Azimuthal single- and double-spin asymmetries in semi-inclusive deep-inelastic lepton scattering by transversely polarized protons

A comprehensive set of azimuthal single-spin and double-spin asymmetries in semi-inclusive leptoproduction of pions, charged kaons, protons, and antiprotons from transversely polarized protons is presented. These asymmetries include the previously published HERMES results on Collins and Sivers asymmetries, the analysis of which has been extended to include protons and antiprotons and also to an extraction in a three-dimensional kinematic binning and enlarged phase space. They are complemented by corresponding results for the remaining four single-spin and four double-spin asymmetries allowed in the one-photon-exchange approximation of the semi-inclusive deep-inelastic scattering process for target-polarization orientation perpendicular to the direction of the incoming lepton beam. Among those results, significant non-vanishing cos (phi-phi(S)) modulations provide evidence for a sizable worm-gear (II) distribution, g(1T)(q) (x, p(T)(2)). Most of the other modulations are found to be consistent with zero with the notable exception of large sin (phi(S)) modulations for charged pions and K+

HERMES - ein neues HERA-Experiment zur Klärung des Spinrätsels

In 1987, the spin distribution of the quarks in the proton was determined by the European Myon Collaboration (EMC) at CERN [1]. The results were in contradiction with the current ideas and predictions and surprised the professional world so much that a spin crisis "of the Quark-Parton model was spoken [2]. In the last eight years, there have been great advances both in the theoretical understanding of the spin distributions of the quarks in the QCD and in the experimental field by new experiments at CERN and the SLAC. Nevertheless, there are still more open questions than answers. The HERMES experiment at the HERA storage ring at DESY [3] is an entirely new type of experiment. His goal is to provide comprehensive and precise insights into the internal spin structure of Proton and Neutron using novel technologies

DVCS and associated processes at HERMES

Deeply virtual Compton scattering provides information about the structure of nucleon in the framework of generalized parton distributions. During the last 13 years, DVCS was extensively studied at the HERMES experiment through measurement of various cross-section asymmetries. Due to unique experimental conditions, HERMES has collected a wealth of data on scattering polarized electron and positron beams off unpolarized and longitudinally polarized hydrogen and deuterium targets, as well as off transversely polarized hydrogen targets. The variety of measured asymmetries provides sensitivity to real and/or imaginary parts of different combination of Compton form factors, and thus related GPDs. The HERMES recoil detector is used to separate pure DVCS from associated DVCS processes involving resonance production

The influence of duration, arm crossing style, gender, and emotional closeness on hugging behaviour

Hugging is one of the most common types of affective touch encountered in everyday life. However, little is known about the factors that influence hugging evaluation and behaviour. Here, we aimed to assess how different hugs would be evaluated and whether they can affect mood. Furthermore, we aimed to investigate what kind of arm crossing is common in a naturalistic setting and whether arm crossing style could be predicted from gender, emotional closeness, and the height difference of huggers. We conducted two studies addressing these questions. In study 1, participants hugged a confederate for 1 second (s), 5 s or 10 s with two different arm crossing styles and reported how pleasant, arousing and under control the touch felt. Additionally, participants were asked about their mood (“self-ratings”) immediately after, 3 minutes (min) after and 6 min after each hug. In study 2, participants were approached on campus and asked to share a hug, with arm crossing style being the dependent variable. The height difference, gender and self-rated emotional closeness to the hug partner were recorded as possible predictors for arm crossing style. Results from study 1 indicate that duration matters more than arm crossing style for hug pleasure, arousal, and control, with 1 s hugs being rated as least pleasant and under control than 5 s and 10 s hugs. Accordingly, 1 s hugs also resulted in lower pleasure self-ratings immediately post hug than 5 s and 10 s hugs. Arousal self-ratings were higher immediately post hug than several minutes after a hug. In study 2, gender was linked to arm crossing style, with male-male hug dyads exhibiting a different hugging style from female-female dyads. These findings are discussed in relation to previous hug research and gender differences in touch behaviour

