8,903 research outputs found
Magnetization non-rational quasi-plateau and spatially modulated spin order in the model of the single-chain magnet, [{(CuL)_2 Dy}{Mo(CN)_8}] 2CH_3CN H_2O
Using the exact solution in terms of the generalized classical transfer
matrix method we presented a detailed analysis of the magnetic properties and
ground state structure of the simplified model of the single-chain magnet,
trimetallic coordination polymer compound, [{(CuL)_2 Dy}{Mo(CN)_8}] 2CH_3CN
H_2O is N,N'-propylenebis(3-methoxysalicylideneiminato). Due to appearance of
highly anisotropic Dy3+ ion this material is an unique example of the
one-dimensional magnets with Ising and Heisenberg bonds, allowing exact
statistical-mechanical treatment. We found two zero-temperature ground states
corresponding to different part of the magnetization curve of the material. The
zero-filed ground state is shown to be an antiferromagnetic configuration with
spatial modulation of the local Dy3+(which is proven to posses well defined
Ising like properties due two large anisotropy of g-factors) and composite
S=1/2 spin of the quantum spin trimer Cu-Mo-Cu in the form
"up"-"down"-"down"-"up". Another important feature of this compound is the
appearance of the quasi-plateau at non rational value of magnetization due to
difference of the g-factors of the Cu- and Mo-ion in quantum spin trimers. The
quasi-plateau is an almost horizontal part of the magnetization curve where the
corresponding zero-temperature ground state of the chain demonstrate slow but
monotonous dependence of the magnetization on the external magnetic field,
while the -projection of the total spin is constant
Using single top rapidity to measure V_td, V_ts, V_tb at hadron colliders
Single top production processes are usually regarded as the ones in which
V_tb can be directly measured at hadron colliders. We show that the analysis of
the single top rapidity distribution in t-channel and tW production can also
set direct limits on V_td. At LHC with 10 fb^-1 at 14 TeV the combined limits
on V_td may be reduced by almost a factor of two when the top rapidity
distribution is used. This also implies that the limits on V_tb can also be
reduced by 15%, since both parameters as well as V_ts must be simultaneously
obtained from a global fit to data. At Tevatron the explotation of this
distribution would require very high statistics.Comment: LaTeX 19 pages, 48 PS figures. A section added with estimations of
systematics, LO/NLO comparison and a fast detector simulation. Final version
to appear in PR
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