Anthony Villano, Kitty Harris, Staci Brown
Neutron capture-induced nuclear recoils have emerged as an important tool for detector calibrations in direct dark matter detection and coherent elastic neutrino-nucleus scattering (CE$ν$NS). $\texttt{nrCascadeSim}$ is a command-line tool for generating simulation data for energy deposits resulting from neutron capture on pure materials. Presently, silicon, germanium, neon, and argon are supported. While the software was developed for solid state detector calibration, it can be used for any application which requires simulated neutron capture-induced nuclear recoil data.
Robert Agnese, Taylor Aralis, Tsuguo Aramaki, Isaac Arnquist, Elham Azadbakht, William Baker, Samir Banik, D'Ann Barker, Dan Bauer, Thomas Binder, Michael Bowles, Paul Brink, Ray Bunker, Blas Cabrera, Robert Calkins, Concetta Cartaro, David Cerdeno, Yen-Yung Chang, Jodi Cooley, Brett Cornell, Priscilla Cushman, Philippe Di Stefano, Todd Doughty, Eleanor Fascione, Tali Figueroa, Caleb Fink, Matt Fritts, Gilles Gerbier, Richard Germond, Muad Ghaith, Sunil Golwala, Rusty Harris, Ziqing Hong, Eric Hoppe, Lauren Hsu, Martin Huber, Vijay Iyer, Dan Jardin, Chitrasen Jena, Michael Kelsey, Allison Kennedy, Andrew Kubik, Noah Kurinsky, Richard Lawrence, Ben Loer, Elias Lopez-Asamar, Pat Lukens, Danika MacDonell, Rupak Mahapatra, Vuk Mandic, Nicholas Mast, Eric Miller, Nader Mirabolfathi, Bedangadas Mohanty, Jorge Morales, Jack Nelson, John Orrell, Scott Oser, William Page, Richard Partridge, Mark Pepin, Francisco Ponce, Sudip Poudel, Matt Pyle, Hang Qiu, Wolfgang Rau, Angela Reisetter, Tom Ren, Tyler Reynolds, Amy Roberts, Alan Robinson, Hannah Rogers, Tarek Saab, Bernard Sadoulet, Joel Sander, Andrew Scarff, Richard Schnee, Silvia Scorza, Kartik Senapati, Bruno Serfass, Danielle Speller, Matthew Stein, Joseph Street, Hirohisa Tanaka, David Toback, Ryan Underwood, Anthony Villano, Belina von Krosigk, Samuel Watkins, Jon Wilson, Matthew Wilson, Joshua Winchell, Dennis Wright, Steve Yellin, Betty Young, Xiaohe Zhang, Xuji Zhao
The Super Cryogenic Dark Matter Search experiment (SuperCDMS) at the Soudan Underground Laboratory studied energy loss associated with Frenkel defect formation in germanium crystals at mK temperatures using in situ $^{210}$Pb sources. We examine the spectrum of $^{206}$Pb nuclear recoils near its expected 103 keV endpoint energy and determine an energy loss of $\left(6.08\pm0.18\right)$ %, which we attribute to defect formation. From this result and using TRIM simulations, we extract the first experimentally determined average displacement threshold energy of $\left(19.7^{+0.6}_{-0.5}\right)$ eV for germanium. This has implications for the analysis thresholds of future germanium-based dark matter searches.
SuperCDMS Collaboration, Musaab Al-Bakry, Imran Alkhatib, Dorian Praia do Amaral, Taylor Aralis, Tsuguo Aramaki, Isaac Arnquist, Iman Ataee Langroudy, Elham Azadbakht, Samir Banik, Corey Bathurst, Dan Bauer, Lucas Bezerra, Rik Bhattacharyya, Paul Brink, Ray Bunker, Blas Cabrera, Robert Calkins, Robert Cameron, Concetta Cartaro, David Cerdeno, Yen-Yung Chang, Mouli Chaudhuri, Ran Chen, Nicholas Chott, Jodi Cooley, Harrison Coombes, Jonathan Corbett, Priscilla Cushman, François De Brienne, Sukeerthi Dharani, Maria Laura di Vacri, Miriam Diamond, Eleanor Fascione, Enectali Figueroa, Caleb Fink, Ken Fouts, Matt Fritts, Gilles Gerbier, Richard Germond, Muad Ghaith, Sunil Golwala, Jeter Hall, Noah Hassan, Bruce Hines, Matt Hollister, Ziqing Hong, Eric Hoppe, Lauren Hsu, Martin Huber, Vijay Iyer, Daniel Jardin, Andrew Jastram, Varchaswi Kashyap, Michael Kelsey, Andrew Kubik, Noah Kurinsky, Richard Lawrence, Matthew Lee, Ashley Li, Jasmine Liu, Yan Liu, Ben Loer, Pat Lukens, David MacFarlane, Rupak Mahapatra, Vuk Mandic, Nicholas Mast, Adam Mayer, Hanno Meyer zu Theenhausen, Émile Michaud, Emanuele Michielin, Nader Mirabolfathi, Bedangadas Mohanty, Serge Nagorny, Jack Nelson, Himangshu Neog, Valentina Novati, John Orrell, McKay Osborne, Scott Oser, William Page, Richard Partridge, David S. Pedreros, Ruslan Podviianiuk, Francisco Ponce, Sudip Poudel, Aditi Pradeep, Matt Pyle, Wolfgang