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Analog-antianalog isospin mixing in K47 β− decay

Physical Review C 2024年第5期109卷 L052501-L052501页

作者： Brian Kootte H. Gallop C. Luktuke J. C. McNeil A. Gorelov D. G. Melconian J. Klimo B. M. Vargas-Calderon J. A. Behr 4004 Wesbrook Mall Vancouver B.C. V6T 2A3 Canada Department of Physics and Astronomy 200 University Ave W Waterloo Ontario N2L 3G1 Canada Department of Physics and Astronomy 6224 Agricultural Road Vancouver B.C. V6T 1Z1 Canada Cyclotron Institute Department of Physics and Astronomy

We have measured the isospin mixing of the Iπ=1/2+, Ex=2.599 MeV state in nearly doubly magic Ca47 with the isobaric analog 1/2+ state of K47. Using the TRIUMF atom trap for β decay, we have measured a nonzero asymmetry of the progeny Ca47 with respect to the initial K47 spin polarization, which together with the β asymmetry implies a nonzero ratio of Fermi to Gamow-Teller matrix elements y=0.098±0.037 for the 1/2+→1/2+ transition. Interpreting y as mixing between this state and the isobaric analog state implies a Coulomb matrix element magnitude 101±37 keV. This relatively large matrix element supports a model from the literature of analog-antianalog isospin mixing, which predicts large matrix elements in cases involving excess neutrons over protons occupying more than one major shell. The result supports pursuing a search for time-reversal odd, parity-even, isovector interactions using a correlation in K47β decay.

关键词： Beta decay electroweak interactions in nuclear physics nuclear decay nuclear tests of fundamental interactions 39 ≤ A ≤ 58

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First direct Be7 electron-capture Q-value measurement toward high-precision searches for neutrino physics beyond the Standard Model

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Physical Review C 2024年第2期109卷 L022501-L022501页

作者： R. Bhandari G. Bollen T. Brunner N. D. Gamage A. Hamaker Z. Hockenbery M. Horana Gamage D. K. Keblbeck K. G. Leach D. Puentes M. Redshaw R. Ringle S. Schwarz C. S. Sumithrarachchi I. Yandow Department of Physics Central Michigan University Mount Pleasant Michigan 48859 USA Facility for Rare Isotope Beams East Lansing Michigan 48824 USA Department of Physics and Astronomy Michigan State University East Lansing Michigan 48824 USA Department of Physics McGill University Montréal Québec Canada H3A 2T8 TRIUMF Vancouver British Columbia Canada V6T 2A3 Department of Physics Colorado School of Mines Golden Colorado 80401 USA

We report the first direct measurement of the nuclear electron-capture (EC) decay Q value of Be7→Li7 via high-precision Penning trap mass spectrometry (PTMS). This was performed using the LEBIT Penning trap located at the National Superconducting Cyclotron Laboratory/Facility for Rare Isotope Beams (NSCL/FRIB) using the newly commissioned Batch-Mode Ion-Source (BMIS) to deliver the unstable Be+7 samples. With a measured value of QEC=861.963(23) keV, this result is three times more precise than any previous determination of this quantity. This improved precision and accuracy of the Be7 EC decay Q value is critical for ongoing experiments that measure the recoiling nucleus in this system as a signature to search for beyond the Standard Model (BSM) neutrino physics using Be7-doped superconducting sensors. This experiment has extended LEBIT capabilities, using the first low-energy beam delivered by BMIS at FRIB for PTMS, as well as measuring the lightest-mass isotopes so far with LEBIT.

关键词： Beta decay Binding energy & masses electroweak interactions in nuclear physics nuclear tests of fundamental interactions 6 ≤ A ≤ 19 Spectrometers & spectroscopic techniques

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Proton-Proton Fusion and Tritium β Decay from Lattice Quantum Chromodynamics

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Physical Review Letters 2017年第6期119卷 062002-062002页

作者： Martin J. Savage Phiala E. Shanahan Brian C. Tiburzi Michael L. Wagman Frank Winter Silas R. Beane Emmanuel Chang Zohreh Davoudi William Detmold Kostas Orginos Institute for Nuclear Theory University of Washington Seattle Washington 98195-1550 USA Kavli Institute for Theoretical Physics University of California Santa Barbara California 93106 USA Center for Theoretical Physics Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Department of Physics The City College of New York New York New York 10031 USA Graduate School and University Center The City University of New York New York New York 10016 USA RIKEN BNL Research Center Brookhaven National Laboratory Upton New York 11973 USA Department of Physics University of Washington Box 351560 Seattle Washington 98195 USA Jefferson Laboratory 12000 Jefferson Avenue Newport News Virginia 23606 USA Department of Physics College of William and Mary Williamsburg Virginia 23187-8795 USA

