arXiv subjects

Bruno Lenzi

Publications and source records attributed to Bruno Lenzi.

4 recordsLinked to original sources

arXiv2016

Search for a high mass diphoton resonance using the ATLAS detector

A search for new spin-0 resonances decaying into two photons in the ATLAS experiment at the LHC is described. The analysis is based on $pp$ collision data at $\sqrt{s}$=13 TeV corresponding to integrated luminosities of 3.2/fb and 12.2/fb recorded in 2015 and 2016, respectively. A deviation from the Standard Model background-only hypothesis corresponding to 3.4 standard deviations is observed in the 2015 data for a resonance mass hypothesis of 730 GeV. No significant excess at such mass over the background expectation is observed in the 2016 data. Limits on the production cross section times branching ratio to two photons of such resonances are reported.

hep-ex↗

arXiv2016

Light-by-light scattering with intact protons at the LHC: from Standard Model to New Physics

We discuss the discovery potential of light-by-light scattering at the Large Hadron Collider (LHC), induced by the Standard Model (SM) and by new exotic charged particles. Our simulation relies on intact proton detection in the planned forward detectors of CMS and ATLAS. The full four-photon amplitudes generated by any electrically charged particles of spins $1/2$ and $1$, including the SM processes involving loops of leptons, quarks and $W$ bosons are implemented in the Forward Physics Monte Carlo generator. Our method provides model-independent bounds on massive charged particles, only parametrized by the spin, mass and "effective charge" $Q_{\rm eff}$ of the new particle. We find that a new charged vector (fermion) with $Q_{\rm eff}=4$ can be discovered up to $m=640~\rm GeV$ ($m=300~\rm GeV$) with an integrated luminosity of $300~\rm fb^{-1}$ at the LHC. We also discuss the sensitivities to neutral particles such as a strongly-interacting heavy dilaton and warped Kaluza-Klein gravitons, whose effects could be discovered for masses in the multi-TeV range.

hep-ph↗

arXiv2014

Measurement of properties of the Higgs boson in bosonic decay channels using the ATLAS detector

The properties of the Higgs boson measured in bosonic decay channels ($H \rightarrow γγ$, $H \rightarrow ZZ^* \rightarrow 4\ell$, $H \rightarrow WW^{*} \rightarrow \ellν\ellν$, $H \rightarrow Zγ$) with 25 fb$^{-1}$ of pp collision data from the Large Hadron Collider run-1 collected by the ATLAS experiment are presented. The results include an improved measurement of the mass of the Higgs boson from a combined fit to the invariant mass spectra of the decay channels $H \rightarrow γγ$ and $H \rightarrow ZZ^* \rightarrow 4\ell$, which yields $m_H = 125.36 \pm 0.37$ (stat) $\pm 0.18$ (syst) GeV = $125.36 \pm 0.41$ GeV and supersedes the previous result from ATLAS.

hep-ex↗

arXiv2008

Search for the Standard Model Higgs boson decaying to four lepton (muon, electron) final states with the ATLAS experiment at the LHC collider

The search for the Standard Model Higgs boson in the four lepton (electron and muon) final state with the ATLAS detector at the LHC is presented. The analysis strategy and the efficiency for selecting the signal and rejecting the background are discussed, focusing on the performance of the lepton identification that can be achieved with the first data of LHC expected in 2008.

hep-ex↗