NP New Precise Calculation of Nu... | U.S. DOE Office of Science(SC) Official websites use .gov .gov website belongs to an official government organization in the United States. Secure .gov websites use HTTPS lock ) or means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. New Precise Calculation of Nuclear Beta Decays Paves the Way to Uncover Physics Beyond the Standard Model Theorists identify new effects needed to compute the nuclear beta decay rate with a precision of a few parts in ten thousand. Image courtesy of Vincenzo Cirigliano In nuclear beta decay an up quark ‘u’ in a proton converts into an up down quark ‘d,’ turning the proton into a neutron and emitting a positron and a neutrino. This work affects interpretation of beta decay measurements across the chart of nuclides. The Science Quarks are the fundamental building blocks of matter and come in six flavors. The “up” and “down” flavors make up neutrons and protons . Through the weak nuclear force , one quark flavor can transmute into another. However, there’s something strange afoot in this process. Current data and theory indicate that the probabilities of quark transmutation do not add up to 100%, as predicted by the Standard Model of Particle Physics . Instead, there is a deficit of about a part in a thousand. To understand whether this is due to new physics beyond the Standard Model or underestimated uncertainties, a team of nuclear theorists has laid out a new framework needed to extract the up-down quark flavor mixing (the largest mixing) with a precision of a few parts in ten thousand from certain nuclear beta decays . The new framework is designed to track the subtle quantum-mechanical interplay between the strong nuclear force , the electromagnetic interaction , and the weak force that causes the radioactive decay. The Impact The ultimate goal of this research is to confirm the validity of Standard Model down to distances on the order of one millionth of the proton radius or to discover new physics beyond the Standard Model. To do so, scientists must reach high precision in both experiments and theory. By uncovering new effects involving the weak interactions of pairs of neutrons and protons, this work is a key step towards achieving a theoretical uncertainty of few parts in ten thousand in the predictions of nuclear beta decay rates. Researchers are applying the new framework in state-of-the-art calculations of the structure of atomic nuclei Summary Precision studies of the beta disintegration of atomic nuclei provide stringent tests of the weak nuclear force, encoded in the Standard Model , and probe the existence of as yet undiscovered particles and forces. State-of-the-art studies point to a discrepancy between experimental data and the expectations of the Standard-Model. Could this be a signal of new physics beyond the Standard Model? To answer this question, a team of six nuclear theorists from three universities and one national laboratory has developed a new framework to compute the rate for nuclear beta decays with a precision of a few parts in ten thousand. Along the way, the team identified previously unaccounted effects that arise from the interplay of the strong, weak, and electromagnetic forces. In the future, building on this work and on advanced many-body nuclear calculations will help scientists control uncertainties at the level of a few parts in ten thousand, thus opening the way to uncover possible footprints of new physics in nuclear beta decays. Should the current discrepancy with Standard Model be confirmed, it would point to the existence of new particles of mass up to ten thousand times the proton mass. This mass is far above the direct reach of existing high-energy particle colliders Contact Vincenzo Cirigliano Institute for Nuclear Theory, University of Washington cirigv@uw.edu Funding This research was supported by the Department of Energy Office of Science, Office of Nuclear Physics and Office of High Energy Physics; the Laboratory Directed Research and Development program at Los Alamos National Laboratory; the National Science Foundation; the Dutch Research Council; and the Swiss National Science Foundation. Publications Cirigliano, V., et al ., Radiative corrections to superallowed β decays in effective field theory Physical Review Letters 133 , 21 (2024). [DOI:10.1103/PhysRevLett.133.211801] Cirigliano, V., et al ., Ab-initio electroweak corrections to superallowed β decays and their impact on V ud Physical Review C 110 , 5 (2024). The paper was selected as an editor’s suggestion . [DOI: 10.1103/PhysRevC.110.055502] Highlight Categories Program: HEP NP Performer: University DOE Laboratory Physicists Propose a New Kind of Laser That Would Fire Neutrinos A potential tool could use Bose Einstein condensates to produce intense beams of neutrinos. KATRIN Narrows Down the Range of Neutrinos’ Mass A direct search shows that neutrinos are at least a million times lighter than electrons. Contact Nuclear Physics Address U.S. Department of Energy NP/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 Phone Tel 301-903-3613 Email Send us a message sc.np@science.doe.gov Read more about Join Mailing List Signup for the Office of Science’s GovDelivery email service , and check the box for the Nuclear Physics Program in your subscriber preferences. Top Leaving Office of Science The link you have requested will take you to a website outside the Office of Science. Please click the following link to continue: Thank you for visiting our site. 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