The nuclear matrix element determining the pp→de+ν fusion cross section and the Gamow-Teller matrix element contributing to tritium β decay are calculated with lattice quantum chromodynamics for the first time. Using a new implementation of the background field method, these quantities are calculated at the SU(3) flavor–symmetric value of the quark masses, corresponding to a pion mass of mπ∼806 MeV. The Gamow-Teller matrix element in tritium is found to be 0.979(03)(10) at these quark masses, which is within 2σ of the experimental value. Assuming that the short-distance correlated two-nucleon contributions to the matrix element (meson-exchange currents) depend only mildly on the quark masses, as seen for the analogous magnetic interactions, the calculated pp→de+ν transition matrix element leads to a fusion cross section at the physical quark masses that is consistent with its currently accepted value. Moreover, the leading two-nucleon axial counterterm of pionless effective field theory is determined to be L1,A=3.9(0.2)(1.0)(0.4)(0.9) fm3 at a renormalization scale set by the physical pion mass, also agreeing within the accepted phenomenological range. This work concretely demonstrates that weak transition amplitudes in few-nucleon systems can be studied directly from the fundamental quark and gluon degrees of freedom and opens the way for subsequent investigations of many important quantities in nuclear physics.

关键词： electroweak interactions in nuclear physics Lattice QCD nuclear reactions QCD in nuclear reactions Quantum chromodynamics

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nuclear-Level Effective Theory of μ→e Conversion

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Physical Review Letters 2023年第13期130卷 131901-131901页

作者： Evan Rule W. C. Haxton Kenneth McElvain Department of Physics University of California Berkeley California 94720 USA Lawrence Berkeley National Laboratory Berkeley California 94720 USA

The Mu2e and COMET μ→e conversion experiments are expected to significantly advance limits on new sources of charged lepton flavor violation. Almost all theoretical work in the field has focused on just two operators. However, general symmetry arguments lead to a μ→e conversion rate with six response functions, each of which, in principle, is observable by varying nuclear properties of targets. We construct a nucleon-level nonrelativistic effective theory (NRET) to clarify the microscopic origin of these response functions and to relate rate measurements in different targets. This exercise identifies three operators and their small parameters that control the NRET operator expansion. We note inconsistencies in past treatments of these parameters. The NRET is technically challenging, involving 16 operators, several distorted electron partial waves, bound muon upper and lower components, and an exclusive nuclear matrix element. We introduce a trick for treating the electron Coulomb effects accurately, which enables us to include all of these effects while producing transition densities whose one-body matrix elements can be evaluated analytically, greatly simplifying the nuclear physics. We derive bounds on operator coefficients from existing and anticipated μ→e conversion experiments. We discuss how similar NRET formulations have impacted dark matter phenomenology, noting that the tools this community has developed could be adapted for charged lepton flavor violation studies.

关键词： Electron & muon capture electroweak interactions in nuclear physics nuclear tests of fundamental interactions Particle interactions

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Ab Initio Computation of the Longitudinal Response Function in Ca40

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Physical Review Letters 2021年第7期127卷 072501-072501页

作者： J. E. Sobczyk B. Acharya S. Bacca G. Hagen Institut für Kernphysik and PRISMA+ Cluster of Excellence Johannes Gutenberg-Universität 55128 Mainz Germany Helmholtz-Institut Mainz Johannes Gutenberg-Universität Mainz D-55099 Mainz Germany Physics Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA Department of Physics and Astronomy University of Tennessee Knoxville Tennessee 37996 USA

We present a consistent ab initio computation of the longitudinal response function RL in Ca40 using the coupled-cluster and Lorentz integral transform methods starting from chiral nucleon-nucleon and three-nucleon interactions. We validate our approach by comparing our results for RL in He4 and the Coulomb sum rule in Ca40 against experimental data and other calculations. For RL in Ca40 we obtain a very good agreement with experiment in the quasielastic peak up to intermediate momentum transfers, and we find that final state interactions are essential for an accurate description of the data. This work presents a milestone towards ab initio computations of neutrino-nucleus cross sections relevant for experimental long-baseline neutrino programs.

