Wednesday, June 9, 2010

Let's get physical

From the world of experimental physics, two very interesting recent reports ...

Theory suggests that the Big Bang should have created matter and antimatter in equal quantities. But of course related matter and antimatter particles (e.g., proton and antiproton), when they meet, create a big bang all their own. After a while, if all were in balance, one would expect matter and  antimatter to wipe each other out.

So: how are we made-of-matter beings here to wonder about such things?

Theoreticians still can't say, but here's some new data for them to chew on. Researchers at Fermilab have been smashing protons and anti-protons together at high velocities/energies and observing the debris. In that debris, to their great surprise, they saw more muons than antimuons.

Way to go, matter! Details here.

Now on to the elusive neutrino (Italian for "little neutral one"). Neutrinos shoot through the entire Earth like it's not even there.  (The sun spits out neutrinos by the gazillions, as part of the fusion process.)

Neutrinos are necessary to balance equations in nuclear physics (e.g., to maintain conservation of momentum in certain particle collisions and decays); neutrinos were surmised to exist long before they were detected. Not that anyone has ever seen one:  physicists back into their confirmation of the existence of neutrinos from the behavior of debris when, rarely, a neutrino does react with another particle.)

Because neutrinos interact very weakly with regular "stuff," researchers must look long and hard to catch even one in the act of ... well, anything.  Fortunately, experimental physicists can be very persistent. They recently spotted a couple of neutrinos in the act of changing into a different type of neutrinos. (Not with very high statistical significance, so this finding requires confirmation, but still fascinating.) If confirmed, the upshot will be that neutrinos have mass.

And if neutrinos have mass, that (a) pokes a hole in the Standard Model of nuclear physics that has been evolving over the past forty-plus years and (b) makes the neutrino a strong candidate for the nature of dark matter.

As a (once upon a time) physicist, I'm excited. As an SF writer, I'm really excited.

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