South Dakota Mines assistant professor of physics, David
A. Martinez Caicedo, Ph.D., and his research group are among the scientists who
are part of the recent announcement from Fermi National Accelerator Laboratory
on the MicroBooNE experiment’s first results showing no hint of a sterile neutrino.
MicroBooNE
is a large 170-ton liquid-argon neutrino experiment located on the booster
neutrino beamline at Fermilab. The experiment is a critical part of the
research needed to build and run the massive Deep Underground Neutrino Experiment (DUNE)
now under construction at Sanford Underground research Facility (SURF)
in Lead, SD.
The new results from the MicroBooNE
experiment at the U.S. Department of Energy’s Fermi National Accelerator
Laboratory deals a blow to a theoretical particle known as the sterile
neutrino. For more than two decades, this proposed fourth neutrino has remained
a promising explanation for anomalies seen in earlier physics experiments.
Finding such a particle would be a major discovery and a radical shift in our
understanding of the universe.
However, four complementary
analyses released by the international MicroBooNE collaboration and
presented during a seminar all show the same thing: no sign of the sterile neutrino. Instead, the results align with the Standard Model of Particle Physics,
scientists’ best theory of how the universe works. The data is consistent with
what the Standard Model predicts: three kinds of neutrinos—no more, no less.
Martinez says this research finding is
significant for the neutrino physics community. “The results presented by
MicroBooNE reduced the places where to look for hints of sterile neutrinos,”
says Martinez.
During his post-doctoral work,
Martinez helped build, install and test the system that reduces cosmic-ray
background signals coming into the MicroBooNE detector. He also served a stint
as the experiment coordinator
who made sure the MicroBooNE detector remained operational, “Generally the
collaboration rotated people each six months in this job because you are on
call 24-7 and you’re tasked to make sure everything works,” says Martinez. He and
Ph.D. physics graduate student, Jairo Rodriguez, also built a remote MicroBooNE
operations center on campus that allows graduate students and faculty to
monitor and run the experiment remotely.
Understanding the MicroBooNE detector
technology also helps inform planning for DUNE. Once operational, DUNE will be
among the largest physics experiments on earth. Mines students and faculty are
directly involved in many aspects of DUNE. “Being just an hour away from SURF
and the future site of DUNE is a huge advantage for anyone studying at Mines,”
says Martinez.
Martinez
works
alongside other physicists, including Rodriguez and Arturo Fiorentini, Ph.D., a
former postdoctoral researcher at Mines. The team is working to build
understanding of neutrino interactions inside the liquid argon time projection
chambers used in both MicroBooNE and DUNE. Rodriguez is focusing on developing
software tools that could enhance future searches of proton decay at DUNE. If
proton decay occurs, researchers need to be able to differentiate it from the
interactions between neutrinos and protons inside a liquid argon time
projection chamber. “All of this work being done today in MicroBooNE has a
direct translation to DUNE,” says Martinez.
Experiments like DUNE
not only help solve some of the most fundamental questions of the universe,
they also have huge potential for advancing future technology. “Many of the
technologies developed in experiments like MicroBooNE and DUNE could be applied
across multiple fields. One example of many is the photon detection devices
that are a critical component of these experiments. We work on these detectors
here at Mines, and they may also have important applications in medicine, to
enhance the current technologies to diagnose diseases,” says Martinez.