关键词： electroweak interactions in nuclear physics Electrons Neutrinos Ab initio calculations nuclear many-body theory

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nuclear spin-dependent parity-violating effects in light polyatomic molecules

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Physical Review A 2020年第5期102卷 052828-052828页

作者： Yongliang Hao Petr Navrátil Eric B. Norrgard Miroslav Iliaš Ephraim Eliav Rob G. E. Timmermans Victor V. Flambaum Anastasia Borschevsky Van Swinderen Institute for Particle Physics and Gravity Faculty of Science and Engineering University of Groningen Nijenborgh 4 9747 AG Groningen The Netherlands TRIUMF 4004 Wesbrook Mall Vancouver British Columbia V6T 2A3 Canada Joint Quantum Institute National Institute of Standards and Technology and University of Maryland Gaithersburg Maryland 20899 USA Department of Chemistry Faculty of Natural Sciences Matej Bel University Tajovského 40 97401 Banská Bystrica Slovakia School of Chemistry Tel Aviv University 6997801 Tel Aviv Israel School of Physics University of New South Wales Sydney New South Wales 2052 Australia

Measurements of nuclear spin-dependent parity-violating (NSD-PV) effects provide an excellent opportunity to test nuclear models and to search for physics beyond the Standard Model. Molecules possess closely spaced states with opposite parity which may be easily tuned to degeneracy to greatly enhance the observed parity-violating effects. A high-sensitivity measurement of NSD-PV effects using light triatomic molecules is in preparation [E. B. Norrgard et al., Commun. Phys. 2, 77 (2019)]. Importantly, by comparing these measurements in light nuclei with prior and ongoing measurements in heavier systems, the contribution to NSD-PV from Z0-boson exchange between the electrons and the nuclei may be separated from the contribution of the nuclear anapole moment. Furthermore, light triatomic molecules offer the possibility to search for new particles, such as the postulated Z′ boson. In this work, we detail a sensitive measurement scheme and present high-accuracy molecular and nuclear calculations needed for interpretation of NSD-PV experiments on triatomic molecules composed of light elements, Be, Mg, N, and C. The ab initio nuclear structure calculations, performed within the no-core shell model provide a reliable prediction of the magnitude of different contributions to the NSD-PV effects in the four nuclei. These results differ significantly from the predictions of the standard single-particle model and highlight the importance of including many-body effects in such calculations. In order to extract the NSD-PV contributions from measurements, a parity-violating interaction parameter WPV, which depends on the molecular structure, needs to be known with a high accuracy. We have calculated these parameters for the triatomic molecules of interest using the relativistic coupled-cluster approach. In order to facilitate the interpretation of future experiments we provide uncertainties on the calculated parameters. A scheme for measurement using laser-cooled polyatomic molecu

关键词： Electronic structure of atoms & molecules electroweak interactions in nuclear physics Laser spectroscopy

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Precision Measurement of the Beam-Normal Single-Spin Asymmetry in Forward-Angle Elastic Electron-Proton Scattering

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Physical Review Letters 2020年第11期125卷 112502-112502页

