Experimental nuclear physics articles within Nature Physics

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• Research Briefing | 03 May 2024

  Mass difference measurements help to determine the neutrino mass

  The Q-value of electron capture in ¹⁶³Ho has been determined with an uncertainty of 0.6 eV c^–2 through a combination of high-precision Penning-trap mass spectrometry and precise atomic physics calculations. This high-precision measurement provides insight into systematic errors in neutrino mass measurements.

• Article
  19 April 2024 | Open Access

  Penning-trap measurement of the Q value of electron capture in ¹⁶³Ho for the determination of the electron neutrino mass

  Electron capture in ¹⁶³Ho can be used to determine the electron neutrino mass. The Q value of this process is crucial for the evaluation of the systematic uncertainty in such a measurement, and a 50-fold improvement is now reported.

  • Christoph Schweiger
  • , Martin Braß
  •  & Klaus Blaum

• News & Views | 09 January 2024

  Pathway to cool hot molecules

  A promising pathway towards the laser cooling of a molecule containing a radioactive atom has been identified. The unique structure of such a molecule means that it can act as a magnifying lens to probe fundamental physics.

  • Steven Hoekstra

• Article | 09 January 2024

  Precision spectroscopy and laser-cooling scheme of a radium-containing molecule

  Measurements of the rovibronic structure of radium monofluoride molecules allow the identification of a laser cooling scheme. This will enable precise tests of fundamental physics, such as searches for parity or time-reversal symmetry violation.

  • S. M. Udrescu
  • , S. G. Wilkins
  •  & C. Zülch

• Article
  01 May 2023 | Open Access

  Mass measurements show slowdown of rapid proton capture process at waiting-point nucleus ⁶⁴Ge

  Rapid proton capture nucleosynthesis stalls at waiting-point nuclides, including ⁶⁴Ge. Precision mass measurements in the vicinity of this nuclide influence state-of-the-art calculations of X-ray bursts from accreting neutron stars.

  • X. Zhou
  • , M. Wang
  •  & S. Zhang

• News & Views | 23 March 2023

  Modified in medium

  The strong interaction is modified in the presence of nuclear matter. An experiment has now quantified with high precision and accuracy the reduction of the order parameter of the system’s chiral symmetry, which is partially restored.

  • Sean Freeman

• Article | 23 March 2023

  Chiral symmetry restoration at high matter density observed in pionic atoms

  In quantum chromodynamics, the condensation of quark–antiquark pairs breaks the chiral symmetry of vacuum. Experiments with pionic tin atoms demonstrate that the symmetry is partially restored at high densities.

  • Takahiro Nishi
  • , Kenta Itahashi
  •  & Koichi Yoshida

• News & Views | 12 December 2022

  The study of the journey of cosmic antimatter

  A potential observation of low-energy antihelium-3 nuclei would have profound impacts on our understanding of the Galaxy. Experiments at particle colliders help us understand how cosmic antimatter travels over long distances before reaching Earth.

  • Aihong Tang

• Article
  12 December 2022 | Open Access

  Measurement of anti-³He nuclei absorption in matter and impact on their propagation in the Galaxy

  Measurements of the inelastic cross section of anti-³He allow the estimation of the transparency of the Milky Way to the propagation of these light antinuclei produced in either cosmic-ray collisions or annihilation of dark-matter particles.

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

• Research Briefing | 17 October 2022

  Testing the theory of the strong force by measuring proton spin polarizabilities

  Measurements of a transversely polarized target were used to probe the spin structure of the proton in the low-energy region where the interactions between the quarks cannot be ignored. These results provide a benchmark for testing our understanding of the strong force.

• Article | 13 October 2022

  Proton spin structure and generalized polarizabilities in the strong quantum chromodynamics regime

  Measurements of the proton’s generalized spin polarizabilities provide discriminating power between effective descriptions of the strong interaction at low energy.

