Astroparticle School 2023

4 Oct 2023, 09:00 → 12 Oct 2023, 21:00 Europe/Berlin

Obertrubach-Bärnfels

Uli Katz (ECAP / FAU Erlangen-Nürnberg), Claudio Kopper (FAU Erlangen), Sebastian Fiedlschuster (ECAP), Andreas Zmija (ECAP), Lisa Schumacher (Erlangen Centre for Astroparticle Physics (ECAP)), Christian Haack (ECAP, FAU Erlangen)

This year's edition will be held from 4 to 12 October 2023.

As in previous years, it will be hosted by the "Gasthof Drei Linden" in Obertrubach-Bärnfels, a small village in the countryside near Erlangen.

The School imparts broad knowledge through dedicated lectures and presents scientific highlights in presentations of 90 minutes.

Furthermore, the participants will present and discuss their own work in afternoon talks.

Accomodation at the conference venue is included in participation of the event. You will find detailed information about the School, accommodation, and the programme in the Bulletins. (You can also find this information using the various entries in the menu on the left of this page.)

Please note: registration for this year is already closed.

 

Supported by

              

 

Bulletin1.pdf

Bulletin2.pdf

Map Baernfels.jpg

Poster.pdf

Time table.pdf

Wednesday 4 October

Arrival

Opening

SAT2022-Intro.pdf

Talk: Gravitational Waves Detection

1 Gravitational wave detection

Speaker: Michèle Heurs (AEI Hannover)

Astroteilchenschule_Obertrubach_Heurs_Okt2023.pdf

17:30 Break

Participant Presentations

2 Reconstruction methods for radio detection of air showers with LOFAR

The LOw Frequency ARray (LOFAR) is a radio telescope with 38 stations of antenna fields across Europe, and it can detect the radio emission from cosmic-ray induced air showers via radio antennas in the frequency range from $30$ to $80 \ \text{MHz}$.
A current reconstruction approach is determining the shower maximum $X_\text{max}$, which can be used to deduce the mass of the primary particle. The mass composition of cosmic rays contains vital information about their origin, and with accurate measurements long-standing issues about the transition from Galactic to extragalactic origin or the nature of the cutoff observed at highest energies could be solved.

The reconstruction of the signal poses a challenge due to background noise which obscures the data. A new approach to this is Information Field Theory, which uses Bayesian inference to calculate the most likely signal for given data.

Speaker: Ms Karen Terveer (ECAP)

astroparticle_school.pdf

Dinner

Thursday 5 October

Lecture: Physics at the Pulsar Timing Frontier

3 Physics at the Pulsar Timing Frontier

Speaker: Kai Schmitz (University of Münster)

2023_10_astro_particle_school_obertrubach.pdf

Lunch / Coffee Break: Break

Lecture: Low-energy Neutrinos

4 Low-energy Neutrinos

Speaker: Caren Hagner (University of Hamburg)

Lecture1-Introduction.pdf

Lecture2-Solar-Neutrinos.pdf

Lunch / Coffee Break

Participant Presentations

5 Simulation of photon propagation in dust layers at the South Pole

The IceCube neutrino observatory instruments 1 $km^{3}$ of Antartic ice that represents the detection target and the light propagation medium. The IceCube detector instruments several thousands optical sensors, that detect Cherenkov light emitted from secondary particles (muons) created in neutrino interactions. From these photons, it is possible to reconstruct the muon (and therefore the parent neutrino) incoming direction and energy. To estimate the accuracy of these reconstructed quantities, the properties of light propagation in the ice must be well understood. As the photons propagate from the point of emission, they are affected by absorption and scattering, which must be considered for both simulation and reconstruction of IceCube data. Below about 1300 m, the ice is considered pure and clear. However, after 1300 m dust is found trapped in the ice, which represents the dominant source of scattering. Dust loggers made it possible to study the ice structure resulting in a survey of ice dust layers, that have the effect of increasing the scattering and absorption light passing through. In these layers, the propagation of photons is not isotropic, but has a preferred direction: less scattering along the glacial flow in the x-y plane, and more along the z-axis. My work is a simulation of photon propagation through thin layers of dust, to study the photon arrival time distribution at a fixed distance from the emission point, by changing the properties of the ice, such as the albedo and the layer thickness.

