Lepton Universality In Question, a Standard Model Assumption 62
Charliemopps writes: "Over the past few years, more and more experiments have started to question one of the core assumptions of the standard model: Lepton Universality. Simply put, the weak nuclear force is assumed to work equally on all Leptons (electron, muon and tau). Two years ago The Babar experimental collaboration reported that measurements indicated this may not have been the case. But the measurements were not accurate enough to be definitive.
Now, a report from The LHC shows that they have analyzed their entire dataset of proton-proton collisions and found a rather large discrepancy. These measurements are still not all that accurate. These decays happen so rarely that even with this huge data set there is still about a 1% change they are incorrect. One explanation for such measurements is an as-yet-undiscovered, charged Higgs particle. It would have to be extremely heavy: greater than 109GeV possibly even as high as 150GeV. This is predicted by some models outside of the Standard Model, like Supersymmetry."
Now, a report from The LHC shows that they have analyzed their entire dataset of proton-proton collisions and found a rather large discrepancy. These measurements are still not all that accurate. These decays happen so rarely that even with this huge data set there is still about a 1% change they are incorrect. One explanation for such measurements is an as-yet-undiscovered, charged Higgs particle. It would have to be extremely heavy: greater than 109GeV possibly even as high as 150GeV. This is predicted by some models outside of the Standard Model, like Supersymmetry."
No Problem: (Score:5, Funny)
To "fix" it, just add one or more of the following to the model:
* More turtles
* More nested epicycles
* More dimensions
* Invent dark [something] to plug it
* Say God did it
Profit!
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What happens if I answer "no"?
Re:No Problem: (Score:5, Insightful)
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Gosh science is so expensive. Let's shut it down so we can remain ignorant fucktards forever!
Big Science is expensive (Score:1)
Gosh science is so expensive. Let's shut it down so we can remain ignorant [] forever!
Science in cheap, Big Science is expensive. So, yes, let's shut down some of the expensive Big Science experiments and fund hundreds of other smaller experiments in a range of different fields. No so flashy, but much better value.
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I could not find the 109-150GeV range in the original article, but the Higgs that has been found already has a mass around 126GeV. It seems like an additional Higgs in that range should already have been found by the LHC.
Re:How convenient! (Score:4, Informative)
Consider how long it took to gather enough of the right events to be reasonably certain about the Higgs, the various false alarms that vanished as more data was collected, etc. Another version just a bit rarer could easily be lost in the noise. Or the two could be similar enough that their signals aren't distinguishable from each other yet.
Re:How convenient! (Score:4, Insightful)
Wan't the confirmation just slightly different from what they expected.
The deviation might actually be traces of this unknown 2nd Higgs particle.
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That's correct: there were discrepancies that might-could-possibly have been caused by a Higgs+.
Or by any of a zillion other things, but it was a hypothesis that merited further experimentation.
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A new theory that will require an even more massive supercollider to prove or disprove!
Fine by me. Beats the hell out of another fruitless military adventure in the middle of nowhere or more pork barrel appropriations.
But... (Score:5, Informative)
Except that that LHC's ongoing failure to find any SUSY particles is making it increasingly unlikely Supersymmetry is right either:
http://scienceblogs.com/starts... [scienceblogs.com]
Re:But... (Score:5, Informative)
The data go a long way to ruling out the Minimal Supersymetric Standard Model (MSSM), but other SUSY theories are still in the running. The MSSM has the advantage of being, well, minimal, but there's no special reason to expect the universe to have made it that easy on us.
It's hard to say which theory this points us to, if any, but the Two Higgs Doublet Model (2HDM) is a part of several. Those theories will help refine what kind of data to look for and what kinds of experiments to configure.
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Yes, but as I understand it, the whole point of supersymmetry was to solve the Hierarchy problems. Even if one of those other variants of supersymmetry holds, they would do so at an energy too high to still resolve the hierarchy problem. So the question becomes what the point of them is, other than having supersymmetry purely for the sake of having supersymmetry.
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Let's face it---supersymmetry's entire cachet is based on the minimal supersymmetric standard model. If the minimal model goes away, it will lose so many supporters that it will become yet another one of "those" theories that few (other than its proponents) care about.
Null experiment for the 21st century (Score:4, Interesting)
With regards to Supersymmetry I have the feeling the LHC is going to end up being this century's version of Michelson-Morley.
However, given what happened after Michelson-Morley, we may be in for some very exciting new physics in the years to come if we can disprove Supersymmetry.