  • D. Ruth
  • , R. Zielinski
  •  & X. Zheng

• Thesis | 15 March 2022

  A slow burn

  • Mark Buchanan

• News & Views | 14 February 2022

  Still too small to be measured

  Although the mass of the electron antineutrino is still eluding direct measurement, the KATRIN experiment with its huge spectrometer has pushed the sensitivity below a billionth of the proton mass.

  • Angelo Nucciotti

• Article
  14 February 2022 | Open Access

  Direct neutrino-mass measurement with sub-electronvolt sensitivity

  In its second measurement campaign, the Karlsruhe Tritium Neutrino experiment achieved a sub-electronvolt sensitivity on the effective electron anti-neutrino mass.

  • M. Aker
  • , A. Beglarian
  •  & G. Zeller

• Research Highlight | 07 December 2021

  Keep the spins spinning

  • Leonardo Benini

• News & Views | 25 November 2021

  No need to decide

  To test the validity of theoretical models, the predictions they make must be compared with experimental data. Instead of choosing one model out of many to describe mass measurements of zirconium, Bayesian statistics allows the averaging of a variety of models.

  • Alessandro Pastore

• Article | 25 November 2021

  Precision mass measurement of lightweight self-conjugate nucleus ⁸⁰Zr

  High-precision mass measurements of exotic zirconium nuclei are reported, and reveal a double-shell closure for the deformed nucleus ⁸⁰Zr, which is more strongly bound than previously thought.

  • A. Hamaker
  • , E. Leistenschneider
  •  & I. T. Yandow

• News & Views | 08 November 2021

  News on the neutron structure

  Precise measurements of the annihilation of an electron–positron pair into a neutron–antineutron pair allow us to take a look inside the neutron to better understand its complex structure.

  • Galina Pakhlova

• Letter | 08 November 2021

  Oscillating features in the electromagnetic structure of the neutron

  Form factors encode the structure of nucleons. Measurements from electron–positron annihilation at BESIII reveal an oscillating behaviour of the neutron electromagnetic form factor, and clarify a long-standing photon–nucleon interaction puzzle.

  • M. Ablikim
  • , M. N. Achasov
  •  & J. H. Zou

• Comment | 28 October 2021

  Young African universities take the lead

  Having long played the role of collaborators with other, more renowned, institutions, historically disadvantaged South African universities are now challenging the status quo — and emerging as leaders.

  • José Nicolás Orce
  •  & Sifiso Ntshangase

• News & Views | 23 September 2021

  Close to the edge

  The tin isotope ¹⁰⁰Sn is key to understanding nuclear stability, but little is known about its properties. Precision measurements of closely related indium isotopes have now pinned down its mass.

  • Nunzio Itaco

• Letter
  23 September 2021 | Open Access

  Mass measurements of ^99–101In challenge ab initio nuclear theory of the nuclide ¹⁰⁰Sn

  Accurate mass measurements of the indium isotopes adjacent to the doubly magic ¹⁰⁰Sn provide critical benchmarks for ab initio theory, which withstands the challenge.

  • M. Mougeot
  • , D. Atanasov
  •  & K. Zuber

• News & Views | 31 May 2021

  Nucleon spins surprise

  Recent measurements of observables related to proton and neutron spin properties at low energies are in disagreement with the available theoretical predictions, and continue to challenge nuclear experimentalists and theorists alike.

  • Mohammad W. Ahmed

• Letter | 31 May 2021

  Measurement of the generalized spin polarizabilities of the neutron in the low-Q² region

  Measurements of observables sensitive to the neutron’s spin precession are extended to a regime that probes distances of the size of the nucleon. They are found to disagree with predictions from chiral effective field theory.

  • Vincent Sulkosky
  • , Chao Peng
  •  & Lingyan Zhu

• Article | 12 April 2021

  Measurement of the proton spin structure at long distances

  Measurements of the proton’s spin structure in experiments scattering a polarized electron beam off polarized protons in regions of low momentum transfer squared test predictions from chiral effective field theory of the strong interaction.

