Publications

Order by: publication date number of citations

• Mergers as a probe of particle dark matter

  Anupam Ray

  SciPost Phys. Proc. 12, 056 (2023) · published 5 July 2023 | Toggle abstract · pdf

  Black holes below Chandrasekhar mass limit (1.4 $M_{\odot}$) can not be produced via any standard stellar evolution. Recently, gravitational wave experiments have also discovered unusually low mass black holes whose origin is yet to be known. We propose a simple yet novel formation mechanism of such low mass black holes. Non-annihilating particle dark matter, owing to their interaction with stellar nuclei, can gradually accumulate inside compact stars, and eventually swallows them to low mass black holes, ordinarily impermissible by the Chandrasekhar limit. We point out several avenues to test this proposal, concentrating on the cosmic evolution of the binary merger rates.

• The scattering and neutrino detector at the LHC

  Giovanni De Lellis

  SciPost Phys. Proc. 12, 051 (2023) · published 5 July 2023 | Toggle abstract · pdf

  SND@LHC, Scattering and Neutrino Detector at the LHC, is a compact experiment designed to perform measurements with neutrinos produced at the LHC in the unexplored pseudo-rapidity region of 7.2 < $\eta$ < 8.4, complementary to all the other experiments at the LHC. The experiment was approved in March 2021. It was constructed in about one year and it is now taking data during the Run 3 of the LHC. In this paper we review the detector concept, the physics case and the status of the data taking.

• SUSY-QCD corrections to squark annihilation into gluons and light quarks

  Luca Paolo Wiggering

  SciPost Phys. Proc. 12, 047 (2023) · published 4 July 2023 | Toggle abstract · pdf

  We calculate the full one-loop SUSY-QCD corrections to stop annihilation into gluons and light quarks including the Sommerfeld enhancement effect and discuss their impact on the neutralino relic density in the MSSM.

• Light thermal relics enabled by a second Higgs

  Johannes Herms, Sudip Jana, Vishnu P. K., Shaikh Saad

  SciPost Phys. Proc. 12, 046 (2023) · published 4 July 2023 | Toggle abstract · pdf

  Sub-GeV thermal relic dark matter typically requires the existence of a light mediator particle. We introduce the light two-Higgs-doublet portal, illustrated by a minimal UV-complete model for sub-GeV dark matter with kinematically forbidden annihilations into leptons. All new physics states in this scenario lie at or below the electroweak scale, affecting Higgs physics, the muon anomalous magnetic moment and potentially neutrino masses. Observation of radiative dark matter annihilation by future MeV gamma-ray telescopes would be key to unambiguously identify the scenario.

• Axion-like particle as cold dark matter via the misalignment mechanism with PQ symmetry unbroken during inflation

  Pawel Kozow, Marek Olechowski

  SciPost Phys. Proc. 12, 038 (2023) · published 4 July 2023 | Toggle abstract · pdf

  The QCD axion and axion-like particles (ALPs) are well motivated candidates for Cold Dark Matter (CDM). Such models may be divided into two classes depending on whether the associated Peccei-Quinn (PQ) symmetry is broken or not during inflation. The latter case is usually considered to be quite simple with relic density depending only on the corresponding decay constant and with no constraints from the known bounds on isocurvature perturbations. We will show that the situation is much more complicated. We will discuss conditions which should be fulfilled by ALP models with U(1) unbroken during inflation to be phenomenologically interesting.

• Probing ALPs at the LUXE experiment

  Federico Meloni on behalf of the LUXE collaboration

  SciPost Phys. Proc. 12, 037 (2023) · published 4 July 2023 | Toggle abstract · pdf

  The proposed LUXE experiment (LASER Und XFEL Experiment) at DESY, Hamburg, aims to probe QED in its non-perturbative regime. In order to do this, LUXE will study the interactions between 16.5 GeV electrons from the European XFEL and high-intensity laser pulses. This experiment also provides a unique opportunity to probe physics beyond the Standard Model: exploiting the large photon flux generated at LUXE, it is possible to design a dedicated detector to probe axion-like-particles up to a mass of 350 MeV and with photon coupling of $3 \cdot 10^{-6}$ GeV$^{-1}$. This reach is comparable to the projected sensitivity of experiments like FASER2 at the HL-LHC and NA62 operating in dump mode.

