Seeking cracks in the Standard Model

January 30, 2015 by Tara Shears, University of Liverpool
Seeking cracks in the Standard Model

In particle physics, it's our business to understand structure. I work on the Large Hadron Collider (LHC) and this machine lets us see and study the smallest structure of all; unimaginably tiny fundamental particles, held together by fundamental forces to provide the microscopic skeleton of matter.

The LHC is shut down at the moment, but will start gearing up for another round of data-taking in about six week's time. Given our success at teasing out the subatomic structure of the universe from the data we've already got, why do we need more? What unfinished business drives us to carry on?

Confirming the Standard Model

If the first data-taking run of the LHC did anything for us, it was to demonstrate how remarkable our theory of the subatomic universe, the Standard Model, is. Our measurements of the particles produced in the LHC, and their subsequent behaviour as they travelled through our experiments, confirmed Standard Model predictions at every stage.

Even better, two LHC experiments found the only particle, the Higgs boson, predicted by the theory and never seen. At Liverpool, we contributed to that discovery and much else besides. When the LHC shut down for maintenance and upgrading in 2013, it did so on a high.

But everything isn't that straightforward.

We may have confirmed our theory again and again but, increasingly, we've also gathered evidence that it isn't right, that it isn't the last word. The Standard Model simply can't explain some of the most prevalent and fundamental features of the universe; the identity of the dark matter that binds galaxies together, why antimatter dropped out of existence less than a second after the Big Bang, even how gravity behaves at the subatomic, scales where quantum rules rule.

We don't even know much about the Higgs boson yet, just that it resembles our expectations, although its true nature might be more exotic.

These observations make us suspect that there must be a better, more fundamental, extensive description of the universe. We just don't know what it is yet. There are hundreds of ideas out there, ranging from gentle extensions of the Standard Model to frankly freaky bizarreness.

One of these, if we're lucky, will be more correct than the theory we have already. We can sift out that theory if we can make just one measurement that supports it, and that disagrees with the Standard Model. That hasn't happened yet. This is why we are keen to test the new data from LHC, where it might, because this is how our understanding of the universe is going to move forward.

This year, LHC steps it up a notch. Over the shutdown it has been so extensively checked out, revamped and optimised, that it is almost a new machine. Over one million man hours have been spent proofing it to operate as close to design energies and beam power as we can get.

The step up in energy from 2012 operation, where the LHC ran at a little over half speed, to 2015, is similar to the step in energy from the world's previous high energy accelerator to LHC when it started. This higher energy unveils the universe in a way never seen before; with more microscopic detail, with a field of view surpassing anything we've ever had.

For us, this is like going to a new world and exploring without a map. We don't know what strange features we'll find, but we're going to look everywhere, and find out. Except our journey is bigger than that; our journey doesn't involve a world, it concerns the universe. This whole enterprise give us such an opportunity and so much potential to find out more. It is a real scientific adventure.

Whatever's out there, we want to find it

Unlike the start of LHC, when we were reasonably sure that we'd either see a Higgs boson or else break the Standard Model if it wasn't there, there isn't a clear path to follow to start our adventure off. There isn't a breach in the theory to prise open to see what lies beneath; we have to find one.

We need to test every part of the Standard Model for cracks with the high energy data, to look for new, unexpected particles that blow our current understanding out of the water, to search everywhere we can with this fantastic machine. Here at Liverpool, we're ready. We have teams working on three of the four LHC experiments, which are poised to interrogate the new data.

Whatever's out there, we want to find it. We have too many unanswered questions about the , and too much unfinished business with it, to stop now.

Explore further: What's next for the Large Hadron Collider?

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16 comments

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movementiseternal
Jan 30, 2015
This comment has been removed by a moderator.
just_think_it
1 / 5 (7) Jan 30, 2015
Spring-And-Loop Theory lacks the drawbacks of the Standard Model.

I have yet to hear a valid criticism of it...

http://www.just-t.../sal.htm
TechnoCreed
5 / 5 (5) Jan 30, 2015
Spring-And-Loop Theory lacks the drawbacks of the Standard Model.

I have yet to hear a valid criticism of it...
You are funny Slinky! You go straight on my ignore list, anyway.
rhugh1066
5 / 5 (1) Jan 30, 2015
I have an honest question, no trolling or pot-stirring intended: what is spacetime? I know Einstein described it mathematically and I know of the bowling balls-on-a-rubber-sheet example of what's it's similar to (which example makes no sense to me, as I assume spacetime fills all of space, not just a flexible surface upon which rides physical objects). I'm asking what is it made of? And please, no cute Unicorn Sweat or Skippy this and that, I'm truly asking what I think is a reasonable question. Anyone? Thanks.
kochevnik
1 / 5 (3) Jan 30, 2015
@rhugh1066 Spacetime doesn't include momentum, by which we infer space and time. So the 'real' space is 8 dimensional phase space with incorporates time, space and momentum. Personally I suspect time is an artifact or a fractal, and so the proper dimension is something like 7.2 which is the dimension in which packed spheres have the least surface area
just_think_it
1 / 5 (3) Jan 30, 2015
My first name is Floyd:
http://www.just-t.../bio.htm
antialias_physorg
5 / 5 (4) Jan 30, 2015
(which example makes no sense to me, as I assume spacetime fills all of space, not just a flexible surface upon which rides physical objects)

