Publications

Order by: publication date number of citations

• Lepton flavor violation at FCC-ee and CEPC

  Pankaj Munbodh

  SciPost Phys. Proc. 17, 006 (2025) · published 23 July 2025 | Toggle abstract · pdf

  Lepton flavor violating processes are highly suppressed in the Standard Model. Therefore, if observed, lepton flavor violation would be a clear indication of new physics beyond the Standard Model. We study the process $e^+e^-\to\tau\mu$ at tree-level in the Standard Model Effective Field Theory both on the $Z$-pole and at higher center-of-mass energies. We show that the constraints derived from the future circular $e^+e^-$ colliders FCC-ee and CEPC, are complementary to those obtained from low-energy tau decays at BaBar and Belle, as well as projections from Belle-II.

  1 citation

• Amplitude and colour evolution

  Simon Plätzer

  SciPost Phys. Proc. 15, 007 (2024) · published 2 April 2024 | Toggle abstract · pdf

  Colour evolution and parton branching at the amplitude level have become important theoretical frameworks to improve parton showers, and are algorithms in their own right: They complement shower development by resummation algorithms capable of including interference effects and subleading colour contributions at an unprecedented level. I summarize recent development in the field, focusing on soft gluon evolution, hadronization, and the CVolver framework.

  1 citation

• Asymptotics of Weil-Petersson volumes and two-dimensional quantum gravities

  Luca Griguolo, Jacopo Papalini, Lorenzo Russo, Domenico Seminara

  SciPost Phys. 17, 156 (2024) · published 6 December 2024 | Toggle abstract · pdf

  We propose a refined expression for the large genus asymptotics of the Weil-Petersson volumes of the moduli space of super-Riemann surfaces with an arbitrary number of boundaries. Our formula leverages the connection between JT supergravity and its matrix model definition, utilizing some basic tools of resurgence theory. The final result holds for arbitrary boundary lengths and preserves the polynomial structure of the super-volumes. As a byproduct we also obtain a prediction for the large genus asymptotics of generalized $\Theta$-class intersection numbers. We extend our proposal to the case of the quantum volumes relevant for the Virasoro minimal string/Liouville gravity. Performing the classical limit on the quantum volumes, we recover a formula for the ordinary Weil-Petersson building blocks of JT gravity.

  1 citation

• Universal aspects of high-temperature relaxation dynamics in random spin models

  Tian-Gang Zhou, Wei Zheng, Pengfei Zhang

  SciPost Phys. 18, 120 (2025) · published 8 April 2025 | Toggle abstract · pdf

  Universality is a crucial concept in modern physics, allowing us to capture the essential features of a system's behavior using a small set of parameters. In this work, we unveil universal spin relaxation dynamics in anisotropic random Heisenberg models with infinite-range interactions at high temperatures. Starting from a polarized state, the total magnetization can relax monotonically or decay with long-lived oscillations, determined by the sign of a universal single function $A=-\xi_1^2+\xi_2^2-4\xi_2\xi_3+\xi_3^2$. Here $(\xi_1,\xi_3,\xi_3)$ characterizes the anisotropy of the Heisenberg interaction. Furthermore, the oscillation shows up only for $A>0$, with frequency $\Omega \propto \sqrt{A}$. This result is derived from the Kadanoff-Baym equation under the melon diagram approximation, which is consistent with numerical solutions. Furthermore, we verify our theory and approximation using exact diagonalization, albeit for a small system size of $N=8$. Our study sheds light on the universal aspect of quantum many-body dynamics beyond low energy limit.

  1 citation

• BBBW on the spindle

  Antonio Amariti, Salvo Mancani, Davide Morgante, Nicolò Petri, Alessia Segati

  SciPost Phys. 17, 154 (2024) · published 5 December 2024 | Toggle abstract · pdf

  We study the spindle compactification of families of AdS$_5$ consistent truncations corresponding to M5 branes wrapped on complex curves in Calabi-Yau three-folds. From the AdS/CFT correspondence these models are dual to $\mathcal{N}=1$ SCFTs obtained by gluing of $T_N$ blocks. The truncations considered here have both vector and hyper multiplets and the analysis of the BPS equations on the spindle allows to extract the central charges. Such analysis gives also consistency conditions for the existence of the solutions. The solutions are then found both analytically and numerically for opportune choices of the charges for some sub-families of truncations. We then compare our results with the one expected from the field theory side, by integrating the anomaly polynomial.

