We report on a search for Weakly Interacting Massive Particles ( WIMPs ) using 278.8 days of data collected with the XENON1T experiment at LNGS .
XENON1T utilizes a liquid xenon time projection chamber with a fiducial mass of ( 1.30 ~ { } \pm~ { } 0.01 ) t , resulting in a 1.0 t \times yr exposure .
The energy region of interest , [ 1.4 , 10.6 ] \mathrm { keV _ { ee } } ( [ 4.9 , 40.9 ] \mathrm { keV _ { nr } } ) , exhibits an ultra-low electron recoil background rate of ( 82 \substack { +5 \ -3 } \textrm { ~ { } ( sys ) } \pm 3 \textrm { ~ { } ( stat ) } ) events/ ( \mathrm { t } \times \mathrm { yr } \times \mathrm { keV _ { ee } } ) .
No significant excess over background is found and a profile likelihood analysis parameterized in spatial and energy dimensions excludes new parameter space for the WIMP-nucleon spin-independent elastic scatter cross-section for WIMP masses above 6 GeV/c ^ { 2 } , with a minimum of 4.1 \times 10 ^ { -47 } cm ^ { 2 } at 30 GeV/c ^ { 2 } and 90 % confidence level .