Search for new heavy stable particles at the LHC

Project leader

Funding source

Swedish Research Council - Vetenskapsrådet (VR)

Project Details

Start date: 01/01/2016
End date: 31/12/2019
Funding: 2172000 SEK


It is proposed that searches be made at the upgraded ATLAS experiment during run 2 of the CERN Large Hadron Collider (LHC) for a class of hitherto unobserved particles: stable, massive particles (SMPs). The possible signature of a long-lived particle is an important observable in the search for new physics. In this application, it is proposed that, using common techniques, two broad classes of SMPs are sought. Searches will be made for SMPs anticipated at the TeV scale in theories beyond the Standard Model (SM) of particle physics, eg R-hadrons, as well as "blue sky" searches for SMPs with anomalous values of electric and magnetic charge. The main focus of the worldwide collider particle physics commnity is the LHC. From 2015 onwards, the LHC run 2 will deliver proton-proton collisions at the world's highest centre-of-mass energies - 13-14 TeV and with luminosity values far in excess of that delivered for run 1. An important goal of the LHC program is to explore the TeV scale for new phenomena. Run 2 opens a new discovery window for new physics in both mass scale and precision. Expectations of new phenomena aere motivated by theoretical arguments, eg the hierarchy problem, and by the inability of the Standard Model to address physical phenomena, such as dark matter. SMPs are predicted in a range of scenarios of new physics processes, such models of supersymmetry, leptoquarks and extra dimensions. It is proposed that the ATLAS detector, recently upgraded, be used to look for SMPs. Discriminants such as continuous ionisation energy loss and calorimeter timing will be used to suppress background. Techniques will be developed to suppress the impact of "pile up" events on the key signature observables. Sensitivity to SMP production cross sections will increase by over a factor two compared with run 1 searches, enabling either discovery and quantification of the properties of SMPs or the world's most stringent limits. Preparatory work will also be done to further increase SMP-sensitivity during the later LHC run 3. In addition to the experimental measurements, it is also proposed that interpretation studies take place of the body of LHC SMP results within the context of R-parity violating supersymmetry.

Last updated on 2017-28-07 at 07:38