For decades, scientists have been baffled by protons. Since they are smaller than the wavelength of light, they cannot be seen and thus quantified using traditional techniques. Scientists from all across the world have employed a high-energy neutrino beam to take on this seemingly insignificant problem.
Researchers, including those from the University of Warwick, relied on neutrinos, which are so light they cannot be seen, to study the smallest particles in the universe. At nearly the speed of light, the neutrinos collided with protons (in particular, hydrogen nuclei), releasing energy that could be measured and studied. Since neutrinos are non-conductive and hard to produce in large quantities, this was a significant achievement.
The experiment took advantage of Fermilab’s proton beam, the world’s most powerful source of high-energy neutrinos. Ten years of nonstop data collection from the MINERvA detector near the source. By employing this method, scientists were able to quantify protons (hydrogen nuclei) for the first time, and they gained vital knowledge into neutrino interactions. Tokai to Kamioka (T2K) and other experiments are under underway, and future projects like the Deep Underground Neutrino Experiment (DUNE) will also investigate neutrino properties.
“Manipulating neutrinos is incredibly tough,” stated MINERvA’s Analysis Coordinator, Assistant Professor Xianguo Lu of the University of Warwick. Nevertheless, we were able to use them as a precise instrument to investigate individual protons. Because of the lack of confounding effects from surrounding nuclear matter, measuring neutrino-hydrogen interactions is crucial for future neutrino studies. This study represents the first application of a novel analysis method, paving the way for more precise event-by-event tracking in the future.
Deborah Harris, a professor at York University in Toronto and a physicist at Fermilab, is the other main voice for MINERvA. “When we proposed MINERvA, we never believed we’d be able to obtain measurements from the hydrogen in the detector,” she adds. Great detector performance, novel approaches to data analysis, and a long period of time spent exposed to the world’s strongest high-energy neutrino beam were all necessary to achieve this result.
Understanding data requires a creative and collaborative approach, as shown by the analysis’s findings and the resulting innovative methods. “While many of the components for the analysis already exist, putting them together in the right way really made a difference,” says lead author York University Postdoctoral Researcher Tejin Cai, who did the research for his doctorate at the University of Rochester. “This cannot be done without experts with different technical backgrounds sharing their knowledge to make the experiment a success.”