Publications

Order by: publication date number of citations

• Ephemeral Learning - Augmenting Triggers with Online-Trained Normalizing Flows

  Anja Butter, Sascha Diefenbacher, Gregor Kasieczka, Benjamin Nachman, Tilman Plehn, David Shih, Ramon Winterhalder

  SciPost Phys. 13, 087 (2022) · published 7 October 2022 | Toggle abstract · pdf

  The large data rates at the LHC require an online trigger system to select relevant collisions. Rather than compressing individual events, we propose to compress an entire data set at once. We use a normalizing flow as a deep generative model to learn the probability density of the data online. The events are then represented by the generative neural network and can be inspected offline for anomalies or used for other analysis purposes. We demonstrate our new approach for a toy model and a correlation-enhanced bump hunt.

  9 citations

• Many-gluon tree amplitudes on modern GPUs: A case study for novel event generators

  Enrico Bothmann, Walter Giele, Stefan Hoeche, Joshua Isaacson, Max Knobbe

  SciPost Phys. Codebases 3 (2022) · published 23 August 2022 | Toggle abstract · pdf

  The compute efficiency of Monte-Carlo event generators for the Large Hadron Collider is expected to become a major bottleneck for simulations in the high-luminosity phase. Aiming at the development of a full-fledged generator for modern GPUs, we study the performance of various recursive strategies to compute multi-gluon tree-level amplitudes. We investigate the scaling of the algorithms on both CPU and GPU hardware. Finally, we provide practical recommendations as well as baseline implementations for the development of future simulation programs. The GPU implementations can be found at: https://www.gitlab.com/ebothmann/blockgen-archive.

  8 citations

• DELight: A Direct search Experiment for Light dark matter with superfluid helium

  Belina von Krosigk, Klaus Eitel, Christian Enss, Torben Ferber, Loredana Gastaldo, Felix Kahlhoefer, Sebastian Kempf, Markus Klute, Sebastian Lindemann, Marc Schumann, Francesco Toschi, Kathrin Valerius

  SciPost Phys. Proc. 12, 016 (2023) · published 3 July 2023 | Toggle abstract · pdf

  To reach ultra-low detection thresholds necessary to probe unprecedentedly low Dark Matter masses, target material alternatives and novel detector designs are essential. One such target material is superfluid $^4$He which has the potential to probe so far uncharted light Dark Matter parameter space at sub-GeV masses. The new "Direct search Experiment for Light dark matter", DELight, will be using superfluid helium as active target, instrumented with magnetic micro-calorimeters. It is being designed to reach sensitivity to masses well below 100 MeV in Dark Matter-nucleus scattering interactions.

  8 citations

• Dark Matter direct detection of classical WIMPs

  Jodi Cooley

  SciPost Phys. Lect. Notes 55 (2022) · published 20 May 2022 | Toggle abstract · pdf

  One of the highest priorities in particle physics today is the identification of the constituents of dark matter. This manuscript is a supplement to pedagogical lectures given at the 2021 Les Houches Summer School on Dark Matter. The lectures cover topics related to the direct detection of WIMP dark matter, including the distribution of dark matter, nuclear scattering, backgrounds, planning and designing of experiments, and a sampling of planned and ongoing experiments.

  8 citations

• Class imbalance techniques for high energy physics

  Christopher W. Murphy

  SciPost Phys. 7, 076 (2019) · published 5 December 2019 | Toggle abstract · pdf

  A common problem in a high energy physics experiment is extracting a signal from a much larger background. Posed as a classification task, there is said to be an imbalance in the number of samples belonging to the signal class versus the number of samples from the background class. In this work we provide a brief overview of class imbalance techniques in a high energy physics setting. Two case studies are presented: (1) the measurement of the longitudinal polarization fraction in same-sign $WW$ scattering, and (2) the decay of the Higgs boson to charm-quark pairs.

