Search

Constraining Beyond the Standard Model theories usually involves scanning highly multi-dimensional parameter spaces and check observable predictions against experimental bounds and theoretical constraints. Such task is often timely and computationally expensive, especially when the model is severely constrained and thus leading to very low random sampling efficiency. In this work we tackled this challenge using Artificial Intelligence and Machine Learning search algorithms used for Black-Box optimisation problems. Using the cMSSM and the pMSSM parameter spaces, we consider both the Higgs mass and the Dark Matter Relic Density constraints to study their sampling efficiency and parameter space coverage. We find our methodology to produce orders of magnitude improvement of sampling efficiency whilst reasonably covering the parameter space., We thank José Santiago Pérez and Jorge Romão for the careful reading of the paper draft and for the useful discussions. This work is supported by FCT - Fundação para a Ciência e a Tecnologia, I.P. under project CERN/FIS-PAR/0024/2019. FAS is also supported by FCT under the research grant with reference UI/BD/153105/2022. The computational work was partially done using the resources made available by RNCA and INCD under project CPCA/A1/401197/2021, info:eu-repo/semantics/publishedVersion

We investigate a scenario inspired by natural supersymmetry, where neutrino data is explained within a low-scale seesaw scenario. For this the Minimal Supersymmetric Standard Model is extended by adding light right-handed neutrinos and their superpartners, the R-sneutrinos. Moreover, we consider the lightest neutralinos to be Higgsino-like. We first update a previous analysis and assess to which extent does existing LHC data constrain the allowed slepton masses. Here we find scenarios where sleptons with masses as low as 175 GeV are consistent with existing data. However, we also show that the upcoming run will either discover or rule out sleptons with masses of 300 GeV, even for these challenging scenarios. We then take a scenario which is on the borderline of observability of the upcoming LHC run assuming a luminosity of 300 fb$^{-1}$. We demonstrate that a prospective international $e^+ e^-$ linear collider with a center of mass energy of 1 TeV will be able to discover sleptons in scenarios which are difficult for the LHC. Moreover, we also show that a measurement of the spectrum will be possible within 1-3 percent accuracy., Comment: 34 pages, 10 figures; v2: accepted for publication

We study a supersymmetric version of the type-III seesaw mechanism considering two variants of the model: a minimal version for explaining neutrino data with only two copies of 24 superfields and a model with three generations of 24-plets. The latter predicts, in general, rates for mu -> e gamma inconsistent with experimental data. However, this bound can be evaded if certain special conditions within the neutrino sector are fulfilled. In the case of two 24-plets, lepton flavor violation constraints can be satisfied much more easily. After specifying the corresponding regions in the minimal supergravity parameter space, we show that under favorable conditions one can test the corresponding flavor structures in the leptonic sector at the LHC. For this we perform Monte Carlo studies for the signals, also taking into account the supersymmetry background. We find that it is only of minor importance for the scenarios studied here., We thank J. C. Romao for providing us with his SPHENO FRONTEND which facilitated the scans over the parameter space, and B. O'Leary for providing an updated version of the LHC-FASER package for the cross section calculations. W. P. and Ch. W. thank the IFIC for hospitality during extended stays. Their work has been supported in part by the DFG Project No. PO-1337/2-1 and the Helmholtz Alliance "Physics at the Terascale." W. P. has been supported by the Alexander von Humboldt Foundation. M. H. acknowledges support from the Spanish MICINN Grants No. FPA2011-22975 and No. MULTIDARK CSD2009-00064, the Generalitat Valenciana Grant No. Prometeo/2009/091, and the EU Network Grant No. UNILHC PITN-GA-2009-237920.

The lightest supersymmetric particle may decay with branching ratios that correlate with neutrino oscillation parameters. In this case the CERN Large Hadron Collider (LHC) has the potential to probe the atmospheric neutrino mixing angle with sensitivity competitive to its low-energy determination by underground experiments. Under realistic detection assumptions, we identify the necessary conditions for the experiments at CERN's LHC to probe the simplest scenario for neutrino masses induced by minimal supergravity with bilinear R parity violation., Work supported in part by Spanish grants FPA2008-00319/FPA, MULTIDARK Consolider CSD2009-00064 and PROMETEO/2009/091, by European network UNILHC, PITN-GA-2009-237920, by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), and by Fundaçao de Amparo à Pesquisa do Estado de Sao Paulo (FAPESP). F. de Campos thanks USP and IFIC/C.S.I.C. for hospitality. M.B.M. thanks IFIC/C.S.I.C. for hospitality. W.P. is supported by the DFG, Project No. PO-1337/1-1, and by the Alexander von Humboldt Foundation. D.R is partly supported by Sostenibilidad-UdeA/2009 grant.

9 pages, 4 figures.-- ISI article identifier:000264762400078.-- ArXiv pre-print avaible at: http://arxiv.org/abs/0902.0525, In models where the breaking of lepton number is spontaneous a massless Goldstone boson, the Majoron (J), appears. We calculate the theoretically allowed range for the branching ratios of Majoron-emitting charged lepton decays, such as Br(mu -> eJ) and Br(mu -> eJ gamma), in a supersymmetric model with spontaneous breaking of R-parity. Br(mu -> eJ) is maximal in the same region of parameter space for which the lightest neutralino decays mainly invisibly. A measurement of Br(mu -> eJ) thus potentially provides information on R-parity violation complementary to accelerator searches. We also briefly discuss existing bounds and prospects for future improvements on the Majoron coupling to charged leptons., This work was supported by Spanish grants FPA2008- 00319/FPA and Accion Integrada NO HA-2007-0090 (MEC). A.V. thanks the Generalitat Valenciana for financial support. W. P. is supported by the DAAD, Project No. D/07/13468, and partially by the German Ministry of Education and Research (BMBF) under contract 05HT6WWA.