Comment Re:Primer, the Movie (Score 1) 421
a photon cannot be split [...]
It is true that a free photon can not split into real massive particles. However photons splitting into electron/positron pairs in material interactions are very common.
a photon cannot be split [...]
It is true that a free photon can not split into real massive particles. However photons splitting into electron/positron pairs in material interactions are very common.
Well, you might want to have a look at this:
http://en.wikipedia.org/wiki/File:Carbon_Dioxide_Laser_At_The_Laser_Effects_Test_Facility.jpg
you mean like this:
I am surprised they conclude the fraction of good mails is as high as 5%.
From the CERN mail server report:
Incoming mails: 1992789
Rejected: 1952787 (98%)
Moved to Spam Folder: 14520 (1%)
Good mails: 25482 (1%)
Spam in Total 99%
And this is a good day. Often good mails are less than 1%.
I have no problems editing UTF-8 encoded files with vim.
Only if the distribution is symmmetric.
if you work out what the time dilation effect is at 1.5c [...]
You can't, sqrt(1 - 1.5c/c) is not a real number, that's the whole point.
Btw. the form of this factor in the Lorentz transformations follows from a few very fundamental assumptions. The limiting speed 'c' appearing in the formula on the other hand can not be derived from first principles. So a priori it could be anything. We do know from experiment, however, that this speed is in fact the speed of light.
a) Combining quarks into hadrons in different ways leads to different properties of the resulting bound state. The mass is an obvious example. Unfortunately, while rather easily accessible experimentally, it is hard to predict the mass of bound states with high precision in QCD (the theory describing the strong force). Others properties can be more powerful here. For example the intrinsic angular momentum (spin) and the parity of the bound state. The decay product trajectories from particles with different spin/parity will show different angular distributions. By measuring these distributions one can rule out certain combinations.
b) In general what would be required is someone working out in more detail how these predicted particles would interact with known particles, in this case charm and strange quarks. I just read through the article you linked to. According to the article, all predicted particles are gauge bosons, i.e. they introduce new interactions. The number in the name Y(4140) refers to the mass measured in MeV. A gauge boson with such a low mass coupling to quarks would have been noticed already. Furthermore, the reported observation does not hint anything exotic. Just something that is perfectly allowed in the Standard Model, although not fully understood in its dynamics yet. So I'm afraid, no, this is not a candidate for your favourite model.
Right. One can also create an undefined reference without explicitly de-referencing a NULL pointer:
FOO& bar()
{
FOO f;
return f;
}
Any decent compiler will issue a warning, though.
Happiness is twin floppies.