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Partikeldagarna 2025
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Scaniasalen (Chalmers Conference Centre)
Scaniasalen
Chalmers Conference Centre
Chalmersplatsen 1, 412 58 Göteborg
Description
Partikeldagarna is the annual meeting of the Particle- and Astroparticle Physics section of the Swedish Physical Society.
The aim of the meeting is to have a status report and a professional discussion on current particle and astroparticle physics research in Sweden. Please follow the menu on the left for further information.
Note that participation in Partikeldagarna is restricted to members of the Swedish Physical Society (master students are exempted from this restriction). Further information on membership can be found here.
The registration fee is 1375 SEK. (incl VAT)
The Conference dinner costs an additional 750 SEK (incl VAT).
See payment instructions link.
Partikeldagarna will feature two invited speakers covering hot topics in particle and astroparticle physics:
-- Dr. David Marzocca, INFN and SISSA, Trieste, Italy; "Theory overview of physics possibilities with high energy muon beams "
-- Prof. Julia Tjus, Ruhr U., Bochum, Germany; "Hadronic interactions - synergies in astro- and particle physics "
The event will also feature a discussion session with
-- Prof. Mattias Marklund, who will recount his previous experience as Secretary General for Natural Sciences at the Swedish Research Council.
-- Prof. Lisbeth Olsson, who is the current Secretary General for Research Infrastructure at the Swedish Research Council.
Registration deadline: 14/11/2025
Abstract submission deadline: 31/10/2025
Venue: Chalmers Conference Centre, Scaniasalen (Scania room), Chalmersplatsen 1, 412 58 Göteborg.
Local Organizing Committee:
Gabriele Ferretti, Riccardo Catena, Joanna Sobczyk
Swedish Physical Society Board and Organizing Committee:
C. Pérez de los Heros (UU, Chair), S. Choubey (KTH), G. Ferretti (CTH), C. Finley (SU), R. González Suárez (UU), D. Silvermyr (LU), M. Sjödahl (LU), J. Sjölin (SU)
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09:00
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09:30
Registration 30m
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09:30
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09:40
Introduction 10m
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09:40
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10:45
Monday morning session 1
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09:40
LDMX status and outlook 20m
The Light Dark Matter eXperiment (LDMX) is a ‘missing momentum’ experiment searching for dark matter in the MeV to GeV-equivalent mass range. LDMX plans to use a high-repetition, low-current 8 GeV electron beam along with a high-Z target to potentially produce DM through high-statistics electron-nucleus interactions. Using a sophisticated system of complementary taggers, trackers, and calorimeters, the events from the electron-beam interactions can be reconstructed and used to determine if the event topology is compatible with DM production. The missing momentum method is largely agnostic to DM production models, and the detailed event data available enables LDMX to extend its reach to other rare-event and Beyond the Standard Model searches.
In this talk, I will describe the LDMX baseline design, as well as recent developments in the construction of a prototype detector which is expected to begin testing by the end of 2025. I will also outline in brief the rich physics program available with the LDMX setup, as well as the event characterization and analysis strategy. I will highlight the contributions from the LDMX group at Lund University as well as discussing the roadmap for the near future.
Speaker: Clay Barton (Lund University) -
10:00
LDMX Readout Electronics ASIC Characterization 15m
The Light Dark Matter eXperiment (LDMX) is a fixed-target electron-beam experiment aimed at observing light dark matter (LDM) production through missing momentum. LDMX’s electronic and hadronic calorimeter uses the HGCROC ASIC from the CMS experiment for electronic readout. This work focuses on the characteristic behavior of the ASIC’s Analogue to Digital Converter (ADC). The linearity of ADC and Time Over Threshold (TOT) was studied with a series of controlled charge injections. The linearity of the ADC was investigated by tracking the behavior of the ADC pulse amplitude upon varying the injected charge. The ADC response to an 8pF (low-range) and a 500fF (high-range) capacitor portrayed linear behavior. A correction was applied to the high-range measurements to align with the obtained low-range values, allowing for better comparison of the injected charge along the circuit. The TOT, expressed as the time spanned by a plateau region produced as a result of saturation of the ADC, was expected to increase linearly with the amplitude of the pulse. This allows for the expansion of the linearity of the ADC in the saturated regime. The TOT threshold was correlated to an ADC value by identifying when 50% of the signals triggered the TOT readout.
