The Distribution of Constituent Charm Quarks in the Hadron

Using a statistical approach in the framework of non-covariant perturbation theory the distributions for light and charmed quarks in the hadron have been derived, taking into account the mass of the charmed quark. The parameters of the model have been extracted from the comparison with NA3 data on hadroproduction of J/psi particles. A reanalysis of the EMC data on charm production in muon-nucleon scattering has been performed. It has been found in comparison with the conventional source of charmed quarks from photon-gluon fusion, that the EMC data indicate the presence of an additional contribution from deep-inelastic scattering on charmed quarks at large x. The resulting admixture of the Fock states, containing charmed quarks in the decomposition of the proton wave function is of the order of 1%. The approach presented for the excitation of the Fock states with charmed quarks can also be applied to states with beauty quarks as well as to the hadronic component of the virtual photon (resolved photon component).Comment: 23 pages, 4 PostScript figures, Latex2e. In revised version in comparison with the original one all (?) mistypings have been corrected, one more thank has been added and the comparison of the pion and the proton J/psi production is described in more detai

Multiple Interactions and the Structure of Beam Remnants

Recent experimental data have established some of the basic features of multiple interactions in hadron-hadron collisions. The emphasis is therefore now shifting, to one of exploring more detailed aspects. Starting from a brief review of the current situation, a next-generation model is developed, wherein a detailed account is given of correlated flavour, colour, longitudinal and transverse momentum distributions, encompassing both the partons initiating perturbative interactions and the partons left in the beam remnants. Some of the main features are illustrated for the Tevatron and the LHC.Comment: 69pp, 33 figure

Transverse Spin Structure of the Nucleon through Target Single Spin Asymmetry in Semi-Inclusive Deep-Inelastic (e,e′π±)(e,e^\prime \pi^\pm) Reaction at Jefferson Lab

Jefferson Lab (JLab) 12 GeV energy upgrade provides a golden opportunity to perform precision studies of the transverse spin and transverse-momentum-dependent structure in the valence quark region for both the proton and the neutron. In this paper, we focus our discussion on a recently approved experiment on the neutron as an example of the precision studies planned at JLab. The new experiment will perform precision measurements of target Single Spin Asymmetries (SSA) from semi-inclusive electro-production of charged pions from a 40-cm long transversely polarized $^3$He target in Deep-Inelastic-Scattering kinematics using 11 and 8.8 GeV electron beams. This new coincidence experiment in Hall A will employ a newly proposed solenoid spectrometer (SoLID). The large acceptance spectrometer and the high polarized luminosity will provide precise 4-D ($x$, $z$, $P_T$ and $Q^2$) data on the Collins, Sivers, and pretzelocity asymmetries for the neutron through the azimuthal angular dependence. The full 2$\pi$ azimuthal angular coverage in the lab is essential in controlling the systematic uncertainties. The results from this experiment, when combined with the proton Collins asymmetry measurement and the Collins fragmentation function determined from the e$^+$e$^-$ collision data, will allow for a quark flavor separation in order to achieve a determination of the tensor charge of the d quark to a 10% accuracy. The extracted Sivers and pretzelocity asymmetries will provide important information to understand the correlations between the quark orbital angular momentum and the nucleon spin and between the quark spin and nucleon spin.Comment: 23 pages, 13 figures, minor corrections, matches published versio

Determination of the gluon polarization at RHIC and COMPASS

The most recent determinations of the gluon polarization in the nucleon, ${\frac{{\Delta G}}{{G}}}$ , obtained at RHIC and COMPASS experiments, are reviewed. The former accesses the gluon polarization mainly through the production of neutral pions (PHENIX) or jets (STAR) in polarized proton collisions. The latter uses the photon-gluon fusion in polarized lepton-nucleon scattering, tagged either by open charm or high-pT hadrons production. All the results are in good agreement, and favour values of ΔG roughly between 0 and 0.5 at a few (GeV/c)2 , thus in contradiction with what could be derived from the Ellis-Jaffe sum rule and the axial anomaly. Much stronger constraints will be obtained in a near future by both programs, helping us to clarify the role of gluons in the nucleon spin

Dataset for "Interactions of Choline and Geranate (CAGE) and Choline Octanoate (CAOT) Deep Eutectic Solvents with Lipid Bilayers"

Deep eutectic solvents (DES) and ionic liquids (ILs) are often amphiphilic and interact with phospholipid membranes. Mixtures between choline and gernanic acid, coined 'CAGE', have been found to facilitate the transdermal delivery of larger pharmaceuticals, such as insulin. However, little is known about its mechanism of activity. The purpose for obtaining this data was to characterise aqueous suspensions of choline and germanic acid (CAGE) and choline and octanoic acid (CAOT) and compare their interactions with solid-supported lipid bilayers and vesicle layers. Particularly, dynamic light scattering (DLS) and quartz crystal microbalance with dissipation (QCM-D) measurements were used alongside neutron reflectivity (NR) to evaluate any structure-function relationships contributing to the DES behaviour, aiming towards the rational design of neoteric solvents for transdermal delivery