Rau, Elliott Reid, Tom Ren, Tyler Reynolds, Amy Roberts, Alan Robinson, Tarek Saab, Bernard Sadoulet, Ishwita Saikia, Joel Sander, Ata Sattari, Benjamin Schmidt, Richard Schnee, Silvia Scorza, Bruno Serfass, Sagar Sharma Poudel, Derek Sincavage, Chris Stanford, Joseph Street, Huanbo Sun, Fatema Thasrawala, David Toback, Ryan Underwood, Shubham Verma, Anthony Villano, Belina von Krosigk, Samuel Watkins, Osmond Wen, Zachary Williams, Matthew Wilson, Joshua Winchell, Chih-pan Wu, Kevin Wykoff, Steve Yellin, Betty Young, To Chin Yu, Birgit Zatschler, Stefan Zatschler, Alexander Zaytsev, Enze Zhang, Lei Zheng, Summer Zuber
Daniel Baxter, Raymond Bunker, Sally Shaw, Shawn Westerdale, Isaac Arnquist, Daniel S. Akerib, Rob Calkins, Susana Cebrián, James B. Dent, Maria Laura di Vacri, Jim Dobson, Daniel Egana-Ugrinovic, Andrew Erlandson, Chamkaur Ghag, Carter Hall, Jeter Hall, Scott Haselschwardt, Eric Hoppe, Chris M. Jackson, Yonatan Kahn, Alvine Kamaha, Mike Kelsey, Alexander Kish, Noah Kurinsky, Matthias Laubenstein, Eric H. Miller, Eric Morrison, Brianna Mount, Jayden L. Newstead, Stefano Nisi, Ibles Olcina, John Orrell, Sergey Pereverzev, Emily Perry, Andreas Piepke, Sagar Sharma Poudel, Karthik Ramanathan, Juergen Reichenbacher, Tarek Saab, Richard Saldanha, Claudio Savarese, Richard Schnee, Silvia Scorza, Rajeev Singh, Kelly Stifter, Burkhant Suerfu, Matthew Szydagis, Dylan J. Temples, Anthony Villano, David Woodward, Jingke Xu
Future dark matter direct detection experiments will reach unprecedented levels of sensitivity. Achieving this sensitivity will require more precise models of signal and background rates in future detectors. Improving the precision of signal and background modeling goes hand-in-hand with novel calibration techniques that can probe rare processes and lower threshold detector response. The goal of this white paper is to outline community needs to meet the background and calibration requirements of next-generation dark matter direct detection experiments.
Marco Battaglieri, Alberto Belloni, Aaron Chou, Priscilla Cushman, Bertrand Echenard, Rouven Essig, Juan Estrada, Jonathan L. Feng, Brenna Flaugher, Patrick J. Fox, Peter Graham, Carter Hall, Roni Harnik, JoAnne Hewett, Joseph Incandela, Eder Izaguirre, Daniel McKinsey, Matthew Pyle, Natalie Roe, Gray Rybka, Pierre Sikivie, Tim M. P. Tait, Natalia Toro, Richard Van De Water, Neal Weiner, Kathryn Zurek, Eric Adelberger, Andrei Afanasev, Derbin Alexander, James Alexander, Vasile Cristian Antochi, David Mark Asner, Howard Baer, Dipanwita Banerjee, Elisabetta Baracchini, Phillip Barbeau, Joshua Barrow, Noemie Bastidon, James Battat, Stephen Benson, Asher Berlin, Mark Bird, Nikita Blinov, Kimberly K. Boddy, Mariangela Bondi, Walter M. Bonivento, Mark Boulay, James Boyce, Maxime Brodeur, Leah Broussard, Ranny Budnik, Philip Bunting, Marc Caffee, Sabato Stefano Caiazza, Sheldon Campbell, Tongtong Cao, Gianpaolo Carosi, Massimo Carpinelli, Gianluca Cavoto, Andrea Celentano, Jae Hyeok Chang, Swapan Chattopadhyay, Alvaro Chavarria, Chien-Yi Chen, Kenneth Clark, John Clarke, Owen Colegrove, Jonathon Coleman, David Cooke, Robert Cooper, Michael Crisler, Paolo Crivelli, Francesco D'Eramo, Domenico D'Urso, Eric Dahl, William Dawson, Marzio De Napoli, Raffaella De Vita, Patrick DeNiverville, Stephen Derenzo, Antonia Di Crescenzo, Emanuele Di Marco, Keith R. Dienes, Milind Diwan, Dongwi Handiipondola Dongwi, Alex Drlica-Wagner, Sebastian Ellis, Anthony Chigbo Ezeribe, Glennys Farrar, Francesc Ferrer, Enectali Figueroa-Feliciano, Alessandra Filippi, Giuliana Fiorillo, Bartosz Fornal, Arne Freyberger, Claudia Frugiuele, Cristian Galbiati, Iftah Galon, Susan Gardner, Andrew Geraci, Gilles Gerbier, Mathew Graham, Edda Gschwendtner, Christopher Hearty, Jaret Heise, Reyco Henning, Richard J. Hill, David Hitlin, Yonit Hochberg, Jason Hogan, Maurik Holtrop, Ziqing Hong, Todd Hossbach, T. B. Humensky, Philip Ilten, Kent Irwin, John Jaros, Robert Johnson, Matthew Jones, Yonatan Kahn, Narbe Kalantarians, Manoj Kaplinghat, Rakshya Khatiwada, Simon Knapen, Michael Kohl, Chris Kouvaris, Jonathan Kozaczuk, Gordan Krnjaic, Valery Kubarovsky, Eric