H. A. Tanaka

A Search for electron neutrino appearance at the

A. A. Aguilar-Arevalo, A. O. Bazarko, S. J. Brice, B. C. Brown, L. Bugel, J. Cao, L. Coney, J. M. Conrad, D. C. Cox, A. Curioni, Z. Djurcic, D. A. Finley, B. T. Fleming, R. Ford, F. G. Garcia, G. T. Garvey, C. Green, J. A. Green, T. L. Hart, E. Hawker, R. Imlay, R. A. Johnson, P. Kasper, T. Katori, T. Kobilarcik, I. Kourbanis, S. Koutsoliotas, E. M. Laird, J. M. Link, Y. Liu, Y. Liu, W. C. Louis, K. B. M. Mahn, W. Marsh, P. S. Martin, G. McGregor, W. Metcalf, P. D. Meyers, F. Mills, G. B. Mills, J. Monroe, C. D. Moore, R. H. Nelson, P. Nienaber, S. Ouedraogo, R. B. Patterson, D. Perevalov, C. C. Polly, E. Prebys, J. L. Raaf, H. Ray, B. P. Roe, A. D. Russell, V. Sandberg, R. Schirato, D. Schmitz, M. H. Shaevitz, F. C. Shoemaker, D. Smith, M. Sorel, P. Spentzouris, I. Stancu, R. J. Stefanski, M. Sung, H. A. Tanaka, R. Tayloe, M. Tzanov, R. Van de Water, M. O. Wascko, D. H. White, M. J. Wilking, H. J. Yang, G. P. Zeller, E. D. Zimmerman

\Delta m^{2} \sim 1

SuperCDMS SNOLAB will be a next-generation experiment aimed at directly detecting low-mass particles (with masses ≤ 10 GeV/c^2) 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 ∼ 1×10^(−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 ^3H and naturally occurring ^(32)Si will be present in the detectors at some level. Even if these backgrounds are 10 times higher than expected, the science reach of the HV detectors would be over 3 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 particles with 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.

eV

T2K is a long-baseline neutrino oscillation experiment searching for νe appearance in a νμ beam. The beam is produced at the J-PARC accelerator complex in Tokai, Japan, and the neutrinos are detected by the SuperKamiokande detector located 295 km away in Kamioka. A suite of near detectors (ND280) located 280 m downstream of the production target is used to characterize the components of the beam before they have had a chance to oscillate and to better understand various neutrino interactions on several nuclei. This paper describes the design and construction of two massive fine-grained detectors (FGDs) that serve as active targets in the ND280 tracker. One FGD is composed solely of scintillator bars while the other is partly scintillator and partly water. Each element of the FGDs is described, including the wavelength shifting fiber and Multi-Pixel Photon Counter used to collect the light signals, the readout electronics, and the calibration system. Initial tests and in situ results of the FGDs’ performance are also presented.

^{2}

In line with its terms of reference the ICFA Neutrino Panel has developed a roadmapfor the international, accelerator-based neutrino programme. A roadmap discussion document was presented in May 2016 taking into account the peer-group-consultation described in the Panels initial report. The roadmap discussion document was used to solicit feedback from the neutrino community---and more broadly, the particle- and astroparticle-physics communities---and the various stakeholders in the programme. The roadmap, the conclusions and recommendations presented in this document take into account the comments received following the publication of the roadmap discussion document. nWith its roadmap the Panel documents the approved objectives and milestones of the experiments that are presently in operation or under construction. Approval, construction and exploitation milestones are presented for experiments that are being considered for approval. The timetable proposed by the proponents is presented for experiments that are not yet being considered formally for approval. Based on this information, the evolution of the precision with which the critical parameters governinger the neutrino are known has been evaluated. Branch or decision points have been identified based on the anticipated evolution in precision. The branch or decision points have in turn been used to identify desirable timelines for the neutrino-nucleus cross section and hadro-production measurements that are required to maximise the integrated scientific output of the programme. The branch points have also been used to identify the timeline for the R&D required to take the programme beyond the horizon of the next generation of experiments. The theory and phenomenology programme, including nuclear theory, required to ensure that maximum benefit is derived from the experimental programme is also discussed.

scale

The combined cross section for absorption and charge exchange interactions of positively charged pions with carbon nuclei for the momentum range 200 MeV/c to 300 MeV/c have been measured with the DUET experiment at TRIUMF. The uncertainty is reduced by nearly half compared to previous experiments. This result will be a valuable input to existing models to constrain pion interactions with nuclei.

Projected sensitivity of the SuperCDMS SNOLAB experiment

A. A. Aguilar-Arevalo, A. O. Bazarko, S. J. Brice, B. C. Brown, L. Bugel, J. Cao, L. Coney, J. M. Conrad, D. C. Cox, A. Curioni, Z. Djurcic, D. A. Finley, B. T. Fleming, R. Ford, F. G. Garcia, G. T. Garvey, C. Green, J. A. Green, T. L. Hart, E. Hawker, R. Imlay, R. A. Johnson, P. Kasper, T. Katori, T. Kobilarcik, I. Kourbanis, S. Koutsoliotas, E. M. Laird, J. M. Link, Y. Liu, Y. Liu, W. C. Louis, K. B. M. Mahn, W. Marsh, P. S. Martin, G. McGregor, W. Metcalf, P. D. Meyers, F. Mills, G. B. Mills, J. Monroe, C. D. Moore, R. H. Nelson, P. Nienaber, S. Ouedraogo, R. B. Patterson, D. Perevalov, C. C. Polly, E. Prebys, J. L. Raaf, H. Ray, B. P. Roe, A. D. Russell, V. Sandberg, R. Schirato, D. Schmitz, M. H. Shaevitz, F. C. Shoemaker, D. Smith, M. Sorel, P. Spentzouris, I. Stancu, R. J. Stefanski, M. Sung, H. A. Tanaka, R. Tayloe, M. Tzanov, R. Van de Water, M. O. Wascko, D. H. White, M. J. Wilking, H. J. Yang, G. P. Zeller, E. D. Zimmerman

The T2K fine-grained detectors

The Super Cryogenic Dark Matter Search experiment at the Soudan Underground Laboratory studied energy loss associated with defect formation in germanium crystals at mK temperatures using in situ 210Pb sources. We examine the spectrum of 206Pb nuclear recoils near its expected 103u2009keV endpoint energy and determine an energy loss of (6:08u2009±u20090:18)%, which we attribute to defect formation. From this result and using TRIM simulations, we extract the first experimentally determined average displacement threshold energy of 19.7−0.5+0.6 eV for germanium. This has implications for the analysis thresholds of future germanium-based dark matter searches.The Super Cryogenic Dark Matter Search experiment at the Soudan Underground Laboratory studied energy loss associated with defect formation in germanium crystals at mK temperatures using in situ 210Pb sources. We examine the spectrum of 206Pb nuclear recoils near its expected 103u2009keV endpoint energy and determine an energy loss of (6:08u2009±u20090:18)%, which we attribute to defect formation. From this result and using TRIM simulations, we extract the first experimentally determined average displacement threshold energy of 19.7−0.5+0.6 eV for germanium. This has implications for the analysis thresholds of future germanium-based dark matter searches.

Roadmap for the international, accelerator-based neutrino programme

The DUET Collaboration reports on the measurements of the absorption (

Measurement of absorption and charge exchange of

sigma_{mathrm{ABS}}

\pi^+

) and charge exchange (