Search results for "LEPTON"
showing 10 items of 1512 documents
Beta-decay studies for applied and basic nuclear physics
2020
In this review we will present the results of recent beta-decay studies using the total absorption technique that cover topics of interest for applications, nuclear structure and astrophysics. The decays studied were selected primarily because they have a large impact on the prediction of a) the decay heat in reactors, important for the safety of present and future reactors and b) the reactor electron antineutrino spectrum, of interest for particle/nuclear physics and reactor monitoring. For these studies the total absorption technique was chosen, since it is the only method that allows one to obtain beta decay probabilities free from a systematic error called the Pandemonium effect. The me…
Cross section for bb¯ production via dielectrons in d + Au collisions at √sNN = 200 GeV
2015
We report a measurement of e+e− pairs from semileptonic heavy-flavor decays in d + Au collisions at √sNN = 200 GeV. By exploring the mass and transverse-momentum dependence of the yield, the bottom decay contribution can be isolated from charm, and quantified by comparison to PYTHIA and MC@NLO simulations. The resulting bb¯-production cross section is σdAu bb¯ = 1.37 ± 0.28 (stat) ± 0.46 (syst) mb, which is equivalent to a nucleon-nucleon cross section of σ NN bb = 3.4 ± 0.8 (stat) ± 1.1 (syst) μb. peerReviewed
"Table 7" of "Cross section for $b\bar{b}$ production via dielectrons in d$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV"
2023
$b\bar{b}$ cross section
The NUMEN project @ LNS: Status and perspectives
2017
The NUMEN project aims at accessing experimentally driven information on Nuclear Matrix Elements (NME) involved in the half-life of the neutrinoless double beta decay (0νββ), by high-accuracy measurements of Heavy Ion (HI) induced Double Charge Exchange (DCE) reaction cross sections. In particular, the (18O,18Ne) and (20Ne,20O) reactions are used as tools for β+β+ and β−β− decays, respectively. In the experiments, performed at INFN - Laboratory Nazionali del Sud (LNS) in Catania, the beams are accelerated by the Superconducting Cyclotron (CS) and the reaction ejectiles are detected the MAGNEX magnetic spectrometer. The measured cross sections are challengingly low (a few nb), being the tota…
QCD NLO with Powheg matching and top threshold matching in WHIZARD
2016
We present the status of the automation of NLO processes within the event generator WHIZARD. The program provides an automated FKS subtraction and phase space integration over the FKS regions, while the (QCD) NLO matrix element is accessed via the Binoth Les Houches Interface from an externally linked one-loop program. Massless and massive test cases and validation are shown for several e+e- processes. Furthermore, we discuss work in progress and future plans. The second part covers the matching of the NRQCD prediction with NLL threshold resummation to the NLO continuum top pair production at lepton colliders. Both the S-wave and P-wave production of the top pair are taken into account in t…
Measurement of the top quark charge in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
2013
A measurement of the top quark electric charge is carried out in the ATLAS experiment at the Large Hadron Collider using 2.05 fb[superscript −1] of data at a centre-of-mass energy of 7 TeV. In units of the elementary electric charge, the top quark charge is determined to be 0.64 ± 0.02 (stat.) ± 0.08 (syst.) from the charges of the top quark decay products in single lepton t[¯ over t] candidate events. This excludes models that propose a heavy quark of electric charge −4/3, instead of the Standard Model top quark, with a significance of more than 8σ.
Search for photonic signatures of gauge-mediated supersymmetry in 8TeV pp collisions with the ATLAS detector
2015
A search is presented for photonic signatures motivated by generalized models of gauge-mediated supersymmetry breaking. This search makes use of 20.3 fb[superscript −1] of proton-proton collision data at √s = 8 TeV recorded by the ATLAS detector at the LHC, and explores models dominated by both strong and electroweak production of supersymmetric partner states. Four experimental signatures incorporating an isolated photon and significant missing transverse momentum are explored. These signatures include events with an additional photon, lepton, b-quark jet, or jet activity not associated with any specific underlying quark flavor. No significant excess of events is observed above the Stand…
Recommendations of the LHC Dark Matter Working Group: Comparing LHC searches for dark matter mediators in visible and invisible decay channels and ca…
2019
Physics of the Dark Universe 26, 100377 (2019). doi:10.1016/j.dark.2019.100377
Measurement of dielectron production in central Pb-Pb collisions at √sNN = 2.76 TeV
2019
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. The first measurement of dielectron (e + e −) production in central (0 – 10 %) Pb – Pb collisions at √sNN=2.76TeV at the LHC is presented. The dielectron invariant-mass spectrum is compared to the expected contributions from hadron decays in the invariant-mass range 0 < mee < 3.5 GeV / c2. The ratio of data and the cocktail of hadronic contributions without vacuum ρ0 is measured in the invariant-mass range 0.15 < mee < 0.7 GeV / c2, w…
Excess electronic recoil events in XENON1T
2020
We report results from searches for new physics with low-energy electronic recoil data recorded with the XENON1T detector. With an exposure of 0.65 t-y and an unprecedentedly low background rate of $76\pm2$ events/(t y keV) between 1 and 30 keV, the data enables sensitive searches for solar axions, an enhanced neutrino magnetic moment, and bosonic dark matter. An excess over known backgrounds is observed at low energies and most prominent between 2 and 3 keV. The solar axion model has a 3.4$\sigma$ significance, and a 3D 90% confidence surface is reported for axion couplings to electrons, photons, and nucleons. This surface is inscribed in the cuboid defined by $g_{ae}<3.8 \times 10^{-12}$,…