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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/c 2 decays into a pair of long-lived neutral bosons in the mass range 20–350 GeV/c 2, each of which can then decay to dileptons, the upper limits obtained aremore » typically in the 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/c 2), 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