Speaker: Teresa Pernice

Astroparticle_school_pernice.key

Astroparticle_school_pernice.pdf

6 Analyzing parameter sets resulting from modeling by using machine learning tools

The radiation from astrophysical sources such as blazars originates mainly from various particle interactions in the jet or in other regions of the blazar. The spectral energy distribution of a blazar shows a two-bump structure. While the low-energy emission is explained by synchrotron radiation of highly energetic electrons, the high-energy part can contain contributions from hadrons too. Therefore, the radiation of a blazar can be described by leptonic, hadronic or lepto-hadronic models. Depending on the model there are various values describing properties of both the radiation source itself and the particles that produce the radiation. These parameters are used for simulating the radiation by solving the particle transport equation numerically, so that the resulting blazar spectra can be obtained. The modeled spectrum can then be compared with the observed data from the blazar. With large parameter scans, each parameter can be varied so that many spectra are obtained in the end. Several different parameter sets may describe the radiation well but lead to different physical properties of the source.
In this project, we are investigating leptonic models and focus on the parameter space overall. We compare the models that describe the data equally well. If there are large differences between the parameter sets, this could mean the properties of one and the same radiation source also differ greatly depending on the model. Furthermore, we are interested in how to optimize the modeling with these findings. Using the blazar PKS 0735+178 as an example, we visualize the parameter sets resulting from the modeling of the radiation. We apply machine learning methods for mapping the parameter space and visualization of multidimensional data. We present the maps of the parameter space and discuss the physical implications of the obtained results.

Speaker: Frederike Apel

AstroParticleSchool23_Apel.pdf

7 Data Volume Reduction for CTA

The Cherenkov Telescope Array (CTA) is a next-generation atmospheric Cherenkov gamma-ray observation which will consist of two sites, one in Paranal and another one in La Palma, and three different types of telescopes (large, medium, and small size telescopes). CTA will be coordinated by the Array Control and Data Acquisition (ACADA). ACADA will collect event data from all of the CTA telescopes and it must handle data rates between a few and a few tens of Gb/s per telescope. The total data volume for each site must be reduced to at most 5 Gb/s, which translates into an important reduction factor of ~25-30. I propose a Data Volume Reduction algorithm based on time clustering with DBSCAN after a cutoff in the signal-to-noise ratio. This method shows a good reduction factor improving the overall shower reconstruction as compared with the standard TailCuts cleaning algorithm. In addition, multiple changes to the basic principle of the time clustering algorithm have been considered and tested.

Speaker: Ms Clara Escanuela NIeves (MPIK)

dvr_Escanuela_school.pdf

8 GNN based Gamma/Hadron Separation with SWGO

The Southern Wide-field Gamma-ray Observatory (SWGO) is a next-generation ground-based gamma-ray observatory. Currently in the R&D phase, the experiment is expected to have a large array of water Cherenkov detectors (WCD) placed at high elevations in South America. This will enable precise observations of the gamma-ray sky, mainly in the regime of ~100GeV up to the PeV region. The primary background of gamma-ray observations are hadronic showers, that need to be rejected to guarantee a high signal-to-noise ratio.
Currently approaches heavily rely on hand-crafted features or employ a large number of variables which are exploited using machine learning techniques. In this talk I will discuss a novel approach for gamma/hadron separation for SWGO. Based on the great success of deep learning in engineering and science, we present an innovative classification algorithm that processes lowlevel information at station level using graph neural networks. We will examine the performance of the novel technique and compare it to a machine learning algorithm that is currently in use.

