Physics reach of the XENON1T dark matter experiment.
Authors: Aprile E. , Aalbers J. , Agostini F. , Alfonsi M. , Amaro F. D. , Anthony M. , Arazi L. , Arneodo F. , Balan C. , Barrow P. , Baudis L. , Bauermeister B. , Berger T. , Breur P. , Breskin A. , Brown A. , Brown E. , Bruenner S. , Bruno G. , Budnik R. , Bütikofer L. , Cardoso J.M.R. , Cervantes M. , Cichon D. , Coderre D. , Colijn A. P. , Conrad J. , Contreras H. , Cussonneau J. P. , Decowski M. P. , de Perio P. , Gangi P. Di , Giovanni A. Di , Duchovni E. , Fattori S. , Ferella A.D. , Fieguth A. , Franco D. , Fulgione W. , Galloway M. , Garbini M. , Geis C. , Goetzke L. W. , Greene Z. , Grignon C. , Gross E. , Hampel W. , Hasterok C. , Itay R. , Kaether F. , Kaminsky B. , Kessler G. , Kish A. , Landsman H. , Lang R. F. , Lellouch D. , Levinson L. , Calloch M. Le , Levy C. , Lindemann S. , Lindner M. , Lopes J.A.M. , Lyashenko A. , Macmullin S. , Manfredini A. , Undagoitia T. Marrodán , Masbou J. , Massoli F.V. , Mayani D. , Fernandez A.J. Melgarejo , Meng Y. , Messina M. , Micheneau K. , Miguez B. , Molinario A. , Murra M. , Naganoma J. , Oberlack U. , Orrigo S.E.A. , Pakarha P. , Pelssers B. , Persiani R. , Piastra F. , Pienaar J. , Plante G. , Priel N. , Rauch L. , Reichard S. , Reuter C. , Rizzo A. , Rosendahl S. , Rupp N. , Santos J.M.F. dos , Sartorelli G. , Scheibelhut M. , Schindler S. , Schreiner J. , Schumann M. , Lavina L. Scotto , Selvi M. , Shagin P. , Simgen H. , Stein A. , Thers D. , Tiseni A. , Trinchero G. , Tunnell C. , Sivers M. von , Wall R. , Wang H. , Weber M. , Wei Y. , Weinheimer C. , Wulf J. , Zhang Y. 
Published: April 2016

The XENON1T experiment is currently in the commissioning phase at the Laboratori Nazionali del Gran Sasso, Italy. In this article we study the experiment's expected sensitivity to the spin-independent WIMP-nucleon interaction cross section, based on Monte Carlo predictions of the electronic and nuclear recoil backgrounds.The total electronic recoil background in 1 tonne fiducial volume and (1, 12) keV electronic recoil equivalent energy region, before applying any selection to discriminate between electronic and nuclear recoils, is (1.80 ± 0.15) · 10−4(kg·day·keV)−1, mainly due to the decay of222Rn daughters inside the xenon target. The nuclear recoil background in the corresponding nuclear recoil equivalent energy region (4, 50) keV, is composed of (0.6 ± 0.1) (t·y)−1from radiogenic neutrons, (1.8 ± 0.3) · 10−2(t·y)−1from coherent scattering of neutrinos, and less than 0.01 (t·y)−1from muon-induced neutrons. The sensitivity of XENON1T is calculated with the Profile Likelihood Ratio method, after converting the deposited energy of electronic and nuclear recoils into the scintillation and ionization signals seen in the detector. We take into account the systematic uncertainties on the photon and electron emission model, and on the estimation of the backgrounds, treated as nuisance parameters. The main contribution comes from the relative scintillation efficiency ℒeff, which affects both the signal from WIMPs and the nuclear recoil backgrounds. After a 2 y measurement in 1 t fiducial volume, the sensitivity reaches a minimum cross section of 1.6 · 10−47cm2at mχ = 50 GeV/c2.