The SHiP experiment at the proposed CERN SPS Beam Dump Facility

The Search for Hidden Particles (SHiP) Collaboration has proposed a general-purpose experimental facility operating in beam-dump mode at the CERN SPS accelerator to search for light, feebly interacting particles. In the baseline configuration, the SHiP experiment incorporates two complementary detectors. The upstream detector is designed for recoil signatures of light dark matter (LDM) scattering and for neutrino physics, in particular with tau neutrinos. It consists of a spectrometer magnet housing a layered detector system with high-density LDM/neutrino target plates, emulsion-film technology and electronic high-precision tracking. The total detector target mass amounts to about eight tonnes. The downstream detector system aims at measuring visible decays of feebly interacting particles to both fully reconstructed final states and to partially reconstructed final states with neutrinos, in a nearly background-free environment. The detector consists of a 50 m long decay volume under vacuum followed by a spectrometer and particle identification system with a rectangular acceptance of 5 m in width and 10 m in height. Using the high-intensity beam of 400 GeV protons, the experiment aims at profiting from the 4 x 10(19) protons per year that are currently unexploited at the SPS, over a period of 5-10 years. This allows probing dark photons, dark scalars and pseudo-scalars, and heavy neutral leptons with GeV-scale masses in the direct searches at sensitivities that largely exceed those of existing and projected experiments. The sensitivity to light dark matter through scattering reaches well below the dark matter relic density limits in the range from a few MeV/c(2) up to 100 MeV-scale masses, and it will be possible to study tau neutrino interactions with unprecedented statistics. This paper describes the SHiP experiment baseline setup and the detector systems, together with performance results from prototypes in test beams, as it was prepared for the 2020 Update of the European Strategy for Particle Physics. The expected detector performance from simulation is summarised at the end

The experimental facility for the Search for Hidden Particles at the CERN SPS

The International School for Advanced Studies (SISSA) logo The International School for Advanced Studies (SISSA) logo The following article is OPEN ACCESS The experimental facility for the Search for Hidden Particles at the CERN SPS C. Ahdida44, R. Albanese14,a, A. Alexandrov14, A. Anokhina39, S. Aoki18, G. Arduini44, E. Atkin38, N. Azorskiy29, J.J. Back54, A. Bagulya32Show full author list Published 25 March 2019 • © 2019 CERN Journal of Instrumentation, Volume 14, March 2019 Download Article PDF References Download PDF 543 Total downloads 7 7 total citations on Dimensions. Article has an altmetric score of 1 Turn on MathJax Share this article Share this content via email Share on Facebook Share on Twitter Share on Google+ Share on Mendeley Article information Abstract The Search for Hidden Particles (SHiP) Collaboration has shown that the CERN SPS accelerator with its 400 GeV/c proton beam offers a unique opportunity to explore the Hidden Sector [1–3]. The proposed experiment is an intensity frontier experiment which is capable of searching for hidden particles through both visible decays and through scattering signatures from recoil of electrons or nuclei. The high-intensity experimental facility developed by the SHiP Collaboration is based on a number of key features and developments which provide the possibility of probing a large part of the parameter space for a wide range of models with light long-lived super-weakly interacting particles with masses up to Script O(10) GeV/c2 in an environment of extremely clean background conditions. This paper describes the proposal for the experimental facility together with the most important feasibility studies. The paper focuses on the challenging new ideas behind the beam extraction and beam delivery, the proton beam dump, and the suppression of beam-induced background

Measurement of the muon flux from 400 GeV/c protons interacting in a thick molybdenum/tungsten target

