Probing the electroweak sector of the μνSSM at the LHC

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física Teórica. Fecha de lectura: 22-01-201

LHC constraints on electroweakino dark matter revisited

We revisit LHC searches for heavy invisible particles by exploiting QCD initial state radiation. We recast a dijet signal region in a general multijet plus MET search by ATLAS. We find that non-trivial mass limit can be obtained for various models of the electroweakino sector with the present data in hadronic channels. The winos are bound to be heavier than $m_{\tilde W} \gtrsim {160}$ GeV and higgsinos $m_{\tilde h} \gtrsim {100}$ GeV, depending on the chargino-neutralino mass splitting. The expected exclusion limits at the LHC Run 3 with $\mathcal{L} = 300$ fb$^{-1}$ increase to $m_{\tilde W} \gtrsim {200}$ GeV and $m_{\tilde h} \gtrsim {130}$ GeV for winos and higgsino, respectively. This is the first LHC limit for promptly decaying nearly mass-degenerate winos.Comment: 8 pages, 5 figures; updated references, expectations for LHC Run 3 added; to appear in PR

Searching for sbottom LSP at the LHC

Assuming that the sbottom is the lightest supersymmetric particle (LSP), we carry out an analysis of the relevant signals expected at the LHC. The discussion is established in the framework of the $\mu\nu$SSM, where the presence of $R$-parity violating couplings involving right-handed neutrinos solves simultaneously the $\mu$-problem and the accommodation of neutrino masses and mixing angles. The sbottoms are pair produced at the LHC, decaying to a lepton and a top quark or a neutrino and a bottom quark. The decays can be prompt or displaced, depending on the regions of the parameter space of the model. We focus the analysis on the right sbottom LSP, since the left sbottom is typically heavier than the left stop because of the D-term contribution. We compare the predictions of this scenario with ATLAS and CMS searches for prompt and long-lived particles. To analyze the parameter space we sample the $\mu\nu$SSM for a right sbottom LSP, paying special attention to reproduce the current experimental data on neutrino and Higgs physics, as well as flavor observables. For displaced (prompt) decays, our results translate into lower limits on the mass of the right sbottom LSP of about $1041$ GeV ($1070$ GeV). The largest possible value found for the decay length is about $3.5$ mm.Comment: 26 pages, 4 figures, 3 tables, 1 appendix. Analysis of the stop LSP at the LHC carried out in arXiv:2111.1321

Monojet signatures from gluino and squark decays

In this paper, we study the monojet and dijet channels at the LHC as a tool for searching for squarks and gluinos. We consider two separate scenarios. In the first scenario we postulate a large mass hierarchy between the squarks ($\tilde q$) and the wino ($\widetilde W$), which is assumed to be the lightest supersymmetric particle (LSP). The associated squark-wino production, $pp \to \tilde q \widetilde W$, then leads to a monojet-like signature, where the high $p_T$ jet originates from the squark decay, $\tilde q \to q + \widetilde W$. We demonstrate that this associated production, as well as the $pp \to \widetilde W \widetilde W + {\rm jets}$ production, have a significant impact on the exclusion limit in the squark-neutralino mass plane. The second scenario postulates that the lighter of the squark and gluino is almost mass degenerate with the lightest neutralino. The associated squark-gluino production, $pp \to \tilde q \tilde g$, then leads to a distinctive monojet signature, where the high $p_T$ jet is produced from the decay of the heavier coloured particle into the lighter one ($\tilde q \to q + \tilde g$ for $m_{\tilde q} > m_{\tilde g}$ and $\tilde g \to q + \tilde q$ for $m_{\tilde g} > m_{\tilde q}$). The lighter coloured particle is effectively regarded as an invisible particle since the decay products are soft due to the approximate mass degeneracy. We recast existing monojet-type analyses and find a non-trivial exclusion limit in the squark-gluino mass plane in this scenario.Comment: 19 pages, 10 figure

The new (g−2)μ(g-2)_\mu result and the μν\mu\nuSSM

The $\mu\nu$SSM is a highly predictive alternative model to the MSSM. In particular, the electroweak sector of the model can explain the longstanding discrepancy between the experimental result for the anomalous magnetic moment of the muon, $(g-2)_\mu$, and its Standard Model prediction, while being in agreement with all other theoretical and experimental constraints. The recently published MUON G-2 result is within $0.8\,\sigma$ in agreement with the older BNL result on $(g-2)_\mu$. The combined result was announced as $a_\mu^{\rm exp} = (11659206.1 \pm 4.1) \times 10^{-10}$, yielding a new deviation from the Standard Model prediction of $\Delta a_\mu = (25.1 \pm 5.9) \times 10^{-10}$, corresponding to $4.2\,\sigma$. Using this improved bound we update the analysis in the $\mu\nu$SSM as presented in Ref. [1] and set new limits on the allowed parameters space of the electroweak sector of the model. We conclude that significant regions of the model can explain {the new} $(g-2)_\mu$ data.Comment: 30 pages, 9 figures, 1 table. Follow-up of arXiv:1912.0416

