Publications

Order by: publication date number of citations

• Non-topological edge-localized Yu-Shiba-Rusinov states in CrBr$_3$/NbSe$_2$ heterostructures

  Jan P. Cuperus, Daniel Vanmaekelbergh, Ingmar Swart

  SciPost Phys. 18, 141 (2025) · published 28 April 2025 | Toggle abstract · pdf

  Topological superconductivity is predicted to emerge in certain magnet-superconductor hybrid systems. Here, we revisit the heterostructure of insulating monolayer CrBr$_{3}$ and NbSe$_{2}$, for which different conclusions on the presence of topological superconductivity have been reported. Using low-temperature scanning tunneling microscopy and (shot noise) spectroscopy, we find that the superconducting gap well inside the CrBr$_{3}$ islands is not affected by magnetism. At the island edges, we observe Yu-Shiba-Rusinov (YSR) states at a variety of in-gap positions, including zero energy. The absence of topological superconductivity is verified by extensive dI/dV measurements at the CrBr$_{3}$ island edges. Our results ask for a more detailed understanding of the interaction between magnetic insulators and superconductors.

• Studying mass generation for gluons

  Gernot Eichmann, Jan M. Pawlowski

  SciPost Phys. Proc. 6, 018 (2022) · published 31 May 2022 | Toggle abstract · pdf

  In covariant gauges, the gluonic mass gap in Yang-Mills theory manifests itself in the basic observation that the massless pole in the perturbative gluon propagator disappears in nonperturbative calculations, but the origin of this behavior is not yet fully understood. We summarize a recent study of the respective dynamics with Dyson-Schwinger equations in Landau-gauge Yang-Mills theory. We identify the parameter that distinguishes the massive Yang-Mills regime from the massless decoupling solutions, whose endpoint is the scaling solution. Similar to the PT-BFM scheme, we find evidence that mass generation in the transverse sector is triggered by longitudinal massless poles.

• Calculation of asymptotic normalization coefficients in the complex-ranged Gaussian basis

  Dinmukhamed A. Sailaubek, Olga A. Rubtsova

  SciPost Phys. Proc. 3, 043 (2020) · published 27 February 2020 | Toggle abstract · pdf

  A new technique towards finding asymptotic normalization coefficients in the complex-ranged Gaussian basis is presented. It is shown that a diagonalisation procedure for the total Hamiltonian matrix in the given basis results in approximation for a radial part of the bound state wave function from the origin up to the far asymptotic distances, which allows to extract ANCs rather accurately. The method is illustrated by calculations of single-particle ANCs for nuclei bound states in cases of non-local nucleon-nucleus interactions, in particular, phenomenological global potentials with the Perey-Buck's non-locality.

• Response functions and cross sections for inclusive neutrino scattering off $^2$H, $^3$H and $^3$He

  Alessandro Grassi, Jacek Golak, Roman Skibiński, Kacper Topolnicki, Henryk Witała, Hiroyuki Kamada, Laura Elisa Marcucci

  SciPost Phys. Proc. 3, 031 (2020) · published 26 February 2020 | Toggle abstract · pdf

  For several decades there has been an interest in studying neutrino scattering on light nuclei, with the hope of increasing knowledge about the theory of weak interactions and electroweak unification. A study of several neutrino induced reactions on light nuclei ($^2$H, $^3$H and $^3$He) is presented here. The cross section for these reactions is evaluated using the nuclear response functions, which holds the information about the nuclear interactions and structure. This approach has been tested for break-up reactions on the deuteron before and is now extended to three-nucleon break-up reactions.

• Inclusive decays of heavy quark hybrids

  Abhishek Mohapatra

  SciPost Phys. Proc. 6, 008 (2022) · published 31 May 2022 | Toggle abstract · pdf

  In order to understand the nature of the XYZ particles, theoretical predictions of the various XYZ decay modes are essential. In this work, we focus on the semi-inclusive decays of heavy quarkonium hybrids into traditional quarkonium in the EFT framework. We begin with weakly coupled potential NRQCD effective theory that describes systems with two heavy quarks and incorporates multipole expansions and use it to develop a Born-Oppenheimer effective theory (BOEFT) to describe the hybrids and compute the semi-inclusive decay rates. We compute both the spin-conserving and spin-flipping decay rates and find that our numerical results of the decay rates are different from the previous studies. We also develop a systematic framework in which the theoretical uncertainty can be systematically improved.

• The Compton Amplitude, lattice QCD and the Feynman-Hellmann approach

  K.U. Can, A. Hannaford-Gunn, R. Horsley, Y. Nakamura, H. Perlt, P.E.L. Rakow, E. Sankey, G. Schierholz, H. Stuben, R.D. Young, J.M. Zanotti

  SciPost Phys. Proc. 6, 003 (2022) · published 31 May 2022 | Toggle abstract · pdf

  A major objective of lattice QCD is the computation of hadronic matrix elements. The standard method is to use three-point and four-point correlation functions. An alternative approach, requiring only the computation of two-point correlation functions is to use the Feynman-Hellmann theorem. In this talk we develop this method up to second order in perturbation theory, in a context appropriate for lattice QCD. This encompasses the Compton Amplitude (which forms the basis for deep inelastic scattering) and hadron scattering. Some numerical results are presented showing results indicating what this approach might achieve.

