Publications

Order by: publication date number of citations

• Adiabatic and irreversible classical discrete time crystals

  Adrian Ernst, Anna M. E. B. Rossi, Thomas M. Fischer

  SciPost Phys. 13, 091 (2022) · published 11 October 2022 | Toggle abstract · pdf

  We simulate the dynamics of paramagnetic colloidal particles that are placed above a magnetic hexagonal pattern and exposed to an external field periodically changing its direction along a control loop. The conformation of three colloidal particles above one unit cell adiabatically responds with half the frequency of the external field creating a time crystal at arbitrary low frequency. The adiabatic time crystal occurs because of the non-trivial topology of the stationary manifold. When coupling colloidal particles in different unit cells, many body effects cause the formation of topologically isolated time crystals and dynamical phase transitions between different adiabatic reversible and non-adiabatic irreversible space-time-crystallographic arrangements.

• Comparison of $pp$ and $p \bar{p}$ differential elastic cross sections and observation of the exchange of a Colorless $C$-odd gluonic compound

  C. Royon

  SciPost Phys. Proc. 10, 023 (2022) · published 11 August 2022 | Toggle abstract · pdf

  We describe the discovery of the colorless $C$-odd gluonic compound, the odderon, by the D0 and TOTEM Collaborations by comparing elastic differential cross sections measured in $pp$ and $p \bar{p}$ interactions at high energies.

• Measuring the light meson nuclear modification factor in p-Pb collisions over an unprecedented $p_{\text{T}}$ range with ALICE

  Joshua König

  SciPost Phys. Proc. 8, 048 (2022) · published 12 July 2022 | Toggle abstract · pdf

  Differential invariant cross sections of light neutral mesons in p-Pb collisions at $\sqrt{s_{\text{NN}}}$ = 8.16 TeV and in pp collisions at $\sqrt{s}$ = 8 TeV have been measured up to very high transverse momentum ($p_{\text{T}}$). By combining independent reconstruction techniques available in ALICE using the EMCal and PHOS calorimeters as well as the central barrel tracking detectors, the combined spectra cover almost two orders of magnitude in $p_{\rm T}$ for the $\pi^{0}$ meson. The nuclear modification factor $R_{\text{pPb}}$ has been measured for the $\pi^{0}$ and $\eta$ mesons and is found to be consistent with NLO pQCD, CGC and energy loss calculations. Comparisons to the $R_{\text{pPb}}$ of $\pi^{0}$ measured in $\sqrt{s_{\text{NN}}}$ = 5.02 TeV hint at a stronger suppression at low $p_{\rm T}$ with increasing collision energy.

• The two critical temperatures conundrum in La$_{1.83}$Sr$_{0.17}$CuO$_4$

  Abhisek Samanta, Itay Mangel, Amit Keren, Daniel P. Arovas, Assa Auerbach

  SciPost Phys. 16, 148 (2024) · published 5 June 2024 | Toggle abstract · pdf

  The in-plane and out-of-plane superconducting stiffness of ${\rm La}^{\vphantom{\dagger}}_{1.83}{\rm Sr}^{\vphantom{\dagger}}_{0.17}{\rm CuO}^{\vphantom{\dagger}}_4$ rings appear to vanish at different transition temperatures, which contradicts thermodynamical expectation. In addition, we observe a surprisingly strong dependence of the out-of-plane stiffness transition on sample width. With evidence from Monte Carlo simulations, this effect is explained by very small ratio $\alpha$ of inter-plane over intra-plane Josephson couplings. For three dimensional rings of millimeter dimensions, a crossover from layered three dimensional to quasi one dimensional behavior occurs at temperatures near the thermodynamic transition temperature ${T_{\rm c}}$, and the out-of-plane stiffness appears to vanish below ${T_{\rm c}}$ by a temperature shift of order $\alpha L_a/{\xi^{\parallel}}$, where $L_a/{\xi^{\parallel}}$ is the sample's width over coherence length. Including the effects of layer-correlated disorder, the measured temperature shifts can be fit by a value of $\alpha=4.1× 10^{-5}$, near ${T_{\rm c}}$, which is significantly lower than its previously measured value near zero temperature.

• ATLAS Results with Beauty Mesons

  Ann-Kathrin Perrevoort

  SciPost Phys. Proc. 8, 099 (2022) · published 13 July 2022 | Toggle abstract · pdf

  A broad range of measurements involving $B$ mesons are performed with the ATLAS experiment at the Large Hadron Collider, of which a selection is discussed in this note. This includes a measurement of the relative $B_c^\pm$ to $B^\pm$ production cross section in $pp$ collisions at a centre-of-mass energy $\sqrt{s}$ of 8 TeV, as well as the latest results on the branching ratios of the rare decays $B^0_s\to\mu^+\mu^-$ and $B^0\to\mu^+\mu^-$ using $pp$ collisions recorded at $\sqrt{s}=$ 7, 8 and 13 TeV. Furthermore, accurate measurements of mixing and CP violation in $B_s^0 \to J/\psi\, \phi$ decays are performed. The latest results on the CP violating phase $\phi_s$ and other parameters describing the decay obtained at $\sqrt{s}=$ 7, 8 and 13 TeV are reported.

• WG2 Summary: Small-x, Diffraction and Vector Mesons

  Tolga Altinoluk, Marta Luszczak, Daniel Tapia Takaki

  SciPost Phys. Proc. 8, 110 (2022) · published 13 July 2022 | Toggle abstract · pdf

  Here we briefly summarize the contributions to Working Group 2: Small-x, Diffraction and Vector Mesons, at the DIS2021 Workshop.

