arXiv subjects

Inaki Lara

Publications and source records attributed to Inaki Lara.

5 recordsLinked to original sources

arXiv2021

Explaining muon $g-2$ data in the $μν$SSM

We analyze the anomalous magnetic moment of the muon $g-2$ in the $μν$SSM. This $R$-parity violating model solves the $μ$ problem reproducing simultaneously neutrino data, only with the addition of right-handed neutrinos. In the framework of the $μν$SSM, light left muon-sneutrino and wino masses can be naturally obtained driven by neutrino physics. This produces an increase of the dominant chargino-sneutrino loop contribution to muon $g-2$, solving the gap between the theoretical computation and the experimental data. To analyze the parameter space, we sample the $μν$SSM using a likelihood data-driven method, paying special attention to reproduce the current experimental data on neutrino and Higgs physics, as well as flavor observables such as $B$ and $μ$ decays. We then apply the constraints from LHC searches for events with multi-leptons + MET on the viable regions found. They can probe these regions through chargino-chargino, chargino-neutralino and neutralino-neutralino pair production. We conclude that significant regions of the parameter space of the $μν$SSM can explain muon $g-2$ data.

hep-ph↗

arXiv2019

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

Within the framework of the $μν$SSM, 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 $μν$SSM for a tau left sneutrino LSP with proper decay length $cτ> 0.1$ mm 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 $μν$SSM 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.

hep-ph↗

arXiv2019

Electroweak superpartners scrutinized at the LHC in events with multi-leptons

We analyze a multi-lepton signal plus missing transverse energy from neutrinos expected at the LHC for a Bino-like neutralino as the lightest supersymmetric particle (LSP), when the left sneutrino is the next-to-LSP and hence a suitable source of Binos. The discussion is carried out in the framework of the $μν$SSM, where the presence of $R$-parity violating (RPV) couplings involving right-handed neutrinos solves the $μ$ problem and can reproduce simultaneously the neutrino data. Left sneutrinos/sleptons are pair produced at $pp$ collisions decaying to Binos, with the latter decaying via RPV to $W\ell$ or $Zν$. This signal can be compared with LHC searches for electroweak superpartners through chargino-neutralino production. The reduced cross section of the sneutrino/slepton production in comparison with the one of the latter process, limits the sensitivity of the searches to small sneutrino/slepton masses. Although the resulting compressed spectrum typically evades the aforementioned searches, we show that analyses using recursive jigsaw reconstruction are sensitive to these scenarios. As a by-product, we find that the region of Bino masses $110-120$ GeV and sneutrino masses $120-140$ GeV can give rise to a tri-lepton signal compatible with the local excess recently reported by ATLAS.

hep-ph↗

arXiv2018

Looking for the left sneutrino LSP with displaced-vertex searches

We analyze a displaced dilepton signal expected at the LHC for a tau left sneutrino as the lightest supersymmetric particle with a mass in the range $45$-$100$ GeV. The sneutrinos are pair produced via a virtual $W$, $Z$ or $γ$ in the $s$ channel and, given the large value of the tau Yukawa coupling, their decays into two dileptons or a dilepton plus missing transverse energy from neutrinos can be significant. The discussion is carried out in the $μν$SSM, where the presence of $R$-parity violating couplings involving right-handed neutrinos solves the $μ$ problem and can reproduce the neutrino data. To probe the tau left sneutrinos we compare the predictions of the $μν$SSM with the ATLAS search for long-lived particles using displaced lepton pairs in $pp$ collisions at $\sqrt s= 8$ TeV, allowing us to constrain the parameter space of the model. We also consider an optimization of the trigger requirements used in existing displaced-vertex searches by means of a High Level Trigger that exploits tracker information. This optimization is generically useful for a light metastable particle decaying into soft charged leptons. The constraints on the sneutrino turn out to be more stringent. We finally discuss the prospects for the $13$ TeV LHC searches as well as further potential optimizations.

hep-ph↗

arXiv2018

Searching for left sneutrino LSP at the LHC

We analyze relevant signals expected at the LHC for a left sneutrino as the lightest supersymmetric particle (LSP). The discussion is carried out in the `$μ$ from $ν$' supersymmetric standard model ($μν$SSM), where the presence of $R$-parity breaking couplings involving right-handed neutrinos solves the $μ$ problem and reproduces neutrino data. The sneutrinos are pair produced via a virtual $W$, $Z$ or $γ$ in the $s$ channel. From the prompt decay of a pair of left sneutrinos LSPs of any family, a significant diphoton signal plus missing transverse energy (MET) from neutrinos can be present in the mass range 118-132 GeV, with 13 TeV center-of-mass energy and an integrated luminosity of 100 fb$^{-1}$. In addition, in the case of a pair of tau left sneutrinos LSPs, given the large value of the tau Yukawa coupling diphoton plus leptons and/or multileptons can appear. We find that the number of expected events for the multilepton signal, together with properly adopted search strategies, is sufficient to give a significant evidence for a sneutrino of mass in the range 130-310 GeV, even with the integrated luminosity of 20 fb$^{-1}$. In the case of the signal producing diphoton plus leptons, an integrated luminosity of 100 fb$^{-1}$ is needed to give a significant evidence in the mass range 95-145 GeV. Finally, we discuss briefly the presence of displaced vertices and the associated range of masses.

hep-ph↗