• Background suppression in the COSINUS experiment: Active muon veto and radiopure materials selection

  M. Stukel, G. Angloher, Mukund Raghunath Bharadwaj, I. Dafinei , N. Di Marco, L. Einfalt, F. Ferroni, S. Fichtinger, A. Filipponi, T. Frank, M. Friedl, A. Fuss , Z. Ge, M. Heikinheimo, K. Huitu, M. Kellermann, R. Maji, M. Mancuso, L. Pagnanini, F. Petricca, S. Pirro, F. Pröbst, G. Profeta, A. Puiu, F. Reindl, K. Schäffner, J. Schieck, D. Schmiedmayer, C. Schwertner, M. Stahlberg, A. Stendahl, F. Wagner, S. Yue, V. Zema, Y. Zhu

  SciPost Phys. Proc. 12, 032 (2023) · published 4 July 2023 | Toggle abstract · pdf

  For over twenty-five years the DAMA/LIBRA experiment has reported an annual modulation signal that is consistent with a dark matter explanation. This signal is, currently, in tension with the null results observed by other searches that utilize different target detectors. The COSINUS experiment will perform a model-independent cross-check of the DAMA/LIBRA result by using the same target material, NaI crystals, operated as scintillating calorimeters. By measuring both temperature and light the NaI crystals in COSINUS will be able to distinguish between electron and nuclear recoils on an event-by-event basis. However, background events induced by cosmic-rays, environmental radioactivity or the intrinsic contamination of the materials used in the crystal, shielding and infrastructure can pose an issue to any analysis and must be fully understood. We report on the status of the development of the simulation for an active water Cherenkov muon veto, as well as the results of the beginning radiogenic material screening.

• Probing gluon density fluctuations at large momentum transfer $|t|$ at HERA

  Arjun Kumar

  SciPost Phys. Proc. 8, 166 (2022) · published 14 July 2022 | Toggle abstract · pdf

  The information on the gluonic structure and its fluctuations is captured by the differential $|t|$ spectrum in diffractive events. The incoherent cross-section is sensitive to the fluctuations in the target wavefunction in such events. We investigate the incoherent $ep$ cross-section in $J/\psi$ photoproduction using the impact-parameter dependent dipole model. The spatial gluonic structure is modelled as hotspots of gluon density having substructure where this substructure is modelled as hotspots within hotspots. We find that three levels of the substructure provide a good description of all the data, available up to $|t|=30~$GeV$^2$. We investigate these fluctuations in both the saturated and non-saturated dipole models and compare our predictions with the HERA Data.

• Hadron Polarimetry for the Electron-Ion Collider

  A.S. Nunes, E.C. Aschenauer, O. Eyser, W. Schmidke

  SciPost Phys. Proc. 8, 163 (2022) · published 14 July 2022 | Toggle abstract · pdf

  The Electron-Ion Collider (EIC) will be the first collider to use both polarized electron beams and polarized proton and light ion beams. It will therefore offer unique opportunities to study the structure of nucleons and to answer fundamental questions in QCD. The uncertainties on the polarization measurement translate directly into the uncertainties of final physics observables. Hence, a precise measurement of the hadron beam polarization and a good control of systematic uncertainties are critical for the success of the spin program at the EIC. Contrary to the case of electron beam polarimetry, which uses physical processes derived from first principles that allow a high precision extraction of the electron beam polarization, for hadron beams no such process is available. The currently best used methods rely on the process of elastic scattering in the Coulomb-Nuclear Interference (CNI) region, for which there are only effective models available. The experience from RHIC, the only existing polarized proton collider, will be detailed and the challenges of the measurements at the EIC will be addressed. In particular, measurements of the present RHIC polarimeters and simulations of the future EIC polarimeters will be presented.

• Neutron production in ($\alpha$,n) reactions in SOURCES4

  Vitaly A. Kudryavtsev, Piotr Krawczun, Rayna Bocheva

  SciPost Phys. Proc. 12, 018 (2023) · published 3 July 2023 | Toggle abstract · pdf

  Neutrons produced in spontaneous fission and ($\alpha,n$) reactions can induce background events in underground experiments looking for rare processes. A number of computer codes are available to calculate cross-sections of ($\alpha,n$) reactions, branching ratios to various states and neutron yields. SOURCES4 code has been used in this work to calculate neutron yields and energy spectra with input cross-sections and branching ratios taken from experimental data and models from EMPIRE2.19/3.2.3 and TALYS1.9 codes. A comparison of SOURCES4 calculations with experimental data from alpha beams and radioactive decay chains is presented.