Publications

Order by: publication date number of citations

• NLO collinear factorization of large mass diphoton photoproduction amplitude

  Oskar Grocholski, Bernard Pire, Paweł Sznajder, Lech Szymanowski, Jakub Wagner

  SciPost Phys. Proc. 8, 078 (2022) · published 12 July 2022 | Toggle abstract · pdf

  We calculate large mass diphoton exclusive photoproduction in the framework of collinear QCD factorization at next to leading order in {\alpha}s and at leading twist. Collinear divergences of the coefficient function are absorbed by the evolution of the generalized parton distributions (GPDs). This result enlarges the existing factorization proofs to 2 -> 3 processes, opening new reactions to a trustable extraction of GPDs.

• On correlation functions in models related to the Temperley-Lieb algebra

  Kohei Fukai, Raphael Kleinemühl, Balázs Pozsgay, Eric Vernier

  SciPost Phys. 16, 003 (2024) · published 5 January 2024 | Toggle abstract · pdf

  We deal with quantum spin chains whose Hamiltonian arises from a representation of the Temperley-Lieb algebra, and we consider the mean values of those local operators which are generated by the Temperley-Lieb algebra. We present two key conjectures which relate these mean values to existing literature about factorized correlation functions in the XXZ spin chain. The first conjecture states that the finite volume mean values of the current and generalized current operators are given by the same simple formulas as in the case of the XXZ chain. The second conjecture states that the mean values of products of Temperley-Lieb generators can be factorized: they can expressed as sums of products of current mean values, such that the coefficients in the factorization depend neither on the eigenstate in question, nor on the selected representation of the algebra. The coefficients can be extracted from existing work on factorized correlation functions in the XXZ model. The conjectures should hold for all eigenstates that are non-degenerate with respect to the local charges of the models. We consider concrete representations, where we check the conjectures: the so-called golden chain, the $Q$-state Potts model, and the trace representation. We also explain how to derive the generalized current operators from concrete expressions for the local charges.

• Study of entanglement in symmetric multi-quDits systems through information diagrams

  Julio Guerrero, Antonio Sojo, Alberto Mayorgas, Manuel Calixto

  SciPost Phys. Proc. 14, 029 (2023) · published 24 November 2023 | Toggle abstract · pdf

  Along this paper, we analyze the entanglement properties of symmetric multi-quDits systems in a special type of states created from the generalization to U(D) of the usual spin coherent states. By means of parity operators, we define what we call multicomponent Schrödinger cat states as parity adapted coherent states. Introducing the tool of information diagrams, i.e. representations of pairs of entropy measures, we analyze the correlation structure of this type of states and their M-wise reduced density matrices.

• Line operators in 4d Chern-Simons theory and Cherkis bows

  Nafiz Ishtiaque, Yehao Zhou

  SciPost Phys. 16, 052 (2024) · published 22 February 2024 | Toggle abstract · pdf

  We show that the phase spaces of a large family of line operators in 4d Chern-Simons theory with GL$_n$ gauge group are given by Cherkis bow varieties with $n$ crosses. These line operators are characterized by Hanany-Witten type brane constructions involving D3, D5, and NS5 branes in an $\Omega$-background. Linking numbers of the five-branes and mass parameters for the D3 brane theories determine the phase spaces and in special cases they correspond to vacuum moduli spaces of 3d $\mathcal{N}=4$ quiver theories. Examples include line operators that conjecturally create T, Q, and L-operators in integrable spin chains.

• Spectral solutions for the Schrödinger equation with a regular singularity

  Pushkar Mohile, Ayaz Ahmed, T. R. Vishnu, Pichai Ramadevi

  SciPost Phys. Core 7, 041 (2024) · published 5 July 2024 | Toggle abstract · pdf

  We propose a modification in the Bethe-like ansatz to reproduce the hydrogen atom spectrum and the wave functions. Such a proposal provided a clue to attempt the exact quantization condition (EQC) for the quantum periods associated with potentials $V(x)$ which are of the form $(V(x) = |x| + a/|x| + b/|x|^2 )$. We validate the EQC proposal by showing that our computed Voros spectrum in the limit $a,b → 0$ is matching well with the true spectrum of the familiar $|x|$ potential. Thus we have given a route to obtain the spectral solution for the one dimensional Schrödinger equation involving potentials with regular singularity at the origin.

