Press Releases by the University or the Department

At present, the radioisotope thorium-229 is considered to be the only candidate for use in a nuclear clock. A nuclear clock of this kind would be considerably more accurate than the current atomic clocks. The timekeeper in this case would be the rate of oscillations in the nucleus of thorium-229, induced by laser light excitations. Researchers have now developed a new method to determine the excitation energy with significantly more precision. The corresponding experiments were undertaken by an international team headed by researchers from KU Leuven. German members of the team came from Johannes Gutenberg University Mainz (JGU), LMU Munich, the Helmholtz Institute Mainz (HIM) and the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt. The researchers have recently published their results in Nature. ...

Vom 8. bis 12. Mai treffen sich mehr als 70 theoretische Physikerinnen und Physiker in Mainz zu einer ganz besonderen Veranstaltung – beim Jubiläumssymposium des Mainzer Instituts für Theoretische Physik (MITP) loten sie die Grenzen ihres Faches aus, berichten über neueste Fortschritte in zahlreichen Forschungsfeldern und feiern zugleich den 10. Geburtstag des MITP. Eröffnet wird das Jubiläumssymposium durch den rheinland-pfälzischen Wissenschaftsminister Clemens Hoch und den Präsidenten der Johannes Gutenberg-Universität Mainz (JGU), Prof. Dr. Georg Krausch.

Wie gelingt es, angesichts der zahlreichen Forschungsrichtungen und Publikationen in den verschiedenen Bereichen der theoretischen Physik alle wichtigen Entwicklungen zu verfolgen und bei allen zukunftsweisenden Themen am Ball zu bleiben? Die Mainzer Antwort hierauf lautet kurz: MITP. Denn als Zentrum für theoretische Physik hat das MITP genau dies zum Ziel. Es fördert die internationale Vernetzung und Zusammenarbeit verschiedener Forschungsbereiche auf dem Gebiet der theoretischen Physik und bietet mit einem modernen Gäste- und Seminarzentrum Physikerinnen und Physikern aus aller Welt die Möglichkeit, in Mainz auf Zeit gemeinsam und interdisziplinär zu forschen. ...

At the Mainz electron accelerator MAMI, the A1 Collaboration, in connection with the dissertation work of Dr. Simon Kegel, has systematically measured the excitation of an α particle ‒ the nucleus of a 4He atom ‒ from its ground state to its first excited state with unprecedented accuracy. Comparing the experimental results and recent calculations using the corresponding low-energy theory, it becomes evident that the excitation of α particles is not correctly described based on the current understanding of nuclear forces ‒ and this raises a wealth of challenging questions. The related scientific article has been published as an Editors' suggestion in the eminent journal Physical Review Letters.

From the theoretical side, too, it is planned to shed light on this low-energy puzzle for the nuclear forces. Thus, the calculations of the transition form factor performed in the group of Professor Sonia Bacca, also from the Johannes Gutenberg University Mainz (JGU), are to be systematically improved and studied in detail in the framework of chiral effective field theory. ...

Professor Matthias Neubert of Johannes Gutenberg University Mainz (JGU) has been awarded a grant of nearly EUR 2.5 million by the European Research Council (ERC) for research in the field of theoretical elementary particle physics. In his proposed EFT4jets project, he wants to focus on the theoretical description of so-called jet processes based on effective field theories. This should make it possible for the first time to describe subtle quantum effects that have so far eluded quantitative theoretical description. A deeper understanding of these processes will be essential for discovering clues of new physics beyond the Standard Model of particle physics in the accelerator experiments at CERN's Large Hadron Collider (LHC). The ERC Advanced Grant is the EU's most highly endowed funding measure for individuals, awarded by the European Research Council to outstanding researchers from all disciplines. It is already the second award of this kind for Matthias Neubert. ...

The W boson is an elementary particle discovered at CERN in 1983 that is responsible for mediating the so-called weak interaction. The determination of its mass is of particular importance, for example as a precise test of the validity of the Standard Model of particle physics. After a first determination and publication of the mass in 2017, the ATLAS collaboration has now presented a new result for this mass. The preliminary result was presented by Prof. Matthias Schott, experimental physicist at the PRISMA+ Cluster of Excellence of Johannes Gutenberg University Mainz (JGU) at the "57th Rencontres de Moriond", one of the most important conferences for particle physics.

As a result, the mass of the W boson is 80,360 million electronvolts (MeV) with an uncertainty of 16 MeV. It is based on a reanalysis of 14 million W boson candidates recorded back in 2011 in proton-proton collisions at CERN's Large Hadron Collider (LHC). It is consistent with the expectation of the standard model of particle physics, directly contradicting the recent measurement of the CDF experiment at the Tevatron, which caused a major stir in the spring of 2022. ...

On behalf of the XENON collaboration, PhD student Daniel Wenz from the group of Professor Uwe Oberlack at the PRISMA+ Cluster of Excellence of Johannes Gutenberg University Mainz (JGU) presented results from XENONnT, the latest-generation experiment of the XENON Dark Matter project dedicated to the direct search for dark Matter in the form of Weakly Interacting Massive Particles (WIMPs). With an initial exposure slightly larger than one tonne x year, a blind analysis shows that the data is consistent with the expectations from the background-only hypothesis. XENONnT thus sets new limits on interaction of WIMPs with ordinary matter. Thanks to the five times lower background, XENONnT improved on the results from the former XENON1T experiment obtained with a similar exposure. An article has been submitted to Physical Review Letters. ...

