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Title: Search for long-lived particles that decay into final states containing two electrons or two muons in proton-proton collisions at $$\sqrt{s} =$$ 8 TeV

A search is performed for long-lived particles that decay into final states that include a pair of electrons or a pair of muons. The experimental signature is a distinctive topology consisting of a pair of charged leptons originating from a displaced secondary vertex. Events corresponding to an integrated luminosity of 19.6 (20.5) fb–1 in the electron (muon) channel were collected with the CMS detector at the CERN LHC in proton-proton collisions at √s=8 TeV. No significant excess is observed above standard model expectations. Upper limits on the product of the cross section and branching fraction of such a signal are presented as a function of the long-lived particle’s mean proper decay length. The limits are presented in an approximately model-independent way, allowing them to be applied to a wide class of models yielding the above topology. Over much of the investigated parameter space, the limits obtained are the most stringent to date. In the specific case of a model in which a Higgs boson in the mass range 125–1000 GeV/c2 decays into a pair of long-lived neutral bosons in the mass range 20–350 GeV/c2, each of which can then decay to dileptons, the upper limits obtained are typically in themore » range 0.2–10 fb for mean proper decay lengths of the long-lived particles in the range 0.01–100 cm. In the case of the lowest Higgs mass considered (125 GeV/c2), the limits are in the range 2–50 fb. As a result, these limits are sensitive to Higgs boson branching fractions as low as 10–4.« less
  1. Yerevan Physics Inst. (YerPhI), Yerevan (Armenia). et al.
Publication Date:
OSTI Identifier:
Report Number(s):
FERMILAB-PUB-14-535-CMS; CERN-PH-EP-2014-263; CMS-EXO-12-037
Journal ID: ISSN 1550-7998; PRVDAQ; arXiv eprint number arXiv:1411.6977
Grant/Contract Number:
Published Article
Journal Name:
Physical Review. D, Particles, Fields, Gravitation and Cosmology
Additional Journal Information:
Journal Volume: 91; Journal Issue: 5; Journal ID: ISSN 1550-7998
American Physical Society (APS)
Research Org:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Contributing Orgs:
CMS Collaboration
Country of Publication:
United States