D[/symbol][sup]++[/sup] = u u u
[symbol]D[/symbol][sup]+[/sup] = u u d
[symbol]D[/symbol][sup]0[/sup] = u d d
[symbol]D[/symbol][sup]-[/sup] = d d d
As you can see, [symbol]D[/symbol][sup]+[/sup] and [symbol]D[/symbol][sup]0[/sup] have the same constituent quarks as the proton and neutron, respectively, but different spin (p’s and n’s are S = 1/2 states.)
This has been well answered. Suffice to say, you evidently don’t know enough about the terms to form a semantically valid question.
Look, if you don’t want to answer the guys question, then don’t, but who are you to say that any question is not “semantically valid”? There could easily be someone on here who would like to explain this to someone, so why not just let them do it? And if no one wants to, this post will sink to the bottom.
What is a psion? Are they the same things as psi particles?
As has been mentioned, it’s doesn’t quite work to ask about the chemical properties of a [symbol]D[/symbol], as the chemical properties of a material are determined by electrons surrounding a nucleus. (Asking about the chemical properties of a [symbol]D[/symbol] is akin to asking about the chemical properties of, say, a proton.)
As for other properties of the [symbol]D[/symbol]…
The [symbol]D[/symbol] is actually part of a very large family of composite particles. While there are four different charges that a [symbol]D[/symbol] can have ([symbol]D[/symbol][sup]++[/sup], [symbol]D[/symbol][sup]+[/sup], [symbol]D[/symbol][sup]0[/sup], [symbol]D[/symbol][sup]-[/sup]), there are actually 22 distinct [symbol]D[/symbol] resonances for which there is experimental evidence.
In practice, a [symbol]D[/symbol] is created in high-energy particle collisions. Once it’s created, it lives for a very short time before decaying into lighter particles. When I say it lives for a short time: with today’s most powerful accelerators, we could make a [symbol]D[/symbol] that goes maybe tens of nanometers before it decays. So, beams of [symbol]D[/symbol]'s aren’t really possible. (They wouldn’t be very useful, actually, so it’s all the same.)
The lightest (and therefore easiest to make) [symbol]D[/symbol] resonance is known as a [symbol]D/symbol (usually read as “delta-twelve-thirty-two”). It’s mass (and there’s some subtlety in talking about the mass of such short-lived particles) is some 30% larger than the proton’s mass. The heaviest probably-observed [symbol]D[/symbol] is the [symbol]D/symbol, with a mass more than three times that of the proton.
If you could bombard something with, say, positively charged [symbol]D[/symbol]'s (which you can’t), then the [symbol]D[/symbol]'s would indeed charge up the target object if you could contain any charged decay products. For example, a [symbol]D[/symbol][sup]-[/sup] might enter your target and stop, but then it would interact or decay, producing perhaps a neutron along with a negatively charge pion ([symbol]p[/symbol][sup]-[/sup]). This pion would subsequently decay into, among other thing, a negatively charged muon ([symbol]m[/symbol][sup]-[/sup]), which might still have enough energy to leave the target, taking with it the negative charge that was originally brought in by the [symbol]D[/symbol][sup]-[/sup]. In the end, then, the original [symbol]D[/symbol] didn’t change the charge of the target.
Graviton searches aren’t really a main focus at Fermilab, although there is always a group of researchers or two looking for indirect evidence as predicted by someone’s pet theory. (It’s unlikely that gravitons can be observed at today’s (or tomorrow’s) accelerators, but it never hurts to look.)
There are many particle physics facilities out there, although most do not overlap much with Fermilab as far as physics strengths. Fermilab currently has three running experiments: CDF and D0 are the two large proton-antiproton collider experiments. Since Fermilab has the highest energy beam right now, these experiments can probe many things better than anyone else. This isn’t true across the board, though, by any means. (For example, experiments at the Stanford Linear Accelerator Center and at Japan’s KEKB facility are the shining stars for any measurement having to do with the B meson.) In general, if someone else can do a particular measurement better than CDF or D0, then CDF and D0 are going to devote efforts elsewhere, thereby optimizing the use of particle physics resources. (These things ain’t cheap.)
The third experiment currently running at Fermilab is MiniBooNE, which is an experiment probing the phenomenon of neutrino oscillations. The field of neutrino physics is quite lively these days, and there are plenty of experiments whose physics goals overlap with MiniBooNE’s. Experiments in France (CHOOZ), England (KARMEN), Canada (SNO), Japan (Super-K, K2K), and more all have impact on MiniBooNE’s physics. A fourth Fermilab experiment, MINOS, is slated to turn on in January, and this experiment will actually have a direct impact on MiniBooNE since the proton source at Fermilab cannot supply both experiments at their full intensities simultaneously.
A few years from now, the Large Hadron Collider (LHC) will turn on at CERN in Switzerland. At that point, Fermilab’s collider program will be bordering on obsolescence.
Yes, although no one ever calls it a psion. It’s refered to as either psi, [symbol]Y[/symbol], or J/[symbol]Y[/symbol]. It consists of a charm quark and a charm antiquark.
Dr. Starfish, I’m not sure how much you know, so let me start by saying there are six “flavors” of quarks, namely up, down, strange, charm, bottom, and top. Bottom and top are also sometimes called beauty and truth. For each quark there is a corresponding anti-quark. Quarks are generally denoted by the first letter of their name, e.g. u for up. Antiquarks are denoted by the letter with a bar over it. By combining these quarks in various ways, it is possible to make many different particles. Two-particle combinations are called mesons, whereas three-particle combinations are called baryons. All particles made from quarks are called hadrons.
