2015 Impact factor 1.223
Condensed Matter and Complex Systems

EPJ A Highlight - Open refereed paper reveals how to study unstable radioactive nuclei’s dual traits

alt
HIE-ISOLDE production yields..

HIE-ISOLDE acceleration of radioactive beams to peer into the dual state of matter unique to nuclei

Radioactive nuclides, found within an atom's core, all share a common feature: they have too many or too few neutrons to be stable. In a new review published in EPJ A, Maria Jose Borges and Karsten Riisager explain how overcoming technical difficulties in accelerating such radioactive nuclei beams can help push back the boundaries of nuclear physics research. This fascinating topic is the first EPJ A paper to be subjected to an open referee process, whereby the referee's comments are included.

Read more...

EPJ A Highlight - Breaking up: a convoluted drama at nuclear scale, too

alt
Schematic distribution of the breakup.

Pursuing a detective's approach to carbon atom breakup yields clues relevant to fusion reactions and astrophysics phenomena

Regardless of the scenario, breaking up is dramatic. Take for example the case of carbon (12C) splitting into three nuclei of helium. Until now, due to the poor quality of data and limited detection capabilities, physicists did not know whether the helium fragments were the object of a direct breakup in multiple fragments up front or were formed in a sequence of successive fragmentations. The question has been puzzling physicists for some time. Now, scientists from Denmark's Aarhus University have used a state-of-the-art detector capable of measuring, for the first time, the precise disintegration of the 12C into three helium nuclei. Their findings, released in a study published in EPJ A, reveal a sequence of fragmentations, relevant to developing a specific kind of fusion reactions and in astrophysics.

Read more...

EPJ A Highlight - Germanium detectors get position sensitive

Interaction positions determined by the pulse shape analysis of AGATA and the AGATA spectrometer at GANIL (picture by P. Lecomte).

High purity germanium detectors have grown into the most popular devices within the field of gamma ray spectroscopy. The sensitive part of these detectors consist of the largest, purest and monocrystalline semi-conductors used on earth. In the past Ge, detectors were famous for their outstanding energy resolution and timing information for electromagnetic radiation, especially in the field of nuclear physics and nuclear astrophysics. Recently the introduction of digital data acquisition systems and the segmentation of the Ge crystals opened up new opportunities. The interaction position of the gamma rays inside the detector volume provides new additional information by means of the pulse shape of the various signals. In this way, the Ge detector becomes a position sensitive device and allows for a novel detection method called gamma-ray tracking.

Read more...

EPJ A Highlight - New approach to nuclear structure, freely available

Extraction of the excitation energy of the ½- state of lithium ( 7Li ) using the dependence on the harmonic oscillator frequency ω.

Use of relative coordinates in nuclear structure calculations helps reduce the amount of computational power required

The atomic nucleus is highly complex. This complexity partly stems from the nuclear interactions in atomic nuclei, which induce strong correlations between the elementary particles, or nucleons, that constitute the heart of the atom. The trouble is that understanding this complexity often requires a tremendous amount of computational power. In a new study published in EPJ A, Susanna Liebig from Forschungszentrum Jülich, Germany, and colleagues propose a new approach to nuclear structure calculations. The results are freely available to the nuclear physicists’ community so that other groups can perform their own nuclear structure calculations, even if they have only limited computational resources.

Read more...

EPJ A Managing Editor Reviews Ulf-G. Meißner receives 2016 Lise Meitner Prize

alt
Prof. Ulf-G.Meißner

The Nuclear Physics Division of the EPS awards the prestigious Lise Meitner Prize every alternate year to one or several individuals for outstanding work in the fields of experimental, theoretical or applied nuclear science. Professor Ulf-G.Meißner, Universität Bonn and Forschungszentrum Jülich, Germany, Managing Editor for Reviews and former Editor-in-Chief of EPJ A, receives the 2016 Lise Meitner Prize “for his developments and applications of effective field theories in hadron and nuclear physics, that allowed for systematic and precise investigations of the structure and dynamics of nucleons and nuclei based on Quantum Chromodynamics”.

Read more...

