598 research outputs found

    Dark matter scenarios in a constrained model with Dirac gauginos

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    We perform the first analysis of Dark Matter scenarios in a constrained model with Dirac Gauginos. The model under investigation is the Constrained Minimal Dirac Gaugino Supersymmetric Standard model (CMDGSSM) where the Majorana mass terms of gauginos vanish. However, RR-symmetry is broken in the Higgs sector by an explicit and/or effective BμB_\mu-term. This causes a mass splitting between Dirac states in the fermion sector and the neutralinos, which provide the dark matter candidate, become pseudo-Dirac states. We discuss two scenarios: the universal case with all scalar masses unified at the GUT scale, and the case with non-universal Higgs soft-terms. We identify different regions in the parameter space which fullfil all constraints from the dark matter abundance, the limits from SUSY and direct dark matter searches and the Higgs mass. Most of these points can be tested with the next generation of direct dark matter detection experiments.Comment: 28 pages, 11 figures; v2: minor changes, title modified; matches published versio

    N-loop running should be combined with N-loop matching

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    We investigate the high-scale behaviour of Higgs sectors beyond the Standard Model, pointing out that the proper matching of the quartic couplings before applying the renormalisation group equations (RGEs) is of crucial importance for reliable predictions at larger energy scales. In particular, the common practice of leading-order parameters in the RGE evolution is insufficient to make precise statements on a given model's UV behaviour, typically resulting in uncertainties of many orders of magnitude. We argue that, before applying N-loop RGEs, a matching should even be performed at N-loop order in contrast to common lore. We show both analytical and numerical results where the impact is sizeable for three minimal extensions of the Standard Model: a singlet extension, a second Higgs doublet and finally vector-like quarks. We highlight that the known two-loop RGEs tend to moderate the running of their one-loop counterparts, typically delaying the appearance of Landau poles. For the addition of vector-like quarks we show that the complete two-loop matching and RGE evolution hints at a stabilisation of the electroweak vacuum at high energies, in contrast to results in the literature.Comment: 16 pages, 11 figures; v2: title changed, accepted for publication in PR

    Observation of Cosmic Acceleration and Determining the Fate of the Universe

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    Current observations of Type Ia supernovae provide evidence for cosmic acceleration out to a redshift of z \lsim 1, leading to the possibility that the universe is entering an inflationary epoch. However, inflation can take place only if vacuum-energy (or other sufficiently slowly redshifting source of energy density) dominates the energy density of a region of physical radius 1/H. We argue that for the best-fit values of ΩΛ\Omega_\Lambda and Ωm\Omega_m inferred from the supernovae data, one must confirm cosmic acceleration out to at least z1.8z \simeq 1.8 to infer that the universe is inflating.Comment: 4 pages;important changes in conclusion; published in Phys. Rev. Let

    Closure Report for Corrective Action Unit 566: EMAD Compound, Nevada National Security Site, Nevada with ROTC-1, Revision 0