(And just in case anyone is confused: S in those tables is strangeness, while the S I used above is spin. Also, on the meson page they used an underline for the antiquarks, rather than the overbar I’m more used to seeing.)
“-on" and " particles” generally mean the same thing. For instance, a “pion” can also be called a “pi meson.” However, for a lot of the particles no one ever says “__-on.” Especially the ones ending in “a.” I’ve never heard anyone say deltaon, sigmaon, etc. (Kaon is OK, but that’s an “ay” sound not an “uh” sound.) Also, if the ___ in “___on” isn’t a greek letter, you probably can’t call it a ___ particle. For instance, no one calls photons “phot particles” or “phot bosons”, and to do so will make you sound rather silly. 
The LIGO started looking for Gravitational waves in the summer of 2004 by using lasers to detect small fluctuations in space. Seems to me that detecting a gravitaional wave would be at least somewhat equivalent to detecting a graviton, but perhaps I’m making a false analogy between gravity waves/gravitons and light waves/photons.
As you suspect, that analogy doesn’t hold up. Gravitational waves don’t need gravitons.
No, the analogy’s fine. The only caveat is that while we’re pretty sure we know what’s going on with electromagnetism on a quantum scale — Quantum Electrodynamics was fleshed out in the '40s and '50s — we don’t have a very good idea how gravity works on a quantum scale. We’re pretty sure that classical gravitational waves exist (their effects have been observed indirectly in the Hulse-Taylor binary pulsar — scroll down to “Measuring Gravitational Radiation”), but it’s conceivable that there’s no analogous notion of a “gravitational particle” in nature. In fact, one of the leading contenders for a quantum theory of gravity, called “Loop Quantum Gravity”, doesn’t include a natural notion of a graviton to the best of my knowledge.
Just to add to this, most of what we do know about gravitons is derived from the properties of gravitational waves. Gravitational waves have no dipole moment but have a quadrupole moment, so if they’re generated by a “particle field” it must be one of spin 2. Gravitational waves travel arbitrarily long distances, so the particle must be massless. Un so weiter.
Thanks for the info…
So if we directly detect gravity waves at LIGO or a similar facility, will there be any tests we can do to see if there is an associated force particle. Again by the same analogy, it seems we could observe whether or not the gravitaional wave is quantized like EM waves are.
Course even if that would work in theory, its probably a lot easier said then done…
We’re almost certain that gravitational waves exist, since they’re well-described in the context of General Relativity, which we seem to understand pretty well. We’re less sure about gravitons, since they would be a feature of a quantum theory of gravity, about which we have only a few inklings. If gravitons do exist in any meaningful sense, then a gravitational wave could be said to be a beam of gravitons. The problem, though, is that we can only detect such beams (or even hope to detect them) if they contain a great many gravitons. The gravitational waves we expect to detect from what we think are typical sources have frequencies somewhere in the vicinity of 1 Hz (that’s the upper end of what the upcoming LISA detector can detect; the currently-operating LIGO has a bit higher-frequency range). That means that a single graviton would have an energy of 1 Hz * hbar, which works out to only 6.6*10[sup]-16[/sup] eV. No particle of any sort has ever been detected at any energy anywhere near that low, even aside from all of the additional difficulties in detecting gravitational phenomena. There are hypothetical sources which might produce gravitons at significant energies (evaporating microscopic black holes almost certainly, and perhaps some sort of Grand Unified Theory particle interactions as well), but I’m not aware of any experimental attempts to detect gravitons from such sources.
More generally, addressing the OP’s question, particles broadly fall into two groups, fermions and bosons. Bosons have a spin which is an integer multiple of hbar (0, 1, 2, etc.), while fermions have a half-integer spin (1/2, 3/2, 5/2, etc.). The Pauli Exclusion Principle prevents fermions from occupying the same state, so fermions can “stack up” to form what’s generally considered matter, while bosons tend to all fall together in a tangled heap, all in the same state, so they don’t form matter.
Among the elementary particles, there are twelve fermions, plus an antiparticle corresponding to each. These are further divided into six leptons, which do not feel the strong nuclear force, and six quarks, which do. The six quarks are, as mentioned, up (charge +2/3), down (charge -1/3), charm (+2/3), strange (-1/3), top (+2/3), and bottom (-1/3). These (and their antiparticles) always combine in ways such that the total charge is an integer, which means you have three quarks, or a quark and an antiquark. The six leptons are the electron (-1), the muon (-1), and the tauon (-1), along with the electron neutrino, the mu neutrino, and the tau neutrino, all of which are neutral. All of the elementary fermions have a spin of 1/2 hbar.
The elementary bosons all appear to be involved in mediating the fundamental forces. The photon has no charge, no mass, a spin of 1, and mediates the electromagnetic force. The photon is its own antiparticle. The weak force is mediated by the W particles and the Z particle, all of which are massive. The W is charged, either +1 or -1, which are antiparticles of each other. The Z is uncharged and is its own antiparticle; it behaves much like a massive photon. These also have a spin of 1. The gluon, which mediates the strong force, also has a spin of 1, and like the photon, it has zero mass and is its own antiparticle. However, it also has a property called color, which quarks also have, and which causes the strong force to behave very differently than does electromagnetism. If the graviton exists, it would also be an elementary boson, with 0 mass and charge and a spin of 2, and it would presumably be its own antiparticle. And finally, a hypothetical particle called the Higgs boson, which is related to the masses of the various particles, would also be an elementary boson, with spin of 0 and no charge.
All other particles known are some combination of these particles, mostly of the quarks. Most of these composite particles are unstable to some degree, and will quickly decay to more lightweight particles.