作者： D. Androić D. S. Armstrong A. Asaturyan K. Bartlett J. Beaufait R. S. Beminiwattha J. Benesch F. Benmokhtar J. Birchall R. D. Carlini J. C. Cornejo S. Covrig Dusa M. M. Dalton C. A. Davis W. Deconinck J. F. Dowd J. A. Dunne D. Dutta W. S. Duvall M. Elaasar W. R. Falk J. M. Finn T. Forest C. Gal D. Gaskell M. T. W. Gericke J. Grames V. M. Gray K. Grimm F. Guo J. R. Hoskins D. Jones M. K. Jones R. T. Jones M. Kargiantoulakis P. M. King E. Korkmaz S. Kowalski J. Leacock J. P. Leckey A. R. Lee J. H. Lee L. Lee S. MacEwan D. Mack J. A. Magee R. Mahurin J. Mammei J. W. Martin M. J. McHugh D. Meekins J. Mei K. E. Mesick R. Michaels A. Micherdzinska A. Mkrtchyan H. Mkrtchyan N. Morgan A. Narayan L. Z. Ndukum V. Nelyubin Nuruzzaman W. T. H. van Oers V. F. Owen S. A. Page J. Pan K. D. Paschke S. K. Phillips M. L. Pitt R. W. Radloff J. F. Rajotte W. D. Ramsay J. Roche B. Sawatzky T. Seva M. H. Shabestari R. Silwal N. Simicevic G. R. Smith P. Solvignon D. T. Spayde A. Subedi R. Subedi R. Suleiman V. Tadevosyan W. A. Tobias V. Tvaskis B. Waidyawansa P. Wang S. P. Wells S. A. Wood S. Yang P. Zang S. Zhamkochyan University of Zagreb Zagreb HR 10002 Croatia William & Mary Williamsburg Virginia 23185 USA A. I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Yerevan 0036 Armenia Thomas Jefferson National Accelerator Facility Newport News Virginia 23606 USA Ohio University Athens Ohio 45701 USA Louisiana Tech University Ruston Louisiana 71272 USA Duquesne University Pittburgh Pennsylvania 15282 USA University of Manitoba Winnipeg Manitoba R3T2N2 Canada University of Virginia Charlottesville Virginia 22903 USA TRIUMF Vancouver British Columbia V6T2A3 Canada Mississippi State University Mississippi State Mississippi 39762 USA Virginia Polytechnic Institute & State University Blacksburg Virginia 24061 USA Southern University at New Orleans New Orleans Louisiana 70126 USA Idaho State University Pocatello Idaho 83209 USA Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA University of Connecticut Storrs-Mansfield Connecticut 06269 USA University of Northern British Columbia Prince George British Columbia V2N4Z9 Canada University of Winnipeg Winnipeg Manitoba R3B2E9 Canada George Washington University Washington DC 20052 USA Rutgers The State University of New Jersey Piscataway New Jersey 088754 USA Hampton University Hampton Virginia 23668 USA University of New Hampshire Durham New Hampshire 03824 USA Hendrix College Conway Arkansas 72032 USA Syracuse University Syracuse New York 13244 USA

A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision measurement of the beam-normal single-spin asymmetry in elastic electron-proton scattering with a mean scattering angle of θlab=7.9° and a mean energy of 1.149 GeV. The asymmetry result is Bn=−5.194±0.067(stat)±0.082 (syst) ppm. This is the most precise measurement of this quantity available to date and therefore provides a stringent test of two-photon exchange models at far-forward scattering angles (θlab→0) where they should be most reliable.

关键词： electroweak interactions in nuclear physics electroweak radiative corrections Form factors Lepton induced nuclear reactions Polarization phenomena

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Limits on the Existence of sub-MeV Sterile Neutrinos from the Decay of Be7 in Superconducting Quantum Sensors

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Physical Review Letters 2021年第2期126卷 021803-021803页

作者： S. Friedrich G. B. Kim C. Bray R. Cantor J. Dilling S. Fretwell J. A. Hall A. Lennarz V. Lordi P. Machule D. McKeen X. Mougeot F. Ponce C. Ruiz A. Samanta W. K. Warburton K. G. Leach Lawrence Livermore National Laboratory Livermore California 94550 USA Department of Physics Colorado School of Mines Golden Colorado 80401 USA STAR Cryoelectronics LLC Santa Fe New Mexico 87508 USA TRIUMF Vancouver British Columbia V6T 2A3 Canada Department of Physics and Astronomy McMaster University Hamilton Ontario L8S 4M1 Canada Université Paris-Saclay CEA List Laboratoire National Henri Becquerel (LNE-LNHB) F-91120 Palaiseau France Department of Physics Stanford University Stanford California 94305 USA XIA LLC Hayward California 94544 USA

Sterile neutrinos are natural extensions to the standard model of particle physics and provide a possible portal to the dark sector. We report a new search for the existence of sub-MeV sterile neutrinos using the decay-momentum reconstruction technique in the decay of Be7. The experiment measures the total energy of the Li7 daughter atom from the electron capture decay of Be7 implanted into sensitive superconducting tunnel junction (STJ) quantum sensors. This first experiment presents data from a single STJ operated at a low count rate for a net total of 28 days, and provides exclusion limits on sterile neutrinos in the mass range from 100 to 850 keV that improve upon previous work by up to an order of magnitude.

