A search for heavy, long-lived, charged particles with large ionization energy loss
within the silicon tracker of the CMS experiment is presented. A data set of proton-proton
collisions at a center of mass energy at √s = 13 TeV, collected in 2017 and 2018 at the CERN
LHC, corresponding to an integrated luminosity of 101 fb−1, is used in this analysis. Two
diferent approaches for the search are taken. A new method exploits the independence of
the silicon pixel and strips measurements, while the second method improves on previous
techniques using ionization to determine a mass selection. No signifcant excess of events
above the background expectation is observed. The results are interpreted in the context
of the pair production of supersymmetric particles, namely gluinos, top squarks, and tau
sleptons, and of the Drell-Yan pair production of fourth generation (τ) leptons with an electric
charge equal to or twice the absolute value of the electron charge (e). An interpretation
of a Z’ boson decaying to two τ leptons with an electric charge equal to 2e is presented
for the frst time. The 95% confdence upper limits on the production cross section are
extracted for each of these hypothetical particles.
