11,983 research outputs found
Radiative Neutrino Mass with Dark matter: From Relic Density to LHC Signatures
In this work we give a comprehensive analysis on the phenomenology of a
specific dark matter (DM) model in which neutrino mass is
induced at two loops by interactions with a DM particle that can be a complex
scalar or a Dirac fermion. Both the DM properties in relic density and direct
detection and the LHC signatures are examined in great detail, and indirect
detection for gamma-ray excess from the Galactic Center is also discussed
briefly. On the DM side, both semi-annihilation and co-annihilation processes
play a crucial role in alleviating the tension of parameter space between relic
density and direct detection. On the collider side, new decay channels
resulting from particles lead to distinct signals at LHC.
Currently the trilepton signal is expected to give the most stringent bound for
both scalar and fermion DM candidates, and the signatures of fermion DM are
very similar to those of electroweakinos in simplified supersymmetric models.Comment: 40 pages, 24 figure
Dimensional and structural stability of gamma irradiated stacked die quad flat no leads (QFN)
The physical properties and structural stability of the Quad Flat No-Leads (QFN) package with different gamma radiation doses have been investigated. The packages were irradiated with Co-60 gamma radiation with varying doses of 5 Gy, 50 Gy, 500 Gy, 5 kGy and 50 kGy with operating dose of 2.54 kGy/h at room temperature. The infinite focus microscope (IFM) was used to measure the dimensional change and slanting/warpage behaviour, while the 3D CT Scan X-ray machine was used to determine the occurrence of deflection on a wire in package due to exposure. It is believed that radiation effect on ceramic filler in the epoxy mold compound (EMC) plays an important role to induce the defects and resulted in swelling of the package. The slanting/warpage behaviour is believed to be caused by the swelling behaviour of ceramic filler and further induced structural stability. The induced stress on the EMC structural after the dimensional change and slanting/warpage failure leads to the occurrence of wire sweep. The finding suggests that defect production in swelled ceramic filler leads to the occurrence of dimensional and structure instability
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