251 research outputs found

    SUSY-QCD corrections to stop annihilation into electroweak final states including Coulomb enhancement effects

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    We present the full O(αs)\mathcal{O}(\alpha_s) supersymmetric QCD corrections for stop-anti-stop annihilation into electroweak final states within the Minimal Supersymmetric Standard Model (MSSM). We also incorporate Coulomb corrections due to gluon exchange between the incoming stops. Numerical results for the annihilation cross sections and the predicted neutralino relic density are presented. We show that the impact of the radiative corrections on the cosmologically preferred region of the parameter space can become larger than the current experimental uncertainty, shifting the relic bands within the considered regions of the parameter space by up to a few tens of GeV.Comment: 20 pages, 13 figures, updated to version published in Phys. Rev.

    Precision predictions for supersymmetric dark matter

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    The dark matter relic density has been measured by Planck and its predecessors with an accuracy of about 2%. We present theoretical calculations with the numerical program DM@NLO in next-to-leading order SUSY QCD and beyond, which allow to reach this precision for gaugino and squark (co-)annihilations, and use them to scan the phenomenological MSSM for viable regions, applying also low-energy, electroweak and hadron collider constraints.Comment: 6 pages, 1 table, 8 figures, proceedings of ICHEP 201

    Constraining lepton number violating interactions in rare kaon decays

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    We investigate the possibility to probe lepton number violating (LNV) operators in the rare kaon decay K → πνν. Performing the analysis in the Standard Model effective field theory with only light active Majorana neutrinos, we determine the current limits on the corresponding LNV physics scale from the past E949 experiment at BNL as well as the currently operating experiments NA62 at CERN and KOTO at J-PARC. We focus on the specific signature of scalar currents in K → πνν arising from the LNV nature of the operators and study the effect on the experimental sensitivity, stressing the need for dedicated searches for beyond the SM currents. We find that the rare kaon decays probe high operator scales ΛLNV ≈ 15 to 20 TeV in different quark and neutrino flavours compared to neutrinoless double beta decay. Furthermore, we comment that the observation of LNV in kaon decays can put high-scale leptogenesis under tension. Finally, we discuss the connection with small radiatively generated neutrino masses and show how the severe constraints therefrom can be evaded in a minimal ultraviolet-complete scenario featuring leptoquarks

    Implications of rare kaon decays on lepton number violating interactions

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    We explore the possibility of lepton number violation (LNV) manifesting in the rare kaon decay K→πνν, its consequences for radiative neutrino mass generation and the washout of lepton asymmetry in high-scale leptogenesis scenarios. We perform the analysis in a model-independent framework, the Standard Model effective field theory (SMEFT). Possibilities to detect the LNV nature of the rare kaon decay are discussed in the context of the currently operating NA62 experiment at CERN and the KOTO experiment at J-PARC. We find that LNV could be detectable, and that any such detection would put high-scale leptogenesis under tension but could account for small radiatively generated neutrino masses

    Transition neutrino magnetic moments in CEνNS

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    Coherent Elastic Neutrino Nucleus Scattering (CEνNS) is a novel technique to look for new physics beyond the Standard Model. We study the prospects of probing a transition magnetic moment in CEνNS experiments. Showing the NUCLEUS experiment as an example, we demonstrate that properties of a potential sterile neutrino can be deduced

    Distinguishing Dirac vs Majorana Neutrinos at CEνNS experiments

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    A transition magnetic moment between active and sterile neutrinos can induce the Primakoff upscattering process at the coherent elastic neutrino nucleus scattering experiments, leading to very stringent limits on the transition dipole coupling as a function of the sterile neutrino mass. Here we discuss how a novel radiative upscattering mode with an additional photon emitted in the final state can lead to exploration of new parameter space in the transition dipole coupling vs. sterile neutrino mass plane and provide distinguishable differential distributions for a Dirac vs Majorana sterile state mediating such a mode

    A study of Docetaxel-induced effects in MCF-7 cells by means of Raman microspectroscopy

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    Chemotherapies feature a low success rate of about 25%, and therefore, the choice of the most effective cytostatic drug for the individual patient and monitoring the efficiency of an ongoing chemotherapy are important steps towards personalized therapy. Thereby, an objective method able to differentiate between treated and untreated cancer cells would be essential. In this study, we provide molecular insights into Docetaxel-induced effects in MCF-7 cells, as a model system for adenocarcinoma, by means of Raman microspectroscopy combined with powerful chemometric methods. The analysis of the Raman data is divided into two steps. In the first part, the morphology of cell organelles, e.g. the cell nucleus has been visualized by analysing the Raman spectra with k-means cluster analysis and artificial neural networks and compared to the histopathologic gold standard method hematoxylin and eosin staining. This comparison showed that Raman microscopy is capable of displaying the cell morphology; however, this is in contrast to hematoxylin and eosin staining label free and can therefore be applied potentially in vivo. Because Docetaxel is a drug acting within the cell nucleus, Raman spectra originating from the cell nucleus region were further investigated in a next step. Thereby we were able to differentiate treated from untreated MCF-7 cells and to quantify the cell–drug response by utilizing linear discriminant analysis models
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