A search for narrow, high-mass resonances decaying to electron or muon pairs has been performed using pp collision data collected at root s = 7 TeV 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'(psi) resonance, 890 (540) GeV for the Stueckelberg extension Z'(St) the mass parameter epsilon = 0.06 (0.04), and 2140 (1810) GeV for Kaluza-Klein gravitons with the coupling parameter k/(M) over bar (Pl) of 0.10 (0.05). These limits are the most stringent to date. (C) 2012 Elsevier B.V. All rights reserved.
Search for narrow resonances in dilepton mass spectra in pp collisions at root s=7 TeV
ABBRESCIA, Marcello;CALABRIA, CESARE;DE PALMA, Mauro;MY, Salvatore;NUZZO, Salvatore Vitale;POMPILI, ALEXIS;SELVAGGI, Giovanna;
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 root s = 7 TeV 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'(psi) resonance, 890 (540) GeV for the Stueckelberg extension Z'(St) the mass parameter epsilon = 0.06 (0.04), and 2140 (1810) GeV for Kaluza-Klein gravitons with the coupling parameter k/(M) over bar (Pl) of 0.10 (0.05). These limits are the most stringent to date. (C) 2012 Elsevier B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
