New experiment for WIMP direct search (NEWSdm)

Natalia Polukhina,Nikolai Starkov,V.E Volkova,Y.V Zhezher,V.A Rubakov,D.G Levkov,V.A Matveev

doi:10.1051/epjconf/201819102023

Abstract

Dark Matter (DM) search is one of the most significant tasks of modern physics. Direct DM searches are nowadays one of the most fervid research topics with many experimental efforts devoted to the search for nucleus recoils induced by the scattering of Weakly Interactive Massive Particles (WIMP). The new experiment NEWSdm (Nuclear Emulsions for WIMP Search - directional measurement) aimed at direct search for DM particles is based on the technologies of nuclear emulsions combining high spatial resolution and the possibility of creating large mass detectors. Emulsion detectors able to reconstruct the direction of the nuclei recoiling on the WIMP are opening a new frontier to possibly extend DM searches beyond the neutrino background. The detector concept foresees the use of a bulk of nuclear emulsion surrounded with a shield from environmental radioactivity, to be placed on an equatorial telescope in order to cancel out the effect of the Earth rotation keeping the detector at a fixed orientation toward the expected direction of galactic WIMPs. Exploiting directionality would also prove the galactic origin of DM with an unambiguous signal-to-background separation. The use in NEWSdm of fine-grained nuclear emulsions both as target and nanometric tracking device for directional DM searches gives a unique opportunity for a high-significance discovery of galactic DM.

Highlights

Compelling evidence for an abundant, non-baryonic, non-luminous dark matter component was accumulated over the past decades [1]
The origin of the dark matter (DM) annual modulation signature and of its peculiar features is due to the Earth motion with respect to the DM particles constituting the Galactic Dark Halo, so it is not related to terrestrial seasons
The speed of the Earth in the Solar System is anyway small compared to the speed of the Sun in the Milky Way, so the amplitude of the annual modulation is of the order of a few percent

Summary

Introduction

Compelling evidence for an abundant, non-baryonic, non-luminous dark matter component was accumulated over the past decades [1]. The NEWSdm project aims at the direct detection of dark matter candidates by measuring the direction of WIMP-induced nucleus recoils. For this challenge, the detector exploits nuclear emulsions of new generation with nanometric grains for an ultra-high spatial resolution. The detector is planned to be placed on a moving platform (fig.4), which will be oriented to the Cygnus constellation during the entire exposure time, so that the WIMPs will always arrive in the detector from one direction, while the directions to possible background sources will vary In this case, the anisotropy of the signal can be interpreted as presence of the "wind" of particles from the Cygnus constellation

Readout system

Conclusion and perspectives