EPJ A Highlight - Nuclear physics’ interdisciplinary progress

Nuclear physics’ interpretations could benefit from approaches found in other fields of physics.
© Christoph Burgstedt / Fotolia

Theoretical nuclear physics could yield unique insights by extending methods and observations from other research fields

The theoretical view of the structure of the atom nucleus is not carved in stone. Particularly, nuclear physics research could benefit from approaches found in other fields of physics. Reflections on these aspects were just released in a new type of rapid publications in the new Letters section of EPJ A, which provides a forum for the concise expression of more personal opinions on important scientific matters in the field. In a Letter to the EPJ A Editor, Pier Francesco Bortignon and Ricardo A. Broglia from the University of Milan, Italy, use, among others, the example of superconductivity to explain how nuclear physics can extend physical concepts originally developed in solid state physics.

Read more...

EPJ A Highlight - Analysing Coulomb-excitation experiments with exotic beams

Dedicated detection arrays for particle--ray coincidences are now routinely in use at radioactive-ion beam facilities around the world.

This paper presents a number of novel and alternative analysis techniques to extract transition strengths and quadrupole moments from Coulomb excitation data with Radioactive Ion Beams (RIBs) using the GOSIA code. It is anticipated that related approaches and techniques will gain an even greater importance as a wider range of post-accelerated RIBs becomes available at the next generation of ISOL facilities.

Read more...

EPJ A Highlight - First measurement of 60Ge β-decay

A sample image recorded by the OTPC detector’s CCD camera showing the particle trajectories. The vertical track corresponds to the 60Ge ion entering the detector and the other track corresponds to the (β-delayed) proton.

60Ge, with its 28 neutrons and 32 protons, is an extremely exotic nucleus, discovered about 10 years ago when only three ions were produced. Its decay properties were measured for the first time in this work. In this experiment, performed at the National Superconducting Cyclotron Laboratory (MSU, USA), the

60Ge ions were produced in 78Kr beam fragmentation reactions and separated from the other reaction products in the A1900 separator. The ions were detected in the active volume of the gaseous time-projection chamber with optical readout (OTPC), where they later decayed. This detector allows exotic decay modes to be identified, even with very small statistics present. The decay of about 20

60Ge ions was observed by β-delayed proton emission yielding a branching ratio of ~100% and a half-life of 20+7-5 ms. This value agrees well with theoretical predictions.

Read more...

EPJ A Review - Melting hadrons, boiling quarks

alt

In the context of the Hagedorn temperature half-centenary our understanding of the hot phases of hadronic matter both below and above the Hagedorn temperature is reviewed. The first part of this review paper just published in EPJ A addresses many frequently posed questions about properties of hadronic matter in different phases, phase transition and the exploration of quark-gluon plasma (QGP). The historical context of the discovery of QGP is described and the role of strangeness and strange antibaryon signature of QGP illustrated. In the second part the corresponding theoretical ideas and how experimental results can be used to describe the properties of QGP at hadronization are described.

Read more...

EPJ A Highlight - A new generation of chiral nuclear forces

Neutron-proton differential cross section at Elab=143 MeV up to fourth order in the chiral expansion.

Chiral effective field theory provides a systematically improvable perturbative approach to deriving nuclear forces in harmony with the symmetries of Quantum Chromodynamics. Combined with modern few- and many-body methods, this framework represents a commonly accepted procedure for ab initio studies of nuclear structure and reactions.

In this paper, the authors introduce a new generation of nucleon-nucleon forces up to fourth order in the chiral expansion. By employing an appropriate regularization in coordinate space, which maintains the analytic structure of the amplitude, the authors succeed in significantly reducing the amount of finite-cutoff artefacts. In addition, a simple approach to estimating the theoretical uncertainty in few- and many-nucleon calculations from the truncation of the chiral expansion is formulated. By calculating various two-nucleon scattering and bound-state observables, the authors verify that the results at different chiral orders and for different values of the regulator are indeed consistent with each other and with the experimental data.

The new generation of chiral nuclear forces is expected to provide an excellent starting point for applications in nuclear physics.

Read more...

Editor-in-Chief
A. Rubio

Executive Editors:
Eduardo Hernandez, Heiko Rieger, Bikas K. Chakrabarti, Wenhui Duan
I am naturally indebted to you and the referees who contributed to this success with your time and constructive advice.

Hamid Assadi

ISSN (Print Edition): 1434-6028
ISSN (Electronic Edition): 1434-6036

© EDP Sciences, Società Italiana di Fisica and Springer-Verlag

Conference announcements

POSMOL 2017

Magnetic Island, Queensland, Australia, 22-24 July 2017