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Comment Re:I'm dumb, I think. (Score 2, Informative) 194

There's a few things going on here that are related in different ways.

1) The single-top isn't the only quark being produced, it's actually produced with a bottom quark at the same time. Usual top quark production is in pairs, one top quark one anti-top quark, but single-top is different; a top quark is produced with a anti-bottom quark.
2) The top quark decays before it can hadronize. That is, it decays before it can pick up a partner quark. This is completely allowed in the Standard Model, but I'm a bit sketchy on the details. I think it behaves as though it was attached with the other quark it was produced with.

Comment Re:Explanation wanted (Score 4, Informative) 194

The fine article says that this results limits the number of possible quarks. Can someone give an explanation (or even the outline of one) at a level that someone with a B.S. in physics can understand?

One of the things single-top is sensitive to is the coupling strength of the top and bottom quarks via the weak force. The value of this coupling is tightly constrained if one assumes that there are only six quarks (ie. there are three generations of matter). The fact that they measured it and it's within the six quark ballpark means that it is very likely that there isn't another pair of quarks waiting to be discovered.

The basic idea is that if the top and bottom coupling strength is measured to be less than the value we expect for six quarks then that means that some of that coupling strength actually goes to a different, seventh or eighth, quark. But I'm grossly simplifying things here for the general slashdot crowd.

Comment Re:Bare/Single quark? (Score 4, Interesting) 194

This is not a major discovery, but it is another important showing off of the 'standard model' working very well at the energies we have so far probed.

Single-top is, however, one of the backgrounds in the search for the Higgs boson. For Fermilab to discover the Higgs, they have to discover single-top first.

Comment Re:it's a faked signal (Score 4, Informative) 194

Emphases mine... I am not convinced this isn't a faked signal. With that possibility having a chance of one in four million, how many millions of collisions have they done in the past 15 years? Far more than 4 million, I would suspect.

You aren't quite grasping what he means by one in four million. This wasn't a single event we are talking about here.

The way the statistics work is that you would have to run the entire Fermilab experiment four million times to get what they see from a fake signal. It's a cumulative probability over all the events ever recorded at Fermilab.

...and another thing. Look at that diagram showing a muon went here and a neutrino went there - how in the world did they detect that neutrino, I ask? I bet it zipped right through their detector without so much a pausing to say hello.

They didn't detect it directly. The key to 'detecting' the neutrino is to count up everything else in the remnants collision and notice that it recoils off of something that you didn't detect. It acts as though what you can see in your detector is violating the conservation of energy. But in reality there's an undetectable neutrino zipping through the detector. So you calculate how much energy and in which direction such a neutrino would travel in order to conserve energy, and that's where they get that little diagram.

Comment Re:Too many loopholes (Score 1) 230

Arbitary codes like this and One time pads have been proven (when done correctly) to be absolutely secure, whereas all encryption in theory is insecure (the only exception is quantum encryption)

The thing is, quantum encryption is a one time pad system. It's a secure way of distributing the one time pad.

Wireless Networking

Submission + - 700MHz spectrum auction wraps up (arstechnica.com)

Analog boy writes: The FCC's 700MHz spectrum auction has finally come to a close. The final tally on bidding was $19.592 billion. The open access Block C topped $4.8 billion, but Block D will likely be reauctioned after only getting a single bid. 'Block D never saw any action after an initial $472 million bid. That chunk of spectrum was supposed to be used for both a commercial broadband service and a nationwide emergency communications network. Frontline Wireless was expected to be a major player for Block D, but it dropped out before the auction began. With the Block D reserve unmet, the FCC has the option of auctioning it off again with different rules or a lower reserve.' The FCC is expected to reveal the identities of the winning bidders soon.
Government

Submission + - White House tape recycling possibly erased emails (washingtonpost.com) 1

Pojut writes: "The Washington Post has a story up that the White House has acknowledged via a court filing that they recycled backup media containing emails up until October of 2003. From the article:

"The disclosure raises the possibility that the White House effectively erased e-mail related to some of the biggest controversies of the Bush administration, including the leak of a CIA officer's name, the start of the Iraq war and the CIA's destruction of interrogation videotapes."

$20,000 for a toilet seat isn't too expensive, but $1000 for some more backup media is?"

Government

Submission + - Effects of new German copyright law on science

Kleiba writes: On January 1st, the controversial reforms of German copyright law became effective. While the effects on the right to create copies for personal use have been discussed passionately in public, little attention has been payed to other fields affected by the changes, such as science. I am a scientist working at a research institute in Germany and I enjoy the fact that the web made access to colleagues' publications very easy: most of the time you can find a PDF on a researcher's homepage. Likewise I provide download links to my own papers. But now my institute points out that since the beginning of the year, it's not only illegal to make papers available for download of which you don't own the copyright (think reading assignments in seminars and university classes), but also even to download publications from sources other than the copyright holder. In practice, I assume this will be almost impossible to assess. Still, I will probably remove links to papers on my homepage myself: it's just too complicated and time consuming to think about who holds the copyright on each single publication (me? one of the co-authers? the journal? all of us?). Now, I was wondering what slashdotters think about what effects legal changes like these will have on the progress of science in Germany and in general.
Privacy

Submission + - UK to imprison for inability to decrypt data

mrbluze writes: Ars technica has an article describing new laws which come into effect on 1st November in the UK. Up to 2 and 5 years imprisonment can be inflicted on any person who refuses or cannot provide keys or decrypt data as requested by police or military for criminal or anti-terror purposes, respectively. From the article:

The Home Office has steadfastly proclaimed that the law is aimed at catching terrorists, pedophiles, and hardened criminals — all parties which the UK government contends are rather adept at using encryption to cover up their activities.
It refers to a potential problem faced by international bankers who would be wary to bring their encryption keys into the UK. Some how I doubt that is the real problem with the law.
Announcements

Submission + - New Record Superconductor Discovered

Dean Edmonds writes: "Superconductors.org is reporting a new record for high-temperature superconductivity. The new material shows both resistive and Meissner transitions around 175K (-98C), 25 degrees higher than the previous record holder. To put that in perspective, the coldest temperature ever recorded on Earth was 184K (-89C) at Vostok Station, so we're getting close to 'room temperature' superconductors, just so long as the room is in Antarctica."

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