First measurement of Ωc0 production in pp collisions at s=13 TeV

The inclusive production of the charm–strange baryon 0 c is measured for the first time via its hadronic √ decay into −π+ at midrapidity (|y| <0.5) in proton–proton (pp) collisions at the centre-of-mass energy s =13 TeV with the ALICE detector at the LHC. The transverse momentum (pT) differential cross section multiplied by the branching ratio is presented in the interval 2 < pT < 12 GeV/c. The pT dependence of the 0 c-baryon production relative to the prompt D0-meson and to the prompt 0 c-baryon production is compared to various models that take different hadronisation mechanisms into consideration. In the measured pT interval, the ratio of the pT-integrated cross sections of 0 c and prompt + c baryons multiplied by the −π+ branching ratio is found to be larger by a factor of about 20 with a significance of about 4σ when compared to e+e− collisions

Elliptic flow of charged particles at midrapidity relative to the spectator plane in Pb–Pb and Xe–Xe collisions

Measurements of the elliptic flow coefficient relative to the collision plane defined by the spectator neutrons v2{ SP} in collisions of Pb ions at center-of-mass energy per nucleon–nucleon pair √ 2.76 TeV and Xe ions at √ sNN = sNN =5.44 TeV are reported. The results are presented for charged particles produced at midrapidity as a function of centrality and transverse momentum for the 5–70% and 0.2–6 GeV/c ranges, respectively. The ratio between v2{ SP} and the elliptic flow coefficient relative to the participant plane v2{4}, estimated using four-particle correlations, deviates by up to 20% from unity depending on centrality. This observation differs strongly from the magnitude of the corresponding eccentricity ratios predicted by the TRENTo and the elliptic power models of initial state fluctuations that are tuned to describe the participant plane anisotropies. The differences can be interpreted as a decorrelation of the neutron spectator plane and the reaction plane because of fragmentation of the remnants from the colliding nuclei, which points to an incompleteness of current models describing the initial state fluctuations. A significant transverse momentum dependence of the ratio v2{ SP}/v2{4} is observed in all but the most central collisions, which may help to understand whether momentum anisotropies at low and intermediate transverse momentum have a common origin in initial state f luctuations. The ratios of v2{ SP} and v2{4} to the corresponding initial state eccentricities for Xe–Xe and Pb–Pb collisions at similar initial entropy density show a difference of (7.0 ±0.9)%with an additional variation of +1.8% when including RHIC data in the TRENTo parameter extraction. These observations provide new experimental constraints for viscous effects in the hydrodynamic modeling of the expanding quark–gluon plasma produced in heavy-ion collisions at the LHC

Microwave Propagation in Rectangular Waveguide Containing a Semiconductor Subject to a Transverse Magnetic Field

The propagation constant of waveguide partially loaded with a semiconductor in the H plane is evaluated using a three-mode approximation analysis. As the waveguide is progressively filled, a large peak occurs in the attenuation coefficient due to higher order mode propagation. In the presence of a transverse magnetic field, propagation becomes nonreciprocal and this nonreciprocal effect is shown to be significantly increased in the region of the peak. The theoretical results are verified using n-type germanium samples in 26.5-40-GHz waveguide. Copyrigh

Air-Gap Effect in Rectangular Waveguide Containing a Lossy H-Plane Dielectric Slab

The propagation coefficient for a partially filled rectangular waveguide containing a lossy H-plane slab against the broad wall can be significantly altered if an air gap exists between the slab and the wall of the waveguide. The solution of the dispersion equation show that the attenuation and phase coefficients may be increased aswell as decreased by the presence of an air gap. For a filled waveguide the effect of an air gap is maximized if the gap is equally distributed at the top and bottom of the sample. Copyrigh

Are two views better than one? Investigating three-quarter view facial composites

Purpose – The introduction of a three-quarter-view database in the PRO-fit facial-composite system has enabled an investigation into the effects of image view in face construction. The article examines the impact of constructing full-face and three-quarter-view composites under different encoding conditions. It also examines the potential value of three-quarter-view composites that can be generated automatically from a front-view composite. We also investigate whether there is an identification benefit for presenting full-face and three-quarter composites together. Design/methodology/approach – Three experiments examine the impact of encoding conditions on composite construction and presentation of composites at the evaluation stage. Findings – The work revealed that while standard full-face composites perform well when all views of the face have been encoded, care should be taken when a person has only seen one view. When a witness has seen a side view of a suspect, a three-quarter-view composite should be constructed. Also, it would be beneficial for a witness to construct two composites of a suspect, one in full-face view and one in a three-quarter-view, particularly when the witness has only encoded one view. No benefit emerged for use of three-quarter-view composites generated automatically. Research limitations/implications – This is the first study to examine viewpoint in facial composite construction. While a great deal of research has examined viewpoint dependency in face recognition tasks, composite construction is a reconstruction task involving both recall and recognition. The results indicate that there is a viewpoint effect that is similar to that described in the recognition literature. However, more research is needed in this area. Practical implications – The practical implications of this research are that it is extremely important for facial composite operators in the field (police operators) to know who will make a good likeness of the target. Research such as this which examines real-life issues is incredibly important. This research shows that if a witness has seen all views of a perpetrator’s face then standard composite construction using a full-face view will work well. However, if they have only seen a single view then it will not. Social implications – There are obvious wider societal implications for any research which deals with eyewitness memory and the potential identification of perpetrators. Originality/value – No research to date has formally examined the impact of viewpoint in facial-composite construction