  • X. Zheng
  • , A. Deur
  •  & Z. W. Zhao

• News & Views | 02 April 2021

  Knock-out interpretability

  A detailed analysis of a nucleon-knockout experiment has put forward a methodological roadmap for overcoming ambiguities in the interpretation of the data — promising access to the nuclear wave functions in unstable nuclei.

  • Jan Ryckebusch

• Letter | 29 March 2021

  Unperturbed inverse kinematics nucleon knockout measurements with a carbon beam

  Initial- and final-state interactions distort the kinematics in particle knockout scattering experiments, complicating their interpretation. These effects are suppressed by detecting ¹¹B nuclei in quasi-free scattering of ¹²C ions from hydrogen.

  • M. Patsyuk
  • , J. Kahlbow
  •  & M. Zuev

• News & Views | 28 January 2021

  The case of the exotic isotopes

  With increasing neutron number, the size of a nucleus grows, subject to subtle effects that act as fingerprints of its internal structure. A fresh look at potassium calls for theory to decipher the details.

  • Gianluca Colò

• Letter
  28 January 2021 | Open Access

  Charge radii of exotic potassium isotopes challenge nuclear theory and the magic character of N = 32

  The charge radii of potassium isotopes up to ⁵²K are measured, and show no sign of magicity at 32 neutrons as previously suggested in calcium. The observations are interpreted with coupled cluster and density functional theory calculations.

  • Á. Koszorús
  • , X. F. Yang
  •  & S. G. Wilkins

• Letter | 09 November 2020

  Many-body factorization and position–momentum equivalence of nuclear short-range correlations

  Effects of nucleon–nucleon correlations are studied with the generalized contact formalism and ab initio quantum Monte Carlo calculations. For nuclei from deuteron to ⁴⁰Ca, the many-body nuclear wave function is shown to factorize at short distances.

  • R. Cruz-Torres
  • , D. Lonardoni
  •  & O. Hen

• Article | 18 May 2020

  Direct measurement of the intrinsic electric dipole moment in pear-shaped thorium-228

  The intrinsic dipole moment of ²²⁸Th is reported, from which the degree of the nucleus’s octupole deformation is estimated, suggesting that ²²⁹Th and ²²⁹Pa may be suitable candidates for the search for a permanent atomic electric dipole moment.

  • M. M. R. Chishti
  • , D. O’Donnell
  •  & J. F. Smith

• Letter
  13 April 2020 | Open Access

  Measurement and microscopic description of odd–even staggering of charge radii of exotic copper isotopes

  Isotopes with an odd number of neutrons are usually slightly smaller in size than their even-neutron neighbours. In charge radii of short-lived copper isotopes, a reduction of this effect is observed when the neutron number approaches fifty.

  • R. P. de Groote
  • , J. Billowes
  •  & X. F. Yang

• Letter | 09 March 2020

  Measurement of the mass difference and the binding energy of the hypertriton and antihypertriton

  The STAR collaboration reports a measurement of the mass difference and binding energy of the hypertriton and its antiparticle. This work constrains the hyperon–nucleon interaction and allows us to test the CPT theorem in a nucleus with strangeness.

  • J. Adam
  • , L. Adamczyk
  •  & M. Zyzak

• Research Highlight | 06 February 2020

  An isomeric isotope

  • Stefanie Reichert

• Article | 27 January 2020

  Deeply virtual Compton scattering off the neutron

  The internal structure of the neutron has now been probed by highly energetic photons scattering off it. Combined with previous results for protons, these measurements reveal the contributions of quark flavours to the nucleon structure.

  • M. Benali
  • , C. Desnault
  •  & P. Zhu

• Research Highlight | 04 November 2019

  Of all shapes

  • Stefanie Reichert

• Research Highlight | 03 September 2019

  Photons in the periphery

  • Stefanie Reichert

• News & Views | 12 August 2019

  Nearly perfect quark–gluon fluid

  A statistical analysis of data from ultra-relativistic heavy-ion collisions has uncovered the specific viscosities of the quark–gluon plasma — suggesting that the hottest matter in the current Universe behaves like a near-perfect fluid.

