Deutsches Elektronen-Synchrotron DESY
Notkestraße 85
22607 Hamburg


Humboldt Universität zu Berlin
Mathematisch-Naturwissen­schaft­liche Fakultät
Institut für Physik
Experimentelle Elementarteilchenphysik
Newtonstraße 15
10099 Berlin

The existence of an unknown, invisible component of the matter in our Universe, the Dark Matter, is by now well established by cosmological measurements. Dark Matter is five times more abundant than ordinary matter, yet its nature and interaction properties are still unknown. Its existence, however, implies that our understanding of the basic building blocks of the Universe is incomplete. Uncovering the identity of Dark Matter is therefore a central and grand challenge for both fundamental physics and astronomy of this century. In the highenergy proton-proton collisions at the Large Hadron Collider at CERN, particles that werepresent in the early universe can be recreated and studied in detail. The focus of the proposed Young Investigator Group (YIG), will be to search and study Dark Matter particles produced in the controlled environment of this big laboratory and recorded by the ATLAS experiment. The YIG, integrated in the DESY ATLAS group and in collaboration with
Humboldt University, will focus on the particularly interesting possibility that the interaction between ordinary matter and Dark Matter is mediated by new scalar particles that extend the Higgs sector. In these models, the Higgs boson partners act like a portal to a new Dark Sector, to which Dark Matter particles belong.
As the Higgs particle, these new mediators interact strongest with the heaviest particles, and therefore are characterized by enhanced interactions to heavy flavour quarks (top and bottom quarks). Thanks to the large dataset delivered by the LHC by 2023, we will have good sensitivity to these new Higgs partners up to masses of 300 GeV (more than twice the Higgs mass) and we will have the possibility of probing the Dark Matter nature using these models. The YIG will strengthen the ATLAS physics program in searches for Dark Matter in the heavy flavour sector, by focusing on three complementary channels which have the highest discovery potential and sensitivity to Dark Matter properties: Dark Matter with top pairs, b-quark jets or a single top quark. The optimization of the sensitivity for these discovery channels will require the improvement of our knowledge of the experimental backgrounds and reconstruction algorithms of the ATLAS detector. The YIG will address these criticalities by performing two additional auxiliary measurements. The first measurement aims to improve our knowledge on one of the dominant background processes for this search, single top production, through a differential cross section measurement. The second aims to improve the current calibrations for bottom quark identification algorithms through a novel method using Z-bosons as standard candles.
In case of a discovery, ten times more data will be required to fully investigate and understand the new particle and its properties. This amount of data will be collected during the High Luminosity LHC (HL-LHC) Run planned for 2026 and beyond. For this reason, the YIG will contribute also to the detector development for the ATLAS inner tracking system upgrade foreseen for the HL-LHC Run, in synergy with the DESY ATLAS involvement and expertise in Zeuthen and Hamburg. The project will be based on the characterization of temperature effects on the tracking detector performance that has a direct impact on the identification of bottom-quark jets, a fundamental ingredient for this research plan.

Leader of the Helmholtz Young Investigators Group:

Dr. Priscilla Pani
Deutsches Elektronen-Synchrotron DESY
Notkestr. 85
22607 Hamburg

Phone: +49 40 8998-0
Email: priscilla.pani@desy.de

Partner university:

Prof. Dr. Thomas Lohse
Humboldt Universität zu Berlin
Mathematisch-Naturwissen­schaft­liche Fakultät
Institut für Physik
Experimentelle Elementarteilchenphysik
Newtonstraße 15
10099 Berlin

Weiterführende Links:

Sachbericht 2018 (366KB)

 

Sachbericht 2019 (1.5 MB)