Trileptons from Chargino-Neutralino Production at the CERN Large Hadron Collider

We study direct production of charginos and neutralinos at the CERN Large Hadron Collider. We simulate all channels of chargino and neutralino production using ISAJET 7.07. The best mode for observing such processes appears to be pp\to\tw_1\tz_2\to 3\ell +\eslt. We evaluate signal expectations and background levels, and suggest cuts to optimize the signal. The trilepton mode should be viable provided m_{\tg}\alt 500-600~GeV; above this mass, the decay modes \tz_2\to\tz_1 Z and \tz_2\to H_{\ell}\tz_1 become dominant, spoiling the signal. In the first case, the leptonic branching fraction for $Z$ decay is small and additional background from $WZ$ is present, while in the second case, the trilepton signal is essentially absent. For smaller values of $m_{\tg}$, the trilepton signal should be visible above background, especially if $|\mu|\simeq m_{\tg}$ and m_{\tell}\ll m_{\tq}, in which case the leptonic decays of \tz_2 are enhanced. Distributions in dilepton mass $m(\ell\bar{\ell})$ can yield direct information on neutralino masses due to the distribution cutoff at m_{\tz_2}-m_{\tz_1}. Other distributions that may lead to an additional constraint amongst the chargino and neutralino masses are also examined.Comment: preprint nos. FSU-HEP-940310 and UH-511-786-94, 13 pages (REVTEX) plus 7 uuencoded figures attache

The design and implementation of a meaning driven data query language

We present the design and implementation of a Meaning Driven Data Query Language - MDDQL - which aims at the construction of queries through system made suggestions of natural language based query terms for both scientific application domain terms and operator/operation ones. A query construction blackboard is used where query language terms are suggested to the user in its preferred natural language and in a name centered way, together with their connotation. This helps in understanding the meaning of the terms and/or operators or operations to be included in the query. Furthermore, the construction of the query turns out to be an incremental refinement of the query under construction through semantic constraints, where only those domain language terms and/or operators/operations are suggested which result into meaningful combinations of query terms as related to the scientific application domain semantics. Therefore, semantically meaningless queries can be prevented during the query construction. Such a semantics aware mechanism is not available in conventional database query languages such as SQL, where one is allowed to execute a query calculating, for example, the average of numerical data values whereas they represent the codes of categorical values. Moreover, no familiarity with the semantics of complex database schemes or interpretation of the symbols (names of classes/tables/attributes, value codes) underlying the storage model, as well as familiarity with the syntax of a database specific query language are needed by the end-user. The constructed query can be submitted to the MDDQL query interpretation and transformation engine, where the corresponding SQL-query is generated and delegated to a DBMS (e.g., Oracle, MSAccess, SQL-Server). Generation of SQL-statements addressing NF2 data models such as those provided by the object-relational Oracle DBMS is also enabled. The query result is presented in a table based form where all storage model symbols are interpreted and can be exported for the usage with statistical software packages (e.g., SPSS)

Assessment of flywheel energy storage for spacecraft power systems

The feasibility of inertial energy storage in a spacecraft power system is evaluated on the basis of a conceptual integrated design that encompasses a composite rotor, magnetic suspension, and a permanent magnet (PM) motor/generator for a 3-kW orbital average payload at a bus distribution voltage of 250 volts dc. The conceptual design, which evolved at the Goddard Space Flight Center (GSFC), is referred to as a Mechanical Capacitor. The baseline power system configuration selected is a series system employing peak-power-tracking for a Low Earth-Orbiting application. Power processing, required in the motor/generator, provides a potential alternative configurations that can only be achieved in systems with electrochemical energy storage by the addition of power processing components. One such alternative configuration provides for peak-power-tracking of the solar array and still maintains a regulated bus, without the expense of additional power processing components. Precise speed control of the two counterrotating wheels is required to reduce interaction with the attitude control system (ACS) or alternatively, used to perform attitude control functions. Critical technologies identified are those pertaining to the energy storage element and are prioritized as composite wheel development, magnetic suspension, motor/generator, containment, and momentum control. Comparison with a 3-kW, 250-Vdc power system using either NiCd or NiH2 for energy storage results in a system in which inertial energy storage offers potential advantages in lifetime, operating temperature, voltage regulation, energy density, charge control, and overall system weight reduction

Neutralino, axion and axino cold dark matter in minimal, hypercharged and gaugino AMSB

