posted
This is a rant to relieve my feelings. Read it only if you're in a mood to sympathise.
Lord, what fools these mortals be! I've been having a discussion with a cretinist over at Fred Williams's board. "Anti-matter does not exist", he assures me blithely, "because it's the opposite of matter : matter exists, and the opposite of existence is non-existence." Or so I believe his argument is, he doesn't seem to articulate it very clearly. I assured him that I work with anti-matter every day, and observe it in a detector. Quoth he : "How can you work with something that doesn't exist?" How, indeed. Argh.
Here's the thread, if anyone wants to laugh themselves sick. Or puke in righteous anger, according to taste.
In order to give this thread a sheen of legitimacy, would anyone care to start a discussion on whether what we observe in detectors is not, in fact, anti-matter, but something with precisely the same properties? Or even just ask some sensible questions about what the properties are?
[ February 06, 2005, 08:40 PM: Message edited by: King of Men ]
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posted
Oops, that's what comes of ranting too fast. I meant, 'a cretinist'. That is to say, someone who believes Genesis is a literal account of the Earth being created 6000 years ago.
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posted
If I understand it, anti-matter is simply matter with the charges of electrons and protons reversed, right?
Linguistics reflects reality, not the other way around. Physicist chose to call it anti-matter, which is damn descriptive within the field. It doesn't mean they think the stuff adopts every connotation possible from the name.
I mean, bottom quarks aren't always on the bottom of a particle.
posted
Beauty quarks, Dag. Beauty. 'Bottom quark' is an American perversion, perpetrated by philistines without an appreciation of the finer points of the English language. Also, what these colonials call 'top' quarks are properly referred to as truth quarks. Alas, my campaign to have 'up' and 'down' renamed 'unity' and 'depth' does not appear to be catching on.
It's not just the charges that are reversed, everything except mass is! That is, electric charge, isospin, weak hypercharge, and colour charge.
And yes, I'm in Cincinnati.
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posted
You're expecting him to take your word on the existence of anti-matter just because you say so? Tilt at any windmills lately?
You might want to try giving him some links that show how antimatter is used by current technology -- like this one.
And the word is creationist. Have at least the common courtesy not to let your disdain actually DRIP from your posts, please.
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I did point out that nuclear weapons wouldn't work if not for the existence of antimatter, but he apparently didn't believe me.
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posted
I was under the impression that you were not in the US. Is it that you grew up in another country, then? Or am I just imagining things?
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posted
Using the same logic, antipasta cannot exist, for it is the opposite of pasta which clearly does exist. Since pasta exists, and the opposite of existence is nonexistence, antipasta does not exist. Q. E. D.
Which is why you should never pay for it, even if your bill includes charges for something that contains the same properties as antipasta. Deny its very existence to the waiter and explain that no one remembers ordering it, or the greek salad.
I have another essay on anticlimaxes, but it's adults-only.
[ February 06, 2005, 11:50 PM: Message edited by: Chris Bridges ]
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posted
So...black is the opposite of white. Black exists. Therefore white does not. The antichrist is the opposite of Christ. If he insists that the antichrist is real, obviously Christ isn't.
Yep, bad logic, that. Some people are stupid, and it's not worth arguing with them.
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posted
I believe the word is antipasto. But I think the Italian "anti-" is the same as the English "ante-". Or I could be pulling this out of my rear. Either way, it clearly doesn't exist.
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posted
I suggest you persuade your opponent to author a thesis on the rationale propping up his argument that anti-matter is non existent. I'll even offer up a title for his tribute to logic. "The Anti Thesis of Logic and It's Bearing on Existence."
Can you explain to me the "right-hand rule" of electromagnetism? Is this just an observed phenomenon, or is there a reason why induced magnetic force rotates in a plane perpendicular to the direction of electrical current flow?
posted
The right hand rule is an arbitrary convention. It could as easily have been the left hand rule, with magnetic field lines being drawn in the opposite direction. The geometry of magnetic field lines (aside from the arbitrary choice of direction) and the behavior of charged particles moving across them is determined by Maxwell's equations, which come out of electrostatics and Special Relativity.
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posted
I'm surprised that Truth and Beauty are still used. Or were you just joshing a complaint about their discontinuance in favor of the less aesthetic Top and Bottom?
And about BaBar and Belle... Was I correct about meaningfully different types of detectors used at the two facilities? ie The detector-types extract different kinds of information which combined provide a more complete data set than either facility would provide individually? Are sufficiently different approaches such that each provides an artifact* check for the other?
That is my impression, but since my readings on b-mesons are recreational rather than professional...