Perspectives on interpersonal touch are related to subjective sleep quality

Affective touch has been reported for its calming effects; however, it is less clear whether touch is associated with sleep. Here, the relationship between different touch variables and self-reported sleep indicators was investigated. Data were extracted from the Touch Test, a cross-sectional survey conducted in 2020. Data from a sample of 15049 healthy adults from the UK (mean age = 56.13, SD = 13.8; 75.4% female) were analysed. Participants were asked to attribute positive, negative or no effects on sleep to hugs, strokes, massages, intimate touch, and sleep onset with and without touch. The time since last intentional touch, touch amount satisfaction, and childhood bed routine with hugs and kisses were assessed. Sleep quality, -duration, -latency, wake after sleep onset and diurnal preference were measured. Data were analysed using chi-square tests and logistic regressions. Affective touch before sleep was perceived to have positive effects on sleep. Touch recency emerged as a significant predictor for some sleep variables, with a longer timespan since last intentional touch relating to improved sleep quality, longer sleep duration, and shorter and fewer instances of waking up after sleep onset in some participants. Experiencing too much touch was related to lower sleep quality and higher instances of waking up after sleep onset. These findings highlight the importance of interpersonal touch for subjective sleep quality

Associations between tactile intimacy and sleep quality in healthy adults: a systematic review

Prior research suggests that different types of touch can affect sleep, but whether there is a consistent association between tactile intimacy and sleep quality is unclear. Here, we report a pre-registered systematic review (International Prospective Register of Systematic Reviews [PROSPERO], CRD42020158683) of studies examining the association between tactile intimacy and sleep quality in healthy adults. The databases PsycINFO, PubMed, Web of Science, the Cochrane Central Register of Controlled Trials and EMBASE were searched on August 7, 2020. A total of 13 studies met the inclusion criteria and were synthesised qualitatively. Most commonly, articles researched sexual intimacy in relation to sleep quality, but some studies also investigated non-sexual affective touch and emotionally neutral touch. Some evidence for a connection between sexual function, sexual satisfaction and masturbation with sleep quality was found; however, no evidence for an association between sexual frequency or sexual positions and sleep was found. Interestingly, studies employing more subjective approaches were more likely to report an association between touch and sleep, potentially highlighting a discrepancy between self-reported and the objectively measurable association between touch and sleep

Flexibility and swing effect on the adsorption of energy-related gases on ZIF-8: combined experimental and simulation study

ZIF-8, a prototypical zeolitic porous coordination polymer, prepared via the self-assembly of tetrahedral atoms (e.g. Zn and Co) and organic imidazolate linkers, presents large cavities which are interconnected by narrow windows that allow, in principle, molecular sieving. However, ZIF-8 shows flexibility due to the swing of the imidazolate linkers, which results in the adsorption of molecules which are too large to fit through the narrow window. In this work, we assess the impact of this flexibility, previously only observed for nitrogen, and the level of agreement between the experimental and simulated isotherms of different energy-related gases on ZIF-8 (CO2, CH4 and alkanes). We combine experimental gas adsorption with GCMC simulations, using generic and adjusted force fields and DFT calculations with the Grimme dispersion correction. By solely adapting the UFF force field to reduce the Lennard-Jones parameter e, we achieve excellent agreement between the simulated and experimental results not only for ZIF-8 but also for ZIF-20, where the transferability of the adapted force field is successfully tested. Regarding ZIF-8, we show that two different structural configurations are needed to properly describe the adsorption performance of this material, demonstrating that ZIF-8 is undergoing a structural change during gas adsorption. DFT calculations with the Grimme dispersion correction are consistent with the GCMC and experimental observations, illustrating the thermodynamics of the CH4 adsorption sites and confirming the existence of a new adsorption site with a high binding energy within the 4-ring window of ZIF-8.</p