Publications

Order by: publication date number of citations

• The mass of the $\pi^-$

  M. Daum, D. Gotta

  SciPost Phys. Proc. 5, 010 (2021) · published 6 September 2021 | Toggle abstract · pdf

  The most precise values of the mass of the negatively charged pion have been determined from several measurements of X-ray wavelengths for transitions in pionic atoms at PSI. The Particle Data Group gives the average $m_{\pi^-}= (139.570 61 \pm 0.000 24) MeV/c^2$.

  5 citations

• Magnetic properties of the putative higher-order topological insulator EuIn$_2$As$_2$

  Tomasz Toliński, Dariusz Kaczorowski

  SciPost Phys. Proc. 11, 005 (2023) · published 5 June 2023 | Toggle abstract · pdf

  In higher-order topological insulator (HOTI), a gap is preserved both for the bulk and the surface states, and only hinges or corners become gapless. Recently, it has been predicted that the antiferromagnetic compound EuIn$_2$As$_2$ can host both the HOTI and axion insulator features. Preliminary experimental confirmation of this finding was obtained using angle-resolved photoemission spectroscopy. The main objective of this work was to characterize the anisotropic magnetic properties of single-crystalline EuIn$_2$As$_2$. In addition, complementary studies on the transport properties, heat capacity, and magnetocaloric effect in this compound were performed.

  5 citations

• Measurement of Intermittency for Charged Particles in Au + Au Collisions at $\sqrt{s_\mathrm{NN}}$ = 7.7-200 GeV from STAR

  Jin Wu

  SciPost Phys. Proc. 10, 041 (2022) · published 11 August 2022 | Toggle abstract · pdf

  Local density fluctuations near the QCD critical point can be probed by intermittency analysis of scaled factorial moments in relativistic heavy-ion collisions. We report the first measurement of intermittency for charged particles in Au + Au collisions at $\sqrt{s_\mathrm{NN}}$ = 7.7-200 GeV from the STAR experiment at RHIC. We observe scaling behaviors in central Au + Au collisions, with the extracted scaling exponent decreasing from mid-central to the most central Au + Au collisions. Furthermore, the scaling exponent exhibits a non-monotonic energy dependence with a minimum around $\sqrt{s_\mathrm{NN}}$ = 20-30 GeV in central Au + Au collisions.

  4 citations

• Underground laboratories

  Aldo Ianni

  SciPost Phys. Proc. 12, 007 (2023) · published 3 July 2023 | Toggle abstract · pdf

  A brief review on underground laboratories at the time of IDM 2022 is reported. General characteristics of these research infrastructures are discussed and a few highlights from different laboratories are reported. The idea of networking between underground laboratories is discussed.

  4 citations

• The QCD Equation of State in Small Systems

  W. A. Horowitz, Alexander Rothkopf

  SciPost Phys. Proc. 10, 025 (2022) · published 11 August 2022 | Toggle abstract · pdf

  We present first results on finite system size corrections to the equation of state, trace anomaly, and speed of sound for two model systems: 1) free, massless scalar theory and 2) quenched QCD with periodic boundary conditions (PBC). We further present work-in-progress results for quenched QCD with Dirichlet boundary conditions.

  4 citations

• Two-parton scattering in the high-energy limit: climbing two- and three-Reggeon ladders

  G. Falcioni, E. Gardi, N. Maher, C. Milloy, L. Vernazza

  SciPost Phys. Proc. 7, 007 (2022) · published 20 June 2022 | Toggle abstract · pdf

  We review recent progress on the calculation of scattering amplitudes in the high-energy limit. We start by illustrating the shockwave formalism, which allows one to calculate amplitudes as iterated solutions of rapidity evolution equations. We then focus on our recent results regarding 2 -> 2 parton scattering. We present the calculation of the imaginary part of the amplitude, at next-to-leading logarithmic accuracy in the high-energy logarithms, formally to all orders, and in practice to 13 loops. We then discuss the computation of the real part of the amplitude at next-to-next-to-leading logarithmic accuracy and through four loops. Both computations are carried in full colour, and provide new insight into the analytic structure of scattering amplitudes and their infrared singularity structure.

