Dark Matter Search Results from the Complete Exposure of the PICO-60 C$_3$F$_8$ Bubble Chamber

11 Feb 2019  ·  C. Amole, M. Ardid, I. J. Arnquist, D. M. Asner, D. Baxter, E. Behnke, M. Bressler, B. Broerman, G. Cao, C. J. Chen, U. Chowdhury, K. Clark, J. I. Collar, P. S. Cooper, C. B. Coutu, C. Cowles, M. Crisler, G. Crowder, N. A. Cruz-Venegas, C. E. Dahl, M. Das, S. Fallows, J. Farine, I. Felis, R. Filgas, F. Girard, G. Giroux, J. Hall, C. Hardy, O. Harris, T. Hillier, E. W. Hoppe, C. M. Jackson, M. Jin, L. Klopfenstein, C. B. Krauss, M. Laurin, I. Lawson, A. Leblanc, I. Levine, C. Licciardi, W. H. Lippincott, B. Loer, F. Mamedov, P. Mitra, C. Moore, T. Nania, R. Neilson, A. J. Noble, P. Oedekerk, A. Ortega, M. -C. Piro, A. Plante, R. Podviyanuk, S. Priya, A. E. Robinson, S. Sahoo, O. Scallon, S. Seth, A. Sonnenschein, N. Starinski, I. Štekl, T. Sullivan, F. Tardif, E. Vázquez-Jáuregui, N. Walkowski, E. Weima, U. Wichoski, K. Wierman, Y. Yan, V. Zacek, J. Zhang ·

Final results are reported from operation of the PICO-60 C$_3$F$_8$ dark matter detector, a bubble chamber filled with 52 kg of C$_3$F$_8$ located in the SNOLAB underground laboratory. The chamber was operated at thermodynamic thresholds as low as 1.2 keV without loss of stability... A new blind 1404-kg-day exposure at 2.45 keV threshold was acquired with approximately the same expected total background rate as the previous 1167-kg-day exposure at 3.3 keV. This increased exposure is enabled in part by a new optical tracking analysis to better identify events near detector walls, permitting a larger fiducial volume. These results set the most stringent direct-detection constraint to date on the WIMP-proton spin-dependent cross section at 2.5 $\times$ 10$^{-41}$ cm$^2$ for a 25 GeV WIMP, and improve on previous PICO results for 3-5 GeV WIMPs by an order of magnitude. read more

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Cosmology and Nongalactic Astrophysics High Energy Physics - Experiment Instrumentation and Detectors