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    This Closure Report (CR) presents information supporting the closure of Corrective Action Unit (CAU) 566: EMAD Compound, Nevada National Security Site, Nevada. Corrective Action Unit 566 comprises Corrective Action Site (CAS) 25-99-20, EMAD Compound, located within Area 25 of the Nevada National Security Site. The purpose of this CR is to provide documentation supporting the completed corrective actions and provide data confirming that the closure objectives for CAU 566 were met. To achieve this, the following actions were performed: • Review the current site conditions, including the concentration and extent of contamination. • Implement any corrective actions necessary to protect human health and the environment. • Properly dispose of corrective action and investigation wastes. • Document Notice of Completion and closure of CAU 566 issued by the Nevada Division of Environmental Protection. From October 2010 through May 2011, closure activities were performed as set forth in the Streamlined Approach for Environmental Restoration Plan for CAU 566: EMAD Compound, Nevada National Security Site, Nevada. The purposes of the activities as defined during the data quality objectives process were as follows: • Determine whether contaminants of concern (COCs) are present. • If COCs are present, determine their nature and extent, implement appropriate corrective actions, and properly dispose of wastes. Analytes detected during the closure activities were evaluated against final action levels (FALs) to determine COCs for CAU 566. Assessment of the data from collected soil samples, and from radiological and visual surveys of the site, indicates the FALs were exceeded for polychlorinated biphenyls (PCBs), semivolatile organic compounds (SVOCs), and radioactivity. Corrective actions were implemented to remove the following: • Radiologically contaminated soil assumed greater than FAL at two locations • Radiologically contaminated soil assumed greater than FAL with lead shot • PCB-contaminated soil • Radiologically contaminated filters and equipment • Fuels, lubricants, engine coolants, and oils • Lead debris • Electrical and lighting components assumed to be potential source materials, including - fluorescent light bulbs - mercury switches (thermostats) - circuit boards - PCB-containing ballasts Closure of CAU 566 was achieved through a combination of removal activities and closure in place. Corrective actions to remove COCs, and known and assumed potential source materials, were implemented as was practical. The PCBs remaining at the site are bounded laterally, but not vertically, within CAS 25-99-20 based upon step-out sampling; the sources (e.g., PCB transformer oils, diesel fuel from locomotive reservoirs) have been removed; the practice of the application of PCB-containing oils for soil stabilization has ceased; and the COCs are not readily mobile in the environment. Closure in place is necessary, and future land use of the site will be restricted from intrusive activities. This will effectively eliminate inadvertent contact by humans with the contaminated media. The DOE, National Nuclear Security Administration Nevada Site Office, provides the following recommendations: • No further corrective action is required at CAS 25-99-20. • Closure in place of CAS 25-99-20. • A use restriction is required at CAU 566. • A Notice of Completion to the DOE, National Nuclear Security Administration Nevada Site Office, is requested from the Nevada Division of Environmental Protection for closure of CAU 566. • Corrective Action Unit 566 should be moved from Appendix III to Appendix IV of the Federal Facility Agreement and Consent Order

    Addendum to the Corrective Action Decision Document/Closure Report for Corrective Action Unit 529: Area 25 Contaminated Materials, Nevada Test Site, Nevada, Revision 1

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    This document constitutes an addendum to the Corrective Action Decision Document/Closure Report for Corrective Action Unit 529: Area 25 Contaminated Materials, Nevada Test Site, Nevada as described in the document Recommendations and Justifications To Remove Use Restrictions Established under the U.S. Department of Energy, National Nuclear Security Administration Nevada Field Office Federal Facility Agreement and Consent Order dated September 2013. The Use Restriction (UR) Removal document was approved by the Nevada Division of Environmental Protection on October 16, 2013. The approval of the UR Removal document constituted approval of each of the recommended UR removals. In conformance with the UR Removal document, this addendum consists of: This page that refers the reader to the UR Removal document for additional information The cover, title, and signature pages of the UR Removal document The NDEP approval letter The corresponding section of the UR Removal document This addendum provides the documentation justifying the cancellation of the UR for CAS 25-23-17, Contaminated Wash (Parcel H). This UR was established as part of FFACO corrective actions and was based on the presence of total petroleum hydrocarbon diesel-range organics contamination at concentrations greater than the NDEP action level at the time of the initial investigation

    Addendum to the Closure Report for Corrective Action Unit 165: Area 25 and 26 Dry Well and Washdown Areas, Nevada Test Site, Nevada, Revision 0