Speakers: Andreas Pettersson (Lund University), Verena Hehl (Lund University) -
10:15
Light Dark Matter at Fixed-Target Experiments: Theories and Signatures 15m
Sub-GeV, or light, dark matter (DM) has emerged as a compelling candidate for the observed DM in the universe. Unlike the canonical WIMP, light DM can account for the thermal relic abundance while evading nuclear recoil direct detection constraints, due to its limited momentum transfer. This motivates alternative search strategies, such as electron recoil direct detection and accelerator based experiments.
Upcoming experiments such as the Light Dark Matter eXperiment (LDMX), are projected to probe a broad range of DM scenarios, significantly extending the sensitivity frontier for light DM theories.
In this talk, we highlight new types of dark sector theories and processes that can be probed at LDMX and complementary experiments, focusing on two examples: a vector DM candidate arising from a dark SU(2) gauge symmetry, and a dark photon model featuring higher-order electromagnetic moments.Speaker: Taylor Gray (Chalmers University of Technology) -
10:30
Solar dark photon absorption: Strategy for optimal material identification from Kramers-Kronig relations 15m
Dark photons are massive U(1) gauge bosons that interact with the Standard Model solely through kinetic mixing with standard photons. For sub-keV mass dark photons produced in the sun, absorption provides a possible detection channel. To maximize the detection probability, an optimal detector material needs to be identified. We develop a strategy to compare materials based on the calculation of material-independent upper limits on the absorption rate. Kramers-Kronig relations are used to derive separate upper limits for the longitudinal and transverse parts of the rate. A comparison of these limits with the expected rates for four example materials shows that 1) for dark photon masses close to the material’s plasma frequency the transverse part is the leading contribution to the rate and 2) for lower masses the longitudinal part dominates. These results can guide the selection of materials for detecting dark photons, potentially advancing detection capabilities.
Speaker: Theresa Magdalena Backes (Chalmers)
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09:40
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10:45
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11:15
Coffee break 30m
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11:15
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12:35
Monday morning session 2
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11:20
Recent results and new developments from the IceCube Neutrino Observatory 20m
The IceCube Neutrino Observatory in Antarctica is a versatile instrument in neutrino astronomy and particle physics. Over 5000 optical modules fill a volume of a cubic kilometer of ice. When a charged neutrino-secondary passes through the detector Cherenkov light is emitted that is picked up by the optical modules. Even exotic particles predicted beyond the Standard Model of particle physics can be searched for with IceCube if their interaction with the ice produces light.
With the observation of several astrophysical neutrino sources, IceCube also entered the field of multi-messenger physics, that has the potential to answer fundamental astrophysics questions.
This winter, the IceCube Upgrade will be constructed adding various new sensors densely packed in the center of IceCube in order to precisely measure neutrino oscillation parameters.
The sensors will additionally be used for ice calibration and tested aiming towards a future extension of the detector, called IceCube-Gen2.
In this talk, recent results and current developments from IceCube will be presented.Speaker: Anna Obertacke (Stockholm University) -
11:40
Long Lived Particles at the IceCube Neutrino Observatory 15m
This is the first-ever search for Long-Lived Particles (LLPs) produced by atmospheric muons at the IceCube Neutrino Observatory, a state-of-the-art neutrino telescope located 2 km below the South Pole ice. IceCube’s kilometer-scale detector, optimized for astrophysical neutrino detection, also provides an opportunity for particle physics searches for unique signatures in an unexplored energy regime.
Atmospheric muons, disregarded as background in most IceCube analyses, continuously reach the detector at a rate on the order of kilohertz. These muons could produce LLPs via an exotic muon–nucleus bremsstrahlung-like scattering. These LLPs would travel undetected for some distance and subsequently decay back into Standard Model particles, creating a distinct “dark gap”—a segment without Cherenkov light in the otherwise bright muon track. Identifying these rare signatures within the sparse detector geometry is a significant challenge, akin to finding a needle in a haystack, but provides a probe into new physics scenarios involving feebly interacting particles with long lifetimes.