CFD simulation of a novel anaerobic-anoxic reactor for biological nutrient removal: model construction, validation and hydrodynamic analysis based on OpenFOAM®

AnoxAn is a novel multi-environment reactor for biological nutrient removal (BNR) from wastewater. Although its biological efficacy has been demonstrated on a pilot scale, hydrodynamics is observed to significantly affect the performance of AnoxAn. To study its complex hydraulic behaviour, a model based on Computational Fluid Dynamics 3D (CFD) is constructed using the OpenFOAM® open source toolbox and validated by experimental tests of Residence Time Distribution (RTD). Reactor elements represent a key factor in the modelling process. In this sense, the impeller of the anoxic zone is modelled as a flat disk, and the baffle after the anoxic zone as a porous media. According to CFD model simulations, stagnant, short-circuit zones and mixing quality are established and quantified. Finally, the influence on the hydrodynamics of reactor elements is also evaluated. The results of this detailed hydrodynamic analysis will form the basis for the design and optimization of scalable AnoxAn configurations.Peer ReviewedPostprint (author's final draft

Sampling the μν SSM for displaced decays of the tau left sneutrino LSP at the LHC

Within the framework of the μνSSM , a displaced dilepton signal is expected at the LHC from the decay of a tau left sneutrino as the lightest supersymmetric particle (LSP) with a mass in the range 45–100 GeV. We compare the predictions of this scenario with the ATLAS search for long-lived particles using displaced lepton pairs in pp collisions, considering an optimization of the trigger requirements by means of a high level trigger that exploits tracker information. The analysis is carried out in the general case of three families of right-handed neutrino superfields, where all the neutrinos get contributions to their masses at tree level. To analyze the parameter space, we sample the μνSSM for a tau left sneutrino LSP with proper decay length cτ>0.1mm using a likelihood data-driven method, and paying special attention to reproduce the current experimental data on neutrino and Higgs physics, as well as flavor observables. The sneutrino is special in the μνSSM since its couplings have to be chosen so that the neutrino oscillation data are reproduced. We find that important regions of the parameter space can be probed at the LHC run 3.Fil: Kpatcha, Essodjolo. Universidad Autónoma de Madrid; EspañaFil: Lara, Iñaki. Universidad Autónoma de Madrid; España. Institute for Basic Science. Center for Theoretical Physics of the Universe; Corea del NorteFil: Lopez, Daniel Elbio. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Muñoz, Carlos. Universidad Autónoma de Madrid; EspañaFil: Nagata, Natsumi. University Of Tokyo; JapónFil: Otono, Hidetoshi. Kyushu University; JapónFil: de Austri, Roberto Ruiz. Instituto de Física Corpuscular; Españ

Validation of UVEDAI: An Index for Evaluating the Level of Inflammatory Activity in Uveitis

Introduction Uveitis is the inflammation of the middle layer of the eye, the uvea, and is a major cause of blindness. None of the instruments used in clinical practice are, in themselves, sufficient to evaluate the course of uveitis. Therefore, it is necessary to develop instruments enabling standardized measurement of inflammatory activity. We developed a composite disease activity index for patients with uveitis known as UVEDAI, which considers the overall activity of the eye. The objective of this study was to validate the composite index of ocular inflammation, UVEDAI. Methods A multicenter cross-sectional study involving eight Spanish tertiary hospitals. Sixty-two patients aged ≥ 18 years with acute uveitis were recruited. Participants gave informed consent before participating in the study. A full ophthalmological examination was performed by two ophthalmologists to determine inflammatory activity: one used the UVEDAI score and the other used clinical judgment. The ophthalmologists did not share their findings with each other to avoid introducing bias into the analysis. Construct validity was established by means of factor analysis. The criterion validity of the index was determined using an ordinal multivariate regression model, in which the dependent variable was the degree of uveal inflammation (mild, moderate, or high/severe). Cut-off points were determined for the UVEDAI and for the receiver operating characteristic (ROC) curves. Results Sixty-two patients were included. Total variance with the three components accounted for 80.32% of the construct validity. Each of the three components identified one type of eye involvement. The discriminatory capacity of UVEDAI was 0.867 (95% CI 0.778; 0.955 p < 0.001) for mild versus moderate–high and 0.946 (95% CI 0.879; 1.000 p < 0.001) for high versus mild–moderate. Conclusions The variables included in UVEDAI enable ocular inflammatory activity to be described with a high degree of accuracy. The index may be used to evaluate and classify this activity with considerable discriminatory power.We would like to acknowledge the support of Abbvie: this study was conducted with an unrestricted grant from Abbvie. The Spanish Society of Rheumatology is the sponser and funder of this study and the journal's Rapid Service Fee, and has participated in the study design; in the analysis, and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication. The corresponding author had full access to all study data and had final responsibility for the decision to submit the manuscript for publication