Monte Carlo study of particle production in diffractive proton-proton collisions at s\sqrt s = 13 TeV with the very forward detector combined with central information

Very forward (VF) detectors in hadron colliders, having unique sensitivity to diffractive processes, can be a powerful tool for studying diffractive dissociation by combining them with central detectors. Several Monte Carlo simulation samples in $p$-$p$ collisions at $\sqrt s = 13$ TeV were analyzed, and different nondiffractive and diffractive contributions were clarified through differential cross sections of forward neutral particles. Diffraction selection criteria in the VF-triggered-event samples were determined by using the central track information. The corresponding selection applicable in real experiments has $\approx$100% purity and 30%-70% efficiency. Consequently, the central information enables classification of the forward productions into diffraction and nondiffraction categories; in particular, most of the surviving events from the selection belong to low-mass diffraction events at $\log_{10}(\xi_{x}) < -5.5$. Therefore, the combined method can uniquely access the low-mass diffraction regime experimentally.Comment: 10 pages, 16 figures, 1table

Origin of the Temperature Oscillation in Turbulent Thermal Convection

We report an experimental study of the three-dimensional spatial structure of the low frequency temperature oscillations in a cylindrical Rayleigh-B\'{e}nard convection cell. It is found that thermal plumes are not emitted periodically, but randomly and continuously, from the top and bottom plates. We further found that the oscillation of the temperature field does not originate from the boundary layers, but rather is a result of the horizontal motion of the hot ascending and cold descending fluids being modulated by the twisting and sloshing motion of the bulk flow field.Comment: 5 figure

The metaphoric nature of the ordinal position effect

Serial orders are thought to be spatially represented in working memory: The beginning items in the memorised sequence are associated with the left side of space and the ending items are associated with the right side of space. However, the origin of this ordinal position effect has remained unclear. It was suggested that the direction of serial order–space interaction is related to the reading/writing experience. An alternative hypothesis is that it originates from the “more is right”/“more is up” spatial metaphors we use in daily life. We can adjudicate between the two viewpoints in Chinese readers; they read left-to-right but also have a culturally ancient top-to-bottom reading/writing direction. Thus, the reading/writing viewpoint predicts no or a top-to-bottom effect in serial order–space interaction; whereas the spatial metaphor theory predicts a clear bottom-to-top effect. We designed four experiments to investigate this issue. First, we found a left-to-right ordinal position effect, replicating results obtained in Western populations. However, the vertical ordinal position effect was in the bottom-to-top direction; moreover, it was modulated by hand position (e.g., left hand bottom or up). We suggest that order–space interactions may originate from different sources and are driven by metaphoric comprehension, which itself may ground cognitive processing