HEP in Greek Classes

The HEP Inquiry learning resources created over the last four years by the European outreach projects are reviewed. The resources are mostly addressed to high school students and the purpose is to ignite their interest on science. In addition, at the University of Athens for the last four years we have been using the HYPATIA online event analysis tool as a lab course for fourth year undergraduate physics students, majoring in HEP. Each year 40–50 students highly appreciated the course, since they get a direct involvement in the actual toplevel research. Up to now, the course was limited to visual inspection of a few tens of ATLAS events. Recently we have enriched the course with additional analysis exercises, which involve large samples of events. The students, through a user friendly interface can analyze the samples (both signal and background ones) and optimize the cut selection in order to search for the Higgs decay H □ 4 leptons. Recently ATLAS released 1/fb of data, so starting now the students analyse real data

Interpenetrated networks from a novel nanometer-sized pseudopeptidic ligand, bridging water, and transition metal ions with CdSO4 topology.

The combination of a new pseudopeptidic ligand, transition metal ions, and bridging water molecules results in the formation of [M(m-TBG)(m-H2O)(H2O)2]?2H2O (M: Cu, Co and H2TBG: terephthaloylbisglycine); both compounds show rare two-fold interpenetrated three-dimensional cds-nets and reversible loss of coordinated and lattice water molecule

Evaluation of CT-DEA performance on Ca/P ratio assessment in bone apatite using EDX

The aim of this study is to evaluate the performance of a new computed tomography-dual energy analysis (CT-DEA) technique developed for the non-invasive assessment of the 3D spatial distribution of calcium/phosphorus (Ca/P) ratio in bone. For this, the Ca/P ratio in 58 regions from four healthy and four inflammation-mediated osteoporotic (IMO) rabbit bone collagen-free samples were assessed using energy dispersive X-ray spectroscopy (EDX) and CT-DEA. Image registration, performed using NifTK software (Centre for Medical Imaging Computing, University College London), allowed the comparison with the results from the two imaging systems.A value of R=0.69 in the fit of CT-DEA Ca/P ratio versus EDX Ca/P ratio and a mean absolute/percentage difference of 0.11 ± 0.08/8 ± 6% in the CT-DEA Ca/P ratio from the EDX results suggest sufficient confidence in the current experimental capabilities of the developed technique. The main difficulties in the comparison of the results using the two techniques and possible sources of error are discussed.Even though there are still possible improvements that can be made in the developed technique, through this study, it has been shown that CT-DEA can provide valuable 3D, non-invasive information on the comparison between healthy and osteoporotic bone. © 2014 The Authors

Structural Properties, Cytotoxicity, and Anti-Inflammatory Activity of Silver(I) Complexes with tris(p-tolyl)Phosphine and 5-Chloro-2-Mercaptobenzothiazole

The synthesis and characterization of the silver(I) chloride complex of formula {[AgCI(CMBZT)(TPTP)2] · (MeOH)} (1) (CMBZT = 5-chloro-2-mercaptobenzothiazole, TPTP = tris(p-tolyl)phosphine) is described. Also the structure of the hydrate derivative {[AgCI(TPTP)3] · (0.5 · H2O)} (2) of the corresponding known anhydrous silver complex (Zartilas et al., 2009), and the polymorph 3 of the known [AgI(TPTP)3] complex (Zartilas et al., 2009) were determined and compared with the known ones. In addition, the structure of the known one silver(I) cluster {[AgI(TPTP)]4} (4) (Meijboom et al., 2009) was re-determined at 120(2) K and possible Ag-Ag interactions were analyzed. The compounds 1–4 were characterized by X-ray crystallography at r.t (1) and 120 K (2–4). All these complexes and {[(Et3NH)+]2 · [Ag6(μ3-Hmna)4(μ3-mna)2]2− · (DMSO)2 · (H2O)} (5) (Hmna = 2-mercaptonicotinic acid) were evaluated for cytotoxic and anti-inflammatory activity. The in vitro testing of cytotoxic activity of 1–5 against leiomyosarcoma cancer cells (LMS), were evaluated with Trypan Blue and Thiazolyl Blue Tetrazolium Bromide or 3-(4.5-dimethylthiazol-2-yl)-2.5-diphenyltetrazolium bromide (MTT) assays. The flow cytometry assay for complex 1 and showed that at 15 μM of 1, 62.38% of LMS cells undergo apoptosis, while 7% of LMS cells undergo cell necrosis. The antitumor activity of 3 is comparable with that of its reported polymorph (Zartilas et al., 2009). The anti-inflammatory, activity of complexes 1–3 and 5 was also studied. The activity towards cell viability was 2 > 3 > 5 > 1 > 4, while the order of the inhibitory activity in cell growth proliferation follows the order, 2 > 3 > 1 > 4 > 5. The anti-inflammatory activity on the other hand is 1 > 2 > 5 > ⋯ >3

