2019, Ahdida, C., Albanese, R. M., Alexandrov, A., Anokhina, A., Atkin, E., Dmitrenko, V., Etenko, A., Filippov, K., Gavrilov, G., Grachev, V., Kudenko, Y., Novikov, A., Polukhina, N., Samsonov, V., Shustov, A., Skorokhvatov, M., Smirnov, S., Teterin, P., Ulin, S., Uteshev, Z., Vlasik, K., Аткин, Эдуард Викторович, Дмитренко, Валерий Васильевич, Этенко, Александр Владимирович, Грачев, Виктор Михайлович, Куденко, Юрий Григорьевич, Полухина, Наталья Геннадьевна, Шустов, Александр Евгеньевич, Скорохватов, Михаил Дмитриевич, Смирнов, Сергей Юрьевич, Тетерин, Пётр Евгеньевич, Улин, Сергей Евгеньевич, Утешев, Зияэтдин Мухамедович, Власик, Константин Федорович

© 2019 CERN.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 (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.

2020, Ahdida, C., Akmete, A., Albanese, R., Alexandrov, A., Atkin, E., Dmitrenko, V., Etenko, A., Filippov, K., Gavrilov, G., Grachev, V., Kudenko, Y., Novikov, A., Polukhina, N., Samsonov, V., Shustov, A., Skorokhvatov, M., Smirnov, S., Teterin, P., Ulin, S., Uteshev, Z., Vlasik, K., Аткин, Эдуард Викторович, Дмитренко, Валерий Васильевич, Этенко, Александр Владимирович, Грачев, Виктор Михайлович, Куденко, Юрий Григорьевич, Полухина, Наталья Геннадьевна, Шустов, Александр Евгеньевич, Скорохватов, Михаил Дмитриевич, Смирнов, Сергей Юрьевич, Тетерин, Пётр Евгеньевич, Улин, Сергей Евгеньевич, Утешев, Зияэтдин Мухамедович, Власик, Константин Федорович

© 2020, CERN for the benefit of the SHiP collaboration.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 10 11 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.

2019, Ahdida, C., Albanese, R., Alexandrov, A., Anokhina, A., Atkin, E., Dmitrenko, V., Etenko, A., Filippov, K., Gavrilov, G., Grachev, V., Kudenko, Y., Novikov, A., Polukhina, N., Samsonov, V., Shustov, A., Skorokhvatov, M., Smirnov, S., Teterin, P., Ulin, S., Uteshev, Z., Vlasik, K., Аткин, Эдуард Викторович, Дмитренко, Валерий Васильевич, Этенко, Александр Владимирович, Грачев, Виктор Михайлович, Куденко, Юрий Григорьевич, Полухина, Наталья Геннадьевна, Шустов, Александр Евгеньевич, Скорохватов, Михаил Дмитриевич, Смирнов, Сергей Юрьевич, Тетерин, Пётр Евгеньевич, Улин, Сергей Евгеньевич, Утешев, Зияэтдин Мухамедович, Власик, Константин Федорович

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 O(10) GeV/c(2) 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.

2020, Ahdida, C., Albanese, R., Alexandrov, A., Anokhina, A., Atkin, E., Dmitrenko, V., Etenko, A., Filippov, K., Gavrilov, G., Grachev, V., Kudenko, Y., Novikov, A., Polukhina, N., Samsonov, V., Shustov, A., Skorokhvatov, M., Smirnov, S., Teterin, P., Ulin, S., Uteshev, Z., Vlasik, K., Аткин, Эдуард Викторович, Дмитренко, Валерий Васильевич, Этенко, Александр Владимирович, Грачев, Виктор Михайлович, Куденко, Юрий Григорьевич, Полухина, Наталья Геннадьевна, Шустов, Александр Евгеньевич, Скорохватов, Михаил Дмитриевич, Смирнов, Сергей Юрьевич, Тетерин, Пётр Евгеньевич, Улин, Сергей Евгеньевич, Утешев, Зияэтдин Мухамедович, Власик, Константин Федорович

© 2020 CERN. Published by IOP Publishing Ltd on behalf of Sissa Medialab. Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.The Search for Hidden Particles (SHiP) experiment proposal at CERN demands a dedicated dipole magnet for its scattering and neutrino detector. This requires a very large volume to be uniformly magnetized at B > 1.2 T, with constraints regarding the inner instrumented volume as well as the external region, where no massive structures are allowed and only an extremely low stray field is admitted. In this paper we report the main technical challenges and the relevant design options providing a comprehensive design for the magnet of the SHiP Scattering and Neutrino Detector.

2019, Ahdida, C., Albanese, R., Alexandrov, A., Anokhina, A., Atkin, E., Dmitrenko, V., Etenko, A., Filippov, K., Gavrilov, G., Grachev, V., Kudenko, Y., Novikov, A., Polukhina, N., Samsonov, V., Shustov, A., Skorokhvatov, M., Smirnov, S., Teterin, P., Ulin, S., Uteshev, Z., Vlasik, K., Аткин, Эдуард Викторович, Дмитренко, Валерий Васильевич, Этенко, Александр Владимирович, Грачев, Виктор Михайлович, Куденко, Юрий Григорьевич, Полухина, Наталья Геннадьевна, Шустов, Александр Евгеньевич, Скорохватов, Михаил Дмитриевич, Смирнов, Сергей Юрьевич, Тетерин, Пётр Евгеньевич, Улин, Сергей Евгеньевич, Утешев, Зияэтдин Мухамедович, Власик, Константин Федорович

Heavy Neutral Leptons (HNLs) are hypothetical particles predicted by many extensions of the Standard Model. These particles can, among other things, explain the origin of neutrino masses, generate the observed matter-antimatter asymmetry in the Universe and provide a dark matter candidate. The SHiP experiment will be able to search for HNLs produced in decays of heavy mesons and travelling distances ranging between O(50 m) and tens of kilometers before decaying. We present the sensitivity of the SHiP experiment to a number of HNL's benchmark models and provide a way to calculate the SHiP's sensitivity to HNLs for arbitrary patterns of flavour mixings. The corresponding tools and data files are also made publicly available.

2021, Ahdida, C., Akmete, A., Albanese, R., Alexandrov, A., Atkin, E., Dmitrenko, V., Etenko, A., Filippov, K., Grachev, V., Kudenko, Y., Novikov, A., Polukhina, N., Samsonov, V., Shustov, A., Skorokhvatov, M., Smirnov, S., Teterin, P., Ulin, S., Uteshev, Z., Vlasik, K., Аткин, Эдуард Викторович, Дмитренко, Валерий Васильевич, Этенко, Александр Владимирович, Грачев, Виктор Михайлович, Куденко, Юрий Григорьевич, Полухина, Наталья Геннадьевна, Шустов, Александр Евгеньевич, Скорохватов, Михаил Дмитриевич, Смирнов, Сергей Юрьевич, Тетерин, Пётр Евгеньевич, Улин, Сергей Евгеньевич, Утешев, Зияэтдин Мухамедович, Власик, Константин Федорович

© 2021, The Author(s).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 αD = 0.1 and mA′ = 3mχ, 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 · 1020 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. [Figure not available: see fulltext.]