Difference between revisions of "Abstracts"
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experiments, allow measurements of the decay rate and of possible CP | experiments, allow measurements of the decay rate and of possible CP | ||
violation in this decay with per cent precision. | violation in this decay with per cent precision. | ||
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| + | The NA62 RICH detector | ||
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| + | The CERN NA62 experiment aims at a 10% measurement of the BR of the K+ into a pi+ and two neutrinos. The main background is the K+ decay into a muon and a neutrino, so pion-muon separation is a crucial ingredient. The RICH detector must separate pions from muons at 3 sigma level between 15 and 35 GeV/c momentum. The RICH must also measure the pion crossing time with a 100 ps resolution to avoid fake coincidences with an upstream beam spectrometer. To fufill these requirements a RICH filled with Neon at atmospheric pressure has been chosen, with a radiator length of 17 m. A mosaic of 20 hexagonal or semi-hexagonal mirrors with 17 m focal length, placed at the downstream end of the detector, will reflect the Cherenkov light onto two spots (to avoid the shadow induced by a beam pipe crossing the detector) located at the upstream end of the RICH where 2000 photomultipliers in total will be placed. Single anode photomultipliers, put at 18 mm minimum distance among each other have been chosen to match the required time resolution and Cherenkov angle sensitivity. A prototype was built to validate the project, with the same longitudinal dimensions (17 m) but reduced transverse size with respect to the final detector. In 2007 the prototype, equipped with 96 photomultipliers and exposed to a pion beam at CERN, showed a time resolution smaller than 100 ps. In 2009 in another test beam the prototype was equipped with 414 photomultipliers and demonstrated the capability to suppress by a factor 100 the muon background with respect to charged pions in a 15-35 GeV/c momentum range. The detector, approved and fully financed, is now in its construction phase with commissioning foreseen in 2012. The details of the project and the results of the test beams will be discussed. | ||
== Abstracts 2009 == | == Abstracts 2009 == | ||
Revision as of 22:29, 10 February 2010
Abstracts 2010
Measurement of BR(K --> e nu)/BR(K --> mu nu)
Measurement of the helicity suppressed ratio of charged kaon leptonic decay rates BR(K --> e nu)/BR(K --> mu nu) has long been considered as an excellent test of lepton universality and the Standard Model (SM) description of weak interactions. It was realised recently that the suppression of the SM contribution might enhance the sensitivity to SUSY-induced effects to an experimentally accessible level. The NA62 experiment at the CERN SPS has collected a record number of over 105 K --> e nu decays during a dedicated run in 2007, aiming at achieving 0.5% precision. Experimental strategy, details of the analysis and preliminary results are discussed.
Measurement of the FCNC Decays K+- -> pi+- l+ l-
We report on measurements of the rare decays K+- -> pi+- e+ e- and K+- -> pi+- mu+ mu-. The full NA48/2 data set was analyzed, leading to more than 7200 reconstructed events in the electronic and more than 3000 events in the muonic channel, the latter exceeding the total existing statistics by a factor of five. For both channels the selected events are almost background-free. From these events, we have determined the branching fraction and form factors of K+- -> pi+- e+ e- using different theoretical models. Our results improve the existing world averages significantly. In addition, we measured the CP violating asymmetry between K+ and K- in this channel to be less than a few percent.
Measurement of Ks --> pipiee decay mode
The Ks to pipiee decay mode has been investigated using the data collected in 2002 by the NA48/1 collaboration. With about 23k signal events and 59k KL to pi+ pi- pi0D normalization decays, the ks to pipiee branching ratio was determined with respect to the KL one. This result is also used to set an upper limit on the presence of E1 direct emission in the decay amplitude. The CP-violating asymmetry has been also measured.
Precision Measurement of pi pi Scattering Lengths in Ke4 Decays
The measurement of the S-wave pi pi scattering lengths is a fundamental test of the validity of Chiral Perturbation Theory. We report on the final NA48/2 result, which uses the complete NA48/2 data set with more than a million reconstructed K+-e4 decays. From these events we have determined the decay form factors and pi pi scattering lengths a0_0 and a2_0. The result is the most precise measurement of the scattering lengths and in excellent agreement with the prediction of Chiral Perturbation Theory.
