113 research outputs found
A singular way to search for heavy resonances in missing energy events
No full text© 2020, The Author(s). The phase space of visible particles in missing energy events may have singularity structures. The singularity variables are devised to capture the singularities effectively for given event topology. They can greatly improve the discovery potential of new physics signals as well as to extract the mass spectrum information at hadron colliders. Focusing on the antler decay topology of resonance, we derive a novel singularity variable whose distribution has endpoints directly correlated with the resonance mass. As a practical application, we examine the applicability of the singularity variable to the searches for heavy neutral Higgs bosons in the two-Higgs doublet model11Nsciescopu
Interventions for Neglect With Stroke: A Systematic Review
No full textAbstract
Date Presented 3/31/2017
Using the key terms stroke, neglect, and intervention, we systematically examined 14 studies included in our analysis. This review will provide direction and an evidence base for occupational therapy in hospital settings.
Primary Author and Speaker: Seok Beom Ko
Additional Authors and Speakers: Ju Hee Kim, Moon Young Kim, Hae Yean Park</jats:p
Could MT2 be a singularity variable?
No full text© 2021, The Author(s).The algebraic singularity method is a framework for analyzing collider events with missing energy. It provides a way to draw out a set of singularity variables that can catch singular features originating from the projection of full phase space onto the observable phase space of measured particle momenta. It is a promising approach applicable to various physics processes with missing energy but still requires more studies for use in practice. Meanwhile, in the double-sided decay topology with an invisible particle on each side, the MT2 variable has been known to be a useful collider observable for measuring particle masses from missing energy events or setting signal regions of collider searches. We investigate the relation between the two different types of kinematic variables in double-sided decay topology. We find that the singularity variables contain the MT2 variable in many cases, although the former is not a strict superset of the latter.11Nsciescopu
Correction: Corrigendum: Functional solid additive modified PEDOT:PSS as an anode buffer layer for enhanced photovoltaic performance and stability in polymer solar cells
No full textScientific Reports 7: Article number: 45079; published online: 24 March 2017; updated: 04 May 2017 The original version of this Article contained a typographical error in the spelling of the author Jin-Beom Kwon, which was incorrectly given as Jin-Beon Kwon. This has now been corrected in both the PDF and HTML versions of the Article.</jats:p
Mixed modulus and anomaly mediation in light of the muon g − 2 anomaly
No full text© 2021, The Author(s).The new measurement of the anomalous magnetic moment of muon at the Fermilab Muon g− 2 experiment has strengthened the significance of the discrepancy between the standard model prediction and the experimental observation from the BNL measurement. If new physics responsible for the muon g− 2 anomaly is supersymmetric, one should consider how to obtain light electroweakinos and sleptons in a systematic way. The gauge coupling unification allows a robust prediction of the gaugino masses, indicating that the electroweakinos can be much lighter than the gluino if anomaly-mediated supersymmetry breaking is sizable. As naturally leading to mixed modulus-anomaly mediation, the KKLT scenario is of particular interest and is found capable of explaining the muon g− 2 anomaly in the parameter region where the lightest ordinary supersymmetric particle is a bino-like neutralino or slepton.11Nsciescopu
New approach to semileptonic tags in B -meson semi-invisible decays
No full textSemi-invisible decays of mesons are a prime strategy for searches of new particles or forbidden decays. At current and upcoming facilities beauty mesons are produced in pairs, and the second decay often provides a tagto enhance signal reconstruction. Typical tags are fully reconstructed, hadronic decays, whereas one tends to discard semileptonicmodes, clean and abundant, but with an elusive neutrino. We introduce a new strategy that makes semileptonic tags competitive with hadronic tags, potentially implying a substantial increase in the usable event statistics for any semi-invisible meson or τ-lepton decay. Our strategy rests on the use of appropriate kinematic quantities, collectively denoted as M2, that had never been applied in the context of meson decays. We introduce M2 definitions that leverage two key features of high-intensity meson-decay events: the known decaying-meson mass and its flight direction - accessible thanks to the exquisite vertexing capabilities available. We benchmark these definitions in the B→Kτμ, a null test of the Standard Model of great current interest. In an unrefined application we already observe a substantial improvement in sensitivity - halfway to the ideal case of using fully reconstructed semileptonic tags with true kinematics. © 2023 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the https://creativecommons.org/licenses/by/4.0/Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.11Nsciescopu
Determination of the band parameters of bulk 2H-MX2 (M = Mo, W; X = S, Se) by angle-resolved photoemission spectroscopy
No full textMonolayer MX2 (M = Mo, W; X = S, Se) has recently been drawn much attention due to their application possibility as well as the novel valley physics. On the other hand, it is also important to understand the electronic structures of bulk MX2 for material applications since it is very challenging to grow large size uniform and sustainable monolayer MX2. We performed angle-resolved photoemission spectroscopy and tight binding calculations to investigate the electronic structures of bulk 2H-MX2. We could extract all the important electronic band parameters for bulk 2H-MX2, including the band gap, direct band gap size at K (-K) point and spin splitting size. Upon comparing the parameters for bulk 2H-MX2 (our work) with mono- and multi-layer MX2 (published), we found that stacked layers, substrates for thin films, and carrier concentration significantly affect the parameters, especially the band gap size. The origin of such effect is discussed in terms of the screening effect. © The Author(s) 20161341sciescopu
Calibration of traffic simulation models using Simultaneous Perturbation Stochastic Approximation (SPSA) method extended through Bayesian sampling methodology
No full textThe main goal of this dissertation is to propose a new methodology for the calibration of traffic simulation models. Simulation is useful in representing complex real-world systems, and many alternatives can be compared via different system designs. However, to evaluate road conditions accurately, the selection of model parameters to be calibrated and the calibration methodology are very important aspects of the overall simulation modeling process.
