3,003 research outputs found
Impact analysis of TOTEM data at the LHC: black disk limit exceeded
We discuss the profile of the impact--parameter dependent elastic scattering
amplitude. Extraction of impact-parameter dependence from the dataset with
inclusion of the experimental data on elastic scattering at the LHC energies
helps to reveal the asymptotics of hadron interactions. Analysis of the data
clearly indicates that the impact-parameter elastic scattering amplitude exceed
the black disk limit at the LHC energy 7TeV and the inelastic overlap function
reaches its maximum value at Comment: 5 pages, 5 figure
On jet structure in heavy ion collisions
The LHC data on jet fragmentation function and jet shapes in PbPb collisions
at center-of-mass energy 2.76 TeV per nucleon pair are analyzed and interpreted
in the frameworks of PYQUEN jet quenching model. A specific modification of
longitudinal and radial jet profiles in most central PbPb collisions as
compared with pp data is close to that obtained with PYQUEN simulations taking
into account wide-angle radiative and collisional partonic energy loss. The
contribution of radiative and collisional loss to the medium-modified intra-jet
structure is estimated.Comment: 9 pages including 3 figures as EPS-files; prepared using LaTeX
package for publication in the European Physical Journal
Forward Physics at the LHC (Elba 2010)
The papers review the main theoretical and experimental aspects of the
Forward Physics at the Large Hadron Collider
Forward physics at the LHC (Elba 2010)
This article does not have an abstract
The politicisation of evaluation: constructing and contesting EU policy performance
Although systematic policy evaluation has been conducted for decades and has been growing strongly within the European Union (EU) institutions and in the member states, it remains largely underexplored in political science literatures. Extant work in political science and public policy typically focuses on elements such as agenda setting, policy shaping, decision making, or implementation rather than evaluation. Although individual pieces of research on evaluation in the EU have started to emerge, most often regarding policy “effectiveness” (one criterion among many in evaluation), a more structured approach is currently missing. This special issue aims to address this gap in political science by focusing on four key focal points: evaluation institutions (including rules and cultures), evaluation actors and interests (including competencies, power, roles and tasks), evaluation design (including research methods and theories, and their impact on policy design and legislation), and finally, evaluation purpose and use (including the relationships between discourse and scientific evidence, political attitudes and strategic use). The special issue considers how each of these elements contributes to an evolving governance system in the EU, where evaluation is playing an increasingly important role in decision making
First measurement of production in pp collisions at = 7 TeV
The production of the charm-strange baryon is measured for
the first time at the LHC via its semileptonic decay into e
in pp collisions at TeV with the ALICE detector. The transverse
momentum () differential cross section multiplied by the branching
ratio is presented in the interval 1 8 GeV/ at
mid-rapidity, 0.5. The transverse momentum dependence of the
baryon production relative to the D meson production is
compared to predictions of event generators with various tunes of the
hadronisation mechanism, which are found to underestimate the measured
cross-section ratio.Comment: 22 pages, 6 captioned figures, 1 table, authors from page 17,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/412
Energy dependence of exclusive photoproduction off protons in ultra-peripheral p-Pb collisions at = 5.02 TeV
The ALICE Collaboration has measured the energy dependence of exclusive
photoproduction of vector mesons off proton targets in
ultra-peripheral p-Pb collisions at a centre-of-mass energy per nucleon pair
TeV. The ee and decay channels
are used to measure the cross section as a function of the rapidity of the
in the range , corresponding to an energy in the
p centre-of-mass in the interval GeV.
The measurements, which are consistent with a power law dependence of the
exclusive photoproduction cross section, are compared to previous
results from HERA and the LHC and to several theoretical models. They are found
to be compatible with previous measurements.Comment: 25 pages, 3 captioned figures, 3 tables, authors from page 19,
published version, figures at http://alice-publications.web.cern.ch/node/455
Constraining the magnitude of the Chiral Magnetic Effect with Event Shape Engineering in Pb-Pb collisions at = 2.76$ TeV
In ultrarelativistic heavy-ion collisions, the event-by-event variation of
the elliptic flow reflects fluctuations in the shape of the initial state
of the system. This allows to select events with the same centrality but
different initial geometry. This selection technique, Event Shape Engineering,
has been used in the analysis of charge-dependent two- and three-particle
correlations in Pb-Pb collisions at TeV. The
two-particle correlator ,
calculated for different combinations of charges and , is
almost independent of (for a given centrality), while the three-particle
correlator
scales almost linearly both with the event and charged-particle
pseudorapidity density. The charge dependence of the three-particle correlator
is often interpreted as evidence for the Chiral Magnetic Effect (CME), a parity
violating effect of the strong interaction. However, its measured dependence on
points to a large non-CME contribution to the correlator. Comparing the
results with Monte Carlo calculations including a magnetic field due to the
spectators, the upper limit of the CME signal contribution to the
three-particle correlator in the 10-50% centrality interval is found to be
26-33% at 95% confidence level.Comment: 20 pages, 6 captioned figures, 1 tables, authors from page 15,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/382
- …