Publications

Order by: publication date number of citations

• Predictions for neutron stars from holographic nuclear matter

  Nicolas Kovensky, Aaron Poole, Andreas Schmitt

  SciPost Phys. Proc. 6, 019 (2022) · published 31 May 2022 | Toggle abstract · pdf

  We discuss masses, radii, and tidal deformabilities of neutron stars constructed from the holographic Witten-Sakai-Sugimoto model. Using the same model for crust and core of the star, we combine our theoretical results with the latest astrophysical data, thus deriving more stringent constraints than given by the data alone. For instance, our calculation predicts - independent of the model parameters - an upper limit for the maximal mass of the star of about 2.46 solar masses and a lower limit of the (dimensionless) tidal deformability of a 1.4-solar-mass star of about 277.

  5 citations

• MuSun - Muon Capture on the Deuteron

  P. Kammel on behalf of the MuSun collaboration

  SciPost Phys. Proc. 5, 018 (2021) · published 6 September 2021 | Toggle abstract · pdf

  The MuSun experiment is a precision measurement of the rate for nuclear muon capture on the deuteron, designed to resolve a long-standing disagreement between experiment and theory, and to determine an important low-energy constant relevant for a variety of weak and strong dynamics. The experiment is based on a novel active target method employing a pure deuterium cryogenic time-projection chamber. The data taking was completed in two main campaigns and the analysis is well advanced. The unique chal- lenges and corresponding strategy of the experiment as well as the status of the analysis are presented.

  5 citations

• The history of the muon (g-2) experiments

  B. Lee Roberts

  SciPost Phys. Proc. 1, 032 (2019) · published 20 February 2019 | Toggle abstract · pdf

  I discuss the history of the muon $(g-2)$ measurements, beginning with the Columbia-Nevis measurement that observed parity violation in muon decay, and also measured the muon $g$-factor for the first time, finding $g_\mu=2$. The theoretical (Standard Model) value contains contributions from quantum electrodynamics, the strong interaction through hadronic vacuum polarization and hadronic light-by-light loops, as well as the electroweak contributions from the $W$, $Z$ and Higgs bosons. The subsequent experiments, first at Nevis and then with increasing precision at CERN, measured the muon anomaly $a_\mu = (g_\mu-2)/2$ down to a precision of 7.3 parts per million (ppm) The Brookhaven National Laboratory experiment E821 increased the precision to 0.54 ppm, and observed for the first time the electroweak contributions. Interestingly, the value of $a_\mu$ measured at Brookhaven appears to be larger than the Standard Model value by greater than three standard deviations. A new experiment, Fermilab E989, aims to improve on the precision by a factor of four, to clarify whether this result is a harbinger of new physics entering through loops, or from some experimental, statistical or systematic issue.

  5 citations

• Hybrid high-energy/collinear factorization in a heavy-light dijets system reaction

  Andrèe Dafne Bolognino, Francesco Giovanni Celiberto, Michael Fucilla, Dmitry Yu. Ivanov, Alessandro Papa

  SciPost Phys. Proc. 8, 068 (2022) · published 12 July 2022 | Toggle abstract · pdf

  We propose the inclusive hadroproduction of a heavy-light dijet system, as a new channel for the investigation of high energy QCD. We build up a hybrid factorization that incorporates a partial next-to-leading BFKL resummation inside the standard collinear description of observables. We present a detailed analysis of different observables: cross-section summed over azimuthal angles and differential in rapidity and azimuthal distribution. The stability that these distributions show under higher-order corrections motivates our interest in future studies, doable at new generation colliding machines.

  5 citations

• Higher-order corrections to exclusive heavy vector meson production

  Tuomas Lappi, Heikki Mäntysaari, Jani Penttala

  SciPost Phys. Proc. 8, 133 (2022) · published 14 July 2022 | Toggle abstract · pdf

  We present results for higher-order corrections to exclusive $\mathrm{J}/\psi$ production. This includes the first relativistic correction of order $v^2$ in quark velocity, and next-to-leading order corrections in $\alpha_s$ for longitudinally polarized production. The relativistic corrections are found to be important for a good description of the HERA data, especially at small values of the photon virtuality. The next-to-leading order results for longitudinal production are evaluated numerically. We also demonstrate how the vector meson production provides complementary information to the structure functions for extracting the initial condition for the small-$x$ evolution of the dipole-proton scattering amplitude.

  5 citations

• Tau polarimetry in B meson decays

  Rodrigo Alonso, Jorge Martin Camalich, Susanne Westhoff

  SciPost Phys. Proc. 1, 012 (2019) · published 19 February 2019 | Toggle abstract · pdf

  This article summarizes recent developments in $B\to D^{(\ast)}\tau\nu$ decays. We explain how to extract the tau lepton's production properties from the kinematics of its decay products. The focus is on hadronic tau decays, which are most sensitive to the tau polarizations. We present new results for effects of new physics in tau polarization observables and quantify the observation prospects at BELLE II.

  5 citations

• The search for the neutron electric dipole moment at PSI

  Guillaume Pignol, Philipp Schmidt-Wellenburg

  SciPost Phys. Proc. 5, 027 (2021) · published 6 September 2021 | Toggle abstract · pdf

  The existence of a nonzero permanent electric dipole moment (EDM) of the neutron would reveal a new source of CP violation and shed light on the origin of the matter--antimatter asymmetry of the Universe. The sensitivity of current experiments using stored ultracold neutrons (UCN) probes new physics beyond the TeV scale. Using the UCN source at the Paul Scherrer Institut, the nEDM collaboration has performed the most sensitive measurement of the neutron EDM to date, still compatible with zero ($|d_n|<1.8\times 10^{-26} \, e {\rm cm}$, C.L.90%). A new experiment designed to improve the sensitivity by an order of magnitude, n2EDM, is currently in construction.

  4 citations

• Recent results of laser spectroscopy experiments of pionic helium atoms at PSI

  M. Hori, H. Aghai-Khozani, A. S\'ot\'er, A. Dax, D. Barna

  SciPost Phys. Proc. 5, 026 (2021) · published 6 September 2021 | Toggle abstract · pdf

  A review of a recent experiment carried out at PSI involving laser spectroscopy of metastable pionic helium ($\pi{\rm ^4He}^+\equiv\pi^{-}+{\rm ^4He}^{2+}+e^-$) atoms is presented. An infrared transition $(n,\ell)=(17,16)$$\rightarrow$$(17,15)$ at a resonance frequency of $\nu\approx 183760$ GHz was detected.

  4 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 $m_{\pi^-}= (139.570 61 \pm 0.000 24) MeV/c^2$.

  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