Observation and measurements of the production of prompt and non-prompt J/ψ mesons in association with a Z boson in pp collisions at s√ = 8 TeV with the ATLAS detector

The production of a Z boson in association with a J/ψ meson in proton--proton collisions probes the production mechanisms of quarkonium and heavy flavour in association with vector bosons, and allows studies of multiple parton scattering. Using 20.3fb−1 of data collected with the ATLAS experiment at the LHC, in pp collisions at s√=8 TeV, the first measurement of associated Z+J/ψ production is presented for both prompt and non-prompt J/ψ production, with both signatures having a significance in excess of 5σ. The inclusive production cross-sections for Z boson production (in μ+μ− or e+e− decay modes) in association with prompt and non-prompt J/ψ(→μ+μ−) are measured relative to the inclusive production rate of Z bosons in the same fiducial volume to be (88±16±6)×10−8 and (157±22±10)×10−8 respectively. Normalised differential production cross-sections are also determined as a function of the J/ψ transverse momentum. The fraction of signal events arising from single and double parton scattering is estimated, and a lower limit of 5.3 (3.7)mb at 68 (95) confidence level is placed on the effective cross-section regulating double parton interactions.

Search for anomalous production of prompt same-sign lepton pairs and pair-produced doubly charged Higgs bosons with s√ = 8 TeV pp collisions using the ATLAS detector

A low-background inclusive search for new physics in events with same-sign dileptons is presented. The search uses proton--proton collisions corresponding to 20.3 fb−1 of integrated luminosity taken in 2012 at a centre-of-mass energy of 8 TeV with the ATLAS detector at the LHC. Pairs of isolated leptons with the same electric charge and large transverse momenta of the type e±e±,e±μ±, and μ±μ± are selected and their invariant mass distribution is examined. No excess of events above the expected level of Standard Model background is found. The results are used to set upper limits on the cross sections for processes beyond the Standard Model. Limits are placed as a function of the dilepton invariant mass within a fiducial region corresponding to the signal event selection criteria. Exclusion limits are also derived for a specific model of doubly charged Higgs boson production.

Prompt Payments by Government Departments pursuant to Government Decision No. S29296 of May 2009

Prompt Payments by Government Departments pursuant to Government Decision No. S29296 of May 2009 Click here to download PDF 22kb

Measurement of the relative rate of prompt χ c0, χ c1 and χ c2 production at TeV

Prompt production of charmonium χ c0, χ c1 and χ c2 mesons is studied using proton-proton collisions at the LHC at a centre-of-mass energy of TeX TeV. The χ c mesons are identified through their decay to J/ψγ, with J/ψ → μ + μ − using photons that converted in the detector. A data sample, corresponding to an integrated luminosity of 1.0 fb−1 collected by the LHCb detector, is used to measure the relative prompt production rate of χ c1 and χ c2 in the rapidity range 2.0 < y < 4.5 as a function of the J/ψ transverse momentum from 3 to 20 GeV/c. First evidence for χ c0 meson production at a high-energy hadron collider is also presented.

Diagnostic performance of 3D TSE MRI versus 2D TSE MRI of the knee at 1.5 T, with prompt arthroscopic correlation, in the detection of meniscal and cruciate ligament tears

Abstract Objective: To compare the diagnostic performance of the three-dimensional turbo spin-echo (3D TSE) magnetic resonance imaging (MRI) technique with the performance of the standard two-dimensional turbo spin-echo (2D TSE) protocol at 1.5 T, in the detection of meniscal and ligament tears. Materials and Methods: Thirty-eight patients were imaged twice, first with a standard multiplanar 2D TSE MR technique, and then with a 3D TSE technique, both in the same 1.5 T MRI scanner. The patients underwent knee arthroscopy within the first three days after the MRI. Using arthroscopy as the reference standard, we determined the diagnostic performance and agreement. Results: For detecting anterior cruciate ligament tears, the 3D TSE and routine 2D TSE techniques showed similar values for sensitivity (93% and 93%, respectively) and specificity (80% and 85%, respectively). For detecting medial meniscal tears, the two techniques also had similar sensitivity (85% and 83%, respectively) and specificity (68% and 71%, respectively). In addition, for detecting lateral meniscal tears, the two techniques had similar sensitivity (58% and 54%, respectively) and specificity (82% and 92%, respectively). There was a substantial to almost perfect intraobserver and interobserver agreement when comparing the readings for both techniques. Conclusion: The 3D TSE technique has a diagnostic performance similar to that of the routine 2D TSE protocol for detecting meniscal and anterior cruciate ligament tears at 1.5 T, with the advantage of faster acquisition.

Prompt electron emission and collisional ionization of ambient gas during pulsed laser ablation of silver

A silver target kept under partial vacuum conditions was irradiated with focused nanosecond pulses at 1:06 mm from a Nd:YAG laser. The electron emission monitored with a Langmuir probe shows a clear twin-peak distribution. The first peak which is very sharp has only a small delay and it indicates prompt electron emission with energy as much as 60 5 eV. Also the prompt electron emission shows a temporal profile with a width that is same as that for the laser pulse whereas the second peak is broader, covers several microseconds, and represents the low-energy electrons (2 0:5 eV) associated with the laser-induced silver plasma as revealed by time-of-flight measurements. It has been found that prompt electrons ejected from the target collisionally excite and ionize ambient gas molecules. Clearly resolved rotational structure is observed in the emission spectra of ambient nitrogen molecules. Combined with time-resolved spectroscopy, the prompt electrons can be used as excitation sources for various collisional excitation–relaxation experiments. The electron density corresponding to the first peak is estimated to be of the order of 1017 cm?--3 and it is found that the density increases as a function of distance away from the target. Dependence of probe current on laser intensity shows plasma shielding at high laser intensities.

Banking Union: A Federal Model for the European Union with Prompt Corrective Action. CEPS Policy Brief No. 282, 18 September 2012

The European Commission has published its proposals for the transfer of supervisory responsibilities to the European Central Bank (ECB),1 under Article 127(6) of the TFEU, providing a comprehensive and courageous ‘first step’ towards a European banking Union, the other steps being European deposit insurance and resolution procedures. However, on a number of issues the Commission’s chosen path raises questions that should be brought out in the open and fully recognized before final deliberation by the Council.

The prompt hypothesis: clarification requests as corrective input for grammatical errors

The potential of clarification questions (CQs) to act as a form of corrective input for young children's grammatical errors was examined. Corrective responses were operationalized as those occasions when child speech shifted from erroneous to correct (E -> C) contingent on a clarification question. It was predicted that E -> C sequences would prevail over shifts in the opposite direction (C -> E), as can occur in the case of nonerror-contingent CQs. This prediction was tested via a standard intervention paradigm, whereby every 60s a sequence of two clarification requests (either specific or general) was introduced into conversation with a total of 45 2- and 4-year-old children. For 10 categories of grammatical structure, E -> C sequences predominated over their C -> E counterparts, with levels of E -> C shifts increasing after two clarification questions. Children were also more reluctant to repeat erroneous forms than their correct counterparts, following the intervention of CQs. The findings provide support for Saxton's prompt hypothesis, which predicts that error-contingent CQs bear the potential to cue recall of previously acquired grammatical forms.