Visualizing Correlation Regions: The Case of the Ammonia Crystal

We resort to X-ray constrained wavefunctions in order to separately analyze crystal field and correlation effects in ammonia. With this aim in mind, we compare the electron density and the amount of electron localization in different molecular regions derived from three different calculations: the isolated molecule, the solid-state and the X-ray constrained wavefunctions. While the crystal field effects lead to a contraction (localization) of electron pairs, the introduction of correlation as a correction from the experimental density leads to a compensating effect that diffuses back again the electron pairs. We have also compared the effect on the most widely used methods in solid state, HF and DFT, showing that (as in molecules) correlation has well differenciated effects, with DFT overdelocalizing. It is now well known that approximate functionals have errors in the density reconstruction and in the energy estimation. Resorting to experimental densities thus allows expanding the separation of the errors in the functional and the density in solid state, where correlated wavefunctions are not easily available

Experimental data in support of characterization of the CePO4 dispersion into transparent PMMA/PU IPNs by the sequential route

© 2018 This article is focused on the complementary data referring to the article “Dispersion of upconverting nanostructures of CePO4 using rod and semi-spherical morphologies into transparent PMMA/PU IPNs by the sequential route”. It contains the XPS data of CePO4 photographs and DSC thermograms of transparent PMMA/PU IPNs as well as with CePO4 dispersed in different wt.%, Confocal laser scanning micrographs, transmission electron microscopy (TEM), optical images of surface, and visual inspection (photographs) before and after aging of hybrid materials

Dispersion of upconverting nanostructures of CePO4 using rod and semi-spherical morphologies into transparent PMMA/PU IPNs by the sequential route

Upconverting luminescent poly (methylmethacrylate) (PMMA)/poly (urethane) (PU) interpenetrating polymer network (IPN) nanohybrids were prepared using a sequential polymerisation incorporating different wt.% of cerium phosphate (CePO 4 ) nanoparticles. The effect of miscibility/compatibility of the different PMMA/PU ratios, the addition and dispersion of rod and semi-spherical nanostructures in as well as the performance of selected IPNs under accelerated aging were studied using morphological, emission, thermal and mechanical studies. Structural studies revealed that there were physical interactions between C[dbnd]O groups and CePO 4 in PMMA/PU IPNs. The addition of a higher wt.% of nanostructures was found to decrease the transparency of the IPNs. Resulting PMMA/PU/CePO 4 IPN nanohybrids are photoluminescent under UV-light, supporting the prolongate of lifetime while maintaining the mechanical properties after being subjected to accelerated weathering. The addition of semi-spherical particles resulted in a more stable materials after accelerated weathering than nanorods

Near-infrared photometry and spectroscopy of the low Galactic latitude globular cluster 2MASS-GC03

We present deep near-infrared photometry and spectroscopy of the globular cluster 2MASS-GC03 projected in the Galactic disk using MMIRS on the Clay telescope (Las Campanas Observatory) and VISTA Variables in the Via Lactea survey (VVV) data. Most probable cluster member candidates were identified from near-infrared photometry. Out of ten candidates that were followed-up spectroscopically, five have properties of cluster members, from which we calculate = -0.9 +/- 0.2 and a radial velocity of v_r > = -78 +- 12km/s. A distance of 10.8kpc is estimated from 3 likely RRLyrae members. Given that the cluster is currently at a distance of 4.2kpc from the Galactic center, the cluster's long survival time of an estimated 11.3 +/- 1.2 Gyr strengthens the case for its globular-cluster nature. The cluster has a hint of elongation in the direction of the Galactic center.Peer reviewedFinal Published versio

First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data

Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signalto- noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have been developed, allowing a fully coherent search for gravitational waves from known pulsars over a fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of 11 pulsars using data from Advanced LIGO’s first observing run. Although we have found several initial outliers, further studies show no significant evidence for the presence of a gravitational wave signal. Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for the first time. For an additional 3 targets, the median upper limit across the search bands is below the spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried out so far

Search for New Physics with Jets and Missing Transverse Momentum in pp collisions at sqrt(s) = 7 TeV

A search for new physics is presented based on an event signature of at least three jets accompanied by large missing transverse momentum, using a data sample corresponding to an integrated luminosity of 36 inverse picobarns collected in proton--proton collisions at sqrt(s)=7 TeV with the CMS detector at the LHC. No excess of events is observed above the expected standard model backgrounds, which are all estimated from the data. Exclusion limits are presented for the constrained minimal supersymmetric extension of the standard model. Cross section limits are also presented using simplified models with new particles decaying to an undetected particle and one or two jets

Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

Search for anomalous t t-bar production in the highly-boosted all-hadronic final state

A search is presented for a massive particle, generically referred to as a Z', decaying into a t t-bar pair. The search focuses on Z' resonances that are sufficiently massive to produce highly Lorentz-boosted top quarks, which yield collimated decay products that are partially or fully merged into single jets. The analysis uses new methods to analyze jet substructure, providing suppression of the non-top multijet backgrounds. The analysis is based on a data sample of proton-proton collisions at a center-of-mass energy of 7 TeV, corresponding to an integrated luminosity of 5 inverse femtobarns. Upper limits in the range of 1 pb are set on the product of the production cross section and branching fraction for a topcolor Z' modeled for several widths, as well as for a Randall--Sundrum Kaluza--Klein gluon. In addition, the results constrain any enhancement in t t-bar production beyond expectations of the standard model for t t-bar invariant masses larger than 1 TeV.Comment: Submitted to the Journal of High Energy Physics; this version includes a minor typo correction that will be submitted as an erratu