Kuflik, Alexander Kusenko, Rafael Lang, Kyle Leach, Tongyan Lin, Mariangela Lisanti, Jing Liu, Kun Liu, Ming Liu, Dinesh Loomba, Joseph Lykken, Katherine Mack, Jeremiah Mans, Humphrey Maris, Thomas Markiewicz, Luca Marsicano, C. J. Martoff, Giovanni Mazzitelli, Christopher McCabe, Samuel D. McDermott, Art McDonald, Bryan McKinnon, Dongming Mei, Tom Melia, Gerald A. Miller, Kentaro Miuchi, Sahara Mohammed Prem Nazeer, Omar Moreno, Vasiliy Morozov, Frederic Mouton, Holger Mueller, Alexander Murphy, Russell Neilson, Tim Nelson, Christopher Neu, Yuri Nosochkov, Ciaran O'Hare, Noah Oblath, John Orrell, Jonathan Ouellet, Saori Pastore, Sebouh Paul, Maxim Perelstein, Annika Peter, Nguyen Phan, Nan Phinney, Michael Pivovaroff, Andrea Pocar, Maxim Pospelov, Josef Pradler, Paolo Privitera, Stefano Profumo, Mauro Raggi, Surjeet Rajendran, Nunzio Randazzo, Tor Raubenheimer, Christian Regenfus, Andrew Renshaw, Adam Ritz, Thomas Rizzo, Leslie Rosenberg, Andre Rubbia, Ben Rybolt, Tarek Saab, Benjamin R. Safdi, Elena Santopinto, Andrew Scarff, Michael Schneider, Philip Schuster, George Seidel, Hiroyuki Sekiya, Ilsoo Seong, Gabriele Simi, Valeria Sipala, Tracy Slatyer, Oren Slone, Peter F Smith, Jordan Smolinsky, Daniel Snowden-Ifft, Matthew Solt, Andrew Sonnenschein, Peter Sorensen, Neil Spooner, Brijesh Srivastava, Ion Stancu, Louis Strigari, Jan Strube, Alexander O. Sushkov, Matthew Szydagis, Philip Tanedo, David Tanner, Rex Tayloe, William Terrano, Jesse Thaler, Brooks Thomas, Brianna Thorpe, Thomas Thorpe, Javier Tiffenberg, Nhan Tran, Marco Trovato, Christopher Tully, Tony Tyson, Tanmay Vachaspati, Sven Vahsen, Karl van Bibber, Justin Vandenbroucke, Anthony Villano, Tomer Volansky, Guojian Wang, Thomas Ward, William Wester, Andrew Whitbeck, David A. Williams, Matthew Wing, Lindley Winslow, Bogdan Wojtsekhowski, Hai-Bo Yu, Shin-Shan Yu, Tien-Tien Yu, Xilin Zhang, Yue Zhao, Yi-Ming Zhong
A. E. Sharbaugh, L. Jones, A. N. Villano
The $^3$He(n,p) process is excellent for neutron detection between thermal and $\sim$4\,MeV because of the high cross section and near-complete energy transfer from the neutron to the proton. This process is typically used in gaseous forms with ionization readout detectors. Here we study the response of a liquid $^3$He neutron detector with a scintillation readout. We anticipate an efficiency boost of around a factor of 64 compared to 10\,atm gaseous detectors, given similar detector volumes.
SuperCDMS Collaboration, R. Agnese, A. J. Anderson, T. Aramaki, M. Asai, W. Baker, D. Balakishiyeva, D. Barker, R. Basu Thakur, D. A. Bauer, J. Billard, A. Borgland, M. A. Bowles, P. L. Brink, R. Bunker, B. Cabrera, D. O. Caldwell, R. Calkins, D. G. Cerdeno, H. Chagani, Y. Chen, J. Cooley, B. Cornell, P. Cushman, M. Daal, P. C. F. Di Stefano, T. Doughty, L. Esteban, S. Fallows, E. Figueroa-Feliciano, M. Ghaith, G. L. Godfrey, S. R. Golwala, J. Hall, H. R. Harris, T. Hofer, D. Holmgren, L. Hsu, M. E. Huber, D. Jardin, A. Jastram, O. Kamaev, B. Kara, M. H. Kelsey, A. Kennedy, A. Leder, B. Loer, E. Lopez Asamar, P. Lukens, R. Mahapatra, V. Mandic, N. Mast, N. Mirabolfathi, R. A. Moffatt, J. D. Morales Mendoza, S. M. Oser, K. Page, W. A. Page, R. Partridge, M. Pepin, A. Phipps, K. Prasad, M. Pyle, H. Qiu, W. Rau, P. Redl, A. Reisetter, Y. Ricci, A. Roberts, H. E. Rogers, T. Saab, B. Sadoulet, J. Sander, K. Schneck, R. W. Schnee, S. Scorza, B. Serfass, B. Shank, D. Speller, D. Toback, R. Underwood, S. Upadhyayula, A. N. Villano, B. Welliver, J. S. Wilson, D. H. Wright, S. Yellin, J. J. Yen, B. A. Young, J. Zhang
The CDMS low ionization threshold experiment (CDMSlite) uses cryogenic germanium detectors operated at a relatively high bias voltage to amplify the phonon signal in the search for weakly interacting massive particles (WIMPs). Results are presented from the second CDMSlite run with an exposure of 70 kg days, which reached an energy threshold for electron recoils as low as 56 eV. A fiducialization cut reduces backgrounds below those previously reported by CDMSlite. New parameter space for the WIMP-nucleon spin-independent cross section is excluded for WIMP masses between 1.6 and 5.5 GeV/$c^2$.