  4 citations

• Exploring the unknown Lambda-neutron interaction

  Benjamin F. Gibson, Iraj. R. Afnan

  SciPost Phys. Proc. 3, 025 (2020) · published 25 February 2020 | Toggle abstract · pdf

  No published Λn scattering data exist. A relativistic heavy-ion experiment has suggested that a Λnn bound state was seen. However, several theoretical analyses have cast serious doubt on the bound-state assertion. Nevertheless, there could exist a three-body Λnn resonance. Such a resonance could be used to constrain the Λn interaction. We dis- cuss Λnn calculations using nn and Λn pairwise interactions of rank-one, separable form that fit effective range parameters of the nn system and those hypothesized for the as yet unobserved Λn system based upon four different ΛN potentials. The use of rank-one separable potentials allows one to analytically continue the Λnn Faddeev equations onto the second complex energy plane in search of resonance poles, by examining the eigenvalue spectrum of the kernel of the Faddeev equations. Although each of the potential models predicts a Λnn sub-threshold resonance pole, scaling of the Λn interaction by as little as ∼5% does produce a physical resonance. This suggests that one may use photo- (electro-)production of the Λnn system from tritium as a tool to examine the strength of the Λn interaction.

  4 citations

• The DarkSide-20k TPC and underground argon cryogenic system

  Thomas N. Thorpe on behalf of the DS-20k collaboration

  SciPost Phys. Proc. 12, 069 (2023) · published 5 July 2023 | Toggle abstract · pdf

  DarkSide-20k (DS-20k) will exploit the physical and chemical properties of liquid argon (LAr) housed within a large dual-phase time project chamber (TPC) in its direct search for dark matter. The TPC will utilize a compact, integrated design with many novel features to enable the 20t fiducial volume of underground argon. Underground Argon (UAr) is sourced from underground CO$_2$ wells and depleted in the radioactive isotope $^{39}$Ar, greatly enhancing the experimental sensitivity to dark matter interactions. Sourcing and transporting the $\mathcal{O}$(100t) of UAr for (DS-20k) is costly, and a dedicated single-closed-loop cryogenic system has been designed, constructed, and tested to handle the valuable UAr. We present an overview of the (DS-20k) TPC design and the first results from the UAr cryogenic system.

  4 citations

• Application of Lorentzian CFT Principal Series Representation to Near Forward Scattering

  Pulkit Agarwal, Richard C. Brower, Timothy G. Raben, Chung-I Tan

  SciPost Phys. Proc. 10, 026 (2022) · published 11 August 2022 | Toggle abstract · pdf

  We present a discussion on recent progress in high energy diffraction from the perspective of AdS/CFT, through which a unified treatment for both perturbative and nonperturbative Pomeron emerges. By working with Unitary Irreducible Representation of Conformal group, a frame is provided in extending AdS/CFT to both forward and nearforward scattering. We present an analysis involving an exact solution to conformal blocks in Minkowski CFT and discuss possible applications. Phenomenological applications can range from forward scattering to DIS/DVCS/TMD at LHC energies and beyond.

  4 citations

• From magnetic order to valence-change crossover in EuPd$_2$(Si$_{1-x}$Ge$_x$)$_2$ using He-gas pressure

  Bernd Wolf, Felix Spathelf, Jan Zimmermann, Theresa Lundbeck, Marius Peters, Kristin Kliemt, Cornelius Krellner, Michael Lang

  SciPost Phys. Proc. 11, 022 (2023) · published 19 June 2023 | Toggle abstract · pdf

  We present results of magnetic susceptibility and thermal expansion measurements performed on high-quality single crystals of EuPd$_2$(Si$_{1-x}$Ge$_x$)$_2$ for 0 $\leq x \leq$ 0.2 and temperatures 2 K $\leq T \leq$ 300 K. Data were taken at ambient pressure and finite He-gas pressure $p$ $\leq$ 0.5 GPa. For $x = 0$ and ambient pressure we observe a pronounced valence-change crossover centred around $T'_V$ $\approx$ 160 K with a non-magnetic ground state. This valence-change crossover is characterized by an extraordinarily strong pressure dependence of d$T'_V$ /d$p$ = (80 $\pm 10)$ K/GPa. We observe a shift of $T'_V$ to lower temperatures with increasing Ge-concentration, reaching $T'_V$ $\approx$ 90 K for $x = 0.1$, while still showing a non-magnetic ground state. Remarkably, on further increasing $x$ to 0.2 we find a stable Eu$^{(2+\delta)+}$ valence with long-range antiferromagnetic order below $T_N$ = (47.5 $\pm$ 0.1) K, reflecting a close competition between two energy scales in this system. In fact, by the application of hydrostatic pressure as small as 0.1 GPa, the ground state of this system can be changed from long-range antiferromagnetic order for $p$ $<$ 0.1 GPa to an intermediate-valence state for $p$ $\geq$ 0.1 GPa.

  4 citations