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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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.
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...
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...
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...
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...
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.
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...
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...
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...
