Maximum Likelihood Analysis of Low Energy CDMS II Germanium Data
Abstract
We report on the results of a search for a Weakly Interacting Massive Particle (WIMP) signal in low-energy data of the Cryogenic Dark Matter Search (CDMS~II) experiment using a maximum likelihood analysis. A background model is constructed using GEANT4 to simulate the surface-event background from Pb decay-chain events, while using independent calibration data to model the gamma background. Fitting this background model to the data results in no statistically significant WIMP component. In addition, we perform fits using an analytic ad hoc background model proposed by Collar and Fields, who claimed to find a large excess of signal-like events in our data. We confirm the strong preference for a signal hypothesis in their analysis under these assumptions, but excesses are observed in both single- and multiple-scatter events, which implies the signal is not caused by WIMPs, but rather reflects the inadequacy of their background model.
Keywords
Cite
@article{arxiv.1410.1003,
title = {Maximum Likelihood Analysis of Low Energy CDMS II Germanium Data},
author = {SuperCDMS Collaboration and R. Agnese and A. J. Anderson and D. Balakishiyeva and R. Basu Thakur and D. A. Bauer and J. Billard and A. Borgland and M. A. Bowles and D. Brandt and P. L. Brink and R. Bunker and B. Cabrera and D. O. Caldwell and D. G. Cerdeno and H. Chagani and Y. Chen and J. Cooley and B. Cornell and C. H. Crewdson and P. Cushman and M. Daal and P. C. F. Di Stefano and T. Doughty and L. Esteban and S. Fallows and E. Figueroa-Feliciano and M. Fritts and G. L. Godfrey and S. R. Golwala and M. Graham and J. Hall and H. R. Harris and S. A. Hertel and T. Hofer and D. Holmgren and L. Hsu and M. E. Huber and A. Jastram and O. Kamaev and B. Kara and M. H. Kelsey and A. Kennedy and M. Kiveni and K. Koch and A. Leder and B. Loer and E. Lopez Asamar and R. Mahapatra and V. Mandic and C. Martinez and K. A. McCarthy and N. Mirabolfathi and R. A. Moffatt and D. C. Moore and R. H. Nelson and S. M. Oser and K. Page and W. A. Page and R. Partridge and M. Pepin and A. Phipps and K. Prasad and M. Pyle and H. Qiu and W. Rau and P. Redl and A. Reisetter and Y. Ricci and H. E. Rogers and T. Saab and B. Sadoulet and J. Sander and K. Schneck and R. W. Schnee and S. Scorza and B. Serfass and B. Shank and D. Speller and S. Upadhyayula and A. N. Villano and B. Welliver and D. H. Wright and S. Yellin and J. J. Yen and B. A. Young and J. Zhang},
journal= {arXiv preprint arXiv:1410.1003},
year = {2015}
}
Comments
12 pages, 12 figures, submitted to PRD