Event by Event analysis of Maximum Pseudo-rapidity Gap Fluctuation in High energy Nucleus-nucleus Collisions

A study of Event by Event analysis of maximum Pseudo-rapidity Gap Fluctuation in heavy-ion collisions in terms of the scaled variance {\omega} has been carried out for relativistic AA collisions with multiplicity cut (N >10) using nuclear emulsion data at 4.5 AGeV/c. The values of scaled variance are found to be greater than zero indicating the presence of strong fluctuation of maximum rap gap values in the multiparticle production process. The event by event fluctuations are found to decrease with the increase of average multiplicity of the interactions. Experimental analysis has been compared with the results obtained from the analysis of events simulated by generating random numbers (MC-RAND events) and also by Ultra Relativistic Quantum Molecular Dynamics (UrQMD) model. UrQMD model simulated values of event by event fluctuations of maximum rapidity gap are less than the corresponding experimental values.Comment: 1 figure. arXiv admin note: substantial text overlap with arXiv:1802.0675

Development of proton beam irradiation system for the NA65/DsTau experiment

Tau neutrino is the least studied lepton of the Standard Model (SM). The NA65/DsTau experiment targets to investigate $D_s$, the parent particle of the $\nu_\tau$, using the nuclear emulsion-based detector and to decrease the systematic uncertainty of $\nu_\tau$ flux prediction from over 50% to 10% for future beam dump experiments. In the experiment, the emulsion detectors are exposed to the CERN SPS 400 GeV proton beam. To provide optimal conditions for the reconstruction of interactions, the protons are required to be uniformly distributed over the detector's surface with an average density of $10^5~\rm{cm^{-2}}$ and the fluctuation of less than 10%. To address this issue, we developed a new proton irradiation system called the target mover. The new target mover provided irradiation with a proton density of $0.98~\rm{cm^{-2}}$ and the density fluctuation of $2.0\pm 0.3$% in the DsTau 2021 run.Comment: 9 pages, 16 figure

DsTau: Study of tau neutrino production with 400 GeV protons from the CERN-SPS

In the DsTau experiment at the CERN SPS, an independent and direct way to measure tau neutrino production following high energy proton interactions was proposed. As the main source of tau neutrinos is a decay of Ds mesons, produced in proton-nucleus interactions, the project aims at measuring a differential cross section of this reaction. The experimental method is based on a use of high resolution emulsion detectors for effective registration of events with short lived particle decays. Here we present the motivation of the study, details of the experimental technique, and the first results of the analysis of the data collected during test runs, which prove feasibility of the full scale study of the process in future

Status of vertex and tracking detector R&D at CLIC

The physics aims at the future CLIC high-energy linear e+e- collider set very high precision requirements on the performance of the vertex and tracking detectors. Moreover, these detectors have to be well adapted to the experimental conditions, such as the bunch train structure of the beam and the presence of beam-induced backgrounds. The principal challenges are: a point resolution of a few micron, ultra-low mass (~0.2% X0 per layer for the inner vertex region), very low power dissipation (compatible with air-flow cooling in the inner vertex region) and pulsed power operation, complemented with ~10 ns time stamping capabilities. An overview of the R&D program for pixel and tracking detectors at CLIC will be presented, including recent results on an innovative hybridisation concept based on capacitive coupling between active sensors (HV-CMOS) and readout ASICs (CLICpix)

An outlook to centrality dependence of event-by-event fluctuations of maximum pseudo-rapidity gap

A detailed study of centrality dependence of event-by-event fluctuations of maximum pseudo-rapidity gap of the produced particles has been carried out in terms of the scaled variance ω for 22Ne-emulsion interactions at 4.1 AGeV/c and 28Si-emulsion interactions at 4.5 AGeV/c. Depending on the values of the total charges or sum of the charges of non interacting projectile fragments, event samples were classified into three different centrality classes. Presence of centrality dependence of event-by-event fluctuations of maximum pseudo-rapidity gap is reflected in the multiparticle production process from this analysis. The event-by-event fluctuations are found to increase with decreasing centrality of collisions. Experimental analysis has been compared with the results obtained from the analysis of Monte Carlo simulated (MC-RAND) events in order to extract dynamical fluctuations. The difference between the experimental and simulated values of event-by-event fluctuations establishes the existence of true dynamical correlation among the produced particles