New magic number for neutron rich Sn isotopes

The variation of E(2+_1) of (134-140)Sn calculated with empirical SMPN interaction has striking similarity with that of experimental E(2+_1) of even-even (18-22)O and (42-48)Ca, showing clearly that N=84-88 spectra exhibit the effect of gradual filling up of \nu(2f_{7/2}) orbital which finally culminates in a new shell closure at N=90. Realistic two-body interaction CWG does not show this feature. Spin-tensor decomposition of SMPN and CWG interactions and variation of their components with valence neutron number reveals that the origin of the shell closure at 140Sn lies in the three body effects. Calculations with CWG3, which is obtained by including a simple three-body monopole term in the CWG interaction, predict decreasing E(2+_1) for (134-138)Sn and a shell closure at 140Sn.Comment: 4 pages, 5 figure

Have we seen anything beyond (N)NLO DGLAP at HERA?

The evidence from HERA for parton saturation, and other low-$x$ effects beyond the conventional DGLAP formalism, is recalled and critically reviewed in the light of new data and analyses presented at the conference.Comment: 4 pages, 5 figures, Contribution to the discussion session at Intenrational Symposium on Multiparticle Dynamics, ISMD08, Hambur

Extraction of the proton parton density functions using a NLO-QCD fit of the combined H1 and ZEUS inclusive DIS cross sections

The combined HERA-I data set, of neutral and charged current inclusive cross-sections for $e^+p$ and $e^-p$ scattering, is used as the sole input for a next-to-leading order (NLO) QCD parton distribution function (PDF) fit. The consistent treatment of systematic uncertainties in the joint data set ensures that experimental uncertainties on the PDFs can be calculated without need for an increased $\chi^2$ tolerance. This results in PDFs with greatly reduced experimental uncertainties compared to the separate analyses of the ZEUS and H1 experiments. Model uncertainties, including those arising from parametrization dependence, are also carefully considered. The resulting HERAPDFs have impressive precision compared to the global fits.Comment: 5 pages, 2 figures. Talk on behalf of H1 and ZEUS collaborations, to be published in the Proceedings of the 16th Workshop on Deep Inelastic Scattering, DIS2008, London, April 7-11th 200

HERA Collider Results

The final results on the combination of all inclusive deep-inelastic scattering cross section data from the H1 and ZEUS experiments at HERA are reviewed. The parton distribution functions (PDFs) extracted from these data (HERAPDF2.0) and from HERA data on heavy flavour production and jet production are also presented (HERAPDF2.0Jets). The use of various heavy flavour schemes is compared and the sensitivity of the data to cuts on Q2 is explored. When jet data are included in the fits, a competitive value of $\alpha_s(M_Z)=0.1184 \pm 0.0016$ is extracted at NLO, excluding scale uncertaintiesComment: Plenary talk at the XXIII International Workshop on Deep-Inelastic Scattering, 27th April-1st May 2015, Dallas, Texas. 14 pages, 18 figures. Based on the analysis of the H1 and ZEUS collaboration