Unveiling the Proton’s Gravitational Secrets: A New Era of Exploration
Mapping the Proton’s Gravitational Influence
In a groundbreaking series of experiments, physicists at the Jefferson Lab are shedding new light on the proton by mapping its gravitational influence. By exploiting the unique ability of photon pairs to mimic gravitons, the hypothesized particles that convey the force of gravity, researchers are indirectly inferring how gravity interacts with the proton. This innovative approach allows them to realize a long-held dream of studying the proton from a gravitational perspective.
“It’s a tour de force,” said Phiala Shanahan, a nuclear and particle physicist at the Massachusetts Institute of Technology. “We don’t know.”
The Energy-Momentum Tensor: A Comprehensive Portrait
At the heart of this research lies the energy-momentum tensor, a matrix of properties that encapsulates everything there is to know about the proton. This tensor, as described in Albert Einstein’s theory of general relativity, dictates how space-time bends around the particle. It encompasses information about the distribution of energy, momentum, and the presence of compression or expansion, all of which contribute to the curvature of space-time.
Unraveling the Proton’s Internal Pressures
In 2018, the Jefferson Lab group published a groundbreaking study in Nature, revealing the astonishing pressures within the proton. At its core, the strong force generates pressures of an unimaginable intensity—100 billion trillion trillion pascals, surpassing even the pressure at the heart of a neutron star. As distance from the center increases, the pressure diminishes and eventually turns inward, ensuring the proton’s stability.
“This comes out of the experiment,” Burkert said. “Yes, a proton is actually stable.”
The Road Ahead: Sharper Gravitational Maps and Digital Experiments
While the current findings represent a significant first step, physicists eagerly anticipate the arrival of the Electron-Ion Collider at Brookhaven National Laboratory in the 2030s. This cutting-edge experiment promises to deliver even sharper gravitational maps of both the proton’s quarks and gluons.
In parallel, researchers like Phiala Shanahan and her team at MIT are pushing the boundaries of digital experiments. By computing the behavior of quarks and gluons using the equations of the strong force, they have estimated pressures, shear forces, and the proton’s radius. Remarkably, their digital findings align closely with the physical results from Jefferson Lab.
Reshaping Our Understanding of the Proton
The gravitationally inspired maps of the proton are already making waves in the scientific community. At CERN, the European organization behind the Large Hadron Collider, physicists have updated their models based on these new insights. The maps suggest that quarks tend to congregate near the center of the proton during certain rare collisions, challenging previous assumptions.
Moreover, these findings may shed light on the enduring mystery of why quarks bind themselves into protons in the first place. The pressure map reveals the strong force’s attraction extending well beyond the proton’s surface, lending support to alternative theories that propose external interactions between wavy, extended quarks as the binding mechanism.
“It’s not a definite answer,” Girod said, “but it points toward the fact that these simple images with elastic bands are not relevant for light quarks.”
As physicists continue to unravel the gravitational secrets of the proton, we stand on the precipice of a new era of exploration. With each experiment and digital simulation, we inch closer to a more comprehensive understanding of this fundamental particle and the forces that govern its existence.
Original story reprinted with permission from Quanta Magazine, an editorially independent publication of the Simons Foundation whose mission is to enhance public understanding of science by covering research developments and trends in mathematics and the physical and life sciences.
5 Comments
Who knew protons had such interesting inner lives? Time to pack for a microscopic adventure.
Diving into a proton? Next thing you know, we’ll be planning vacations to quarks!
Protons: the final frontier of the infinitesimally small, or just a physicist’s daydream?
Venturing into a proton’s core? Talk about an atomic level odyssey!
Exploring the heart of a proton? Sounds like the ultimate tiny frontier quest!