Measuring the masses of the charged hadrons using a RICH as a precision velocity spectrometer

The Selex experiment measured several billion charged hadron tracks with a high precision magnetic momentum spectrometer and high precision RICH velocity spectrometer. We have analyzed these data to simultaneously measure the masses of all the long lived charged hadrons and anti-hadrons from the pi to the Omega using the same detector and technique. The statistical precision achievable with this data sample is more than adequate for 0.1% mass measurements We have used these measurements to develop and understand the systematic effects of a RICH as a precision velocity spectrometer with the goal of measuring 10 masses with precision ranging from 100 KeV for the lightest to 1000 KeV for the heaviest. This requires controlling the radius measurement of RICH rings to the ~10^{-4} level. Progress in the mass measurements and the required RICH analysis techniques developed are discussed.Comment: Submitted to special edition of NIMA, Proceedings of RICh2010. v2 as accepted for publicatio

Cherenkov Light Imaging - Fundamentals and recent Developments

We review in a historical way the fundamentals of Cherenkov light imaging applied to Ring Imaging Cherenkov Counters. We also point out some of the newer developments in this very active field.Comment: Submitted to special edition of NIMA, Proceedings of RICH201

Review of Kaon Physics at CERN and in Europe

The Kaon physics program at CERN and in Europe will be presented. I will first give a short review of recent results form the NA48/2 and NA62 experiments, with special emphasis to the measurement of RK , the ratio of Kaon leptonic decays rates, K → eν and K → μν, using the full minimum bias data sample collected in 2007-2008. The main subject of the talk will be the study of the highly suppressed decay K → πνν. While its rate can be predicted with minimal theoretical uncertainty in the Standard Model (BR ∼ 8 × 10−11), the smallness of BR and the challenging experimental signature make it very difficult to measure. The branching ratio for this decay is thus a sensitive probe of the flavour sector of the SM. The aim of NA62 is the measurement of the K → πνν BR with ∼ 10% precision in two years of data taking. This will require the observation of 10K decays in the experiment's fiducial volume, as well as the use of high-performance systems for precision tracking, particle identification, and photon vetoing. These aspects of the experiment will also allow NA62 to carry out a rich program of searches for lepton flavour and/or number violating K decays. Data taking will start in October 2014. The physics prospects and the status of the construction and commissioning of the NA62 experiment will be presented. In the last part of the talk I will report on Kaon physics results and prospects from other experiments at CERN (e.g. LHCb) and in Europe (e.g. KLOE and KLOE-2) and briefly mention the status in US

A Method to Evaluate Mirrors for Cherenkov Counters

A method is evaluated for measuring mirrors to be used in a Ring Imaging Cherenkov Counter. It was first used to evaluate astronomical quality mirrors, but has been found to be applicable for the lower surface quality of Cherenkov mirrors. 1 Introduction The authors are building a Ring Imaging Cherenkov Counter to identify particle types in charmed baryon decays in Fermilab experiment E781 (SELEX) [1]. The Cherenkov light will be focussed by an array of 16 hexagonally-shaped spherical mirrors (20 m radius of curvature) onto a photocathode that consists of 2848 phototubes of 15 mm diameter. A design goal for the mirrors is that they do not contribute significantly to the error on reconstructed Cherenkov ring radii. This translates to an RMS width of about 5 cm ( 1 4 %) for both the variation in radius of curvature across a single mirror as well as the variation from mirror to mirror of the average radius of curvature. This criterion is much below that needed for astronomical mirrors. ..