R. Agnese, A. J. Anderson, T. Aramaki, W. Baker, D. Balakishiyeva, S. Banik, D. Barker, R. Basu Thakur, D. A. Bauer, T. Binder, A. Borgland, M. A. Bowles, P. L. Brink, R. Bunker, B. Cabrera, D. O. Caldwell, R. Calkins, C. Cartaro, D. G. Cerdeno, H. Chagani, Y. -Y. Chang, Y. Chen, J. Cooley, B. Cornell, P. Cushman, M. Daal, T. Doughty, E. M. Dragowsky, L. Esteban, S. Fallows, E. Fascione, E. Figueroa-Feliciano, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, G. L. Godfrey, S. R. Golwala, J. Hall, H. R. Harris, D. Holmgren, Z. Hong, L. Hsu, M. E. Huber, V. Iyer, D. Jardin, A. Jastram, C. Jena, M. H. Kelsey, A. Kennedy, A. Kubik, N. A. Kurinsky, A. Leder, E. Lopez Asamar, P. Lukens, D. MacDonell, R. Mahapatra, V. Mandic, N. Mast, K. A. McCarthy, E. H. Miller, N. Mirabolfathi, R. A. Moffatt, B. Mohanty, D. Moore, J. D. Morales Mendoza, J. Nelson, S. M. Oser, K. Page, W. A. Page, R. Partridge, M. Penalver Martinez, M. Pepin, A. Phipps, S. Poudel, M. Pyle, H. Qiu, W. Rau, P. Redl, A. Reisetter, A. Roberts, H. E. Rogers, A. E. Robinson, T. Saab, B. Sadoulet, J. Sander, K. Schneck, R. W. Schnee, S. Scorza, K. Senapati, B. Serfass, D. Speller, P. C. F. Di Stefano, M. Stein, J. Street, H. A. Tanaka, D. Toback, R. Underwood, A. N. Villano, B. von Krosigk, B. Welliver, J. S. Wilson, M. J. Wilson, D. H. Wright, S. Yellin, J. J. Yen, B. A. Young, X. Zhang, X. Zhao
The Cryogenic Dark Matter Search (CDMS II) experiment aims to detect dark matter particles that elastically scatter from nuclei in semiconductor detectors. The resulting nuclear-recoil energy depositions are detected by ionization and phonon sensors. Neutrons produce a similar spectrum of low-energy nuclear recoils in such detectors, while most other backgrounds produce electron recoils. The absolute energy scale for nuclear recoils is necessary to interpret results correctly. The energy scale can be determined in CDMS II silicon detectors using neutrons incident from a broad-spectrum $^{252}$Cf source, taking advantage of a prominent resonance in the neutron elastic scattering cross section of silicon at a recoil (neutron) energy near 20 (182) keV. Results indicate that the phonon collection efficiency for nuclear recoils is $4.8^{+0.7}_{-0.9}$% lower than for electron recoils of the same energy. Comparisons of the ionization signals for nuclear recoils to those measured previously by other groups at higher electric fields indicate that the ionization collection efficiency for CDMS II silicon detectors operated at $\sim$4 V/cm is consistent with 100% for nuclear recoils below 20 keV and gradually decreases for larger energies to $\sim$75% at 100 keV. The impact of these measurements on previously published CDMS II silicon results is small.
R. Agnese, A. J. Anderson, T. Aramaki, I. Arnquist, W. Baker, D. Barker, R. Basu Thakur, D. A. Bauer, A. Borgland, M. A. Bowles, P. L. Brink, R. Bunker, B. Cabrera, D. O. Caldwell, R. Calkins, C. Cartaro, D. G. Cerdeño, H. Chagani, Y. Chen, J. Cooley, B. Cornell, P. Cushman, M. Daal, P. C. F. Di Stefano, T. Doughty, L. Esteban, S. Fallows, E. Figueroa-Feliciano, M. Fritts, G. Gerbier, M. Ghaith, G. L. Godfrey, S. R. Golwala, J. Hall, H. R. Harris, T. Hofer, D. Holmgren, Z. Hong, E. Hoppe, L. Hsu, M. E. Huber, V. Iyer, D. Jardin, A. Jastram, M. H. Kelsey, A. Kennedy, A. Kubik, N. A. Kurinsky, A. Leder, B. Loer, E. Lopez Asamar, P. Lukens, R. Mahapatra, V. Mandic, N. Mast, N. Mirabolfathi, R. A. Moffatt, J. D. Morales Mendoza, J. L. Orrell, S. M. Oser, K. Page, W. A. Page, R. Partridge, M. Pepin, A. Phipps, S. Poudel, M. Pyle, H. Qiu, W. Rau, P. Redl, A. Reisetter, A. Roberts, A. E. Robinson, H. E. Rogers, T. Saab, B. Sadoulet, J. Sander, K. Schneck, R. W. Schnee, B. Serfass, D. Speller, M. Stein, J. Street, H. A. Tanaka, D. Toback, R. Underwood, A. N. Villano, B. von Krosigk, B. Welliver, J. S. Wilson, D. H. Wright, S. Yellin, J. J. Yen, B. A. Young, X. Zhang, X. Zhao
SuperCDMS SNOLAB will be a next-generation experiment aimed at directly detecting low-mass (< 10 GeV/c$^2$) particles that may constitute dark matter by using cryogenic detectors of two types (HV and iZIP) and two target materials (germanium and silicon). The experiment is being designed with an initial sensitivity to nuclear recoil cross sections ~ 1 x 10$^{-43}$ cm$^2$ for a dark matter particle mass of 1 GeV/c$^2$, and with capacity to continue exploration to both smaller masses and better sensitivities. The phonon sensitivity of the HV detectors will be sufficient to detect nuclear recoils from sub-GeV dark matter. A detailed calibration of the detector response to low energy recoils will be needed to optimize running conditions of the HV detectors and to interpret their data for dark matter searches. Low-activity shielding, and the depth of SNOLAB, will reduce most backgrounds, but cosmogenically produced $^{3}$H and naturally occurring $^{32}$Si will be present in the detectors at some level. Even if these backgrounds are x10 higher than expected, the science reach of the HV detectors would be over three orders of magnitude beyond current results for a dark matter mass of 1 GeV/c$^2$. The iZIP detectors are relatively insensitive to variations in detector response and backgrounds, and will provide better sensitivity for dark matter particle masses (> 5 GeV/c$^2$). The mix of detector types (HV and iZIP), and targets (germanium and silicon), planned for the experiment, as well as flexibility in how the detectors are operated, will allow us to maximize the low-mass reach, and understand the backgrounds that the experiment will encounter. Upgrades to the experiment, perhaps with a variety of ultra-low-background cryogenic detectors, will extend dark matter sensitivity down to the "neutrino floor", where coherent scatters of solar neutrinos become a limiting background.
