由UNH领导的物理学家团队进行的一项新研究大大提高了我们对质子如何, which comprise 95% of the universe, interact with each other. The results, published recently in the journal Nature Physics，为检验自然界四大基本力之一的“强”力提供了一个基准.
“There’s a lot still unanswered about both of those things, the proton and the strong force,” says lead author David Ruth, a Ph.D. candidate at UNH. “This brings us a little bit closer to that understanding. It’s a necessary piece of two very fundamental things in the universe.”
强作用力支配着原子核内部的物质——中子, protons and the quarks and gluons that make them up — bind together. It is the least understood of the four fundamental forces of nature, which include gravity, electromagnetism and the weak force.
“If we really want to understand our world, we have to have a solid theory of that force,” says professor of physics Karl Slifer, Ruth’s advisor and a lead collaborator on the study.
“There’s a lot still unanswered about both ... the proton and the strong force. This brings us a little bit closer to that understanding. It’s a necessary piece of two very fundamental things in the universe.”
The researchers tested two state-of-the-art, 对强作用力的理论计算与在某一状态下探测质子自旋的实验相竞争, or mode of operating, 在哪里组成它们的夸克彼此之间距离很远. 他们的实验结果与其中一个计算结果一致，但与另一个不一致.
“Because these calculation are very complex, each theory group makes different choices about how to do them,” Ruth says about the discrepancy. “由于理论学家在这些计算中做出了一些选择，结果是不同的. If we’re going to understand the strong force, we need to know which one is right, which one is wrong.”
不仅计算极其复杂，而且实验本身也不是在公园里散步. It was conducted a decade ago at the Department of Energy’s Thomas Jefferson National Accelerator Facility; at that time it was the largest ever installation in Jefferson Lab’s Hall A facility.
Neutron Dance
Ruth的研究是最近在知名期刊上发表的第二篇UNH核物理研究. In August 2022, then-Ph.D. student Shujie Li was lead author on an article in Nature that brings new insights to the interaction of nucleons, 在原子的核心形成致密原子核的质子和中子. This study provides a unique observation of quarks, the particles that make up protons and neutrons, 并帮助我们了解中子星的冷致密核物质. 这项工作为其他研究领域提供了信息，包括天体物理学和中微子物理学.
Li, now working at Lawrence Berkeley National Lab, 他与研究生娜塔莉·桑蒂埃斯特班合作完成了这项工作, now an assistant professor of physics at UNH, and the late assistant professor of physics Patricia Solvignon-Slifer. The Department of Energy labeled this experiment “high impact.”
This work was supported in part by the Department of Energy’s Office of Science, Office of Nuclear Physics, and the National Science Foundation.
Read more about the study.
“It took a small army of graduate students, 博士后和技术人员6个月安装，6个月运行,” says Slifer , who led the experiment in 2021, in a Nature Research Briefing that accompanies the article. “Along the way we faced many technical challenges.” Ruth, who will finish his Ph.D. 在接下来的一年里，他分析了实验的数据，但没有出席.
鲁思说，对强作用力的下一步研究将回到理论家的手中. “很多物理学都是理论家和实验家互相扔球. 我们把球扔给理论家，问他们:‘为什么你们的计算不一致? What needs to be done for them to agree?’”
斯利弗可以想象这项工作从理论或实验走向实际应用, 就像一个世纪前我们对核子之间相互作用的理解催生了裂变、聚变和核能等应用一样. “I’m not sure what the applications will be, but that understanding will push new technology in the future,” he says.
In addition to Ruth and Slifer, 这项研究的共同作者是前UNH博士后研究员James Maxwell, now a staff scientist at Jefferson Lab; former graduate students Ryan Zielinski and Toby Badman; assistant professor Elena Long; former postdoc Sara Phillips; and the late assistant professor of physics Patricia Solvignon-Slifer. The work was funded by several Department of Energy grants, including grant DE-FG02-88ER40410 to UNH.
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Written By:
Beth Potier | UNH Marketing | beth.potier@femdomcenter.com | 2-1566
