Exclusive DDˉD \bar D meson pair production in peripheral ultrarelativistic heavy ion collisions

The cross sections for exclusive $D^+D^-$ and $D^0 \bar {D^0}$ meson pair production in peripheral nucleus - nucleus collisions are calculated and several differential distributions are presented. The calculation of the elementary $\gamma \gamma \to D \bar D$ cross section is done within the heavy-quark approximation and in the Brodsky- Lapage formalism with distribution amplitudes describing recent CLEO data on leptonic $D^+$ decay. Realistic (Fourier transform of charge density) charge form factors of nuclei are used to generate photon flux factors. Absorption effects are discussed and quantified. The cross sections of a few nb are predicted for RHIC and of a few hundreds of nb for LHC with details depending on the approximation made in calculating elementary $\gamma \gamma \to D \bar D$ cross sections.Comment: 11 pages, 8 figure

Exclusive production of lepton, quark and meson pairs in peripheral ultrarelativistic heavy ion collisions

We discuss exclusive production of lepton-antilepton, quark-antiquark, $\pi \pi$ and $\rho^0 \rho^0$ pairs in ultraperipheral, ultrarelativistic heavy-ion collisions. The cross sections for exclusive production of pairs of particles is calculated in Equivalent Photon Approximation (EPA). Realistic (Fourier transform of charge density) charge form factors of nuclei are used and the corresponding results are compared with the cross sections calculated with monopole form factor used in the literature. Absorption effects are discussed and quantified. The cross sections obtained with realistic form factors are significantly smaller than those obtained with the monopole form factors.Comment: 9 pages, 13 figures an invited talk at the international conference "Hadron Structure 2011", Slovakia, June 201

Exclusive production of large invariant mass pion pairs in ultraperipheral ultrarelativistic heavy ion collisions

The cross section for exclusive production of $\pi^+ \pi^-$ and $\pi^0 \pi^0$ meson pairs in ultrarelativistic heavy ion collisions is calculated for LHC energy $\sqrt{s_{NN}} =$ 3.5 TeV taking into account photon-photon mechanism. We concentrate on the production of large two-pion invariant masses where the mechanism of the elementary $\gamma \gamma \to \pi \pi$ process is not fully understood. In order to include a size of nuclei we perform calculation in the impact-parameter equivalent photon approximation (EPA). Realistic charge densities are used to calculate charged form factor of $^{208}$Pb nucleus and to generate photon fluxes associated with ultrarelativistic heavy ions. Sizeable cross sections are obtained that can be measured at LHC. The cross section for elementary $\gamma \gamma \to \pi \pi$ is calculated in the framework of pQCD Brodsky-Lepage (BL) mechanism with the distribution amplitude used to descibe recent data of the BABAR collaboration on pion transition form factor, using hand-bag mechanism advocated to describe recent Belle data as well as $t$ and $u$-channel meson/reggeon exchanges. We present distributions in two-pion invariant mass as well as the pion pair rapidity for the nuclear process.Comment: 13 pages, 10 figure

Woodland Management Practices in Bronze Age, Bruszczewo, Poland

The article presents a study of wood excavated from archaeological site in Poland (2100–1650 BC). The large amount of collected samples created a unique opportunity for research because the subfossil wood was in very good preservation state. This made it possible to carry out dendrotypological analysis. This is the first such study conducted for Early Bronze Age timber originating from Poland. The main goal of the study was to determine whether the presence of strong and abrupt reductions and releases of growth, observed within tree-ring sequences, is due to natural stand dynamics, results from the influence of extreme environmental factors or whether they should be linked to specific silvicultural practices already known in ancient times. Another purpose of the study was to determine the type of forest management techniques applied to the trees growing in Bruszczewo site. The research was conducted using the dendrochronological method. In addition to the measurements of growth-ring width, the development of earlywood and latewood zones, the proportion of sapwood and the presence of specific features of tree trunks were analysed. A detailed study allowed identifying the samples originating from coppiced and shredded trees. A characteristic feature of the trees subjected to these silvicultural practices is the presence of strong and abrupt reductions and releases of growth. Moreover, coppiced trees were specified by the large proportion of sapwood in the cross-section of the stem, reduced number of sapwood rings, small and numerous earlywood vessels, diminished earlywood vessels area. In turn, shredded trees distinguished themselves by a strong reduction in the earlywood width in the years following the shredding event. The research of archaeological wood from the ancient settlement proves that during the Early Bronze Age various forest management techniques were used in this site. These treatments were aimed at improving the quality and quantity of the raw material harvested from forest area

The Activity of the National Bank of Agriculture in the General Government

In this article we try to estimate the activity of the banking institution in the General Government which used the pre-war apparatus of The National Bank of Agriculture. The bank was one ofthe largest banks realising the aim delineated by the government of the Second Polish Republic, such as the support of agricultural reform in the mid-war period. German authorities in the General Government used assets of the bank for other tasks. They were eager to use The National Bank of Agriculture and the Polish staff employed in the bank in order to liquidate fast and effectively the mid-war assets of the bank. Leaving The National Bank of Agriculture was also good for Polish staff in the bank. Raising pre-war debts was the only way to guarantee salary and pensions forthe employees of the National Bank of Agriculture and taking care of them in the hard life of occupation. The activity of the National Bank of Agriculture in the General Government was also profitable for a part of debtors as they could pay the pre-war credits earlier. One reason for agriculture farms becoming poorer and even ruined was war actions and the occupation. However, the farmers could save money and gather capital more easily. When they often sold food in secret, they got a large amount of money. In many cases, paying back the pre-war debt was the only reasonable way of getting rid of almost valueless money, although it did not mean that it was done without doubts. In the beginning, many people claimed that they would give it back to whom they had borrowed from. However, after a while the patriotism of farmers who were debtors was overcome by the willingness to have no debts and leave children in a new condition. The period of German occupation and increasing inflation was used for paying back the debt in valueless money, not only by farmers but also by owners of the large mansions such as Earl Adam Branicki