The SHiP experiment is proposed to search for very weakly interacting particles beyond the Standard Model which are produced in a 400 GeV/c proton beam dump at the CERN SPS. About 1011 muons per spill will be produced in the dump. To design the experiment such that the muon-induced background is minimized, a precise knowledge of the muon spectrum is required. To validate the muon flux generated by our Pythia and GEANT4 based Monte Carlo simulation (FairShip), we have measured the muon flux emanating from a SHiP-like target at the SPS. This target, consisting of 13 interaction lengths of slabs of molybdenum and tungsten, followed by a 2.4 m iron hadron absorber was placed in the H4 400 GeV/c proton beam line. To identify muons and to measure the momentum spectrum, a spectrometer instrumented with drift tubes and a muon tagger were used. During a 3-week period a dataset for analysis corresponding to (3.27±0.07) × 1011 protons on target was recorded. This amounts to approximatively 1% of a SHiP spill

Fast simulation of muons produced at the SHiP experiment using generative adversarial networks

This paper presents a fast approach to simulating muons produced in interactions of the SPS proton beams with the target of the SHiP experiment. The SHiP experiment will be able to search for new long-lived particles produced in a 400 GeV/c SPS proton beam dump and which travel distances between fifty metres and tens of kilometers. The SHiP detector needs to operate under ultra-low background conditions and requires large simulated samples of muon induced background processes. Through the use of Generative Adversarial Networks it is possible to emulate the simulation of the interaction of 400 GeV/c proton beams with the SHiP target, an otherwise computationally intensive process. For the simulation requirements of the SHiP experiment, generative networks are capable of approximating the full simulation of the dense fixed target, offering a speed increase by a factor of Script O(106). To evaluate the performance of such an approach, comparisons of the distributions of reconstructed muon momenta in SHiP's spectrometer between samples using the full simulation and samples produced through generative models are presented. The methods discussed in this paper can be generalised and applied to modelling any non-discrete multi-dimensional distribution

Track reconstruction and matching between emulsion and silicon pixel detectors for the SHiP-charm experiment

In July 2018 an optimization run for the proposed charm cross section measurement for SHiP was performed at the CERN SPS. A heavy, moving target instrumented with nuclear emulsion films followed by a silicon pixel tracker was installed in front of the Goliath magnet at the H4 proton beam-line. Behind the magnet, scintillating-fibre, drift-tube and RPC detectors were placed. The purpose of this run was to validate the measurement's feasibility, to develop the required analysis tools and fine-tune the detector layout. In this paper, we present the track reconstruction in the pixel tracker and the track matching with the moving emulsion detector. The pixel detector performed as expected and it is shown that, after proper alignment, a vertex matching rate of 87% is achieved

Thermal seasons in Hornsund (SW Spitsbergen)

In the studies on climate and its changes in the polar regions it is essential to determine climatic seasons which can be based on thermal, circular and phenological criteria but also according to different types of weather. The aim of this research is to determine thermal seasons, to characterize their structure and general regularities, which may make the more detailed environmental monitoring of these areas possible. According to many authors, a climatic characterization of a given area should be presented through defining its seasonal structure. This article attempts to find natural thermal periods in the polar climate, which differ from the conventional, fixed monthly or quarterly periods: spring III-V, summer VI-VIII, autumn IX-XI, winter XII-II; often accepted by many scientists in order to make the characterization of the course of selected meteorological elements easier. The analysis of the seasonal structure of the climate of Hornsund is based on the data from the period of 1990-1999. The indices that characterize the initial and final dates, the overall duration of the thermal seasons, and estimation of the seasons? changeability in thermal terms have been taken into consideration. Calendar boundaries have been set according to the method proposed by Kosiba (1958), in which the date that begins the period of the domination of days with the daily average air temperature (Ti) typical for a given season is accepted as the season?s boundary. As the quite significant changeability of the daily average air temperature complicates the choice of initial and final dates of seasons, additional criteria are used: the number of days proper for thermal season (w), days warmer than w?days, days colder than w-days, the average air temperature and other. This study provides a division into four seasons according to Baranowski?s criteria (1986) accepted on the basis of an analysis of the annual course of air temperature in Hornsund, the accepted thermal criteria are as follows: spring -2.5°C = 2.5°C, autumn -2,5°C <= Ti <= 2.5°C, winter Ti <= -2,5°C. The characteristics of a vegetative period are also defined. Its duration in the polar regions is difficult to estimate. If we accept the most commonly used criterion of the stabilization of the daily average air temperature over +5°C, we will face the situation in which the vegetative period in the polar regions is either very short or does not occur at all. Phenological observations of Sorkappland - S Spitsbergen (Dubiel, 1988) made it possible to estimate a natural thermal threshold 0?C which begins the vegetative period. The development of most plants and their first flower buds occurs in average air temperature of approximately 0?C. Blooming and producing seeds, on the other hand, occur when the air temperature exceeds 2.5°C. Seasons (fig. 17), determined on the basis of daily average air temperatures, characterize and emphasize the changeability of thermal conditions and the specifics of the polar climate very well, what results in the conclusions enumerated below: - in the researched decade the initial and final dates and the overall duration of the thermal seasons are characterized by great changeability, - the most stable, with regard to the initial date, are spring and summer, - the most changeable, with regard to duration, are autumn and summer, - the most thermally stable season is summer. The least thermally stable season is autumn, - transitional seasons have a tendency to prolong: mainly autumn (the effect is that winter becomes shorter) and to a lesser extent spring. Winter and summer shorten, - the analysis of the line of this trend reveals that summer gets slightly colder. Spring and winter do not show any significant changes, - the most visible tendency is a downward tendency of autumn temperatures - the effect of the prolonged duration towards winter, - a vegetative period shows a tendency to begin later and to finish slightly earlier. The final date, however, does not reveal any significant tendency for changes