R. Agnese, A. J. Anderson, M. Asai, D. Balakishiyeva, R. Basu Thakur, D. A. Bauer, J. Beaty, J. Billard, A. Borgland, M. A. Bowles, D. Brandt, P. L. Brink, R. Bunker, B. Cabrera, D. O. Caldwell, D. G. Cerdeno, H. Chagani, Y. Chen, M. Cherry, J. Cooley, B. Cornell, C. H. Crewdson, P. Cushman, M. Daal, D. DeVaney, P. C. F. Di Stefano, E. Do Couto E Silva, T. Doughty, L. Esteban, S. Fallows, E. Figueroa-Feliciano, G. L. Godfrey, S. R. Golwala, J. Hall, S. Hansen, H. R. Harris, S. A. Hertel, B. A. Hines, T. Hofer, D. Holmgren, L. Hsu, M. E. Huber, A. Jastram, O. Kamaev, B. Kara, M. H. Kelsey, S. Kenany, A. Kennedy, M. Kiveni, K. Koch, A. Leder, B. Loer, E. Lopez Asamar, R. Mahapatra, V. Mandic, C. Martinez, K. A. McCarthy, N. Mirabolfathi, R. A. Moffatt, R. H. Nelson, L. Novak, K. Page, R. Partridge, M. Pepin, A. Phipps, M. Platt, K. Prasad, M. Pyle, H. Qiu, W. Rau, P. Redl, A. Reisetter, R. W. Resch, Y. Ricci, M. Ruschman, T. Saab, B. Sadoulet, J. Sander, R. L. Schmitt, K. Schneck, R. W. Schnee, S. Scorza, D. N. Seitz, B. Serfass, B. Shank, D. Speller, A. Tomada, S. Upadhyayula, A. N. Villano, B. Welliver, D. H. Wright, S. Yellin, J. J. Yen, B. A. Young, J. Zhang
We report a first search for weakly interacting massive particles (WIMPs) using the background rejection capabilities of SuperCDMS. An exposure of 577 kg-days was analyzed for WIMPs with mass < 30 GeV/c2, with the signal region blinded. Eleven events were observed after unblinding. We set an upper limit on the spin-independent WIMP-nucleon cross section of 1.2e-42 cm2 at 8 GeV/c2. This result is in tension with WIMP interpretations of recent experiments and probes new parameter space for WIMP-nucleon scattering for WIMP masses < 6 GeV/c2.
SuperCDMS Collaboration, M. F. Albakry, I. Alkhatib, D. W. P. Amaral, T. Aralis, T. Aramaki, I. J. Arnquist, I. Ataee Langroudy, E. Azadbakht, S. Banik, C. Bathurst, D. A. Bauer, R. Bhattacharyya, P. L. Brink, R. Bunker, B. Cabrera, R. Calkins, R. A. Cameron, C. Cartaro, D. G. Cerdeño, Y. -Y. Chang, M. Chaudhuri, R. Chen, N. Chott, J. Cooley, H. Coombes, J. Corbett, P. Cushman, F. De Brienne, S. Dharani, M. L. di Vacri, M. D. Diamond, E. Fascione, E. Figueroa-Feliciano, C. W. Fink, K. Fouts, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, S. R. Golwala, J. Hall, N. Hassan, B. A. Hines, M. I. Hollister, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyer, A. Jastram, V. K. S. Kashyap, M. H. Kelsey, A. Kubik, N. A. Kurinsky, R. E. Lawrence, M. Lee, A. Li, J. Liu, Y. Liu, B. Loer, E. Lopez Asamar, P. Lukens, D. B. MacFarlane, R. Mahapatra, V. Mandic, N. Mast, A. J. Mayer, H. Meyer zu Theenhausen, É. Michaud, E. Michielin, N. Mirabolfathi, B. Mohanty, S. Nagorny, J. Nelson, H. Neog, V. Novati, J. L. Orrell, M. D. Osborne, S. M. Oser, W. A. Page, R. Partridge, D. S. Pedreros, R. Podviianiuk, F. Ponce, S. Poudel, A. Pradeep, M. Pyle, W. Rau, E. Reid, R. Ren, T. Reynolds, A. Roberts, A. E. Robinson, T. Saab, B. Sadoulet, I. Saikia, J. Sander, A. Sattari, B. Schmidt, R. W. Schnee, S. Scorza, B. Serfass, S. S. Poudel, D. J. Sincavage, C. Stanford, J. Street, H. Sun, F. K. Thasrawala, D. Toback, R. Underwood, S. Verma, A. N. Villano, B. von Krosigk, S. L. Watkins, O. Wen, Z. Williams, M. J. Wilson, J. Winchell, K. Wykoff, S. Yellin, B. A. Young, T. C. Yu, B. Zatschler, S. Zatschler, A. Zaytsev, E. Zhang, L. Zheng, S. Zuber
Recent experiments searching for sub-GeV/$c^2$ dark matter have observed event excesses close to their respective energy thresholds. Although specific to the individual technologies, the measured excess event rates have been consistently reported at or below event energies of a few-hundred eV, or with charges of a few electron-hole pairs. In the present work, we operated a 1-gram silicon SuperCDMS-HVeV detector at three voltages across the crystal (0 V, 60 V and 100 V). The 0 V data show an excess of events in the tens of eV region. Despite this event excess, we demonstrate the ability to set a competitive exclusion limit on the spin-independent dark matter--nucleon elastic scattering cross section for dark matter masses of $\mathcal{O}(100)$ MeV/$c^2$, enabled by operation of the detector at 0 V potential and achievement of a very low $\mathcal{O}(10)$ eV threshold for nuclear recoils. Comparing the data acquired at 0 V, 60 V and 100 V potentials across the crystal, we investigated possible sources of the unexpected events observed at low energy. The data indicate that the dominant contribution to the excess is consistent with a hypothesized luminescence from the printed circuit boards used in the detector holder.
