We present an analysis of the decay D 0 → K + π − based on FOCUS data. From a sample of 234 signa... more We present an analysis of the decay D 0 → K + π − based on FOCUS data. From a sample of 234 signal events, we find a branching ratio of Γ(D 0 →K + π −) Γ(D 0 →K − π +) = (0.429 + 0.063 − 0.061 ± 0.027)% under the assumptions of no mixing and no CP violation. Allowing for CP violation, we find a branching ratio of (0.429 ± 0.063 ± 0.028)% and a CP asymmetry of 0.18 ± 0.14 ± 0.04. The branching ratio for the case of mixing with no CP violation is (0.381 + 0.167 − 0.163 ± 0.092)%. We also present limits on charm mixing.
The absolute branching fractions for the decays D À s ! ' À " ' (' ¼ e, , or) are measured using ... more The absolute branching fractions for the decays D À s ! ' À " ' (' ¼ e, , or) are measured using a data sample corresponding to an integrated luminosity of 521 fb À1 collected at center-of-mass energies near 10.58 GeV with the BABAR detector at the PEP-II e þ e À collider at SLAC. The number of D À s mesons is determined by reconstructing the recoiling system DKX in events of the type e þ e À ! DKXD ÃÀ s , where
Amplitude analysis and branching-fraction measurement of D + s → K 0 S π + π 0 The BESIII collabo... more Amplitude analysis and branching-fraction measurement of D + s → K 0 S π + π 0 The BESIII collaboration
The NA62 experiment reports the branching ratio measurement $$ \mathrm{BR}\left({K}^{+}\to {\pi}^... more The NA62 experiment reports the branching ratio measurement $$ \mathrm{BR}\left({K}^{+}\to {\pi}^{+}\nu \overline{\nu}\right)=\left({10.6}_{-3.4}^{+4.0}\left|{}_{\mathrm{stat}}\right.\pm {0.9}_{\mathrm{syst}}\right)\times {10}^{-11} $$ BR K + → π + ν ν ¯ = 10.6 − 3.4 + 4.0 stat ± 0.9 syst × 10 − 11 at 68% CL, based on the observation of 20 signal candidates with an expected background of 7.0 events from the total data sample collected at the CERN SPS during 2016–2018. This provides evidence for the very rare K+→$$ {\pi}^{+}\nu \overline{\nu} $$ π + ν ν ¯ decay, observed with a significance of 3.4σ. The experiment achieves a single event sensitivity of (0.839 ± 0.054) × 10−11, corresponding to 10.0 events assuming the Standard Model branching ratio of (8.4 ± 1.0) × 10−11. This measurement is also used to set limits on BR(K+→ π+X), where X is a scalar or pseudo-scalar particle. Details are given of the analysis of the 2018 data sample, which corresponds to about 80% of the total data ...
using a data sample collected in 2017. No signals are observed, and upper limits on the branching... more using a data sample collected in 2017. No signals are observed, and upper limits on the branching fractions of these decays of 2.2 × 10 −10 and 4.2 × 10 −11 are obtained, respectively, at 90% confidence level. These upper limits improve on previously reported measurements by factors of 3 and 2, respectively.
The results of a search for π 0 decays to a photon and an invisible massive dark photon at the NA... more The results of a search for π 0 decays to a photon and an invisible massive dark photon at the NA62 experiment at the CERN SPS are reported. From a total of 4.12 × 108 tagged π 0 mesons, no signal is observed. Assuming a kinetic-mixing interaction, limits are set on the dark photon coupling to the ordinary photon as a function of the dark photon mass, improving on previous searches in the mass range 60–110 MeV/c 2. The present results are interpreted in terms of an upper limit of the branching ratio of the electro-weak decay $$ {\pi}^0\to \gamma \nu \overline{\nu} $$ π 0 → γ ν ν ¯ , improving the current limit by more than three orders of magnitude.
