A search for narrow, high-mass resonances decaying to electron or muon pairs has been performed using pp collision data collected at s=7TeV by the CMS experiment in 2011. The data sample corresponds to an integrated luminosity of approximately 5 fb -1. The event yields observed in the signal regions are consistent with predictions of the standard model backgrounds, and upper limits on the cross section times branching fraction for a resonance decaying to dileptons are extracted from a shape analysis of the dilepton invariant mass distribution. The resulting mass limits at 95% confidence level are 2330 GeV for the Z ' in the Sequential Standard Model, 2000 GeV for the superstring-inspired Z ψ ' resonance, 890 (540) GeV for the Stueckelberg extension Z St ' with the mass parameter ε=0.06 (0.04), and 2140 (1810) GeV for Kaluza-Klein gravitons with the coupling parameter k/M- Pl of 0.10 (0.05). These limits are the most stringent to date. © 2012 Elsevier B.V.
Search for narrow resonances in dilepton mass spectra in pp collisions at √s=7TeV
Lorenzo Bianchini;Alberto Messineo;Andrea Rizzi;Guido Tonelli;Andrea Carlo Marini;
2012-01-01
Abstract
A search for narrow, high-mass resonances decaying to electron or muon pairs has been performed using pp collision data collected at s=7TeV by the CMS experiment in 2011. The data sample corresponds to an integrated luminosity of approximately 5 fb -1. The event yields observed in the signal regions are consistent with predictions of the standard model backgrounds, and upper limits on the cross section times branching fraction for a resonance decaying to dileptons are extracted from a shape analysis of the dilepton invariant mass distribution. The resulting mass limits at 95% confidence level are 2330 GeV for the Z ' in the Sequential Standard Model, 2000 GeV for the superstring-inspired Z ψ ' resonance, 890 (540) GeV for the Stueckelberg extension Z St ' with the mass parameter ε=0.06 (0.04), and 2140 (1810) GeV for Kaluza-Klein gravitons with the coupling parameter k/M- Pl of 0.10 (0.05). These limits are the most stringent to date. © 2012 Elsevier B.V.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
