Nuclear matter experts meet in Dresden

HZDR organizes international conference on the HADES project


This news is based on a news by Helmholtz-Zentrum Dresden-Rossendorf (HZDR).

From March 2 to 6, 2020, the 38th HADES Collaboration Meeting will take place at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) with more than 80 participants from more than 20 institutes in nine European countries. At the meeting, the scientists will discuss the status of the HADES detector system for the planned use at the international accelerator FAIR and a roadmap for future measurements.

The international accelerator center FAIR (Facility for Antiproton and Ion Research) is currently being built at GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt and is one of the largest research projects worldwide. Here, scientists from all over the world want to create matter in the laboratory that otherwise only occurs in the depth of space. They expect new insights into the structure of matter and the evolution of the universe from the Big Bang to the present.

One piece of the puzzle on the way and at the same time a major challenge for modern particle physics is to explain the origin of the masses of important components of matter. So-called hadrons (protons and neutrons) combine 99 percent of the mass of luminous matter in the universe. The same applies to our natural environment, in which protons and neutrons are largely bound in nuclei. To understand the phenomenon of the "mass of hadrons", scientists use different methods. One way is to study the decay products of particularly suitable hadrons in the environment of strongly interacting matter. These elementary particles, grouped together as vector mesons, are created in the collisions of heavy ions. However, scientists can also produce them in the laboratory by bombarding nuclei with elementary particles. Thus, nuclear physicists create strongly interacting matter with up to three times the nuclear density, at temperatures equivalent to 50,000 times the temperature inside the sun.

HADES: Know-how for precise hadron spectroscopy

The vector mesons produced in this way decay, among other things, into so-called lepton pairs, which are e. g. composed of electrons and positrons. But this is a relatively rare process. This is why the researchers need special detectors. This is where HADES (High Acceptance Di-Electron Spectrometer) comes in. The detector is installed at GSI and calibrated to those electron-positron pairs that leave the surrounding strongly interacting matter almost undisturbed, thus providing direct access to the original mass of their initial hadrons.

HADES was developed in an international collaboration at the heavy ion synchrotron SIS18 at GSI, which has now been running for 25 years. The lively cooperation of around 100 scientists has resulted in an intensive transfer of knowledge in the field of particle physics — from Monte Carlo simulations and detector construction to fast front-end electronics and data analysis — which also benefits HZDR and has already manifested in almost 250 scientific publications.

The HZDR is extensively involved in HADES: Alone 12 of the 24 drift chamber detectors were manufactured in the HZDR detector laboratory, now the multifunctional laboratory. They are the centerpiece, which allows the precise measurement of the momenta of charged reaction products from the heavy ion impact. The results enable investigations of the equation of state of hot dense matter, comparable to the state in neutron stars. In this way, researchers obtain an unaltered view of the interior of highly compressed nuclear matter. At their meeting, the experts want to discuss previous results and future measurements at the heavy ion synchrotron SIS18 at GSI in the framework of the "FAIR Phase 0" research program and at the FAIR ring accelerator SIS100. (HZDR/CP)

Further information:

News of HZDR (German)