Impact of Uncertainties in Hadron Production on Air-Shower Predictions

At high energy, cosmic rays can only be studied by measuring the extensive air showers they produce in the atmosphere of the Earth. Although the main features of air showers can be understood within a simple model of successive interactions, detailed simulations and a realistic description of particle production are needed to calculate observables relevant to air shower experiments. Currently hadronic interaction models are the main source of uncertainty of such simulations. We will study the effect of using different hadronic models available in CORSIKA and CONEX on extensive air shower predictions.Comment: 12 pages, 6 figures, to appear in the proceedings of International Conference on Interconnection between High Energy Physics and Astroparticle Physics: From Colliders to Cosmic Rays, Prague, Czech Republic, 7-13 Sep 200

Native chick laminin-4 containing the beta 2 chain (s-laminin) promotes motor axon growth.

After denervation of muscle, motor axons reinnervate original synaptic sites. A recombinant fragment of the synapse specific laminin beta 2 chain (s-laminin) was reported to inhibit motor axon growth. Consequently, a specific sequence (leucine-arginine-glutamate, LRE) of the laminin beta 2 chain was proposed to act as a stop signal and to mediate specific reinnervation at the neuromuscular junction (Porter, B.E., J. Weis, and J.R. Sanes. 1995. Neuron. 14:549-559). We demonstrate here that native chick laminin-4, which contains the beta 2 chain and is present in the synaptic basement membrane, does not inhibit but rather promotes motor axon growth. In native heterotrimeric laminin, the LRE sequence of the beta 2 chain is found in a triple coiled-coil region that is formed by all three subunits. We show here that the effect of LRE depends on the structural context. Whereas a recombinant randomly coiled LRE peptide indeed inhibited outgrowth by chick motoneurons, a small recombinant triple coiled-coil protein containing this sequence did not

d-Au and p-p collisions at RHIC and the multichain Monte Carlo Dpmjet-III

In this paper we compare systematically the two-component Dual Parton Model (DPM) event generator Dpmjet-III to d-Au and p-p data from RHIC. In this process we are able to improve the model. The need for fusion of chains and a recalibration of the model to obtain collision scaling in h-A and d-A collisions was found already in previous comparisons. Here, comparing to transverse momentum distributions of identified charged hadrons we find also the need to modify the transverse momentum distributions in the decay of hadronic strings, the basic building blocks of the model on soft hadronic collisions.Comment: 8 pages, 13 figures, Based on a contribution to a workshop "QCD at Cosmic Energies, Erice, Italie, Aug.29 to Sept.5 200

Antibaryon to Baryon Production Ratios in Pb-Pb and p-p collision at LHC energies of the DPMJET-III Monte Carlo

A sizable component of stopped baryons is predicted for pp and P bP b collisions at LHC. Based on an analysis of RHIC data within framework of our multichain Monte Carlo DPMJET-III the LHC predictions are presented.Comment: Presented at "Heavy Ion Collisions at the LHC: last call for predictions", Geneva Switzerland, May 14th-June 8t