1767124
Search for weakly interacting massive particles with the first five-tower data from the cryogenic dark matter search at the soudan underground laboratory.
We report results from the Cryogenic Dark Matter Search at the Soudan Underground Laboratory (CDMS II) featuring the full complement of 30 detectors. A blind analysis of data taken between October 2006 and July 2007 sets an upper limit on the weakly interacting massive particle (WIMP) nucleon spin-independent cross section of 6.6x10;{-44} cm;{2} (4.6x10;{-44} cm;{2} when combined with previous CDMS II data) at the 90% confidence level for a WIMP mass of 60 GeV/c;{2}. This achieves the best sensitivity for dark matter WIMPs with masses above 44 GeV/c;{2}, and significantly restricts the parameter space for some favored supersymmetric models.
6288625
Combined limits on WIMPs from the CDMS and EDELWEISS experiments
The CDMS and EDELWEISS collaborations have combined the results of their direct searches for dark matter using cryogenic germanium detectors. The total data set represents 614  kg·days equivalent exposure. A straightforward method of combination was chosen for its simplicity before data were exchanged between experiments. The results are interpreted in terms of limits on spin-independent weakly interacting, massive particle (WIMP)-nucleon cross section. For a WIMP mass of 90  GeV/c^2, where this analysis is most sensitive, a cross section of 3.3×10^(-44)  cm^2 is excluded at 90% C.L. At higher WIMP masses, the combination improves the individual limits, by a factor 1.6 above 700  GeV/c^2. Alternative methods of combining the data provide stronger constraints for some ranges of WIMP masses and weaker constraints for others.
123537479
Report on Stanford Superconductive Monopole Detectors
Since January, 1983 we have been operating a three loop superconducting detector with a signal to noise ratio of 100 for the direct detection of Dirac magnetic charges.1 Its sensing area averaged over solid angle is nearly 500 cm2 for double coincidence events. To date, the data contain no candidate events and set an upper flux limit of 2 × 10−11 cm−2 s−1 sr−1 at 90% C.L., 70 times lower than that suggested by the single candidate event2 seen on the prototype single loop detector. If supermassive magnetic monopoles exist they are rare and the need for cost-efficient larger area superconductive detectors is evident if we are to push forward a definitive search in the cosmic rays. Superconducting loop detectors can be constructed with 1 to 10 m2 planar areas coupled to a single SQUID while achieving a signal to noise ratio of 10 for the detection of a Dirac magnetic charge. A 100 m2 sensing area array of such detectors, which would reach the Parker flux bound in one year of operation, can be built at a cost comparable to that of typical high energy experiments. It remains quite possible that a monopole particle flux significantly higher than the Parker bound exists within our galaxy. In this paper the most recent results from low noise operation of the three loop detector are presented. Also discussed are our plans to build a larger fixed loop detector with a sensing area of 1.5 m2. It is designed as a prototype for a future yet larger 100 m2 array.
45565394
Limit on the flux of cosmic-ray magnetic monopoles from operation of an eight-loop superconducting detector.
An eight-loop superconducting magnetic monopole detector has been in continuous operation for 547 days, starting 4 March 1987. Its sensing area is 1.1 m{sup 2} for double-coincident events. The data, which contain no candidate events, set an upper limit of 7.2{times}10{sup {minus}13} cm{sup {minus}2} s{sup {minus}1} sr{sup {minus}1} (90% confidence level) on the flux of monopoles of any mass and at any velocity passing through the Earth's surface.
4989217
Low-threshold analysis of CDMS shallow-site data
Data taken during the final shallow-site run of the first tower of the Cryogenic Dark Matter Search (CDMS II) detectors have been reanalyzed with improved sensitivity to small energy depositions. Four {approx}224 g germanium and two {approx}105 g silicon detectors were operated at the Stanford Underground Facility (SUF) between December 2001 and June 2002, yielding 118 live days of raw exposure. Three of the germanium and both silicon detectors were analyzed with a new low-threshold technique, making it possible to lower the germanium and silicon analysis thresholds down to the actual trigger thresholds of {approx}1 and {approx}2 keV, respectively. Limits on the spin-independent cross section for weakly interacting massive particles (WIMPs) to elastically scatter from nuclei based on these data exclude interesting parameter space for WIMPs with masses below 9 GeV/c{sup 2}. Under standard halo assumptions, these data partially exclude parameter space favored by interpretations of the DAMA/LIBRA and CoGeNT experiments data as WIMP signals, and exclude new parameter space for WIMP masses between 3 and 4 GeV/c{sup 2}.
35488270
Search for inelastic dark matter with the CDMS II experiment
Results are presented from a reanalysis of the entire five-tower data set acquired with the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory, with an exposure of 969 kg-days. The analysis window was extended to a recoil energy of 150 keV, and an improved surface-event background-rejection cut was defined to increase the sensitivity of the experiment to the inelastic dark matter (iDM) model. Three dark matter candidates were found between 25 keV and 150 keV. The probability to observe three or more background events in this energy range is 11%. Because of the occurrence of these events, the constraints on the iDM parameter space are slightly less stringent than those from our previous analysis, which used an energy window of 10-100 keV. © 2011 American Physical Society.
