Nuclear physics

  • Article |

    Electron scattering measurements are shown to reproduce only qualitatively state-of-the-art lepton–nucleus energy reconstruction models, indicating that improvements to these particle-interaction models are required to ensure the accuracy of future high-precision neutrino oscillation experiments.

    • M. Khachatryan
    • , A. Papadopoulou
    •  & S. Gardiner
  • Article |

    γ-ray spectroscopy experiments on the origin of spin in the products of nuclear fission of spin-zero nuclei suggest that the fission fragments acquire their spin after scission, rather than before.

    • J. N. Wilson
    • , D. Thisse
    •  & S. Ziliani
  • Article |

    Quark–antiquark annihilation measurements provide a precise determination of the ratio of down and up antiquarks within protons as a function of momentum, which confirms the asymmetry between the abundance of down and up antiquarks.

    • J. Dove
    • , B. Kerns
    •  & Z. Ye
  • Article
    | Open Access

    Suitably shaped X-ray pulses are used to coherently steer the quantum dynamics of atoms’ nuclei rather than their electrons, with few-zeptosecond temporal stability of the phase control.

    • Kilian P. Heeg
    • , Andreas Kaldun
    •  & Jörg Evers
  • Article
    | Open Access

    The 2S–2P transitions in muonic helium-4 ions are measured using laser spectroscopy and used to obtain an α-particle charge-radius value five times more precise than that from electron scattering.

    • Julian J. Krauth
    • , Karsten Schuhmann
    •  & Franz Kottmann
  • Article
    | Open Access

    Correlations in momentum space between hadrons created by ultrarelativistic proton–proton collisions at the CERN Large Hadron Collider provide insights into the strong interaction, particularly the short-range dynamics of hyperons—baryons that contain strange quarks.

    • S. Acharya
    • , D. Adamová
    •  & N. Zurlo
  • Article |

    A mechanistic explanation for the origin of the neutron dripline shows that nuclei accommodate the addition of neutrons by becoming increasingly ellipsoidal, up to a maximum number of neutrons, reconciling theory and experiments.

    • Naofumi Tsunoda
    • , Takaharu Otsuka
    •  & Hideki Ueno
  • Article |

    Ionizing radiation from environmental radioactivity and cosmic rays increases the density of broken Cooper pairs in superconducting qubits, reducing their coherence times, but can be partially mitigated by lead shielding.

    • Antti P. Vepsäläinen
    • , Amir H. Karamlou
    •  & William D. Oliver
  • Article
    | Open Access

    Measurements of low-energy electronic states of radium monofluoride validate predictions of the use of this short-lived radioactive molecule in exploring fundamental physics and provide evidence of its suitability for laser cooling.

    • R. F. Garcia Ruiz
    • , R. Berger
    •  & X. F. Yang
  • Article |

    Observations of the decay of 73Sr, when compared to its mirror nucleus 73Br, indicate that the spin assignment of their ground states differ, demonstrating mirror-symmetry violation.

    • D. E. M. Hoff
    • , A. M. Rogers
    •  & S. Waniganeththi
  • Article |

    High-energy electron scattering that can isolate pairs of nucleons in high-momentum configurations reveals a transition to spin-independent scalar forces at small separation distances, supporting the use of point-like nucleon models to describe dense nuclear systems.

    • A. Schmidt
    • , J. R. Pybus
    •  & X. Zheng
  • Article
    | Open Access

    Ionization cooling, a technique that delivers high-brightness muon beams for the study of phenomena at energy scales beyond those of the Large Hadron Collider, is demonstrated by the Muon Ionization Cooling Experiment.

    • M. Bogomilov
    • , R. Tsenov
    •  & C. Heidt
  • Article |

    A magnetic-spectrometer-free method for electron–proton scattering data reveals a proton charge radius 2.7 standard deviations smaller than the currently accepted value from electron–proton scattering, yet consistent with other recent experiments.

    • W. Xiong
    • , A. Gasparian
    •  & Z. W. Zhao
  • Article |

    Reanalysis of the spectra associated with the merger of two neutron stars identifies strontium, spectroscopically establishing the origin of the heavy elements created by rapid neutron capture and proving that neutron stars comprise neutron-rich matter.

    • Darach Watson
    • , Camilla J. Hansen
    •  & Elena Pian
  • Letter |

    Excitation to the second excited state of 229Th is used to populate the metastable state 229mTh, enabling accurate determination of the isomer’s energy, half-life and excitation linewidth.

    • Takahiko Masuda
    • , Akihiro Yoshimi
    •  & Koji Yoshimura
  • Letter |

    The transition energy of the first excited state of 229Th to the ground state is determined through the measurement of internal conversion electrons to correspond to a wavelength of 149.7 ± 3.1 nanometres.

    • Benedict Seiferle
    • , Lars von der Wense
    •  & Peter G. Thirolf
  • Perspective |

    Three years of investigation by a multi-disciplinary team into claims of ‘cold fusion’ found no evidence that the phenomenon exists, but identified a parameter space potentially worthy of further exploration.