You have to look at it as a 2D example of a 4D effect (that doesn't lend itself to drawings on paper very well)

You could wrap your head around a 3D example given a solid rubber volume where some parts are stretched and some parts are compressed (e.g. close to planets), and the geodesics (the lines of travel for photons) are along paths of 'least resistance'...i.e. if you were to shoot first colored lines through that volume (without the stresses placed in) and then place the stresses you'd see a warping of the lines that are nevertheless still the shortest paths (based on the 'least resistance' metric).

What space and time are med OF...well...your guess is as good as anybody's.
gsardin
3 / 5 (4) Feb 01, 2015
Many theoretical physicists are much satisfied with the Standard Model. However, at long run so much complacency is not advisable. What they have really proved in excellence is their expertise in adjusting data. Though, math, which is certainly a key tool in physics, is however a human development (and perhaps of some civilized sympathetic aliens too!). As such, it can serve as well to describe physical reality as to falsify it. Nature does not know about math, it is just due to physical interactions. In its endless chores it makes no calculation, it only interacts, otherwise it would be as clumsy as we are, and most of the time would be wrong or not know what to do, just like us. In our opinion this tendency to equate mathematics with physical reality is a subtle form of animism, but this is another story. Certainly, physical laws do not depend on our math to know how to operate, and when we change them they do not vary accordingly in order to please us.
big_hairy_jimbo
5 / 5 (4) Feb 01, 2015
I really don't know why CERN bother to employ physicists at all, when all they need do is get some of the phys.org posters to show them how it all works. As a collective we have shown time and time again, that we know all. Just ask movementiseternal, he couldn't have said it any clearer if he/she/it tried, ohh and he does EVERY BLOODY DAY, on EVERY BLOODY POST!!!!!

CERN stop wasting your time on theories, experiments, data collection and analysis. Just ask us!!!!!!! Clue it has everything to do with underwater waves and something about expanding and recycling!!!
big_hairy_jimbo
3 / 5 (2) Feb 01, 2015
After careful consideration, I have now concluded that the LHC is really just a Hi-Tech vapouriser for marijuana smoking. They have 4 vape-cambers setup!!!! See they have nearly finished cleaning it all up, getting rid of the residue and re-packing it with several tonnes of dope, ready for the next few years of vapourising. At the end of that lot, no doubt they will have smoked up some new bizarre ideas on how the universe works!!!! Good luck people. Wish I could work with ya!!!
I wonder if they all wear shirts like that guy from ESA Rosetta mission did???
russell_russell
5 / 5 (1) Feb 02, 2015
Stop pouting, Doug.
Mechanics all the way. Think Nambu in your case.
No use in losing faith in the physical.
I Have Questions
not rated yet Feb 03, 2015
I get the impression that I am reading satire.
ekim
not rated yet Feb 03, 2015
I have an honest question, no trolling or pot-stirring intended: what is spacetime? I know Einstein described it mathematically and I know of the bowling balls-on-a-rubber-sheet example of what's it's similar to (which example makes no sense to me, as I assume spacetime fills all of space, not just a flexible surface upon which rides physical objects). I'm asking what is it made of? And please, no cute Unicorn Sweat or Skippy this and that, I'm truly asking what I think is a reasonable question. Anyone? Thanks.

The idea of a holographic universe is an interesting one. Our concept of spacetime is an illusion produced by two-dimensional information structure "painted" on the cosmological horizon. Of course, that just leads to the question, " What is the cosmological horizon made of?"
Losik
Feb 03, 2015
This comment has been removed by a moderator.
gsardin
3 / 5 (2) Feb 07, 2015
The standard model should at least reconsider those fundamentals embedded on the quark and gluons concepts (QCD). It has no horizon of being unitary, moreover it is conceptually quite tangled. Frank Wilczek, Nobel laureate, 2004, said: "from the perspective of QCD, the foundations of nuclear physics appear distinctly unsound". In our opinion, quarks, with their colours, fractional charges, counterfeit masses, and the eight types of gluons, are the equivalent of the epicycles, the deferents, the equant and the circular orbits of the Ptolemaic system. As long as the quark model will remain an enforced mainstream model, ahead standpoints will be inhibited.

Those with some curiosity in pondering a really different view on the nature of elementary particles can give a look at the recent load on researchgate: "Decryption of kaons decay modes", on researchgate.
Osiris1
not rated yet Feb 15, 2015
Quarks are made of Preons! The standard model may have a 'third dimension' of particles and forces; and this may include 'dark matter'! Time may have three dimensions and the only going backward in time not permitted is on an exact congruent reverse three dimensional vector or our present timeline, itself a skew line in temporal coordinates. This would make 'causality' a marginal issue. Who would want to harm anyone's grandfather anyway? And Thomas Wolfe would be happy.

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