Publications

Order by: publication date number of citations

• On the interactions and equilibrium between Einstein-Maxwell-dilaton black holes

  Ulrich K. Beckering Vinckers, Tomás Ortín

  SciPost Phys. Core 8, 044 (2025) · published 17 June 2025 | Toggle abstract · pdf

  We study the interactions and the conditions for the equilibrium of forces between generic non-rotating black holes of the Einstein–Maxwell–dilaton (EMD) theory. We study known (and some new) solutions of the time-symmetric initial-data problem describing an arbitrary number of those black holes, some of them with primary scalar hair. We show how one can distinguish between initial data corresponding to dynamical situations in which the black holes (one or many) are not in equilibrium and initial data which are just constant-time slices of a static solution of the full equations of motion describing static black holes using (self-)interaction energies. For a single black hole, non-vanishing self-interaction energy is always related to primary scalar hair and to a dynamical black hole. Removing the self-interaction energies in multi-center solutions we get interaction energies related to the attractive and repulsive forces acting on the black holes. As shown by Brill and Lindquist, for widely separated black holes, these take the standard Newtonian and Coulombian forms plus an additional interaction term associated with the scalar charges which is attractive for like charges.

• Recent results on Central Exclusive Production with the STAR detector

  Rafal Sikora

  SciPost Phys. Proc. 8, 087 (2022) · published 13 July 2022 | Toggle abstract · pdf

  We present results on the Central Exclusive Production of charged particle pairs $h^{+}h^{-}$ ($h = \pi, K, p$), $pp\to p^\prime+h^{+}h^{-}+p^\prime$, obtained with the STAR experiment at RHIC in proton-proton collisions at a center-of-mass energy of $\sqrt{s} = 200$ GeV. All final-state particles were reconstructed, including forward-scattered protons detected in the Roman Pot system. As a result, the Double Pomeron Exchange (DPE) events were selected and the non-exclusive backgrounds were efficiently rejected. Differential fiducial cross sections were measured as functions of observables related to the central hadronic final state and to the forward-scattered protons. The measured cross sections were compared to phenomenological model predictions based on the DPE. We also present preliminary results on the measurement of the same physics process at higher collision energy $\sqrt{s} = 510$ GeV. The data demonstrate features similar to those observed at $\sqrt{s} = 200$ GeV.

• Extensions of realisations for low-dimensional Lie algebras

  Iryna Yehorchenko

  SciPost Phys. Proc. 14, 048 (2023) · published 24 November 2023 | Toggle abstract · pdf

  We find extensions of realisations of some low-dimensional Lie algebras, in particular, for the Poincaré algebra for one space dimension. Using inequivalent extensions, we performed comprehensive classification of relative differential invariants for these Lie algebras. We show difference between classification of extensions of realisations, and classification of nonlinear realisations of Lie algebras.

• A linear algebra-based approach to understanding the relation between the winding number and zero-energy edge states

  Chen-Shen Lee

  SciPost Phys. Core 7, 003 (2024) · published 30 January 2024 | Toggle abstract · pdf

  The one-to-one relation between the winding number and the number of robust zero-energy edge states, known as bulk-boundary correspondence, is a celebrated feature of 1$d$ systems with chiral symmetry. Although this property can be explained by the K-theory, the underlying mechanism remains elusive. Here, we demonstrate that, even without resorting to advanced mathematical techniques, one can prove this correspondence and clearly illustrate the mechanism using only Cauchy's integral and elementary algebra. Furthermore, our approach to proving bulk-boundary correspondence also provides clear insights into a kind of system that doesn't respect chiral symmetry but can have robust left or right zero-energy edge states. In such systems, one can still assign the winding number to characterize these zero-energy edge states.

• Measurement of charged-particle production in single diffractive proton-proton collisions with the STAR detector

  Leszek Adamczyk

  SciPost Phys. Proc. 8, 081 (2022) · published 12 July 2022 | Toggle abstract · pdf

  We present results on the inclusive and identified (pion, kaon, proton and their antiparticles) charged-particle production in single diffractive (SD) dissociation process in proton-proton collisions at $\sqrt{s}=200$ GeV with the STAR detector at RHIC. The forward-scattered proton is measured in the Roman Pot (RP) system, while the charged particle tracks are reconstructed in the STAR Time Projection Chamber. The proton-antiproton production asymmetry is measured to study the baryon number transfer over a large rapidity interval in SD process. In addition, $K/\pi$ ratio is measured, showing a larger strangeness production at $p_T>0.5$ GeV/$\mathit{c}$ compared to measurements in inclusive proton-proton collisions.