Precision Measurement of Photon Emission in K+- -> pi+- pi0 gamma Decays
We report our final result on the measurement of direct photon emission (DE) in the decay K+- -> pi+- pi0 gamma and its interference (INT) with the inner bremsstrahlung amplitude. For this measurement the full NA48/2 data set with about 600k reconstructed K+- -> pi+- pi0 gamma decays was analyzed, which is factor of 30 larger than for previous experiments and a factor of three w.r.t. our preliminary result. From this, the sizes of both the DE and the INT amplitudes have been measured with high precision, with the INT amplitude being observed for the first time. In addition, the CP violating asymmetry between K+ and K- has been obtained to be less than 103 in this channel.
Measurement of the rare Decay K+- -> pi+- gamma gamma
We report on the measurement of the branching fraction of the rare decay K+- -> pi+- gamma gamma using the full NA48/2 dataset of more than 5000 reconstructed decays from the full NA48/2 data set. From the spectrum of the invariant gamma gamma mass, the decay parameter c^ can be extracted with unprecedented precision.
Measurement of the radiative Decay K+- -> pi0 e+- nu_e gamma (Ke3gamma)
We report on the measurement of more than 200000 events of the decay K+- -> pi0 e+- nu_e gamma, recorded with the NA48/2 detector at CERN. These statistics, about two orders of magnitude more than previous experiments, allow measurements of the decay rate and of possible CP violation in this decay with per cent precision.
The NA62 RICH detector
The CERN NA62 experiment aims at a 10% measurement of the BR of the K+ into a pi+ and two neutrinos. The main background is the K+ decay into a muon and a neutrino, so pion-muon separation is a crucial ingredient. The RICH detector must separate pions from muons at 3 sigma level between 15 and 35 GeV/c momentum. The RICH must also measure the pion crossing time with a 100 ps resolution to avoid fake coincidences with an upstream beam spectrometer. To fufill these requirements a RICH filled with Neon at atmospheric pressure has been chosen, with a radiator length of 17 m. A mosaic of 20 hexagonal or semi-hexagonal mirrors with 17 m focal length, placed at the downstream end of the detector, will reflect the Cherenkov light onto two spots (to avoid the shadow induced by a beam pipe crossing the detector) located at the upstream end of the RICH where 2000 photomultipliers in total will be placed. Single anode photomultipliers, put at 18 mm minimum distance among each other have been chosen to match the required time resolution and Cherenkov angle sensitivity. A prototype was built to validate the project, with the same longitudinal dimensions (17 m) but reduced transverse size with respect to the final detector. In 2007 the prototype, equipped with 96 photomultipliers and exposed to a pion beam at CERN, showed a time resolution smaller than 100 ps. In 2009 in another test beam the prototype was equipped with 414 photomultipliers and demonstrated the capability to suppress by a factor 100 the muon background with respect to charged pions in a 15-35 GeV/c momentum range. The detector, approved and fully financed, is now in its construction phase with commissioning foreseen in 2012. The details of the project and the results of the test beams will be discussed.
Abstracts 2009
Excited QCD
Tests of Chiral Perturbation Theory with Ke4 decays at NA48
Precision measurement of photon emission in K+- -> pi+- pi0 gamma decays
Moriond QCD
Precision measurement of photon emission in K+- -> pi+- pi0 gamma decays
Measurement of the FCNC decays K+- -> pi+- l+ l-
TIPP09
The Trigger System for the NA62 experiment at the CERN SPS
The Photon Veto System for the NA62 Rare Kaon Decay Experiment
Pixel Read-Out Architectures for the NA62 Gigatracker
Usage of Silicon PhotoMultipliers for the CEDAR ...
Animma
The Trigger System for the NA62 experiment at the CERN SPS
The Photon Veto System for the NA62 Rare Kaon Decay Experiment
Pixel Read-Out Architectures for the NA62 Gigatracker
Usage of Silicon PhotoMultipliers for the CEDAR ...
GHP2009
CIPANP
Search of New Physics with Kaon decays at NA62
Blois
Search of New Physics with Kaon decays at NA62
PASCOS2009
Search of New Physics with Kaon decays at NA62
Lomonosov
