Results are reported of an experimental search for the unique, rapidly varying temporal pattern of solar axions coherently converting into photons via the Primakoff effect in a single crystal germanium detector when axions are incident at a Bragg angle with a crystalline plane. The analysis of 1.94 kg yr of data from the 1 kg DEMOS detector in Sierra Grande, Argentina, yields a new laboratory bound by an axion-photon coupling of g agg , 2.7 3 10 29 GeV 21 , independent of axion mass up to ϳ1 keV. [S0031-9007(98)07812-0] PACS numbers: 14.80. Mz, 96.60.Vg Early QCD theories predicted a particle with the quantum numbers of the h meson, but with a mass close to that of the pion. A term added to the QCD Lagrangian to ameliorate this so-called U(1) problem violated CP invariance in strong interactions and implied a neutron electric-dipole moment about 10 9 times larger than the experimental upper bound [1]. Peccei and Quinn [2] introduced a new field causing strong CP violation to vanish dynamically. Subsequently, Weinberg [3,4] and Wilczek [5] demonstrated that the Peccei-Quinn mechanism generates a Nambu-Goldstone boson, the axion, that couples to a two-photon vertex via a coupling g agg . Axion production via the Primakoff effect occurs when a photon couples to a charge via a virtual photon, producing an axion. Detection can occur by observing photons resulting from axions coupling to electrical charges via virtual photons.The dense volume of photons and charges in the sun or any star produces conditions for axion production. The Ge detector then can act as the axion-photon converter and detector. When the characteristic wavelength of the axion satisfies a Bragg condition in the single crystal Ge detector, photon production would occur with an expected temporal pattern depending on the changing relative directions between the vectors from the solar core and the crystalline planes.Extensive reviews of axion phenomenology and their effects on stellar evolution have been given by Raffelt [6,7] who gives a bound of 10 210 GeV 21 on the coupling of axions to the two-photon vertex from the population of red giant stars. A detailed treatment of solar axions and of a proposed method of detecting them was given by van Bibber et al. [8]. Details of a theory for searching for axions with germanium detectors were recently given by Creswick et al. [9]. The objective is to detect solar axions through their coherent Primakoff conversion into photons in the lattice of a germanium crystal when the incident angle satisfies the Bragg condition. The detection rates in various energy windows are correlated with the relative orientations of the detector and the sun [9]. This correlation results in a distinctive, unique signature of the axion. In this Letter, the results of a search using a 1 kg, ultralow background germanium detector installed in the HIPARSA iron mine in Sierra Grande, Argentina, at 410 24 00 S and 65 ± 22 0 W are presented. A description of the experimental setup and detector spectrum was given earlier by Di Gregori...

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To better understand the contribution of cosmic ray muons to the CUORICINO background, ten plastic scintillator detectors were installed at the CUORICINO site and operated during the final 3 months of the experiment. From these measurements, an upper limit of 0.0021 counts/(keV·kg·yr) (95% C.L.) was obtained on the cosmic ray induced background in the neutrinoless double beta decay region of interest. The measurements were also compared to Geant4 simulations.

It is assumed that axions exist and are created in the sun by Primakoff conversion of photons in the Coulomb fields of nuclei. Detection rates are calculated in germanium detectors due to the coherent conversion of axions to photons in the lattice when the incident angle fulfills the Bragg condition for a given crystalline plane. The rates are correlated with the relative positions of the sun and detector yielding a characteristic recognizable sub-diurnal temporal pattern. A major experiment is proposed based on a large detector array.

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The Majorana Demonstrator is an ultra low-background experiment searching for neutrinoless double-beta decay in 76 Ge. The heavily shielded array of germanium detectors, placed nearly a mile underground at the Sanford Underground Research Facility in Lead, South Dakota, also allows searches for new exotic physics. We present the first limits for tri-nucleon decay-specific modes and invisible decay modes for Ge isotopes. We find a half-life limit of 4.9 × 10 25 yr for the decay 76 Ge(ppn) → 73 Zn e + π + and 4.7 × 10 25 yr for the decay 76 Ge(ppp)→ 73 Cu e + π + π + . The half-life limit for the invisible tri-proton decay mode of 76 Ge was found to be 7.5 × 10 24 yr.

We report the first measurement of the total muon flux underground at the Davis Campus of the Sanford Underground Research Facility at the 4850 ft level. Measurements were performed using the Majorana Demonstrator muon veto system arranged in two different configurations. The measured total flux is (5.31 ± 0.17) × 10 −9 µ/s/cm 2 .