67 research outputs found

    Beyond the Standard Model Searches at the LHC

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    This report presents recent results from studies of Beyond the Standard Model physics at the LHC. A focus is placed on heavy gauge bosons, electroweak symmetry breaking and left-right symmetry.Comment: Submitted to ICHEP06 proceeding

    Electroweak and Heavy Flavor Physics at SLD

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    We review recent electroweak and B physics results obtained in polarized e+e- interactions at the SLC by the SLD experiment. Unique and precise measurements of the electroweak parameters Ae, Ab, Ac, Rb and Rc provide powerful constraints on the Standard Model. The excellent 3-D vertexing capabilities of SLD are further exploited to extract precise B+ and B0 lifetimes, as well as measurements of the time evolution of B0-B0-bar mixing.Comment: 11 pages, 5 figures. Presented at the Workshop on Physics at the First Muon Collider and at the Front End of a Muon Collider, 6-9 November 1997, Fermilab, Batavia, I

    A Review of Bs Mixing: Past, Present and Future

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    We review the experimental status of Bs mixing. After a brief historical overview, current studies of the time dependence of Bs oscillations are described, with an emphasis on the different experimental techniques used by the ALEPH, CDF, DELPHI, OPAL, and SLD Collaborations. To conclude, the outlook for future experiments is presented.Comment: Paper submitted to proceedings of the 3rd International Conference on B Physics and CP Violation, Taipei, Dec.3-7, 1999; 8 pages, 4 figure

    Bη(η)K(π)B \to \eta(\eta') K(\pi) in the Standard Model with Flavor Symmetry

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    The observed branching ratios for BKηB\to K \eta' decays are much larger than factorization predictions in the Standard Model (SM). Many proposals have been made to reconcile the data and theoretical predictions. In this paper we study these decays within the SM using flavor U(3) symmetry. If small annihilation amplitudes are neglected, one needs 11 hadronic parameters to describe BPPB\to PP decays where PP can be one of the π\pi, KK, η\eta and η\eta' nonet mesons. We find that existing data are consistent with SM with flavor U(3) symmetry. We also predict several measurable branching ratios and CP asymmetries for BK(π)η(η)B \to K (\pi) \eta(\eta'), η(η)η(η)\eta(\eta')\eta(\eta') decays. Near future experiments can provide important tests for the Standard Model with flavor U(3) symmetry.Comment: 13 pages, 4 table

    Combined results on b-hadron production rates and decay properties

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    Combined results on b-hadron lifetimes, b-hadron production rates, B^0_d - \bar{B^0_d} and B^0_S - \bar{B^0_s} oscillations, the decay width difference between the mass eigenstates of the B^0_s - \bar{B^0_s} system, the average number of c and \bar{c} quarks in b-hadron decays, and searches for CP violation in the B^0_d - \bar{B-0_d} system are presented. They have been obtained from published and preliminary measurements available in Summer 2000 from the ALEPH, CDF, DELPHI, L3, OPAL and SLD Collaborations. These results have been used to determine the parameters of the CKM unitarity triangle

    Report from Working Group 3: Beyond the standard model physics at the HL-LHC and HE-LHC

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    This is the third out of five chapters of the final report [1] of the Workshop on Physics at HL-LHC, and perspectives on HE-LHC [2]. It is devoted to the study of the potential, in the search for Beyond the Standard Model (BSM) physics, of the High Luminosity (HL) phase of the LHC, defined as 33 ab1^{-1} of data taken at a centre-of-mass energy of 14 TeV, and of a possible future upgrade, the High Energy (HE) LHC, defined as 1515 ab1^{-1} of data at a centre-of-mass energy of 27 TeV. We consider a large variety of new physics models, both in a simplified model fashion and in a more model-dependent one. A long list of contributions from the theory and experimental (ATLAS, CMS, LHCb) communities have been collected and merged together to give a complete, wide, and consistent view of future prospects for BSM physics at the considered colliders. On top of the usual standard candles, such as supersymmetric simplified models and resonances, considered for the evaluation of future collider potentials, this report contains results on dark matter and dark sectors, long lived particles, leptoquarks, sterile neutrinos, axion-like particles, heavy scalars, vector-like quarks, and more. Particular attention is placed, especially in the study of the HL-LHC prospects, to the detector upgrades, the assessment of the future systematic uncertainties, and new experimental techniques. The general conclusion is that the HL-LHC, on top of allowing to extend the present LHC mass and coupling reach by 2050%20-50\% on most new physics scenarios, will also be able to constrain, and potentially discover, new physics that is presently unconstrained. Moreover, compared to the HL-LHC, the reach in most observables will, generally more than double at the HE-LHC, which may represent a good candidate future facility for a final test of TeV-scale new physics

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
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