Speaker: Martin Schneider (ECAP, FAU)

SWGO_GNNs_Martin_Schneider.pdf

17:30 Break

Participant Presentations

9 Searching for TeV pulsar halos: revisiting the H.E.S.S. Galactic Plane Survey

A TeV halo is defined as the Inverse Compton emission from $e^\pm$
diffusing in the Interstellar Medium, injected by a Pulsar Wind
Nebula (PWN). The pulsars surrounded by such halos are generally
older than those powering the TeV PWNe identified in the H.E.S.S
Galactic Plane Survey (HGPS). We revisit the HGPS sources in search
of halo candidates among coincidences between TeV components and
older pulsars. We also search for coincidences in the recently
released first LHAASO source catalog. We employ a diffusion
model of the particle transport in halos to attempt to discriminate
observationally between halos and older PWNe. Finally, we outline
the recent development of more powerful H.E.S.S. analysis techniques,
including spectro-morphological fitting, hadronic shower background
models, and gas-template-based Galactic diffuse emission models,
which should yield an improved description of extended sources such
as halo candidates.

Speaker: Karim Sabri (Laboratoire Univers et Particules de Montpellier)

AP School - HGPS-5.pdf

10 Towards searching for ultra-high energy photons from galactic PeVatrons

Recently, several observatories have discovered photons of cosmic origin with maximum energies in the PeV ($10^{15}\,\text{eV}$) range. Photons at these energies might be produced as by-products from particle acceleration in so-called PeVatrons, which are widely assumed to be the source of a large part of galactic cosmic rays. The first PeVatron to be firmly established was the Crab nebula, a pulsar wind nebula. Another PeVatron is known to be located in the Galactic center region. However, the measurement of PeV photons from several other sources indicates the presence of further PeVatrons, which may also be associated to supernova remnants. In this contribution, we present a compilation of recent measurements of PeV photons by LHAASO and HAWC. We extrapolate the measured energy spectra up to the ultra-high-energy (UHE, $>10^{17}\,\text{eV}$) regime to obtain an estimate of the required sensitivity for the measurement of UHE photons from specific source candidates. One goal of this study is to evaluate the discovery potential of present and future cosmic-ray observatories, for example the Pierre Auger Observatory, to detect such photons, which could provide complementary information on the sources of cosmic rays beyond the PeV regime—a key objective of current efforts in multimessenger astronomy.
This work is supported by the Deutsche Forschungsgemeinschaft (DFG).

Speaker: Ms Chiara Jane Papior (Universität Siegen)

Astroparticle_School_Slides_ChiaraPapior_corrected_version.pdf

11 Combined fit of UHECRs with jetted AGN

We present a detailed study of the contribution of low- and high-luminosity jetted Active Galactic Nuclei (AGN) populations to the spectrum and composition of ultra-high-energy cosmic rays (UHECRs) and the corresponding EeV neutrino flux. We find that two AGN populations should have different properties to explain the UHECR data. Our results show that the dominant contribution to the neutrino flux at EeV energies comes from low-luminosity BL Lacs when using the air-shower model EPOS-LHC, while contribution of high-luminosity BL Lacs is required when using SIBYLL 2.3d. We also find that the contribution of flat-spectrum radio quasars (FSRQs) is not constrained by a fit of UHECR, but the inclusion of FSRQ is necessary to detect the neutrino flux from AGN with future instruments.

Speaker: Pavlo Plotko (Deutsches Elektronen-Synchrotron DESY)

Plotko_AS_10_04_new.pdf

Dinner

Friday 6 October

Lecture: Low-energy Neutrinos

12 Low-energy Neutrinos

Speaker: Caren Hagner (University of Hamburg)

Lecture3-Neutrino-Oscillations.pdf

Lecture4-3flavor-JUNO.pdf

Lunch / Coffee Break: Break

Lecture: Physics at the Pulsar Timing Frontier

13 Physics at the Pulsar Timing Frontier

Speaker: Kai Schmitz (University of Münster)

2023_10_astro_particle_school_obertrubach.pdf

Lunch / Coffee Break

Lecture: Low-energy Neutrinos

14 Low-energy Neutrinos

Speaker: Caren Hagner (University of Hamburg)

Lecture5-Supernova-Geoneutrinos.pdf

Lecture6-doublebeta.pdf

17:30 Break

Participant Presentations

15 Operating a LXe detector test platform

As liquid xenon (LXe) dark matter detectors grow in size with each experiment, larger components come with larger challenges that new designs might solve. The Xenon Based Research Apparatus (XeBRA) is a small test platform in Freiburg where new components and configurations are explored. The test platform is now being setup to test a new kind of photosensor, a digital silicon photomultiplier, aiming to greatly reduce the natural radioactivity of photosensors, the major issue of currently widely used photomultiplier tubes.

