Publications

Order by: publication date number of citations

• Performance versus resilience in modern quark-gluon tagging

  Anja Butter, Barry M. Dillon, Tilman Plehn, Lorenz Vogel

  SciPost Phys. Core 6, 085 (2023) · published 12 December 2023 | Toggle abstract · pdf

  Discriminating quark-like from gluon-like jets is, in many ways, a key challenge for many LHC analyses. First, we use a known difference in PYTHIA and HERWIG simulations to show how decorrelated taggers would break down when the most distinctive feature is aligned with theory uncertainties. We propose conditional training on interpolated samples, combined with a controlled Bayesian network, as a more resilient framework. The interpolation parameter can be used to optimize the training evaluated on a calibration dataset, and to test the stability of this optimization. The interpolated training might also be useful to track generalization errors when training networks on simulations.

  1 citation

• Measurement of Transverse Spin Dependent Azimuthal Correlations of Charged Pion(s) in $p^{\uparrow} p$ Collisions at $\sqrt s = 200$ GeV at STAR

  Babu R. Pokhrel

  SciPost Phys. Proc. 8, 047 (2022) · published 12 July 2022 | Toggle abstract · pdf

  At the leading twist, the transversity distribution function, $h^{q}_{1}(x)$, where $x$ is the longitudinal momentum fraction of the proton carried by quark $q$, encodes the transverse spin structure of the nucleon. Extraction of it is difficult because of its chiral-odd nature. In transversely polarized proton-proton collisions ($p^\uparrow p$), $h_{1}^{q}(x)$ can be coupled with another chiral-odd partner, a spin-dependent fragmentation function (FF). The resulting asymmetries in hadron(s) azimuthal correlations directly probe $h_{1}^{q}(x)$. We report the measurement of correlation asymmetries for charged pion(s) in $p^\uparrow p$, through the Collins and the Interference FF channel.

  1 citation

• Direct searches of dark matter with the SABRE South experiment

  Madeleine J. Zurowski on behalf of the SABRE South Collaboration

  SciPost Phys. Proc. 12, 029 (2023) · published 4 July 2023 | Toggle abstract · pdf

  The SABRE (Sodium-iodide with Active Background REjection) South experiment is a direct dark matter detector, made of radio-pure NaI(Tl) crystals surrounded by a liquid scintillator veto. The achievement of ultra-low background rate is essential to provide a model independent test of the signal observed by the DAMA/LIBRA experiment whose claim has not been verified yet. The SABRE South experiment will be located at the Stawell Underground Physics Laboratory (SUPL), Australia, the first deep underground laboratory in the Southern Hemisphere. The laboratory will not only house rare event physics searches but also measurement facilities to support low background physics experiments and applications like radiobiology and quantum computing. The SABRE South detector commissioning is expected to occur in 2023. This paper details the setup and projections for the experiment, and a brief description of the underground laboratory.

  1 citation

• Correlations among 3N observables

  Yuriy Volkotrub, Jacek Golak, Roman Skibiński, Kacper Topolnicki, Henryk Witała

  SciPost Phys. Proc. 3, 055 (2020) · published 27 February 2020 | Toggle abstract · pdf

  We use a correlation matrix of two-nucleon (2N) potential parameters to investigate correlations among three-nucleon (3N) observables for the elastic nucleon-deuteron (Nd) scattering process. We employ the up-to-date 2N semilocal momentum-space regularized chiral interactions and the phenomenological OPE-Gaussian potential and using the Faddeev formalism we calculate 3N observables and their correlations. As an example, we present the correlation between the differential cross section and the deuteron analyzing power T20.

  1 citation

• A simple theory for quantum quenches in the ANNNI model

  Jacob H. Robertson, Riccardo Senese, Fabian H. L. Essler

  SciPost Phys. 15, 032 (2023) · published 27 July 2023 | Toggle abstract · pdf

  In a recent numerical study by Haldar et al. [Phys. Rev. X 11, 031062] it was shown that signatures of proximate quantum critical points can be observed at early and intermediate times after certain quantum quenches. Said work focused mainly on the case of the axial next-nearest neighbour Ising (ANNNI) model. Here we construct a simple time-dependent mean-field theory that allows us to obtain a quantitatively accurate description of these quenches at short times, which for reasons we explain remains a fair approximation at late times (with some caveats). Our approach provides a simple framework for understanding the reported numerical results as well as fundamental limitations on detecting quantum critical points through quench dynamics. We moreover explain the origin of the peculiar oscillatory behaviour seen in various observables as arising from the formation of a long-lived bound state.

  1 citation

• Codebase release 2.0 for UFOManager

  Mark S. Neubauer, Avik Roy, Zijun Wang

  SciPost Phys. Codebases 13-r2.0 (2023) · published 9 June 2023 | Toggle abstract · src

  Research in the data-intensive discipline of high energy physics (HEP) often relies on domain-specific digital contents. Reproducibility of research relies on proper preservation of these digital objects. This paper reflects on the interpretation of principles of Findability, Accessibility, Interoperability, and Reusability (FAIR) in such context and demonstrates its implementation by describing the development of an end-to-end support infrastructure for preserving and accessing Universal FeynRules Output (UFO) models guided by the FAIR principles. UFO models are custom-made python libraries used by the HEP community for Monte Carlo simulation of collider physics events. Our framework provides simple but robust tools to preserve and access the UFO models and corresponding metadata in accordance with the FAIR principles.

