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Search Results: 1 - 10 of 144183 matches for " B. Ostdiek "
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The Least Supersymmetric Signals at the LHC
de Blas, J.;Delgado, A.;Ostdiek, B.
High Energy Physics - Phenomenology , 2013,
Abstract: We study the implications at the LHC for the minimal (least) version of the supersymmetric standard model. In this model supersymmetry is broken by gravity and extra gauge interactions effects, providing a spectrum similar in several aspects to that in natural supersymmetric scenarios. Having the first two generations of sparticles partially decoupled means that any significant signal can only involve gauginos and the third family of sfermions. In practice, the signals are dominated by gluino production with subsequent decays into the stop sector. As we show, for gluino masses below 2300 GeV, a discovery at the LHC is possible at \sqrt{s}=14 TeV, but will require large integrated luminosities.
The Least Supersymmetric Signals at the LHC
J. de Blas,A. Delgado,B. Ostdiek
Physics , 2013, DOI: 10.1103/PhysRevD.87.115026
Abstract: We study the implications at the LHC for the minimal (least) version of the supersymmetric standard model. In this model supersymmetry is broken by gravity and extra gauge interactions effects, providing a spectrum similar in several aspects to that in natural supersymmetric scenarios. Having the first two generations of sparticles partially decoupled means that any significant signal can only involve gauginos and the third family of sfermions. In practice, the signals are dominated by gluino production with subsequent decays into the stop sector. As we show, for gluino masses below 2300 GeV, a discovery at the LHC is possible at \sqrt{s}=14 TeV, but will require large integrated luminosities.
Constraining the minimal dark matter fiveplet with LHC searches
Bryan Ostdiek
Physics , 2015, DOI: 10.1103/PhysRevD.92.055008
Abstract: Adding a fermion to the standard model particle content which is a fiveplet under $SU(2)_L$ gives a dark matter candidate. The lightest state in the multiplet is neutral and automatically stable. The charged component of the multiplet is only slightly heavier and can travel a finite distance in the LHC detectors before decaying, leaving a charged track which disappears before the edge of the detector. We use the recent ATLAS and CMS searches to exclude a Majorana fiveplet with a mass up to 267 GeV. We estimate that with 3 ab$^{-1}$ of $\sqrt{s}=14$ TeV data this could be pushed to a mass 520 GeV. These exclusions are $\sim 10\%$ greater than what is achieved for wino-like dark matter. We also discuss how the doubly charged states could be used to distinguish a disappearing track signal from that given by a triplet such as the pure wino.
Catching sparks from well-forged neutralinos
Joseph Bramante,Antonio Delgado,Fatemeh Elahi,Adam Martin,Bryan Ostdiek
Physics , 2014, DOI: 10.1103/PhysRevD.90.095008
Abstract: In this paper we present a new search technique for electroweakinos, the superpartners of electroweak gauge and Higgs bosons, based on final states with missing transverse energy, a photon, and a dilepton pair, $\ell^+\,\ell^- + \gamma + \displaystyle{\not} E_T$. Unlike traditional electroweakino searches, which perform best when $m_{\widetilde{\chi}^0_{2,3}} - m_{\widetilde{\chi}^0_1}, m_{\widetilde{\chi}^{\pm}} - m_{\widetilde{\chi}^0_1} > m_Z$, our search favors nearly degenerate spectra; degenerate electroweakinos typically have a larger branching ratio to photons, and the cut $m_{\ell\ell} \ll m_Z$ effectively removes on-shell Z boson backgrounds while retaining the signal. This feature makes our technique optimal for `well-tempered' scenarios, where the dark matter relic abundance is achieved with inter-electroweakino splittings of $\sim 20 - 70\,\text{GeV}$. Additionally, our strategy applies to a wider range of scenarios where the lightest neutralinos are almost degenerate, but only make up a subdominant component of the dark matter -- a spectrum we dub `well-forged'. Focusing on bino-Higgsino admixtures, we present optimal cuts and expected efficiencies for several benchmark scenarios. We find bino-Higgsino mixtures with $m_{\widetilde{\chi}^0_{2,3}} \lesssim 190\,\text{GeV}$ and $m_{\widetilde{\chi}^0_{2,3}} - m_{\widetilde{\chi}^0_1} \cong 30\,\text{GeV}$ can be uncovered after roughly $600\,\text{fb}^{-1}$ of luminosity at the 14 TeV LHC. Scenarios with lighter states require less data for discovery, while scenarios with heavier states or larger mass splittings are harder to discriminate from the background and require more data. Unlike many searches for supersymmetry, electroweakino searches are one area where the high luminosity of the next LHC run, rather than the increased energy, is crucial for discovery.
