Non-extensive resonant reaction rates in astrophysical plasmas

We study two different physical scenarios of thermonuclear reactions in stellar plasmas proceeding through a narrow resonance at low energy or through the low energy wing of a wide resonance at high energy. Correspondingly, we derive two approximate analytical formulae in order to calculate thermonuclear resonant reaction rates inside very coupled and non ideal astrophysical plasmas in which non-extensive effects are likely to arise. Our results are presented as simple first order corrective factors that generalize the well known classical rates obtained in the framework of Maxwell-Boltzmann statistical mechanics. As a possible application of our results, we calculate the dependence of the total corrective factor with respect to the energy at which the resonance is located, in an extremely dense and non ideal carbon plasma.Comment: 5 pages, 1 figur

New result on the measurement of the direct photon emission in K+ --> pi^+ pi^0 gamma decay

We present a new result on the K^+ --> pi^+ pi^0 gamma decay measurement using stopped kaons. The best fit to the decay spectrum comprised of 10k events gives a branching ratio for the direct photon emission of [3.8+-0.8(stat)+-0.7(syst)] times 10^{-6} in the pi^+ kinetic energy region of 55 to 90 MeV. This result has been obtained with the assumption that there is no component due to interference with the inner bremsstrahlung.Comment: 14 pages, 7 figures, 3 tables (Fig.1 which had problems with uploading first time is replaced. Besides introduction is changed to bring into accordance with the version published in Eur.Phys.J.C.

Additional J/ΨJ/\Psi Suppression from High Density Effects

At high energies the saturation effects associated to the high parton density should modify the behavior of the observables in proton-nucleus and nucleus-nucleus scattering. In this paper we investigate the saturation effects in the nuclear $J/\Psi$ production and estimate the modifications in the energy dependence of the cross section as well as in the length of the nuclear medium. In particular, we calculate the ratio of $J/\Psi$ to Drell-Yan cross sections and show that it is strongly modified if the high density effects are included. Moreover, our results are compared with the data from the NA50 Collaboration and predictions for the RHIC and LHC kinematic regions are presented. We predict an additional $J/\Psi$ suppression associated to the high density effects.Comment: 13 pages, 5 figures, version to be published in Eur. Phys. J.

Two-pion Bose-Einstein correlations in central Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV

The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/388

Propagation of Fast Partons in the Nuclear Medium

The color dipole approach has been applied in the target rest frame to address the issues of transverse momentum broadening and energy loss of a fast quark propagating in the nuclear medium. A recent application of the theory to the FermiLab E772/E866 experimental data, determining the rate of energy loss of a quark propagating in the medium to be 2 to 3 GeV/fm, will be reviewed. Calculations for the transverse momentum distribution will be presented, and the results will be compared to the E866 data. The theory will be shown to compare favorably to the data, and these results will be shown to suggest that the momentum broadening of a quark is about twice the generally accepted size.Comment: 6 pages, 4 figures, Invited talk given at 4th International Conference on Perspectives in Hadronic Physic

Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV

Inclusive transverse momentum spectra of primary charged particles in Pb-Pb collisions at $\sqrt{s_{_{\rm NN}}}$ = 2.76 TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross section. The measured charged particle spectra in $|\eta|<0.8$ and $0.3 < p_T < 20$ GeV/$c$ are compared to the expectation in pp collisions at the same $\sqrt{s_{\rm NN}}$, scaled by the number of underlying nucleon-nucleon collisions. The comparison is expressed in terms of the nuclear modification factor $R_{\rm AA}$. The result indicates only weak medium effects ($R_{\rm AA} \approx$ 0.7) in peripheral collisions. In central collisions, $R_{\rm AA}$ reaches a minimum of about 0.14 at $p_{\rm T}=6$-7GeV/$c$ and increases significantly at larger $p_{\rm T}$. The measured suppression of high-$p_{\rm T}$ particles is stronger than that observed at lower collision energies, indicating that a very dense medium is formed in central Pb-Pb collisions at the LHC.Comment: 15 pages, 5 captioned figures, 3 tables, authors from page 10, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/98

Draw Your Own Visualization

The purpose of this activity is to learn about visualizations by designing and drawing one. Students draw a visualization based either on their interests and ideas about the world or based on actual GLOBE data. They are asked to justify the design choices they make and to interpret the visualizations of their peers. Intended outcomes are that students learn to identify and communicate important patterns in a dataset by drawing a visualization, and begin to interpret those patterns. Students select and specify colors, units, and ranges of values to communicate data effectively in a visualization. Educational levels: Middle school

A Door of Hope re-opened : the Fifth Monarchy, King Charles and King Jesus

A Door of Hope was the manifesto of the Fifth Monarchists’ desperate uprising in London in January 1661, a few months after the Restoration of Charles II. While the rising itself is well known, its manifesto has never been examined in detail. Probably based on a sermon to Venner’s congregation, it displays a defiant conviction that the Restoration could be understood as part of God’s providential plan, the next step towards the imminent kingdom of Christ on earth. But it also reaches out to a much wider constituency, all the supporters of the “Good Old Cause”, offering a programme that might appeal to many radicals. And the author draws on secular, republican discourse to buttress his apocalyptic claims, revealing close links between even the most extreme Fifth Monarchists and wider currents of interregnum radicalism

Using automated source code analysis for software evolution

Software maintenance is one of the most expensive and time-consuming phases in the software life-cycle. The size and complexity of commercial applications probably present the greatest difficulty that maintainers face when making changes to their applications. As a result of the corresponding loss of understanding, business knowledge encapsulated within the system becomes fragmented, and any changes made as a result of new business initiatives become difficult to implement and hence may mean a loss of business opportunities. This paper outlines an approach to regaining understanding of software which has been used in the Release project at Durham University. This approach involves determining the calling structure of a program in terms of a call-graph, and from this call-graph extracting a dominance tree. Various problems which have been encountered during the construction of tools to perform this task are described