A. J. Anderson

We report results of a search for weakly interacting massive particles (WIMPS) with the silicon detectors of the CDMS II experiment. This blind analysis of 140.2 kg day of data taken between July 2007 and September 2008 revealed three WIMP-candidate events with a surface-event background estimate of ${0.41}_{\ensuremath{-}0.08}^{+0.20}(\mathrm{stat}{)}_{\ensuremath{-}0.24}^{+0.28}(\mathrm{syst})$. Other known backgrounds from neutrons and $^{206}\mathrm{Pb}$ are limited to $<0.13$ and $<0.08$ events at the 90% confidence level, respectively. The exposure of this analysis is equivalent to 23.4 kg day for a recoil energy range of 7--100 keV for a WIMP of mass $10\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. The probability that the known backgrounds would produce three or more events in the signal region is 5.4%. A profile likelihood ratio test of the three events that includes the measured recoil energies gives a 0.19% probability for the known-background-only hypothesis when tested against the alternative $\mathrm{\text{WIMP}}+\mathrm{\text{background}}$ hypothesis. The highest likelihood occurs for a WIMP mass of $8.6\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ and WIMP-nucleon cross section of $1.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}41}\text{ }\text{ }{\mathrm{cm}}^{2}$.

The (3+3) research programme posits that spacetime is six-dimensional with signature (+,+,+,-,-,-) — three spatial dimensions and three time-like dimensions — and that the third time-like dimension t_3 is compactified as a discrete two-sphere S^2 with 2^152 Planck-area cells. From this geometric starting point, together with the t_2 precession dynamics driven by the tribonacci constant, the programme derives 25+ observationally distinct phenomena without free parameters, spanning the Standard Model (fine structure constant at 7 ppb, proton-to-electron mass ratio at 0.008%, three fermion generations, strong CP, CP phases), quantum foundations (Born rule, Schrodinger equation, complex-valuedness, spin-statistics, Bell/Tsirelson bound), and cosmology (Hubble tension, six CMB anomalies, dark matter identity and abundance at 0.02%, preferred-axis large-scale structure). This paper is the programme’s entry point. It differs from the eleven companion preprints in its purpose rather than its content. The companion preprints each develop one specific application of the framework with full technical derivations; this paper does not re-derive any of them. Instead it presents the (3+3) geometry axiomatically — taking the six-dimensional spacetime with discrete-S^2 compactification as given, rather than arguing for its necessity — and shows what follows from the axioms, with structured pointers to the application papers for the full derivations. The paper is aimed at readers who want to assess the programme before committing to the 500-page book manuscript that justifies the axioms from first principles. The paper establishes six things: (A) a clean axiomatic presentation of the (3+3) geometry as six explicit axioms; (B) the immediate structural consequences of the geometry (trisection N_c = 3; 12 pentagonal defects; magic angle 54.74 degrees; CP tilt 14.48 degrees; half-integer spin from SU(2) double cover; hbar as derived quantity); (C) quantum mechanics as geometry (wavefunction as direction on S^2; psi in C from t_2 rotation; Schrodinger from linearised t_2 precession; Born rule via three convergent routes; Tsirelson = dim(S^2) = 2; cosmological decoherence floor 14.5 Gyr); (D) Standard Model parameters from geometry (alpha at 7 ppb; m_p/m_e at 0.008%; three generations; strong CP resolution; delta_PMNS = 194.48 degrees; spin-statistics); (E) cosmology from geometry (Hubble tension resolution; six CMB anomalies as projections of one structure; dark matter as n=0 KK condensate with alpha_23 = 0.8428 at 0.02%; intrinsic CMB dipole; preferred-axis LSS); (F) the unification claim — a consolidated table of 25+ derived phenomena from one geometric postulate. The paper is explicit about what it does not do. It does not derive the geometry from first principles (book [1]’s role). It does not reproduce any application-paper derivation (those live in [2–12]). It does not claim the framework is established as correct. Six open items are explicitly consolidated at the programme level (section 10): no 6D Lagrangian formulation; S^2 uniqueness only partially addressed; path-integral reformulation absent; interpretive comparisons with QBism, relational quantum mechanics, consistent histories undeveloped; precision amplitudes for CMB anomalies not derived; programme-level gaps including General Relativity reconstruction, QFT beyond Standard Model, black-hole thermodynamics, collider predictions, pedagogical development. Falsifiability is concentrated at named experiments through 2035 (section 11): DUNE and Hyper-Kamiokande on delta_PMNS = 194.48 degrees; neutron-EDM at PSI/ILL/SNS on strong CP; CMB-S4, LiteBIRD, Simons Observatory on the 11 additional cold spots and anomaly axis convergence; DESI 2028 on intrinsic CMB dipole and 3-fold LSS symmetry; precision Bell tests on Tsirelson saturation; real-QM falsification reconfirmation. Nine independent falsification routes covering the entire programme. The programme’s distinguishing feature is the combination of specific numerical predictions (alpha at 7 ppb, m_p/m_e at 0.008%, alpha_23 at 0.02%), named experimental tests at specific facilities with specific timeframes, zero free parameters, and scope across three physical domains (particle physics, quantum foundations, cosmology) from the same geometric substrate. This paper is the shortest path for a reader to assess whether the combination is compelling before committing to any deeper read.

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 day, 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}.

SuperCDMS SNOLAB will be a next-generation experiment aimed at directly detecting low-mass particles (with masses $\ensuremath{\le}10\text{ }\text{ }\mathrm{GeV}/{\mathrm{c}}^{2}$) 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 $\ensuremath{\sim}1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}43}\text{ }\text{ }{\mathrm{cm}}^{2}$ for a dark matter particle mass of $1\text{ }\text{ }\mathrm{GeV}/{\mathrm{c}}^{2}$, 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 $^{3}\mathrm{H}$ and naturally occurring $^{32}\mathrm{Si}$ 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 $1\text{ }\text{ }\mathrm{GeV}/{\mathrm{c}}^{2}$. The iZIP detectors are relatively insensitive to variations in detector response and backgrounds, and will provide better sensitivity for dark matter particles with masses $\ensuremath{\gtrsim}5\text{ }\text{ }\mathrm{GeV}/{\mathrm{c}}^{2}$. 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.

SuperCDMS is an experiment designed to directly detect weakly interacting massive particles (WIMPs), a favored candidate for dark matter ubiquitous in the Universe. In this Letter, we present WIMP-search results using a calorimetric technique we call CDMSlite, which relies on voltage-assisted Luke-Neganov amplification of the ionization energy deposited by particle interactions. The data were collected with a single 0.6 kg germanium detector running for ten live days at the Soudan Underground Laboratory. A low energy threshold of 170 eVee (electron equivalent) was obtained, which allows us to constrain new WIMP-nucleon spin-independent parameter space for WIMP masses below 6 GeV/c2.