* For those less familiar with the jargon, an artifact is a spurious&unwanted product of the machinery&processing itself rather than a product of the experiment itself (or more accurately, the experiment one thinks one is doing). Using sufficiently different measuring&processing systems provides a mutual confirmation that the other system is working, is being used&interpreted correctly. Kinda like using a map&compass and a GPS(GlobalPositioningSystem)tracker while orienteering. If the different systems aren't in fairly close agreement with each other, ya know ya have problems.
posted
I'm not quite sure as to what you mean by arbitrary, Mike. Do you mean as by definition? ala the direction of current flow means either the travel direction of the electrons or the travel direction of the holes depending on whether one is talking to an electrician or to an IntegratedChip designer.
quote:...behavior of charged particles moving across them is determined by Maxwell's equations, which come out of electrostatics and Special Relativity.
Does the math contain hints about the geometry and nature of gravitational fields as well?
posted
While it's true that we could have gotten a left-hand rule by defining magnetic fields to go in the opposite direction, that doesn't answer the deeper question of why there is a preferred direction at all. Neither the electric force or gravity acts like this - they exert the same force on a particle at rest as on one that is in motion, barring some relativistic adjustments that we can ignore here.
Unfortunately, like many 'why' questions, this is one that physics cannot answer. We have excellent mathematics describing how the electroweak force (for in this context you really do need to consider the electromagnetic and weak-nuclear as one force) acts, but why? Not our field.
Still, there are some things to be said about this. From special relativity, there are five forms a coupling can take : scalar, vector, axial-vector, tensor, and pseudo-tensor. Some of these have a preferred direction, some don't. In principle, any of the forces could be a mix of any of these forms; there's no reason electromagnetism, say, shouldn't be a mix of scalar, vector, and tensor couplings. In that case, it would exhibit one component with no preferred direction and two with different ways of preferring a direction, and we would likely identify them as electic, magnetic, and duppedittic forces. Indeed, it is possible this is the case, and the duppedittic force is so weak we haven't seen it in action yet.
As far as we can tell, though, the electroweak force chose to have vector and axial-vector components in exactly equal proportion; so it exhibits one direction-blind and one directionful component.
On another subject, while it's possible to extract Maxwell from special relativity plus some field theory, historically it was the other way around : Maxwell put together experimental results, and Einstein invented relativity to account for the behaviour of his equations in extreme cases.
As for whether Belle provides a check on Babar : If it didn't, how could we tell? We'd get the same wrong results! We do have a slightly different set of detectors, optimised for slightly different things, but they're not very different. So far the results agree very well except for the puzzling measurement of CP violation in B -> pi pi. No-one is sure what is going on there, and the two experiments differ by atwo or so sigma. Stay tuned!
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posted
Good catch, skillery. I was sufficiently distracted by arbitrary that all I really saw/processed was "blah blah blah Maxwell's equations blah blah blah" in the rest of the post.
Is Mike's posting meant to be one of them thar TechoTroll thingies? A booby trap phrased in just the right manner to mislead, to raise objections with just sufficient vagueness to not be WRONG? ala Maxwell equations >> Helmholtz electromagnetic waves and constant lightspeed >> (Michelson-Morley / Trouton-Noble) kinda >> (Lorentz-Fitzgerald contraction) kinda >> special relativity >> etc etc etc >> reinterpreted Maxwell equations - - - - - - - - - - - - - - - - - - - - - - - - - Edit: the above was written between skillery's and annie's postings, then finally posted before I had seen KofM's new posting.
posted
I didn't intend to be misleading. If I was, then I apologise.
quote:I'm not quite sure as to what you mean by arbitrary, Mike. Do you mean as by definition?
Yes, I meant by definition. I am not a physicist, so I could be wrong here. But I was under the impression that the direction of the magnetic field was chosen arbitrarily. That is, it could have been chosen so that the left hand rule works instead. This wouldn't change the real behavior of charged particles, of course, but it would slightly change how we describe such behavior.
KoM, I'm not sure what you mean by "preferred direction". (Also, I'm not very familiar with the terms you used to describe different types of coupling.) It seems to me, though, that describing magnetism as having a preferred direction is a little misleading. Or at least confusing. Because while a moving charge will experience a force perpendicular to any magnetic field applied to it (and perpendicular to its own motion), the magnetic field itself is perpendicular to the moving charges that gave rise to it. So charged particles, moving or not, exert forces along the axis between them (this is what you mean by axial-vector, yes?). Where is the directionful component?
Sorry if I'm being unclear. OK, I've just found what's bothering me:
quote:While it's true that we could have gotten a left-hand rule by defining magnetic fields to go in the opposite direction, that doesn't answer the deeper question of why there is a preferred direction at all. Neither the electric force or gravity acts like this - they exert the same force on a particle at rest as on one that is in motion, barring some relativistic adjustments that we can ignore here.
Magnetic forces are the relativistic adjustments to electric forces. So really, we're not ignoring them.
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