关键词： Electron & muon capture electroweak interactions in nuclear physics nuclear tests of fundamental interactions Quantum sensing Neutrinos Sterile neutrinos 6 ≤ A ≤ 19 Precision measurements Radiation detectors

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Measuring nuclear-spin-dependent parity violation with molecules: Experimental methods and analysis of systematic errors

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Physical Review A 2018年第4期97卷 042101-042101页

作者： Emine Altuntaş Jeffrey Ammon Sidney B. Cahn David DeMille Department of Physics Yale University P.O. Box 208120 New Haven 06520 CT United States Joint Quantum Institute National Institute of Standards and Technology University of Maryland Gaithersburg 20899 MD United States Lincoln Laboratory Massachusetts Institute of Technology Lexington 02420 MA United States

nuclear-spin-dependent parity violation (NSD-PV) effects in atoms and molecules arise from Z0 boson exchange between electrons and the nucleus and from the magnetic interaction between electrons and the parity-violating nuclear anapole moment. It has been proposed to study NSD-PV effects using an enhancement of the observable effect in diatomic molecules [D. DeMille et al., Phys. Rev. Lett. 100, 023003 (2008)]. Here we demonstrate highly sensitive measurements of this type, using the test system Ba138F19. We show that systematic errors associated with our technique can be suppressed to at least the level of the present statistical sensitivity. With ∼170 h of data, we measure the matrix element W of the NSD-PV interaction with uncertainty δW/(2π)<0.7 Hz for each of two configurations where W must have different signs. This sensitivity would be sufficient to measure NSD-PV effects of the size anticipated across a wide range of nuclei.

关键词： electroweak interactions in nuclear physics nuclear spin & parity P-symmetry Parity

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First Observation of Cyclotron Radiation from MeV-Scale e± following nuclear β Decay

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Physical Review Letters 2023年第8期131卷 082502-082502页

作者： W. Byron H. Harrington R. J. Taylor W. DeGraw N. Buzinsky B. Dodson M. Fertl A. García G. Garvey B. Graner M. Guigue L. Hayen X. Huyan K. S. Khaw K. Knutsen D. McClain D. Melconian P. Müller E. Novitski N. S. Oblath R. G. H. Robertson G. Rybka G. Savard E. Smith D. D. Stancil M. Sternberg D. W. Storm H. E. Swanson J. R. Tedeschi B. A. VanDevender F. E. Wietfeldt A. R. Young X. Zhu Department of Physics University of Washington Seattle Washington 98195 USA Center for Nuclear Physics and Astrophysics University of Washington Seattle Washington 98195 USA Physics Department North Carolina State University Raleigh North Carolina 27695 USA The Triangle Universities Nuclear Laboratory Durham North Carolina 27708 USA Institute for Physics Johannes-Gutenberg University Mainz 55128 Mainz Germany Pacific Northwest National Laboratory Richland Washington 99352 USA Department of Physics and Astronomy Texas A&M University College Station Texas 77843 USA Cyclotron Institute Texas A&M University College Station Texas 77843 USA Physics Division Argonne National Laboratory 9700 South Cass Avenue Argonne Illinois 60439 USA Department of Electrical and Computer Engineering North Carolina State University Raleigh North Carolina 27695 USA Department of Physics and Engineering Physics Tulane University New Orleans Louisiana 70118 USA

We present an apparatus for detection of cyclotron radiation yielding a frequency-based β± kinetic energy determination in the 5 keV to 2.1 MeV range, characteristic of nuclear β decays. The cyclotron frequency of the radiating β particles in a magnetic field is used to determine the β energy precisely. Our work establishes the foundation to apply the cyclotron radiation emission spectroscopy (CRES) technique, developed by the Project 8 Collaboration, far beyond the 18-keV tritium endpoint region. We report initial measurements of β−’s from He6 and β+’s from Ne19 decays to demonstrate the broadband response of our detection system and assess potential systematic uncertainties for β spectroscopy over the full (MeV) energy range. To our knowledge, this is the first direct observation of cyclotron radiation from individual highly relativistic β’s in a waveguide. This work establishes the application of CRES to a variety of nuclei, opening its reach to searches for new physics beyond the TeV scale via precision β-decay measurements.

关键词： Beta decay electroweak interactions in nuclear physics Neutron physics nuclear structure & decays Symmetries Radiation detectors Radioactive beams

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