FAKT Workshop 2025: Particle Physics Retreat
This workshop serves as a platform to get to know the nuclear and particle physics community in Austria, to connect the participating institutes, to network, and to strengthen the existing collaborations.
The workshop takes place in the JUFA hotel in Bruck an der Mur: https://www.jufahotels.com/hotel/bruck-an-der-mur/
The meeting starts on Monday (Feb 10) at 10:30 and ends on Tuesday (Feb 11) after lunch.
For booking a room, please send an email to r.bruck@jufahotels.com with the subject "Zimmerreservierung 'Österreichische Akademie der Wissenschaften 10.2.-11.2." and provide name, address, and date of birth.
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Talks: Morning session
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1
WelcomeSpeaker: Florian Reindl (Vienna University of Technology (AT))
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3
Higgs physics at future collidersSpeaker: Georg Ralf Weiglein (Deutsches Elektronen-Synchrotron (DE))
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1
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12:10
Lunch
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Talks: Afternoon session
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5
European Strategy Update: DiscussionSpeaker: Simon Platzer (University of Graz (AT))
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16:00
Coffe break
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Talks: Afternoon session
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6
European Strategy Update: DiscussionSpeaker: Simon Platzer (University of Graz (AT))
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7
General FAKT discussionSpeaker: Florian Reindl (Vienna University of Technology (AT))
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6
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19:00
Dinner
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Talks - Tuesday: Morning 1
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8
Recent highlights from the CMS Experiment
In this talk, I will review recent highlights from the CMS experiment, including results from the HEPHY CMS Data Analysis group.
Speaker: Robert Schoefbeck (Austrian Academy of Sciences (AT)) -
9
ALICE 3: A next generation heavy-ion detector
The 'ALICE 3' project is a proposed upgrade of the ALICE detector, which involves a complete replacement of the installation at Point 2 to fully utilize the high-luminosity LHC. Crucial to the physics programme are high-precision measurements of heavy-flavour observables that require large data samples as well as state-of-the-art tracking performance. As a consequence, performance studies of the operating conditions of ALICE 3 that employ full simulation chains are very computationally demanding, especially in what concerns particle transport and detector response simulation. In this context, finding alternative representations of certain steps of full simulations is extremely useful. Such techniques are called `fast simulations' and reduce computing requirements by at least one order of magnitude.
This contribution provides an overview of the ALICE 3 upgrade, highlighting the current status and development of fast simulations for the ALICE 3 detector. Ongoing studies that explore various tracker configurations and particle identification setups will be discussed. We will also elaborate on how current fast simulations make efficient use of resources by running entirely in physical memory and not storing anything except for the desired physics performance quantities. Lastly, we will discuss the performance study of multi-charm baryons, which is not computationally feasible with full simulations alone, as a test case of the fast simulation machinery.
Speaker: Jesper Karlsson Gumprecht (Austrian Academy of Sciences (AT)) -
10
Overview of TU Wien Activities at the MedAustron Accelerator Facility
This presentation provides an overview of TU Wien's research activities at the MedAustron synchrotron in the fields of accelerator and medical physics, using the for research available 60-800 MeV proton, 120-400 MeV/u carbon and 40-400 MeV/u helium ion beams.
These activities include, among others, the delivery of novel ion beam modalities, such as ultra-low flux and mixed helium-carbon ion beams, as well as their applications, for example, in advanced imaging techniques like ion computed tomography.
The main emphasis of the talk will be the ongoing investigation into the delivery of mixed helium and carbon ion beams at the MedAustron accelerator facility. Due to their different ranges after simultaneous acceleration, the carbon ions are used to irradiate the tumor, whereas the helium ions could potentially be exploited for online range verification in a detector system downstream of the patient in the form of a helium radiography.Speaker: Matthias Kausel (MedAustron, TU Wien) -
11
The n_TOF experiment - neutrons for nuclear technology, medicine & fundamental research
The pulsed broad-range neutron time-of-flight facility n_TOF at CERN is a world-leading research facility for studying neutron-induced reactions. The CERN accelerator complex’ high intensity short proton pulses impinge on a a massive gas cooled lead spallation target. The resulting high instantaneous intensity neutron pulses arrive at two experiment stations EAR1 and EAR2, at 185 m and 19 m respectively, operating in parallel together with the recently developed activation station NEAR roughly 2 meters from the spallation target. The instantaneous intensity allows the measurement with low mass and highly radioactive samples, not possible elsewhere. The use of a light water moderator yields a wide neutron energy range of more than eleven decades from meV to GeV without overlap from pulses.
