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Bernlochner, F. (ORCID:0000000181532719)

Publications and source records attributed to Bernlochner, F. (ORCID:0000000181532719).

12 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Averages of 𝑏-hadron, 𝑐-hadron, and 𝜏-lepton properties as of 2023

This paper reports world averages of measurements of 𝑏-hadron, 𝑐-hadron, and 𝜏-lepton properties obtained by the Heavy Flavor Averaging Group using results available before October 2023. In rare cases, significant results obtained several months later are also used. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, 𝐢⁒𝑃 violation parameters, parameters of semileptonic decays, and Cabibbo-Kobayashi-Maskawa matrix elements.

Bottom quark production↗
DOE OSTI2024

Measurement of Angular Coefficients of B Β― β†’ D * β„“ Ξ½ Β― β„“ : Implications for | V c b | and Tests of Lepton Flavor Universality

We measure the complete set of angular coefficients J i for exclusive B Β― β†’ D * β„“ Ξ½ Β― β„“ decays ( β„“ = e , ΞΌ ). Our analysis uses the full 711 fb βˆ’ 1 Belle dataset with hadronic tag-side reconstruction. The results allow us to extract the form factors describing the B Β― β†’ D * transition and the Cabibbo-Kobayashi-Maskawa matrix element | V cb | . Using recent lattice QCD calculations for the hadronic form factors, we find | V cb | = ( 40.7 Β± 0.7 ) Γ— 10 βˆ’ 3 using the Boyd-Grinstein-Lebed parametrization, compatible with determinations from inclusive semileptonic decays. We search for lepton flavor universality violation as a function of the hadronic recoil parameter w and investigate the differences of the electron and muon angular distributions. We find no deviation from standard model expectations. Published by the American Physical Society 2024

Physics↗
DOE OSTI2024

Measurement of the branching fractions of $$ \overline{B} $$ β†’ D(*)Kβˆ’$$ {K}_{(S)}^{\left(\ast \right)0} $$ and $$ \overline{B} $$ β†’ D(*)$$ {D}_s^{-} $$ decays at Belle II

Abstract We present measurements of the branching fractions of eight$$ {\overline{B}}^0 $$ B Β― 0 β†’D (*)+ K βˆ’ $$ {K}_{(S)}^{\left(\ast \right)0} $$ K S βˆ— 0 ,B βˆ’ β†’D (*)0 K βˆ’ $$ {K}_{(S)}^{\left(\ast \right)0} $$ K S βˆ— 0 decay channels. The results are based on data from SuperKEKB electron-positron collisions at the Ξ₯(4S) resonance collected with the Belle II detector, corresponding to an integrated luminosity of 362 fb βˆ’1 . The event yields are extracted from fits to the distributions of the difference between expected and observedBmeson energy, and are efficiency-corrected as a function ofm(K βˆ’ $$ {K}_{(S)}^{\left(\ast \right)0} $$ K S βˆ— 0 ) andm(D (*) $$ {K}_{(S)}^{\left(\ast \right)0} $$ K S βˆ— 0 ) in order to avoid dependence on the decay model. These results include the first observation of$$ {\overline{B}}^0 $$ B Β― 0 β†’D + K βˆ’ $$ {K}_S^0 $$ K S 0 ,B βˆ’ β†’D* 0 K βˆ’ $$ {K}_S^0 $$ K S 0 , and$$ {\overline{B}}^0 $$ B Β― 0 β†’D* + K βˆ’ $$ {K}_S^0 $$ K S 0 decays and a significant improvement in the precision of the other channels compared to previous measurements. The helicity-angle distributions and the invariant mass distributions of theK βˆ’ $$ {K}_{(S)}^{\left(\ast \right)0} $$ K S βˆ— 0 systems are compatible with quasi-two-body decays via a resonant transition with spin-parityJ P = 1 βˆ’ for theK βˆ’ $$ {K}_S^0 $$ K S 0 systems andJ P = 1 + for theK βˆ’ K* 0 systems. We also present measurements of the branching fractions of four$$ {\overline{B}}^0 $$ B Β― 0 β†’D (*)+ $$ {D}_s^{-} $$ D s βˆ’ ,B βˆ’ β†’D (*)0 $$ {D}_s^{-} $$ D s βˆ’ decay channels with a precision compatible to the current world averages.

