Predictions for double spin asymmetry A_{LT} in Semi Inclusive DIS

In the leading order of QCD parton model of Semi Inclusive Deep Inelastic Scattering (SIDIS) the double spin asymmetry $A_{LT}$ arises due to the longitudinal polarization of quarks in the transversely polarized nucleon. The corresponding $k_T^2$ weighted distribution function $g^{(1)}_{1T}$ can be related to ordinary helicity distribution $g_1(x)$ measured in DIS. Using recent parameterizations for (un)polarized distribution and fragmentation functions we calculated $A_{LT}$ asymmetry on transversely polarized proton and deuteron targets for different types hadron production. The predictions are given for COMPASS, HERMES and JLab energies. The role of Lorentz invariance relations and positivity constraints are discussed.Comment: The new conventional definition of asymmetry is adopted -- the factor two is added. The figures are rescaled by factor tw

The evolved circumbinary disk of AC Her: a radiative transfer, interferometric and mineralogical study

We aim to constrain the structure of the circumstellar material around the post-AGB binary and RV Tauri pulsator AC Her. We want to constrain the spatial distribution of the amorphous as well as of the crystalline dust. We present very high-quality mid-IR interferometric data that were obtained with MIDI/VLTI. We analyse the MIDI data and the full SED, using the MCMax radiative transfer code, to find a good structure model of AC Her's circumbinary disk. We include a grain size distribution and midplane settling of dust self-consistently. The spatial distribution of crystalline forsterite in the disk is investigated with the mid-IR features, the 69~$\mu$m band and the 11.3~$\mu$m signatures in the interferometric data. All the data are well fitted. The inclination and position angle of the disk are well determined at i=50+-8 and PA=305+-10. We firmly establish that the inner disk radius is about an order of magnitude larger than the dust sublimation radius. Significant grain growth has occurred, with mm-sized grains being settled to the midplane of the disk. A large dust mass is needed to fit the sub-mm fluxes. By assuming {\alpha}=0.01, a good fit is obtained with a small grain size power law index of 3.25, combined with a small gas/dust ratio <10. The resulting gas mass is compatible with recent estimates employing direct gas diagnostics. The spatial distribution of the forsterite is different from the amorphous dust, as more warm forsterite is needed in the surface layers of the inner disk. The disk in AC Her is very evolved, with its small gas/dust ratio and large inner hole. Mid-IR interferometry offers unique constraints, complementary to mid-IR features, for studying the mineralogy in disks. A better uv coverage is needed to constrain in detail the distribution of the crystalline forsterite in AC Her, but we find strong similarities with the protoplanetary disk HD100546.Comment: update with final version published in A&

Mass and width of the d′d' resonance in nuclei

We calculated the mass and width of the $d'$ resonance inside nuclei within a nucleon-$\Delta$ model by including the self-energy of the $\Delta$ in the $N\Delta$ propagator. We found that in the nuclear medium the width of the $d'$ is increased by one order of magnitude while its mass changes only by a few MeV. This broadening of the width of the $d'$ resonance embedded in nuclei is consistent with the experimental observations so that the $d'$ can be understood as a $N\Delta$ resonance. Thus, given the freedom between either isospin 0 or isospin 2 for the $d'$, our results give weigth to the isospin-2 assignment.Comment: 14 pages, RevteX type, 2 eps figures. To be published in Phys. Rev. C (September

Bounds on transverse momentum dependent distribution and fragmentation functions

We give bounds on the distribution and fragmentation functions that appear at leading order in deep inelastic 1-particle inclusive leptoproduction or in Drell-Yan processes. These bounds simply follow from positivity of the defining matrix elements and are an important guidance in estimating the magnitude of the azimuthal and spin asymmetries in these processes.Comment: 5 pages, Revtex, 3 Postscript figures, version with minor changes, to be published in Physical Review Letter

A polarized version of the CCFM equation for gluons

A derivation for a polarized CCFM evolution equation which is suitable to describe the scaling behavior of the the unintegrated polarized gluon density is given. We discuss the properties of this polarized CCFM equation and compare it to the standard CCFM equation in the unpolarized case.Comment: 15 pages, 6 figures, RevTeX, some minor typos corrected, version to appear in Phys. Rev.

