Nuclear effects in Deep Inelastic Scattering of polarized electrons off polarized 3He and the neutron spin structure functions

It is shown that the nuclear effects playing a relevant role in Deep Inelastic Scattering of polarized electrons by polarized $^3$He are mainly those arising from the effective proton and neutron polarizations generated by the $S'$ and $D$ waves in $^3$He. A simple and reliable equation relating the neutron, $g_1^n$, and $^3$He, $g_1^3$, spin structure functions is proposed. It is shown that the measurement of the first moment of the $^3$He structure function can provide a significant check of the Bjorken Sum Rule.Comment: 11 pages (revTeX), DFUPG 75/93; 5 (postscript) figures available upon request from the author

Freezing Transition in Decaying Burgers Turbulence and Random Matrix Dualities

We reveal a phase transition with decreasing viscosity $\nu$ at \nu=\nu_c>0 in one-dimensional decaying Burgers turbulence with a power-law correlated random profile of Gaussian-distributed initial velocities \sim|x-x'|^{-2}. The low-viscosity phase exhibits non-Gaussian one-point probability density of velocities, continuously dependent on \nu, reflecting a spontaneous one step replica symmetry breaking (RSB) in the associated statistical mechanics problem. We obtain the low orders cumulants analytically. Our results, which are checked numerically, are based on combining insights in the mechanism of the freezing transition in random logarithmic potentials with an extension of duality relations discovered recently in Random Matrix Theory. They are essentially non mean-field in nature as also demonstrated by the shock size distribution computed numerically and different from the short range correlated Kida model, itself well described by a mean field one step RSB ansatz. We also provide some insights for the finite viscosity behaviour of velocities in the latter model.Comment: Published version, essentially restructured & misprints corrected. 6 pages, 5 figure

Finite elements and the discrete variable representation in nonequilibrium Green's function calculations. Atomic and molecular models

In this contribution, we discuss the finite-element discrete variable representation (FE-DVR) of the nonequilibrium Green's function and its implications on the description of strongly inhomogeneous quantum systems. In detail, we show that the complementary features of FEs and the DVR allows for a notably more efficient solution of the two-time Schwinger/Keldysh/Kadanoff-Baym equations compared to a general basis approach. Particularly, the use of the FE-DVR leads to an essential speedup in computing the self-energies. As atomic and molecular examples we consider the He atom and the linear version of H$_3^+$ in one spatial dimension. For these closed-shell models we, in Hartree-Fock and second Born approximation, compute the ground-state properties and compare with the exact findings obtained from the solution of the few-particle time-dependent Schr\"odinger equation.Comment: 12 pages, 3 figures, submitted as proceedings of conference "PNGF IV

Random close packing of polydisperse hard spheres

We study jammed configurations of hard spheres as a function of compression speed using an event-driven molecular dynamics algorithm. We find that during the compression, the pressure follows closely the metastable liquid branch until the system gets arrested into a glass state as the relaxation time exceeds the compression speed. Further compression yields a jammed configuration that can be regarded as the infinite pressure configuration of that glass state. Consequently, we find that the density of jammed packings varies from 0.638 to 0.658 for polydisperse hard spheres and from 0.635 to 0.645 for pure hard spheres upon decreasing the compression rate. This demonstrates that the density at which the systems falls out of equilibrium determines the density at which the system jams at infinite pressure. In addition, we give accurate data for the jamming density as a function of compression rate and size polydispersity.Comment: Four pages, three figure

On cosmologically induced hierarchies in string theory

We propose, within a perturbative string theory example, a cosmological way to generate a large hierarchy between the observed Planck mass and the fundamental string scale. Time evolution results in three large space dimensions, one additional dimension transverse to our world and five small internal dimensions with a very slow time evolution. The evolution of the string coupling and internal space generate a large Planck mass. However due to an exact compensation between the time evolution of the internal space and that of the string coupling, the gauge and Yukawa couplings on our Universe are time independent.Comment: 12 pages, LaTeX, interpretation of the solution clarified, typos corrected, references adde

Constraints on braneworld inflation from CMB anisotropies

We obtain observational constraints on Randall--Sundrum type II braneworld inflation using a compilation of data including WMAP, the 2dF and latest SDSS galaxy redshift surveys. We place constraints on three classes of inflation models (large-field, small-field and hybrid models) in the high-energy regime, which exhibit different behaviour compared to the low-energy case. The quartic potential is outside the $2\sigma$ observational contour bound for a number of $e$-folds less than 60, and steep inflation driven by an exponential potential is excluded because of its high tensor-to-scalar ratio. It is more difficult to strongly constrain small-field and hybrid models due to additional freedoms associated with the potentials, but we obtain upper bounds for the energy scale of inflation and the model parameters in certain cases. We also discuss possible ways to break the degeneracy of consistency relations and inflationary observables.Comment: 12 pages, 7 figure

Charged-particle nuclear modification factors in PbPb and pPb collisions at √sNN=5.02 TeV

The spectra of charged particles produced within the pseudorapidity window |η| 20 GeV, RpA exhibits weak momentum dependence and shows a moderate enhancement above unity

Search for heavy Majorana neutrinos in e+-e+-+ jets and e+-μ+-+ jets events in proton-proton collisions at s = 8 s√=8 TeV

A search is performed for heavy Majorana neutrinos (N) decaying into a W boson and a lepton using the CMS detector at the Large Hadron Collider. A signature of two jets and either two same sign electrons or a same sign electron-muon pair is searched for using 19.7 fb−1 of data collected during 2012 in proton-proton collisions at a centre-of-mass energy of 8 TeV. The data are found to be consistent with the expected standard model (SM) background and, in the context of a Type-1 seesaw mechanism, upper limits are set on the cross section times branching fraction for production of heavy Majorana neutrinos in the mass range between 40 and 500 GeV. The results are additionally interpreted as limits on the mixing between the heavy Majorana neutrinos and the SM neutrinos. In the mass range considered, the upper limits range between 0.00015–0.72 for |VeN|2 and 6.6 × 10−5−0.47 for |VeNVμN∗|2/(|VeN|2 + |VμN|2), where VℓN is the mixing element describing the mixing of the heavy neutrino with the SM neutrino of flavour ℓ. These limits are the most restrictive direct limits for heavy Majorana neutrino masses above 200 GeV