Homing to ∆G: Study almost negative gluon spin

Researchers have worked for decades to understand architecture in the subatomic world. One of Nottia’s questions is where the proton gets its essential angular momentum, otherwise it is called its spin.

Nuclear physicists speculate that the spin of a proton is likely to come from its components. However, details of Quark and Guron’s contributions remain elusive.

Now, a new study from an international collaboration between physicists summarises the evidence from observations and analysis using lattice quantum chromodynamics (QCD) to see how much the proton spin is from its gluon. It presents a compelling discussion about.

A new paper featuring the results of the study, “New Data-Driven Constraints on the Signs of Gluon Polarization in Protons,” is published in the Journal Physical Review Letters, created by members of the Jefferson Lab Angular Momentum (JAM) collaboration. This collaboration includes theorists, experimenters and computer scientists who investigate the internal structure of subatomic particles via QCD. QCD is a theory that explains how quarks and gluons interact through powerful forces.

The authors, who are members of the Spin PDF Analysis Group at Jam Collaboration, are Wally Melnitchouk and Nobuo Sato of the Thomas Jefferson National Accelerator Facility of the U.S. Department of Energy. Nicholas Hunt Smith, Anthony Thomas, Martin White, Arc Centre for Dark Matter Particle Physics, in the Centre for Subatomic Structures (CSSM) and the Faculty of Physics at the University of Adelaide, Australia. Christopher Cokuza of William Mary’s Faculty of Physics.

Thomas noted that the fruitful connection between Jefferson Lab and the University of Adelaide dates back decades, with physicists working together despite a 14.5 hour gap.

“Many years ago, Wally held a joint position between Adelaide and Jefferson’s labs when Nathan Isger was the chief scientist,” Thomas said. “And I was at Jefferson Lab for six years as a chief scientist from 2004 to 2009. The physics collaboration is underway.”

The group’s latest work addresses knotty questions that must be solved first to advance in understanding the origins of proton spins. What are the signs of ∆G? In other words, is the spin on Gluons negative or positive?

Intrinsic spins of protons

When a physicist discusses a spin of a proton, or any particle, when referring to its inherent angular momentum. The physicists’ concept of subatomic spin is a quantum mechanical idea, so far, explanations from our visible world have been made. It carries the momentum of this corner even when resting. The spin can be negative or positive. Consider clockwise and counterclockwise.

“Spin is a unique feature of the quantum world,” explained Sato. Protons have half a spin. It’s not .51, not .501. That’s not .50001. That’s .5. Each of the components within the proton has its own spin. ”

Melnitchouk said the value of the proton spin has been known since the 1920s. He added that it makes sense that the spin of a proton comes from the cohesive spin of the components that make up the proton.

“What we don’t know is, which part of the spin of a proton is carried by the three valence Quarks of the proton? Which part is carried by the gluon?” he said. “What part of the quark and gluon rotation of the protons, orbital angular momentum, perhaps?

Nailing the signs of ∆G is essential to grasping how protons get spin, and years of observational activity and theory have not provided a definitive answer.

While most physicists thought positive ∆G was more likely, “these negative ∆G solutions are always stuck,” Hunt Smith said. “From a purely physics perspective, there is no reason why we can’t have a negative ∆G.”

New analysis using world first data

Jam Collaborators has been an old and old experience from many experiments, including findings from previous analytical work and programs for Jefferson Lab’s continuous electron beam accelerator facility (CEBAF) and DOE’s Brookhaven’s relativistic heavy ion corridor (RHIC). New observational data have been constructed. National Institute. Both of these particle accelerators are DOE offices of scientific user facilities and are used by nuclear physicists around the world to carry out their research.

“Our analysis was different from the other groups because we really tried to remove theoretical assumptions about how things should behave,” Melnitouk said. I did.

One such assumption was that the unpolarized parton distribution must have a stochastic interpretation. Melnitchouk acknowledged that this assumption about partons (aggregation term for protons, quarks, and other constituent particles within protons) is “technology.”

“But that has been envisaged in previous analysis by other groups around the world,” he added. “And we believe it’s not really basic right now.”

Melnitchouk said that originally Rhic’s observational data created a global consensus heading in the positive ∆G direction.

“But with further analysis things weren’t that clear,” he pointed out.

He said that Jam’s collaborators published their paper a few years ago. The paper was controversial because it defied the common wisdom of the global nuclear physics community of the time.

Meanwhile, HadStruc collaborations addressed the same questions in different ways. They were using supercomputers and lattice QCD formulations to calculate the underlying QCD theory explaining the interaction between proton quarks and gluons.

“You basically discretize spacetime,” explained Hunt Smith. “Cutting space-time into a series of slices makes it possible to calculate many physical properties.”

Subsequent joint jam and hunstruk collaboration analyses led by Joe Carpee, a fellow at the Theory Center for Nathan Isgar, combine the results of the new lattice QCD with experimental data, which still remains negative ΔG while this narrows the room. I noticed that I recognized this.

“There was a slight preference for positive solutions, but it was still not statistically significant,” Hunt Smith said. “This is where our new research begins.”

Energy particles add new data for analysis

He went on to explain how collaborators included data from deep elastic scattering experiments, including those using CEBAF at Jefferson Labs.

“You take an electron and fire it with a proton. The idea is that you can probe inside the proton (the various quarks and gluons inside it), and he said.

Hunt-Smith said the JAM group is particularly focused on High-X data from deep elastic scattering experiments, which is a particularly important result. This data refers to particles detected at particularly high momentum or very high energy, from electron collisions with proton components. He noted that incorporating High-X data requires some additional theoretical considerations.

“So we added that theory,” he said. “We added more parameters to the analysis to explain that additional high-X data, and then played the analysis. And by including high-X data, we could see a statistically significant difference between positive and negative. We found out there is a ∆G replica, an important discovery is that negative things are badly hated.”

Hunt-Smith added that JAM analysis showed that ∆G is constrained not only by High-X data from deep elastic scattering, but also by results from polarized jet experiments from proton impact sets. Research at RHIC and recent HadStruc lattice QCD data.

The results are not entirely inconclusive, but the analysis shows that there are far fewer negative ∆G gluons than ever before.

“I don’t think anyone else has included this Jefferson lab data in this analysis. I think this is a very important feature of this analysis,” Thomas said. “This is a very comprehensive dataset of regions that no one else could reach, and this is the first time it has been included in a comprehensive global analysis.”

Sato said that while jam paper is less likely to cause negative ∆G, it has not completely closed the door to that possibility. He added that additional observational data from instruments such as the Jefferson Lab’s ongoing CEBAF 12 GEV research program and future electron ion corridors could likely replace the remaining theoretical assumptions. Jefferson Lab is a partner at Brookhaven National Laboratory in the design and establishment of electron ion corridors at Brookhaven.

“The door could then be 100% closed,” he said. “But now we’re basically filling that gap.”