BM@N

BM@N (Baryonic Matter at Nuclotron) is a fixed-target experiment operating at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. It is a key facility of the NICA megascience project, designed to study dense baryonic matter created in collisions of heavy ion beams with stationary nuclear targets. The experiment utilizes beams from the Nuclotron accelerator complex to investigate the properties of nuclear matter under extreme conditions.

Overview

The experiment was conceived as part of the broader NICA project to explore the phase diagram of nuclear matter. It serves as a precursor and complementary facility to the larger MPD experiment at the NICA collider. The primary focus is on investigating high-density baryonic matter, a state believed to have existed microseconds after the Big Bang and which may exist today in the cores of neutron stars. Research at the facility contributes to global efforts in relativistic heavy-ion physics, alongside major experiments like those at the Relativistic Heavy Ion Collider and the Large Hadron Collider.

Experimental setup

The detector is installed in the beamline of the Nuclotron, which provides ion beams from deuteron to gold-197 at energies up to several GeV per nucleon. The central apparatus is a spectrometer based on a large-aperture dipole magnet. Key detection systems include a set of silicon microstrip detectors for vertex reconstruction, gas electron multiplier-based tracking chambers, and time-of-flight detectors for particle identification. The setup also incorporates calorimeter systems for measuring neutral particles and multiwire proportional chambers for precise momentum analysis. The integration of these systems allows for comprehensive event reconstruction in collisions with fixed targets made of materials like lead, copper, and carbon.

Physics goals and research program

The core scientific mission is to study the equation of state of dense, strongly interacting matter and to search for signatures of a possible phase transition to a mixed phase or deconfined state. A major goal is the investigation of strangeness production and the properties of hyperons in dense nuclear environments, which are crucial for understanding neutron star interiors. The research program includes precise measurements of collective flow patterns, particle yield ratios, and dilepton production to probe the early, hot stages of collision fireballs. The experiment also aims to provide reference data for proton-nucleus collisions, which is essential for understanding the baseline effects of cold nuclear matter.

Key results and discoveries

Early runs have successfully recorded data from collisions of carbon and argon nuclei with various targets, establishing the performance of the detector systems. The collaboration has published first results on charged particle multiplicities and transverse momentum spectra, providing new input for models of nuclear interactions in the few-GeV energy range. Measurements of kaon and antikaon production are underway, offering insights into the restoration of chiral symmetry at high baryon densities. These findings contribute to the international data landscape explored by facilities like the HADES experiment at GSI Helmholtz Centre for Heavy Ion Research and the STAR experiment at Brookhaven National Laboratory.

Collaboration and participating institutions

The BM@N Collaboration is an international team of scientists from numerous institutes across Russia, Germany, Czech Republic, Slovakia, Poland, Bulgaria, Armenia, and Belarus. Major participating institutions include the Joint Institute for Nuclear Research as the host laboratory, the Institute for Nuclear Research of the Russian Academy of Sciences, and Goethe University Frankfurt. Other key contributors are the University of Tübingen, the Czech Technical University in Prague, and the Warsaw University of Technology. The collaboration works in close coordination with the broader NICA project community.

Category:Particle physics experiments Category:Joint Institute for Nuclear Research Category:Nuclear physics