This analysis, being the first of its kind, will complement collider-based searches by probing long decay lengths in a large, naturally thick detector medium, offering a novel window into feebly interacting new physics.Speaker: Axel Pontén (Uppsala University) -
11:55
Search for light dark matter with the XENONnT experiment 15m
The XENONnT experiment is the current iteration of liquid xenon detectors build and operated by the XENON collaboration. It is one of the leading experiments in providing limits on the WIMP-nucleon cross section for WIMPs heavier than 10 GeV/$c^2$. While primarily designed for the detection of more massive WIMPy dark matter, it is also sensitive to lower mass dark matter such as axions and hidden photons. This talk gives a summary of the latest results of the search for light dark matter with the XENONnT experiment.
Speaker: Torben Flehmke (su.se) -
12:10
Charm Contributions to Multi-Messenger Emissions in Dense AGN Environments 15m
Active galactic nuclei (AGN) are compelling sites for high-energy neutrino production, yet the balance between light-meson ($\pi, K$) and charm-hadron channels in dense, magnetised environments remains unresolved. We present a simulation-driven framework that couples a version of CRPropa designed for the AGN / jet environment and a Hadronic Interaction Module for $pp$ interactions with secondary tagging. Inclusive energy-differential cross sections $d \sigma / d x_E$ are computed and tabulated using chromo with Sibyll 2.3d, enabling consistent propagation from cosmic-ray injection to neutrino yields on finely sampled energy grids. By comparing decay, synchrotron, hadronic and adiabatic timescales, regimes are identified where $\pi/K$ channels can be suppressed while short-lived charm hadrons remain effectively prompt and could contribute to the neutrino signal significantly. The analysis points to coronae and dense jet substructures as potential "charm factories" within realistic acceleration limits. Validation of these qualitative indications using the framework through the spectral shape and flavour composition to isolate charm contributions is ongoing.
Speaker: Vladimir Kiselev (Ruhr University Bochum)
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11:20
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12:35
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13:45
Lunch 1h 10m
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13:45
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14:30
Plenary talk: Theory overview of physics possibilities with high energy muon beams. (David Marzocca) 45m
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14:30
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15:00
Discussion with Mattias Marklund, former VR Secretary General for Natural Sciences 30m
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15:00
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15:30
Coffee break 30m
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15:30
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16:00
Monday afternoon session 1
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15:30
Novel Spiral tuning technique for metamaterial based cavity for axion dark matter searches. 15m
The axion is a hypothetical pseudoscalar particle that arises from the Peccei-Quinn solution for the strong CP problem and simultaneously be a strong candidate for dark matter. Recent early-universe simulations for the post-inflation scenario have indicated a preference for a higher mass corresponding to above 10 GHz. This has motivated efforts to probe this high frequency regime that traditional cavity haloscope have a diminished sensitivity in, due to reduced resonant volume at these frequencies. The plasma haloscope offers a promising alternative to traditional haloscopes and consists of a periodic arrangement of conducting wires whose inter-wire spacing controls the frequency. Tuning the frequency requires changing the inter-wire spacing and can require mechanically complex structures to ensure simultaneous and consistent spacing of all the wires. In this talk I will present a novel tuning mechanism based on spiral geometry and show the simulation and experimental results as well as its potential implementation in the ALPHA experiment.
Speaker: Jacob Lindahl (Stockholm University) -
15:45
Prospects for finding light Z´-bosons in Coherent Elastic neutrino Nucleus Scattering at the ESS 15m
Coherent Elastic neutrino Nucleus Scattering at spallation sources such as the ESS, offer new exciting possibilities to also study physics beyond the standard model in a small scale experiment. There is an ongoing effort att Lund and Uppsala universities to explore these possibilities in more detail. As an example, I will describe the possibility to search for the X17 - a hypothetical light Z´-boson that, for example can explain observations in Be8* -> Be8 decays first observed by the ATOMKI experiment. I will present how the X17 would modify the nuclear recoil spectrum and discuss the prospects for confirming its existence in an experiment at the ESS using a germanium detector.
