PICOSEC: Charged particle timing at sub-25 picosecond precision with a Micromegas based detector

The prospect of pileup induced backgrounds at the High Luminosity LHC (HL-LHC) has stimulated intense interest in developing technologies for charged particle detection with accurate timing at high rates. The required accuracy follows directly from the nominal interaction distribution within a bunch crossing ( σz∼5 cm, σt∼170 ps). A time resolution of the order of 20–30 ps would lead to significant reduction of these backgrounds. With this goal, we present a new detection concept called PICOSEC, which is based on a “two-stage” Micromegas detector coupled to a Cherenkov radiator and equipped with a photocathode. First results obtained with this new detector yield a time resolution of 24 ps for 150 GeV muons, and 76 ps for single photoelectrons.Peer Reviewe

LHC Forward Physics

The goal of this report is to give a comprehensive overview of the rich field of forward physics, with a special attention to the topics that can be studied at the LHC. The report starts presenting a selection of the Monte Carlo simulation tools currently available, chapter 2, then enters the rich phenomenology of QCD at low, chapter 3, and high, chapter 4, momentum transfer, while the unique scattering conditions of central exclusive production are analyzed in chapter 5. The last two experimental topics, Cosmic Ray and Heavy Ion physics are presented in the chapter 6 and 7 respectively. Chapter 8 is dedicated to the BFKL dynamics, multiparton interactions, and saturation. The report ends with an overview of the forward detectors at LHC. Each chapter is correlated with a comprehensive bibliography, attempting to provide to the interested reader with a wide opportunity for further studies.Peer Reviewe

A New Scintillator Tile/Fiber Preshower Detector for the CDF Central Calorimeter

A detector designed to measure early particle showers has been installed in front of the central CDF calorimeter at the Tevatron. This new preshower detector is based on scintillator tiles coupled to wavelength-shifting fibers read out by multi-anode photomultipliers and has a total of 3,072 readout channels. The replacement of the old gas detector was required due to an expected increase in instantaneous luminosity of the Tevatron collider in the next few years. Calorimeter coverage, jet energy resolution, and electron and photon identification are among the expected improvements. The final detector design, together with the R&D studies that led to the choice of scintillator and fiber, mechanical assembly, and quality control are presented. The detector was installed in the fall 2004 Tevatron shutdown and started collecting colliding beam data by the end of the same year. First measurements indicate a light yield of 12 photoelectrons/MIP, a more than two-fold increase over the design goals.Comment: 5 pages, 10 figures (changes are minor; this is the final version published in IEEE-Trans.Nucl.Sci.

Financial sustainability and profitability of supercritical CO2 pasteurization of liquid products: A case study

This work presents an analysis of a supercritical CO2 (SC-CO2) pasteurization process, focusing on the financial and economic parameters that make the process sustainable at an industrial level. A small company processing 5,000,000 bottles of apple juice per year has been chosen as a case study. Investment and operating costs have been estimated based on data collected from the market and the relevant economic literature. The financial sustainability assessment was performed through the Discounted Cash Flow methodology, proving that SC-CO2 pasteurization is profitable on a 10-year horizon. The Net Present Value is strictly positive and the Internal Rate of Return higher than the cost of funding. The sensitivity analysis shows the robustness of this study to possible changes in the model parameters. Overall, this work demonstrates SC-CO2 pasteurization to be profitable and, considering the current growth of the high-nutritional value fruit juice market, it suggests positive financial returns for both incumbents and new entrants

Central exclusive production of scalar \chi_c meson at the Tevatron, RHIC and LHC energies

We calculate several differential distributions for exclusive double diffractive $\chi_c(0^{++})$ production in proton-antiproton collisions at the Tevatron and in proton-proton collisions at RHIC and LHC in terms of unintegrated gluon distributions (UGDFs) within the $k_t$-factorisation approach. The uncertainties of the Khoze-Martin-Ryskin approach are discussed in detail. The $g^* g^* \to \chi_c(0^{++})$ transition vertex is calculated as a function of gluon virtualities applying the standard pNRQCD technique. The off-shell effects are discussed and quantified. They lead to a reduction of the cross section by a factor 2--5, depending on the position in the phase space and UGDFs. Different models of UGDFs are used and the results are shown and discussed. The cross section for diffractive component depends strongly on UGDFs. We calculate also the differential distributions for the $\gamma^* \gamma^* \to \chi_c(0^{++})$ fusion mechanism. The integrated cross section for photon-photon fusion is much smaller than that of diffractive origin. The two components have very different dependence on momentum transfers $t_1, t_2$ in the nucleon lines as well as azimuthal-angle correlations between both outgoing nucleons.Comment: 34 pages, 23 figures, 2 table

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

Study of the electron trigger efficiency of the CMS Experiment using test beam data

A study of the electron identification and selection efficiency of the L1 Trigger algorithm has been performed using the combined ECAL/HCAL test beam data. A detailed discussion of the electron isolation and its impact on the selection efficiency is presented. The L1 electron algorithm is studied for different beam energies and the results indicate that efficiencies of 98% or more can be achieved for electrons with energies between 15 and 100 GeV. The fraction of charged hadrons with energies from 3 up to 100 GeV rejected by the L1 electron trigger algorithm is estimated to be larger than 93%.Comment: 22 pages, 14 figure

Homeostatic control of synaptic rewiring in recurrent networks induces the formation of stable memory engrams

Brain networks store new memories using functional and structural synaptic plasticity. Memory formation is generally attributed to Hebbian plasticity, while homeostatic plasticity is thought to have an ancillary role in stabilizing network dynamics. Here we report that homeostatic plasticity alone can also lead to the formation of stable memories. We analyze this phenomenon using a new theory of network remodeling, combined with numerical simulations of recurrent spiking neural networks that exhibit structural plasticity based on firing rate homeostasis. These networks are able to store repeatedly presented patterns and recall them upon the presentation of incomplete cues. Storage is fast, governed by the homeostatic drift. In contrast, forgetting is slow, driven by a diffusion process. Joint stimulation of neurons induces the growth of associative connections between them, leading to the formation of memory engrams. These memories are stored in a distributed fashion throughout connectivity matrix, and individual synaptic connections have only a small influence. Although memory-specific connections are increased in number, the total number of inputs and outputs of neurons undergo only small changes during stimulation. We find that homeostatic structural plasticity induces a specific type of “silent memories”, different from conventional attractor states

Diffractive χ\chi Production at the Tevatron and the LHC

We present predictions for the diffractive production of $\chi$ mesons in the central rapidity region usually covered by collider detectors. The predicted cross sections are based on the Bialas-Landshoff formalism for both exclusive and inclusive production and makes use of the DPEMC Monte-Carlo simulation adapted with kinematics appropriate for small-mass diffractive production. We compare generator-level results with a CDF measurement for exclusive $\chi$ production, and study background and other scenarios including the contribution of inclusive $\chi$ production. The results agree with the Tevatron data and are extrapolated, highlighting the exclusive \chic production at LHC energies. A possible new measurement at the Tevatron using the D{\O}forward detectors is investigated, taking advantage of the dominance of exclusive production for high enough diffractive mass fraction.Comment: 9 pages, 2 figures, added akcnowledgment