Abstract
This Letter presents a search for the production of a long-lived neutral particle (Z_{d}) decaying within the ATLAS hadronic calorimeter, in association with a standard model (SM) Z boson produced via an intermediate scalar boson, where Z→ℓ^{+}ℓ^{-} (ℓ=e, μ). The data used were collected by the ATLAS detector during 2015 and 2016 pp collisions with a center-of-mass energy of sqrt[s]=13 TeV at the Large Hadron Collider and correspond to an integrated luminosity of 36.1±0.8 fb^{-1}. No significant excess of events is observed above the expected background. Limits on the production cross section of the scalar boson times its decay branching fraction into the long-lived neutral particle are derived as a function of the mass of the intermediate scalar boson, the mass of the long-lived neutral particle, and its cτ from a few centimeters to one hundred meters. In the case that the intermediate scalar boson is the SM Higgs boson, its decay branching fraction to a long-lived neutral particle with a cτ approximately between 0.1 and 7m is excluded with a 95%confidence level up to 10% for m_{Z_{d}} between 5 and 15GeV.
Highlights
Data Expected UL Observed UL13.2 Æ 3.5 16 10 13 a validation jet is measured in the W þ jets sample as a function of jet ET and η and subsequently used to predict the number of events containing a Z → ll candidate and at least one validation jet
The number of selected events containing a CR jet with an ET above a chosen threshold is compared with the predicted total number of background events
Simulations to the number of generated signal events. It is a function of mΦ, mZd, and the cτðZdÞ
Summary
According to the bunch crossing clock, relative to the expected time of flight from the bunch crossing to the cell [39] After this selection, the number of selected events containing a CR jet with an ET above a chosen threshold is compared with the predicted total number of background events. The signal efficiency times acceptance (ε × A) is defined as the ratio of the number of selected signal events in MC simulations to the number of generated signal events. It is a function of mΦ, mZd, and the cτðZdÞ. Potential signal contamination of this control region was estimated using MC and found to have a
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