An international research team with participation from Johannes Gutenberg University Mainz (JGU) has for the first time detected neutrinos created by a particle collider at very high energies. For this purpose, the researchers evaluated measurements from the new experiment FASER, which took data for the first time in 2022 at CERN with the start of the third run of the Large Hadron Collider (LHC). The results were presented at the 57th Rencontres de Moriond conference.

Neutrinos are ubiquitous elementary particles that are produced, among other things, during fusion processes in the sun or radioactive decays in nuclear reactors. They were first discovered in 1956. "Neutrinos are the weakest interacting elementary particles. Billions of them pass through our bodies every second without us noticing. That is why neutrinos are also called ghost particles," explained Professor Matthias Schott, experimental physicist at the PRISMA+ Cluster of Excellence at Mainz University. "Neutrinos are also produced billions of times during particle collisions in accelerators, where you have two beams of particles smashing together at extremely high energy. But until now we have never been able to detect them. We have now succeeded in doing so for the first time with FASER. From these experiments, we hope to gain further insight into the nature of these mysterious particles, especially in terms of their mass – a great mystery of modern physics," said Schott. ...

How does the world look like at the smallest scales? This is a question scientists are trying to answer in particle collider experiments like the Large Hadron Collider (LHC) at CERN in Switzerland. To compare the results of these experiments, theoretical physicists need to provide more and more precise predictions based on our current model for the interactions of fundamental particles, the so-called standard model. A key ingredient in these predictions are so called Feynman integrals. Recently, a team of the PRISMA+ Cluster of Excellence at Johannes Gutenberg University Mainz (JGU), consisting of Dr. Sebastian Pögel, Dr. Xing Wang and Prof. Dr. Stefan Weinzierl, developed a method to efficiently compute a new class of these Feynman integrals, associated to Calabi-Yau geometries. This research is now published in the renowned Physical Review Letters and opens the path to high-precision theoretical predictions of particle interactions and to a better understanding of the elegant mathematical structure underpinning the world of particle physics. ...

Im Oktober 2021 hat die Gemeinsame Wissenschaftskonferenz von Bund und Ländern die Aufnahme des Konsortiums NHR Süd-West – bestehend aus der Johannes Gutenberg-Universität Mainz (JGU), der Rheinland-Pfälzischen Technischen Universität Kaiserslautern-Landau, der Goethe-Universität Frankfurt und der Universität des Saarlandes – in den Verbund des Nationalen Hochleistungsrechnens (NHR) beschlossen. Mit der heutigen Einweihung des neuen Hochleistungsrechners MOGON NHR Süd-West an der JGU hat der Verbund einen weiteren wichtigen Schritt beim Aufbau einer modernen und leistungsstarken Forschungsinfrastruktur für das Nationale Hochleistungsrechnen gemacht. Die Beschaffung des neuen Hochleistungsrechners wurde mit 7,5 Millionen Euro aus der Bund-Länder-Förderung "Nationales Hochleistungsrechnen" finanziert, wovon 3,75 Millionen Euro durch das Land Rheinland-Pfalz bereitgestellt wurden. ...

Mit einem zweitägigen Workshop, zugleich ein Kick-off Meeting, haben die Universitäten Mainz und Würzburg die deutsche Beteiligung am NASA-Satelliten COSI vorbereitet. Aus Mainz ist die Gruppe von Prof. Dr. Uwe Oberlack vom Exzellenzcluster PRISMA+ beteiligt, aus Würzburg die Gruppe um den Astrophysiker Dr. Thomas Siegert. Das Gammastrahlenteleskop mit dem Namen Compton Spectrometer and Imager (COSI) wird die jüngste Geschichte der Sternentstehung, von Sternexplosionen und der Bildung chemischer Elemente in der Milchstraße untersuchen, die für die Entstehung der Erde selbst entscheidend waren. Es wird vom Space Sciences Laboratory der University of California Berkeley geleitet und soll 2027 als neueste "kleine Astrophysik-Mission" (Small Explorer) der NASA starten. Im Oktober 2021 hatte die NASA COSI aus 18 eingereichten Vorschlägen als neues Weltraumteleskop ausgewählt. ...

Dark matter remains one of the greatest mysteries of modern physics. It is clear that it must exist, because without dark matter, for example, the motion of galaxies cannot be explained. But it has never been possible to detect dark matter directly in an experiment. Currently, there are many proposals for new experiments: They aim to detect dark matter directly via its scattering from the constituents of the atomic nuclei of a detection medium, i.e., protons and neutrons.

A team of authors including Gilly Elor, a postdoctoral researcher at the PRISMA+ Cluster of Excellence at Johannes Gutenberg University Mainz (JGU), and Robert McGehee and Aaron Pierce of the University of Michigan in Ann Arbor in the USA has now proposed a new candidate for dark matter named HYPER, short for HighlY Interactive ParticlE Relics. The twist: In the HYPER model, some time after the formation of dark matter in the early universe, the strength of its interaction with normal matter increases abruptly – which on the one hand makes it potentially detectable today and at the same time can explain the abundance of dark matter. The researchers now present the HYPER Dark Matter model and the phase transition it contains for the first time in the current issue of the prestigious journal Physical Review Letters. ...