Work done in collaboration with Joakim Cederkäll, Yasar Hicyilmaz, Else Lytken, Stefano Moretti
Speaker: Johan Rathsman (Lund University)
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15:30
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16:00
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16:30
Discussion with Lisbeth Olsson, VR Secretary General for Research Infrastructure 30m
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16:30
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18:20
Monday afternoon session 2
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16:30
ESSnuSB overview 20mSpeaker: Dr Sampsa Vihonen (KTH Royal Institute of Technology)
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16:50
Classification of Electron and Muon Neutrino Events for the ESS𝝂SB Near Water Cherenkov Detector using Graph Neural Networks 15m
The European Spallation Source Neutrino Super Beam (ESSnuSB) is an experiment envisioned to make use of the world’s most intense proton source - produced at the European Spallation Source (ESS) - to create a powerful neutrino beam with the goal of studying Charge-Parity (CP) violation in the leptonic sector. This will allow the measuring of neutrinos in a Water Cherenkov (WC) detector in Zinkgruvan Mine in Sweden, to which the distance from ESS corresponds to the second neutrino oscillation maximum, where the effects of CP violation is greatest. Graph neural networks (GNNs) have proven well suited for Cherenkov detector event reconstruction, where the events are sparse, varying in size, and non-euclidian in structure. This work demonstrates the implementation of GNNs in the reconstruction of simulated ESSnuSB near detector events, and how GNNs can be used for fast investigations of variations in detector geometries and PMT properties in the developing stages of ESSnuSB.
Speaker: Kaare Iversen (lu.se) -
17:05
HIBEAM Project Status 20m
The HIBEAM experiment, the first stage of the HIBEAM–NNBAR program at the European Spallation Source (ESS), is a multidisciplinary effort designed to explore a wide range of fundamental physics questions. Its primary objectives include high-sensitivity searches for neutron oscillations, sterile neutrons, and axion-like particles, as well as investigations of exotic neutron decay channels.
In this talk, I will present an overview of the current status of the HIBEAM program—covering both technological and detector developments- and highlight how the physics scope has expanded well beyond neutron oscillation studies. The project continues to evolve into a broader effort addressing key open problems in particle physics, including matter–antimatter asymmetry, CP violation, and baryon number violation.
Speaker: Bernhard Meirose (chalmers.se) -
17:25
Accelerator Physics, a new section within the Swedish Physical Society 15m
A new section has been created in the Swedish Physical Society with high relevance also for Particle Physics, the section for Accelerator Physics. We will present the section with the aim of discussing and igniting future collaboration.
In Sweden we have a long tradition of research developing and operating accelerators. 100 years ago Gustav Ising put forward the ideas that later became the first linear accelerator. More than 80 years ago Olle Wernholm and Hannes Alfvén at Atomforskningsinstitutet in Stockholm worked with the development of a betatron followed by different microtrons. Research at Gustav Werner Institutet and later The Svedberg laboratoriet in Uppsala developed from the same period. This was followed with the Celsius ring in Uppsala, Cryring in Stockholm and Lucy in Lund. Mikael Eriksson started a new era with the three MAX accelerators (I, II and III) . In parallel Swedish research groups have been and are involved in numerous international projects depending on and using accelerators, from FAIR (with Cryring) and CERN to Myrrha, Dones and EuXFEL.
While the history involves many projects, current times have brought another boom for accelerators in Sweden. Key national facilities include Desiree in Stockholm, MAX IV and the international ESS in Lund. Laser particle acceleration is developed in Umeå, Gothenburg and Lund and we have the FREIA laboratory in Uppsala. Many large hospitals operate electron-beam accelerators and Skandionkliniken in Uppsala houses a proton accelerator. In parallel the industry has developed with companies such as Scandinova and Scanditronix a.o. In Europe FAIR is coming close to completion and the discussions about the FCC, or the LC, at CERN are intense.
There is now a critical mass in Sweden to gather for future development and exploration of Accelerator physics.
Speaker: Sverker Werin (lu.se) -
17:40
ALICE overview 20m
Overview of the Swedish ALICE activities.
