Tag Archives: protons

Physicists Chart the Forces Inside Protons

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Dr. Ross Young at the University of Adelaide and colleagues at the QCDSF collaboration are investigating the structure of the subatomic problem, which seeks to provide further insight into the powers that underpin the natural world. Their results are perhaps the smallest force field map ever produced in nature.

Distribution of the Colour Lorenz forces acting on the unpolarized quarks of the lateral plane (indicated by vector fields) superimposed on the upper Quark density distribution in the impact parameter space of the unpolarized protons. Image credits: Crawford et al. , doi: 10.1103/physrevlett.134.071901.

“We used a powerful computational technique called lattice quantum chromodynamics to map the forces acting within protons,” Dr. Young said.

“This approach allows us to decompose space and time into fine grids and simulate how strong forces (the fundamental interaction that links quarks to protons and neutrons) change in different regions within the proton. I'll do it.”

“Our findings show that even on these tiny scales, the forces involved reach immeasurable, up to 500,000 Newtons, equivalent to about 10 elephants, in spaces much smaller than the nucleus. It has become clear that it is being compressed,” said the University of Adelaide. D. Student Joshua Crawford.

These force maps provide a new way to understand the complex internal dynamics of protons, and why it works in experiments investigating the basic structure of high-energy collisions and materials such as CERN's large hadron criders. It helps to explain.

“Edison didn't invent the light bulb by studying bright candles. He was built on a generation of scientists who studied how light interacts with matter,” Young said. The doctor said.

“Like almost the same, modern research, such as our recent research, behaves how the basic building blocks of matter are struck by light, and at its most basic level of understanding nature at its most basic level. It makes clear that we will deepen the

“As researchers continue to unravel the inner structure of protons, greater insights could help improve the way protons are used in cutting-edge technologies.

“One of the most notable examples is proton therapy, which uses high-energy protons to accurately target tumors while minimizing damage to surrounding tissue.”

“Just as early breakthroughs in understanding light paved the way for modern lasers and imaging, advances in knowledge of proton structures can shape the next generation of applications in science and medicine.”

“By making the invisible forces within protons visible for the first time, this study bridges the gap between theory and experiment, which reveals the secrets of light to change the modern world. It bridges the same way that we did it.”

a paper Explaining the team's results was published in the journal Physical Review Letter.

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Ja Crawford et al. 2025. Lateral force distribution of protons from lattice QCD. Phys. Pastor Rett 134, 071901; doi:10.1103/physrevlett.134.071901

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Physicists conclude the shape factor of a proton’s Grunick gravitational force

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Protons are one of the main building blocks of all visible matter in the universe. Its unique properties include charge, mass, and spin. These properties emerge from the complex dynamics of its basic building blocks, quarks and gluons, explained by the theory of quantum chromodynamics. The charge and spin of protons shared between quarks has been previously studied using electron scattering. One example is the high-precision measurement of the charge radius of protons. In contrast, little is known about the internal mass density of protons, which is dominated by the energy carried by gluons. In a new study, a team of physicists led by Argonne National Laboratory used a small colored dipole to probe the gravitational density of gluons through threshold photogeneration of J/ψ (J/Psi) particles.

Proton valence quarks (blue, red, green), quark and antiquark pairs, and gluons (springs). Scalar gluon activity (pink) extends beyond the charge radius (orange) surrounding the gluon energy core (yellow). Image credit: Argonne National Laboratory.

For many years, nuclear physicists have determined the size of protons by precisely measuring their charge response. This is a result of the proton's charged constituent quarks.

However, determining the size of matter by the size of its protons is a more difficult task. This is because part of the proton's mass is driven by the elusive neutral gluon, rather than by the mass or motion of charged quarks. These gluons combine themselves with quarks within the proton.

The new discovery provides a view of this mass region produced by gluon interactions.

This measurement not only reveals the mass radius resulting from the strong force, but also its confinement effect on quarks that extend far beyond the proton's charge radius.

“A key detail of the proton's structure is its size,” said lead author Dr. Zein Eddin Meziani, a physicist at Argonne National Laboratory, and his colleagues.

“The most commonly used measure of a proton's size is its charge radius, which uses electrons to measure the spherical size of the proton's charge.”

The new measurements come from the J/Ψ -007 experiment at the Thomas Jefferson National Accelerator Facility.

This differs in that a small colored dipole ( ) was used to reveal the sphere size and position of the gluon mass and its range of influence on the gluon within the proton.

In the experiment, physicists used a high-energy beam of electrons to create J/Ψ particles from protons. The J/Ψ particle provides information about the distribution of gluons inside the proton.

Experimenters inserted these measurements into a theoretical model and analyzed them.

As a result, the mass radius of the gluon inside the proton was determined.

Furthermore, the area of ​​influence of a strong force called a confinement scalar cloud, which also affects proton quarks, was also shown.