A QCD space-time analysis of quarkonium formation and evolution in hadronic collisions

The production of heavy quarkonium as QQbar bound-states in hadron-hadron collisions is considered within the framework of a space-time description, combining parton-cascade evolution with a coalescence model for bound-state formation. The `hard' production of the initial QQbar, directly or via gluon fragmentation and including both color-singlet and color-octet contributions, is calculated from the PQCD cross-sections. The subsequent development of the QQbar system is described within a space-time generalization of the DGLAP parton-evolution formalism in position- and momentum-space. The actual formation of the bound-states is accomplished through overlap of the QQbar pair and a spectrum of quarkonium wave-functions. This coalescence can only occur after sufficent gluon radiation reduces the QQbar relative velocity to a value commensurate with the non-relativistic kinematics of these bound systems. The presence of gluon participants in the cascade then is both necessary and leads to the natural inclusion of both color-singlet and color-octet mechanisms. The application of this approach to pp (ppbar) collisions from sqrt(s)= 30 GeV - 14 TeV reveals very decent agreement with available data from ISR and Tevatron - without the necessity of introducing fit parameters. Moreover, production probabilities are calculated for a complete spectrum of charmonium and bottonium states, with the relative significance compared to open charm (bottom) production. An analysis of the space-time development is carried through which sheds light on the relevance of gluon radiation and color-structure, suggesting a correponding experimental investigation.Comment: 37 pages including 16 postscript figure

Analysis of charmonium production at fixed-target experiments in the NRQCD approach

We present an analysis of the existing data on charmonium hadro-production based on non-relativistic QCD (NRQCD) calculations at the next-to-leading order (NLO). All the data on J/psi and psi' production in fixed-target experiments and on pp collisions at low energy are included. We find that the amount of color octet contribution needed to describe the data is about 1/10 of that found at the Tevatron

Hadroproduction and Polarization of Charmonium

In the limit of heavy quark mass, the production cross section and polarization of quarkonia can be calculated in perturbative QCD. We study the $p_\perp$-averaged production of charmonium states in $\pi N$ collisions at fixed target energies. The data on the relative production rates of \jp and $\chi_J$ is found to disagree with leading twist QCD. The polarization of the \jp indicates that the discrepancy is not due to poorly known parton distributions nor to the size of higher order effects ($K$-factors). Rather, the disagreement suggests important higher twist corrections, as has been surmised earlier from the nuclear target $A$-dependence of the production cross section.Comment: 19 page

J/Psi Suppression in Heavy Ion Collisions at the CERN SPS

We reexamine the production of J/Psi and other charmonium states for a variety of target-projectile choices at the SPS. For this study we use a newly constructed cascade code LUCIFER II, which yields acceptable descriptions of both hard and soft processes, specifically Drell-Yan and hidden charm production, and soft energy loss and meson production, at the SPS. Glauber calculations of other authors are redone, and compared directly to the cascade results. The modeling of the charmonium states differs from that of earlier workers in its unified treatment of the hidden charm meson spectrum, which is introduced from the outset as a set of coupled states. The result is a description of the NA38 and NA50 data in terms of a conventional hadronic picture. The apparently anomalous suppression found in the most massive Pb+Pb system arises from three sources: destruction in the initial nucleon-nucleon cascade, use of coupled channels to exploit the larger breakup in the less bound Chi and Psi' states, and comover interaction in the final low energy phase.Comment: 36 pages (15 figures

High-p_T pion and kaon production in relativistic nuclear collisions

High-p_T pion and kaon production is studied in relativistic proton-proton, proton-nucleus, and nucleus-nucleus collisions in a wide energy range. Cross sections are calculated based on perturbative QCD, augmented by a phenomenological transverse momentum distribution of partons (``intrinsic k_T''). An energy dependent width of the transverse momentum distribution is extracted from pion and charged hadron production data in proton-proton/proton-antiproton collisions. Effects of multiscattering and shadowing in the strongly interacting medium are taken into account. Enhancement of the transverse momentum width is introduced and parameterized to explain the Cronin effect. In collisions between heavy nuclei, the model over-predicts central pion production cross sections (more significantly at higher energies), hinting at the presence of jet quenching. Predictions are made for proton-nucleus and nucleus-nucleus collisions at RHIC energies.Comment: 26 pages in Latex, 19 EPS figure

Bottomonium and Drell-Yan production in p-A collisions at 450 GeV

The NA50 Collaboration has measured heavy-quarkonium production in p-A collisions at 450 GeV incident energy (sqrt(s) = 29.1 GeV). We report here results on the production of the Upsilon states and of high-mass Drell-Yan muon pairs (m > 6 GeV). The cross-section at midrapidity and the A-dependence of the measured yields are determined and compared with the results of other fixed-target experiments and with the available theoretical estimates. Finally, we also address some issues concerning the transverse momentum distributions of the measured dimuons.Comment: 18 pages, 9 figures, to be published in Phys. Lett.