Showing papers by "R. Froeschl published in 2021"

Sensitivity of the SHiP experiment to dark photons decaying to a pair of charged particles

Abstract: Dark photons are hypothetical massive vector particles that could mix with ordinary photons. The simplest theoretical model is fully characterised by only two parameters: the mass of the dark photon m $$_{\gamma ^{\mathrm {D}}}$$ and its mixing parameter with the photon, $$\varepsilon $$ . The sensitivity of the SHiP detector is reviewed for dark photons in the mass range between 0.002 and 10 GeV. Different production mechanisms are simulated, with the dark photons decaying to pairs of visible fermions, including both leptons and quarks. Exclusion contours are presented and compared with those of past experiments. The SHiP detector is expected to have a unique sensitivity for m $$_{\gamma ^{\mathrm {D}}}$$ ranging between 0.8 and 3.3 $$^{+0.2}_{-0.5}$$ GeV, and $$\varepsilon ^2$$ ranging between $$10^{-11}$$ and $$10^{-17}$$ .

Sensitivity of the SHiP experiment to light dark matter

Abstract: Dark matter is a well-established theoretical addition to the Standard Model supported by many observations in modern astrophysics and cosmology. In this context, the existence of weakly interacting massive particles represents an appealing solution to the observed thermal relic in the Universe. Indeed, a large experimental campaign is ongoing for the detection of such particles in the sub-GeV mass range. Adopting the benchmark scenario for light dark matter particles produced in the decay of a dark photon, with $\alpha_D=0.1$ and $m_{A'}=3m_{\chi}$, we study the potential of the SHiP experiment to detect such elusive particles through its Scattering and Neutrino detector (SND). In its 5-years run, corresponding to $2\cdot 10^{20}$ protons on target from the CERN SPS, we find that SHiP will improve the current limits in the mass range for the dark matter from about 1 MeV to 300 MeV. In particular, we show that SHiP will probe the thermal target for Majorana candidates in most of this mass window and even reach the Pseudo-Dirac thermal relic.

Measurements of secondary-particle emissions from copper target bombarded with 24-GeV/c protons

Abstract: To devise an activation technique for characterizing mixed radiation fields, secondary particles from a copper target irradiated by 24 GeV/c protons were measured at the CERN High-energy AcceleRator Mixed field facility (CHARM). Activation detector sets consisting of aluminum, niobium, indium, and bismuth, were placed at 30 cm from the target at angles of 15° to 160° with respect to the beam axis. The nuclides generated in these detectors due to irradiation by secondary particles were analyzed by γ -ray spectrometry, and the angular distributions of the production rates were obtained. The results of Monte Carlo calculations using FLUKA code was compared with the experimental results. The calculated results well agreed with the measured data at all angles. The influence of competitive reactions on the measured data were also evaluated by FLUKA. The following nuclear reactions, with low affectivity by competitive reactions, were identified as promising tools for characterizing mixed radiation fields: the 115In( n , n ′ ) 115 m In reaction for detecting neutrons emitted by the evaporation process, the 93Nb( γ , n ) 92 m Nb reaction for verifying the photon distribution generated by neutral-pion decay ( π 0 → 2 γ ), and the 209Bi( p , 4 n )206Po reaction, which detects secondary protons.

Measurements and Monte Carlo simulations of high-energy neutron streaming through the access maze using activation detectors at 24 GeV/c proton beam facility of CERN/CHARM

Abstract: A measurement of high-energy neutron streaming was performed through a maze at the CERN (Conseil Europeen pour la Recherche Nucleaire) High-energy AcceleRator Mixed-field (CHARM) facility. The prot...

Energy spectra of neutrons penetrating concrete and steel shielding blocks from 24 GeV/c protons incident on thick copper target

Abstract: In this study, experimental measurements were performed on the spectra of neutrons which penetrate concrete and steel of various thicknesses values when a proton beam of 24 GeV/c was incident on a copper target at the CHARM facility in the East Hall of the CERN Proton Synchrotron (PS) The thicknesses of concrete and steel ranged up to 360 cm and 80 cm, respectively. To measure the neutron spectra, an NE213 scintillator was positioned on the top roof of the shielding structure as the neutron detector. The light output distributions of the detector were converted into the neutron energy spectra using the unfolding method with a calculated response matrix after removing the γ -ray and charged particle events by pulse-shape discrimination and veto counter signals, respectively. The neutron spectra were in agreement with the results obtained using the Monte Carlo simulation code, PHITS, within a factor of 1.4 except for the case of steel 80 cm. The attenuation profiles for concrete and steel were consistent with previous foil activation results within the respective uncertainties.