Speaker: Peter Christiansen (lu.se) -
18:00
ALICE Upgrade Activities in Lund 15m
The current ALICE Inner Tracking System (ITS2) is based on Monolithic Active Pixel Sensors (MAPS) called ALPIDE. During LHC Long Shutdown 3, its three innermost layers will be replaced by the ITS3 detector.
The ALICE group at Lund participate in the testing of the first prototype ITS3 sensors, and developed the so-called DAQ-Raiser test system for laboratory and in-beam characterization of ITS3 sensors. The Lund group also developed the dedicated firmware and software interface. This contribution highlights the ALICE Upgrade activities in Lund and a report on the detector requirements, performance and future plans will be given.Speaker: Iaroslav Panasenko (lu.se)
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16:30
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19:30
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22:00
Conference dinner 2h 30m
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09:00
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09:30
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09:00
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10:35
Tuesday morning session
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09:00
Theoretical particle physics at Uppsala University 20m
I will give an overview of the research on physics beyond the Standard Model, collider physics, astroparticle/early universe physics and gravitational waves in the Theoretical Particle Physics group at Uppsala University.
Speaker: Rikard Enberg (Uppsala University) -
09:20
Finite-volume QED for precision physics 15m
Non-perturbative effects in precision calculations involving QCD at low energies must be handled with tools such as lattice and effective field theory. The achievable level of precision in many modern experiments demands that electromagnetic effects in addition to QCD be included in theoretical calculations. In lattice QCD where simulations are performed in non-physical Euclidean spacetimes of finite volume, this necessitates the introduction of dedicated finite-volume QED prescriptions. In this talk I will discuss different prescriptions, the complications arising in extracting physical information from lattice simulations and the impact for future precision tests in the search for new physics.
Speaker: Nils Hermansson-Truedsson (lu.se) -
09:35
3HDM Unveiled: From Theory to Smoking Gun Signals at Future Colliders 15m
In this talk, I will explore several aspects of the Three-Higgs Doublet Model (3HDM) and discuss the strong theoretical motivations that make it a compelling extension of the Standard Model (SM). The 3HDM not only offers intriguing possibilities to address some of the long-standing shortcomings of the SM but also provides unique phenomenological features. I will highlight a set of distinctive “smoking gun” signatures that could be probed at future collider experiments. These signals have the potential to serve as clear indicators of new physics, guiding us toward a deeper understanding of Beyond Standard Model (BSM) scenarios and shaping future searches in high-energy physics.
Speaker: Atri Dey (Postdoc, High Energy Physics, Uppsala University) -
09:50
Renormalizability and UV behavior of 5D gauge theories 15m
The idea of supplementing the number of spacetime dimensions has long been deemed as one of the potential extension of the Standard Model, as it provides powerful tools to explain some of its shortcomings. One example of higher-dimensional formulations are asymptotic grand unified theories (aGUTs), for which the couplings do not meet at a high scale, but instead flow together towards a fixed point in the UV. Although the higher-dimensional dynamics push the theories into a nonpertubatively renormalizable regime, they can be thought of as fundamental in the context of the asymptotic safety scenario. Using these techniques, we focus on five-dimensional gauge theories and check whether a good behavior in the UV is present or not, with the purpose of shedding light on the renormalization status of such models.
Speaker: Anca Preda (lu.se) -
10:05
Confronting the production mechanisms of nuclei at the LHC with deuteron and proton-triggered balance functions 15m
A hot topic at the Large Hadron Collider (LHC) is the production of anti-nuclei. In ultra high-energy collisions, nuclei with very low binding energies are not expected to survive the dense and hot final state environment. The traditional view of nuclei production has been that antinuclei form via coalescence after the hot environment has dissipated. However, statistical thermal models, where hadrons are produced from a fireball at thermal equilibrium, can also describe the relative abundances of light nuclei in pp and heavy-ion collisions at the LHC. Thus, in this talk, we investigate the deuteron and anti-deuteron production in relativistic hadronic collisions at the LHC to test the microscopic mechanism of their production, which is still under debate. We investigate whether balance functions, triggered by protons and deuterons, can provide a new way to distinguish between the two production scenarios. To this end, we employ PYTHIA to model the coalescence picture and the Thermal-FIST package to describe the thermal production framework.