Speaker: Tiffany Luce

AstroSchool23.pdf

16 Design and operation of a co-deployed dust-logging instrument for the IceCube Upgrade and IceCube-Gen2

A precise understanding of the optical properties of the instrumented Antarctic ice sheet is crucial to the performance of optical Cherenkov telescopes such as the IceCube Neutrino Observatory and its planned successor, IceCube-Gen2.
One complication arising from the large envisioned footprint of IceCube-Gen2 is the larger impact of the so-called ice tilt, which describes the undulation of layers of constant optical properties as a function of depth and transverse position in the detector.
Within IceCube tilt modeling has originally been based on stratigraphy measurements performed by a stand-alone laser dust logger. More recently, it has been independently be deduced using calibration data from LEDs located in the photosensor modules.
In this talk, I will summarize the ice optical modeling with an emphasis on tilt and describe a newly started project to replace the stand-alone dust logger with a light source that can be co-deployed with the photosensor modules and operated during the deployment of the detector. The newly developed device is planned to be tested during the deployment of the IceCube Upgrade in 2025/26, so to ensure success during IceCube-Gen2.

Speaker: Anna Eimer

AP_school_Anna_Eimer_v4.pdf

17 The XENONnT cryogenic radon removal system

The XENONnT experiment, located underground at the Laboratori Nazionali del Gran Sasso, uses a total of 8.6t of high-purity liquid xenon to directly search for WIMP (weakly interacting massive particle) dark matter using a dual phase time projection chamber. A predominant part of the detector's low-energy background is caused by intrinsic contamination of the xenon with Rn-222, which is continuously emanating from the detector materials. For the reduction of this background, a high-flow online radon removal system was designed and constructed (M. Murra et al., Eur. Phys. J. C 82 (2022) 1104), which uses cryogenic distillation based on the difference in vapor pressure between radon and xenon. The system can be run concurrently in two modes of operation: At a flow rate of 200 slpm, liquid xenon is extracted from the detector and passed through the system, which results in a reduction in radon concentration by a factor of two. An additional flow of 25 slpm of gaseous xenon is extracted from regions with high radon emanation (cables, feed lines, ...) providing another reduction factor of about two. With the combined operation of both modes, an extremely low Rn-222 activity concentration of < 1 µBq/kg is achieved. This unprecedentedly low radon concentration marks a new world record, and sets the bar for the lowest concentration in any xenon dark matter experiment today. This project is supported by BMBF Verbundforschung under 05A20PM1 and 05A23PM1.

Speaker: David Koke (Westfälische Wilhelms-Universität Münster, Germany)

Koke_Obertrubach_RAD_Talk_pdf_06.10.2023.pdf

Dinner

Evening lecture: Deutsches Zentrum für Astrophysik - DZA

18 Deutsches Zentrum für Astrophysik - DZA

Speaker: Christian Stegmann

Saturday 7 October

Participant Presentations

19 ${}^{\text{83m}}$Kr N-line spectrum measurement at KATRIN

In the KArlsruhe TRItium Neutrino (KATRIN) experiment we perform a precision measurement of the tritium beta decay spectrum. Our goal is to determine the neutrino mass by investigating the spectrum shape near the endpoint region at around $18.6$ keV. Recently we have published a new direct upper limit on neutrino mass of $0.8$ eV/c${}^2$ (90% C.L.) which has been obtained with only 5% of the anticipated total measurement time. However, reaching the target sensitivity of $0.2$ eV/c${}^2$ at 90% C.L. not only requires the full measurement time, but also the detailed study of systematic measurement uncertainties. Several of them can be studied by measuring a shape distortion of the ${}^{\text{83m}}$Kr electron conversion lines which are commonly used for calibration purposes of different (astro-)particle physics experiments. This creates high demands on precise knowledge of the undistorted krypton spectrum.

In KATRIN we use the $32$ keV N-lines lying in the high energy region of the ${}^{\text{83m}}$Kr spectrum including the weaker N$_\text{1}$ line. In this talk I will present current results of a dedicated ${}^{\text{83m}}$Kr electron N-spectrum measurement with emphasis on N$_\text{1}$ line conducted at KATRIN.

Speaker: Jaroslav Storek (Karlsruher Institut für Technologie)

StorekKrHeKATRIN_v2.pdf

20 Ultra-low intrinsic background for the direct dark matter search down to the neutrino fog with DARWIN/XLZD

On the various astrophysical and cosmological scales there is compelling evidence for the existence of dark matter beyond the constituents of our Standard Model of particle physics. WIMPs are among the favored candidates which would solve also other problems of the Standard Model. The DARWIN Collaboration and/or the XLZD Consortium plan a next generation xenon detector with 40t (or up to 80t) of active mass to probe WIMPs down to the region of the neutrino fog, where the background is governed by coherent elastic neutrino nucleus scattering (CEvNS) of solar and atmospheric neutrinos. The DARWIN/XLZD detector will be an observatory with a brought physics program including solar neutrinos, solar axions, ALPs and neutrinoless double beta decay.
DARWIN/XLZD requires again another order of magnitude in reducing the background rate compared to the current set of experiments (LZ, PandaX-4T, XENONnT). In addition to going underground, muon and neutron vetos, careful material screening and selection, the reduction of radioactive noble gases as Kr-85 and Rn-222 is of very high importance. Within the ERC Advanced Grant project "LowRad" the technology is being developed to reduce these backgrounds in DARWIN/XLZD to 10% of the rate induced by unshieldable solar neutrinos.
The author is supported by the ERC AdG project "Lowrad" (101055063)

Speaker: Philipp Schulte (Institut für Kernphysik, Universität Münster)

Vortrag.pdf

21 DISCO Experiment

DISCO (Directionality in Scintillation Observer) is a lab-scale experiment built at the University of Mainz to characterize water-based liquid scintillators (WbLS) and demonstrate the ability to separate Cherenkov and Scintillation light. It consists of three main components: the muon tracker, the test cell, and the light detection system. The test cell can be filled with water, a scintillator, or WbLS. DISCO uses cosmic muons for characterizing different detection mediums. The interaction of muons with the detection medium produces photons, which are detected by the light detection system. The light detection system consists of an array of fast 1-inch photomultiplier tubes (PMT) with sub-nanosecond time resolution. There is also a provision to replace the PMTs with LAPPDs in the future. The PMT signals are stored and processed offline to extract the photon hit-time and charge deposited in each PMT. This information is then used to reconstruct the tracks of the muon passing through the test cell. This talk discusses the experimental set-up of DISCO and the track reconstruction procedure.

Speaker: Amala Augusthy (JGU Mainz)

Amala_DISCO_Erlangen_Final.pdf

DISCO_Abstract_Erlangen.pdf

Erlangen_DISCO.pdf

22 Supernova neutrino detection with dual-phase xenon TPCs

Astrophysical neutrinos are a great tool to study physics beyond the standard model of particle physics (BSM), one such source being galactic supernovae (SN). While these neutrinos can be detected by traditional neutrino detectors via the production of their charged lepton partners, they undergo the neutral current (NC) Coherent Elastic Neutrino Nucleus Scattering (CE$\nu$NS) process. These neutrinos, being typically of MeV energies, produce nuclear recoils (NRs), with kinetic energies of $E^2_\nu/M$, which are in the range of few to a few tens of keV. In addition, the coherent enhancement of the cross-section of the CE$\nu$NS process becomes particularly important in these energy ranges. Therefore, in order to detect these signals, detectors with very low thresholds and high nucleon number ($A$) are required. Large volume dual-phase liquid xenon TPCs, primarily designed to detect WIMPS, are therefore very suitable to detect such signals because of both very low backgrounds (as a result low thresholds) and high mass number. In this talk I will discuss the observable signals for SN neutrinos in xenon TPCs and the different backgrounds that affect these measurements. In this respect I will also discuss the possible limitations due to the charged-current (CC) interactions of the SN neutrinos.

Speaker: Dr Sayan Ghosh (Purdue University)

Presentation_SayanGhosh_v2.pptx

10:45 Break

Lecture: Physics at the Pulsar Timing Frontier

23 Physics at the Pulsar Timing Frontier

Speaker: Kai Schmitz (University of Münster)

2023_10_astro_particle_school_obertrubach.pdf

Lunch / Coffee Break

Talk: eROSITA

17:30 Break

Participant Presentations

Dinner

Sunday 8 October

Free

Monday 9 October

Lecture: Galactic cosmic rays

24 Galactic Cosmic Rays

Speaker: Philipp Mertsch (RWTH Aachen)

Mertsch_ECAP-school_2023-lecture1.pdf

Lunch / Coffee Break: Break

Lecture: Galactic cosmic rays

25 Galactic cosmic rays

Speaker: Philipp Mertsch (RWTH Aachen)

Mertsch_ECAP-school_2023-lecture2.pdf

Lunch / Coffee Break

Workshop: Proposal writing mini‐workshop

26 Proposal writing mini‐workshop

Speaker: Anna Nelles

Lunch / Coffee Break: Break

Workshop: Proposal writing mini-workshop

27 Proposal writing mini-workshop

Speaker: Anna Nelles

Funding_Proposal_Workshop.pdf

Dinner

Tuesday 10 October

Talk: SWGO

28 SWGO

Speaker: Wayne Springer (University of Utah)

Lunch / Coffee Break: Break

Lecture: Galactic Cosmic Rays

29 Galactic Cosmic Rays

Speaker: Philipp Mertsch (RWTH Aachen)

Mertsch_ECAP-school_2023-lecture3.pdf

Lunch / Coffee Break

Group Photo

Lecture: Higgs physics

30 Higgs physics

Speaker: Sarah Heim (DESY)

Lunch / Coffee Break: Break

Participant Presentations

31 Analysing the Fermi Bubbles using improved models and datasets

\documentclass{article}
\usepackage{graphicx} % Required for inserting images
\usepackage{hyperref}
\usepackage{siunitx}
\usepackage{gensymb}
\pagenumbering{gobble}
\DeclareSIUnit\parsec{pc}
\title{Analysing the Fermi Bubbles\
\large using improved models and datasets}
\author{Paul-Simon Blomenkamp\ \href{mailto:paul-simon.blomenkamp@astro.ruhr-uni-bochum.de}{paul-simon.blomenkamp@astro.ruhr-uni-bochum.de} }

\date{July 2023}

\begin{document}

\maketitle

\section{Abstract}
The Fermi Bubbles remain one of the largest unexplained objects in the gamma ray sky. The two lobes, which appear to originate close to the galactic center and extend some
50$\degree$ perpendicular to the galactic plane, have spurred discussions about the recent history of our Milky Way. While their origin is not yet understood, various ideas have been presented, such as past AGN jet activity from the SMBH in the
galactic center, as well as a starburst scenario.\
This work studies the spectrum and morphology of the Fermi Bubbles, which need to be well understood to evaluate the current theories regarding the nature of the bubbles. \
In this study, 12 years of Fermi LAT data and state-of-the-art diffuse emission models are used to analyse the bubbles using all-sky fits in a template fitting approach. I present the effect of the different models on the spectrum, as well as possible spatial variations.

\end{document}

Speaker: Paul-Simon Blomenkamp (Ruhr-Universität Bochum)

BlomenkampObertrubach2023.pdf

32 Studies on the effects of magnetic fields on anisotropies in a catalog based search

Ultra high energy cosmic rays are charged particles originating from various astrophysical sources and they exhibit anisotropic distributions in their arrival directions at Earth. Several studies have been conducted by the Pierre Auger Observatory on the arrival directions of such particles by employing a likelihood analysis which showed that the starburst galaxies (SBG) model have a better agreement than the hypothesis of isotropy with a 4$\sigma$ significance. Although in these analysis the role of the galactic magnetic field (GMF) has not been considered. The GMF is expected to play a key role in the arrival direction of charged particles and understanding its role in shaping these anisotropies is of great importance in grasping the mechanisms governing cosmic ray propagation and their sources.

To address this, we created simulated datasets based on the SBG catalog on which we conducted the likelihood analysis employed by the Pierre Auger Collaboration. The datasets have been constructed by adding an isotropic background to the signal events which have been generated with CRPropa3. The model by Jansson & Farrar (JF12) has been employed as the GMF and a lens has been created to apply its effects to the simulated events.

Our analysis revealed that in 20% of the simulated datasets, it was possible to recover a compatible set of best-fit parameters. However, it was noted that the true anisotropy fraction needed to be increased due to the effect that the elements which dominate the spectrum at high energy are highly isotropized.

Speaker: Mr Luca Deval

04_Deval_AS.pdf

33 Modified Temperature Redshift relation and UHECR propagation

The existing discrepancies between the observation of local and extraction of global cosmological parameters motivate an extension of the ΛCDM cosmological model. A proposed extension called SU(2)_CMB describes cosmic microwave background (CMB) photons with an SU(2) instead of a U(1) gauge group. This mitigates some of these tensions, for example 𝐻0, Ω𝑚, 𝜎8, pushes the recombination epoch to higher redshifts, and thereby effectively reduces CMB photon densities.

In this contribution, I would like to discuss the impact of the SU(2) modified CMB evolution on the propagation of ultra-high energy cosmic rays (UHECRs) and their related fluxes of cosmogenic photons and neutrinos. The measured and predicted fluxes are the basis used to constrain source properties and rely on the ΛCDM CMB evolution. Thus, a modification of the past CMB densities impacts these flux predictions and possibly the constraints on the sources. In particular, we show an increased proton flux below the ankle (10^18.5 eV), and slightly increased cosmogenic neutrino fluxes in comparison to ΛCDM.

Speaker: Janning Meinert (Bergische Universität Wuppertal)

2023.10.09 Obertrubach.pptx

Dinner

Evening lecture: Research Funding in Germany and Europe

34 Research Funding in Germany and Europe

Speaker: Marc Hempel (PT.DESY)

mh_forschungsfoerderung2023.pdf

Wednesday 11 October

Lecture: Higgs physics

35 Higgs physics

Speaker: Sarah Heim (DESY)

Lunch / Coffee Break: Break

Workshop: Proposal writing workshop feedback

36 Proposal writing workshop feedback

Speaker: Anna Nelles

Feedback Session: Feedback Session (if there is time)

Lunch / Coffee Break

Feedback Session: Feedback Session (alternative time)

Participant Presentations

37 Constraining the VSR origin of graviton mass through binary pulsars

Very Special Relativity (VSR) is a particular realization of Lorentz violation, which was presented for the first time by Cohen and Glashow in 2006 with the idea of introducing an alternative mechanism for neutrinos' masses. Since then, the ideas of VSR have been applied to many different areas. In this talk, after a short introduction to the key features of VSR, I will present its application to linearized gravity: we will see how, within the framework of VSR, it is possible to construct a coherent spin-2 free field theory, preserving the usual gauge invariance of linearized General Relativity while, at the same time, allowing for a non-zero graviton mass. Then, in an effective field theory approach, we will analyse the tree-level rate of gravitational emission $\frac{dE}{dt}$ from a classical source and apply those results to the case of binary stars, for which we are able to find the formula for the orbital period derivative $\dot P$ in VSR. In conclusion, using data from the two binary systems PSR B1913+16 and PSR J0737-3039, we estimate upperbounds on the VSR origin of a graviton mass around $10^{-21}eV$.