119089791
Searching for Variability in the Globular Cluster Messier 4
Time-series data taken with the Hubble Space Telescope of a field six core radii (~5') from the center of the globular cluster Messier 4, and covering a period of about 10 weeks in early 2001, have been analyzed in search of variable objects. Various criteria were employed to select candidate variable stars. Period searches were performed on the selected candidates using phase dispersion minimization (PDM). The reliability of the PDM search results was tested using synthetic light curves of eclipsing binary stars and sinusoidal light curves of different periods. Results from this analysis showed that there are probably no eclipsing binary stars or periodic variables in our field with periods on the order of a few hours to a few days, down to limiting magnitudes of V ~ 25 and I ~ 24, which is consistent with the absence of contact binaries such as W Ursae Majoris systems. However, one candidate variable star does show an increase in brightness of ~0.1 mag in both bandpasses, which seems to last for a few days. Possible explanations concerning the nature of this object include a binary system with a white dwarf primary and a low-mass main-sequence secondary or a BY Draconis variable star. We are able to set an upper limit to the observed fraction of photometric variability in this data set of 0.05%.
117129613
On the Analytic Structure of Scalar Glueball Operators
The correlator of the square of the Yang-Mills field-strength tensor corresponds to a scalar glueball, i.e., to a bound-state formed by gluonic ingredients only. It has quantum numbers 0++ and its mass, as predicted by different theoretical approaches, is expected to lie between 1 and 2 GeV. Here we restrict our considerations to the Born level, that is, we consider the correlator to zeroth order in the coupling. Gluonic self-interaction is taken into account indirectly by using non-perturbative gluon propagators. The employed closed expressions are motivated by lattice and Dyson-Schwinger studies. The analytic continuation of the integrals themselves is complicated by additional obstructive structures like branch cuts and poles that are induced by the inner integral in the complex plane of the outer integration variable. We deal with this problem by deforming the outer integration contour accordingly. For different input gluon propagators we find a positive glueball spectral density which is required for physical states. Poles are, however, absent which is most likely an artifact of working at Born level.
118425953
Gluonic three-point correlations in pure Landau gauge QCD
We report on the first self-consistent solution of the Dyson-Schwinger equation (DSE) for the three-gluon vertex. Based on earlier results for the propagators which match data from lattice Monte-Carlo simulations, we obtain results for the three-gluon vertex that are in very good agreement with available lattice data likewise. Feeding these results back into the propagator DSEs leads to some changes especially in the gluon propagator. These changes allow us to assess previously used models for the three-gluon vertex and to systematically estimate the influence of neglected two-loop diagrams with four-gluon interactions. In the final step, a full iterative solution to the coupled DSEs of pure Landau gauge QCD without quarks is then obtained for the first time in an extended truncation which now dynamically includes the complete set of three-point vertex functions.
119438179
Central and noncentral components of the effective sd-shell interaction
The contributions of central as well as noncentral two-body interactions to the matrix elements of various effective interactions for the $\mathrm{sd}$ shell are studied in an SU(3) two-particle basis. The results show that their central parts agree rather well and exhibit an approximate SU(3) symmetry. However, large differences are found between the noncentral parts of microscopic and phenomenological interactions, respectively. The influence of noncentral components of the matrix elements of Glaudemans et al. on experimental data is investigated for the case of $^{28}\mathrm{Si}$, with the result that the $\mathrm{LS}$ component is very important to reproduce the correct ground state binding energy. Some effects introduced by higher order two-body interactions and many-body interactions are discussed.
7124426
Color and Variability Characteristics of Point Sources in the Faint Sky Variability Survey
We present an analysis of the color and variability characteristics for point sources in the Faint Sky Variability Survey (FSVS). The FSVS cataloged ~23 deg2 in BVI filters from ~16 to 24 mag to investigate variability in faint sources at moderate-to-high Galactic latitudes. Point-source completeness is found to be >83% for a selected representative sample (V = 17.5-22.0 mag, B - V = 0.0-1.5) containing both photometric B, V detections and 80% of the time-sampled V data available compared to a basic internal source completeness of 99%. Multiepoch (10-30) observations in V spanning minutes to years modeled by light-curve simulations reveal amplitude sensitivities to ~0.015-0.075 mag over a representative V = 18-22 mag range. Periodicity determinations appear viable to timescales of order 1 day or less using the most sampled fields (~30 epochs). The fraction of point sources is found to be generally variable at 5%-8% over V = 17.5-22.0 mag. For V brighter than 19 mag, the variable population is dominated by low-amplitude (<0.05 mag) and blue (B - V < 0.35) sources, possibly representing a population of γ Doradus stars. Overall, the dominant population of variable sources are bluer than B - V = 0.65 and have main-sequence colors, likely reflecting larger populations of RR Lyrae, SX Phe, γ Doradus, and W UMa variables.