Publications

Order by: publication date number of citations

• Photoproduction of diffractive dijets in Pythia 8

  Ilkka Helenius

  SciPost Phys. Proc. 8, 145 (2022) · published 14 July 2022 | Toggle abstract · pdf

  The new framework for the simulations of hard diffractive events in photoproduction within Pythia 8 is presented. The model, originally introduced for proton-proton collisions, applies the dynamical rapidity gap survival probability based on the multiparton interaction model in Pythia. These additional interactions provide a natural explanation for the observed factorization-breaking effects in hard diffraction by filling up the rapidity gaps used to classify the events of diffractive origin. The generated cross sections are well in line with the existing data from HERA experiments and predictions for the future electron-ion collider are presented. In addition, also predictions for ultra-peripheral collisions at the LHC have been calculated where the factorization-breaking effects are found to be more pronounced.

• A model for $F_L$ structure function at low values of $Q^2$ and $x$ - revisited

  Barbara Badelek, Anna Stasto

  SciPost Phys. Proc. 8, 082 (2022) · published 12 July 2022 | Toggle abstract · pdf

  A reanalysis of the model for the longitudinal structure function $F_L (x,Q^2)$ at low $x$ and low $Q^2$ was undertaken, in view of the advent of the EIC. The model includes the kinematic constraint $F_L\sim Q^4$ as $Q^2\rightarrow$ 0. It is based on the photon-gluon fusion mechanism suitably extrapolated to the region of low $Q^2$. Revised model was critically updated, extended to the EIC kinematic region, and e.g. contains new parameterisations of the parton distribution functions.

• Linking ladder operators for the Rosen-Morse and Pöschl-Teller systems

  Simon Garneau-Desroches, Véronique Hussin

  SciPost Phys. Proc. 14, 026 (2023) · published 24 November 2023 | Toggle abstract · pdf

  An analysis of the realizations of the ladder operators for the Rosen-Morse and Pöschl-Teller quantum systems is carried out. The failure of the algebraic method of construction in the general Rosen-Morse case is exposed and explained. We present the reduction of a recently obtained set of $(2n ± 1)$-th-order Rosen-Morse ladder operators to the usual first-order realization for the Pöschl-Teller case known in the literature.

• Probing hadronic interactions with measurements from the Pierre Auger Observatory

  B. Andrada

  SciPost Phys. Proc. 10, 005 (2022) · published 10 August 2022 | Toggle abstract · pdf

  The Pierre Auger Observatory is the largest facility in the world to study ultra-high-energy cosmic rays. It has a hybrid detection technique that combines the observation of the longitudinal development of extensive air showers and the measurement of their particles at the ground. This capability has opened the possibility to probe hadronic interactions taking place at energies well beyond those accessible by human-made accelerators. In this report, we present a selection of the latest results on hadronic interactions with measurements from the Pierre Auger Observatory. These data span over three decades in energy, showing the tension between data from the muon component of air showers and predictions based on the most updated hadronic interaction models.

• Three-nucleon force effects in the FSI configuration of the d(n, nn)p breakup reaction

  Hiroyuki Kamada, Henryk Witała, Jacek Golak, Roman Skibiński

  SciPost Phys. Proc. 3, 046 (2020) · published 27 February 2020 | Toggle abstract · pdf

  We investigated three-nucleon (3N) force effects in the final state interaction (FSI) configuration of the d(n, nn)p breakup reaction at the incoming nucleon energy E n = 200 MeV. Although 3N force effects for the elastic nucleon-deuteron scattering cross section at comparable energies are located predominantly in the region of intermediate and backward angles, the corresponding 3N force effects for the integrated FSI configuration breakup cross section are found also at forward scattering angles.

• Topological states in double monolayer graphene

  Ying-Hai Wu

  SciPost Phys. 13, 094 (2022) · published 12 October 2022 | Toggle abstract · pdf

  Motivated by the experiments on double monolayer graphene that observe a variety of fractional quantum Hall states [Liu et al., Nat. Phys. 15, 893 (2019); Li et al., Nat. Phys. 15, 898 (2019)], we study the special setting in which two monolayers have different areas. It has not been considered before and allows us to construct a class of exotic topological states. The elementary excitations of these states do not carry fractional charges but obey fractional statistics. This is in sharp contrast to all previously studied cases, where the two properties are intimately connected and serve as hallmarks of fractional quantum Hall states. Numerical calculations are performed to demonstrate that some states can be realized with realistic parameters.

