Monday, May 31, 2010

Neutrinos have mass!

Scientists the INFN1’s Gran Sasso laboratory in Italy announced today that they have detected a muon neutrino spontaneously changing into a tau neutrino . This is exciting because the standard model of particle physics says that neutrinos don't have any mass, but in order to undergo this spontaneous change they must have a non-zero mass. So this means new physics could be at hand. It also means that neutrinos are a candidate explanation for dark matter.

From a philosophical point of view two things are worth noting. First, obtaining this result took years of painstaking work. And second, despite the fact that this result contradicts the orthodox view, it is being received with open arms, even excitement, but the scientific community. Contrary to the claims of creationists, scientists love it when experiments show that a theory is wrong because that is the only way that scientific progress is made. But nowadays, results of this magnitude are very hard to come by and they just don't happen very often.


[UPDATE:] Rob Warnock sent me an email that basically says that I have this all wrong. Rather than try to distill his critique at the risk of getting it wrong again, I'll just post what he sent me, edited for formatting only:


While this is indeed very interesting news, your article puts all the
emphasis on neutrinos having mass. But what was actuallyu announced by
CERN is simply that a muon neutrino was "caught in the act" of changing
into a tau neutrino, *not* that neutrinos change (oscillate) between
flavors nor that they have mass (which oscillation *requires*) -- that's
rather old news from the 1990s [with roots back to the 1950s]:
Neutrinos have a very small, but nonzero mass.
The solar neutrino number discrepancy problem
Starting in the late 1960s, several experiments found that the number
of electron neutrinos arriving from the Sun was between one third and
one half the number predicted by the Standard Solar Model (SSM). This
discrepancy, which became known as the solar neutrino problem, remained
unresolved for some thirty years. The Standard Model of particle
physics (SM) assumes that neutrinos are massless and cannot change
flavor. However, if neutrinos had mass, they could change flavor
(or oscillate between flavours).
Direct detection of flavor oscillation in solar neutrinos
Starting in 1998, experiments began to show that solar and atmospheric
neutrinos change flavors (see Super-Kamiokande and Sudbury Neutrino
Observatory). This resolved the solar neutrino problem: the electron
neutrinos produced in the Sun had partly changed into other flavors
which the experiments could not detect.
The Standard Model of particle physics assumed that neutrinos are
massless, although adding massive neutrinos to the basic framework is
not difficult. Indeed, the experimentally established phenomenon of
neutrino oscillation requires neutrinos to have nonzero masses.[11]
This was originally conceived by Bruno Pontecorvo in the 1950s.
In 1998, research results at the Super-Kamiokande neutrino detector
determined that neutrinos do indeed flavor oscillate, and therefore
have mass. While this shows that neutrinos have mass, the absolute
neutrino mass scale is still not known.
The initial results indicate |#m232| = 0.0027 eV^2, consistent with
previous results from Super-Kamiokande.[22] Since |#m232| is the
difference of two squared masses, at least one of them has to have a
value which is at least the square root of this value. Thus, there
exists at least one neutrino mass eigenstate with a mass of at least
0.04 eV.[23]

In 2009 lensing data of a galaxy cluster were analyzed to predict a
neutrino mass of about 1.5 eV.[24]

I don't know if it's hard to change articles once they're on Blogspot,
but you might want to shift the focus just a little bit, to put the
emphasis on the observation of the very specific flavor changing that
they saw. Muon neutrino <--> electron neutrino oscillation had been seen
[or at least inferred] before [in the context of the Solar "missing" neutrino
problem, as above], but direct observation of muon neutrino <--> tau neutrino
had never been seen before... which is the news here.

You might also be interested in comparing the coverage of this on
Tommaso Dorigo's excellent blog, which also has some background
on the history:
OPERA Sees Tau Neutrino Appearance!!
By Tommaso Dorigo | May 31st 2010 03:17 PM
In the late 1990s the Super-Kamiokande experiment in Japan proved that
neutrinos may "oscillate": they may change flavour, such that a muon
neutrino may turn into an electron neutrino, or vice-versa. But a muon
neutrino had never been directly seen turning into a tau neutrino yet.