We present an analysis of the decay D 0 → K + π − based on FOCUS data. From a sample of 234 signa... more We present an analysis of the decay D 0 → K + π − based on FOCUS data. From a sample of 234 signal events, we find a branching ratio of Γ(D 0 →K + π −) Γ(D 0 →K − π +) = (0.429 + 0.063 − 0.061 ± 0.027)% under the assumptions of no mixing and no CP violation. Allowing for CP violation, we find a branching ratio of (0.429 ± 0.063 ± 0.028)% and a CP asymmetry of 0.18 ± 0.14 ± 0.04. The branching ratio for the case of mixing with no CP violation is (0.381 + 0.167 − 0.163 ± 0.092)%. We also present limits on charm mixing.
The absolute branching fractions for the decays D À s ! ' À " ' (' ¼ e, , or) are measured using ... more The absolute branching fractions for the decays D À s ! ' À " ' (' ¼ e, , or) are measured using a data sample corresponding to an integrated luminosity of 521 fb À1 collected at center-of-mass energies near 10.58 GeV with the BABAR detector at the PEP-II e þ e À collider at SLAC. The number of D À s mesons is determined by reconstructing the recoiling system DKX in events of the type e þ e À ! DKXD ÃÀ s , where
Amplitude analysis and branching-fraction measurement of D + s → K 0 S π + π 0 The BESIII collabo... more Amplitude analysis and branching-fraction measurement of D + s → K 0 S π + π 0 The BESIII collaboration
The NA62 experiment reports the branching ratio measurement $$ \mathrm{BR}\left({K}^{+}\to {\pi}^... more The NA62 experiment reports the branching ratio measurement $$ \mathrm{BR}\left({K}^{+}\to {\pi}^{+}\nu \overline{\nu}\right)=\left({10.6}_{-3.4}^{+4.0}\left|{}_{\mathrm{stat}}\right.\pm {0.9}_{\mathrm{syst}}\right)\times {10}^{-11} $$ BR K + → π + ν ν ¯ = 10.6 − 3.4 + 4.0 stat ± 0.9 syst × 10 − 11 at 68% CL, based on the observation of 20 signal candidates with an expected background of 7.0 events from the total data sample collected at the CERN SPS during 2016–2018. This provides evidence for the very rare K+→$$ {\pi}^{+}\nu \overline{\nu} $$ π + ν ν ¯ decay, observed with a significance of 3.4σ. The experiment achieves a single event sensitivity of (0.839 ± 0.054) × 10−11, corresponding to 10.0 events assuming the Standard Model branching ratio of (8.4 ± 1.0) × 10−11. This measurement is also used to set limits on BR(K+→ π+X), where X is a scalar or pseudo-scalar particle. Details are given of the analysis of the 2018 data sample, which corresponds to about 80% of the total data ...
using a data sample collected in 2017. No signals are observed, and upper limits on the branching... more using a data sample collected in 2017. No signals are observed, and upper limits on the branching fractions of these decays of 2.2 × 10 −10 and 4.2 × 10 −11 are obtained, respectively, at 90% confidence level. These upper limits improve on previously reported measurements by factors of 3 and 2, respectively.
The results of a search for π 0 decays to a photon and an invisible massive dark photon at the NA... more The results of a search for π 0 decays to a photon and an invisible massive dark photon at the NA62 experiment at the CERN SPS are reported. From a total of 4.12 × 108 tagged π 0 mesons, no signal is observed. Assuming a kinetic-mixing interaction, limits are set on the dark photon coupling to the ordinary photon as a function of the dark photon mass, improving on previous searches in the mass range 60–110 MeV/c 2. The present results are interpreted in terms of an upper limit of the branching ratio of the electro-weak decay $$ {\pi}^0\to \gamma \nu \overline{\nu} $$ π 0 → γ ν ν ¯ , improving the current limit by more than three orders of magnitude.
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Papers by R. Aliberti