One of the key elements of this dissertation is the application of the Simultaneous Perturbation Stochastic Approximation (SPSA) algorithm (Spall (1992))--one of the well-known stochastic approximation (SA) algorithms, to determine optimal model parameters. The SPSA algorithm has an inherent advantage that can be exploited in both stochastic gradient and gradient-free settings; it can also be applied to solve optimization problems that have a large number of variables.
One of the main distinctions between this study and previous studies is with regards to calibration while considering a wide range of all likely demand conditions. Previous studies on calibration have focused on minimizing a deterministic objective function, which is the sum of the relative error between the observed data and the simulation output from a certain time period in a typical day. Even though this approach can be considered a calibration that uses data obtained at one point in time, this type of calibration approach cannot capture a realistic distribution of all possible traffic conditions. Thus, a more general calibration methodology needs to be implemented--one that enables use with any traffic condition. In this dissertation, we propose the Bayesian sampling approach, in conjunction with the application of the SPSA stochastic optimization method, which enables the modeler to enhance the theoretic application to consider statistical data distribution. Thus, this proposed new and advanced methodology makes it possible to overcome the limitations of previous calibration studies.
Testing the methodology for larger networks, as well as for other microscopic traffic simulation tools such as CORSIM or VISSIM, are future research tasks. In the future, other simulation parameters and more extensive data sets can be used to test the strengths and weaknesses of the proposed calibration methodology.Ph.D.Includes bibliographical references (p. 144-148)
Propeller-engine interaction in a dynamic model scale environment
No full textRegulatory demands on ship designs, such as emission and manoeuvrability requirements, are becoming increasingly stringent, raising the need for advanced methods to predict and assess dynamic propulsion plant behaviour of a new design. At present, model scale experiments and numerical simulations are not able to predict this behaviour in full detail. To fill the resulting knowledge gap, this paper proposes to further develop existing scale model tests into so-called dynamic model basin tests. These tests aim to predict dynamic behaviour of the ship propulsion plant in complex, dynamic environments in more detail, leading to improved propulsion systems and controls and ultimately, lower emissions, lower fuel consumption and increased manoeuvrability.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Ship Design, Production and Operation
Light Higgs bosons in the general NMSSM
No full textPhysics beyond the Standard Model (SM) may manifest itself as small deviations from the SM predictions for Higgs signal strengths at 125 GeV. Then, a plausible and interesting possibility is that the Higgs sector is extended and at the weak scale there appears an additional Higgs boson weakly coupled to the SM sector. Combined with the LEP excess in e+e--> Z(h -> bb over bar) rightarrow Z(h) the diphoton excess around 96 GeV recently reported by CMS may suggest such a possibility. We examine if those LEP and CMS excesses can be explained simultaneously by a singlet-like Higgs boson in the general next-to-minimal supersymmetric Standard Model (NMSSM). Higgs mixing in the NMSSM relies on the singlet coupling to the MSSM Higgs doublets and the higgsino mass parameter, and thus is subject to the constraints on these supersymmetric parameters. We find that the NMSSM can account for both the LEP and CMS excesses at 96 GeV while accommodating the observed 125 GeV SM-like Higgs boson. Interestingly, the required mixing angles constrain the heavy doublet Higgs boson to be heavier than about 500 GeV. We also show that the viable region of mixing parameter space is considerably modified if the higgsino mass parameter is around the weak scale, mainly because of the Higgs coupling to photons induced by the charged higgsinos. © The Author(s) 201911Nsciescopu
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