• Joule heating in bad and slow metals

  Paolo Glorioso, Sean A. Hartnoll

  SciPost Phys. 13, 095 (2022) · published 12 October 2022 | Toggle abstract · pdf

  Heat supplied to a metal is absorbed by the electrons and then transferred to the lattice. In conventional metals energy is released to the lattice by phonons emitted from the Lindhard continuum. However in a 'bad' metal, with short mean free path, the low energy Lindhard continuum is destroyed. Furthermore in a 'slow' metal, with Fermi velocity less than the sound velocity, particle-hole pairs are kinematically unable to emit phonons. To describe energy transfer to the lattice in these cases we obtain a general Kubo formula for the energy relaxation rate in terms of the electronic density spectral weight $\text{Im} \, G^R_{nn}(\omega_k,k)$ evaluated on the phonon dispersion $\omega_k$. We apply our Kubo formula to the high temperature Hubbard model, using recent data from quantum Monte Carlo and experiments in ultracold atoms to characterize $\text{Im} \, G^R_{nn}(\omega_k,k)$. We furthermore use recent data from electron energy-loss spectroscopy to estimate the energy relaxation rate of the cuprate strange metal to a high energy optical phonon. As a second, distinct, application of our formalism we consider 'slow' metals. These are defined to have Fermi velocity less than the sound velocity, so that particle-hole pairs are kinematically unable to emit phonons. We obtain an expression for the energy relaxation rate of a slow metal in terms of the optical conductivity.

• Photon-ALP oscillations at CTA energies

  M. Kachelriess, J. Tjemsland

  SciPost Phys. Proc. 12, 043 (2023) · published 4 July 2023 | Toggle abstract · pdf

  Axions and axion-like-particles (ALPs) are well motivated beyond the standard model particles that can explain a variety of unsolved problems in physics, such as the strong CP problem and the nature of dark matter. These particles are characterised by their two-photon coupling, which leads to so-called photon-ALP oscillation as photons propagate through an external magnetic field. Such oscillations lead to characteristic signatures in the energy spectrum of high-energy photons from astrophysical sources, allowing us to probe the existence of ALPs and possibly dark matter. We review the signatures from ALPs in photon spectra and discuss a new method that can be used to directly search for the energy dependence of the oscillations. The focus is on photons at TeV-energies relevant for the upcoming Cherenkov Telescope Array (CTA).

• Measurement of the spectral function for the $τ^-\to K^-K_Sν_τ$ decay in BABAR experiment

  Sergey I. Serednyakov on behalf of the BABAR collaboration

  SciPost Phys. Proc. 1, 046 (2019) · published 22 February 2019 | Toggle abstract · pdf

  The decay $\tau^{-}\to K^{-}K_S\nu_{\tau}$ has been studied using $430\times10^6$ $e^+e^-\to \tau^+\tau^-$ events produced at a center-of-mass energy around 10.6 GeV at the PEP-II collider and studied with the BABAR detector. The mass spectrum of the $K^{-}K_S$ system has been measured and the spectral function has been obtained. The measured branching fraction ${\cal B}(\tau^{-}\to K^{-}K_S\nu_{\tau}) = (0.739\pm 0.011(\rm stat.)\pm 0.020(\rm syst.))\times 10^{-3}$ is found to be in agreement with earlier measurements.

• Spin degrees of freedom incorporated in conformal group: Introduction of an intrinsic momentum operator

  Seiichi Kuwata

  SciPost Phys. Proc. 14, 034 (2023) · published 24 November 2023 | Toggle abstract · pdf

  Considering spin degrees of freedom incorporated in the conformal generators, we introduce an intrinsic momentum operator $\pi_\mu$, which is feasible for the Bhabha wave equation. If a physical state $\psi_{ph}$ for spin s is annihilated by the $\pi_\mu$, the degree of $\psi_{ph}$, deg $\psi_{ph}$, should equal twice the spin degrees of freedom, $2 ( 2 s + 1)$ for a massive particle, where the multiplicity $2$ indicates the chirality. The relation deg $\psi_{ph}$ = 2(2s+1) holds in the representation $R_5$ (s,s), irreducible representation of the Lorentz group in five dimensions.

• The ATLAS Tile Calorimeter performance and its upgrade towards the High Luminosity Large Hadron Collider

  Ryan Mckenzie

  SciPost Phys. Proc. 8, 171 (2022) · published 14 July 2022 | Toggle abstract · pdf

  The Tile Calorimeter (TileCal) is a sampling calorimeter that forms the central region of the hadronic calorimeter of the ATLAS experiment. This sub-detector is to undergo its Phase-II upgrade during long-shutdown 3, in the years from 2025 to mid 2027, in preparation for the start of operation of the High Luminosity Large Hadron Collider (HL-LHC) in 2027. In this proceeding, an overview of the TileCal HL-LHC on-detector electronics upgrade is provided. The detectors Run-II performance in the cases of EM scale calibration, calorimeter response, cell energy distribution and noise as well as a portion of the 2015-2018 Test-beam campaigns results are examined.