Roma Tre University

About: Roma Tre University is a education organization based out in Rome, Lazio, Italy. It is known for research contribution in the topics: Large Hadron Collider & Galaxy. The organization has 4434 authors who have published 15352 publications receiving 374888 citations. The organization is also known as: Universita degli Studi Roma Tre & RomaTre.

Molecular outflow and feedback in the obscured quasar XID2028 revealed by ALMA

Abstract: We imaged, with ALMA and ARGOS/LUCI, the molecular gas and dust and stellar continuum in XID2028, which is an obscured quasi-stellar object (QSO) at z = 1.593, where the presence of a massive outflow in the ionised gas component traced by the [OIII]5007 emission has been resolved up to 10 kpc. This target represents a unique test case to study QSO feedback in action at the peak epoch of AGN-galaxy co-evolution. The QSO was detected in the CO(5 − 4) transition and in the 1.3 mm continuum at ~30 and ~20σ significance, respectively; both emissions are confined in the central (<2 kpc) radius area. Our analysis suggests the presence of a fast rotating molecular disc (v ~ 400 km s^(−1)) on very compact scales well inside the galaxy extent seen in the rest-frame optical light (~10 kpc, as inferred from the LUCI data). Adding available measurements in additional two CO transitions, CO(2 − 1) and CO(3 − 2), we could derive a total gas mass of ~10^(10) M⊙, thanks to a critical assessment of CO excitation and the comparison with the Rayleigh–Jeans continuum estimate. This translates into a very low gas fraction (<5%) and depletion timescales of 40–75 Myr, reinforcing the result of atypical gas consumption conditions in XID2028, possibly because of feedback effects on the host galaxy. Finally, we also detect the presence of high velocity CO gas at ~5σ, which we interpret as a signature of galaxy-scale molecular outflow that is spatially coincident with the ionised gas outflow. XID2028 therefore represents a unique case in which the measurement of total outflowing mass, of ~500–800 M⊙ yr^(−1) including the molecular and atomic components in both the ionised and neutral phases, was attempted for a high-z QSO.

Electromagnetic form factor of the pion from twisted-mass lattice QCD at N f =2

Abstract: We present a lattice calculation of the electromagnetic form factor of the pion obtained using the tree-level Symanzik improved gauge action with two flavors of dynamical twisted Wilson quarks. The simulated pion masses range approximately from 260 to 580 MeV, and the lattice box sizes are chosen in order to guarantee that ${M}_{\ensuremath{\pi}}L\ensuremath{\gtrsim}4$. Accurate results for the form factor are obtained using all-to-all quark propagators evaluated by a stochastic procedure. The momentum dependence of the pion form factor is investigated up to values of the squared four-momentum transfer ${Q}^{2}\ensuremath{\simeq}0.8\text{ }\text{ }{\mathrm{GeV}}^{2}$ and, thanks to the use of twisted boundary conditions, down to ${Q}^{2}\ensuremath{\simeq}0.05\text{ }\text{ }{\mathrm{GeV}}^{2}$. Volume and discretization effects on the form factor appear to be within the statistical errors. Our results for the pion mass, decay constant and form factor are analyzed using (continuum) chiral perturbation theory at next-to-next-to-leading order. The extrapolated value of the pion charge radius is $⟨{r}^{2}{⟩}^{\mathrm{phys}}=0.456\ifmmode\pm\else\textpm\fi{}{0.030}_{\mathrm{stat}}\ifmmode\pm\else\textpm\fi{}{0.024}_{\mathrm{syst}}$ in nice agreement with the experimental result. The extrapolated values of the pion form factor agree very well with the experimental data up to ${Q}^{2}\ensuremath{\simeq}0.8\text{ }\text{ }{\mathrm{GeV}}^{2}$ within uncertainties which become competitive with the experimental errors for ${Q}^{2}\ensuremath{\gtrsim}0.3\text{ }\text{ }{\mathrm{GeV}}^{2}$. The relevant low-energy constants appearing in the chiral expansion of the pion form factor are extracted from our lattice data, which come essentially from a single lattice spacing, adding the experimental value of the pion scalar radius in the fitting procedure. Our findings are in nice agreement with the available results of chiral perturbation theory analyses of $\ensuremath{\pi}\ensuremath{-}\ensuremath{\pi}$ scattering data as well as with other analyses of our collaboration.

Entrainment and mixing in unsteady gravity currents

Abstract: Entrainment and mixing in lock-exchange gravity currents are investigated by large eddy simulations. Nine cases are analysed, varying the initial excess density driving the motion and the aspect ratio r of the initial water depth to the lock length. Laboratory experiments are also performed and a fair agreement between numerical simulations and measurements is found. Mixing between the gravity current and the ambient fluid, in both the slumping and self-similar phases, is studied for a range of entrainment parameters, gravity current fractional area and using an energy budget method. The entrainment is found to increase as r decreases. The occurrence of irreversible mixing is detected during the entire development of the flow, i.e. both in the slumping and self-similar phases. A higher amount of mixing is observed as r decreases and the initial excess density increases.

Search for charged Higgs bosons decaying via H±→ τ±ν in fully hadronic final states using pp collision data at √s = 8 TeV with the ATLAS detector

Abstract: The results of a search for charged Higgs bosons decaying to a T lepton and a neutrino. H-+/- -> T-+/-nu, are presented. The analysis is based on 19.5 fb(-1) of proton-proton collision data at r ...

Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at √s = 8 TeV with the ATLAS detector

Abstract: The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30.