8,367 research outputs found
Observation of recoil-induced resonances and electromagnetically induced absorption of cold atoms in diffuse light
In this paper we report an experiment on the observation of the
recoil-induced resonances (RIR) and electromagnetically induced absorption
(EIA) of cold Rb87 atoms in diffuse light. The pump light of the RIR and the
EIA comes from the diffuse light in an integrating sphere, which also serves
the cooling light. The probe light beam is a weak laser split from the cooling
laser in order to keep the cooling and probe lasers correlated. We measured the
RIR and the EIA signal varying with the detuning of the diffuse laser light,
and also measured the temperature of the cold atoms at the different detunings.
The mechanism of RIR and EIA in the configuration with diffuse-light pumping
and laser probing is discussed, and the difference of nonlinear spectra of cold
atoms between in diffuse-light cooling system and in optical molasses as well
as in a magneto-optical trap (MOT) are studied.Comment: 9 pages, 6 figure
catena-Poly[[diaquabis(2-ethyl-1H-imidazole-κN 3)cadmium]-μ-sulfato-κ2 O:O′]
In the title one-dimensional coordination polymer, [Cd(SO4)(C5H8N2)2(H2O)2]n, the CdII atom (site symmetry 2) is coordinated by two sulfate O atoms, two water molecules and two 2-ethylimidazole ligands in a distorted cis-CdN2O4 octahedral geometry. The water molecules have a cis disposition. The bridging sulfate ions (site symmetry 2) link the CdII ions into a polymeric chain extending along [001]. The chains are linked by N—H⋯O and O—H⋯O hydrogen bonds. The terminal –CH3 group of the ligand is disordered over two orientations in a 0.61 (5):0.39 (5) ratio
1H-Pyrazol-2-ium hydrogen oxalate
In the title compound, C3H5N2
+·C2HO4
−, the anions form centrosymmetric dimers through cyclic O—H⋯O hydrogen-bonding associations [graph set R
2
2(10)]. These dimers are then linked through a cyclic R
4
2(10) N—H⋯O hydrogen-bonding association involving two cations and the carboxyl O-atom acceptors of separate anions, giving chain structures extending across the (111) plane
Precise QCD predictions on top quark pair production mediated by massive color octet vector boson at hadron colliders
We present a theoretical framework for systematically calculating
next-to-leading order (NLO) QCD effects to various experimental observables in
models with massive COVB in a model independent way at hadron colliders.
Specifically, we show the numerical results for the NLO QCD corrections to
total cross sections, invariant mass distribution and AFB of top quark pairs
production mediated by a massive COVB in both the fixed scale (top quark mass)
scheme and the dynamical scale (top pair invariant mass) scheme. Our results
show that the NLO QCD calculations in the dynamical scale scheme is more
reasonable than the fixed scheme and the naive estimate of the NLO effects by
simple rescaling of the LO results with the SM NLO K-factor is not appropriate.Comment: 6 pages, 5 figures, 2 tables; version published in EPJ
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