Nuclear corrections in neutrino-nucleus DIS and their compatibility with global NPDF analyses

We perform a global chi^2-analysis of nuclear parton distribution functions using data from charged current neutrino-nucleus deep-inelastic scattering (DIS), charged-lepton-nucleus DIS, and the Drell-Yan (DY) process. We show that the nuclear corrections in nu-A DIS are not compatible with the predictions derived from l^+A DIS and DY data. We quantify this result using a hypothesis-testing criterion based on the chi^2 distribution which we apply to the total chi^2 as well as to the chi^2 of the individual data sets. We find that it is not possible to accommodate the data from nu-A and l^+A DIS by an acceptable combined fit. Our result has strong implications for the extraction of both nuclear and proton parton distribution functions using combined neutrino and charged-lepton data sets.Comment: 5 page

Parton distribution function uncertainties and nuclear corrections for the LHC

We study nuclear effects of charged current deep inelastic neutrino-iron scattering in the framework of a chi^2 analysis of parton distribution functions (PDFs). We extract a set of iron PDFs which are used to compute x_Bj-dependent and Q^2-dependent nuclear correction factors for iron structure functions which are required in global analyses of free nucleon PDFs. We compare our results with nuclear correction factors from neutrino-nucleus scattering models and correction factors for charged lepton-iron scattering. We find that, except for very high x_Bj, our correction factors differ in both shape and magnitude from the correction factors of the models and charged-lepton scattering

nCTEQ15 - Global analysis of nuclear parton distributions with uncertainties in the CTEQ framework

We present the new nCTEQ15 set of nuclear parton distribution functions with uncertainties. This fit extends the CTEQ proton PDFs to include the nuclear dependence using data on nuclei all the way up to 208^Pb. The uncertainties are determined using the Hessian method with an optimal rescaling of the eigenvectors to accurately represent the uncertainties for the chosen tolerance criteria. In addition to the Deep Inelastic Scattering (DIS) and Drell-Yan (DY) processes, we also include inclusive pion production data from RHIC to help constrain the nuclear gluon PDF. Furthermore, we investigate the correlation of the data sets with specific nPDF flavor components, and asses the impact of individual experiments. We also provide comparisons of the nCTEQ15 set with recent fits from other groups.Comment: 35 page

Compatibility of global NPDF analyses of neutrino DIS and charged-lepton DIS data

The neutrino deep inelastic scattering (DIS) data is very interesting for global analyses of proton and nuclear parton distribution functions (PDFs) since they provide crucial information on the strange quark distribution in the proton and allow for a better flavor decompositon of the PDFs. In order to use neutrino DIS data in a global analysis of proton PDFs nuclear effects need to be understood. We study these effects with the help of nuclear PDFs extracted from global analyses of charged-lepton DIS, Drell-Yan and neutrino DIS data at next-to-leading order in QCD.Comment: Contribution to the XXIst International Europhysics Conference on High Energy Physics, 21-27 July 2011, Grenoble, Franc

QCD Corrections to Toponium Production at Hadron Colliders

Toponium production at future hadron colliders is investigated. Perturbative QCD corrections to the production cross section for gluon fusion are calculated as well as the contributions from gluon-quark and quark-antiquark collisions to the total cross section. The dependence on the renormalization and factorization scales and on the choice of the parton distribution functions is explored. QCD corrections to the branching ratio of $\eta_{t}$ into $\gamma\gamma$ are included and the two-loop QCD potential is used to predict the wave function at the origin. The branching ratio of $\eta_{t}$ into $\gamma Z$, $ZZ$, $HZ$ and $WW$ is compared with the $\gamma\gamma$ channel.Comment: 16 pages (latex) 9 figures (postscript) available upon request, TTP92-3

Next-to-Leading Order QCD Corrections to Jet Cross Sections and Jet Rates in Deeply Inelastic Electron Proton Scattering

