Recent content by Parlyne

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    How do protons decay?

    The basic process I describe for two protons can easily enough be modified to cover the other possibilities. Basically, you can replace any proton in that process with a neutron as long as one of the positrons changes into an anti-neutrino; and, you can also replace every particle with its...
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    How do protons decay?

    I assume you're asking about B-violating decays specifically, as there are many B-conserving nuclear decays that are well-known. Generically, sphalerons should be applicable to any process where B changes by 3 and B-L is conserved, provided that the process correctly conserves electric charge...
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    How do protons decay?

    So far as I know, sphalerons are the only source of B-violation in the Standard Model.
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    How do protons decay?

    Whoa, didn't think I'd see this thread resurrected... Anyway, I didn't say that the chiral anomaly violates B, I said that the V+L violation from sphalerons is like what happens with the chiral anomaly in that it's an effect that isn't explicit in the model but, rather, comes about due to some...
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    Photon absorption

    I'm going to have to disagree with Bill_K. This should, in fact, be possible; but, it should also be such a highly suppressed process that, in practice, we should never have significant enough statistics to have a reasonable chance of seeing it happen. The problem is that changing flavors...
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    Photon absorption

    It's actually pretty simple. In addition to conservation of energy and momentum, each particle must satisfy m^2 = E^2-|\vec{p}|^2. (Note that I'm using natural units where c=1. If you want to use conventional units, multiply every m by c2 and every p by c.) For the photon, which has m_\gamma...
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    Electron change?

    Or, we could just admit that Newton's original formulation was maybe not the best way to express the dynamical idea in the first place. Even in classical physics we can find places where F = ma doesn't work. But, \vec{F} = \frac{d\vec{p}}{dt} will; and, it will continue to work even in SR...
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    Electron change?

    So basically, the article is saying that relativistic mass is useful for hiding the places where relativistic dynamics are actually different from what would be expected classically. Again, though, most of those cases come right back to insisting that momentum is mv. And, the invoking of GR is...
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    Electron change?

    It doesn't. Energy increases without bound as speed approaches c. In the early days of relativity, some physicists found it convenient to define a quantity called "relativistic mass", which is really just energy divided by c2, because its use made the relativistic formula for momentum look...
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    Speed of light and dark matter

    Not at all. I'm just saying that the reporting of this result as evidence for dark matter is not a responsible representation of the data. I happen to think the AMS is an awesome experiment; and, I was actually quite excited when the shuttle mission was added in order to deliver it...
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    Speed of light and dark matter

    Despite the significant hype, the AMS results in no way point to dark matter any more than previous data about the same phenomenon had. The positron excess under discussion was actually first noted about 5 years ago by the PAMELA experiment; and, there was a flurry of papers at the time...
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    Speed of light and dark matter

    Your mistake seems to be in the presumption that all transverse waves must be mechanical. But, there's no reason for such a presumption. As DaleSpam points out, transverseness implies polarizability; and, I'll just add that the dynamics of the electromagnetic field require that, in the absence...
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    Speed of light and dark matter

    What makes you think that causality is fundamental in the first place? More to the point, though, all I've been trying to point out throughout this discussion is that causality is a separate issue from the validity of SR, as SR is simply about Poincare invariance. I personally suspect that...
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    Speed of light and dark matter

    Who said anything about violating Lorentz invariance? The simple statement I gave not only entails Lorentz invariance, it also requires translation and time translation invariance, giving the actual symmetry group of SR - Poincare invariance. Tachyons do not violate this. They only violate...
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    Neil Armstrong and unfaithful wives

    This appears to be the same as the blue forehead room puzzle; and, the answer has been discussed in some depth there. Suffice it to say .
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