SuperCDMS Collaboration, I. Alkhatib, D. W. P. Amaral, T. Aralis, T. Aramaki, I. J. Arnquist, I. Ataee Langroudy, E. Azadbakht, S. Banik, D. Barker, C. Bathurst, D. A. Bauer, L. V. S. Bezerra, R. Bhattacharyya, M. A. Bowles, P. L. Brink, R. Bunker, B. Cabrera, R. Calkins, R. A. Cameron, C. Cartaro, D. G. Cerdeño, Y. -Y. Chang, M. Chaudhuri, R. Chen, N. Chott, J. Cooley, H. Coombes, J. Corbett, P. Cushman, F. De Brienne, M. L. di Vacri, M. D. Diamond, E. Fascione, E. Figueroa-Feliciano, C. W. Fink, K. Fouts, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, S. R. Golwala, H. R. Harris, B. A. Hines, M. I. Hollister, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyer, D. Jardin, A. Jastram, V. K. S. Kashyap, M. H. Kelsey, A. Kubik, N. A. Kurinsky, R. E. Lawrence, A. Li, B. Loer, E. Lopez Asamar, P. Lukens, D. B. MacFarlane, R. Mahapatra, V. Mandic, N. Mast, A. J. Mayer, H. Meyer zu Theenhausen, É. M. Michaud, E. Michielin, N. Mirabolfathi, B. Mohanty, J. D. Morales Mendoza, S. Nagorny, J. Nelson, H. Neog, V. Novati, J. L. Orrell, S. M. Oser, W. A. Page, R. Partridge, R. Podviianiuk, F. Ponce, S. Poudel, A. Pradeep, M. Pyle, W. Rau, E. Reid, R. Ren, T. Reynolds, A. Roberts, A. E. Robinson, T. Saab, B. Sadoulet, J. Sander, A. Sattari, R. W. Schnee, S. Scorza, B. Serfass, D. J. Sincavage, C. Stanford, J. Street, D. Toback, R. Underwood, S. Verma, A. N. Villano, B. von Krosigk, S. L. Watkins, J. S. Wilson, M. J. Wilson, J. Winchell, D. H. Wright, S. Yellin, B. A. Young, T. C. Yu, E. Zhang, H. G. Zhang, X. Zhao, L. Zheng
The Cryogenic Dark Matter Search low ionization threshold experiment (CDMSlite) achieved efficient detection of very small recoil energies in its germanium target, resulting in sensitivity to Lightly Ionizing Particles (LIPs) in a previously unexplored region of charge, mass, and velocity parameter space. We report first direct-detection limits calculated using the optimum interval method on the vertical intensity of cosmogenically-produced LIPs with an electric charge smaller than $e/(3\times10^5$), as well as the strongest limits for charge $\leq e/160$, with a minimum vertical intensity of $1.36\times10^{-7}$\,cm$^{-2}$s$^{-1}$sr$^{-1}$ at charge $e/160$. These results apply over a wide range of LIP masses (5\,MeV/$c^2$ to 100\,TeV/$c^2$) and cover a wide range of $βγ$ values (0.1 -- $10^6$), thus excluding non-relativistic LIPs with $βγ$ as small as 0.1 for the first time.
A. N. Villano, Kitty C. Harris, Judit Bergfalk, Raphael Hatami, Francis Vititoe, Julia Johnston
Dark matter is estimated to make up ~84% of all normal/baryonic matter, but cannot be directly imaged. Despite the fact that dark matter cannot be directly observed yet, its influence on the motion of stars and gas in spiral galaxies have been detected. One way to show motion in galaxies are rotation curves that are plots of velocity measurements of how fast stars and gas move in a galaxy around the center of mass. According to Newton's Law of Gravitation, the rotational velocity is an indication of the amount of visible and non-visible mass in the galaxy. Given that the visible matter is measurable using photometry, dark matter mass can therefore be estimated, offering an insight into the size distribution in galaxies. In order to gain a greater appreciation of the research scientists' findings about dark matter, their method should be easily reproduced by any curious individual. Our interactive workshop is an excellent educational tool to investigate how dark matter impacts the rotation of visible matter by providing a guide to produce galactic rotation curves. The Python-based notebooks are set up to walk you through the whole process of producing rotation curves using an online database (SPARC) and to allow you to learn about each component of the galaxy. The three steps of the rotation curve building process is plotting the measured velocity data, constructing the rotation curves for each component, and fitting the total velocity to the measured values.
A. N. Villano
The $^3$He(n,p) process is excellent for neutron detection between thermal and $\sim$4\,MeV because of the high cross section and near-complete energy transfer from the neutron to the proton. Traditional gaseous $^3$He detectors using this process typically have high levels of radiogenic backgrounds so that they cannot measure the small neutron fluxes present in underground labs for dark matter experiments. I propose a cryogenic liquid $^3$He detector that can be designed with tiny radiogenic backgrounds and efficiently measure neutron fluxes in low-flux environments.
