761 research outputs found

    Higgs phenomenology in the Peccei-Quinn invariant NMSSM

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    We study the Higgs phenomenology in the Peccei-Quinn invariant NMSSM (PQ-NMSSM) where the low energy mass parameters of the singlet superfield are induced by a spontaneous breakdown of the Peccei-Quinn symmetry. In the generic NMSSM, scalar mixing among CP-even Higgs bosons is constrained by the observed properties of the SM-like Higgs boson, as well as by the LEP bound on the chargino mass and the perturbativity bound on the singlet Yukawa coupling. In the minimal PQ-NMSSM, scalar mixing is further constrained due to the presence of a light singlino-like neutralino. It is noticed that the 2Ļƒ2\sigma excess of the LEP ZbbĖ‰Zb\bar b events at mbbĖ‰ā‰ƒm_{b\bar b}\simeq 98 GeV can be explained by a singlet-like 98 GeV Higgs boson in the minimal PQ-NMSSM with low tanā”Ī²\tan\beta, stops around or below 1 TeV, and light doublet-higgsinos around the weak scale.Comment: 31 pages, 4 figures; v2: references added, light stop effects discussed, bound on the Higgs invisible decay rate correcte

    String theoretic QCD axions in the light of PLANCK and BICEP2

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    The QCD axion solving the strong CP problem may originate from antisymmetric tensor gauge fields in compactified string theory, with a decay constant around the GUT scale. Such possibility appears to be ruled out now by the detection of tensor modes by BICEP2 and the PLANCK constraints on isocurvature density perturbations. A more interesting and still viable possibility is that the string theoretic QCD axion is charged under an anomalous U(1)A gauge symmetry. In such case, the axion decay constant can be much lower than the GUT scale if moduli are stabilized near the point of vanishing Fayet-Illiopoulos term, and U(1)A-charged matter fields get a vacuum value v āˆ¼ (mSUSYMnPl)1/(n+1) (n ā‰„ 0) induced by a tachyonic SUSY breaking mass mSUSY. We examine the symmetry breaking pattern of such models during the inflationary epoch with HI ā‰ƒ 1014 GeV, and identify the range of the QCD axion decay constant, as well as the corresponding relic axion abundance, consistent with known cosmological constraints. In addition to the case that the PQ symmetry is restored during inflation, i.e. v(tI ) = 0, there are other viable scenarios, including that the PQ symmetry is broken during inflation with v(tI ) āˆ¼ (4HIMnPl)1/(n+1) āˆ¼ 1016ā€“1017 GeV due to the Hubble-induced D-term DA āˆ¼ 82H2 I , while v(t0) āˆ¼ (mSUSYMnPl)1/(n+1) āˆ¼ 109ā€“5Ɨ1013 GeV in the present universe, where v(t0) above 1012 GeV requires a fine-tuning of the axion misalignment angle. We also discuss the implications of our results for the size of SUSY breaking soft masses.131211Nsciescopu

    Atomistic Engineering of Phonons in Functional Oxide Heterostructures

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    Engineering of phonons, that is, collective lattice vibrations in crystals, is essential for manipulating physical properties of materials such as thermal transport, electron-phonon interaction, confinement of lattice vibration, and optical polarization. Most approaches to phonon-engineering have been largely limited to the high-quality heterostructures of IIIā€“V compound semiconductors. Yet, artificial engineering of phonons in a variety of materials with functional properties, such as complex oxides, will yield unprecedented applications of coherent tunable phonons in future quantum acoustic devices. In this study, artificial engineering of phonons in the atomic-scale SrRuO3/SrTiO3 superlattices is demonstrated, wherein tunable phonon modes are observed via confocal Raman spectroscopy. In particular, the coherent superlattices led to the backfolding of acoustic phonon dispersion, resulting in zone-folded acoustic phonons in the THz frequency domain. The frequencies can be largely tuned from 1 to 2 THz via atomic-scale precision thickness control. In addition, a polar optical phonon originating from the local inversion symmetry breaking in the artificial oxide superlattices is observed, exhibiting emergent functionality. The approach of atomic-scale heterostructuring of complex oxides will vastly expand material systems for quantum acoustic devices, especially with the viability of functionality integration

    Molecular docking and kinetic study of transglycosylation reaction for naringenin using amylosucrase from Deinococcus wulumuqiensis

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    The first Irish genome and ways of improving sequence accuracy

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    Whole-genome sequencing of an Irish person reveals hundreds of thousands of novel genomic variants. Imputation using previous known information improves the accuracy of low-read-depth sequencing

    Sub-sampled dictionaries for coarse-to-fine sparse representation-based human action recognition

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    Automatic human action recognition is a core functionality of systems for video surveillance and human-object interaction. However, the diverse nature of human actions and the noisy nature of most video content make it difficult to achieve effective human action recognition. To overcome the aforementioned problems, Sparse Representation (SR) has recently attracted substantial research attention. However, although SR-based approaches have proven to be reasonably effective, the computational complexity of the testing stage prohibits their usage by applications requiring support for real-time operation and a vast number of human action classes. In this paper, we propose a novel method for human action recognition, leveraging coarse-to-fine sparse representations that have been obtained through dictionary sub-sampling. Comparative experimental results obtained for the UCF50 dataset demonstrate that the proposed method is able to achieve efficient human action recognition, at no substantial loss in recognition accuracy

    Interā€Journal Knowledge Map using Citation Information and Subject Classification

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    In this paper, citation data that is crossā€referenced among journals is established using reference data in CrossRef. Using the established citation data, cited information is created and using DDC classification information, journals are classified. Using this interā€journal citation information, subject classification and time information, the relationship among the journals is analyzed. In other words, the relationship among frequently cited journals is expressed with DDC classification, and whether the subject classification is interā€related to journals and whether the subject journals are relevant are analyzed by year. As a result, it is shown that most journals are coā€related and that technology (600) in particular is strongly coā€related to natural science and mathematics (500) and social sciences (300). However, the analysis of journals by year shows that researches in the field of language (400) are conducted by heavily citing natural science and mathematics (500) but not the other way around with only a few citations after the year 2000. It is shown that there could be fusion among disciplines of no direct relations to each other
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