  8 citations

• The WIMP paradigm: Theme and variations

  Jonathan L. Feng

  SciPost Phys. Lect. Notes 71 (2023) · published 13 June 2023 | Toggle abstract · pdf

  WIMPs, ↑ weakly-interacting massive particles, have been leading candidates for particle dark matter for decades, and they remain a viable and highly motivated possibility. In these lectures, I describe the basic motivations for WIMPs, beginning with the WIMP miracle and its under-appreciated cousin, the discrete WIMP miracle. I then give an overview of some of the basic features of WIMPs and how to find them. These lectures conclude with some variations on the WIMP theme that have by now become significant topics in their own right and illustrate the richness of the WIMP paradigm.

  7 citations

• A no-go theorem for non-standard explanations of the $\tau\to K_S\pi\nu_\tau$ CP asymmetry

  Vincenzo Cirigliano, Andreas Crivellin, Martin Hoferichter

  SciPost Phys. Proc. 1, 007 (2019) · published 18 February 2019 | Toggle abstract · pdf

  A new tensor interaction is the only possibility to explain the $2.8\sigma$ tension observed by the BaBar collaboration in the CP asymmetry in $\tau\to K_S\pi\nu_\tau$ with physics beyond the Standard Model (BSM) realized above the electroweak scale. However, the strong phase generated by the interference between vector and tensor phases is suppressed by at least two orders of magnitude due to Watson's final-state-interaction theorem, and the strength of the CP-violating tensor interaction is strongly constrained by bounds from the neutron electric dipole moment and $D$-$\bar{D}$ mixing. As a result, a confirmation of the tension at Belle II would point to light BSM physics.

  7 citations

• Whac-a-constraint with anomaly-free dark matter models

  Sonia El Hedri, Karl Nordström

  SciPost Phys. 6, 020 (2019) · published 7 February 2019 | Toggle abstract · pdf

  Theories where a fermionic dark matter candidate interacts with the Standard Model through a vector mediator are often studied using minimal models, which are not necessarily anomaly-free. In fact, minimal anomaly-free simplified models are usually strongly constrained by either direct detection experiments or collider searches for dilepton resonances. In this paper, we study the phenomenology of models with a fermionic dark matter candidate that couples axially to a leptophobic vector mediator. Canceling anomalies in these models requires considerably enlarging their field content. For an example minimal scenario we show that the additional fields lead to a potentially much richer phenomenology than the one predicted by the original simplified model. In particular collider searches for pair-produced neutralinos and charginos can be more sensitive than traditional monojet searches in thermally motivated parts of the parameter space where the mediator is outside the reach of current searches.

  6 citations

• OASIS: Optimal Analysis-Specific Importance Sampling for event generation

  Konstantin T. Matchev, Prasanth Shyamsundar

  SciPost Phys. 10, 034 (2021) · published 15 February 2021 | Toggle abstract · pdf

  We propose a technique called Optimal Analysis-Specific Importance Sampling (OASIS) to reduce the number of simulated events required for a high-energy experimental analysis to reach a target sensitivity. We provide recipes to obtain the optimal sampling distributions which preferentially focus the event generation on the regions of phase space with high utility to the experimental analyses. OASIS leads to a conservation of resources at all stages of the Monte Carlo pipeline, including full-detector simulation, and is complementary to approaches which seek to speed-up the simulation pipeline.

  6 citations

• Current status and prospects of muonium spectroscopy at PSI

  B. Ohayon, Z. Burkley, P. Crivelli

  SciPost Phys. Proc. 5, 029 (2021) · published 6 September 2021 | Toggle abstract · pdf

  Recent and ongoing developments of low energy muon beamlines are heralding a new era of precision Muonium spectroscopy. While past spectroscopic measurements of Muonium were performed at pulsed muon facilities and were statistically limited, the advent of continuous low energy muon beams, such as at the LEM beamline at PSI, paired with the development of efficient muon-muonium converters and laser advancements, will overcome these limitations. Current experiments presently underway at the LEM facility and in the near future at the muCool beamline, which is under development at PSI, aim to improve the precision of both the 1S-2S transition determination and Lamb shift by several orders of magnitude. In this Chapter we give an overview of the current status and future prospects of these activities at PSI, highlighting how their projected significance fits into a broader context of other ongoing efforts worldwide.

  6 citations