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.

Search for dark matter candidates and large extra dimensions in events with a jet and missing transverse momentum with the ATLAS detector

Abstract: A search for new phenomena in events with a high-energy jet and large missing transverse momentum is performed using data from proton-proton collisions at root s = 7 TeV with the ATLAS experiment at the Large flatiron Collider. Four kinematic regions are explored using a dataset corresponding to an integrated luminosity of 4.7 fb(-1). No excess of events beyond expectations from Standard Model processes is observed, and limits are set on large extra dimensions and the pair production of dark matter particles.

Chandra Discovery of a Tree in the X-Ray Forest toward PKS 2155–304: The Local Filament?

Abstract: We present the first X-ray detection of resonant absorption from warm/hot local gas either in our Galaxy, or in the intergalactic space surrounding our Galaxy, along the line of sight toward the blazar PKS 2155-304. The Chandra HRCS/LETG spectrum of this z = 0.116 source clearly shows, at ≥5 σ level, unresolved (FWHM ≤ 800 km s-1 at a 2 σ confidence level) O VII Kα and Ne IX Kα resonant absorption lines at 21.603 and 13.448 A (i.e., cz = 14 km s-1 in the rest frame, from the O VII Kα line). O VIII Kα and O VII Kβ from the same system are also detected at a lower significance level (i.e., ~3 σ), while upper limits are set on O VIII Kβ, Ne X Kα, and Ne IX Kβ. The Far Ultraviolet Spectroscopic Explorer spectrum of this source shows complex O VI 2s→2p absorption at the same redshift as the X-ray system, made by at least two components: one relatively narrow (FWHM = 106 ± 9 km s-1) and slightly redshifted (cz = 36 ± 6 km s-1), and one broader (FWHM = 158 ± 26 km s-1) and blueshifted (cz = -135 ± 14 km s-1). We demonstrate that the physical states of the UV and X-ray absorbers are hard to reconcile with a single, purely collisionally ionized, equilibrium plasma. We propose instead that the X-ray and at least the broader and blueshifted UV absorber are produced in a low-density intergalactic plasma, collapsing toward our Galaxy, consistent with the predictions of a warm-hot intergalactic medium from numerical simulations. We find that any reasonable solution requires overabundance of Ne compared to O by a factor of ~2, with respect to the solar value. We propose several scenarios to account for this observation.

L-Thyroxine vs. 3,5,3'-triiodo-L-thyronine and cell proliferation: activation of mitogen-activated protein kinase and phosphatidylinositol 3-kinase.

Abstract: 3,5,3'-Triiodo-l-thyronine (T(3)), but not l-thyroxine (T(4)), activated Src kinase and, downstream, phosphatidylinositol 3-kinase (PI3-kinase) by means of an alpha(v)beta(3) integrin receptor on human glioblastoma U-87 MG cells. Although both T(3) and T(4) stimulated extracellular signal-regulated kinase (ERK) 1/2, activated ERK1/2 did not contribute to T(3)-induced Src kinase or PI3-kinase activation, and an inhibitor of PI3-kinase, LY-294002, did not block activation of ERK1/2 by physiological concentrations of T(3) and T(4). Thus the PI3-kinase, Src kinase, and ERK1/2 signaling cascades are parallel pathways in T(3)-treated U-87 MG cells. T(3) and T(4) both caused proliferation of U-87 MG cells; these effects were blocked by the ERK1/2 inhibitor PD-98059 but not by LY-294002. Small-interfering RNA knockdown of PI3-kinase confirmed that PI3-kinase was not involved in the proliferative action of T(3) on U-87 MG cells. PI3-kinase-dependent actions of T(3) in these cells included shuttling of nuclear thyroid hormone receptor-alpha (TRalpha) from cytoplasm to nucleus and accumulation of hypoxia-inducible factor (HIF)-1alpha mRNA; LY-294002 inhibited these actions. Results of studies involving alpha(v)beta(3) receptor antagonists tetraiodothyroacetic acid (tetrac) and Arg-Gly-Asp (RGD) peptide, together with mathematical modeling of the kinetics of displacement of radiolabeled T(3) from the integrin by unlabeled T(3) and by unlabeled T(4), are consistent with the presence of two iodothyronine receptor domains on the integrin. A model proposes that one site binds T(3) exclusively, activates PI3-kinase via Src kinase, and stimulates TRalpha trafficking and HIF-1alpha gene expression. Tetrac and RGD peptide both inhibit T(3) action at this site. The second site binds T(4) and T(3), and, via this receptor, the iodothyronines stimulate ERK1/2-dependent tumor cell proliferation. T(3) action here is inhibited by tetrac alone, but the effect of T(4) is blocked by both tetrac and the RGD peptide.

Search for an additional, heavy Higgs boson in the H → ZZ decay channel at √s = 8 TeV in pp collision data with the ATLAS detector

Abstract: A search is presented for a high-mass Higgs boson in the , , , and decay modes using the ATLAS detector at the CERN Large Hadron Collider. The search uses proton-proton collision data at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 20.3 fb. The results of the search are interpreted in the scenario of a heavy Higgs boson with a width that is small compared with the experimental mass resolution. The Higgs boson mass range considered extends up to for all four decay modes and down to as low as 140 , depending on the decay mode. No significant excess of events over the Standard Model prediction is found. A simultaneous fit to the four decay modes yields upper limits on the production cross-section of a heavy Higgs boson times the branching ratio to boson pairs. 95 % confidence level upper limits range from 0.53 pb at GeV to 0.008 pb at GeV for the gluon-fusion production mode and from 0.31 pb at GeV to 0.009 pb at GeV for the vector-boson-fusion production mode. The results are also interpreted in the context of Type-I and Type-II two-Higgs-doublet models.

Quest for precision in hadronic cross sections at low energy: Monte Carlo tools vs. experimental data

Abstract: We present the achievements of the last years of the experimental and theoretical groups working on hadronic cross section measurements at the low energy e+e- colliders in Beijing, Frascati, Ithaca, Novosibirsk, Stanford and Tsukuba and on tau decays. We sketch the prospects in these fields for the years to come. We emphasise the status and the precision of the Monte Carlo generators used to analyse the hadronic cross section measurements obtained as well with energy scans as with radiative return, to determine luminosities and tau decays. The radiative corrections fully or approximately implemented in the various codes and the contribution of the vacuum polarisation are discussed.