University of Wroclaw achievements in polar meteorology and climatology

W niniejszym artykule dokonano syntezy dorobku ośrodka wrocławskiego w meteorologii i klimatologii polarnej, wskazano też na momenty przełomowe ale też kryzysowe w tej 60-letniej historii. Efektem ostatnich lat jest aktywność badawcza, która ma cechy innowacji i zastosowania meteorologii/klimatologii na pograniczu dziedzin (glacjologia, geomorfologia, biologia, chemia atmosfery). Cechą charakterystyczną badań wrocławskich geografów nadal pozostaje duże zaangażowanie w trudnych i nowatorskich tematach. Wyniki badań mają często charakter interdyscyplinarny. Spoglądając na dorobek wrocławski i innych ośrodków naukowych powinniśmy mieć świadomość, że dopiero nowoczesność stosowanych metod pomiarowych i narzędzi analiz nada polskiej klimatologii polarnej odpowiednią wartość naukową w wymiarze europejskim.This paper summarizes the University of Wroclaw achievements in polar meteorology and climatology. An attempt was made to identify milestones but also critical points in the 60-year history. Resumed after years of absence activity seems to be innovative with applications in many scientific branches (glaciology, geomorphology, biology, chemistry of atmosphere). A feature of geographers from Wroclaw still is a strong commitment to challenging and innovative topics, with results which are often interdisciplinary. Looking at the achievements of Wroclaw and other polish research centers should be aware that only modern methods of measurement and analysis tools will give the Polish polar climatology adequate scientific value of a European dimension

High-resolution electrical resistivity tomography applied to patterned ground, Wedel Jarlsberg Land, south-west Spitsbergen

This article presents results of two-dimensional electrical resistivity tomography (ERT) applied to three types of patterned ground in Wedel-Jarlsberg Land (Svalbard), carried out in late July 2012. The structures investigated include sorted circles, non-sorted polygons and a net with sorted coarser material. ERT was used to recognize the internal ground structure, the shape of permafrost table below the active layer and the geometric relationships between permafrost, ground layering and surface patterns. Results of inversion modelling indicate that the permafrost table occurs at a depth of 0.5–1 m in a mountain valley and 1–2.5 m on raised marine terraces. The permafrost table was nearly planar beneath non-sorted deposits and wavy beneath sorted materials. The mutual relationships between the permafrost table and the shape of a stone circle are different from those typically presented in literature. Ground structure beneath the net with sorted coarser materials is complex as implied in convective models. In non-sorted polygons, the imaging failed to reveal vertical structures between them