Physics↗
DOE OSTI2024

Study of Ξ₯(10753) decays to Ο€+Ο€βˆ’Ξ₯(nS) final states at Belle II

Abstract We present an analysis of the processe + e βˆ’ β†’Ο€ + Ο€ βˆ’ Ξ₯(nS) (wheren= 1, 2, or 3) reconstructed in 19.6 fb βˆ’1 of Belle II data during a special run of the SuperKEKB collider at four energy points near the peak of the Ξ₯(10753) resonance. By analyzing the mass distribution of theΟ€ + Ο€ βˆ’ Ξ₯(nS) system and the Born cross sections of thee + e βˆ’ β†’Ο€ + Ο€ βˆ’ Ξ₯(nS) process, we report the first observation of Ξ₯(10753) decays to theΟ€ + Ο€ βˆ’ Ξ₯(1S) andΟ€ + Ο€ βˆ’ Ξ₯(2S) final states, and find no evidence for decays toΟ€ + Ο€ βˆ’ Ξ₯(3S). Possible intermediate states in theΟ€ + Ο€ βˆ’ Ξ₯(1S,2S) transitions are also investigated, and no evidence for decays proceeding via the$$ {\pi}^{\mp }{Z}_b^{\pm } $$ Ο€ βˆ“ Z b Β± orf 0 (980)Ξ₯(nS) intermediate states is found. We measure Born cross sections for thee + e βˆ’ β†’Ο€ + Ο€ βˆ’ Ξ₯(nS) process that, combined with results from Belle, obtain the mass and width of Ξ₯(10753) to be (10756.6 Β± 2.7 Β± 0.9) MeV/c 2 and (29.0 Β± 8.8 Β± 1.2) MeV, respectively. The relative ratios of the Born cross sections at the Ξ₯(10753) resonance peak are also reported for the first time.

Physics↗
DOE OSTI2023

First Simultaneous Determination of Inclusive and Exclusive | V u b |

The first simultaneous determination of the absolute value of the Cabibbo-Kobayashi-Maskawa matrix element V ub using inclusive and exclusive decays is performed with the full Belle data set at the $Ξ₯$(4S) resonance, corresponding to an integrated luminosity of 711 fb -1 . We analyze collision events in which one B meson is fully reconstructed in hadronic modes. This allows for the reconstruction of the hadronic X u system of the semileptonic b β†’ $Ο€β„“e_β„“$ decay. We separate exclusive B β†’ $Ο€β„“\overline{Ξ½}_β„“$ decays from other inclusive B β†’ $X_uβ„“\overline{Ξ½}_β„“$ and backgrounds with a two-dimensional fit that utilizes the number of charged pions in the X u system and the four-momentum transfer q 2 between the B and X u systems. Combining our measurement with information from lattice QCD and QCD calculations of the inclusive partial rate as well as external experimental information on the shape of the B β†’ $Ο€β„“e_β„“$ form factor, we determine |$V^{excl}_{ub}$| = (3.78 Β± 0.23 Β± 0.16 Β± 0.14) Γ— 10 -3 and |$V^{incl}_{ub}$| = (3.88 Β± 0.20 Β± 0.31 Β± 0.09) x 10 -3 , respectively, with the uncertainties being the statistical error, systematic errors, and theory errors. The ratio of |$V^{excl}_{ub}$|/|$V^{incl}_{ub}$| 0.97 Β± 0.12 is compatible with unity.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Evidence for B 0 β†’ p Ξ£ Β― 0 Ο€ - at Belle

We search for the B 0 β†’ p$\overline{Ξ£}$ 0 Ο€ - decay with $\overline{Ξ£}$ 0 β†’ $\overline{Ξ›}$ Ξ³, where the Ξ³ is not measured, using a data sample corresponding to an integrated luminosity of 711 fb -1 which contains 772 Γ— 10 6 B$\overline{B}$ pairs, collected around the Ξ₯(4S) resonance with the Belle detector at the KEKB asymmetric-energy e + e - collider. We measure for the first time the B 0 β†’ p$\overline{Ξ£}$ 0 Ο€ - branching fraction to be $\mathscr{B}$(B 0 β†’ p$\overline{Ξ£}$ 0 Ο€ - ) = $({1.17}_{-0.40}^{+0.43} (stat) Β± 0.07(syst))$ X 10 -6 with a significance of 3.0Οƒ. We simultaneously measure the branching fraction for the related channel B 0 β†’ p$\overline{Ξ›}$ Ο€ - with much improved precision.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Measurement of the e + e - β†’ $ {B}_s^0{\overline{B}}_s^0X $ cross section in the energy range from 10.63 to 11.02 GeV using inclusive $ {D}_s^{+} $ and D 0 production