Jet cross sections in deeply inelastic scattering in the case of transverse photon exchange for the production of (1+1) and (2+1) jets are calculated in next-to-leading order QCD (here the `+1' stands for the target remnant jet, which is included in the jet definition for reasons that will become clear in the main text). The jet definition scheme is based on a modified JADE cluster algorithm. The calculation of the (2+1) jet cross section is described in detail. Results for the virtual corrections as well as for the real initial- and final state corrections are given explicitly. Numerical results are stated for jet cross sections as well as for the ratio \sigma_{\mbox{\small (2+1) jet}}/\sigma_{\mbox{\small tot}} that can be expected at E665 and HERA. Furthermore the scale ambiguity of the calculated jet cross sections is studied and different parton density parametrizations are compared.Comment: 40 pages, LBL-34147 (Latex file). (figures available by mail on request (send e-mail to [email protected]), please include your address such that it can be used as an address label

Revealing the electronic structure of a carbon nanotube carrying a supercurrent

Carbon nanotubes (CNTs) are not intrinsically superconducting but they can carry a supercurrent when connected to superconducting electrodes. This supercurrent is mainly transmitted by discrete entangled electron-hole states confined to the nanotube, called Andreev Bound States (ABS). These states are a key concept in mesoscopic superconductivity as they provide a universal description of Josephson-like effects in quantum-coherent nanostructures (e.g. molecules, nanowires, magnetic or normal metallic layers) connected to superconducting leads. We report here the first tunneling spectroscopy of individually resolved ABS, in a nanotube-superconductor device. Analyzing the evolution of the ABS spectrum with a gate voltage, we show that the ABS arise from the discrete electronic levels of the molecule and that they reveal detailed information about the energies of these levels, their relative spin orientation and the coupling to the leads. Such measurements hence constitute a powerful new spectroscopic technique capable of elucidating the electronic structure of CNT-based devices, including those with well-coupled leads. This is relevant for conventional applications (e.g. superconducting or normal transistors, SQUIDs) and quantum information processing (e.g. entangled electron pairs generation, ABS-based qubits). Finally, our device is a new type of dc-measurable SQUID

Chemical composition of nano-phases studied by anomalous small-angle X-ray scattering (ASAXS)

Anomalous small-angle X-ray scattering (ASAXS) is a technique developed in the 1980s. It offers the opportunity to go further in the investigation of nano-objects by providing chemical information besides characteristic features like size and volume fraction given by classical SAXS. ASAXS is an element-selective technique based on the anomalous variation of the scattering factor near the absorption edge of one chosen element. This technique requires a tunable wavelength of the incident beam that is available on synchrotron radiation sources. In this study, a simple approach is proposed and detailed to extract chemical information from anomalous SAXS data. To illustrate the procedure, two examples are treated by applying this data processing. The first one aims to discriminate between different possible phases in the Y- Ti-O system that may form nano-oxides in oxide-dispersion-strenghtened (ODS) steels, materials for future nuclear plants. The second one deals with the composition of nano- precipitates formed in the diffusion layer of nitrided steels. Such information is of prime importance to evaluate the maximum nitrogen that can be introduced by such a surface treatment and thus the mechanical properties that can be achieved

Inelastic Channels in WW Scattering

If the electroweak symmetry-breaking sector becomes strongly interacting at high energies, it can be probed through longitudinal $W$ scattering. We present a model with many inelastic channels in the $W_L W_L$ scattering process, corresponding to the production of heavy fermion pairs. These heavy fermions affect the elastic scattering of $W_L$'s by propagating in loops, greatly reducing the amplitudes in some charge channels. We conclude that the symmetry-breaking sector cannot be fully explored by using, for example, the $W_L^\pm W_L^\pm$ mode alone, even when no resonance is present; all $W_L W_L \to W_L W_L$ scattering modes must be measured.Comment: phyzzx, 13 pp. plus 4 figures, JHU-TIPAC-930005, MSUHEP-93/0