• The low-energy spectrum in DAMIC at SNOLAB

  Alvaro E. Chavarria

  SciPost Phys. Proc. 12, 011 (2023) · published 3 July 2023 | Toggle abstract · pdf

  The DAMIC experiment employs large-area, thick charge-coupled devices (CCDs) to search for the interactions of low-mass dark matter particles in the galactic halo with silicon atoms in the CCD target. From 2017 to 2019, DAMIC collected data with a seven-CCD array (40-gram target) installed in the SNOLAB underground laboratory. We report dark-matter search results, including a conspicuous excess of events above the background model below 200$V_{ee}$, whose origin remains unknown. We present details of the published spectral analysis, and update on the deployment of skipper CCDs to perform a more precise measurement by early 2023.

• Tapered amplifier laser with frequency-shifted feedback

  A. Bayerle, S. Tzanova, P. Vlaar, B. Pasquiou, F. Schreck

  SciPost Phys. 1, 002 (2016) · published 22 October 2016 | Toggle abstract · pdf

  We present a frequency-shifted feedback (FSF) laser based on a tapered amplifier. The laser operates as a coherent broadband source with up to 370GHz spectral width and 2.3us coherence time. If the FSF laser is seeded by a continuous-wave laser a frequency comb spanning the output spectrum appears in addition to the broadband emission. The laser has an output power of 280mW and a center wavelength of 780nm. The ease and flexibility of use of tapered amplifiers makes our FSF laser attractive for a wide range of applications, especially in metrology.

• Phenomenological study on correlation between flow harmonics and mean transverse momentum in nuclear collisions

  Chunjian Zhang, Jiangyong Jia, Shengli Huang

  SciPost Phys. Proc. 10, 009 (2022) · published 10 August 2022 | Toggle abstract · pdf

  To assess the properties of the quark-gluon plasma formed in nuclear collisions, the Pearson correlation coefficient between flow harmonics and mean transverse momentum, $\rho\left(v_{n}^{2},\left[p_{\mathrm{T}}\right]\right)$, reflecting the overlapped geometry of colliding atomic nuclei, is measured. $\rho\left(v_{2}^{2},\left[p_{\mathrm{T}}\right]\right)$ was found to be particularly sensitive to the quadrupole deformation of the nuclei. We study the influence of the nuclear quadrupole deformation on $\rho\left(v_{n}^{2},\left[p_{\mathrm{T}}\right]\right)$ in $\rm{Au+Au}$ and $\rm{U+U}$ collisions at RHIC energy using $\rm{AMPT}$ transport model, and show that the $\rho\left(v_{2}^{2},\left[p_{\mathrm{T}}\right]\right)$ is reduced by the prolate deformation $\beta_2$ and turns to change sign in ultra-central collisions (UCC).

• “Reborn in Guate”: Making Resource Frontiers in Asylum in Guatemala’s Northern Petén

  Julia Morris

  Mig. Pol. 3, 003 (2024) · published 12 August 2024 | Toggle abstract · pdf

  The last decade and a half have seen a dramatic increase in the outsourcing and offshoring of asylum processing and resettlement to countries in the Global South. This article advances a new theoretical framework to examine the surge in new asylum regimes worldwide. Drawing on ethnographic fieldwork in several externalised asylum sites and specifically in Guatemala, it looks at these recent developments through the lens of ‘resource frontiers.’ Merging critical political ecological approaches on resource frontiers with research on border externalisation, I argue that ‘asylum frontiers’ are the social spaces connected to the exploration and development of a resource sector that extracts value from people on the move. I centre my analysis on the US-driven development of an asylum regime in Guatemala’s northern Petén region. I consider the specificities of Guatemala’s emerging asylum frontier, detailing how this arrangement sits with the country’s own histories of asylum and enforced return. In doing so, I show how different political actors – migrants, Indigenous Mayan refugees, and deported Guatemalans – ‘live with’ these frontier economies.