جسيمات خفية: مطاردة الجسيمات طويلة العمر في أطلس سريع

الملخص الأصلي

كما كتبه المؤلفون، بالإنجليزية arXiv:2601.05664

A search is presented for long-lived particles decaying into an oppositely charged lepton pair, $$\mu^{+}\mu^{-}$$, $$e^{+}e^{-}$$, or $$e^{\pm}\mu^{\mp}$$, that form a vertex within the inner tracking system of the ATLAS detector at the Large Hadron Collider, displaced from the primary proton-proton interaction region. The analysis uses the 140 fb$$^{-1}$$ of Run-2 data collected at $$\sqrt{s}=13$$ TeV by the ATLAS experiment in 2015-2018. The results of the analysis are interpreted in the context of three benchmark models covering masses from 0.1 to 2.2 TeV and a range of mean proper lifetimes times the speed of light from 1 to 10000 mm. The first model is a generic $$Z'$$ boson pair-produced by a new heavy scalar, with the $$Z'$$ decaying into lepton pairs. The remaining two models are $$R$$-parity violating supersymmetric models in which the lightest neutralino $$\tilde{\chi}^{0}_{1}$$ decays into $$\ell^{+}\ell^{'-} u$$ ($$\ell, \ell^{'} = e$$, $$\mu$$). The models differ by the mode of production of the $$\tilde{\chi}^{0}_{1}$$, which can be produced via the decay of pairs of gluinos or of pairs of charginos and neutralinos ($$\tilde{\chi}_{1}^{\pm}\tilde{\chi}_{1}^{0}$$, $$\tilde{\chi}_{1}^{\pm}\tilde{\chi}_{2}^{0}$$, or $$\tilde{\chi}_{2}^{0}\tilde{\chi}_{1}^{0}$$). Although each benchmark sample includes pair-produced LLPs, only a single vertex is required to be reconstructed. No dilepton displaced vertex candidate is observed and the results are presented as upper limits on the production cross-sections. This analysis sets leading limits on the production cross-sections for multiple models, including parameter space that has never been directly probed.