Measurement of the 33S(α,p)36Cl cross section: Implications for production of 36Cl in the early Solar System
Matthew Bowers,Yoav Kashiv,William Bauder,Mary Beard,Philippe Collon,Wenting Lu,Karen Ostdiek,Daniel Robertson
Physics , 2013, DOI: 10.1103/PhysRevC.88.065802
Abstract: Short-lived radionuclides (SLRs) with lifetimes \tau < 100 Ma are known to have been extant when the Solar System formed over 4.5 billion years ago. Identifying the sources of SLRs is important for understanding the timescales of Solar System formation and processes that occurred early in its history. Extinct 36Cl (t_1/2 = 0.301 Ma) is thought to have been produced by interaction of solar energetic particles (SEPs), emitted by the young Sun, with gas and dust in the nascent Solar System. However, models that calculate SLR production in the early Solar System (ESS) lack experimental data for the 36Cl production reactions. We present here the first measurement of the cross section of one of the main 36Cl production reactions, 33S(\alpha,p)36Cl, in the energy range 0.70 - 2.42 MeV/A. The cross section measurement was performed by bombarding a target and collecting the recoiled 36Cl atoms produced in the reaction, chemically processing the samples, and measuring the 36Cl/Cl ratio of the activated samples with accelerator mass spectrometry (AMS). The experimental results were found to be systematically higher than the cross sections used in previous local irradiation models and other Hauser-Feshbach calculated predictions. However, the effects of the experimentally measured cross sections on the modeled production of 36Cl in the early Solar System were found to be minimal. Reactions channels involving S targets dominate 36Cl production, but the astrophysical event parameters can dramatically change each reactions' relative contribution.
The Relic Neutralino Surface at a 100 TeV collider
Joseph Bramante,Patrick J. Fox,Adam Martin,Bryan Ostdiek,Tilman Plehn,Torben Schell,Michihisa Takeuchi
Physics , 2014, DOI: 10.1103/PhysRevD.91.054015
Abstract: We map the parameter space for MSSM neutralino dark matter which freezes out to the observed relic abundance, in the limit that all superpartners except the neutralinos and charginos are decoupled. In this space of relic neutralinos, we show the dominant dark matter annihilation modes, the mass splittings among the electroweakinos, direct detection rates, and collider cross-sections. The mass difference between the dark matter and the next-to-lightest neutral and charged states is typically much less than electroweak gauge boson masses. With these small mass differences, the relic neutralino surface is accessible to a future 100 TeV hadron collider, which can discover inter-neutralino mass splittings down to 1 GeV and thermal relic dark matter neutralino masses up to 1.5 TeV with a few inverse attobarns of luminosity. This coverage is a direct consequence of the increased collider energy: the Standard Model events with missing transverse momentum in the TeV range have mostly hard electroweak radiation, distinct from the soft radiation shed in compressed electroweakino decays. We exploit this kinematic feature in final states including photons and leptons, tailored to the 100 TeV collider environment.
Improved phenomenological description of equilibrium charge state distributions for Ni, Co, and Cu ions in Mo based on new experimental data at 2 MeV/u
P. Gastis,G. Perdikakis,D. Robertson,R. Almus,T. Anderson,W. Bauder,P. Collon,W. Lu,K. Ostdiek,M. Skulski
Physics , 2015,
Abstract: Equilibrium charge state distributions of stable 60Ni, 59Co, and 63Cu beams passing through a 1um thick Mo foil were measured at beam energies of 1.84 MeV/u, 2.09 MeV/u, and 2.11 MeV/u respectively. A 1-D position sensitive Parallel Grid Avalanche Counter detector (PGAC) was used at the exit of a spectrograph magnet, enabling us to measure the intensity of several charge states simultaneously. The number of charge states measured for each beam constituted more than 99% of the total equilibrium charge state distribution for that elements. Currently, little experimental data exists for equilibrium charge state distributions for heavy ions with 19
The Mélange of Innovation and Tradition in Maltese Law: The Essence of the Maltese Mix?