• $e^+e^-$ hadronic cross-sections with SND detector at VEPP 2000

  T. V. Dimova, M. N. Achasov, A. Yu. Barnyakov, K. I. Beloborodov, A. V. Berdyugin, A. G. Bogdanchikov, A. A. Botov, V. P. Druzhinin, L. V. Kardapoltsev, A. G. Kharlamov, A. A. Korol, D. P. Kovrizhin, A. S. Kupich, N. A. Melnikova, A. E. Obrazovsky, E. V. Pakhtusova, K.V. Pugachev, S. I. Serednyakov, D. A. Shtol, Z. K. Silagadze, I. K. Surin, Yu. V. Usov, V. N. Zhabin

  SciPost Phys. Proc. 16, 014 (2025) · published 14 July 2025 | Toggle abstract · pdf

  Data with an integrated luminosity of about 370 pb$^{-1}$ have been collected with the SND detector at the VEPP-2000 $e^+e^-$ collider. Here we present recent results on $e^+e^-$ annihilation into hadrons below 2 GeV based on a part of these data. In particular, we discuss measurements of the $e^+e^-\to \pi^+\pi^-$, $e^+e^- \to n\bar{n}$, $e^+e^- \to p\bar{p}$, and $e^+e^-\to \pi^+\pi^-\pi^0\pi^0$ cross sections, and study of the processes $e^+e^-\to \pi^+\pi^-\pi^0$, $e^+e^-\to K^+K^-\pi^0$, $e^+e^- \to \eta\pi^0 \gamma$, and $e^+e^- \to \eta \eta \gamma$.

• Resonating valence bonds and spinon pairing in the Dicke model

  R. Ganesh, L. Theerthagiri, G. Baskaran

  SciPost Phys. 4, 044 (2018) · published 30 June 2018 | Toggle abstract · pdf

  Resonating valence bond (RVB) states are a class of entangled quantum many body wavefunctions with great significance in condensed matter physics. We propose a scheme to synthesize a family of RVB states using a cavity QED setup with two-level atoms (with states $\vert 0 \rangle$ and $\vert 1 \rangle$) coupled to a common photon mode. In the lossy cavity limit, starting with an initial state of $M$ atoms excited and $N$ atoms in the ground state, we show that this setup can be configured as a Stern Gerlach experiment. A measurement of photon emission collapses the wavefunction of atoms onto an RVB state composed of resonating long-ranged singlets of the form $\frac{1}{\sqrt{2}}[\vert 0 1 \rangle - \vert 1 0 \rangle]$. Each emitted photon reduces the number of singlets by unity, replacing it with a pair of lone spins or `spinons'. As spinons are formed coherently in pairs, they are analogous to Cooper pairs in a superconductor. To simulate pair fluctuations, we propose a protocol in which photons are allowed to escape the cavity undetected. This leads to a mixed quantum state with a fluctuating number of spinon pairs -- an inchoate superconductor. Remarkably, in the limit of large system sizes, this protocol reveals an underlying quantum phase transition. Upon tuning the initial spin polarization ($M-N$), the emission exhibits a continuous transition from a dark state to a bright state. This is reflected in the spinon pair number distribution which can be tuned from sub-poissonian to super-poissonian regimes. This opens an exciting route to simulate RVB states and superconductivity.

• Pair production of charged IDM scalars at high energy CLIC

  Jan Klamka

  SciPost Phys. Proc. 8, 097 (2022) · published 13 July 2022 | Toggle abstract · pdf

  The Compact Linear Collider (CLIC) was proposed as the next energy-frontier infrastructure at CERN, to study e$^+$e$^-$ collisions at three centre-of-mass energy stages: 380 GeV, 1.5 TeV and 3 TeV. The main goal of its high-energy stages is to search for the new physics beyond the Standard Model (SM). The Inert Doublet Model (IDM) is one of the simplest SM extensions and introduces four new scalar particles: H$^\pm$, A and H; the lightest, H, is stable and hence a natural dark matter (DM) candidate. A set of benchmark points is considered, which are consistent with current theoretical and experimental constraints and promise detectable signals at future colliders. Prospects for observing pair-production of the IDM scalars at CLIC were previously studied using signatures with two leptons in the final state. In the current study, discovery reach for the IDM charged scalar pair-production is considered for the semi-leptonic final state at the two high-energy CLIC stages. Full simulation analysis, based on the current CLIC detector model, is presented for five selected IDM scenarios. Results are then extended to the larger set of benchmarks using the Delphes fast simulation framework. The CLIC detector model for Delphes has been modified to take pile-up contribution from the beam-induced $\gamma\gamma$ interactions into account, which is crucial for the presented analysis. Results of the study indicate that heavy, charged IDM scalars can be discovered at CLIC for most of the proposed benchmark scenarios, with very high statistical significance.

• New $\tau$-based evaluation of the hadronic vacuum polarization contribution to the muon anomalous magnetic moment

  Jesús Alejandro Miranda Hernández, Pablo Roig Garcés

  SciPost Phys. Proc. 16, 032 (2025) · published 15 July 2025 | Toggle abstract · pdf

  We revisit the radiative corrections to the $\tau^-\to\pi^-\pi^0\nu_\tau(\gamma)$ decays using Resonance Chiral Theory for the structure-dependent part. This channel is the most important one to understand the hadronic vacuum polarization piece of the muon g-2, which dominates the uncertainty of its data-driven prediction in the Standard Model. Using our results, the discrepancy between theory and experiment for this observable is reduced to $\sim2.2\sigma$.