Abstract
A search is presented for long-lived particles with a mass between 25 and 50 mathrm{GeV}/mathrm{c}^{2} and a lifetime between 1 and 200mathrm{,ps} in a sample of proton–proton collisions at a centre-of-mass energy of sqrt{s}=7 TeV, corresponding to an integrated luminosity of 0.62 text{ fb }^{-1}, collected by the LHCb detector. The particles are assumed to be pair-produced by the decay of a standard model-like Higgs boson. The experimental signature of the long-lived particle is a displaced vertex with two associated jets. No excess above the background is observed and limits are set on the production cross-section as a function of the long-lived particle mass and lifetime.
Highlights
A variety of models for physics beyond the standard model (SM) feature the existence of new massive particles whose coupling to lighter particles is sufficiently small that they are long-lived
This paper reports on a search for πv particles, pairproduced in the decay of a SM-like Higgs particle with a mass of 120 GeV/c2, close to the mass of the scalar boson discovered by the ATLAS and CMS experiments [9,10]
The lower boundary on the mass range arises from the requirement to identify two hadronic jets while the upper boundary is mostly due to the geometric acceptance of the LHCb detector
Summary
A variety of models for physics beyond the standard model (SM) feature the existence of new massive particles whose coupling to lighter particles is sufficiently small that they are long-lived If these massive particles decay to SM particles and have a lifetime between approximately 1 ps and 1 ns, characteristic of weak decays, they can be identified by their displaced decay vertex. The lower boundary on the mass range arises from the requirement to identify two hadronic jets while the upper boundary is mostly due to the geometric acceptance of the LHCb detector. This analysis uses data collected in p√roton–proton ( pp) collisions at a centre-of-mass energy of s = 7 TeV. Similar searches have been reported by the CDF [11], D0 [12], ATLAS [13] and CMS [14] experiments, LHCb has a unique coverage for long-lived particles with relatively small mass and lifetime, because its trigger makes only modest requirements on transverse momentum
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