The n_TOF collaboration, bringing together 140 researchers of 40 institutes from all over the world, is the world’s largest community dedicated to measuring neutron induced cross sections. Over the course of two decades, more than one hundred experiments have been performed by the n_TOF Collaboration, in the domain of nuclear data for advanced technologies (neutron capture, neutron induced fission and (n,cp) reactions for accelerator driven systems, Gen-IV and Th/U fuel cycle), in nuclear astrophysics (heavy elements synthesis in stars, big bang nucleosynthesis, nuclear cosmo-chronology), and for fundamental nuclear science (nuclear structure and decay of highly excited compound states). Future plans for n_TOF include the development of detectors for reaction channels complementing neutron-induced capture, fission and light charged-particle reactions. This involves in particular the (n,xn) reaction channel and activation measurements at NEAR.
A brief overview of the facility and highlights of the experimental activities performed at n_TOF will be presented, with a particular emphasis on the Austrian contribution to the experimental programme, highlighting developments in the (n,xn) reaction channel.
Speaker: Michael Bacak (Vienna University of Technology (AT)) -
12
Silicon Carbide Detectors for Future Colliders and Medical Applications
Silicon carbide (SiC), a wide bandgap semiconductor, has many excellent material properties that make it an attractive candidate for particle detectors. Thanks to widespread usage in the power electronics industry, SiC processing has undergone significant quality improvements in the last ten years, with a reduction in price and an increase in wafer sizes. At the same time, particle physics experiments at colliders have increased their radiation hardness requirements, now demanding detectors to perform up to fluences of $10^{17} \mathrm{n}_{\mathrm{eq.}}/\mathrm{cm}^2$. For silicon detectors, the leakage current increases and charge collection efficiency decreases rapidly above $10^{15} \mathrm{n}_{\mathrm{eq.}}/\mathrm{cm}^2$, resulting in a large power draw that needs to be cooled. This has re-catalyzed the search for alternative semiconductor materials. Diamond detectors have been investigated with promising results, but the cost of the material prohibits large-scale ($> 1 \mathrm{m^2}$) applications. Silicon carbide combines the advantageous material properties of wide band gap semiconductors with the processing technology and low cost of silicon.
We present the current status of R&D at HEPHY towards radiation-hard SiC timing detectors for future colliders and medical applications. We investigated the radiation hardness of SiC as a material and found a negligible increase of the leakage current for fluences up to $10^{18} \mathrm{n}_{\mathrm{eq.}}/\mathrm{cm}^2$, allowing for room-temperature operation after irradiation.
To leverage the fast charge carrier velocities, we are developing SiC low-gain avalanche diodes (SiC-LGADs) that could surpass the timing performance of silicon LGADs in the future, mitigating the increased pileup at increased luminosities.In addition to HEP applications, we also develop SiC detectors for clinical applications.
Two applications will be presented: First, we have developed time-resolved SiC dosimeters for ultra-high dose rate ion beams at MedAustron. High dose rates ($>$40 Gy/s) allow the FLASH effect to be leveraged, widening the treatment window and improving patient outcomes. Second, we are developing next-generation SiC microdosimeters, which not only measure the dose but the radiation quality as well, which can be used to quantify the biological impact of the delivered dose.Speaker: Andreas Gsponer (Austrian Academy of Sciences (AT)) -
13
COSINUS and CRESST updates
COSINUS (Cryogenic Observatory for SIgnatures seen in Next-generation Underground Searches) and CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) are experiments conducted at the LNGS (Laboratori Nazionali del Gran Sasso) in Italy. Both search for dark matter (DM) nucleus scattering, and their key technology is a combination of 1) using transition edge sensors (TESs) on scintillating crystals at millikelvin temperatures to measure tiny phonon signals caused by particle interactions, and 2) additionally capturing the scintillation light. This dual-channel readout makes effective discrimination of electromagnetic backgrounds possible.
