Physics reach of the XENON1T dark matter experiment

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

Abstract

The XENON1T experiment is currently in the commissioning phase at the LaboratoriNazionali del Gran Sasso, Italy. In this article we study the experiment's expectedsensitivity to the spin-independent WIMP-nucleon interaction cross section, based on MonteCarlo predictions of the electronic and nuclear recoil backgrounds.The total electronic recoil background in 1 tonne ducial volume and (1, 12) keV electronicrecoil equivalent energy region, before applying any selection to discriminate betweenelectronic and nuclear recoils, is (1:800:15)104 (kg daykeV)1, mainly due to the decayof 222Rn daughters inside the xenon target. The nuclear recoil background in the correspondingnuclear recoil equivalent energy region (4, 50) keV, is composed of (0:6 0:1) (t y)1from radiogenic neutrons, (1:8 0:3) 102 (t y)1 from coherent scattering of neutrinos,and less than 0:01 (t y)1 from muon-induced neutrons.The sensitivity of XENON1T is calculated with the Pro le Likelihood Ratio method,after converting the deposited energy of electronic and nuclear recoils into the scintillationand ionization signals seen in the detector. We take into account the systematic uncertaintieson the photon and electron emission model, and on the estimation of the backgrounds, treatedas nuisance parameters. The main contribution comes from the relative scintillation eciencyLe , which a ects both the signal from WIMPs and the nuclear recoil backgrounds. After a2 y measurement in 1 t ducial volume, the sensitivity reaches a minimum cross section of 1:6 1047 cm2 at m=50 GeV/c2.