For Philip Rodrigues, a postdoc at the University of Rochester, receiving a new dataset from the MINERvA neutrino experiment means two things: that one of the neutrino experiments in which he participates has met a milestone and that the other can verify some of its predictions.
Rodrigues, who is a member of both MINERvA in the US and the T2K experiment in Japan, is not the only neutrino physicist to double dip like this. More than 50 percent of neutrino researchers work on multiple projects simultaneously.
“You want the scientists designing future generations of experiments to have a broad experience in current neutrino research,” says Fermilab physicist Debbie Harris, co-leader of the MINERvA neutrino experiment. “So it’s great to have people on multiple projects.”
Unlike collaborative neutrino researchers like Rodrigues, the neutrino is extremely anti-social. We can’t see it, we can’t feel it, and we don’t entirely understand it. But it may be important for understanding the formation of the universe.
The elusive nature of neutrinos makes working together even more appealing. Scientists who share Fermilab’s neutrino beamline meet regularly to discuss neutrino flux, the quantity of neutrinos per unit area observed in the detectors, and how that information can inform their respective projects.
“It’s impossible to have one detector that can measure every little last thing about the interaction at every neutrino energy that’s important,” Harris said. “So that’s why we need to have a lot of different experiments to help each other make these measurements.”
Neutrino experiments are usually in one of two categories: interaction experiments and oscillation experiments. The primary goal of interaction experiments is to observe the way neutrinos interact with different materials. The primary goal of oscillation experiments is to observe the way neutrinos, which come in three types, change from one type to the next. Both types of experiments can give researchers insight into neutrino characteristics such as their masses and how the different types of neutrinos relate to each other.
Both kinds of experiments shoot extremely intense beams of neutrinos at particle detectors, but the placement of the detector depends on the type of experiment. Detectors for oscillation experiments are located much farther away, miles from the neutrino source, to give the particles time to change.
Data from interaction experiments is critical for scientists at oscillation experiments to understand how the particles will interact in their detectors.
“Neutrinos are neutrinos, and we can measure how they interact with different nuclei, and those results can help us constrain models,” Harris says. “Then those models can be used for experiments that use the same type of target for their far detector.”
In addition, data from similar experiments can be used to double-check one another.
“I think the more data we can get, and the more measurements we can take, the more input we have to help us understand what’s going on in terms of the physics,” Rodrigues says. “It’s very useful, both for the individual experiment, as well as the advancement of the field as a whole.”
