4,316 research outputs found
Majorana Neutrino Masses from Neutrinoless Double-Beta Decays and Lepton-Number-Violating Meson Decays
The Schechter-Valle theorem states that a positive observation of
neutrinoless double-beta () decays implies a finite Majorana
mass term for neutrinos when any unlikely fine-tuning or cancellation is
absent. In this note, we reexamine the quantitative impact of the
Schechter-Valle theorem, and find that current experimental lower limits on the
half-lives of -decaying nuclei have placed a restrictive
upper bound on the Majorana neutrino mass radiatively generated at the four-loop level. Furthermore,
we generalize this quantitative analysis of decays to that
of the lepton-number-violating (LNV) meson decays (for , = or ). Given the
present upper limits on these rare LNV decays, we have derived the loop-induced
Majorana neutrino masses ,
and from ,
and ,
respectively. A partial list of radiative neutrino masses from the LNV decays
of , and mesons is also given.Comment: 10 pages, 1 figure, clarification added and references updated, Phys.
Lett. B in pres
Itinerant chiral ferromagnetism in a trapped Rashba spin-orbit coupled Fermi gas
How ferromagnetic phases emerge in itinerant systems is an outstanding
problem in quantum magnetism. Here we consider a repulsive two-component Fermi
gas confined in a two dimensional isotropic harmonic potential and subject to a
large Rashba spin-orbit (SO) coupling, whose single-particle dispersion can be
tailored by adjusting the SO coupling strength. We show that the interplay
among SO coupling, correlation effects and mean-field repulsion leads to a
competition between ferromagnetic and non-magnetic phases. At intermediate
interaction strengths, ferromagnetic phase emerges which can be well described
by the mean-field Hartree-Fock theory; whereas at strong interaction strengths,
a strongly correlated non-magnetic phase is favored due to the
beyond-mean-field quantum correlation effects. Furthermore, the ferromagnetic
phase of this system possesses a chiral current density induced by the Rashba
spin-orbit coupling, whose experimental signature is investigated.Comment: Main text: 5 pages, 6 figures; Supplement: 4 pages, 2 figure
The field coupling mechanism study for near field probe
In this part, the radius of the loop is used to predict the voltage induced by the E- field in the circular loop antenna. The thin rectangle loop and thick rectangle loop have been investigated. The equivalent radius of the rectangle loop is estimated by the average of the one over the distance between the points on the loop to the center of the loop. The estimation matches with the numerical simulation --Abstract, page iv
Experimental study on energy consumption of computer numerical control machine tools
Machining processes are responsible for substantial environmental impacts due to their great energy consumption. Accurately characterizing the energy consumption of machining processes is a starting point to increase manufacturing energy efficiency and reduce their associated environmental impacts. The energy calculation of machining processes depends on the availability of energy supply data of machine tools. However, the energy supply can vary greatly among different types of machine tools so that it is difficult to obtain the energy data theoretically. The aim of this research was to investigate the energy characteristics and obtain the power models of computer numerical control (CNC) machine tools through an experimental study. Four CNC lathes, two CNC milling machines and one machining center were selected for experiments. Power consumption of non-cutting motions and material removal was measured and compared for the selected machine tools. Here, non-cutting motions include standby, cutting fluid spraying, spindle rotation and feeding operations of machine tools. Material removal includes turning and milling. Results show that the power consumption of non-cutting motions and milling is dependent on machine tools while the power consumption of turning is almost independent from the machine tools. The results imply that the energy saving potential of machining processes is tremendous
P3-244: Clinical analysis of adjuvant chemotherapy after radical surgery for stage II non-small cell lung cancer
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