11,152 research outputs found
A Software-Defined-Radio Platform for Multiple-Input-Multiple-Output Over-The-Air Measurement
This paper presents a 2 × 2 multiple-inputmultiple-output over-the-air (MIMO OTA) measurement system with user-programmable, reconfigurable and real-time signal processing field-programmable gate arrays (FPGAs)-based software-defined radio (SDR) capability. Signal generation and analysis as well as channel emulation are all implemented using vector signal transceivers (VSTs). As a demonstration, we performed the Third Generation Partnership Project (3GPP) two-stage MIMO OTA conducted test using a downlink time division long-term evolution (TD-LTE) duplex scheme. The channel emulation was operated in a stochastic mode. Some preliminary results of the system verification are shown
Charged lepton flavor violating Higgs decays at future colliders
After the discovery of the Higgs boson, several future experiments have been
proposed to study the Higgs boson properties, including two circular lepton
colliders, the CEPC and the FCC-ee, and one linear lepton collider, the ILC. We
evaluate the precision reach of these colliders in measuring the branching
ratios of the charged lepton flavor violating Higgs decays ,
and . The expected upper bounds on the
branching ratios given by the circular (linear) colliders are found to be
, and at 95\% CL, which are improved by
one to two orders compared to the current experimental bounds. We also discuss
the constraints that these upper bounds set on certain theory parameters,
including the charged lepton flavor violating Higgs couplings, the
corresponding parameters in the type-III 2HDM, and the new physics cut-off
scales in the SMEFT, in RS models and in models with heavy neutrinos.Comment: 20 pages, 2 figures (extend the CEPC study to the FCC-ee and the ILC,
and to match the published version
Production of single-charm hadrons by quark combination mechanism in -Pb collisions at TeV
If QGP-like medium is created in -Pb collisions at extremely high
collision energies, charm quarks that move in the medium can hadronize by
capturing the co-moving light quark(s) or anti-quark(s) to form the charm
hadrons. Using light quark spectra extracted from the experimental data
of light hadrons and a charm quark spectrum that is consistent with
perturbative QCD calculations, the central-rapidity data of spectra and
the spectrum ratios for mesons in the low range (
GeV) in minimum-bias -Pb collisions at TeV are well
described by quark combination mechanism in equal-velocity combination
approximation. The ratio in quark combination mechanism
exhibits the typical increase-peak-decrease behavior as the function of
, and the shape of the ratio for GeV is in agreement
with the preliminary data of ALICE collaboration in central rapidity region
and those of LHCb collaboration in forward rapidity region
. The global production of single-charm baryons is quantified using
the preliminary data and the possible enhancement (relative to light flavor
baryons) is discussed. The spectra of ,
in minimum-bias events and those of single-charm hadrons in high-multiplicity
event classes are predicted, which serves as the further test of the possible
change of the hadronization characteristic for low charm quarks in the
small system created in -Pb collisions at LHC energies.Comment: 13 pages, 8 figure
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