SuperCDMS Collaboration, M. F. Albakry, I. Alkhatib, D. Alonso-Gonźalez, D. W. P. Amaral, J. Anczarski, T. Aralis, T. Aramaki, I. Ataee Langroudy, C. Bathurst, R. Bhattacharyya, A. J. Biffl, P. L. Brink, M. Buchanan, R. Bunker, B. Cabrera, R. Calkins, R. A. Cameron, C. Cartaro, D. G. Cerdeño, Y. -Y. Chang, M. Chaudhuri, J. -H. Chen, R. Chen, N. Chott, J. Cooley, H. Coombes, P. Cushman, R. Cyna, S. Das, S. Dharani, M. L. di Vacri, M. D. Diamond, M. Elwan, S. Fallows, E. Fascione, E. Figueroa-Feliciano, S. L. Franzen, A. Gevorgian, M. Ghaith, G. Godden, J. Golatkar, S. R. Golwala, R. Gualtieri, J. Hall, S. A. S. Harms, C. Hays, B. A. Hines, Z. Hong, L. Hsu, M. E. Huber, V. Iyer, V. K. S. Kashyap, S. T. D. Keller, M. H. Kelsey, K. T. Kennard, Z. Kromer, A. Kubik, N. A. Kurinsky, M. Lee, J. Leyva, B. Lichtenberg, J. Liu, Y. Liu, E. Lopez Asamar, P. Lukens, R. López Noé, D. B. MacFarlane, R. Mahapatra, J. S. Mammo, N. Mast, A. J. Mayer, P. C. McNamara, H. Meyer zu Theenhausen, É. Michaud, E. Michielin, K. Mickelson, N. Mirabolfathi, M. Mirzakhani, B. Mohanty, D. Mondal, D. Monteiro, J. Nelson, H. Neog, V. Novati, J. L. Orrell, M. D. Osborne, S. M. Oser, L. Pandey, S. Pandey, R. Partridge, P. K. Patel, D. S. Pedreros, W. Peng, W. L. Perry, R. Podviianiuk, M. Potts, S. S. Poudel, A. Pradeep, M. Pyle, W. Rau, E. Reid, R. Ren, T. Reynolds, M. Rios, A. Roberts, A. E. Robinson, L. Rosado Del Rio, J. L. Ryan, T. Saab, D. Sadek, B. Sadoulet, S. P. Sahoo, I. Saikia, S. Salehi, J. Sander, B. Sandoval, A. Sattari, B. Schmidt, R. W. Schnee, B. Serfass, A. E. Sharbaugh, R. S. Shenoy, A. Simchony, P. Sinervo, Z. J. Smith, R. Soni, K. Stifter, J. Street, M. Stukel, H. Sun, E. Tanner, N. Tenpas, D. Toback, A. N. Villano, J. Viol, B. von Krosigk, Y. Wang, O. Wen, Z. Williams, M. J. Wilson, J. Winchell, S. Yellin, B. A. Young, B. Zatschler, S. Zatschler, A. Zaytsev, E. Zhang, L. Zheng, A. Zuniga, M. J. Zurowski
Cryogenic calorimeters for low-mass dark matter searches have achieved sub-eV energy resolutions, driving advances in both low-energy calibration techniques and our understanding of detector physics. The energy deposition spectrum of gamma rays scattering off target materials exhibits step-like features, known as Compton steps, near the binding energies of atomic electrons. We demonstrate a successful use of Compton steps for sub-keV calibration of cryogenic silicon calorimeters, utilizing four SuperCDMS High-Voltage eV-resolution (HVeV) detectors operated with 0 V bias across the crystal. This new calibration at 0 V is compared with the established high-voltage calibration using optical photons. The comparison indicates that the detector response at 0 V is about 30% weaker than expected, highlighting challenges in detector response modeling for low-mass dark matter searches.
SuperCDMS Collaboration, R. Agnese, A. J. Anderson, D. Balakishiyeva, R. Basu Thakur, D. A. Bauer, J. Billard, A. Borgland, M. A. Bowles, D. Brandt, P. L. Brink, R. Bunker, B. Cabrera, D. O. Caldwell, D. G. Cerdeno, H. Chagani, Y. Chen, J. Cooley, B. Cornell, C. H. Crewdson, P. Cushman, M. Daal, P. C. F. Di Stefano, T. Doughty, L. Esteban, S. Fallows, E. Figueroa-Feliciano, M. Fritts, G. L. Godfrey, S. R. Golwala, M. Graham, J. Hall, H. R. Harris, S. A. Hertel, T. Hofer, D. Holmgren, L. Hsu, M. E. Huber, A. Jastram, O. Kamaev, B. Kara, M. H. Kelsey, A. Kennedy, M. Kiveni, K. Koch, A. Leder, B. Loer, E. Lopez Asamar, R. Mahapatra, V. Mandic, C. Martinez, K. A. McCarthy, N. Mirabolfathi, R. A. Moffatt, D. C. Moore, R. H. Nelson, S. M. Oser, K. Page, W. A. Page, R. Partridge, M. Pepin, A. Phipps, K. Prasad, M. Pyle, H. Qiu, W. Rau, P. Redl, A. Reisetter, Y. Ricci, H. E. Rogers, T. Saab, B. Sadoulet, J. Sander, K. Schneck, R. W. Schnee, S. Scorza, B. Serfass, B. Shank, D. Speller, S. Upadhyayula, A. N. Villano, B. Welliver, D. H. Wright, S. Yellin, J. J. Yen, B. A. Young, J. Zhang
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 $^{210}$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.
A. N. Villano, M. Fritts, N. Mast, S. Brown, P. Cushman, K. Harris, V. Mandic
Low-energy nuclear recoils (NRs) are hard to measure because they produce few e$^{-}$/h$^+$ pairs in solids -- i.e. they have low "ionization yield". A silicon detector was exposed to thermal neutrons over 2.5\,live-days, probing NRs down to 450\,eV. The observation of a neutron capture-induced component of NRs at low energies is supported by the much-improved fit upon inclusion of a capture NR model. This result shows that thermal neutron calibration of very low recoil energy NRs is promising for dark matter searches, coherent neutrino experiments, and improving understanding of ionization dynamics in solids.
A J Biffl, Gerardo D Gonzalez, A N Villano, N Mirabolfathi
The lattice dynamics following particle interactions remain not fully understood, and effects from nuclear-recoil interactions in conventional solid-state detectors - such as defect formation - can hinder accurate event-energy interpretation. Neutron capture $(n,γ)$ can produce detectable, precise-energy nuclear recoils for detector calibration and solid-state physics studies. This paper proposes a first-of-its-kind experiment to measure the twin products of neutron capture - the postcapture deexcitation gamma and postcapture nuclear recoil. Simulations show that with a 1 mCi californium neutron source, a positive measurement with existing detector technologies is possible in 26.1 gram-days of exposure.
