News / Highlights / Colloquium
- Published on Friday, 26 January 2018 17:10
How magnetic force acts on charged subatomic particles near the speed of light
Current textbooks often refer to the Lorentz-Maxwell force governed by the electric charge. But they rarely refer to the extension of that theory required to explain the magnetic force on a point particle. For elementary particles, such as muons or neutrinos, the magnetic force applied to such charges is unique and immutable. However, unlike the electric charge, the magnetic force strength is not quantised. For the magnetic force to act on them, the magnetic field has to be inhomogeneous. Hence this force is more difficult to understand in the context of particles whose speed is near the speed of light. Moreover, our understanding of how a point-particle carrying a charge moves in presence of an inhomogenous magnetic field relied until now on two theories that were believed to differ. The first stems from William Gilbert's study of elementary magnetism in 16th century, while the second relies on André-Marie Ampère electric currents. In a new study just published in EPJ C, the authors Johann Rafelski and colleagues from the University of Arizona, USA, succeeded in resolving this ambiguity between Ameperian and Gilbertian forms of magnetic force. Their solution makes it possible to characterise the interaction of particles whose speed is close to the speed of light in the presence of inhomogeneous electromagnetic fields.
EPJ C Highlight - Combining experimental data to test models of new physics that explain dark matter
- Published on Tuesday, 19 December 2017 17:32
The most statistically consistent and versatile tool to date is designed to gain insights into dark matter from models that extend the standard model of particle physics, rigorously comparing them with the latest experimental data
In chess, a gambit refers to a move in which a player risks one piece to gain an advantage. The quest to explain dark matter, a missing ingredient from the minimal model that can describe the fundamental particles we have observed (referred to as the standard model of particle physics), has left many physicists eager to gain an advantage when comparing theoretical models to as many experiments as possible. In particular, maintaining calculation speed without sacrificing the number of parameters involved is a priority. Now the GAMBIT collaboration, an international group of physicists, has just published a series of papers in EPJ C that offer the most promising approach to date to understanding dark matter.
- Published on Tuesday, 13 June 2017 10:03
The publishers of The European Physical Journal C – Particles and Fields are pleased to announce the appointment of Professor Dieter Zeppenfeld as new Editor-in-Chief for Theoretical Physics I: Phenomenology of the Standard Model and Beyond, replacing Professor Gino Isidori. Dieter Zeppenfeld is Head of the Institute for Theoretical Physics at the Karlsruher Institut für Technologie (KIT) and leads a research group on Collider Physics at KIT.
- Published on Friday, 22 July 2016 14:42
New theoretical models that better describe the interaction between dark matter and ordinary particles advance the quest for dark matter
In the quest for dark matter, physicists rely on particle colliders such as the LHC in CERN, located near Geneva, Switzerland. The trouble is: physicists still don't exactly know what dark matter is. Indeed, they can only see its effect in the form of gravity. Until now, theoretical physicists have used models based on a simple, abstract description of the interaction between dark matter and ordinary particles, such as the Effective Field Theories (EFTs). However, until we observe dark matter, it is impossible to know whether or not these models neglect some key signals. Now, the high energy physics community has come together to develop a set of simplified models, which retain the elegance of EFT-style models yet provide a better description of the signals of dark matter, at the LHC. These developments are described in a review published in EPJ C by Andrea De Simone and Thomas Jacques from the International School for Advanced Studies SISSA, in Trieste, Italy.
- Published on Tuesday, 12 July 2016 16:52
Theory to explain collective effects of neutrinos inside supernovae strengthened
Neutrinos are elementary particles known for displaying weak interactions. As a result, neutrinos passing each other in the same place hardly notice one another. Yet, neutrinos inside a supernova collectively behave differently because of their extremely high density. A new study reveals that neutrinos produced in the core of a supernova are highly localised compared to neutrinos from all other known sources. This result stems from a fresh estimate for an entity characterising these neutrinos, known as wave packets, which provide information on both their position and their momentum. These findings have just been published in EPJ C by Jörn Kersten from the University of Bergen, Norway, and his colleague Alexei Yu. Smirnov from the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. The study suggests that the wave packet size is irrelevant in simpler cases. This means that the standard theory for explaining neutrino behaviour, which does not rely on wavepackets, now enjoys a more sound theoretical foundation.
- Published on Tuesday, 22 March 2016 08:04
The publishers of The European Physical Journal C – Particles and Fields are pleased to announce the appointment of Professors Laura Baudis as new Editor-in-Chief. This follows the splitting of the experimental section into Experimental Physics I: Accelerator Based High-Energy Physics, now led by Jos Engelen, and Experimental Physics II: Astroparticle Physics, now led by Laura Baudis.
Laura Baudis is a Professor at the University of Zurich. Her research interests are in astroparticle physics and cosmology, in particular in the fields of direct dark matter detection and neutrino physics.
- Published on Wednesday, 27 January 2016 18:04
Highest sensitivity detector ever used for very light dark matter elementary particles
The origin of matter in the universe has puzzled physicists for generations. Today, we know that matter only accounts for 5% of our universe; another 25% is constituted of dark matter. And the remaining 70% is made up of dark energy. Dark matter itself represents an unsolved riddle.
Physicists believe that such dark matter is composed of (as yet undefined) elementary particles that stick together thanks to gravitational force. In a study recently published in EPJ C, scientists from the CRESST-II research project use the so-called phonon-light technique to detect dark matter. They are the first to use a detection probe that operates with such a low trigger threshold, which yields suitable sensitivity levels to uncover the as-yet elusive particles responsible for dark matter.
- Published on Tuesday, 13 January 2015 09:42
Study shows significant progress in determining what dark matter is not made of, thanks to much more sensitive detectors capable of identifying the presence of elusive particles, called WIMPs
According to astronomical observations, dark matter constitutes a five times greater proportion of the universe than ordinary matter, which only makes up 5% of the matter in the universe. The remaining 70% of the universe is known as dark energy. However, we still do not know what dark matter is made of. Indeed, none of the known elementary particles fulfil the criteria to explain dark matter. One theory suggests that it consists of as yet unknown elementary particles that interact only very weakly with ordinary matter, fittingly called WIMPs (Weakly Interacting Massive Particles). Now, members of the CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) collaboration have analysed recent data showing what dark matter is not made of, from a new kind of detector for such particles. This work has recently been published in EPJ C.
- Published on Wednesday, 01 January 2014 20:52
As of January 2014, The European Physical Journal C – Particles and Fields will be published as full open access journal funded by SCOAP3. One of the leading journals in the field, EPJ C was selected to participate in this initiative - lead by CERN with the support of partners in 24 countries - which will make a vast fraction of scientific articles in the field of High-Energy Physics open access at no cost for any author. Moreover authors will retain copyright and creative commons licenses will enable wide re-use of the published material.
- Published on Tuesday, 23 July 2013 13:37
Understanding complexity in the early universe may require combining simpler models to interpret cosmological observations
Complicated statistical behaviour observed in complex systems such as early universe can often be understood if it is broken down into simpler ones. Two physicists, Petr Jizba (currently affiliated with the Czech Technical University in Prague), and Fabio Scardigli (now working at Kyoto University in Japan), have just published results in EPJ C pertaining to theoretical predictions of such cosmological systems’ dynamics.