Publications

Order by: publication date number of citations

• Sensitivity on the electromagnetic dipole moments of the tau-lepton at the CLIC

  Maria de los Ángeles Hernández-Ruíz, Ahmet A. Billur, Murat Köksal, Alejandro Gutiérrez-Rodríguez

  SciPost Phys. Proc. 1, 045 (2019) · published 22 February 2019 | Toggle abstract · pdf

  In this paper we established model independent bounds on the anomalous magnetic and electric dipole moments of the tau-lepton using the process $\gamma\gamma \to \tau^+\tau^-}$. We use data collected with the future $e^+ e^-$ linear collider such as the CLIC at $\sqrt{s}$ = 380, 1500, 3000 GeV, and we consider systematic uncertainties of $\delta_{sys}$ = 0$\%$, 3$\%$, 5$\%$. The theory predictions are a very good prospect for probing the dipole moments of the tau-lepton at the future $e^ + e^-$ linear collider at the $\gamma\gamma$ mode.

• Bayesian illumination: Inference and quality-diversity accelerate generative molecular models

  Jonas Verhellen

  SciPost Chem. 4, 001 (2025) · published 28 May 2025 | Toggle abstract · pdf

  In recent years, there have been considerable academic and industrial research efforts to develop novel generative models for high-performing, small molecules. Traditional, rules-based algorithms such as genetic algorithms have, however, been shown to rival deep learning approaches in terms of both efficiency and potency [Jensen, Chem. Sci., 2019, 12, 3567-3572]. In previous work, we showed that the addition of a quality-diversity archive to a genetic algorithm resolves stagnation issues and substantially increases search efficiency [Verhellen, Chem. Sci., 2020, 42, 11485-11491]. In this work, we expand on these insights and leverage the availability of bespoke kernels for small molecules [Griffiths, Adv. Neural. Inf. Process. Syst., 2024, 36] to integrate Bayesian optimisation into the quality-diversity process. This novel generative model, which we call Bayesian Illumination, produces a larger diversity of high-performing molecules than standard quality-diversity optimisation methods. In addition, we show that Bayesian Illumination further improves search efficiency compared to previous generative models for small molecules, including deep learning approaches, genetic algorithms, and standard quality-diversity methods.

• Light sterile neutrinos: a critical overview

  Ivan Esteban

  SciPost Phys. Proc. 1, 026 (2019) · published 20 February 2019 | Toggle abstract · pdf

  Light sterile neutrinos, first proposed after the results of the LSND experiment, have been a polemical topic for the last decades after seemingly contradictory data appeared from different experiments. In this overview, I review the experimental hints that point towards sterile neutrinos as well as their statistical compatibility. Even though the muon neutrino disappearance experiments strongly rule out vanilla sterile neutrinos, each oscillation channel remains internally mostly consistent. In any case, in the near future a series of independent and precise experiments should finally settle down this issue.

• Rényi complexity in mean-field disordered systems

  Nina Javerzat, Eric Bertin, Misaki Ozawa

  SciPost Phys. 18, 124 (2025) · published 10 April 2025 | Toggle abstract · pdf

  Configurational entropy, or complexity, plays a critical role in characterizing disordered systems such as glasses, yet its measurement often requires significant computational resources. Recently, Rényi entropy, a one-parameter generalization of Shannon entropy, has gained attention across various fields of physics due to its simpler functional form, making it more practical for measurements. In this paper, we compute the Rényi version of complexity for prototypical mean-field disordered models, including the random energy model, its generalization, referred to as the random free energy model, and the $p$-spin spherical model. We first demonstrate that the Rényi complexity with index $m$ is related to the free energy difference for a generalized annealed Franz-Parisi potential with $m$ clones. Detailed calculations show that for models having one-step replica symmetry breaking (RSB), the Rényi complexity vanishes at the Kauzmann transition temperature $T_K$, irrespective of $m>1$, while RSB solutions are required even in the liquid phase. This study strengthens the link between Rényi entropy and the physics of disordered systems and provides theoretical insights for its practical measurements.

• Athermal creep deformation of ultrastable amorphous solids

  Pinaki Chaudhuri, Ludovic Berthier, Misaki Ozawa

  SciPost Phys. 19, 092 (2025) · published 10 October 2025 | Toggle abstract · pdf

  We numerically investigate the athermal creep deformation of amorphous materials having a wide range of stability. The imposed shear stress serves as the control parameter, allowing us to examine the time-dependent transient response through both the macroscopic strain and microscopic observables. Least stable samples exhibit monotonicity in the transient strain rate versus time, while more stable samples display a pronounced non-monotonic S-shaped curve, corresponding to failure by sharp shear band formation. We identify a diverging timescale associated with the fluidization process and extract the corresponding critical exponents. Our results are compared with predictions from existing scaling theories relevant to soft matter systems. The numerical findings for stable, brittle-like materials represent a challenge for theoretical descriptions. We monitor the microscopic initiation of shear bands during creep responses. Our study encompasses creep deformation across a variety of materials ranging from ductile soft matter to brittle metallic and oxide glasses, all within the same numerical framework.

• Quark Sivers Function at Small-$x$: Leading contribution from the Spin-Dependent Odderon

  M. Gabriel Santiago

  SciPost Phys. Proc. 8, 027 (2022) · published 11 July 2022 | Toggle abstract · pdf

  We present the calculation of the leading contribution to the quark Sivers function at small-Bjorken $x$. This calculation uses the high energy scattering approximation and operator formalism developed by Kovchegov and Sievert to obtain a dominant contribution to the quark Sivers function coming from the spin-dependent odderon, in agreement with the results of Dong, Zhen, and Zhou. We then calculate this dominant contribution in the diquark model of the proton to obtain a small-$x$ estimate for the Sivers function.

