456 research outputs found

    Inverse seesaw mechanism, leptogenesis, observable proton decay, and Δ<SUB>R</SUB><SUP>±±</SUP> in supersymmetric SO(10) with heavy W<SUB>R</SUB>

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    We explore the prospects of low-scale leptogenesis in a class of supersymmetric SO(10) models using extra singlet neutrinos (Ti, i=1, 2, 3) and the Higgs representations 126H&#8853; 126&#x0305;H as well as 16H&#8853;16&#x0305;H. A singlet neutrino, which we show can be as light as 105-106 GeV, decays through its small mixings with right-handed (RH) neutrinos creating a lepton asymmetry which is explicitly shown to be flavor dependent. While the doublet vacuum expectation value in 16&#x0305;H triggers the generation of desired mixings, it also induces a large RH-triplet vacuum expectation value that breaks the left-right intermediate gauge symmetry and gives large right-handed neutrino masses. Manifest unification of gauge couplings and generation of heavy RH neutrino masses are achieved by purely renormalizable interactions. The canonical (Type-I) seesaw contributions to the light neutrino mass matrix cancel out while the Type-II seesaw contribution is negligible. Determining the parameters of the dominant inverse seesaw formula by using the underlying quark-lepton symmetry and neutrino oscillation data, we show how leptogenesis under the gravitino constraint is successfully implemented. New formulas for the decay rate and the asymmetry parameter are derived leading to baryon asymmetry within the observed range without invoking a resonant condition on RH neutrinos. The model is found to work for hierarchical as well as inverted hierarchical light neutrino masses. Testable predictions of the model are RH doubly charged Higgs bosons which may be leptophilic and accessible to the Tevatron, LHC or a linear collider. In a model-independent manner, the Drell-Yan pair production cross section at the Tevatron or LHC is shown to be bounded between 59%-79% of their left-handed counterparts with same mass. In contrast to single-step breaking supersymmetric grand unified theories, which predict a long proton lifetime for the decay p&#8594;e+&#960;0, here this lifetime is substantially reduced, bringing it within one order of the current experimental limit

    Type II Seesaw Dominance in Non-supersymmetric and Split Susy SO(10) and Proton Life Time

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    Recently type II seesaw dominance in a supersymmetric SO(10) framework has been found useful in explaining large solar and atmospheric mixing angles as well as larger values of theta13theta_{13} while unifying quark and lepton masses. An important question in these models is whether there exists consistency between coupling unification and type II seesaw dominance. Scenarios where this consistency can be demonstrated have been given in a SUSY framework. In this paper we give examples where type II dominance occurs in SO(10) models without supersymmetry but with additional TeV scale particles and also in models with split-supersummetry. Grand unification is realized in a two-step process via breaking of SO(10) to SU(5) and then to a TeV scale standard model supplemented by extra fields and an SU(5) Higgs multiplet 15H{15}_H at a scale about 101210^{12} GeV to give type-II seesaw. The predictions for proton lifetime in these models are in the range τp0=2×1035\tau_p^0 = 2\times 10^{35} yrs. to τp0=6×1035\tau_p^0 = 6\times 10^{35} yrs.. A number of recent numerical fits to GUT-scale fermion masses can be accommodated within this model.Comment: 7 pages LaTeX, 3 figures, related areas: hep-ex, hep-th, astro-ph; Reference added, typo corrected, version to appear in Physical Review

    Neutrino mass and low-scale leptogenesis in a testable SUSY SO(10) model

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    It is shown that a supersymmetric SO(10) model extended with fermion singlets can accommodate the observed neutrino masses and mixings as well as generate the desired lepton asymmetry in concordance with the gravitino constraint. A necessary prediction of the model is near-TeV scale doubly-charged Higgs scalars which should be detectable at the LHC.Comment: Latex, 7 pages, 2 figures, minor clarifications added, to appear in Physics Letters

    Radiative Seesaw in SO(10) with Dark Matter

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    High energy accelerators may probe into dark matter and the seesaw neutrino mass scales if they are not much heavier than ~O(TeV). In the absence of supersymmetry, we extend a class of SO(10) models to predict well known cold dark matter candidates while achieving precision unification with experimentally testable proton lifetime. The most important prediction is a new radiative seesaw formula of Ma type accessible to accelerator tests while the essential small value of its quartic coupling also emerges naturally. This dominates over the high-scale seesaw contributions making a major impact on neutrino physics and dark matter, opening up high prospects as a theory of fermion masses.Comment: 11 pages LaTex, no figures.hep-ph, astro-ph, hep-th; Version accepted in Phys. Lett.

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

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    A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    Embracing open innovation to acquire external ideas and technologies and to transfer internal ideas and technologies outside

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    The objective of this dissertation is to increase understanding of how organizations can embrace open innovation in order to acquire external ideas and technologies from outside the organization, and to transfer internal ideas and technologies to outside the organization. The objective encompasses six sub-objectives, each addressed in one or more substudies. Altogether, the dissertation consists of nine substudies and a compendium summarizing the substudies. An extensive literature review was conducted on open innovation and crowdsourcing literature (substudies 1–4). In the subsequent empirical substudies, both qualitative research methods (substudies 5–7) and quantitative research methods (substudies 8–9) were applied. The four literature review substudies provided insights on the body of knowledge on open innovation and crowdsourcing. These substudies unveiled most of the influential articles, authors, and journals of open innovation and crowdsourcing disciplines. Moreover, they identified research gaps in the current literature. The empirical substudies offer several insightful findings. Substudy 5 shows how non-core ideas and technologies of a large firm can become valuable, especially for small firms. Intermediary platforms can find solutions to many pressing problems of large organizations by engaging renowned scientists from all over world (substudy 6). Intermediary platforms can also bring breakthrough innovations with novel mechanisms (substudy 7). Large firms are not only able to garner ideas by engaging their customers through crowdsourcing but they can also build long-lasting relations with their customers (substudies 8 and 9). Embracing open innovation brings challenges for firms too. Firms need to change their organizational structures in order to be able to fully benefit from open innovation. When crowdsourcing is successful, it produces a very large number of new ideas. This has the consequence that firms need to allocate a significant amount of resources in order to identify the most promising ideas. In an idea contest, customarily, only one or a few best ideas are rewarded (substudy 7). Sometimes, no reward is provided for the selected idea (substudies 8 and 9). Most of the ideas that are received are not implemented in practice
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