    • Curtis P. Berlinguette
    • , Yet-Ming Chiang
    •  & Matthew D. Trevithick
  • Letter |

    A rare type of supernova—triggered by the collapse of a rapidly rotating single star—could have provided more than 80 per cent of the r-process elements in the Universe.

    • Daniel M. Siegel
    • , Jennifer Barnes
    •  & Brian D. Metzger
  • Letter |

    Simultaneous high-precision measurements of the EMC effect and short-range correlated abundances for several nuclei reveal a universal modification of the structure of nucleons in short-range correlated neutron–proton pairs.

    • B. Schmookler
    • , M. Duer
    •  & X. Zheng
  • Letter |

    The thermal neutron capture cross-section of 88Zr is measured to be 861,000 ± 69,000 barns, the second-largest neutron capture cross-section ever measured.

    • Jennifer A. Shusterman
    • , Nicholas D. Scielzo
    •  & Anton P. Tonchev
  • Review Article |

    By analysing particle production in high-energy nuclear collisions, the phase boundary of strongly interacting matter is located and the phase structure of quantum chromodynamics is elucidated, implying quark–hadron duality.

    • Anton Andronic
    • , Peter Braun-Munzinger
    •  & Johanna Stachel
  • Letter |

    Electron-scattering experiments reveal that the fraction of high-momentum protons in medium-to-heavy nuclei increases considerably with neutron excess, whereas that of high-momentum neutrons decreases slightly, in contrast to shell-model predictions.

    • M. Duer
    • , O. Hen
    •  & Z. W. Zhao
  • Letter |

    Measurement of the asymmetry in the parity-violating scattering of polarized electrons on protons gives the weak charge of the proton as 0.0719 ± 0.0045, in agreement with the standard model.

    • D. Androić
    • , D. S. Armstrong
    •  & S. Zhamkochyan
  • Letter |

    Two singly charmed baryons can fuse into the recently discovered doubly charmed baryon and a neutron through an exothermic reaction analogous to the nuclear fusion between deuterium and tritium.

    • Marek Karliner
    •  & Jonathan L. Rosner
  • Letter |

    Ground-based observations during a thunderstorm provide conclusive evidence of positrons being produced after lightning, confirming that lightning can trigger photonuclear reactions.

    • Teruaki Enoto
    • , Yuuki Wada
    •  & Harufumi Tsuchiya
  • Letter |

    The measurement of an alignment between the angular momentum of a non-central collision between heavy ions and the spin of emitted particles reveals that the fluid produced in the collision is extremely vortical.

    • L. Adamczyk
    • , J. K. Adkins
    •  & M. Zyzak
  • Letter |

    Resonance ionization spectroscopy of nobelium (atomic number 102) reveals its ground-state transition and an upper limit for its ionization potential, paving the way to characterizing even heavier elements via optical spectroscopy.

    • Mustapha Laatiaoui
    • , Werner Lauth
    •  & Alexander Yakushev
  • Letter |

    A new imaging and spectroscopy approach combines the ability of magnetic resonance imaging to manipulate nuclear spins with the high sensitivity of γ-ray detection, enabling a greatly reduced number of nuclei to be used compared to conventional NMR signal detection.

    • Yuan Zheng
    • , G. Wilson Miller
    •  & Gordon D. Cates
  • Review Article |

    Advances in meson spectroscopy can enhance our understanding of how composite objects emerge from the fundamental underlying theory of interacting quarks and gluons, quantum chromodynamics.

    • Matthew R. Shepherd
    • , Jozef J. Dudek
    •  & Ryan E. Mitchell
  • Article |

    Direct detection of the 229Th nuclear clock transition has been achieved, placing direct constraints on transition energy and half-life; these results are a step towards a nuclear clock, nuclear quantum optics and a nuclear laser.

    • Lars von der Wense
    • , Benedict Seiferle
    •  & Peter G. Thirolf
  • Letter |

    An ab initio calculation of alpha–alpha scattering is described for which the number of computational operations scales approximately quadratically with particle number and which uses lattice Monte Carlo simulations and lattice effective field theory, combined with the adiabatic projection method to reduce the eight-body system to a two-cluster system.

    • Serdar Elhatisari
    • , Dean Lee
    •  & Ulf-G. Meißner
  • Letter |

    The interaction between antiprotons, produced by colliding high-energy gold ions, is shown to be attractive, and two important parameters of this interaction are measured, namely the scattering length and the effective range.

    • L. Adamczyk
    • , J. K. Adkins
    •  & M. Zyzak
  • Letter |

    The exotic double-gamma nuclear decay has been observed in cases where the usual single-gamma decay is forbidden, but now a double-gamma decay of excited 137Ba is reported that is in competition with a single-gamma decay.

    • C. Walz
    • , H. Scheit
    •  & V. Yu. Ponomarev
  • Letter
    | Open Access

    The CPT theorem (the assumption that physical laws are invariant under simultaneous charge conjugation, parity transformation and time reversal) is central to the standard model of particle physics; here the charge-to-mass ratio of the antiproton is compared to that of the proton, with a precision of 69 parts per trillion, and the result supports the CPT theorem at the atto-electronvolt scale.

    • S. Ulmer
    • , C. Smorra
    •  & Y. Yamazaki