  1 citation

• General simulation method for spontaneous parametric down- and parametric up-conversion experiments

  Felix Riexinger, Mirco Kutas, Björn Haase, Patricia Bickert, Daniel Molter, Michael Bortz, Georg von Freymann

  SciPost Phys. Core 6, 022 (2023) · published 29 March 2023 | Toggle abstract · pdf

  Spontaneous parametric down-conversion (SPDC) sources are an important technology for quantum sensing and imaging. We demonstrate a general simulation method, based on modeling from first principles, reproducing the spectrally and spatially resolved absolute counts of a SPDC experiment. By additionally simulating parametric up- and down-conversion processes with thermal photons as well as effects of the optical system we accomplish good agreement with the experimental results. This method is broadly applicable and allows for the separation of contributing processes, virtual characterization of SPDC sources, and enables the simulation of many quantum based applications.

  1 citation

• Neutrino phenomenology via Type-(I+II) seesaw in the $U(1)_{L_e-L_\mu}$ model

  Priya Mishra, Mitesh Kumar Behera, Papia Panda, Shivaramakrishna Singirala, Rukmani Mohanta

  SciPost Phys. Proc. 16, 023 (2025) · published 15 July 2025 | Toggle abstract · pdf

  We show how, $L_e-L_\mu$ gauged symmetry is used as the Standard Model (SM) extension with the type (I+II) seesaw mechanism for neutrino mass generation. The particle content of this model involves three extra right handed neutrinos, one scalar triplet and one singlet with the SM spectrum. We discuss about lepton flavour violating decays $\mu → e\gamma$, $\tau \to \mu \bar \mu\mu$ and anomalous magnetic moment of muon.

  1 citation

• Codebase release 0.5 for divERGe

  Jonas B. Profe, Dante M. Kennes, Lennart Klebl

  SciPost Phys. Codebases 26-r0.5 (2024) · published 8 February 2024 | Toggle abstract · src

  We present divERGe, an open source, high-performance C/C++/Python library for functional renormalization group (FRG) calculations on lattice fermions. The versatile model interface is tailored to real materials applications and seamlessly integrates with existing, standard tools from the ab-initio community. The code fully supports multi-site, multi-orbital, and non-SU(2) models in all of the three included FRG variants: TU$^2$FRG, N-patch FRG, and grid FRG. With this, the divERGe library paves the way for widespread application of FRG as a tool in the study of competing orders in quantum materials.

  1 citation

• B boson search at KLOE/KLOE-2

  Elena Perez del Rio

  SciPost Phys. Proc. 16, 013 (2025) · published 14 July 2025 | Toggle abstract · pdf

  Following the many contributions KLOE-2 has done to Dark Matter (DM) searches, an alternative model, where the Dark Force mediator is an hypothetical leptophobic B boson, in contra-position to the U boson or "dark photon", is investigated. The B boson couples mainly to quarks and it can be searched in the Phi decay to $\eta$-B where B will decay in $\pi^{0}$-$\gamma$. So far, investigation of the $\pi^{0}$-$\gamma$ invariant mass shows no clear structure belonging to the signal of the DM mediator, hence, an upper limit in the number of events at 90% with CLs the technique will be established for the decay.

  1 citation

• $μ$-$e$ conversion experiments at J-PARC

  Natsuki Teshima

  SciPost Phys. Proc. 1, 039 (2019) · published 21 February 2019 | Toggle abstract · pdf

  There are two plans of experiments to search for muon to electron ($\mu$-$e$) conversion at J-PARC, which are called DeeMe and COMET. The $\mu$-$e$ conversion is one of the charged lepton flavor violation processes. The processes are forbidden in the Standard Model, but some theories beyond the Standard Model predict relatively large branching ratios at orders of $10^{-12}$ to $10^{-17}$. DeeMe will be conducted with a sensitivity of $1\times10^{-13}$ using a carbon target for 1 year, and COMET will be done with that of $3\times10^{-15}$ in Phase-I. In this article, the current status of these two experiments will be presented.

  1 citation