Search for Narrow NNpi Resonances in Exclusive p p -> p p pi+ pi- Measurements

Narrow structures in the range of a few MeV have been searched for in p p pi+ and p p pi- invariant mass spectra obtained from exclusive measurements of the p p -> p p pi+ pi- reaction at Tp = 725, 750 and 775 MeV using the PROMICE/WASA detector at CELSIUS. The selected reaction is particularily well suited for the search for NN and / or N Delta decoupled dibaryon resonances. Except for a possible fluctuation at 2087 MeV/c^2 in Mpppi- no narrow structures could be identified neither in Mpppi+ nor in Mpppi- on the 3 sigma level of statistical significance, giving an upper limit (95% C.L.) for dibaryon production in this reaction of sigma < 20 nb for 2020 MeV/c^2 < m(dibaryon) < 2085 MeV/c^2Comment: 3 pages, 4 figure

Compressed Silica Aerogels for the Study of Superfluid 3He

We have performed Small Angle X-ray Scattering (SAXS) on uniaxially strained aerogels and measured the strain-induced structural anisotropy. We use a model to connect our SAXS results to anisotropy of the 3He quasiparticle mean free path in aerogel.Comment: 2 pages, 2 figures, accepted for publication in the proceedings of the 24th Low Temperature Physics Conferenc

Torsional oscillator and synchrotron x-ray experiments on solid 4He in aerogel

X-ray diffraction experiments show that solid 4He grown in aerogel is highly polycrystalline, with a hcp crystal structure (as in bulk) and a crystallite size of approximately 100 nm. In contrast to the expectation that the highly disordered solid will have a large supersolid fraction, torsional oscillator measurements show a behavior that is strikingly similar to high purity crystals grown from the superfluid phase. The low temperature supersolid fraction is only ~3x10-4 and the onset temperature is ~ 100 mK

Measurement of the CMS Magnetic Field

The measurement of the magnetic field in the tracking volume inside the superconducting coil of the Compact Muon Solenoid (CMS) detector under construction at CERN is done with a fieldmapper designed and produced at Fermilab. The fieldmapper uses 10 3-D B-sensors (Hall probes) developed at NIKHEF and calibrated at CERN to precision 0.05% for a nominal 4 T field. The precise fieldmapper measurements are done in 33840 points inside a cylinder of 1.724 m radius and 7 m long at central fields of 2, 3, 3.5, 3.8, and 4 T. Three components of the magnetic flux density at the CMS coil maximum excitation and the remanent fields on the steel-air interface after discharge of the coil are measured in check-points with 95 3-D B-sensors located near the magnetic flux return yoke elements. Voltages induced in 22 flux-loops made of 405-turn installed on selected segments of the yoke are sampled online during the entire fast discharge (190 s time-constant) of the CMS coil and integrated offline to provide a measurement of the initial magnetic flux density in steel at the maximum field to an accuracy of a few percent. The results of the measurements made at 4 T are reported and compared with a three-dimensional model of the CMS magnet system calculated with TOSCA.Comment: 4 pages, 5 figures, 15 reference

Universal Behaviour of the Superfluid Fraction and Tc of He-3 in 99.5% Open Aerogel

We have investigated the superfluid transition of He-3 in a 99.5% porosity silica aerogel. This very dilute sample shows behaviour intermediary between bulk He-3 and He-3 confined to the denser aerogels previously studied. We present data on both the superfluid transition temperature and the superfluid density and compare our results with previous measurements. Finally, we show that the suppression of the superfluid transition temperature and suppression of the superfluid density of He-3 in aerogel follow a universal relation for a range of aerogel samples.Comment: 4 pages, 5 figures; 1 new figure, minor change