The NA62 Experiment at CERN

The main physics goal of the NA62 experiment at CERN is to precisely measure the branching ratio of the kaon rare decay $K^+\rightarrow \pi^+ \nu \bar\nu$. This decay is strongly suppressed in the Standard Model and its branching ratio is theoretically calculated with high accuracy. The NA62 experiment is designed to measure this decay rate with an uncertainty better than 10\%. The measurement can be a good probe of new physics phenomena, which can alter the SM decay rate. The NA62 experiment has been successfully launched in October 2014. In this document, after an introduction to the theoretical framework, the NA62 experimental setup is described and a first look at the pilot run data is reported

Prospects for an experiment to measure BR(KL→π0ννˉ)BR(K_L\rightarrow \pi^0\nu\bar\nu) at the CERN SpS

We are investigating the feasibility of performing a measurement of $BR(K_L\rightarrow\pi^0\nu\bar\nu)$ using a high-energy secondary neutral beam at the CERN SPS in a successor experiment to NA62. The timescale would require many years; we assume that the experiment would be ready at the start of LHC Run 4. Some preliminary conclusions from our feasibility studies, design challenges faced and sensitivity obtainable for the measurement are here presented

Study of the performance of the LHCb MWPC with cosmic rays

In this note we report the results of measurements performed with cosmic rays on different LHCb Muon Chambers. The main characteristics of the chambers have been investigated as a function of the high voltage value in order to achieve a better comprehension of the detector performance both for optimizing the chamber working conditions on the experimental apparatus and for providing useful information for the Monte Carlo simulation

Stochastic processes and applications to countably additive restrictions of group-valued finitely additive measures

As an application of a theorem concerning a general stochastic process in a finitely additive probability space, the existence of non-atomic countably additive restrictions with large range is obtained for group-valued finitely additive measures

A new method based on noise counting to monitor the frontend electronics of the LHCb muon detector

A new method has been developed to check the correct behaviour of the frontend electronics of the LHCb muon detector. This method is based on the measurement of the electronic noise rate at different thresholds of the frontend discriminator. The method was used to choose the optimal discriminator thresholds. A procedure based on this method was implemented in the detector control system and allowed the detection of a small percentage of frontend channels which had deteriorated. A Monte Carlo simulation has been performed to check the validity of the method

Dependence of the energy resolution of a scintillating crystal on the readout integration time

The possibilty of performing high-rate calorimetry with a slow scintillating crystal is studied. In this experimental situation, to avoid pulse pile-up, it can be necessary to base the energy measurement on only a fraction of the emitted light, thus spoiling the energy resolution. This effect was experimentally studied with a BGO crystal and a photomultiplier followed by an integrator, by measuring the maximum amplitude of the signals. The experimental data show that the energy resolution is exclusively due to the statistical fluctuations of the number of photoelectrons contributing to the maximum amplitude. When such number is small its fluctuations are even smaller than those predicted by Poisson statistics. These results were confirmed by a Monte Carlo simulation which allows to estimate, in a general case, the energy resolution, given the total number of photoelectrons, the scintillation time and the integration time

Performance of the LHCb muon system with cosmic rays

The LHCb Muon system performance is presented using cosmic ray events collected in 2009. These events allowed to test and optimize the detector configuration before the LHC start. The space and time alignment and the measurement of chamber efficiency, time resolution and cluster size are described in detail. The results are in agreement with the expected detector performance.Comment: Submitted to JINST and accepte

Measurement of the front-end dead-time of the LHCb muon detector and evaluation of its contribution to the muon detection inefficiency

A method is described which allows to deduce the dead-time of the front-end electronics of the LHCb muon detector from a series of measurements performed at different luminosities at a bunch-crossing rate of 20 MHz. The measured values of the dead-time range from 70 ns to 100 ns. These results allow to estimate the performance of the muon detector at the future bunch-crossing rate of 40 MHz and at higher luminosity