67820728
Beyond the CDMS-II Dark Matter Search: SuperCDMS
Department of Physics, Santa Clara University, Santa Clara, CA 95053, USAPresently the CDMS-II collaboration’s Weakly Interacting Massive Particle (WIMP) search at theSoudan Underground Laboratory sets the most stringent exclusion limits of any WIMP cold darkmatter direct-detection experiment. To extend our reach further, to WIMP-nucleon cross sectionsin the range 10
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.
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.
56569059
Search for annual modulation in low-energy CDMS-II data
We report limits on annual modulation of the low-energy event rate from the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory. Such a modulation could be produced by interactions from Weakly Interacting Massive Particles (WIMPs) with masses ~10 GeV/c^2. We find no evidence for annual modulation in the event rate of veto-anticoincident single-detector interactions consistent with nuclear recoils, and constrain the magnitude of any modulation to 98% confidence. For events consistent with electron recoils, no significant modulation is observed for either single- or multiple-detector interactions in the 3.0-7.4 keVee range.
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.
119221664
X-ray selected galaxy clusters in the Pan-STARRS Medium Deep Survey
We present the results of a pilot study for the extended Massive Cluster Survey (eMACS), a comprehensive search for distant, X-ray luminous galaxy clusters at z > 0.5. Our pilot study applies the eMACS concept to the 71 deg2 area extended by the 10 fields of the Pan-STARRS1 (PS1) Medium Deep Survey (MDS). Candidate clusters are identified by visual inspection of PS1 images in the g, r, i and z bands in a 5 × 5 arcmin2 region around X-ray sources detected in the ROSAT All-Sky Survey (RASS). To test and optimize the eMACS X-ray selection criteria, our pilot study uses the largest possible RASS data base, i.e. all RASS sources listed in the Bright and Faint Source Catalogues (BSC and FSC) that fall within the MDS footprint. We apply no additional constraints regarding X-ray flux, spectral hardness ratio or photon statistics and lower the redshift threshold to z > 0.3 to extend the probed luminosity range to poorer systems. Scrutiny of PS1/MDS images for 41 BSC and 200 FSC sources combined with dedicated spectroscopic follow-up observations results in a sample of 11 clusters with estimated or spectroscopic redshifts of z > 0.3. In order to assess and quantify the degree of point source contamination of the observed RASS fluxes, we examine archival Chandra data obtained in targeted and serendipitous observations of six of the 11 clusters found. As expected, the diffuse emission from all six systems is contaminated by point sources to some degree, and for half of them active galactic nucleus emission dominates. X-ray follow-up observations will thus be crucial in order to establish robust cluster luminosities for eMACS clusters. Although the small number of distant X-ray luminous clusters in the MDS does not allow us to make firm predictions for the over 20 000 deg2 of extragalactic sky covered by eMACS, the identification of two extremely promising eMACS cluster candidates at z ≳ 0.6 (both yet to be observed with Chandra) in such a small solid angle is encouraging. Representing a tremendous gain over the presently known two dozen such systems from X-ray, optical and Sunyaev–Zel’dovich cluster surveys combined, the sample of over 100 extremely massive clusters at z > 0.5 expected from eMACS would be invaluable for the identification of the most powerful gravitational lenses in the Universe, as well as for in-depth and statistical studies of the physical properties of the most massive galaxy clusters out to z ∼ 1.
14488159
Algorithmic derivation of functional renormalization group equations and Dyson-Schwinger equations
We present the Mathematica application DoFun 1 which allows to derive Dyson-Schwinger equations and renormalization group ow equations for n-point functions in a simple manner. DoFun oers several tools which considerably simplify the derivation of these equations from a given physical action. We discuss the application of DoFun by means of two dierent types of quantum eld
6360592
Measuring the neutron's mean square charge radius using neutron interferometry
Abstract The neutron is electrically neutral, but its substructure consists of charged quarks so it may have an internal charge distribution. In fact it is known to have a negative mean square charge radius (MSCR), the second moment of the radial charge density. In other words the neutron has a positive core and negative skin. In the first Born approximation the neutron MSCR can be simply related to the neutron–electron scattering length b ne . In the past this important quantity has been extracted from the energy dependence of the total transmission cross-section of neutrons on high-Z targets, a very difficult and complicated process. A few years ago S.A. Werner proposed a novel approach to measuring b ne from the neutron's dynamical phase shift in a perfect crystal close to the Bragg condition. We are conducting an experiment based on this method at the NIST neutron interferometer which may lead to a five-fold improvement in precision of b ne and hence the neutron MSCR.
119092260
Relativistic entanglement of two massive particles
We describe the spin and momentum degrees of freedom of a system of two massive spin-(1/2) particles as a four-qubit system. Then we explicitly show how the entanglement changes between different partitions of the qubits, when considered by different inertial observers. Although the two particle entanglement corresponding to a partition into Alice's and Bob's subsystems is, as often stated in the literature, invariant under Lorentz boosts, the entanglement with respect to other partitions of the Hilbert space on the other hand, is not. It certainly does depend on the chosen inertial frame and on the initial state considered. The change of entanglement arises, because a Lorentz boost on the momenta of the particles causes a Wigner rotation of the spin, which in certain cases entangles the spin with the momentum states. We systematically investigate the situation for different classes of initial spin states and different partitions of the four-qubit space. Furthermore, we study the behavior of Bell inequalities for different observers and demonstrate how the maximally possible degree of violation, using the Pauli-Lubanski spin observable, can be recovered by any inertial observer.
121918725
Meson-nucleus interaction - on the use of intensive meson beams for subnuclear research -
Abstract The use of intensive pion and kaon beams for subnuclear research is discussed. The goals of such investigations are briefly sketched and illustrated for some typical examples of specific flavour transfer reactions. It turns out that the meson beams which will be available at the proposed EHF will open up a new aera of subnuclear research. Such investigation touch upon quite fundamental questions of hadronic physics.