107 research outputs found

    Simplified models for same-spin new physics scenarios

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    Simplified models are an important tool for the interpretation of searches for new physics at the LHC. They are defined by a small number of new particles together with a specific production and decay pattern. The simplified models adopted in the experimental analyses thus far have been derived from supersymmetric theories, and they have been used to set limits on supersymmetric particle masses. We investigate the applicability of such simplified supersymmetric models to a wider class of new physics scenarios, in particular those with same-spin Standard Model partners. We focus on the pair production of quark partners and analyze searches for jets and missing energy within a simplified supersymmetric model with scalar quarks and a simplified model with spin-1/2 quark partners. Despite sizable differences in the detection efficiencies due to the spin of the new particles, the limits on particle masses are found to be rather similar. We conclude that the supersymmetric simplified models employed in current experimental analyses also provide a reliable tool to constrain same-spin BSM scenarios.Comment: 11 pages + references, 7 figures; v2: added references, minor improvements in the presentatio

    Constraints on models with universal extra dimensions from dilepton searches at the LHC

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    Models with universal extra dimensions predict that each Standard Model particle is accompanied by a tower of Kaluza-Klein resonances. Canonical searches for the production and cascade decays of first Kaluza-Klein modes through missing transverse momentum signatures suffer in general from low detection efficiencies because of the rather compressed Kaluza-Klein particle mass spectrum. Here, instead we analyze signatures from the production of second Kaluza-Klein states which can decay into Standard Model particles and thus do not result in any missing transverse momentum. Such signatures provide a strong sensitivity, and are of particular interest as they would allow for a clear distinction between extra dimension models and other models of new physics like supersymmetry. We constrain the production of second Kaluza-Klein particles from recent LHC searches for dilepton resonances, and place limits on the compactification scale to be larger than 715GeV, and on the masses of the second Kaluza-Klein particles to be larger than 1.4TeV.Comment: 11 pages, 4 figures, analysis updated (inclusion of data from CMS-PAS-EXO-12-061), MUED bound improved to R^{-1} > 715 GeV, version published in JHE

    Constraining supersymmetry at the LHC with simplified models for squark production

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    An important tool for interpreting LHC searches for new physics are simplified models. They are characterized by a small number of parameters and thus often rely on a simplified description of particle production and decay dynamics. Considering the production of squarks of the first two generations we compare the interpretation of current LHC searches for hadronic jets plus missing energy signatures within simplified models with the interpretation within a complete supersymmetric model. Although we find sizable differences in the signal efficiencies, in particular for large supersymmetric particle masses, the differences between the mass limits derived from a simplified model and from the complete supersymmetric model are moderate given the current LHC sensitivity. We conclude that simplified models provide a reliable tool to interpret the current hadronic jets plus missing energy searches at the LHC in a more model-independent way.Comment: 11 pages + references, 5 figures; v2: title changed, minor improvements in the presentatio

    Use of Homeopathy in Pediatric Oncology in Germany

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    Homeopathy is a frequently used complementary and alternative medicine (CAM) treatment. We present results comparing responses of homeopathy users (HUs) and users of other forms of CAM (NHUs) in pediatric oncology (PO) in Germany. Differences between these two groups (usage, associated demographic characteristics, previous experience with CAM) are investigated. 186 (45.2%) of the 367 CAM users were exposed to homeopathy. The treatment duration amounted to a median of 601 days for HUs and 282 days for NHUs. Parents with p (127; 76.5%) also used homeopathy for their child's cancer. Nonmedical practitioners played a considerably greater role as source of information than did treating physician. In the majority HUs received their prescriptions from nonmedical practitioners (56%; 29.4% of NHUs). HUs communicate more frequently with their physicians about the CAM-use (77.7% versus 65.2%) and recommend CAM more often than NHUs (94% versus 85.6%). Homeopathy is the most frequently used CAM treatment in PO in Germany. HUs sustain treatment and therapies considerably longer than NHUs. Most families who had used homeopathy before their child was diagnosed with cancer also used homeopathy for the treatment of their child's cancer. Compared to other CAM treatments, patient satisfaction with homeopathy appears to be very high
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