• Extrapolating jet radiation with autoregressive transformers

  Anja Butter, François Charton, Javier Mariño Villadamigo, Ayodele Ore, Tilman Plehn, Jonas Spinner

  SciPost Phys. 20, 004 (2026) · published 12 January 2026 | Toggle abstract · pdf

  Generative networks are an exciting tool for fast LHC event generation with fixed number of particles. Autoregressive transformers allow us to generate events containing variable numbers of particles, very much in line with the physics of QCD jet radiation, and offer the possibility to generalize to higher multiplicities. We show how transformers can learn a factorized likelihood for jet radiation and extrapolate in terms of the number of generated jets. For this extrapolation, bootstrapping training data and training with modifications of the likelihood loss can be used.

• ATLAS Results with Beauty Mesons

  Ann-Kathrin Perrevoort

  SciPost Phys. Proc. 8, 099 (2022) · published 13 July 2022 | Toggle abstract · pdf

  A broad range of measurements involving $B$ mesons are performed with the ATLAS experiment at the Large Hadron Collider, of which a selection is discussed in this note. This includes a measurement of the relative $B_c^\pm$ to $B^\pm$ production cross section in $pp$ collisions at a centre-of-mass energy $\sqrt{s}$ of 8 TeV, as well as the latest results on the branching ratios of the rare decays $B^0_s\to\mu^+\mu^-$ and $B^0\to\mu^+\mu^-$ using $pp$ collisions recorded at $\sqrt{s}=$ 7, 8 and 13 TeV. Furthermore, accurate measurements of mixing and CP violation in $B_s^0 \to J/\psi\, \phi$ decays are performed. The latest results on the CP violating phase $\phi_s$ and other parameters describing the decay obtained at $\sqrt{s}=$ 7, 8 and 13 TeV are reported.

• Pair production of charged IDM scalars at high energy CLIC

  Jan Klamka

  SciPost Phys. Proc. 8, 097 (2022) · published 13 July 2022 | Toggle abstract · pdf

  The Compact Linear Collider (CLIC) was proposed as the next energy-frontier infrastructure at CERN, to study e$^+$e$^-$ collisions at three centre-of-mass energy stages: 380 GeV, 1.5 TeV and 3 TeV. The main goal of its high-energy stages is to search for the new physics beyond the Standard Model (SM). The Inert Doublet Model (IDM) is one of the simplest SM extensions and introduces four new scalar particles: H$^\pm$, A and H; the lightest, H, is stable and hence a natural dark matter (DM) candidate. A set of benchmark points is considered, which are consistent with current theoretical and experimental constraints and promise detectable signals at future colliders. Prospects for observing pair-production of the IDM scalars at CLIC were previously studied using signatures with two leptons in the final state. In the current study, discovery reach for the IDM charged scalar pair-production is considered for the semi-leptonic final state at the two high-energy CLIC stages. Full simulation analysis, based on the current CLIC detector model, is presented for five selected IDM scenarios. Results are then extended to the larger set of benchmarks using the Delphes fast simulation framework. The CLIC detector model for Delphes has been modified to take pile-up contribution from the beam-induced $\gamma\gamma$ interactions into account, which is crucial for the presented analysis. Results of the study indicate that heavy, charged IDM scalars can be discovered at CLIC for most of the proposed benchmark scenarios, with very high statistical significance.

• Longitudinal double-spin asymmetries of inclusive jet and dijet production at STAR

  Maria Zurek

  SciPost Phys. Proc. 8, 086 (2022) · published 12 July 2022 | Toggle abstract · pdf

  At the STAR experiment, the gluon helicity distribution $\Delta g(x, Q^2)$ can be accessed through the double-spin asymmetries $A_{LL}$ of inclusive jet and dijet production in collisions of longitudinally polarized protons. These proceedings report on recently published results of $A_{LL}$ for inclusive jets and dijets at $\sqrt{s} = 200$~GeV and $\sqrt{s} = 510$ GeV in mid-pseudorapidity ($|\eta| < 1$) and preliminary results for dijets in intermediate pseudrapidity ($-0.8 < \eta < 1.8$). The mid-pseudorapidity jet and dijet measurements are sensitive to $\Delta g(x, Q^2)$ for gluon momentum fractions $x$ from $\simeq 0.5$ down to $\simeq 0.015$; the sensitivity region for dijets in intermediate pseudorapidity at 510 GeV extends to even lower $x$. The measurements are in good agreement with previous STAR results and recent theoretical evaluations of prior world data.