Primordial Nucleosynthesis for the New Cosmology: Determining Uncertainties and Examining Concordance

Big bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) have a long history together in the standard cosmology. The general concordance between the predicted and observed light element abundances provides a direct probe of the universal baryon density. Recent CMB anisotropy measurements, particularly the observations performed by the WMAP satellite, examine this concordance by independently measuring the cosmic baryon density. Key to this test of concordance is a quantitative understanding of the uncertainties in the BBN light element abundance predictions. These uncertainties are dominated by systematic errors in nuclear cross sections. We critically analyze the cross section data, producing representations that describe this data and its uncertainties, taking into account the correlations among data, and explicitly treating the systematic errors between data sets. Using these updated nuclear inputs, we compute the new BBN abundance predictions, and quantitatively examine their concordance with observations. Depending on what deuterium observations are adopted, one gets the following constraints on the baryon density: OmegaBh^2=0.0229\pm0.0013 or OmegaBh^2 = 0.0216^{+0.0020}_{-0.0021} at 68% confidence, fixing N_{\nu,eff}=3.0. Concerns over systematics in helium and lithium observations limit the confidence constraints based on this data provide. With new nuclear cross section data, light element abundance observations and the ever increasing resolution of the CMB anisotropy, tighter constraints can be placed on nuclear and particle astrophysics. ABRIDGEDComment: 54 pages, 20 figures, 5 tables v2: reflects PRD version minor changes to text and reference

PARITY VIOLATION EFFECTS IN RESONANCE NEUTRON CROSS SECTIONS

On a observé la violation de la parité dans les résonances neutroniques des noyaux non fissiles. Les résultats de nos expériences sont en bon accord avec les données pour des neutrons thermiques et avec les prévisions théoriques.Parity nonconservation in neutron resonances of nonfissible nuclei is observed. The experimental results are in agreement with the parity nonconserving effects in thermal neutron cross sections and with the theoretical predictions

Experimental study of the plastic scintillator damage caused by radiation on IREN at JINR.

This paper describes the studies of four types of plastic scintillators SCSN-81, UPS-923A (made by KIPT, Kharkov), BC-408, LHE (made by JINR, Dubna) performed by the CMS JINR group on Intense Resonance Neutron source (IREN) - the JINR neutron source facility. These studies were performed to measure a light yield from samples of different shapes before and after irradiation. The investigation was performed to understand the dependence of light yield on the dose rate

Measuring of induced radioactivity of the HE megatile on IREN at JINR.

Results of measurement of the induced radioactivity caused by neutrons for a segment of a multi sectional scintillation detector (megatile) are presented. Two endcap sampling calorimeters (HE) are parts of the hadron calorimeter (HCAL) of experimental setup CMS. Each HE consists of 648 megatiles. Irradiation of a section of the megatile by neutrons has been performed as neutron activation is the main source of induced radioactivity. Irradiation of a segment of the megatile was carried out on IREN - the JINR neutron source facility. The HE will be accessible to humans after a suitable period of cool down