The Continuous Challenge of Enlargement. EIPAscope 01/2011

The ‘big bang’ enlargement of 2004, followed by the accession of Romania and Bulgaria in 2007, has profoundly altered the way the European Union functions. But with hindsight, it turned out that none of the often apocalyptic scenarios predicted before 2004 has materialised: neither was the EU-15 widely swamped with a flood of migrants from its new member countries, nor was the EU budget blooded to death, nor have its structures become paralysed. However, public opinion – and thus politicians – in the old member states give little credit to enlargement, and there is limited appetite for promoting the accession of further member states. This article tries to analyse the reasons behind the lack of appetite of most EU member states for further enlargement. It will challenge some of the conventional perceptions of enlargement and propose a double approach to get the process back on track: by tackling political challenges from a technical angle and by paying more attention to the perception of enlargement related problems

The New Instrument for Pre-Accession Assistance (IPA II): Less Accession, More Assistance?. EIPA Working Paper 2014/W/01

The EU enlargement engine seems to have run out of political steam. Support within the member countries for future enlargement is at all-time low, while some of the candidate countries have also seemed to put the enlargement process on the backburner. However, at least rhetorically, the EU is still committed to the enlargement process and maintains its entire enlargement tool box, such as the Instrument for Pre-Accession (IPA) – one of the most important EU external financial instruments. The new IPA regulation (IPA II), adopted in March 20141, clearly reflects the fact that the enlargement process is on a holding pattern

Streamlining of Policies or Additional Level of Complexity? The Impact of the EEAS on EU - Western Balkans Relations

Through the creation of a European External Action Service (EEAS) the EU has attempted to increase the consistency and visibility of its external action abroad. However, in the Western Balkans the impact of this new diplomatic service of the EU is not always obvious: EU enlargement, as the dominating policy framework, remains outside the EEAS’ scope of competence. In Kosovo and Bosnia, with their strong CFSP dimension, synergies are still limited. Whereas the mutation of the EC Delegations into EU Delegations under the authority of the EEAS (but with a strong Commission component) had the benefit of raising the EU’s visibility in the Western Balkans, questions remain about internal coordination and the risk of a possible hijacking of the new service by member states. Although the EEAS can facilitate the streamlining the EU’s external action in the Western Balkans, such an outcome depends more on the behaviour of the actors involved than on institutional arrangements

DFB Lasers Between 760 nm and 16 μm for Sensing Applications

Recent years have shown the importance of tunable semiconductor lasers in optical sensing. We describe the status quo concerning DFB laser diodes between 760 nm and 3,000 nm as well as new developments aiming for up to 80 nm tuning range in this spectral region. Furthermore we report on QCL between 3 μm and 16 μm and present new developments. An overview of the most interesting applications using such devices is given at the end of this paper

MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe

Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe

Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV