Conveners
Tuesday afternoon: Tuesday afternoon
- Christian Ohm (KTH Royal Institute of Technology (SE))
- David Marsh
Machine learning has been successfully used in physics research for decades. With the advent of deep learning methods in computer science, a renaissance of machine learning in physics occurred in recent years. The seminar explains the basic ideas of deep learning, distinguishes deep learning from the classic data analysis and classic machine learning approaches and explains concepts and...
IceCube is an astrophysical neutrino detector that uses photosensors embedded in a cubic kilometer of glacial ice at the South Pole. Over the past decade, IceCube has discovered a diffuse, high-energy flux of extragalactic neutrinos, and has reported the first likely multimessenger association involving high energy neutrinos.
In light of these findings, we are now looking towards the...
Ultra-high energy (UHE) neutrinos (E > 1e16 eV) are connected to the most energetic phenomena in our universe and neutrino astronomy is a powerful tool to study the high-energy universe. Neutrinos can escape dense source environments and point back to their sources with sub-degree accuracy. In particular, multi-messenger analyses that combine neutrino detection with electromagnetic (e.g. gamma...
In the presence of an external magnetic field, the axion and the photon mix. In particular, the dispersion relation of a longitudinal plasmon always crosses the dispersion relation of the axion (for small axion masses), thus leading to a resonant conversion. While often neglected in the literature, these conversions can dominate axion production or absorption. Using thermal field theory and...
The IceCube detector has components drilled 2 km into the ice. While the depth has been calibrated so far there is no calibration for any horizontal shift from nominal. I will present the idea behind my calibration project and some results from proof of concepts.
High-energy neutrino astronomy has become a powerful tool to explore the most extreme environments in our universe. High energy neutrinos are detected most efficiently via the Askaryan effect in ice, where a particle cascade induced by the neutrino interaction produces coherent radio emission. There are several pilot radio arrays at the moment, among them ARIANNA at the Ross Ice Shelf and the...
IceCube monitors our galaxy for supernovae using neutrinos with energies of tens of MeV. However, the shock between the ejecta and the progenitor star's circumstellar material can create a high flux of neutrinos with energies on the order of TeV and above. These neutrinos would reach Earth 0.1 day - 1 year after the low-energy neutrinos. I will describe an analysis aimed to investigate whether...
Blazars are among the most powerful emitters in the Universe over a broad range of wavelengths. The recent association of TXS 0506+056 with an astrophysical neutrino and observation of a neutrino excess from its direction by IceCube has further strengthened the case for the presence of a hadronic component in their emission, and paved way for efforts to detect this component by linking it to...
In this collaboration between pure mathematics and cosmology we show that in de Sitter, bounce solutions, or the instanton configurations that trigger vacuum decay during inflation, are O(4) symmetric. This fact has so far been assumed through analogy with the flat spacetime case but never proved. The proof follows from recent progress in geometric PDE and min-max methods
Beyond the Standard Model physics (BSM) is one of the major contributions from the ATLAS groups in Sweden. This talk highlights recent BSM analyses, such as searches for dark matter and long-lived particles, in R-parity conserving and R-parity violating scenarios. Other results from the 139 fb-1 LHC data collected by the ATLAS detector are also presented, such as the search for massive...
The ATLAS experiment, located at the Large Hadron Collider (LHC) at CERN, uses a detector design optimized for the collection of data for a wide range of physics studies.
The experiment will benefit greatly from the upcoming High Luminosity LHC (HL-LHC) upgrade, which will provide higher luminosities, making new discoveries and higher-precision measurements possible.
Higher luminosity...
The existence of baryon number violating processes is considered a necessary condition to explain the observed matter-antimatter asymmetry in the universe. The construction of the European Spallation Source (ESS) provides a unique opportunity to exploit a high intensity beam of free, cold neutrons to perform searches for baryon number violation. The NNBAR/HIBEAM experiment will be the...
Traditional decision-making processes require that data is collected first, then analyzed. This model is not sustainable when the quantity of data is too large to be recorded for subsequent analysis. The Large Hadron Collider at CERN collides protons up to 30 million times per second: the majority of these events need to be rejected to comply with data processing and storage constraints. While...
The Tile Calorimeter (TileCal) of ATLAS is a hadronic calorimeter system placed in the central region of the detector. Muons deposit energy according to a well known distribution as ionization, which makes them ideal particles for energy calibration. The study is performed using muons produced in decays of $W$ bosons in LHC Run-2 data at $\sqrt{s}=13$ TeV recorded by the ATLAS detector. The...
Several HH searches are already being performed in ATLAS with different final states, but no evidence of SM-like HH production is expected until High-Luminosity LHC. The associated production of a single Higgs boson via ZH is a background in HH searches. When considering ZH, the cross-section is larger than for the corresponding SM-like HH channel. A slight modification of the HH searches to...
One of the unanswered questions remaining in particle physics is “What is Dark Matter?”. There are many different ways of searching for it; directly, indirectly, and in colliders. However, since so little is still known about it, theoretical attempts to describe it are as different as they are many. In my talk, I will describe the analysis that I am performing within the ATLAS experiment at...
The NNBAR experiment would look for neutrons transforming to antineutrons with a sensitivity improvement of three orders of magnitude compared with the previous search. At the last search, cosmic particles were the dominant background. Understanding the signature that cosmic particles leave in the NNBAR detector is therefore crucial. In this talk, predictions of cosmic ray backgrounds made...