Supersymmetric models based on anomaly-mediated SUSY breaking (AMSB) generally give rise to a neutral wino as a WIMP cold dark matter (CDM) candidate, whose thermal abundance is well below measured values. Here, we investigate four scenarios to reconcile AMSB dark matter with the measured abundance: 1. non-thermal wino production due to decays of scalar fields ({\it e.g} moduli), 2. non-thermal wino production due to decays of gravitinos, 3. non-thermal wino production due to heavy axino decays, and 4. the case of an axino LSP, where the bulk of CDM is made up of axions and thermally produced axinos. In cases 1 and 2, we expect wino CDM to constitute the entire measured DM abundance, and we investigate wino-like WIMP direct and indirect detection rates. Wino direct detection rates can be large, and more importantly, are bounded from below, so that ton-scale noble liquid detectors should access all of parameter space for m_{\tz_1}\alt 500 GeV. Indirect wino detection rates via neutrino telescopes and space-based cosmic ray detectors can also be large. In case 3, the DM would consist of an axion plus wino admixture, whose exact proportions are very model dependent. In this case, it is possible that both an axion and a wino-like WIMP could be detected experimentally. In case 4., we calculate the re-heat temperature of the universe after inflation. In this case, no direct or indirect WIMP signals should be seen, although direct detection of relic axions may be possible. For each DM scenario, we show results for the minimal AMSB model, as well as for the hypercharged and gaugino AMSB models.Comment: 29 pages including 13 figure

MDDQL-Stat: data querying and analysis through integration of intentional and extensional semantics

We would like to present a prototype system enabling a rather empirical than a formal approach to the problem of posing queries to a semantically rich (quality aspects, semantic distance, etc.) data integration system {G,S,M} (Global schema, Sources, Mediation) through integration not only of intensional but also of extensional semantics. While the first is provided by an alphabet Ag, as given by an ontology based global schema G, and a high level query language (conjunction/disjunction + inequalities + statistical operations), the latter enables synthesizing of data source specific and previously transformed query results according to well-defined set operations for heterogeneous, distributed data sources. Our approach contrasts with other GAV (Global-As-View) related architectures for mediation of integrated read-only views, in that it simplifies query processing while preserving flexibility when adding new data sources, despite the inherited complexity of mappings due to enhanced semantic description of data (semantic distance, quality parameters, etc.) such that statistical results and comparisons become more meaningful

Hidden SUSY at the LHC: the light higgsino-world scenario and the role of a lepton collider

While the SUSY flavor, CP and gravitino problems seem to favor a very heavy spectrum of matter scalars, fine-tuning in the electroweak sector prefers low values of superpotential mass \mu. In the limit of low \mu, the two lightest neutralinos and light chargino are higgsino-like. The light charginos and neutralinos may have large production cross sections at LHC, but since they are nearly mass degenerate, there is only small energy release in three-body sparticle decays. Possible dilepton and trilepton signatures are difficult to observe after mild cuts due to the very soft p_T spectrum of the final state isolated leptons. Thus, the higgsino-world scenario can easily elude standard SUSY searches at the LHC. It should motivate experimental searches to focus on dimuon and trimuon production at the very lowest p_T(\mu) values possible. If the neutralino relic abundance is enhanced via non-standard cosmological dark matter production, then there exist excellent prospects for direct or indirect detection of higgsino-like WIMPs. While the higgsino-world scenario may easily hide from LHC SUSY searches, a linear e^+e^- collider or a muon collider operating in the \sqrt{s}\sim 0.5-1 TeV range would be able to easily access the chargino and neutralino pair production reactions.Comment: 20 pages including 12 .eps figure

A semantics based interactive query formulation technique

We present an interactive query formulation technique which enables exploitation not only of structural properties of data but also of semantic constraints as posed by the contents of data. The technique aims at the formulation of a semantically consistent or meaningful query by the end-user without any previous knowledge of syntax formalisms and data model semantics. This has been achieved by end-user guidance in that an inference engine suggests semantically rich query terms for further consideration by the end-user. The set of suggested terms at each interaction stage comply with the already considered query terms with respect to structure and contents based semantics. Assignment or selection of operational terms are also allowed, if operational semantics comply with the semantics of data. The interactive query formulation component has been implemented in Java and runs on the client side of a client/server based query answering system architecture

Neutralino dark matter in mSUGRA/CMSSM with a 125 GeV light Higgs scalar

The minimal supergravity (mSUGRA or CMSSM) model is an oft-used framework for exhibiting the properties of neutralino (WIMP) cold dark matter (CDM). However, the recent evidence from Atlas and CMS on a light Higgs scalar with mass m_h\simeq 125 GeV highly constrains the superparticle mass spectrum, which in turn constrains the neutralino annihilation mechanisms in the early universe. We find that stau and stop co-annihilation mechanisms -- already highly stressed by the latest Atlas/CMS results on SUSY searches -- are nearly eliminated if indeed the light Higgs scalar has mass m_h\simeq 125 GeV. Furthermore, neutralino annihilation via the A-resonance is essentially ruled out in mSUGRA so that it is exceedingly difficult to generate thermally-produced neutralino-only dark matter at the measured abundance. The remaining possibility lies in the focus-point region which now moves out to m_0\sim 10-20 TeV range due to the required large trilinear soft SUSY breaking term A_0. The remaining HB/FP region is more fine-tuned than before owing to the typically large top squark masses. We present updated direct and indirect detection rates for neutralino dark matter, and show that ton scale noble liquid detectors will either discover mixed higgsino CDM or essentially rule out thermally-produced neutralino-only CDM in the mSUGRA model.Comment: 17 pages including 9 .eps figure