LHC marches on (Introduction)

by David Turell @, Tuesday, August 14, 2012, 14:27 (4462 days ago)

Studying quark-gluon interactions of early plasma universe:-http://www.sciencedaily.com/releases/2012/08/120813115445.htm

LHC marches on; new startup

by David Turell @, Monday, April 06, 2015, 14:05 (3497 days ago) @ David Turell

Not quite ready to roll. Los of testing and adjusting to do. Will be 40% stronger when fully active:-http://profmattstrassler.com/2015/04/06/the-lhc-restarts-in-a-manner-of-speaking/

LHC marches on; ten years and a lonely Higgs

by David Turell @, Monday, September 17, 2018, 19:11 (2237 days ago) @ David Turell

Ten years and only the Higgs. No supersymmetry found:

https://www.newscientist.com/article/mg23931953-000-the-higgs-hunter-has-just-turned-10...

"Then there is the Higgs boson, of course. Its discovery by the LHC in 2012 represented the crowning glory of the standard model of particle physics, our best stab so far at ordering the bric-a-brac of reality. This was the final confirmation of a theoretical idea conceived five years before Armstrong took his one small step – an inspiring validation of purely intellectual human endeavour.

"It is also where the problems start. “There’s an enormous elephant in the room, and that’s that we know the standard model is not a final theory,” says Tara Shears of the University of Liverpool and the LHCb experiment. It fails to explain the nature of phenomena such as dark matter or dark energy, or even why the measured Higgs mass teeters on the very lowest boundary of what’s possible in a stable universe.

"Supersymmetry was the much-vaunted successor to the standard model, predicting a swarm of additional particles to shore it up. “The LHC has meticulously searched in the open as well as in various nooks and crannies for these and has shown that they are not there,” says Ben Allanach of the University of Cambridge, a former supersymmetry adherent.
That is a blow to theorists’ egos, conditioned by a string of successes culminating in the Higgs discovery. It suggests that, whatever better theory is out there, it will not have the beauty of supersymmetry.

"But no one said probing the essence of reality was easy. The LHC has already determined the contents of the universe with greater precision than any machine before it. Planned upgrades and new analysis techniques will further sharpen its eye. Hints of anomalies already seen may yet lead to insights. If things have gone quiet around the LHC, it is the silence of committed, concentrated endeavour. In Shears’s words, “we have to wait, work hard, and see”.

"We’ll hang on in there – happy birthday, LHC."

Comment: It is unfortunate that the supercollider in Texas was killed when partially built because it was twice the size of the LHC. But the LHC is big enough to show supersymmetry if it existed. Beauty in theoretical equations doesn't prove anything .

LHC marches on; China plans to build a bigger one

by David Turell @, Friday, November 23, 2018, 19:36 (2170 days ago) @ David Turell

Here's the Story:

https://www.nature.com/articles/d41586-018-07492-w?utm_source=briefing-dy&utm_mediu...

"Physicists at Beijing’s Institute of High Energy Physics (IHEP) are are designing the world's biggest particle smasher. If built, the 100-kilometre-circumference facility would dwarf the 27-kilometre Large Hadron Collider (LHC) at CERN, Europe’s particle-physics laboratory near Geneva, Switzerland — and would cost around half the price.

***

"The CEPC will produce Higgs bosons by smashing together electrons and their antimatter counterparts, positrons. Because these are fundamental particles, their collisions are cleaner and easier to decipher than the LHC’s proton–proton collisions, so once the Chinese facility opens, in about 2030, it will allow physicists to study the mysterious particle and its decay in exquisite detail.

"Last week, IHEP published a milestone report outlining the blueprint for the collider. Initial funding for research and development has come from the Chinese government, but the design is the work of an international collaboration of physicists and the team hopes to garner funding from around the world. (Researchers behind a long-planned rival ‘Higgs factory’ known as the International Linear Collider expect to learn by the end of this year whether Japan will stump up the cash to host it.)

"The blueprints reveal that the Chinese collider would run in a circle 100 metres underground, at a location yet to be decided, and host two detectors. At the end of its ten-year lifespan, the electron–positron machine could be upgraded to collide protons at energies seven times those of the LHC at its peak. Ahead of the report’s publication, Nature spoke to Wang about the project.

***

"It has not significantly changed, because international participation is still limited by the financial commitment of the international partners. They are all interested, but they need to get endorsement from their funding agencies. They are waiting to hear the Chinese government’s position on whether to fund it, and that decision depends on the outcome of the R&D. But CERN is working on a new European strategy for particle physics, so we hope that this time the CEPC can be included. A similar process will happen in the United States, probably in the next year or 2020. We hope it will be included in both.