  • Kari J. Eskola

• Letter | 12 August 2019

  Bayesian estimation of the specific shear and bulk viscosity of quark–gluon plasma

  As the quark–gluon plasma is a short-lived state of matter, its properties cannot be measured directly. A Bayesian parameter estimation method now provides a reliable estimation of the temperature-dependent specific shear and bulk viscosities.

  • Jonah E. Bernhard
  • , J. Scott Moreland
  •  & Steffen A. Bass

• News & Views | 29 July 2019

  Fireball spectroscopy

  The visible mass in the Universe emerged when hadrons — the building blocks of atomic nuclei — formed from a hot fireball made of quarks and gluons. This mechanism has now been investigated in baryon-rich matter at relatively low temperatures.

  • Ralf Rapp

• Article | 29 July 2019

  Probing dense baryon-rich matter with virtual photons

  Virtual photons emitted from strong-interaction matter created in relativistic heavy-ion collisions decay into electron–positron pairs, which provide information about the system’s properties.

  • J. Adamczewski-Musch
  • , O. Arnold
  •  & P. Zumbruch

• Research Highlight | 03 June 2019

  It’s magic

  • Stefanie Reichert

• Research Highlight | 01 April 2019

  The size of the proton

  • Stefanie Reichert

• News & Views | 18 February 2019

  Zirconium isotope found to be a neutron poison

  Zirconium alloys are widely used as cladding material in nuclear reactors due to their neutron transparency. Now, it is shown that ⁸⁸Zr has a surprisingly high neutron capture cross-section exceeding that of other zirconium isotopes by six orders of magnitude.

  • Stephan Heinitz
  •  & Ulli Köster

• Letter | 11 February 2019

  Proton superfluidity and charge radii in proton-rich calcium isotopes

  Spectral study on ^36,37,38Ca isotopes and calculations based on density functional theory reveal the interplay between charge radii and nucleonic pairing correlations.

  • A. J. Miller
  • , K. Minamisono
  •  & J. Watkins

• Letter | 21 January 2019

  Interplay between nuclear shell evolution and shape deformation revealed by the magnetic moment of ⁷⁵Cu

  The magnetic moment of the neutron-rich exotic ⁷⁵Cu nucleus is measured using rare isotope beams with a high spin alignment, clarifying how the evolution of the nuclear shell and the shape deformations are connected.

  • Y. Ichikawa
  • , H. Nishibata
  •  & X. F. Yang

• News & Views | 01 October 2018

  Mercurial shapes

  Mercury isotopes are unique in exhibiting dramatic differences in their nuclear shapes. The analysis of over more than twenty Hg isotopes now shows that this follows from the influence of single-particle effects on the collective properties of a nucleus.

  • Paul Cottle
  •  & Kirby Kemper

• Letter | 01 October 2018

  Characterization of the shape-staggering effect in mercury nuclei

  Spectroscopy and shell model calculations reveal the ¹⁸¹Hg isotope as the endpoint of the shape-staggering of Hg nuclei, a consequence of neutron removal which arises from the interplay of single-particle and collective degrees of freedom.

  • B. A. Marsh
  • , T. Day Goodacre
  •  & K. Zuber

• Measure for Measure | 02 May 2018

  Balancing energy and mass with neutrons

  Michael Jentschel and Klaus Blaum explain why the most famous equation of physics needs checking — and how to do it.

  • Michael Jentschel
  •  & Klaus Blaum

• Article
  14 August 2017 | Open Access

  Evidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHC

  Quantum electrodynamics predicts a rare process in which light is scattered by light. The ATLAS Collaboration reports signs of this elusive effect in the collisions of ultra-relativistic lead ions.

  • M. Aaboud
  • , G. Aad
  •  & L. Zwalinski