Best Fan Fiction Ever

I wasn't planning on blogging about this until later, but since Miles pointed out that I'm being pretty gloomy lately I decided to go ahead and mention this now. Eliezer Ydkowsky has written what is quite possibly the best work of fan fiction ever written. Well worth the read, and that's saying something because it will take you a few hours to get through it all. If you haven't read any of the original Harry Potter books (or seen the movies) do that first or it won't make a lot of sense.

I'm starting to think that Eliezer is actually as smart as he thinks he is. That would be really scary.

I would have given long odds against

It appears that there may be some actual benefits from acupuncture.

And we wonder why they hate us

As usual Glenn Greenwald gets to the heart of the matter:

Late last night, Israel attacked a flotilla of ships in international waters carrying food, medicine and other aid to Gaza, killing at least 10 civilians on board and injuring at least 30 more"...
If Israel's goal were to provoke as much disgust and contempt for it as possible, it's hard to imagine how it could be doing a better job.
it is only American protection of Israel that permits the Israelis to engage in conduct like this. ... it is only the massive amounts of U.S. financial and military aid, and endless diplomatic protection, that enables Israel to act with impunity as a rogue and inhumane state.

There's more, of course. Worth reading the whole thing.

[UPDATE] I wrote in a comment that boarding a ship without permission in international waters is piracy. Turns out it's only piracy when it's done by a non-government entity. If a government does it (as in this case) it's an illegal act of war. Israel can't have it both ways. Either it is occupying Gaza or it is not. If it is, then it has a responsibility to look after the welfare of its inhabitants, and if it isn't then it has no right to blockade Gaza's ports. One way or another, Israel is clearly on the wrong side of the law.

Sunday, May 23, 2010

My sentiments exactly

Heather Havrilesky asks How can the Lost finale not suck?

[UPDATE:] Yep, pretty much every bit as bad as I was expecting it to be. God, I'm glad that's finally over. When Lapidus sends Miles out to repair a hydraulic leak on a jet airplane with duct tape I actually laughed out loud. That was pretty much the highlight of the show for me.

What a waste of talent and potential.

[UPDATE 2:] It was almost worth putting up with the last few years of Lost just so I could fully appreciate Jack Shafer's brilliant shredding of the finale. Laura Miller's deconstruction over at Salon is pretty good too. More cathartic than the actual finale.

Tuesday, May 18, 2010

Another step towards totalitarianism

A Pennsylvania man faces eight years in prison on what are almost certainly trumped up charges of assaulting a federal agent. The alleged "assault" was almost certainly (the crucial evidence is being held by the government) nothing more than an attempt to photograph the agents on public property, which is not and never has been a crime. But it may soon become one if people continue to sit idly by.

The right to be wrong

Slate has a fascinating interview with Diane Ravitch, former member of the Bush I administration, about her changing her position on the value of public education. But education is just the MacGuffin, the piece is really about being wrong, and being able to admit it. This is my favorite part:

"I sometimes wonder whether you might be attracted to the things that you say are wrong—if you're kind of guarding yourself against something that secretly appeals to you. It's like people who are vehement, militant atheists; I think they could easily become religious crusaders, because they're almost religious in their atheism. You have to be careful what you choose to engage yourself with, because the thing you're fighting could be the very thing you want."

But it's worth reading the whole thing.

Tuesday, May 04, 2010

Facebook goes towards the dark side

Facebook seems to be getting more and more evil. I have an FB account. I hardly ever use it, but I'm seriously considering shutting it down regardless. Assuming I can figure out how.

Saturday, May 01, 2010

More CSS vindication

Finding examples of things that CSS can't do seems suddenly to be all the rage.

Here is my favorite example of something that is impossible in CSS but trivial with tables: a fluid layout with nested grids, such as what you need if you want to lay out a form inside a multi-column page.