Publications

Order by: publication date number of citations

• Pion electronic decay and lepton universality

  D. Počanić

  SciPost Phys. Proc. 5, 025 (2021) · published 6 September 2021 | Toggle abstract · pdf

  In common with a number of simple processes involving elementary particles, charged pion decays are profoundly shaped by applicable Standard Model (SM) symmetries and properties. Given the highly precise SM theoretical description, pion decays are used as selective probes of SM parameters, and of possible SM extensions. The PEN experiment at PSI is studying the π + → e + ν e (γ), or π_ e2(γ) decay. The primary goal is to reach the relative precision of 5 × 10 ^{−4} in Re/μ^π, the branching ratio for π_ e2(γ) decay. We review the PEN research program, its present status, and prospects.

• Intermittency analysis of charged hadrons generated in Pb-Pb collisions at $\sqrt{s_{NN}}$= 2.76 TeV and 5.02 TeV

  Salman Khurshid Malik, Ramni Gupta

  SciPost Phys. Proc. 15, 012 (2024) · published 2 April 2024 | Toggle abstract · pdf

  Local density fluctuations are expected to scale as a universal power-law when the system approaches critical point. Such power-law fluctuations are studied within the framework of intermittency through the measurement of normalized factorial moments in ($\eta$, $\phi$) phase space. Observations and results from the intermittency analysis performed for charged particles in Pb-Pb collisions using PYTHIA8/Angantyr at 2.76 TeV and 5.02 TeV are reported. We observe no scaling behaviour in the particle generation for any of the centrality studied in narrow p$_T$ bins. The scaling exponent $\nu$ shows no dependence on the centrality ranges.

• ISAI: Investigating Solar Axion by Iron-57

  Tomonori Ikeda, Toshihiro Fujii, Takeshi Go Tsuru, Yuki Amano, Kazuho Kayama, Masamune Matsuda, Hiromu Iwasaki, Mizuki Uenomachi, Kentaro Miuchi, Yoshiyuki Onuki, Yoshizumi Inoue, Akimichi Taketa

  SciPost Phys. Proc. 12, 041 (2023) · published 4 July 2023 | Toggle abstract · pdf

  The existence of the axion is a unique solution for the strong CP problem, and the axion is one of the most promising candidates of the dark matter. Investigating Solar Axion by Iron-57 (ISAI) is being prepared as a complemented table-top experiment to confirm the solar axion scenario. Probing an X-ray emission from the nuclear transitions associated with the axion-nucleon coupling is a leading approach. ISAI searches for the monochromatic 14.4 keV X-ray from the first excited state of $^{57}$Fe using a state-of-the-art pixelized silicon detector, dubbed XRPIX, under an extremely low-background environment. We highlight scientific objectives, experimental design and the latest status of ISAI.

• Coherent photoproduction of $J/\psi$ in nucleus-nucleus collisions \\in the color dipole approach- an update

  Agnieszka Łuszczak, Wolfgang Schäfer

  SciPost Phys. Proc. 8, 109 (2022) · published 13 July 2022 | Toggle abstract · pdf

  We discuss the role of $c \bar c g$-Fock states in the diffractive photoproduction of $J/\psi$-mesons. We build on our earlier description of the process in the color-dipole approach, where we took into account the rescattering of $c \bar c$ pairs using a Glauber-Gribov form of the dipole-nucleus amplitude. We compare the results of our calculations to recent data on the photoproduction of $J/\psi$ by the ALICE and LHCb collaborations.

• Searching for wave-like dark matter with QSHS

  Ian Bailey, Bhaswati Chakraborty, Gemma Chapman, Edward J. Daw, John Gallop, Gianluca Gregori, Edward Hardy, Ling Hao, Edward Laird, Peter Leek, John March-Russell, Phil Meeson, Seaárbhan Ó Peatáin, Yuri Pashkin, Mitchell G. Perry, Michele Piscitelli, Edward Romans, Subir Sarkar, Paul J. Smith, Ningqiang Song, Mahesh Soni, Boon K. Tan, Stephen West, Stafford Withington

  SciPost Phys. Proc. 12, 040 (2023) · published 4 July 2023 | Toggle abstract · pdf

  In 2021 the Quantum Sensors for the Hidden Sector (QSHS) collaboration was founded in the UK and received funding to develop and demonstrate quantum devices with the potential to detect hidden sector particles in the $\mu$eV to 100 $\mu$eV mass window. The collaboration has been developing a range of devices. It is building a high-field, low-temperature facility at the University of Sheffield to characterise and test the devices in a haloscope geometry. This paper introduces the collaboration's motivation, aims, and progress.