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    This document constitutes an addendum to the Closure Report for Corrective Action Unit 165: Area 25 and 26 Dry Well and Washdown Areas, Nevada Test Site, Nevada as described in the document Recommendations and Justifications To Remove Use Restrictions Established under the U.S. Department of Energy, National Nuclear Security Administration Nevada Field Office Federal Facility Agreement and Consent Order dated September 2013. The Use Restriction Removal document was approved by the Nevada Division of Environmental Protection on October 16, 2013. The approval of the UR Removal document constituted approval of each of the recommended UR removals. In conformance with the UR Removal document, this addendum consists of: This page that refers the reader to the UR Removal document for additional information The cover, title, and signature pages of the UR Removal document The NDEP approval letter The corresponding section of the UR Removal document This addendum provides the documentation justifying the cancellation of the UR for CAS 25-20-01, Lab Drain Dry Well. This UR was established as part of FFACO corrective actions and was based on the presence of tetrachloroethene contamination at concentrations greater than the action level established at the time of the initial investigation. Although total petroleum hydrocarbon diesel-range organics contamination at concentrations greater than the NDEP action level was present at the site, no hazardous constituents of TPH-DRO exceeded the U.S. Environmental Protection Agency (EPA) Region 9 preliminary remediation goals established at the time of the initial investigation

    LION Navigator for Transfer to GEO Using Electric Propulsion

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    GNSS space receivers are widely used for onboard auton-omous navigation of spacecraft platforms in low Earth orbit. Navigation by GNSS up to geosynchronous altitude was made possible through the introduction of a Space Service Volume which defines signal strength up to geo-synchronous altitude. For Galileo, similar definitions are under consideration. On this basis onboard autonomous navigation for commercial communication satellites be-came a realistic possibility, too. Transfer to geostationary orbit is still fully depending on classical RF tracking by ground station for orbit determination. With electrical propulsion, the transfer duration extends to several months. As a consequence onboard autonomous naviga-tion by satellite navigation has become of commercial interest. A GNSS navigation receiver on a spacecraft on transfer orbit has to cope with extreme signal conditions from very low (at perigee) to very high (at super-synchronous apogee) altitude, which is far above the constellation satellites. At this altitude only very rare and weak signals that spill over the limb of the earth can be used. An addi-tional difficulty is the varying spacecraft orientation which is not nadir pointing, as is commonly assumed, but is varying according to the demands of optimal attitude guidance laws and power requirements. By using both GPS and Galileo together the availability of navigation signals is increased. The paper describes the design process to determine basic parameters e.g. number and orientation of receive anten-nas, receiver parameters like C/N0 thresholds, and naviga-tion procedures. Detailed simulations are presented for selected parts of the transfer arc using verified models of the navigation receiver. Finally the geostationary transfer capabilities of the space-borne LION Navigator GNSS receiver are demon-strated in a closed-loop real time test environment under RF stimulation

    Precision tools and models to narrow in on the 750 GeV diphoton resonance

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    The hints for a new resonance at 750 GeV from ATLAS and CMS have triggered a significant amount of attention. Since the simplest extensions of the standard model cannot accommodate the observation, many alternatives have been considered to explain the excess. Here we focus on several proposed renormalisable weakly-coupled models and revisit results given in the literature. We point out that physically important subtleties are often missed or neglected. To facilitate the study of the excess we have created a collection of 40 model files, selected from recent literature, for the Mathematica package SARAH. With SARAH one can generate files to perform numerical studies using the tailor-made spectrum generators FlexibleSUSY and SPheno. These have been extended to automatically include crucial higher order corrections to the diphoton and digluon decay rates for both CP-even and CP-odd scalars. Additionally, we have extended the UFO and CalcHep interfaces of SARAH, to pass the precise information about the effective vertices from the spectrum generator to a Monte-Carlo tool. Finally, as an example to demonstrate the power of the entire setup, we present a new supersymmetric model that accommodates the diphoton excess, explicitly demonstrating how a large width can be obtained. We explicitly show several steps in detail to elucidate the use of these public tools in the precision study of this model.Comment: 184 pages, 24 figures; model files available at http://sarah.hepforge.org/Diphoton_Models.tar.gz; v2: added a few clarifications and reference

    Record of Technical Change 1 for Closure Report for Corrective Action Unit 204: Storage Bunkers, Nevada Test Site, Nevada, Revision 0

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    Downgrade FFACO UR at CAU 204, CAS 05-33-01, Kay Blockhouse to an Administrative UR
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