M. F. Albakry, I. Alkhatib, D. Alonso, D. W. P. Amaral, P. An, T. Aralis, T. Aramaki, I. J. Arnquist, I. Ataee Langroudy, E. Azadbakht, S. Banik, P. S. Barbeau, C. Bathurst, R. Bhattacharyya, P. L. Brink, R. Bunker, B. Cabrera, R. Calkins, R. A. Cameron, C. Cartaro, D. G. Cerdeño, Y. -Y. Chang, M. Chaudhuri, R. Chen, N. Chott, J. Cooley, H. Coombes, J. Corbett, P. Cushman, S. Das, F. De Brienne, M. Rios, S. Dharani, M. L. di Vacri, M. D. Diamond, M. Elwan, E. Fascione, E. Figueroa-Feliciano, C. W. Fink, K. Fouts, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, S. R. Golwala, J. Hall, N. Hassan, S. C. Hedges, B. A. Hines, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyer, V. K. S. Kashyap, M. H. Kelsey, A. Kubik, N. A. Kurinsky, M. Lee, A. Li, L. Li, M. Litke, J. Liu, Y. Liu, B. Loer, E. Lopez Asamar, P. Lukens, D. B. MacFarlane, R. Mahapatra, V. Mandic, N. Mast, A. J. Mayer, H. Meyer zu Theenhausen, . Michaud, E. Michielin, N. Mirabolfathi, B. Mohanty, B. Nebolsky, J. Nelson, H. Neog, V. Novati, J. L. Orrell, M. D. Osborne, S. M. Oser, W. A. Page, S. Pandey, R. Partridge, D. S. Pedreros, L. Perna, R. Podviianiuk, F. Ponce, S. Poudel, A. Pradeep, M. Pyle, W. Rau, E. Reid, R. Ren, T. Reynolds, A. Roberts, A. E. Robinson, J. Runge, T. Saab, D. Sadek, B. Sadoulet, I. Saikia, J. Sander, A. Sattari, B. Schmidt, R. W. Schnee, S. Scorza, B. Serfass, S. S. Poudel, D. J. Sincavage, P. Sinervo, Z. Speaks, J. Street, H. Sun, F. K. Thasrawala, D. Toback, R. Underwood, S. Verma, A. N. Villano, B. von Krosigk, S. L. Watkins, O. Wen, Z. Williams, M. J. Wilson, J. Winchell, K. Wykoff, S. Yellin, B. A. Young, T. C. Yu, B. Zatschler, S. Zatschler, A. Zaytsev, A. Zeolla, E. Zhang, L. Zheng, Y. Zheng, A. Zuniga
We measured the nuclear--recoil ionization yield in silicon with a cryogenic phonon-sensitive gram-scale detector. Neutrons from a mono-energetic beam scatter off of the silicon nuclei at angles corresponding to energy depositions from 4\,keV down to 100\,eV, the lowest energy probed so far. The results show no sign of an ionization production threshold above 100\,eV. These results call for further investigation of the ionization yield theory and a comprehensive determination of the detector response function at energies below the keV scale.
M. F. Albakry, I. Alkhatib, D. Alonso, D. W. P. Amaral, T. Aralis, T. Aramaki, I. J. Arnquist, I. Ataee Langroudy, E. Azadbakht, S. Banik, C. Bathurst, R. Bhattacharyya, P. L. Brink, R. Bunker, B. Cabrera, R. Calkins, R. A. Cameron, C. Cartaro, D. G. Cerdeño, Y. -Y. Chang, M. Chaudhuri, R. Chen, N. Chott, J. Cooley, H. Coombes, J. Corbett, P. Cushman, S. Das, F. De Brienne, M. Rios, S. Dharani, M. L. di Vacri, M. D. Diamond, M. Elwan, E. Fascione, E. Figueroa-Feliciano, C. W. Fink, K. Fouts, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, S. R. Golwala, J. Hall, N. Hassan, B. A. Hines, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyer, D. Jardin, V. K. S. Kashyap, M. H. Kelsey, A. Kubik, N. A. Kurinsky, M. Lee, A. Li, M. Litke, J. Liu, Y. Liu, B. Loer, E. Lopez Asamar, P. Lukens, D. B. MacFarlane, R. Mahapatra, N. Mast, A. J. Mayer, H. Meyer zu Theenhausen, É. Michaud, E. Michielin, N. Mirabolfathi, B. Mohanty, J. Nelson, H. Neog, V. Novati, J. L. Orrell, M. D. Osborne, S. M. Oser, W. A. Page, S. Pandey, R. Partridge, D. S. Pedreros, L. Perna, R. Podviianiuk, F. Ponce, S. Poudel, A. Pradeep, M. Pyle, W. Rau, E. Reid, R. Ren, T. Reynolds, A. Roberts, A. E. Robinson, T. Saab, D. Sadek, B. Sadoulet, I. Saikia, J. Sander, A. Sattari, B. Schmidt, R. W. Schnee, S. Scorza, B. Serfass, S. S. Poudel, D. J. Sincavage, P. Sinervo, J. Street, H. Sun, G. D. Terry, F. K. Thasrawala, D. Toback, R. Underwood, S. Verma, A. N. Villano, B. von Krosigk, S. L. Watkins, O. Wen, Z. Williams, M. J. Wilson, J. Winchell, C. -P. Wu, K. Wykoff, S. Yellin, B. A. Young, T. C. Yu, B. Zatschler, S. Zatschler, A. Zaytsev, E. Zhang, L. Zheng, A. Zuniga
We present a new analysis of previously published of SuperCDMS data using a profile likelihood framework to search for sub-GeV dark matter (DM) particles through two inelastic scattering channels: bremsstrahlung radiation and the Migdal effect. By considering these possible inelastic scattering channels, experimental sensitivity can be extended to DM masses that are undetectable through the DM-nucleon elastic scattering channel, given the energy threshold of current experiments. We exclude DM masses down to $220~\textrm{MeV}/c^2$ at $2.7 \times 10^{-30}~\textrm{cm}^2$ via the bremsstrahlung channel. The Migdal channel search provides overall considerably more stringent limits and excludes DM masses down to $30~\textrm{MeV}/c^2$ at $5.0 \times 10^{-30}~\textrm{cm}^2$.