  1 citation

• An Ising model on a 3D honeycomb zigzag-ladder lattice: a solution to the ground-state problem

  Yuriy I. Dublenych, Oleg A. Petrenko

  SciPost Phys. Core 5, 047 (2022) · published 30 September 2022 | Toggle abstract · pdf

  A complex, seven-parameter ground-state problem for an Ising model on a 3D honeycomb zigzag-ladder lattice, containing two types of magnetic sites, is considered in the presence of an external field using the method of basic rays and basic sets of cluster configurations. It is shown that the geometrical frustration due to the presence of triangle elements leads to the emergence of a large variety of magnetic phases, the majority of which are highly degenerate. The obtained theoretical results are used to elucidate the sequence of phase transitions in the family of rare-earth oxides with a honeycomb zigzag-ladder lattice. New phases predicted by our model and observed experimentally do not appear in previously considered simpler models for noninteracting zigzag-ladders.

  1 citation

• Non-parametric learning critical behavior in Ising partition functions: PCA entropy and intrinsic dimension

  Rajat K. Panda, Roberto Verdel, Alex Rodriguez, Hanlin Sun, Ginestra Bianconi, Marcello Dalmonte

  SciPost Phys. Core 6, 086 (2023) · published 14 December 2023 | Toggle abstract · pdf

  We provide and critically analyze a framework to learn critical behavior in classical partition functions through the application of non-parametric methods to data sets of thermal configurations. We illustrate our approach in phase transitions in 2D and 3D Ising models. First, we extend previous studies on the intrinsic dimension of 2D partition function data sets, by exploring the effect of volume in 3D Ising data. We find that as opposed to 2D systems for which this quantity has been successfully used in unsupervised characterizations of critical phenomena, in the 3D case its estimation is far more challenging. To circumvent this limitation, we then use the principal component analysis (PCA) entropy, a "Shannon entropy" of the normalized spectrum of the covariance matrix. We find a striking qualitative similarity to the thermodynamic entropy, which the PCA entropy approaches asymptotically. The latter allows us to extract-through a conventional finite-size scaling analysis with modest lattice sizes-the critical temperature with less than 1% error for both 2D and 3D models while being computationally efficient. The PCA entropy can readily be applied to characterize correlations and critical phenomena in a huge variety of many-body problems and suggests a (direct) link between easy-to-compute quantities and entropies.

  1 citation

• Magnetic properties of a multicomponent intermetallic compound Tb$_{0.25}$Dy$_{0.25}$Ho$_{0.25}$Er$_{0.25}$Al$_2$

  P. K. Jesla, Jeyaramane Arout Chelvane, R. Nirmala

  SciPost Phys. Proc. 11, 013 (2023) · published 6 June 2023 | Toggle abstract · pdf

  Polycrystalline multicomponent Laves phase rare earth intermetallic compound Tb$_{0.25}$ Dy$_{0.25}$Ho$_{0.25}$Er$_{0.25}$Al$_{2}$ has been synthesized by arc-melting and characterized by powder X-ray diffraction, magnetization and heat capacity measurements. The sample has MgCu$_2$-type cubic structure (space group Fd-3m) at 300 K. The compound Tb$_{0.25}$Dy$_{0.25}$Ho$_{0.25}$Er$_{0.25}$ Al$_{2}$ orders ferromagnetically at 50 K (T$_C$). This value is almost equal to the average of the ferromagnetic ordering temperatures of the individual RAl$_2$ (R = Tb, Dy, Ho and Er) compounds. Field dependence of magnetization below T$_C$ indicates soft-ferromagnetic nature. From the magnetization vs field data obtained near T$_C$ and the temperature dependence of heat capacity, low field magnetocaloric effect has been estimated.

  1 citation

• Floquet fractional Chern insulators and competing phases in twisted bilayer graphene

  Peng-Sheng Hu, Yi-Han Zhou, Zhao Liu

  SciPost Phys. 15, 148 (2023) · published 10 October 2023 | Toggle abstract · pdf

  We study the many-body physics in twisted bilayer graphene coupled to periodic driving of a circularly polarized light when electron-electron interactions are taken into account. In the limit of high driving frequency $\Omega$, we use Floquet theory to formulate the system by an effective static Hamiltonian truncated to the order of $\Omega^{-2}$, which consists of a single-electron part and the screened Coulomb interaction. We numerically simulate this effective Hamiltonian by extensive exact diagonalization in the parameter space spanned by the twist angle and the driving strength. Remarkably, in a wide region of the parameter space, we identify Floquet fractional Chern insulator states in the partially filled Floquet valence bands. We characterize these topologically ordered states by ground-state degeneracy, spectral flow, and entanglement spectrum. In regions of the parameter space where fractional Chern insulator states are absent, we find topologically trivial charge density waves and band-dispersion-induced Fermi liquids which strongly compete with fractional Chern insulator states.

  1 citation