1,985 research outputs found

    Indirect search for New Physics: complementarity to direct searches

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    We present an overview on the interplay between direct searches for new physics at the LHC and indirect constraints from the flavour sector, with an emphasis on the implications of the recent LHCb results. The complementarity with the Higgs search results will also be addressed. We show the correlation and complementarity between the different sectors in the context of a few specific examples in supersymmetry.Comment: 10 pages, 7 figures. Plenary talk at the 25th Rencontres de Blois on Particle Physics and Cosmology, Blois, France, 26-31 May 201

    SUSY and a 125 GeV Scalar

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    An excess of events at a mass of ~ 125 GeV has been reported by both ATLAS and CMS collaborations using 5/fb of data. If this excess of events is confirmed by further searches with more data, it will have extremely important consequences in the context of supersymmetric extensions of the Standard Model. We show that for a Standard Model like Higgs boson with a mass 122.5 < Mh < 127.5 GeV, several unconstrained or constrained MSSM scenarios would be excluded, while the parameters of some other scenarios would be severely restricted.Comment: 6 pages, 6 figures. Contribution to Moriond EW 2012 proceeding

    Flavour data constraints on new physics and SuperIso

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    We discuss the implications of B_s -> mu+mu- and B -> K*mu+mu- decays in the context of indirect searches for new physics, emphasising the new LHCb results. In particular, we derive the consequences of the MFV hypothesis and discuss the importance of the MFV predictions. The impact of the recent LHCb measurements in the context of the MSSM will also be addressed, and the SuperIso program will be briefly described.Comment: 7 pages, 4 figures, contribution to the ICHEP 2012 Conference proceedings, 4-11 July 2012, Melbourne, Australi

    Relic density and future colliders: inverse problem(s)

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    Relic density calculations are often used to constrain particle physics models, and in particular supersymmetry. We will show that the presence of additional energy or entropy before the Big-Bang nucleosynthesis can however completely change the relic density constraints on the SUSY parameter space. Therefore one should be extremely careful when using the relic density to constrain supersymmetry as it could give misleading results, especially if combined with the future collider data. Alternatively, we will also show that combining the discoveries of the future colliders with relic density calculations can shed light on the inaccessible pre-BBN dark time physics. Finally we will present SuperIso Relic, a new relic density calculator code in Supersymmetry, which incorporates alternative cosmological models, and is publicly available.Comment: 8 pages, 5 figures, contribution to the proceedings of the conference "Invisible Universe", Paris, June 29 - July 3, 2009, Franc

    On the LHCb anomaly in B -> K* l+ l-

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    The latest LHCb angular analysis of the rare decay B -> K* mu+ mu- shows some discrepancies from the SM up to the 3.7 sigma level. There is a consistent new physics explanation of these anomalies, while it is also reasonable that these anomalies are just statistical fluctuations and/or a direct consequence of underestimated hadronic uncertainties. We briefly discuss possible cross-checks of the various hypotheses with an analysis of the inclusive B -> Xs l+ l- based on the data collected by the B factories Babar and Belle and also based on future opportunities at SuperBelle. We also present a global analysis of the latest LHCb data under the hypothesis of Minimal Flavour Violation. The latter is an important benchmark scenario for new physics models. Any measurements beyond the MFV bounds and relations unambiguously indicate the existence of new flavour structures next to the Yukawa couplings of the Standard Model. However, if new physics is responsible for these discrepancies, we show it is compatible with the MFV hypothesis, so no new flavour structures are needed. Moreover, we analyse the impact of the correlations between the observables based on a Monte Carlo study.Comment: 23 pages, 9 figure

