https://www.quantamagazine.org/crisis-in...-20220301/
EXCERPTS: In The Structure of Scientific Revolutions, the philosopher of science Thomas Kuhn observed that scientists [...] pose and solve puzzles while collectively interpreting all data within a fixed worldview or theoretical framework, which Kuhn called a paradigm. Sooner or later, though, facts crop up that clash with the reigning paradigm. Crisis ensues. The scientists wring their hands, reexamine their assumptions and eventually make a revolutionary shift to a new paradigm, a radically different and truer understanding of nature. Then incremental progress resumes.
For several years, the particle physicists who study nature’s fundamental building blocks have been in a textbook Kuhnian crisis.
The crisis became undeniable in 2016, when, despite a major upgrade, the Large Hadron Collider in Geneva still hadn’t conjured up any of the new elementary particles that theorists had been expecting for decades. The swarm of additional particles would have solved a major puzzle about an already known one, the famed Higgs boson. The hierarchy problem, as the puzzle is called, asks why the Higgs boson is so lightweight — a hundred million billion times less massive than the highest energy scales that exist in nature. The Higgs mass seems unnaturally dialed down relative to these higher energies, as if huge numbers in the underlying equation that determines its value all miraculously cancel out.
The extra particles would have explained the tiny Higgs mass, restoring what physicists call “naturalness” to their equations. But after the LHC became the third and biggest collider to search in vain for them, it seemed that the very logic about what’s natural in nature might be wrong...
[...] At first, the community despaired. ... People wondered more loudly than before whether the universe is simply unnatural, the product of fine-tuned mathematical cancellations. Perhaps there’s a multiverse of universes, all with randomly dialed Higgs masses and other parameters, and we find ourselves here only because our universe’s peculiar properties foster the formation of atoms, stars and planets and therefore life. This “anthropic argument,” though possibly right, is frustratingly untestable.
Many particle physicists migrated to other research areas, “where the puzzle hasn’t gotten as hard as the hierarchy problem,” said Nathaniel Craig, a theoretical physicist at UCSB.
Some of those who remained set to work scrutinizing decades-old assumptions. They started thinking anew about the striking features of nature that seem unnaturally fine-tuned — both the Higgs boson’s small mass, and a seemingly unrelated case, one that concerns the unnaturally low energy of space itself. “The really fundamental problems are problems of naturalness,” Garcia Garcia said.
Their introspection is bearing fruit. Researchers are increasingly zeroing in on what they see as a weakness in the conventional reasoning about naturalness. It rests on a seemingly benign assumption, one that has been baked into scientific outlooks since ancient Greece: Big stuff consists of smaller, more fundamental stuff — an idea known as reductionism. “The reductionist paradigm … is hard-wired into the naturalness problems,” said Nima Arkani-Hamed, a theorist at the Institute for Advanced Study in Princeton, New Jersey.
Now a growing number of particle physicists think naturalness problems and the null results at the Large Hadron Collider might be tied to reductionism’s breakdown. “Could it be that this changes the rules of the game?” Arkani-Hamed said. In a slew of recent papers, researchers have thrown reductionism to the wind. They’re exploring novel ways in which big and small distance scales might conspire, producing values of parameters that look unnaturally fine-tuned from a reductionist perspective.
“Some people call it a crisis. That has a pessimistic vibe associated to it and I don’t feel that way about it,” said Garcia Garcia. “It’s a time where I feel like we are on to something profound.” (MORE - missing details)
EXCERPTS: In The Structure of Scientific Revolutions, the philosopher of science Thomas Kuhn observed that scientists [...] pose and solve puzzles while collectively interpreting all data within a fixed worldview or theoretical framework, which Kuhn called a paradigm. Sooner or later, though, facts crop up that clash with the reigning paradigm. Crisis ensues. The scientists wring their hands, reexamine their assumptions and eventually make a revolutionary shift to a new paradigm, a radically different and truer understanding of nature. Then incremental progress resumes.
For several years, the particle physicists who study nature’s fundamental building blocks have been in a textbook Kuhnian crisis.
The crisis became undeniable in 2016, when, despite a major upgrade, the Large Hadron Collider in Geneva still hadn’t conjured up any of the new elementary particles that theorists had been expecting for decades. The swarm of additional particles would have solved a major puzzle about an already known one, the famed Higgs boson. The hierarchy problem, as the puzzle is called, asks why the Higgs boson is so lightweight — a hundred million billion times less massive than the highest energy scales that exist in nature. The Higgs mass seems unnaturally dialed down relative to these higher energies, as if huge numbers in the underlying equation that determines its value all miraculously cancel out.
The extra particles would have explained the tiny Higgs mass, restoring what physicists call “naturalness” to their equations. But after the LHC became the third and biggest collider to search in vain for them, it seemed that the very logic about what’s natural in nature might be wrong...
[...] At first, the community despaired. ... People wondered more loudly than before whether the universe is simply unnatural, the product of fine-tuned mathematical cancellations. Perhaps there’s a multiverse of universes, all with randomly dialed Higgs masses and other parameters, and we find ourselves here only because our universe’s peculiar properties foster the formation of atoms, stars and planets and therefore life. This “anthropic argument,” though possibly right, is frustratingly untestable.
Many particle physicists migrated to other research areas, “where the puzzle hasn’t gotten as hard as the hierarchy problem,” said Nathaniel Craig, a theoretical physicist at UCSB.
Some of those who remained set to work scrutinizing decades-old assumptions. They started thinking anew about the striking features of nature that seem unnaturally fine-tuned — both the Higgs boson’s small mass, and a seemingly unrelated case, one that concerns the unnaturally low energy of space itself. “The really fundamental problems are problems of naturalness,” Garcia Garcia said.
Their introspection is bearing fruit. Researchers are increasingly zeroing in on what they see as a weakness in the conventional reasoning about naturalness. It rests on a seemingly benign assumption, one that has been baked into scientific outlooks since ancient Greece: Big stuff consists of smaller, more fundamental stuff — an idea known as reductionism. “The reductionist paradigm … is hard-wired into the naturalness problems,” said Nima Arkani-Hamed, a theorist at the Institute for Advanced Study in Princeton, New Jersey.
Now a growing number of particle physicists think naturalness problems and the null results at the Large Hadron Collider might be tied to reductionism’s breakdown. “Could it be that this changes the rules of the game?” Arkani-Hamed said. In a slew of recent papers, researchers have thrown reductionism to the wind. They’re exploring novel ways in which big and small distance scales might conspire, producing values of parameters that look unnaturally fine-tuned from a reductionist perspective.
“Some people call it a crisis. That has a pessimistic vibe associated to it and I don’t feel that way about it,” said Garcia Garcia. “It’s a time where I feel like we are on to something profound.” (MORE - missing details)