No Arabic abstract
One of the most striking signature of supersymmetric models with electroweak symmetry breaking is the presence of multilepton event topologies in the decay products. In this paper searches are presented for physics beyond the Standard Model (SM) in final states containing charged leptons from proton-antiproton collision data at a center-of-mass energy of 1.96 TeV, collected with Run II CDF and D{O}Detectors in 2002-2006, and corresponding to integrated luminosities of up to 1.1 fb$^{-1}$. In any of the searches no excess of candidates was observed with respect to the SM predictions and limits on masses and production cross-sections are set at the 95 % CL.
In this article results from supersymmetry searches at D0 and CDF are reported. Searches for third generation squarks, searches for gauginos, and searches for models with R-parity violation are described. As no signs of supersymmetry for these models are observed, the most stringent limits to date are presented.
We discuss some of the latest results from supersymmetry searches at the Tevatron
Motivated by the absence of any clear signal of physics beyond the Standard Model at the LHC after Run I, we discuss one possible slight hint of new physics and one non-minimal extension of the Standard Model. In the first part we provide a tentative explanation of a small excess of multilepton events, observed by the CMS collaboration, by means of a simplified model of gauge mediated supersymmetry breaking. In the second part we discuss how the standard phenomenology of gauge mediation can be significantly modified if one makes the non-minimal assumption that supersymmetry is broken in more than one hidden sector. Such multiple hidden sector models involve light neutral fermions called pseudo-goldstini and, due to the extra decay steps they induce, where soft photons are emitted, these models give rise to multiphoton plus missing energy signatures. We discuss why the existing LHC searches are poorly sensitive to these model and we propose new searches designed to probe them.
We study in detail the collider signatures of an $SU(2)_R$ fermionic quintuplet in the framework of left-right symmetric model in the context of the 13 TeV LHC. Apart from giving a viable dark matter candidate ($chi^0$), this model provides unique collider imprints in the form of same-sign multileptons through the decays of multi-charged components of the quintuplet. In particular, we consider the scenario where the quintuplet carries $(B - L) = 4$ charge, allowing for the presence of high charge-multiplicity particles with relatively larger mass differences among them compared to $(B - L)$ = 0 or 2. In this paper, we mainly focus on the same-sign n-lepton signatures (nSSL). We show that with an integrated luminosity of 500 $fb^{-1}$, the mass of the neutral component, $M_{chi^0} leq 480~(800)$ GeV can be excluded at 95% CL in the 2SSL (3SSL) channel after imposing several selection criteria. We also show that a $5sigma$ discovery is also achievable if $M_{chi^0} leq 390~(750)$ GeV in the 2SSL (3SSL) channel with 1000 $fb^{-1}$ integrated luminosity.
In this report, we summarize the latest results of the top-quark pair production asymmetry and present the new result of bottom-quark pair production asymmetry. By looking at the results obtained by the CDF experiment, one can see a discrepancy in both $tbar{t}$ inclusive and lepton-based measurements. The D0 results of the $tbar{t}$ production asymmetry are compatible with the standard-model predictions as well as with the CDF results. The CDF measurement of $bbar{b}$ production asymmetry presents consistency with both zero and with the standard-model predictions.