    LHC and ILC Data and the Early Universe Properties

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    With the start-up of the LHC, we can hope to find evidences for new physics beyond the Standard Model, and particle candidates for dark matter. Determining the parameters of the full underlying theory will be a long process requiring the combination of LHC and ILC data, flavor physics constraints, and cosmological observations. However, the Very Early Universe properties, from which the relic particles originate, are poorly known, and the relic density calculation can be easily falsified by hidden processes. We consider supersymmetry and show that determining the underlying particle physics parameters will help understanding the Very Early Universe properties.Comment: 6 pages, 2 figures, contribution to the proceedings of the workshop "LC09: e+e- Physics at the TeV Scale and the Dark Matter Connection", Perugia, September 21 - 24, 2009, Italy. v2: reference adde

    Production and decay of gluino pairs at hadron colliders

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    At hadron colliders, one of the most important channels for sparticle production is expected to be the gluino pair production. In the scenario where the sbottom is lighter than the gluino, gluinos can decay into sbottom and bottom quarks. Sbottoms can subsequently decay into bottom quarks and neutralinos. Hence, one expects a rich signature consisting of four b-jets and the missing transverse energy from neutralinos. To compute the cross section of this reaction, it is important to find tools and techniques suitable for the calculation of diagrams with many particles in the final state. We present here a way to deal with such complicated reactions.Comment: Proceedings of the Conference: "QCD and High Energy Hadronic Interactions", XXXXth Rencontres de Moriond, La Thuile, Italy - March 12-19, 2005 - 4 pages. References update

    Complementarity of direct and indirect searches in the pMSSM

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    We explore the pMSSM parameter space in view of the constraints from SUSY and monojet searches at the LHC, from Higgs data and flavour physics observables, as well as from dark matter searches. We show that whilst the simplest SUSY scenarios are already ruled out, there are still many possibilities left over in the pMSSM. We discuss the complementarity between different searches and consistency checks which are essential in probing the pMSSM and will be even more important in the near future with the next round of data becoming available.Comment: 6 pages, 9 figures. Contribution to the proceedings of the Fifth Capri Workshop on the interplay of flavour physics with electroweak symmetry breaking and dark matter, Capri, May 201

    Signs for new physics in the recent LHCb data?

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    We comment on some tensions with the Standard Model predictions in the recent LHCb data.Comment: 6 pages, 6 figures. Based on talks given at the Fifth Workshop on Theory, Phenomenology and Experiments in Flavour Physics, Capri, 23-25 May 2014 and at the FPCP 2014 conference on Flavor Physics and CP Violation, Marseille, 25-30 May 201

    Flavor constraints on two-Higgs-doublet models with general diagonal Yukawa couplings

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    We consider constraints from flavor physics on two-Higgs-doublet models (2HDM) with general, flavor-diagonal, Yukawa couplings. Analyzing the charged Higgs contribution to different observables, we find that b→sÎłb\to s\gamma transitions and ΔMBd\Delta M_{B_d} restrict the coupling λtt\lambda_{tt} of the top quark (corresponding to cot⁥ÎČ\cot\beta in models with a Z2Z_2 symmetry) to ∣λtt∣<1|\lambda_{tt}|<1 for mH+â‰Č500m_{H^+}\lesssim 500 GeV. Stringent constraints from BB meson decays are obtained also on the other third generation couplings λbb\lambda_{bb} and λττ\lambda_{\tau\tau}, but with stronger dependence on mH+m_{H^+}. For the second generation, we obtain constraints on combinations of λss\lambda_{ss}, λcc\lambda_{cc}, and λΌΌ\lambda_{\mu\mu} from leptonic KK and DsD_s decays. The limits on the general couplings are translated to the common 2HDM types I -- IV with a Z2Z_2 symmetry, and presented on the (mH+,tan⁥ÎČ)(m_{H^+},\tan\beta) plane. The flavor constraints are most excluding in the type II model which lacks a decoupling limit in tan⁥ÎČ\tan\beta. We obtain a lower limit mH+≳300m_{H^+}\gtrsim 300 GeV in models of type II and III, while no lower bound on mH+m_{H^+} is found for types I and IV.Comment: 24 pages, 11 figures. v2: Minor changes to text and numerics, results and conclusions unchanged. References adde
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