Speaker: Dr Sushanta Tripathy (Lund University, Sweden) -
10:20
Deconstruction of resonant Higgs pair production cross section in the NMSSM 15m
We discuss the resonant production of Higgs pairs and its interference with the non-resonant di-Higgs production in the NMSSM. We deconstruct the differential cross section to different contributions arising from Standard Model box and triangle diagrams, resonant diagrams arising from heavy Higgs bosons, squark diagrams and the interferences between them. Interference lead to substantial modifications of the invariant mass spectrum, but also in the context of the NMSSM, the interference pattern gives information on how the Higgs boson gets its mass.
Speaker: Harri Waltari (Uppsala University)
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09:00
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10:35
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11:05
Coffee break 30m
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11:05
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12:35
Reports from groups
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11:05
News from IPPOG 15mSpeakers: Christian Ohm, Christian Ohm (KTH Royal Institute of Technology)
- 11:20
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11:35
News from APPEC 15m
APPEC, the AstroParticle Physics European Consortium, is just starting up it's work for the next decade's European roadmap for astroparticle physics, 2027-2036. This work was kicked off with a townhall meeting in Zaragoza, Spain, in September.
This talk will cover recent news from APPEC.
Speaker: Alexander Burgman (su.se) - 11:50
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- 12:20
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11:05
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12:35
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13:30
Lunch 55m
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13:30
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14:15
Plenary talk: Hadronic interactions - synergies in astro- and particle physics. (Julia Becker Tjus) 45m
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14:15
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14:45
Coffee break 30m
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14:45
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15:55
Tuesday afternoon session
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14:45
ATLAS summary 20m
Summary of ongoing projects in ATLAS Sweden
Speaker: Sten Åstrand (lu.se) -
15:05
Pythia in the Age of AI: Sweden's quiet Particle-Physics Infrastructure 20m
Every result in modern particle physics, from the Higgs discovery, searches for dark matter, and investigations of the quark–gluon plasma, depends on simulated collisions. As the world’s most widely used Monte Carlo event generator for particle physics, PYTHIA, developed and maintained in Lund, has been a quiet but globally indispensable Swedish contribution to high-energy physics for decades.
This talk will introduce what PYTHIA is and how it supports collider experiments. I will then discuss how PYTHIA is evolving for the next decade: adapting to upcoming, integrating with machine-learning workflows, and exploring differentiable and AI-assisted modelling. These developments are not just research curiosities but essential steps in maintaining a modern, sustainable simulation infrastructure for experiments with large Swedish involvement.
The talk will conclude with a look at how PYTHIA connects Swedish research to the global particle-physics ecosystem – and how the Swedish community can help shape its next chapter.
Speaker: Christian Bierlich (Lund University) -
15:25
JUNO’s Neutrino Mass Ordering Measurement Could be Impacted by Scalar Non-Standard Interactions 15m
The neutrino mass ordering (NMO) is one of the major contemporary questions in neutrino physics. Determining the NMO is the primary goal of the Jiangmen Underground Neutrino Observatory (JUNO), a recently operational next-generation reactor experiment. Furthermore, the advent of JUNO ushers in the precision era of neutrino oscillation physics. This enbales us, for the first time, to probe sub-leading effects on the oscillation spectrum. In this presentation we discuss how scalar-mediated non-standard interactions between neutrinos and matter would be seen in the JUNO experiment, and specifically how such interactions could impact JUNO's NMO determination.
Speaker: Andreas Lund (KTH Royal Institute of Technology) -
15:40
Finite-temperature bubble-nucleation with shifting scale hierarchies 15m
Focusing on supercooled PTs in models with classical scale symmetry, we investigate the limitations of derivative expansions in constructing a thermal EFT description for bubble nucleation. We show that derivative expansion for gauge field fluctuations diverges because the gauge field mass varies strongly between the high- and low-temperature phases. By computing the gauge fluctuation determinant, we show that these effects can be captured while accounting for large explicit logarithms at two loops. We show how this construction can improve nucleation rate calculations, providing a more robust framework for describing GW from supercooled PT in models like the SU(2)cSM.
Speaker: Maciej Kierkla (Uppsala University)
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14:45
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09:00
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10:35
