Abstract
A search for highly ionizing particles produced in proton-proton collisions at 8 TeV center-of-mass energy is performed by the ATLAS collaboration at the CERN Large Hadron Collider. The dataset used corresponds to an integrated luminosity of 7.0 fb$^{-1}$. A customized trigger significantly increases the sensitivity, permitting a search for such particles with charges and energies beyond what was previously accessible. No events were found in the signal region, leading to production cross section upper limits in the mass range 200--2500 GeV for magnetic monopoles with magnetic charge in the range $0.5g_{D}<|g|<2.0g_{D}$, where $g_{D}$ is the Dirac charge, and for stable particles with electric charge in the range $10<|z|<60$. Model-dependent limits are presented in given pair-production scenarios, and model-independent limits are presented in fiducial regions of particle energy and pseudorapidity.
Highlights
The multi-TeV energy regime accessible at the CERNLarge Hadron Collider (LHC) enables the exploration of uncharted territories of particle physics
This paper presents a dedicated search for a long-lived highly ionizing particle (HIP)
Since energy loss by bremsstrahlung and eþe− pair production is negligible for HIPs, the ionization energy deposit in the EM calorimeter is narrower than that associated with electrons and photons, which induce an EM shower
Summary
Large Hadron Collider (LHC) enables the exploration of uncharted territories of particle physics. Since energy loss by bremsstrahlung and eþe− pair production is negligible for HIPs, the ionization energy deposit in the EM calorimeter is narrower than that associated with electrons and photons, which induce an EM shower This stopping signature applies to HIPs with charge jzj ≳ 10, while particles with lower charges have been probed at ATLAS and CMS using a muon-like signature [30,31]. Further improvements with respect to the previous analyses include a larger integrated luminosity, higher center-of-mass energy, extension of the signal acceptance to the detector forward regions (pseudorapidity [32] up to jηj 1⁄4 2), interpretation for a magnetic charge jgj up to twice the Dirac charge as well as for an electric charge jzj between 20 and 60, and an interpretation for spin-0 HIPs in addition to spin-1=2 for the model-dependent limits
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