Search for Lepton Number and Flavor Violation in K^{+} and π^{0} Decays

Searches for the lepton number violating K^{+}→π^{-}μ^{+}e^{+} decay and the lepton flavor violating K^{+}→π^{+}μ^{-}e^{+} and π^{0}→μ^{-}e^{+} decays are reported using data collected by the NA62 experiment at CERN in 2017-2018. No evidence for these decays is found and upper limits of the branching ratios are obtained at 90% confidence level: B(K^{+}→π^{-}μ^{+}e^{+})<4.2×10^{-11}, B(K^{+}→π^{+}μ^{-}e^{+})<6.6×10^{-11} and B(π^{0}→μ^{-}e^{+})<3.2×10^{-10}. These results improve by 1 order of magnitude over previous results for these decay modes.

NA62 and NA48/2 results on search for Heavy Neutral Leptons

In this paper we present new results on upper limits for the search of Heavy Neutral Leptons (HNL) with data collected by NA48/2 (2003-2004), NA62-RK (2007) and NA62 (2015) CERN experiments. The data collected with different trigger configuration allow to search for both long and short living heavy neutrinos in the mass range below the kaon mass. In addition the status of the search for K+ → π+vv with the NA62 detector will be briefly presented.

[An absent correlation between antioxidant blood concentrations and the remission response of preoperatively treated breast carcinomas]

PURPOSE

Deleterious effects of ionizing radiation and some chemotherapeutic agents are predominantly caused by reactive oxygen agents which are detoxified by antioxidants. This study was designed to evaluate the modifying effects of vitamin A-, vitamin E- and selenium serum concentrations and glutathione peroxidase activity on preoperative radio- and chemotherapy of breast cancer.

PATIENTS AND METHODS

Tumor volume, vitamin A-, vitamin E-, selenium serum concentrations and glutathione peroxidase activity in circulating erythrocytes were determined in 40 patients with breast cancer before treatment. Interstitial radiohyperthermia was given initially using a single dose of 10 Gy (HDR) combined with hyperthermia between 43.5 to 44.5 degrees C over 60 minutes followed by external beam radiotherapy with 50 Gy in 5 weeks. All patients received anthracyline or anthrachinone containing chemotherapy. Tumor response was determined by histopathological examination. Patients with complete and incomplete remissions were compared using the Wilcoxon test. Pre- and posttreatment tumor-volume differences were correlated with antioxidant concentrations (Spearman correlation coefficient).

RESULTS

Twenty patients (50%) achieved a complete histopathologic tumor regression. This high complete remission rate was not related to the antioxidants under investigation (vitamin A: p = 0.32, vitamin E: p = 0.44, selenium: p = 0.68, glutathione peroxidase: p = 0.3). There was no correlation to pre- and posttreatment tumor-volume-differences either (vitamin A: p = 0.89, vitamin E: p = 0.67, selenium: p = 0.41, glutathione peroxidase: p = 0.87).

CONCLUSIONS

In this study serum concentrations of antioxidants had no modifying influence on tumor response in breast cancer patients following induction radio-chemotherapy and subsequent surgery. Further studies measuring tissue levels could clarify if there is any modifying influence of antioxidants on tumor remission.