Speaker
Dr
Francisco Neves
(LIP - Laboratorio de Instrumentacao e Fisica Experimental de Particulas)
Description
The Large Underground Xenon (LUX) experiment operated at the Sanford
Underground Research Facility from 2013 to 2016. The detector was
instrumented as a dual-phase xenon time projection chamber (TPC),
providing energy measurement, position information in 3D, and single-scatter
event identification. After decommissioning the instrument, the collaboration
continues to exhaustively exploit the existing calibration and WIMP-search
data aiming for a better understanding of the Liquid Xenon (LXe) physics
and also to perform searches of dark matter candidates beyond the
standard WIMP paradigm.
For WIMPs, a profile likelihood analysis using a total exposure of
$129\,\text{kg.yr}$ (runs $3+4$) set a $90$% CL upper
limit on the spin-independent (SI) cross section of $1.1\times10^{-46}\,\text{cm}^{2}$
at $M_{WIMP}=50\,\text{GeV.c}^{-2}$. For spin-dependent (SD) interactions,
cross sections above $\sigma_{n}^{SD}=1.6\times10^{-41}\,\text{cm}^{-2}$
($\sigma_{p}^{SD}=5\times10^{-40}\,\text{cm}^{2}$) are also excluded
at $M_{WIMP}=35\,\text{GeV.c}^{-2}$ ($90$% CL).
For axion and axion-like particles, a double-sided profile likelihood
analysis using an exposure of $38.4\,\text{kg.yr}$ (run $3$ only)
excluded $g_{Ae}$ larger than $3.5\times10^{-12}$ ($90$% CL)
for solar axions. This limit on the coupling corresponds to an upper
limit on the axion mass of $0.12\,\text{eV.c}^{-2}$ or $36.6\,\text{eV.c}^{-2}$,
depending on the theoretical model assumed. For galactic axion-like
particles, values of $g_{Ae}$ larger than $4.2\times10^{-13}$ are
excluded for particle masses in the range $1-16\,\text{keV.c}^{-2}$.
These are the most stringent constraints to date for these interactions.
Besides detailing the calibrations and analysis leading to the LUX
results, we will also present the LUX-ZEPLIN (LZ) detector, a LXe
dark matter detector featuring more than $5\,\text{tons}$ of target
material in the fiducial region (from a total of $10\,\text{tons}$
of xenon). It will be installed at the same facility used by LUX.
With a projected exposure of $1000\,\text{days}$ (commissioning starts
in 2020), LZ aims to exclude the WIMP-neutron (-proton) SD cross-sections
down to $2.7\times10^{-43}\,\text{cm}^{2}$ ($8.1\times10^{-42}\,\text{cm}^{2}$)
for a $40\,\text{GeV.c}^{-2}$ WIMP. For the WIMP-nucleon SI interactions,
a best sensitivity of $1.6\times10^{-48}\,\text{cm}^{2}$ ($90$% CL,
$M_{WIMP}=40\,\text{GeV.c}^{-2}$) is expected. This represents a
factor of $10$ improvement when compared to the expected sensitivities
of currently running LXe dark matter experiments.
Primary author
Dr
Francisco Neves
(LIP - Laboratorio de Instrumentacao e Fisica Experimental de Particulas)