B Andò
Potchefstroom Electronic Law Journal/Potchefstroomse Elektroniese Regsblad , 2012,
Abstract: Aim of this paper is to provide valuable insights into the Maltese legal system with a special focus on private law. The assumption is that this legal system is the byproduct of the "mixing" of innovation and tradition, resulting from the interaction of English law and continental law. A major role in the development of the system is played by courts. Some examples (moral damages and pre-contractual liability) are considered which highlight the importance of the function displayed by Maltese judges. KEYWORDS: Tradition; English law; continental law; hybridity; mixed legal systems; Maltese courts; moral damages; pre-contractual liability; lacunae
PROBLEMS OF FLIGHT PERSONNEL PREPARATION FOR MODERN AIRCRAFTS П ДГОТОВКА ЛЬОТНОГО СКЛАДУ НА СУЧАСН ПОВ ТРЯН СУДНА П ДГОТОВКА ЛЬОТНОГО СКЛАДУ НА СУЧАСН ПОВ ТРЯН СУДНА
B. Харченко,О. Ал?кс??в,Д. Бабейчук,М. Повознюк
Proceedings of National Aviation University , 2011,
Abstract: At present, the problem who can and who should solve the question concerning the preparationand recurrent training of pilots of Ukrainian civil aviation is not solved. The necessity of updatingof aircraft’s park in aviation branch and aircraft operation, which was ripened 10 years ago,demands a corresponding infrastructure. It is necessary to understand, that the pilots ready toperform the flights on modern aircrafts, will not appear by themselves, therefore the real actions onmodernization of existing system of aircrew and the aviation personnel preparation as a whole arerequired. Main objective of this work is the determination of the basic components concerning thesolving of the problematic questions on preparation of aircrew on modern types of aircrafts. Duringthe problem analysis it was specified that the present development of system of aircrew preparationin Ukraine is not perfect, and does not correspond the ICAO and EU requirements, therefore needsan immediate intervention at the highest State level. Trainings are not complex, as do not containthe elements of selection of aircrew members cooperation. Programs of recurrent training ofaircrew, courses of pilots training flight preparation were not reconsidered for many years Розглянуто проблему п дготовки п лот в цив льно ав ац Уккра ни, яка на сьогодн нев дпов да вимогам ICAO та С. Визначено основн складов п дготовки льотного складу насучасн пов трян судна.Ключов слова: аеронав гац йне обслуговування, керована множина, керован об’ кти,рад олокац йне та рад онав гац йне забезпечення польот в, системи керування пов трянимрухом. Розглянуто проблему п дготовки п лот в цив льно ав ац Уккра ни, яка на сьогодн нев дпов да вимогам ICAO та С. Визначено основн складов п дготовки льотного складу насучасн пов трян судна.
METHOD OF SYNTHESIS OF PROBLEM QUALITY OF THE COMPLEX NONLINEAR DYNAMIC SYSTEM CONTROL МЕТОД ГАРАНТОВАНОГО ОЦ НЮВАННЯ ОБЛАСТ ПОВН СТЮКЕРОВАНОГО СТАНУ СКЛАДНО НЕЛ Н ЙНО ДИНАМ ЧНО СИСТЕМИ МЕТОД ГАРАНТОВАНОГО ОЦ НЮВАННЯ ОБЛАСТ ПОВН СТЮ КЕРОВАНОГО СТАНУ СКЛАДНО НЕЛ Н ЙНО ДИНАМ ЧНО СИСТЕМИ
С. Павлова,B. Павлов,В. Чеп?женко
Proceedings of National Aviation University , 2011,
Abstract: Substantially nonlinear objects function at limitations of arbitrary kind. These limitations are not necessarily convex areas. For such objects the construction of area of the fully the fully-controlled state area is a serious problem. In the article it has been suggested to replace this task the task of the fully-controlled state area estimation from within. The secure estimation method of the fully-controlled state area has been developed for this purpose. Other dynamic system has been used as a tester (measure) of the fully-controlled state area. Construction and estimation of controllability and accessibility area of this dynamic system well methodically validate and deserved researchers confession. The descriptions concordance requirements of this new object with properties of initial object must be executed and provide property of immersion of new object in an initial object. Possibility is thus opened on the the fully-controlled state area of new object to define the the fully-controlled state area of the initial system На основ процедури мерсування м рних об’ кт в у вих дний об’ кт розроблено методгарантованого оц нювання област повн стю керованого стану.On the basis of procedure of immersion of the measuring objects in an initial object the secureestimation method of the fully controlled state area has been developed.На основе процедуры иммерсирования мерных объектов в исходный объект разработанметод гарантированного оценивания области полностью управляемого состояния. Показано, що для стотно нел н йних об’ кт в, що функц онують в умовах наявност обме-жень дов льного виду, як не обов’язково опуклими областями, побудова област повн стюкерованого стану проблематична. Запропоновано зам нити це завдання оц нюванням област повн стю керованого стану зсередини. Для цього розроблено метод гарантовано оц нюванняобласт повн стю керованого стану. Як вим рника (м ра) област повн стю керованого станувикористана нша динам чна система, п
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