• Photon TMDs from uPDFevolv

  Hannes Jung, Sara Taheri Monfared, Thomas Wening

  SciPost Phys. Proc. 8, 132 (2022) · published 13 July 2022 | Toggle abstract · pdf

  We present photon TMDs generated using the Parton Branching Method with QED evolution. We discuss the TMD’s properties and compare it to the gluon TMD. Two sets of TMDs differing in their initial evolution scale and the choice of the renormalisation scale are defined and compared to each other.

• Measurement-induced entanglement phase transitions in variational quantum circuits

  Roeland Wiersema, Cunlu Zhou, Juan Felipe Carrasquilla, Yong Baek Kim

  SciPost Phys. 14, 147 (2023) · published 8 June 2023 | Toggle abstract · pdf

  Variational quantum algorithms (VQAs), which classically optimize a parametrized quantum circuit to solve a computational task, promise to advance our understanding of quantum many-body systems and improve machine learning algorithms using near-term quantum computers. Prominent challenges associated with this family of quantum-classical hybrid algorithms are the control of quantum entanglement and quantum gradients linked to their classical optimization. Known as the barren plateau phenomenon, these quantum gradients may rapidly vanish in the presence of volume-law entanglement growth, which poses a serious obstacle to the practical utility of VQAs. Inspired by recent studies of measurement-induced entanglement transition in random circuits, we investigate the entanglement transition in variational quantum circuits endowed with intermediate projective measurements. Considering the Hamiltonian Variational Ansatz (HVA) for the XXZ model and the Hardware Efficient Ansatz (HEA), we observe a measurement-induced entanglement transition from volume-law to area-law with increasing measurement rate. Moreover, we provide evidence that the transition belongs to the same universality class of random unitary circuits. Importantly, the transition coincides with a “landscape transition” from severe to mild/no barren plateaus in the classical optimization. Our work may provide an avenue for improving the trainability of quantum circuits by incorporating intermediate measurement protocols in currently available quantum hardware.

• Measurements of $t\overline{t}$ production cross-sections with the ATLAS experiment at the LHC

  Margherita Spalla

  SciPost Phys. Proc. 8, 112 (2022) · published 13 July 2022 | Toggle abstract · pdf

  Comprehensive measurements of differential cross-sections of top-quark-antiquark pair-production are presented. They are performed in the dilepton, lepton+jets and the all-hadronic channels, using $\sqrt{s}=13$ TeV data from the ATLAS detector at the LHC. Several setups of next-to-leading order and next-to-next-to-leading order generators are quantitatively compared to the measurements. In addition, total cross-section measurements using up to the full ATLAS Run 2 dataset are presented.

• Exact one-particle density matrix for SU(N) fermionic matter-waves in the strong repulsive limit

  Andreas Osterloh, Juan Polo, Wayne J. Chetcuti, Luigi Amico

  SciPost Phys. 15, 006 (2023) · published 11 July 2023 | Toggle abstract · pdf

  We consider a gas of repulsive $N$-component fermions confined in a ring-shaped potential, subjected to an effective magnetic field. For large repulsion strengths, we work out a Bethe ansatz scheme to compute the two-point correlation matrix and then the one-particle density matrix. Our results hold in the mesoscopic regime of finite but sufficiently large number of particles and system size that are not accessible by numerics. We access the momentum distribution of the system and analyse its specific dependence of interaction, magnetic field and number of components $N$. In the context of cold atoms, the exact computation of the correlation matrix to determine the interference patterns that are produced by releasing cold atoms from ring traps is carried out.

• GRAND: A Giant Radio Array for Neutrino Detection

  Charles Timmermans for the GRAND collaboration

  SciPost Phys. Proc. 1, 042 (2019) · published 21 February 2019 | Toggle abstract · pdf

  GRAND will be a distributed set of about 20 arrays of radio antennas, totalling 200,000 km2. We aim to study the ultra high energy universe through the detection of neutrinos, photons and cosmic rays at energies at the EeV scale. In addition GRAND will be used to study astronomical objects like FRBs and GRBs. We will describe the physics motivation, the detection strategy, the first stages of GRAND and the path to creating the complete setup.