“This study paves the way for a deeper understanding of the prominent role of gluons in imparting gravitational mass to visible matter,” the authors concluded.

Their paper It was published in the magazine Nature.

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B. Duran other. 2023. Determination of the Grunick gravitational shape factor of protons. Nature 615, 813-816; doi: 10.1038/s41586-023-05730-4

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Physicists’ Discovery Unveils Distribution of Strong Forces Within Protons

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The physics of proton gravitational form factors and their understanding in quantum chromodynamics have advanced significantly over the past two decades through both theory and experiment.a new paper inside modern physics review We provide an overview of this progress, highlighting the physical insights revealed by studies of the gravitational form factor and reviewing its interpretation in terms of the mechanical properties of protons.

A 2D representation of the quark contribution to the force distribution within the proton as a function of distance from the proton center. Light gray shading and long arrows indicate areas of stronger force, while dark gray shading and short arrows indicate areas of weaker force. Left panel: Normal force as a function of distance from center. The arrows change size and always point radially outward. Right panel: tangential force as a function of distance from center. The force changes direction and magnitude as indicated by the direction and length of the arrow. The sign of the force changes around 0.4 fm from the proton center. Image credit: Burkert other., doi: 10.1103/RevModPhys.95.041002.

“This measurement reveals insight into the environment experienced by the proton's components,” said Volker Burkert, principal investigator at the Jefferson Institute.

“A proton is made up of three quarks held together by a strong force.”

“At its peak, this amounts to more than four tons of force that would have to be applied to the quark to pull it out of the proton.”

“Of course, it is not possible in nature to separate just one quark from a proton because quarks have a property called color.”

“Protons have three colors mixed with quarks, and appear colorless from the outside. This is a requirement for them to exist in the universe.”

“When you try to extract a colored quark from a proton, the energy you invested in separating the quarks is used to create a meson, a pair of colorless quark and antiquark, leaving behind a colorless proton (or neutron).”

“In other words, the number four tons represents the strength of the force inherent in protons.”

The result is only the second of the mechanical properties of the protons to be measured.

Mechanical properties of protons include internal pressure (measured in 2018), mass distribution (physical size), angular momentum, and shear stress (shown here).

This result was made possible by predictions from half a century ago and data from 20 years ago.

In the mid-1960s, nuclear physicists realized that if they could observe how gravity interacted with subatomic particles like protons, such experiments could directly reveal the mechanical properties of protons. It was theorized that

“But at the time, we had no choice. For example, if you compare gravity to electromagnetic forces, there's a difference of 39 orders of magnitude. So it's pretty hopeless, right?” said Latifa El-Adhriri, a staff scientist at the Jefferson Institute. .

This data comes from experiments conducted at the Continuous Electron Beam Accelerator Facility (CEBAF) at the Jefferson Research Institute.

A typical CEBAF experiment involves a high-energy electron interacting with another particle by exchanging a packet of energy and a unit of angular momentum called a virtual photon with the particle. The energy of an electron determines which particles it interacts with in this way and how it reacts.

In the experiment, a high-energy beam of electrons interacting with protons inside a target of liquefied hydrogen gas exerted a much greater force on the protons than the four tons needed to pull out the quark/antiquark pair.

“We have developed a program to study deep virtual Compton scattering,” said Dr. El-Adrili.

“This is where electrons exchange virtual photons with protons.”

“And in the final state, the proton stays the same but recoils, and you actually produce one very high-energy photon, and you also get a scattered electron.”

“At the time we acquired the data, we did not know that beyond the intended 3D imaging with these data, we were also collecting the data needed to access the mechanical properties of the protons.”

“It turns out that this particular process, the highly virtual Compton scattering, may be related to how gravity interacts with matter.”

“A general version of this relationship is stated in Einstein's 1973 textbook on general relativity.gravityWritten by Charles W. Meisner, Kip S. Thorne, and John Archibald Wheeler. ”

“In it, they say, “A massless spin 2 field would give rise to a force indistinguishable from gravity, because a massless spin 2 field would couple with a stress-energy tensor in the same way as a gravitational interaction.'' It is written as 'It is from.'.'.

“Thirty years later, theorist Maxim Polyakov continued this idea and established a theoretical foundation linking deep virtual Compton scattering processes and gravitational interactions.”

“This theoretical breakthrough establishes a relationship between measurements of deep virtual Compton scattering and the gravitational shape factor.”

“And we were able to take advantage of that for the first time and bring out the pressure that we gave during the game.” Nature A paper was published in 2018 and now normal and shear forces are being studied,” Dr. Burkert said.

“A more detailed explanation of the relationship between deep virtual Compton scattering processes and gravitational interactions is provided in a new paper describing the first results obtained from this study.”

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V.D. Burkert other. 2023. Colloquium: Gravitational shape factor of protons. Rev.Mod. Physics 95(4):041002; doi: 10.1103/RevModPhys.95.041002

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