Effect of hard processes on momentum correlations

The effect of hard processes to be encountered in HBT studies at the Large Hadron Collider have been studied. A simple simulation has allowed us to generate momentum correlations involving jet particles as well as particles originating from the kinetic freeze out and to compare them to a simple theoretical model which has been developed. The first results on the effect of hard processes on the correlation function for the case of jet quenching are presented.Comment: 9 pages, 12 figures, talk presented at 2nd Warsaw Meeting on Particle Correlations and Resonances in Heavy Ion Collision

Improving the precision of linear optics measurements based on turn-by-turn beam position monitor data after a pulsed excitation in lepton storage rings

Beam optics control is of critical importance for machine performance and protection. Nowadays, turn-by-turn (TbT) beam position monitor (BPM) data are increasingly exploited as they allow for fast and simultaneous measurement of various optics quantities. Nevertheless, so far the best documented uncertainty of measured ß -functions is of about 10‰ rms. In this paper we compare the ß -functions of the ESRF storage ring measured from two different TbT techniques—the N-BPM and the Amplitude methods—with the ones inferred from a measurement of the orbit response matrix (ORM). We show how to improve the precision of TbT techniques by refining the Fourier transform of TbT data with properly chosen excitation amplitude. The precision of the N-BPM method is further improved by refining the phase advance measurement. This represents a step forward compared to standard TbT measurements. First experimental results showing the precision of ß -functions pushed down to 4‰ both in TbT and ORM techniques are reported and commented.Postprint (published version

Test of machine learning at the CERN LINAC4

The CERN H− linear accelerator, LINAC4, served as a test bed for advanced algorithms during the CERN Long Shutdown 2 in the years 2019/20. One of the main goals was to show that reinforcement learning with all its benefits can be used as a replacement for numerical optimization and as a complement to classical control in the accelerator control context. Many of the algorithms used were prepared before- hand at the electron line of the AWAKE facility to make the best use of the limited time available at LINAC4. An overview of the algorithms and concepts tested at LINAC4 and AWAKE will be given and the results discussed.peer-reviewe

Operating the LHC off-momentum for p-pb collisions

The first high-luminosity p-Pb run at the LHC took place in January-February 2013 at 4 Z TeV energy per beam. The RF frequency difference of proton and Pb is about 60 Hz for equal magnetic rigidities at that energy, which means that beams move to slightly off-momentum, non-central, orbits during physics when frequencies are locked together. The resulting optical perturbations ("beta-beating") restrict the available aperture and required a special correction. This was also the first operation of the LHC with low beta function in all four experiments and it required a specific collimation set up. Predictions from offline calculations of beta-beating correction are compared with measurements during the optics commissioning and collimator set-up.Asian Committee for Future Accelerators (ACFA),American Physical Society Division of Physics of Beams (APS-DPB),Chinese Academy of Sciences (CAS),European Physical Society Accelerator Group (EPS-AG)peer-reviewe

El neopragmatistmo de Richard Rorty como un tipo de humanismo

the author analizes the workof Richard Rorty and his european reception with the aim of showing how his neopragmatist could be undestrood as a mode of humanism that can face the new challenges of our age.el autor analiza la obra de Richard Rorty y su recepción europea con la intención de mostrar su neopragmatismo como una forma de humanismo que trate de hacer frente a los nuevos retos que muestra nuestra época