While CRESST is the leading experiment in exploring sub-GeV mass DM, with the constant goal of lowering the energy threshold, COSINUS will answer the long-standing question of whether the signal recorded by the DAMA/LIBRA collaboration could have a DM origin. To achieve this, COSINUS employs ultrapure NaI crystals operated as cryogenic scintillating calorimeters, which renders it unique among NaI-based experiments and allows a cross-check that is inherently model-independent.
This talk will give updates on the latest results, ongoing efforts, as well as perspectives for the future.Speaker: Philipp Schreiner (Vienna University of Technology (AT))
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8
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10:45
Coffe break
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Talks - Tuesday: Morning 2
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14
Particle physics at the University of Graz
I will give a brief overview of the research activities currently going on in the field of particle physics at the University of Graz.
Speaker: Michael Mandl (University of Graz) -
15
Ongoing research at the University of Vienna
I will provide a concise overview of the current research being conducted by the particle physics group at the University of Vienna.
Speaker: Prof. Massimiliano Procura (University of Vienna) -
16
Machine learning in lattice QCD and beyond
I will give an overview of our group’s progress in applying machine learning to lattice QCD, including the design of gauge-equivariant neural network layers that can learn a fixed-point action. I will also share our ongoing work on diffusion models and ideas for collaborative efforts towards large physics models.
I would like to take this chance to promote the European Coalition for AI in Fundamental Physics (EuCAIF) and its role in the upcoming JENA white paper on European Federated Computing.
Speaker: Andreas Ipp (TU Wien) -
17
Tensor mesons in holographic QCD and their contribution to the muon g-2
The hadronic light-by-light contribution to the muon $g-2$ contains contributions from intermediate massive spin 2 particles, i.e. tensor mesons.
We use holographic models of QCD (hQCD) to calculate masses, decay constants and transition form factors (TFFs) of tensor mesons and compare them to experimental data. These tensor meson TFFs may be decomposed into 5 Lorentz structures $T_i^{\mu \nu \alpha \beta}$ and structure functions $\mathcal{F}_i$. Compared to previous phenomenological analyses (with the so called quark-model) which only use $\mathcal{F}_1$, a second structure function $\mathcal{F}_3$ appears in hQCD due to 5-dimensional covariance.
In the comparison to the (singly-virtual) helicity data from BELLE of the $f_2(1270)$ the hQCD model fares much better than the quark-model.
The pole contribution to the $g-2$ of $2.40 \times 10^{-11}$ is of the same magnitude as in the quark-model, but due to the additional structure function $\mathcal{F}_3$ (which only plays a role in doubly virtual observables) is of the opposite sign.This puts into question some proposed error bands for tensor contributions in the literature and calls for more sophisticated phenomenological models including $\mathcal{F}_3$.
We also present full pole+non-pole evaluations in hQCD which go beyond the dispersive formalism and allow for a summation over infinitely many tensor mesons. In this full evaluation additional "trace terms" appear in the tensor-$\gamma \gamma$ vertex which disappear in the dispersive approach since they only contribute off-shell.Surprisingly the holographic tensor meson tower contributes to the symmetric longitudinal short distance constraint (SDC), but not to the Melnikov-Vainshtein constraint. The total contribution of axials and tensors now comes remarkably close to fulfilling the symmetric SCD exactly, further strenghening hQCD models.
Speaker: Jonas Mager (TU Wien) -
18
Conclusions not yet drawn from the unsolved 4/3-problem.\\ How to get a stable classical electron.
It has been known for over 100 years that there is a discrepancy between Maxwell's electrodynamics and the idea of a classical electron as the ``atom'' of electricity. This incompatibility is known under the terms 4/3 problem of the classical electron and radiation reaction force and was circumvented in the currently most successful theories, the quantum field theories, by limit value considerations, by the mutual subtraction of infinities, i.e. by purely mathematical methods that eliminate obvious contradictions, but are not really based on an intuitive understanding and can therefore never really be understood by the physically interested public. The actual cause of the problems mentioned lies in the instability of the classical electron. Stabilization cannot be achieved within the framework of Maxwell's electrodynamics. This raises the question of what a minimal change to the fundamentals of electrodynamics should look like, which Maxwell's theory contains as a limiting case. A detailed analysis of the 4/3 problem points to models that fulfill these requirements.
Speaker: Manfried Faber
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14
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13:00
Lunch
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