• DEASA studies and applications to space physics and muon tomography

  Sonali Bhatnagar

  SciPost Phys. Proc. 13, 023 (2023) · published 29 September 2023 | Toggle abstract · pdf

  The high energy cosmic rays entering the Earth’s atmosphere throw light upon many aspects of Astroparticle and Particle Physics. This work outlines investigative learning about these high energy primaries based on a mini array DEASA in Agra, India. DEASA (Dayalbagh Educational Air Shower Array) consists of eight plastic scintillators each with an area of 1 square meter. This array covers an area of 260 square meters and is the first array in the northern part of our country. A real-life application of these highly energetic particles has been to find the best material to protect the astronaut from them in form of galactic cosmic rays (GCR). Geant4 based hadronic binary model was used in simulation of phantom, vehicle, SEP (Solar Energetic Particles) and GCR shield. The SEP shielding material was fixed as water and GCR shield was varied among aluminum, Polystyrene and Polyethylene. The poly materials were found to be the best due to large amount of hydrogen (H) and low atomic number (Z). In this work the equivalent dose deposited in the phantom with Polystyrene material for GCR shield was calculated to be minimum (107 sievert) as compared to the other materials. In the second application, the high energy muons have been studied to image nuclear caskets through muon tomography. In this Monte Carlo based simulation, a dry cask container containing different number of the UO2 rods have been bombarded with definite energy muons to measure the muon scattering . The parameters computed in this work are energy loss, radiation length and scattering angle which can calibrate these containers for correct identification of nuclear wastage.

• Accurate surrogate amplitudes with calibrated uncertainties

  Henning Bahl, Nina Elmer, Luigi Favaro, Manuel Haußmann, Tilman Plehn, Ramon Winterhalder

  SciPost Phys. Core 8, 073 (2025) · published 24 October 2025 | Toggle abstract · pdf

  Neural networks for LHC physics have to be accurate, reliable, and controlled. Using neural surrogates for the prediction of loop amplitudes as a use case, we first show how activation functions are systematically tested with Kolmogorov-Arnold Networks. Then, we train neural surrogates to simultaneously predict the target amplitude and an uncertainty for the prediction. We disentangle systematic uncertainties, learned by a well-defined likelihood loss, from statistical uncertainties, which require the introduction of Bayesian neural networks or repulsive ensembles. We test the coverage of the learned uncertainties using pull distributions to quantify the calibration of cutting-edge neural surrogates.

• Measurements of jet substructure and jet fragmentation using the ATLAS detector

  Javier Llorente Merino

  SciPost Phys. Proc. 8, 080 (2022) · published 12 July 2022 | Toggle abstract · pdf

  Measurements of the internal properties of jets at the LHC interaction scale allow QCD to be studied in a new energy regime. In this talk, we discuss recent measurements of jet substructure and jet fragmentation, which were performed using data collected by the ATLAS experiment at a centre-of-mass energy of $\sqrt{s}=13$ TeV. The fragmentation properties of jets, such as the jet charge and summed fragmentation function, are measured using charged particles. A comprehensive suite of jet substructure observables is also measured for jets reconstructed with the soft-drop algorithm applied. In addition, a measurement of the Lund plane is performed using charged particles. All of the measurements are corrected for detector effects and are compared to the predictions of state-of-the-art Monte Carlo event generators.

• $\mathcal{O}(α_s^3)$ corrections to semileptonic $b \to c$ decays in the heavy daughter approximation

  Kay Schoenwald

  SciPost Phys. Proc. 7, 027 (2022) · published 21 June 2022 | Toggle abstract · pdf

  We present our recent calculation of the third order corrections to the semileptonic $b \to c$ and the muon decays. The calculation has been performed in an expansion around the limit $m_c \sim m_b$, but shows decent convergence even for $m_c=0$ from which the contribution to the muon decay can be extracted. For the semileptonic $b \to c$ decay we find large perturbative corrections in the on-shell scheme which can be significantly reduced by changing to the kinetic scheme for the bottom quark mass. These results are important input for the inclusive determination of $|V_{cb}|$ and the Fermi coupling constant $G_F$.

• Measurements of sub-jet fragmentation with ALICE

  James Mulligan

  SciPost Phys. Proc. 10, 020 (2022) · published 10 August 2022 | Toggle abstract · pdf

  High-energy jets offer rich opportunities to study quantum chromodynamics, from investigating the limits of perturbative calculability to constraining the emergent properties of the quark-gluon plasma (QGP). In these proceedings, we present new measurements of the fragmentation properties of jets. We report distributions of the sub-jet momentum fraction $z_r$ measured in pp and Pb-Pb collisions with ALICE at the Large Hadron Collider. These measurements serve as input to test the universality of jet fragmentation in the QGP, and offer a path to elucidate jet quenching effects in the large-$z$ region.