• Status of the MUonE experiment

  Riccardo N. Pilato

  SciPost Phys. Proc. 16, 034 (2025) · published 15 July 2025 | Toggle abstract · pdf

  The latest measurement of the muon g-2, recently announced at Fermilab, exhibits a 4.2$\sigma$ discrepancy from the Standard Model prediction. The hadronic contribution $a_{\mu}^{HLO}$ represents the main source of uncertainty on the theoretical prediction. The MUonE experiment proposes a novel approach to determine $a_{\mu}^{HLO}$ by measuring the effective electromagnetic coupling in the space-like region, via $\mu - e$ elastic scattering. The measurement is performed by scattering a 160 GeV muon beam, available at CERN, on atomic electrons of a low-Z target. A Test run on a reduced detector is planned in 2022, to validate this proposal. The status of the experiment in view of the Test run is presented.

• ATLAS results on charmonium production

  Vato Kartvelishvili

  SciPost Phys. Proc. 8, 014 (2022) · published 11 July 2022 | Toggle abstract · pdf

  An overview is given of the results on charmonium production obtained by the ATLAS collaboration at the LHC. Recent preliminary measurements covering prompt and non-prompt production of $J/\psi$ and $\psi(2S)$ states in the range of high transverse momenta from 60 to 360~GeV are highlighted.

• Solar neutrino physics with Borexino

  Andrea Pocar, M. Agostini, K. Altenmüller, S. Appel, V. Atroshchenko, Z. Bagdasarian, D. Basilico, G. Bellini, J. Benziger, G. Bonfini, D. Bravo, B. Caccianiga, F. Calaprice, A. Caminata, L. Cappelli, S. Caprioli, M. Carlini, P. Cavalcante, F. Cavanna, A. Chepurnov, K. Choi, L. Collica, D. D’Angelo, S. Davini, A. Derbin, X. F. Ding, A. Di Ludovico, L. Di Noto, I. Drachnev, K. Fomenko, A. Formozov, D. Franco, F. Gabriele, C. Galbiati, M. Gschwender, C. Ghiano, M. Giammarchi, A. Goretti, M. Gromov, D. Guffanti, T. Houdy, E. Hungerford, Aldo Ianni, Andrea Ianni, A. Jany, D. Jeschke, S. Kumaran, V. Kobychev, G. Korga, T. Lachenmaier, M. Laubenstein, E. Litvinovich, P. Lombardi, L. Ludhova, G. Lukyanchenko, L. Lukyanchenko, I. Machulin, G. Manuzio, S. Marcocci, J. Maricic, J. Martyn, E. Meroni, M. Meyer, L. Miramonti, M. Misiaszek, V. Muratova, B. Neumair, M. Nieslony, L. Oberauer, V. Orekhov, F. Ortica, M. Pallavicini, L. Papp, Ö. Penek, L. Pietrofaccia, N. Pilipenko, A. Porcelli, G. Raikov, G. Ranucci, A. Razeto, A. Re, M. Redchuk, A. Romani, N. Rossi, S. Rottenanger, S. Schönert, D. Semenov, M. Skorokhvatov, O. Smirnov, A. Sotnikov, L. F. F. Stokes, Y. Suvorov , R. Tartaglia, G. Testera, J. Thurn, E. Unzhakov, A. Vishneva, R. B. Vogelaar, F. von Feilitzsch, S. Weinz, M. Wojcik, M. Wurm, O. Zaimidoroga, S. Zavatarelli, K. Zuber, G. Zuzel

  SciPost Phys. Proc. 1, 025 (2019) · published 20 February 2019 | Toggle abstract · pdf

  We present the most recent solar neutrino results from the Borexino experiment at the Gran Sasso underground laboratory. In particular, refined measurements of all neutrinos produced in the {\it pp} fusion chain have been made. It is the first time that the same detector measures the entire range of solar neutrinos at once. These new data weakly favor a high-metallicity Sun. Prospects for measuring CNO solar neutrinos are also discussed.

• Real-space spectral simulation of quantum spin models: Application to generalized Kitaev models

  Francisco M. O. Brito, Aires Ferreira

  SciPost Phys. Core 7, 006 (2024) · published 21 February 2024 | Toggle abstract · pdf

  The proliferation of quantum fluctuations and long-range entanglement presents an outstanding challenge for the numerical simulation of interacting spin systems with exotic ground states. Here, we present a toolset of Chebyshev polynomial-based iterative methods that provides a unified framework to study the thermodynamical properties, critical behavior and dynamics of frustrated quantum spin models with controlled accuracy. Similar to previous applications of the Chebyshev spectral methods to condensed matter systems, the algorithmic complexity scales linearly with the Hilbert space dimension and the Chebyshev truncation order. Using this approach, we study two paradigmatic quantum spin models on the honeycomb lattice: the Kitaev-Heisenberg (K-H) and the Kitaev-Ising (K-I) models. We start by applying the Chebyshev toolset to compute nearest-neighbor spin correlations, specific heat and entropy of the K-H model on a 24-spin cluster. Our results are benchmarked against exact diagonalization and a popular iterative method based on thermal pure quantum states. The transitions between a variety of magnetic phases, namely ferromagnetic, Néel, zigzag and stripy antiferromagnetic and quantum spin liquid phases are obtained accurately and efficiently. We also determine the temperature dependence of the spin correlations, over more than three decades in temperature, by means of a finite temperature Chebyshev polynomial method introduced here. Finally, we report novel dynamical signatures of the quantum phase transitions in the K-I model. Our findings suggest that the efficiency, versatility and low-temperature stability of the Chebyshev framework developed here could pave the way for previously unattainable studies of quantum spin models in two dimensions.