We report the first measurement of the inclusive e + e - β†’ $b\bar{b}$ β†’ D$^Β±_s$ X and e + e - β†’ $b\bar{b}$ β†’ D 0 / $\overline{D}^0$ X cross sections in the energy range from 10.63 to 11.02 GeV. Based on these results, we determine Οƒ(e + e - β†’ ${B}_s^0{\overline{B}}_s^0$ X) and Οƒ(e + e - β†’ $B\overline{B}$ X) in the same energy range. We measure the fraction of ${B}_s^0$ events at Ξ₯(10860) to be f s = (${22.0}_{-2.1}^{+2.0}$)%. We determine also the ratio of the ${B}_s^0$ inclusive branching fractions $\mathcal{B}$(${B}_s^0$ β†’ D 0 / $\overline{D}^0$X)/$\mathcal{B}$(${B}_s^0$ β†’ ${D}_s^{\pm }$X) = 0.416 Β± 0.018 Β± 0.092. The results are obtained using the data collected with the Belle detector at the KEKB asymmetric-energy e + e - collider.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Measurement of differential distributions of B β†’ D*$\ell\bar{v}_{\ell}$ and implications on | V cb |

We present a measurement of the differential shapes of exclusive B β†’ D*$\ell\bar{v}_{\ell}$ (B = B - , $\bar{B}$ 0 and $\ell$ = e, ΞΌ) decays with hadronic tag-side reconstruction for the full 711 fb -1 Belle dataset. We extract the Caprini-Lellouch-Neubert (CLN) and Boyd-Grinstein-Lebed (BGL) form factor parameters and use an external input for the absolute branching fractions to determine the Cabibbo-Kobayashi-Maskawa matrix element and find |V cb | CLN = (40.2 Β± 0.9) x 10 -3 and |V cb | BGL = (40.7 Β± 1.0) x 10 -3 with the zero-recoil lattice QCD point $\mathcal{F}$(1) = 0.906 Β± 0.013. We also perform a study of the impact of beyond zero-recoil lattice QCD calculations on the |V cb | determinations. Additionally, we present the lepton-flavor universality ratio R eΞΌ = $\mathcal{B}$(B β†’ D*e$\bar{v}$ e )/$\mathcal{B}$(B β†’ D*ΞΌ$\bar{v}$ ΞΌ ) = 0.993 Β± 0.023 Β± 0.023, the electron and muon forwardbackward asymmetry and their difference Ξ”A FB = 0.028 Β± 0.028 Β± 0.008, and the electron and muon D* longitudinal polarization fraction and their difference Ξ”F$^{D*}_L$ = 0.030 Β± 0.025 Β± 0.007. The uncertainties quoted correspond to the statistical and systematic uncertainties, respectively.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

First observation of B β†’ $\bar{D}$ 1 (β†’ $\bar{D}$ Ο€ + Ο€ - ) $\ell$ + Ξ½ $\ell$ and measurement of the B β†’ $\bar{D}$ (*) Ο€$\ell$ + Ξ½ $\ell$ and B β†’ $\bar{D}$ (*) Ο€ + Ο€ - $\ell$+ Ξ½ $\ell$ branching fractions with hadronic tagging at Belle

We report measurements of the ratios of branching fractions for B β†’ $\bar{D}$(*) Ο€$\ell$+ v $\ell$ and B β†’ $\bar{D}$(*)Ο€ + Ο€ - $\ell$ + v $\ell$ relative to B β†’ $\bar{D}$*$\ell$ + v $\ell$ decays with $\ell$ = e, ΞΌ. These results are obtained from a data sample that contains 772 Γ— 10 6 $B\bar{B}$ pairs collected near the $\Upsilon$(4S) resonance with the Belle detector at the KEKB asymmetric energy e + e - collider.

79 ASTRONOMY AND ASTROPHYSICS↗