Far out cosmology: Where is supersymmetry (Introduction)

by David Turell , Wednesday, September 07, 2016, 05:10 (2998 days ago) @ David Turell

So far the LHC at very high energies has produced no super particles, which had bern expected. Where does that leave us?:-https://www.sciencenews.org/article/supersymmetry%E2%80%99s-absence-lhc-puzzles-physicists?tgt=nr-"For decades, many particle physicists have devoted themselves to the beloved theory, known as supersymmetry. But it's beginning to seem that the zoo of new particles that the theory predicts —the heavier cousins of known particles — may live only in physicists' imaginations. Or if such particles, known as superpartners, do exist, they're not what physicists expected.-"New data from the world's most powerful particle accelerator — the Large Hadron Collider, now operating at higher energies than ever before — show no traces of superpartners. -***-"Whether their pet theories are right or wrong, many theoretical physicists are simply excited that the new LHC data can finally anchor their ideas to reality. “Of course, in the end, nature is going to tell us what's true,” says theoretical physicist Yonit Hochberg -***-"Supersymmetry is not ruled out by the new data, but if the new particles exist, they must be heavier than scientists expected. “Right now, nature is telling us that if supersymmetry is the right theory, then it doesn't look exactly like we thought it would,” Hochberg says.-***-"the LHC, at the European particle physics lab CERN near Geneva, has been smashing protons together at higher energies than ever before: 13 trillion electron volts. Physicists had been eager to see if new particles would pop out at these energies. But the results have agreed overwhelmingly with the standard model, the established theory that describes the known particles and their interactions.-"It's a triumph for the standard model, but a letdown for physicists who hope to expose cracks in that theory. “There is a low-level panic,” says theoretical physicist Matthew Buckley. “We had a long time without data, and during that time many theorists thought up very compelling ideas. And those ideas have turned out to be wrong.” (my bold)-"Physicists know that the standard model must break down somewhere. It doesn't explain why the universe contains more matter than antimatter, and it fails to pinpoint the origins of dark matter and dark energy, which make up 95 percent of the matter and energy in the cosmos.(my bold)-"Even the crowning achievement of the LHC, the discovery of the Higgs boson in 2012 (SN: 7/28/2012, p. 5), hints at the sickness within the standard model. The mass of the Higgs boson, at 125 billion electron volts, is vastly smaller than theory naïvely predicts. That mass, physicists worry, is not “natural” — the factors that contribute to the Higgs mass must be finely tuned to cancel each other out and keep the mass small. (my bold)-"Supersymmetry solves three major problems in physics: It explains why the Higgs is so light; it provides a particle that serves as dark matter; and it implies that the three forces of the standard model (electromagnetism and the weak and strong nuclear forces) unite into one at high energies.-"If a simple version of supersymmetry is correct, the LHC probably should have detected superpartners already. As the LHC rules out such particles at ever-higher masses, retaining the appealing properties of supersymmetry requires increasingly convoluted theoretical contortions, stripping the idea of some of the elegance that first persuaded scientists to embrace it.-***-"The lack of new particles forces theoretical physicists to consider new explanations for the mass of the Higgs. To be consistent with data, those explanations can't create new particles the LHC should already have seen.-"Some physicists — particularly those of the younger generations — are ready to move on to new ideas. “I'm personally not attached to supersymmetry,” says David Kaplan of Johns Hopkins University. Kaplan and colleagues recently proposed the “relaxion” hypothesis, which allows the Higgs mass to change — or relax — as the universe evolves. Under this theory, the Higgs mass gets stuck at a small value, never reaching the high mass otherwise predicted.-***-"One particularly controversial idea is the multiverse hypothesis. There may be innumerable other universes, with different Higgs masses in each. Perhaps humans observe such a light Higgs because a small mass is necessary for heavy elements like carbon to be produced in stars. People might live in a universe with a small Higgs because it's the only type of universe life can exist in. (my bold) -"It's possible that physicists' fears will be realized — the LHC could deliver the Higgs boson and nothing else. Such a result would leave theoretical physicists with few clues to work with. Still, says Hochberg, “if that's the case, we'll still be learning something very deep about nature.'”-Comment: Note my bolded statements. The Standard Model is very consistent as far as it goes. It may not go further. We don't know what we don't know, and what is found in the future may not fit current predictions. This has happened in the past. In this article fine tuning pops out in regard to the small Higgs.