***

"The spallation neutron source in Dongguan is now operating. It is small but good enough. IHEP is also planning a 1.4-kilometre-circumference light source to be built in Huairou, northern Beijing, at a cost of 4.8 billion yuan. This is a circular electron accelerator that can generate synchrotron radiation — X-rays with extremely high intensity. These are useful for almost every research discipline, including materials science, chemistry, biology, environmental science, geology and medicine. We believe the government is going to give its final approval for the project by the beginning of next year, and then we can start construction. We think it would be a world-leading machine. Most light sources are upgrades from existing machines, so they are limited. We can use the best configurations, the best technologies, without constraints."

Comment: this is good news. The LHC is near the end of its limits. I certainly man y not see the new results, but they are needed. We only have a few answers so far.

LHC marches on; ten years and a lonely Higgs

by David Turell @, Saturday, March 30, 2019, 17:59 (2043 days ago) @ David Turell

The LHC has found nothing more of significance beyond the Higgs, and it is too light according to theories. Max Strassler and his group are hunting for new findings in a different approach, but have nothing of significance to report:

https://profmattstrassler.com/2019/03/19/the-importance-and-challenges-of-open-data-at-...

No point in quotes, as they have not found anything important, so on to tehv artic le:

https://aeon.co/essays/has-the-quest-for-top-down-unification-of-physics-stalled?utm_so...

"So when the European Organization for Nuclear Research (CERN) cranked up the LHC just outside Geneva for a second time in 2015, hopes for empirical validation were running high. The fruits of physicists’ most adventurous top-down thinking would finally be put to the test. In its first three-year run, the LHC had already notched up one astounding success: in 2012, CERN announced that the Higgs boson had been found, produced in high-energy, head-on collisions between protons.

***

"This time, though, none of the more exotic particles and interactions that theorists hoped to see has been forthcoming. No ‘stop squarks’, no ‘gluinos’, no ‘neutralinos’. The null results are now encrusting the hull of the Standard Model, like barnacles on a beautiful old frigate, and dragging her down to the ocean floor. It looks like the centuries-long quest for top-down unification has stalled, and particle physics might have a full-blown crisis on its hands.

"This time, though, none of the more exotic particles and interactions that theorists hoped to see has been forthcoming. No ‘stop squarks’, no ‘gluinos’, no ‘neutralinos’. The null results are now encrusting the hull of the Standard Model, like barnacles on a beautiful old frigate, and dragging her down to the ocean floor. It looks like the centuries-long quest for top-down unification has stalled, and particle physics might have a full-blown crisis on its hands.

***

"Instead, many of us have switched from the old top-down style of working to a more humble, bottom-up approach. Instead of trying to drill down to the bedrock by coming up with a grand theory and testing it, now we’re just looking for any hints in the experimental data, and working bit by bit from there. If some measurement disagrees with the Standard Model’s predictions, we add an interacting particle with the right properties to explain it. Then we look at whether it’s consistent with all the other data. Finally, we ask how the particle and its interactions can be observed in the future, and how experiments should sieve the data in order to be able to test it.

"The bottom-up method is much less ambitious than the top-down kind, but it has two advantages: it makes fewer assumptions about theory, and it’s tightly tethered to data. This doesn’t mean we need to give up on the old unification paradigm, it just suggests that we shouldn’t be so arrogant as to think we can unify physics right now, in a single step. It means incrementalism is to be preferred to absolutism – and that we should use empirical data to check and steer us at each instance, rather than making grand claims that come crashing down when they’re finally confronted with experiment.

***

"We began with an experimental signature (the particular bottom meson decays that disagree with Standard Model predictions), then we tried to ‘bung in’ a new hypothesised particle to explain it. Its predictions must be compared with current data to check that the explanation is still viable. Then we started building an additional theoretical structure that predicted the existence of the particle, as well as its interactions. This theory will allow us to make predictions for future measurements of decays, as well as search for the direct production of the new particle at the LHC. Only after any hints from these measurements and searches have been taken into account, and the models tweaked, might we want to embed the model in a larger, more unified theoretical structure. This may drive us progressively on the unification road, rather than attempting to jump to it in one almighty leap.

Comment: Having spent so many years using the standard model, they are trying to squeeze out more info from the collider they have. Most researcher say a more powerful one is needed. But they may be disappointed again. Perhaps a new theory is needed. My quotes have skipped a get deal of theoretical considerations.

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