Gigatracker is in the core of one of the spectrometers used in NA62. It's composed of three planes of silicon pixels detectors assembled in a traditional way: readout electronics bump bonded on silicon sensors. Each plane is composed by 18000 pixels 300 um x 300 um arranged in 45 columns and readout by 10 chips. The particularity of this sensor is that its timing resolution should be better than 200 ps in order to cope with high expected rate (800 MHz). Another particularity is its operation in vacuum. CP3 is involved in several aspects in the construction of this detector. 1) Signal development of the signal in the sensor. We use both commercial programs (i.e. TCAD by Synopsys) as well as software developed by us to study the expected signal of this sensor. This step is of high importance to design and scale properly the readout electronics readout. 2) Design and test of the readout chip. We are participation in the design of one of the two proposed chips to perform the sensor readout, the so called End-Of-Column option. We will participate also in the test both at lab as well as under beam of this chip. This work is being done in collaboration with CERN and INFN (Torino). 3) Support mechanics and cooling. CP3 is one of the responsible institutes in the design, construction and assembly of the support mechamics and cooling. The whole system should be light, able to operate in vacuum as well as assure a thermal stability. This work is done in collaboration with INFN (Ferrara) A campaign of test beams has been scheduled in order to fully qualify this detector.
ALthough the study of rare kaon radiative decays is not the main objective of NA62, both the detector and the beam are fully adapted to their study. Among all radiative kaon decays, two channels are going to be studied in depth in order to see if NA62 could provide extra information: and . These channels can provide information about direct CP violation and QCD-QED interplay.
External collaborators: A. Ceccucci (CERN).
A precision test of lepton flavour universality can be performed by measuring the ratio RK of kaon leptonic decay rates and . Any deviation of the expected Standard Model prediction will be a hint of New Physics. This measurement has been performed at one percent level with the NA62 data taken in 2007 and 2008 in complete agreement with the Standard Model expectation. A prospective analysis for the improvement of this measurement with the full NA62 apparatus is underway.
External collaborators: Augusto Ceccucci (CERN), Cristina Lazzeroni (Birmingham).
