27,931 research outputs found
Theoretical investigation of the molecular nature of and and the possibility of observing the bound state in inclusive collisions
Searching for exotic multiquark states and elucidating their nature remains a
central topic in understanding quantum chromodynamics--the underlying theory of
the strong interaction. Two of the most studied such states are the
charm-strange states and . In this letter, we
show for the first time that their prompt production yields in inclusive
collisions near GeV measured by the BABAR
Collaboration, and , in particular the
ratio , can be well explained in the
molecular picture, which provide a highly nontrivial verification of their
nature being molecules. On the contrary, treating them as pure
wave states, the statistical model predicts a ratio smaller
than unity, in contrast with the experimental central value, though in
agreement with it considering its relatively large uncertainty. In addition, we
predict the production yield of the three-body bound state,
, in collisions and find that it is
within the reach of the ongoing Belle II experiment. The present study
demonstrates the feasibility of a novel method to unravel the nature of exotic
hadrons and the potential of electron-positron collisions in this regard.Comment: 8 pages, 3 figures; more discussions and comparison with the
statistical model adde
A Comparative Study on Spin-Orbit Torque Efficiencies from W/ferromagnetic and W/ferrimagnetic Heterostructures
It has been shown that W in its resistive form possesses the largest
spin-Hall ratio among all heavy transition metals, which makes it a good
candidate for generating efficient dampinglike spin-orbit torque (DL-SOT)
acting upon adjacent ferromagnetic or ferrimagnetic (FM) layer. Here we provide
a systematic study on the spin transport properties of W/FM magnetic
heterostructures with the FM layer being ferromagnetic
CoFeB or ferrimagnetic CoTb with
perpendicular magnetic anisotropy. The DL-SOT efficiency , which is
characterized by a current-induced hysteresis loop shift method, is found to be
correlated to the microstructure of W buffer layer in both
W/CoFeB and W/CoTb systems. Maximum values
of and are achieved when
the W layer is partially amorphous in the W/CoFeB and
W/CoTb heterostructures, respectively. Our results suggest that
the spin Hall effect from resistive phase of W can be utilized to effectively
control both ferromagnetic and ferrimagnetic layers through a DL-SOT mechanism
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