Prof. Dr. Dmitry Budker, Dr. Konstantin Gaul, and Dr. Lei Cong
Photo Credit: Courtesy of Johannes Gutenberg-Universität Mainz
Scientific Frontline: Extended "At a Glance" Summary: Molecules Probing Dark Matter
The Core Concept: Researchers are utilizing precision measurements of barium monofluoride (BaF) molecules to explore unmapped interactions between electrons and atomic nuclei, yielding new constraints on particles that may constitute dark matter.
Key Distinction/Mechanism: Instead of relying solely on massive particle colliders or cosmological data, this methodology investigates a previously unexplored regime of fundamental forces by tracking potential atomic-level interactions mediated by hypothetical Z' bosons.
Major Frameworks/Components:
- Barium monofluoride (BaF) molecules utilized for precision laboratory measurements.
- Z' bosons acting as hypothetical mediators of weak interactions.
- Extensions to the Standard Model (SM) of particle physics.
- Electron-nucleon interaction constraints.
Branch of Science: Particle Physics, Molecular Physics, Astrophysics.
Future Application: Enhancing the sensitivity of laboratory-scale molecular experiments to detect theoretical, non-Standard Model particles, offering a terrestrial alternative to high-energy astrophysical observations.
Why It Matters: Dark matter comprises approximately 23 percent of the universe, yet its exact particulate nature remains completely unknown. This specific research addresses a critical blind spot in physics by mapping uncharted fundamental forces between ordinary matter.
Analysis of Precision Measurements of Unexplored Interactions Between Electrons and Atomic Nuclei Yields Information on New Particles
Dark matter particles could mediate the interaction between electrons and atomic nuclei, according to a study conducted by junior group leader Dr. Konstantin Gaul, Dr. Lei Cong, and Professor Dr. Dmitry Budker of Johannes Gutenberg University Mainz (JGU), the Helmholtz Institute Mainz (HIM), and the PRISMA++ Cluster of Excellence. Their work, published last week in the renowned journal Physical Review Letters, presents new constraints on previously unexplored candidates for dark matter and, more generally, some hypothetical particles that are not included in the Standard Model of particle physics (SM).
Using results from precision measurements of barium monofluoride (BaF) molecules, the team constrained these interactions, which are mediated by Z′ bosons, for the first time. Z′ bosons are hypothetical mediators of the weak interaction and possible dark matter particles in several SM extensions. “These results address a significant blind spot in physics: a regime of forces between electrons and nuclei that had remained unexplored by both laboratory experiments and cosmological data,” Gaul explained. The universe is composed of approximately 4 percent visible, or ordinary, matter. This includes planets, stars, and life on Earth. The remaining 96 percent of the universe is invisible and consists of dark matter and dark energy, with dark matter constituting about 23 percent. Astrophysical observations confirm its presence throughout the cosmos, where, for example, it plays an important role in the structure of galaxies. However, the particles that make up dark matter remain unknown. Many theories and ongoing experiments are seeking an answer to this open question.
An Interdisciplinary Approach to a Fundamental Question in Particle Physics
To determine the contribution of Z′ bosons to the interaction between electrons and nuclei, which gives rise to the so-called hyperfine structure of atoms, the authors used the MOGON 2 supercomputer at JGU to reinterpret existing results of precision measurements of parity violation in BaF molecules. This study required not only extensive knowledge of the weak interaction and the properties of these beyond-SM bosons but also a solid foundation in atomic, molecular, and nuclear physics, making this a truly interdisciplinary project. “Konstantin Gaul and Lei Cong are new-generation theorists working at the interface of atomic, molecular, and optical physics, as well as particle and nuclear physics,” Budker said. “Having them embedded in a mostly experimental group within HIM and PRISMA++ has led to highly productive collaborations and very interesting and important results, of which this work is just one example.”
In the search for “new physics,” such an approach might shed light on long-standing questions. As Gaul explained, “Because the dense internal environment of polar molecules naturally amplifies subtle physical effects, they act as powerful laboratories for detecting new forces that are otherwise invisible to science.”
The study also established similar bounds by analyzing experiments with the atom cesium-133, which is a more traditional method for studying the interactions between electrons and atomic nuclei. However, in contrast to experiments with atoms, the analysis of diatomic molecules, such as BaF, currently does not depend on nuclear theory. This means that because they are not affected by uncertainties related to nuclear physics, the results can be more precise. “The current study proves that measurements of molecular physics are an emerging tool for new physics, rivaling traditional atomic methods. Our findings demonstrate that future experiments with heavy diatomic species like BaF will boost sensitivity 100-fold, pushing deeper into unexplored territory to hunt for the hidden forces of the universe,” Gaul concluded.
Published in journal: Physical Review Letters
Authors: Konstantin Gau, Lei Cong, and Dmitry Budker
Source/Credit: Johannes Gutenberg-Universität Mainz
Reference Number: phy051126_01
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