A New Perspective on the Cosmos: Neutron Decay Interaction and the Concept of Right-Handed Currents

An unstable neutron, when spinning, breaks down into a proton, an electron, and an antineutrino. This happens when a down quark inside the neutron releases a W boson and morphs into an up quark. The intensity of this transformation is adjusted by the transfer of light particles (γ) between charged particles. Image credit goes to Vincenzo Cirigliano, from the Institute for Nuclear Theory.

Unveiling the Connection Between Electromagnetism and Weak Nuclear Force

A surprising effect relating to the interaction between weak and electromagnetic forces in neutron decay has been uncovered by nuclear theorists. This discovery not only modifies our comprehension of neutron decay but also underscores the necessity for detailed calculations of electromagnetic impacts. Moreover, it affects the quest to identify phenomena that could reinstate mirror-reflection symmetry in the cosmos.

The Research

Neutrons are inherently unstable particles outside atomic nuclei, with a lifespan of roughly fifteen minutes. Their disintegration, producing a proton, an electron, and an antineutrino, is attributed to the weak nuclear force. This force is one of the four basic forces in the universe, along with strong force, electromagnetic force, and gravitational force. By juxtaposing experimental outcomes of neutron decay with theoretical forecasts based on weak nuclear force, unexplored interactions can be detected. However, such comparisons demand exceptional precision. A group of nuclear theorists has discovered a novel and relatively significant effect in neutron decay, stemming from the interrelation of weak and electromagnetic forces.

The Significance

The research revealed a change in the strength with which a spinning neutron encounters the weak nuclear force. This revelation bears two primary ramifications. First, since 1956, it has been known that due to the weak force, a system and its mirror image do not respond identically. In simpler terms, mirror reflection symmetry is violated. This research impacts the hunt for new interactions, scientifically termed as “right-handed currents,” which could restore mirror-reflection symmetry in the universe at incredibly short distances of less than one hundred quadrillionths of a centimeter. Secondly, the research underscores the necessity to compute electromagnetic impacts with heightened precision, which mandates the use of advanced high-performance computers in the future.

Synopsis

A group of investigators calculated the influence of electromagnetic interactions on neutron decay resulting from the generation and absorption of photons, the light particles. The group comprised nuclear theorists from various institutions including the University of Washington’s Institute for Nuclear Theory, North Carolina State University, the University of Amsterdam, Los Alamos National Laboratory, and Lawrence Berkeley National Laboratory.

The team applied an advanced technique, the “effective field theory,” which systematically prioritizes the significance of fundamental interactions in phenomena involving strongly interacting particles. They detected a new percent-level shift in the nucleon axial coupling, gA, controlling the decay strength of a spinning neutron. This new correction stems from the generation and absorption of electrically charged pions, the facilitators of the strong nuclear force. Though effective field theory provides an estimate of uncertainties, enhancing the existing precision necessitates advanced calculations on Department of Energy supercomputers. Additionally, the researchers evaluated the influence on the search for right-handed current. They concluded that the experimental data and theory match well after incorporating the new correction, and current uncertainties still leave room for discovering new physics at a relatively low mass scale.

Reference: “Pion-Induced Radiative Corrections to Neutron β Decay” by Vincenzo Cirigliano, Jordy de Vries, Leendert Hayen, Emanuele Mereghetti and André Walker-Loud, 12 September 2022, Physical Review Letters.
DOI: 10.1103/PhysRevLett.129.121801

The Department of Energy Office of Science, Office of Nuclear Physics; the Laboratory Directed Research and Development program at Los Alamos National Laboratory; the National Science Foundation; and the Dutch Research Council financially backed this research.

Frequently Asked Questions (FAQs) about Neutron Decay Interaction

More about Neutron Decay Interaction

• Understanding Neutron Decay
• The Four Fundamental Forces
• The Concept of Mirror-Reflection Symmetry
• An Overview of Effective Field Theory
• Understanding Pion-Induced Radiative Corrections
• Department of Energy’s Role in Scientific Research