Speakers: Alessandro Santoni (Pontificia Universidad Católica de Chile / TU Wien), Alex Soto

VSR_binaries_ppt.pdf

38 KM3NeT/ARCA offline follow-up of X-rays flares of Extreme Blazar sources

Extreme high-energy peaked BL Lac objects (EHBLs) are an emerging class of Blazars with specific spectral properties, characterized by synchrotron emission peaking in the hard X-rays band and inverse compton emission peaking at TeV energies, possible sources energy extra-galactic neutrinos. The presence of a jet extending up to hundreds of Kiloparsec can guarantee the acceleration of CRs up to UHEs. The photopion interactions with seed synchrotron photons of such high energies are expected to produce neutrinos of several TeVs, thus nicely matching the energy window of the KM3NeT/ARCA, an underwater Cherenkov telescope dedicated to the study of cosmic neutrinos currently under construction in the Mediterranean Sea. While the detector is being steadily expanded to reach its full scientific potential, ARCA already started taking data in May 2021. I will discuss a search for astrophysical neutrino emission from Extreme Blazar with ARCA, focusing on possible time-correlations with their flaring status.

Speaker: Maria Rosaria Musone (Università degli Studi della Campania "L. Vanvitelli ")

presentation to Astroparticle school.pdf

39 Reconstruction of faint non-standard model particles in IceCube

The new Faint Particle Trigger (FPT) in IceCube was developed with the intention of reaching a higher sensitivity for faint signals in the IceCube detector. Instead of customary triggers, which are based on local coincidences between multiple modules in the detector, it also uses isolated hits. Therefore it is especially suited for the search for faint signals in the detector. Examples are fractionally charged particles, which should produce less Cherenkov light in comparison to muons because of their smaller charge, or other non-standard model particles.
This presentation shows first efforts in reconstructing events that were triggered by the FPT. It focusses on existing cleaning and reconstruction methods used in IceCube and investigations on how these can be adapted to take advantage of the additional hits which are registered by the FPT. Additionally reconstruction methods based on machine learning will be adapted to the new triggered events in the future.

Speaker: Nick Jannis Schmeisser

Vortrag Astroparticles school 2023 Nick Schmeißer pdf-version.pdf

40 Tuning of the Pythia8 hadronic interaction model for simulations of UHECR induced air showers

Understanding the properties of extensive air showers (EAS) is of prime importance for extracting the properties of ultra high-energy cosmic rays from data, such as collected by the Pierre Auger Observatory. Inferring their primary energy and, most importantly, their primary mass relies on detailed comparisons of EAS measurements with corresponding air shower simulations. The largest uncertainties in such simulations are caused by limited knowledge of hadronic interactions at high energies.

To assess the effect of such uncertainties, different hadronic interactions are applied in EAS simulations, each of them being tuned to accelerator data. Pythia8 is a hadronic interaction model that is frequently used in the context of LHC experiments and is well suited to be tuned to accelerator data, but up to now has only rarely been used in EAS simulations. New implemented features were added to the Angantyr model of Pythia8 aiming for a better description of hadron-nucleus interactions.

This contribution focuses on studying $p_T$-integrated identified particle spectra from negatively charged pion-carbon fixed-target collisions at NA61/SHINE and comparing them against the newest version of Pythia8. The validity of the Angantyr model to describe the experimental datasets is investigated using the RIVET interface. A tune of Pythia8 will be discussed in a second time as well as the effects of the fit parameters on muon production in EAS.

Speaker: Chloé Gaudu (Bergische Universität Wuppertal)

11.10.2023_Gaudu.pdf

Lunch / Coffee Break: Break

Talk: eROSITA

41 eROSITA

Speaker: Jörn Wilms

atschule2023.pdf

Dinner

Thursday 12 October

Lecture: Higgs physics

42 Higgs physics

Speaker: Sarah Heim (DESY)

Lunch / Coffee Break

Talk: EHT black hole imaging and modelling

43 EHT black hole imaging and modelling

Speaker: Christian Fromm (JMU Würzburg)

Lunch / Coffee Break

Departure