Related papers: Prospects for vectorlike leptons at future proton-…
Doubly charged excited leptons give rise to interesting signatures for physics beyond the standard model at the present Large Hadron Collider. These exotic states are introduced in extended isospin multiplets which couple to the ordinary…
The vector boson fusion (VBF) topology at the Large Hadron Collider at 14 TeV provides an opportunity to search for new physics. A feasibility study for the search of sleptons in a compressed mass spectra scenario is presented in the final…
The High-Luminosity Large Hadron Collider (HL-LHC) is expected to deliver an integrated luminosity of up to 3000 fb$^{-1}$. The very high instantaneous luminosity will lead to about 200 proton-proton collisions per bunch crossing (pileup)…
This Letter presents the first search for a heavy particle decaying into an e\mu final state in sqrt(s)=7 TeV pp collisions at the LHC. The data were recorded by the ATLAS detector during 2010 and correspond to a total integrated luminosity…
A search for strongly produced supersymmetric particles is conducted using signatures involving multiple energetic jets and either two isolated leptons ($e$ or $\mu$) with the same electric charge or at least three isolated leptons. The…
A search is presented for a new, light boson with a mass of about 1 GeV and decaying promptly to jets of collimated electrons and/or muons (lepton-jets). The analysis is performed with 20.3 fb$^{-1}$ of data collected by the ATLAS detector…
The discovery of the Higgs boson at the LHC exposes some of the most profound mysteries fundamental physics has encountered in decades, opening the door to the next phase of experimental exploration. More than ever, this will necessitate…
Given the current absence of new physics signals at the LHC, it is increasingly important to investigate alternative scenarios beyond those commonly explored. In this work, we study a variant of the 331 model that predicts the existence of…
Exotic leptons in large gauge multiplets, appearing in many scenarios beyond the Standard Model (SM), can be produced at the LHC in pairs or association. Owing to their large masses, their eventual decay products -- SM leptons and bosons --…
A search is presented for new physics in events with two low-momentum, oppositely charged leptons (electrons or muons) and missing transverse momentum in proton-proton collisions at a centre-of-mass energy of 13 TeV. The data collected…
The High-Luminosity Large Hadron Collider is expected to deliver up to 3000 fb$^{-1}$ of proton-proton collisions at 14 TeV center-of-mass energy. We present prospects for selected heavy-ion, Standard Model and Higgs sector measurements…
The proton-proton collision energy at Large Hadron Collider (LHC) has been 7, 8 and 13 TeV recently with the goal of reaching to 14 TeV which is the maximum capacity of the LHC. However, there is still more physics yet to be explored and…
A combination of searches for the single production of vector-like top quarks ($T$) is presented. These analyses are based on proton$-$proton collisions at $\sqrt{s}=13$ TeV recorded in 2015$-$2018 with the ATLAS detector at the Large…
We study the properties of vectorlike fermions that have the same gauge charges as the Standard Model lepton doublets, but opposite lepton number. These antileptons undergo decays mediated by heavier scalar leptoquarks, while the symmetries…
This M.Sc. thesis describes a search for exotic leptons. The search has been performed using data from the OPAL detector at the Large Electron Positron collider at CERN. The total integrated luminosity was 663 pb$^{-1}$ with center of mass…
Heavy neutral leptons are present in many well-motivated beyond the Standard Model theories, sometimes being accessible at present colliders. Depending on their masses and couplings they could be long-lived and lead to events with displaced…
Recent results from the ATLAS and CMS experiments in searches for prompt signatures of feebly interacting particles are presented. All presented results are based on the 2015-2018 data set of $13\,\mathrm{TeV}$ proton-proton collisions,…
Both e+e- and {\mu}+{\mu}- colliders have been proposed as possible candidates for a lepton collider to complement and extend the reach of the Large Hadron Collider (LHC) at CERN. The physics program that could be pursued by a new lepton…
Heavy vector-like quarks with electric charge $Q=2/3$ (also called \textit{heavy tops}) appear naturally in many extensions of the Standard Model. Although these typically predict the existence of further particles below the TeV scale,…
Doubly charged scalars are common figures in several beyond the Standard Model studies, especially those related to neutrino masses. In this work, we estimate the High-Luminosity (HL-LHC) and High-Energy LHC (HE-LHC) sensitivity to doubly…