44 research outputs found
Performance Evaluation at the System Level of Reconfigurable Space-Time Coding Techniques for HSDPA
No full text A reconfigurable space-time coding technique is investigated, for a high-speed downlink packet access multiple-antenna network, which combats the effects of antenna correlation. Reconfigurability is achieved at the link level by introducing a linear precoder in a space-time block coded system. The technique assumes knowledge of the long-term characteristics of the channel, namely the channel correlation matrix at the transmitter. The benefits of the proposed reconfigurable technique as compared to the conventional non-reconfigurable versions are evaluated via system-level simulations. In order to characterize the system-level performance accurately and, at the same time, use a feasible approach in terms of computational complexity, a suitable link-to-system interface has been developed. The average system throughput and the number of satisfied users are the performance metrics of interest. Simulation results demonstrate the performance enhancements achieved by the application of reconfigurable techniques as compared to their conventional counterparts.</p
Author Correction: A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery
No full textIn the version of this article initially published, the ATLAS Collaboration
author names, affiliations and acknowledgements were omitted and
have now been included in the HTML and PDF versions of the article
Search for Majorana neutrinos in same-sign scattering events from collisions at TeV
No full textA search for Majorana neutrinos in same-sign scattering events is
presented. The analysis uses TeV proton-proton collision data
with an integrated luminosity of 140 fb recorded during 2015-2018 by the
ATLAS detector at the Large Hadron Collider. The analysis targets final states
including exactly two same-sign muons and at least two hadronic jets well
separated in rapidity. The modelling of the main backgrounds, from Standard
Model same-sign scattering and production, is constrained with data
in dedicated signal-depleted control regions. The distribution of the
transverse momentum of the second-hardest muon is used to search for signals
originating from a heavy Majorana neutrino with a mass between 50 GeV and 20
TeV. No significant excess is observed over the background expectation. The
results are interpreted in a benchmark scenario of the Phenomenological Type-I
Seesaw model. In addition, the sensitivity to the Weinberg operator is
investigated. Upper limits at the 95% confidence level are placed on the
squared muon-neutrino-heavy-neutrino mass-mixing matrix element as a function of the heavy Majorana neutrino's mass , and on
the effective Majorana neutrino mass .Comment: 37 pages in total, author list starting page 19, 3 figures, 1 table.
All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2020-06
Isospin dependence of electromagnetic transition strengths among an isobaric triplet
No full text© 2019 The Author(s) Electric quadrupole matrix elements, Mp, for the Jπ=2+→0+, ΔT=0, T=1 transitions across the A=46 isobaric multiplet 46Cr-46V-46Ti have been measured at GSI with the FRS-LYCCA-AGATA setup. This allows direct insight into the isospin purity of the states of interest by testing the linearity of Mp with respect to Tz. Pairs of nuclei in the T=1 triplet were studied using identical reaction mechanisms in order to control systematic errors. The Mp values were obtained with two different methodologies: (i) a relativistic Coulomb excitation experiment was performed for 46Cr and 46Ti; (ii) a “stretched target” technique was adopted here, for the first time, for lifetime measurements in 46V and 46Ti. A constant value of Mp across the triplet has been observed. Shell-model calculations performed within the fp shell fail to reproduce this unexpected trend, pointing towards the need of a wider valence space. This result is confirmed by the good agreement with experimental data achieved with an interaction which allows excitations from the underlying sd shell. A test of the linearity rule for all published data on complete T=1 isospin triplets is presented
Nuclear spectroscopy near the proton drip linein the lanthanide region: The 122La nucleus
No full textExcited states in the very neutron-deficient 122La nucleus have been established for the first time using the 92Mo(40Ca, 2α1p1n) reaction at beam energies of 190 and 200MeV. The observed transitions were grouped in three bands. Configurations have been assigned to the observed bands based on the properties extracted from the experimental data and on cranked shell model calculations
