Universal behavior of baryons and mesons' transverse momentum distributions in the framework of percolation of strings

In the framework of percolation of strings, we present predictions for the $R_{AA}$ and $R_{CP}$ for mesons and baryons and for $\bar{p}/\pi^{0}$ ratios at LHC energies.Comment: Presented at "Heavy Ion Collisions at the LHC: last call for predictions", Geneva Switzerland, May 14th-June 8t

Weak Liouville-Arnold Theorems & Their Implications

This paper studies the existence of invariant smooth Lagrangian graphs for Tonelli Hamiltonian systems with symmetries. In particular, we consider Tonelli Hamiltonians with n independent but not necessarily involutive constants of motion and obtain two theorems reminiscent of the Liouville-Arnold theorem. Moreover, we also obtain results on the structure of the configuration spaces of such systems that are reminiscent of results on the configuration space of completely integrable Tonelli Hamiltonians.Comment: 24 pages, 1 figure; v2 corrects typo in online abstract; v3 includes new title (was: A Weak Liouville-Arnold Theorem), re-arrangement of introduction, re-numbering of main theorems; v4 updates the authors' email and physical addresses, clarifies notation in section 4. Final versio

Atomic Mass Dependence of Hadron Production in Deep Inelastic Scattering on Nuclei

Hadron production in lepton-nucleus deep inelastic scattering is studied in an absorption model. In the proposed model, the early stage of hadronization in the nuclear medium is dominated by prehadron formation and absorption, controlled by flavor-dependent formation lengths and absorption cross sections. Computations for hadron multiplicity ratios are presented and compared with the HERMES experimental data for pions, kaons, protons and antiprotons. The mass-number dependence of hadron attenuation is shown to be sensitive to the underlying hadronization dynamics. Contrary to common expectations for absorption models, a leading term proportional to A^{2/3} is found. Deviations from the leading behavior arise at large mass-numbers and large hadron fractional momenta.Comment: 30 pages, 10 figures, v2: minor changes (legend in figs 5 & 6 is added), v3: additional explanations are added, v4: Version combines v3 and the erratum hep-ph/050803

Hadron production in deep inelastic lepton-nucleus scattering

Predictions for semi-inclusive deep inelastic lepton-nucleus scattering are presented. Both the effects of gluon radiation by the struck quark and the absorption of the produced hadron are considered. The gluon radiation covers a larger window in virtuality $Q^2$ because of the increased deconfinement of quarks inside nuclei. The absorption of hadrons formed inside the nucleus is described with a flavor dependent cross section. Calculations for rescaled fragmentation functions and nuclear absorption are compared with the EMC and HERMES data for N, Cu and Kr targets with respect to the deuteron target. Predictions for Ne and Xe targets in the HERMES kinematic regime are given.Comment: 27 pages, 12 figures. Section 2 on rescaling modified. Extended discussion of the results in Sec. 5 and 6. To be published in Nucl.Phys.

Production of Secondaries in High Energy d+Au Collisions

In the framework of Quark-Gluon String Model we calculate the inclusive spectra of secondaries produced in d+Au collisions at intermediate (CERN SPS) and at much higher (RHIC) energies. The results of numerical calculations at intermediate energies are in reasonable agreement with the data. At RHIC energies numerically large inelastic screening corrections (percolation effects) should be accounted for in calculations. We extract these effects from the existing RHIC experimental data on minimum bias and central d+Au collisions. The predictions for p+Au interactions at LHC energy are also given.Comment: 18 pages and 10 figure

Cross-generational trans fat intake exacerbates UV radiation-induced damage in rat skin

AbstractWe evaluated the influence of dietary fats on ultraviolet radiation (UVR)-induced oxidative damage in skin of rats. Animals from two consecutive generations born of dams supplemented with fats during pregnancy and breastfeeding were maintained in the same supplementation: soybean-oil (SO, rich in n-6 FA, control group), fish-oil (FO, rich in n-3 FA) or hydrogenated-vegetable-fat (HVF, rich in TFA). At 90days of age, half the animals from the 2nd generation were exposed to UVR (0.25J/cm2) 3×/week for 12weeks. The FO group presented higher incorporation of n-3 FA in dorsal skin, while the HVF group incorporated TFA. Biochemical changes per se were observed in skin of the HVF group: greater generation of reactive oxygen species (ROS), lower mitochondrial integrity and increased Na+K+-ATPase activity. UVR exposure increased skin wrinkles scores and ROS generation and decreased mitochondrial integrity and reduced-glutathione levels in the HVF group. In FO, UVR exposure was associated with smaller skin thickness and reduced levels of protein–carbonyl, together with increased catalase activity and preserved Na+K+-ATPase function. In conclusion, while FO may be protective, trans fat may be harmful to skin health by making it more vulnerable to UVR injury and thus more prone to develop photoaging and skin cancer

Non-Perturbative QCD Treatment of High-Energy Hadron-Hadron Scattering

Total cross-sections and logarithmic slopes of the elastic scattering cross-sections for different hadronic processes are calculated in the framework of the model of the stochastic vacuum. The relevant parameters of this model, a correlation length and the gluon condensate, are determined from scattering data, and found to be in very good agreement with values coming from completely different sources of information. A parameter-free relation is given between total cross-sections and slope parameters, which is shown to be remarkably valid up to the highest energies for which data exist.Comment: 60 pages, Heidelberg preprin

Finite-Temperature Transport in Finite-Size Hubbard Rings in the Strong-Coupling Limit

We study the current, the curvature of levels, and the finite temperature charge stiffness, D(T,L), in the strongly correlated limit, U>>t, for Hubbard rings of L sites, with U the on-site Coulomb repulsion and t the hopping integral. Our study is done for finite-size systems and any band filling. Up to order t we derive our results following two independent approaches, namely, using the solution provided by the Bethe ansatz and the solution provided by an algebraic method, where the electronic operators are represented in a slave-fermion picture. We find that, in the U=\infty case, the finite-temperature charge stiffness is finite for electronic densities, n, smaller than one. These results are essencially those of spinless fermions in a lattice of size L, apart from small corrections coming from a statistical flux, due to the spin degrees of freedom. Up to order t, the Mott-Hubbard gap is \Delta_{MH}=U-4t, and we find that D(T) is finite for n<1, but is zero at half-filling. This result comes from the effective flux felt by the holon excitations, which, due to the presence of doubly occupied sites, is renormalized to \Phi^{eff}=\phi(N_h-N_d)/(N_d+N_h), and which is zero at half-filling, with N_d and N_h being the number of doubly occupied and empty lattice sites, respectively. Further, for half-filling, the current transported by any eigenstate of the system is zero and, therefore, D(T) is also zero.Comment: 15 pages and 6 figures; accepted for PR

Production of secondaries in soft p+pb collisions at LHC

We calculate the inclusive spectra of secondaries produced in soft (minimum bias) p+Pb collisions in the framework of Quark-Gluon String Model at LHC energy, and by taking into account the inelastic screening corrections (percolation effects). The role of these effects is expected to be very large at very high energies, and they should decrease the spectra about 3 times in the midrapidity region and increase them about 2 times in the fragmentation region at the energy of LHC.Comment: 18 pages and 10 figures. arXiv admin note: text overlap with arXiv:0802.219