arXiv subjects

Alexander Burgman

Publications and source records attributed to Alexander Burgman.

6 recordsLinked to original sources

arXiv2026

Vertex reconstruction for a search for neutron-antineutron conversions with HIBEAM

The HIBEAM/NNBAR programme (incorporated into the FINESSE/NNBAR programme) at the European Spallation Source is proposed to search for neutrons converting to antineutrons. An important observable is the reconstructed vertex arising from charged particles produced by an antineutron annihilating on a thin target foil and which pass through a time projection chamber. This paper studies track clustering and foil-plane vertex reconstruction for this topology. Both non-machine-learning methods and graph-neural-network methods are tested and compared with each other, including deterministic clustering, trackless projection and a hybrid clustering/graph-neural-network chain with track classification and vertex refinement. We conclude that, for the geometrically simple events in the HIBEAM TPC, classical reconstruction methods perform on-par with machine-learning based methods in terms of vertex coordinate reconstruction. Custom machine-learning based methods can, however, deliver event-shape information that may be important in downstream analyses.

hep-ex↗

arXiv2025

Advancements in Computing and Simulation Techniques for the HIBEAM-NNBAR Experiment

The HIBEAM-NNBAR program is a proposed two-stage experiment at the European Spallation Source focusing on searches for baryon number violation processes as well as ultralight dark matter. This paper presents recent advancements in computing and simulation, including machine learning for event selection, fast parametric simulations for detector studies, and detailed modeling of the time projection chamber and readout electronics.

physics.ins-det↗

arXiv2025

Early Career Researcher Input to the European Strategy for Particle Physics Update: White Paper

This document, written by early career researchers (ECRs) in particle physics, aims to represent the perspectives of the European ECR community and serves as input for the 2025--2026 update of the European Strategy for Particle Physics. With input from a community-wide survey, it highlights key challenges faced by ECRs -- career stability, funding access and long-term research opportunities -- while proposing policy recommendations and targeted initiatives. It underscores the importance of practices fostering diverse, equitable, inclusive and healthy workplaces, as well as of stronger ECR communities, and highlights how effective communication and interdisciplinary collaborations reinforce the societal relevance of particle physics and promote continued support for large-scale and long-term projects. Finally, the future of both collider and beyond-collider experiments is addressed, emphasising the critical role of ECRs in shaping future projects. The ECR contribution is formed of two parts: the ten-page executive summary submitted as input to the European Strategy for Particle Physics Update and, as backup document, this extended white paper providing additional context.

hep-ex↗

arXiv2024

The HIBEAM Experiment

The violation of baryon number is an essential ingredient for baryogenesis - the preferential creation of matter over antimatter - needed to account for the observed baryon asymmetry in the Universe. However, such a process has yet to be experimentally observed. The HIBEAM/NNBAR program is a proposed two-stage experiment at the European Spallation Source to search for baryon number violation. The program will include high-sensitivity searches for processes that violate baryon number by one or two units: free neutron-antineutron oscillation via mixing, neutron-antineutron oscillation via regeneration from a sterile neutron state and neutron disappearance; the effective process of neutron regeneration is also possible. The program can be used to discover and characterize mixing in the neutron, antineutron and sterile neutron sectors. The experiment addresses topical open questions such as the origins of baryogenesis and the nature of dark matter, and is sensitive to scales of new physics substantially in excess of those available at colliders. A goal of the program is to open a discovery window to neutron conversion probabilities (sensitivities) by up to three orders of magnitude compared with previous searches, which is a rare opportunity. A conceptual design report for NNBAR has recently been published.

hep-ex↗

arXiv2021

The ESS neutrino super-beam near detector

The ESS Neutrino Super-Beam (ESSnuSB) is a proposed long-baseline neutrino oscillation experiment, performed with a high-intensity neutrino beam, to be developed as an extension to the European Spallation Source proton linac currently under construction in Lund, Sweden. The neutrinos would be detected with the near and far detectors of the experiment, the former within several hundred meters of the neutrino production point and the latter within several hundred kilometers. The far detector will consist of a megaton-scale water-Cherenkov detector, and the near detector will consist of a kiloton-scale water-Cherenkov detector in combination with a fine-grained tracking detector and an emulsion detector. The purpose of the near detector is to constrain the flux of the neutrino beam as well as to extract the electron-neutrino interaction cross-section in water, which requires high-performance energy reconstruction and particle flavor identification techniques. These measurements are crucial for the neutrino oscillation measurements that will be conducted using the far detector. Year 2021 sees the finalization of the conceptual design of the near detector after a thorough evaluation of the performance of a number of different design options, and a characterization of the neutrino reconstruction and flavor identification performances. In this talk we report on thesestudies.

hep-ex↗

arXiv2016

The opportunity offered by the ESSnuSB project to exploit the larger leptonic CP violation signal at the second oscillation maximum and the requirements of this project on the ESS accelerator complex

Very intense neutrino beams and large neutrino detectors will be needed to enable the discovery of CP violation in the leptonic sector. The European Spallation Source (ESS), currently under construction in Lund, Sweden, is a research center that will provide, by 2023, the world's most powerful neutron source. The average power will be 5 MW. Pulsing this linac at higher frequency, at the same instantaneous power, will make it possible to raise the average beam power to 10 MW to produce, in parallel with the spallation neutron production, a high performance neutrino Super Beam of about 0.4 GeV mean neutrino energy. The ESS neutrino Super Beam, ESSnuSB, operated with a 2.0 GeV linac proton beam, together with a large underground Water Cherenkov detector located at 540 km from Lund, close to the second oscillation maximum, will make it possible to discover leptonic CP violation at 5 sigma significance level in 56 percent (65 percent for an upgrade to 2.5 GeV beam energy) of the leptonic Dirac CP-violating phase range after 10 years of data taking. The paper gives an overview of the proposed facility and presents the outstanding physics reach possible for CP violation with ESSnuSB.

physics.ins-det↗