1,196 research outputs found
results from NA48 and KTeV E832
No full textAfter more than 25 years of intense experimental effort, the parameter which characterizes direct CP violation in the neutral kaon system has been accurately measured by both the Fermilab KTeV E832 and the Cern NA48 experiments. The latest results presented here demonstrate unambiguosly the existence of direct CP violation. The experimental challenge is reviewed, and the techniques used to extract the parameter are discussed. The current situation is given and future propects are briefly sketched
Results on CP violation from NA48
No full textThe main goal of the NA48 experiment at the CERN SPS accelerator is the measurement of the direct CP violation parameter in the decays, with an accuracy close to . The preliminary result obtained from 1998 data is reviewed. The use of intense and beams allows in parallel the investigation of rare CP violating decays. The future project aiming to study direct CP violation with charged kaon beams is briefly discussed
Détermination précise des fonctions de structure du nucléon dans les interactions de type courant-chargé de neutrinos sur cible de fer
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A new measurement of structure functions from charged-current (anti)neutrino interactions on iron
No full textSearches for lepton number violation and resonances in K± → πμμ decays
No full textThe NA48/2 experiment at CERN collected a large sample of charged kaon decays to final states with multiple charged particles in 2003–2004. A new upper limit on the rate of the lepton number violating decay K±→π∓μ±μ± is reported: B(K±→π∓μ±μ±)<8.6×10−11 at 90% CL. Searches for two-body resonances X in K±→πμμ decays (such as heavy neutral leptons N4 and inflatons χ) are also presented. In the absence of signals, upper limits are set on the products of branching fractions B(K±→μ±N4)B(N4→πμ) and B(K±→π±X)B(X→μ+μ−) for ranges of assumed resonance masses and lifetimes. The limits are in the (10−11,10−9) range for resonance lifetimes below 100 ps. © 2017 The Author(s
Observation of charmless hadronic b decays
No full textFour candidates for charmless hadronic B decay are observed in a data sample of four million hadronic Z decays recorded by the aleph detector at lep. The probability that these events come from background sources is estimated to be less than 10−6. The average branching ratio of weakly decaying B hadrons (a mixture of Bd0, Bs0 and Λb weighted by their production cross sections and lifetimes, here denoted B) into two long-lived charged hadrons (pions, kaons or protons) is measured to be Br(B → h+h−) = (1.7−0.7+1.0 ± 0.2) × 10−5. The relative branching fraction is measured to be 1.0−0.3 −0.1+0.0 +0.0. In addition, branching ratio upper limits are obtained for a variety of exclusive charmless hadronic two-body decays of B hadrons
Measurements of the b baryon lifetime
No full textUsing about 1.5 million hadronic Z decays recorded with the aleph detector, the lifetime of the b baryons has been measured using two independent data samples. From a maximum likelihood fit to the impact parameter distribution of leptons in 519 Λℓ− combinations containing a b baryon sample of 290 decays, the measured b baryon lifetime is τb—baryon = 1.05−0.11+0.12(stat)±0.09(syst) ps. The lifetime of the Λb0 baryon from a maximum likelihood fit to the proper time distribution of 58 Λc+ℓ− candidates containing a Λb0 sample of 44 decays, is τΛb0 = 1.02−0.18+0.23(stat) ± 0.06(syst) ps
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