#Zeplin iii code#
#Zeplin iii series#

These hypothetical elementary particles could be Weakly Interacting Massive Particles, or WIMPs, weighing as little as a few protons or as much as several heavy nuclei. It ruled out cross-sections for elastic scattering of WIMPs off nucleons above 3.9 × 10 −8 pb (3.9 × 10 −44 cm 2) from the two science runs conducted at Boulby (83 days in 2008 and 319 days in 2010/11).ĭirect dark matter search experiments look for extremely rare and very weak collisions expected to occur between the cold dark matter particles that are believed to permeate our galaxy and the nuclei of atoms in the active medium of a radiation detector. The ZEPLIN-III project was led by Imperial College London and also included the Rutherford Appleton Laboratory and the University of Edinburgh in the UK, as well as LIP-Coimbra in Portugal and ITEP-Moscow in Russia.

#Zeplin iii series#

This was the last in a series of xenon-based experiments in the ZEPLIN programme pursued originally by the UK Dark Matter Collaboration (UKDMC). It operated at the Boulby Underground Laboratory (North-East England, UK) in the period 2006–2011. The ZEPLIN-III dark matter experiment attempted to detect galactic WIMPs using a 12 kg liquid xenon target. The shielding was completed by a 20-cm thick lead castle. The gamma-rays from neutron capture were detected by 52 modules of plastic scintillator placed around the moderator. The detector was surrounded by Gd-loaded polypropylene to moderate and capture neutrons, a potential source of background. The lower chamber contained liquid nitrogen to provide cooling.

Furthermore, NEST addresses the question of the magnitude of the light and charge yields of nuclear recoils, including their electric field dependence, thereby shedding light on the possibility of detection or exclusion of a low-mass dark matter WIMP by liquid xenon detectors.ZEPLIN-III experiment: the WIMP detector, built mainly out of copper, included two chambers within a cryostat vessel: the upper one contained 12 kg of active liquid xenon an array of 31 photomultipliers operated immersed in the liquid to detect prompt scintillation as well as delayed electroluminescence from a thin gas layer above the liquid. All available liquid xenon data on NR and ER to date have been taken into consideration in arriving at the current models.

#Zeplin iii code#

We present here improvements to the ex-isting NEST models and updates to the code which make the package even more realistic and turn it into a more full-fledged Monte Carlo simulation. It is packaged as C++ code for Geant4 that implements said models, overriding the default model which does not account for certain complexities, such as the reduction in yields for nuclear recoils (NR) compared to electron recoils (ER). 1ĪBSTRACT: The Noble Element Simulation Technique (NEST) is an exhaustive collection of mod-els explaining both the scintillation light and ionization yields of noble elements as a function of particle type (nuclear recoil, electron recoil, alphas), electric field, and incident energy or energy loss (dE/dx). We also comment on the complementarity of this study to recent work investigating these same pairs at a √ s = 500 GeV linear collider. For observations in the indirect detection arena we discuss the sensitivity of these results to additional assumptions made about the cosmological density of neutralinos and the galactic halo profile. In the direct detection arena the ability to distinguish between models will be dependent on further progress in addressing uncertainty in nuclear matrix elements. Using slightly more optimistic assumptions about background rates increases this number to 186 of the 276 pairs. With extremely conservative physics assumptions and background estimates we find 101 of the 276 degenerate pairs can be distinguished. We focus attention on neutralino scattering experiments (direct detection of relic neutralinos) and observations of gamma-rays from relic neutralino annihilation (indirect detection experiments). Despite inherent uncertainties in such things as the local halo density model, or background rates from astrophysical sources, we find observations associated with stable relic neutralinos can be a surprisingly effective discriminant between candidate theories.

In particular we consider 276 pairs of models that give rise to nearly identical patterns of observables at hadron colliders. We investigate the utility of cosmological and astrophysical observations for distinguishing between supersymmetric theories.