(At least I hope we are... :-))
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I think this is what we all hope - that the existing theories may finally be proven wrong. To a scientist, it is always the unsolved problems that are interesting; the journey and the fun is over when you reach your goal.
I'm not sure about Supersymmetry, though - it's only intuition, but my feeling is that it should have been a minimal form of Supersymmetry, if any. Occam's Razor and all that - I believe Einstein once used the expression 'As simple as possible, but no simpler than that'. I think the next bi
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It attempted to detect the relative motion of matter through the stationary luminiferous aether ("aether wind"). The negative results are generally considered to be the first strong evidence against the then prevalent aether theory, and initiated a line of research that eventually led to special relativity, in which the stationary aether concept has no role. The experiment has been referred to as "the moving-off point for the theoretical aspects of the Second Scientific Revolution".
In other words, although the aims of Michelson-Morley were proved wrong, what they did find eventually led to big new science - and the same might apply here once hindsight is brought to bear.
"still about a 1% change" (Score:2, Funny)
Change you can believe in!
"chance", you idiots!!!
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the Standard Model is completely useless for describing the forces that shape and evolve the cosmos: gravitation, dark energy, dark matter. It does not explain neutrino oscillation (neutrino mass). Doesn't give reason for the observed dominance of matter over antimatter. It has a huge number of arbitrary constants not related to each other and no way to predict or give reason for there values.
In short, it's obviously half-assed, a "cooking the books" production
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That's not a very good way to describe it. It's like blaming Boyle's Law for not predicting nuclear fusion. The Standard Model is anything but half-assed. It made a lot of predictions, including previously unseen quarks, mesons, and the Higgs Boson.
Nobody was trying to say that it was the final theory. They know it doesn't incorporate gravity; that's why there's string theory and alternatives (and the challenge of putting together an experiment with sufficient energy to show the discrepancies between genera
Re:The nature of the Standard Model (Score:4, Informative)
The standard model is an extremely comprehensive collection of theories that makes incredibly accurate predictions. It's a crappy computational tool. It's so computationally intractable that it requires supercomputers to simulate even simple multi-particle systems.
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Um, what? Insane pseudoscience at its finest.
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We know this to be true because nothing can be perfectly split
Says what theory? This seems arbitrary and runs contrary to a large amount of particle physics, including some rather basic predictions of things of quantum mechanics and quantum field theory that would be covered in intro level courses on the topic. If the particles leaving an interaction were distinguishable and not "perfectly split," the results of the calculations would be off by a factor of two from measurements because of the way states work out, but they are not.
If a single particle cannot be split into two equal particles, then no two combination of particles can produce the same unique item again.
Even if the previous statement was t
Re:Particles are more unique than thought (Score:5, Insightful)
And that's the problem with applying pop logic to a fuzzy understanding of a vastly simplified description.
Modern quantum theory suggests not only that two examples of the same type of particle are not only completely identical except for certain features like position, but that even talking about particles as if they had individual existence doesn't really make sense.
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Sounds like the simulation we are living in uses some de-duplication in the file system.to save space.
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Actually, you're entirely wrong. Subatomic particles of the same type are fundamentally indistinguishable from each other.
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So, the idea that contrary leptons can be symmetric is absurd.
Not at all. Because, while your considerations are valid in a sense, you fail to take into account the fact that a 'particle' is an abstract entity - a theoretical construct that attempts to sum up a set of measurable characteristics in the data. Whenever we construct a theory, we are looking for things that are looking symmetrical and harmonic in some sense, so the elements in our theory will almost unavoidably be objects with this sort of universal properties.
Of course, being a only model means that any t
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Two hydrogen atoms are completely unique to one another...
That statement is false. Quantum mechanics deals explicitly with "identical particles", which are particles that are literally indistinguishable from each other, but are not the same particle. This is an empirically demonstrable violation of the principle of "identity of indiscernibles", which states that if two things are indiscernible any means whatsoever, even in principle, they are the same thing. Even though we have known this principle to be false for almost a century, philosophers still take it serio
Wrong universality? (Score:4, Funny)
When I grow up I'm going to Lepton University!
No wait...
where are the systematic uncertainties? (Score:1)
1% change they are incorrect (Score:2)
Last gasps of supersymmetry (Score:2)
Honestly.. a 2.6 sigma result? History is littered with 3 sigma results that vanish as more data is taken and detectors and other experimental hardware/software become better understood and modeled.
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Yes, but this isn't the only result. There have been many over the past 10yrs. None are definitive, but they all seem to agree. That's hard to swallow as a random statistical anomaly. Don't get me wrong, it still could be... But it's worth our interest.
august institution (Score:2)