It’s been said that a finely tuned ear knows the size and shape of a piano by merely listening to the instrument’s notes. An international team of physicists has now devised an analogous approach to detect the universe’s hidden particles at high energies—opening a potential pathway for discovering new laws of physics.
The work , which will appear in the journal Physical Review Letters , outlines how effective field theory (EFT) coefficients, which quantify how new laws of physics would influence known particle interactions at low energies, can be transformed into information about the nature of these hidden particles. CERN’s Large Hadron Collider, the scientists note, already searches for values of EFT coefficients through its measurement of particle collisions, thereby providing ready-to-use data for this approach.
“Like deducing the shape and mechanism of a piano from the sound of its notes, this breakthrough provides the means to use collider measurements to deduce the details of hidden particles at high energies,” explains Grant Remmen, the James Arthur Postdoctoral Fellow at New York University and one of the paper’s authors.“This solves a classic open problem in particle physics in an elegant and useful way, providing powerful and sharp mathematical tools that bridge high-energy theory and particle physics experiments.”
Detecting hidden particles at high energies is challenging for scientists because these particles stem from collisions at unfathomably tiny distances and then decay quickly, leaving behind only traces of their existence. But finding them is vital in both better understanding the nature of the universe and, relatedly, in potentially discovering new physical laws that the Standard Model of physics—the universe’s “periodic table”—cannot yet account for.
To address this, Remmen, in collaboration with Clifford Cheung, professor of theoretical physics and director of the Leinweber Forum for Theoretical Physics at Caltech, and their colleagues focused on Wilson coefficients, a set of measurable quantities in the EFT that describe the quantum deformations to the known laws of physics—in effect describing how high-energy particles or forces could subtly modify the interactions of known particles. Knowledge of these interactions would alter our understanding of physics beyond the Standard Model. The authors note that while fundamental physics is determined by the particles and fields at the shortest distances, or highest energies, what we can actually measure experimentally often comprises such longer-distance, or lower-energy, effects.
“As with hearing a set of musical notes and using them to decode the shape and mechanism of a piano, the Wilson coefficients are the repackaged, observable information, like the music notes, while the fundamental particles and interactions at high energies are like the structure of the piano that can be inferred from this data,” explains Remmen.
The authors add that this approach overcomes the limitations of experimental research.
“Particle physics experiments do not always operate at high-enough energies or short-enough distances to detect the new particles physicists are hoping to find,” says Remmen. “Instead, sometimes new physics might just give ‘hints’ in the form of tiny deformations of the standard model. The measurements of these tiny effects are difficult to turn into detailed data about new particles that might exist at higher energies.
“This new work fully solves this problem, inventing a new mathematical algorithm for achieving this important translation from experimental observations to new particle predictions.”
Other authors include Francesco Sciotti, a doctoral student at Barcelona’s Institut de Fisica d’Altes Energies, as well as Francesco Calisto and Michele Tarquini, both Caltech doctoral students.
The study "On the Inverse Problem in Effective Field Theory" was funded by the US Department of Energy (DESC0011632), the Walter Burke Institute for Theoretical Physics, the Leinweber Forum for Theoretical Physics, the James Arthur Postdoctoral Fellowship at NYU, and the European Union Next Generation EU.
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Physical Review Letters
Inverse problem in effective field theory