arXiv subjects

A. Baur

Publications and source records attributed to A. Baur.

At least 19 recordsLinked to original sources

arXiv2026

Search for the lepton-flavor-violating decay $ \tau^{\pm} \to \mu^{\pm} \gamma$ at Belle II

We present a search for the lepton-flavor-violating decay $\tau^{\pm}\to\mu^{\pm}\gamma$ using a data sample that corresponds to an integrated luminosity of 428 fb$^{-1}$ recorded by the Belle II experiment at the SuperKEKB asymmetric-energy $e^{+}e^{-}$ collider. We employ a multivariate classifier to suppress the backgrounds from the Standard Model processes, and the signal extraction is performed using an extended maximum-likelihood fit. Since no significant excess over the expected background is observed, we set an upper limit on the branching fraction $\mathcal{B}(\tau^{\pm}\to\mu^{\pm}\gamma) < 9.5$ $ (12.2)\times10^{-8}$ at the 90\% (95\%) confidence level, using the CL${_s}$ technique.

hep-ex↗

arXiv2026

Search for axion-like particles decaying to two photons at Belle II

Axion-like particles (ALPs) are predicted in many extensions of the Standard Model and provide a well-motivated portal between visible and hidden sectors through their coupling to photons. We search for ALPs produced in the process $e^{+}e^{-}\to\gamma a$, $a\to\gamma\gamma$, using a data sample corresponding to an integrated luminosity of $408~\mathrm{fb}^{-1}$ recorded by the Belle~II detector at the SuperKEKB $e^{+}e^{-}$ collider. Events containing three photons are used to reconstruct the ALP as a narrow peak in the di-photon invariant mass spectrum over the range $0.17 < m_{a} < 9.80~\mathrm{GeV}/c^{2}$. No significant excess above background is observed. We set 95\% confidence level upper limits on the production cross section and on the ALP-photon coupling $g_{a\gamma\gamma}$, reaching sensitivities at the level of $10^{-4}~\mathrm{GeV}^{-1}$. The limits are the most restrictive to date over nearly the entire mass range $0.17 < m_{a} < 5.00~\mathrm{GeV}/c^{2}$, and improve upon previous results by up to a factor 9.

hep-ex↗

arXiv2026

First measurement of the masses of the $\Upsilon_1(1D)$ and $\Upsilon_3(1D)$ states and the energy dependence of the cross sections for $e^+e^-\to\Upsilon_J(1D)\eta$ and $e^+e^-\to\Upsilon_J(1D)\pi^+\pi^-$

We study the processes $e^+e^-\to\Upsilon_J(1D)\eta$ and $e^+e^-\to\Upsilon_J(1D)\pi^+\pi^-$ at center-of-mass energies $\sqrt{s}$=(10.73 -- 11.02) GeV using a $142.5\,\mathrm{fb}^{-1}$ data sample, including 122~fb$^{-1}$ near the $\Upsilon$(10860) peak ($\sqrt{s}$ = 10.866 GeV), collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. From the peak sample, the products of Born cross section times branching fraction are obtained for $\sigma_{\rm Born}(e^+e^-\to\Upsilon_J(1D)\eta)$ or $\sigma_{\rm Born}(e^+e^-\to\Upsilon_J(1D)\pi^+\pi^-)$ and ${\cal B}(\Upsilon_J(1D)\to\chi_{b1}\gamma)$ or ${\cal B}(\Upsilon_J(1D)\to\chi_{b2}\gamma)$ for each $\Upsilon_J(1D)$ state. The corresponding branching fractions for $\Upsilon(10860)$ decays are also obtained. The significances of the $\Upsilon_1(1D)$, $\Upsilon_2(1D)$, and $\Upsilon_3(1D)$ signals are 4.8$\sigma$, ${>}10\sigma$, and 3.0$\sigma$, respectively, including systematic uncertainties. The mass for $\Upsilon_2(1D)$ is measured to be $(10167.0\pm 1.0\pm 0.2)$ MeV/$c^2$, where the first and second uncertainties are statistical and systematic. The mass splittings $\Delta m_{12}=m(\Upsilon_2(1D))-m(\Upsilon_1(1D))$ and $\Delta m_{23}=m(\Upsilon_3(1D))-m(\Upsilon_2(1D))$ are $(11.8\pm1.5\pm0.4)$ MeV/$c^2$ and $(7.6\pm2.4\pm0.6)$ MeV/$c^2$, respectively.~We determine the energy dependence of the cross sections for $e^+e^-\to\Upsilon_J(1D)\eta$ and $e^+e^-\to\Upsilon_J(1D)\pi^+\pi^-$ for the $\Upsilon_1(1D)$, $\Upsilon_2(1D)$, and $\Upsilon_3(1D)$ states, combined.

hep-ex↗

arXiv2026

Search for the decay $B^+ \rightarrow K^+\tau^+\tau^-$ using data from the Belle and Belle II experiments

We report a search for the rare decay $B^{+} \rightarrow K^{+} \tau^{+} \tau^{-}$ using $1.2 \times 10^9$ $\Upsilon(4S)$ mesons produced near threshold in electron-positron collisions and collected by the Belle and Belle~II experiments. We fully reconstruct the hadronic decay of one $B$ meson produced in the $\Upsilon(4S)\rightarrow B^{+} B^{-}$ decay, and search for $B^{\pm}\rightarrow K^{\pm} \tau^{+}\tau^{-}$ candidates among the remaining collision products, reconstructing a charged kaon and leptonic decays of the $\tau$ leptons. We optimize the selection for best sensitivity and look for an excess over background at low values of the residual energy detected in the calorimeter after full event reconstruction. We observe no significant excess and set the limit $\mathcal{B}(B^{+}\rightarrow K^{+}\tau^{+}\tau^{-})< 0.56\times 10^{-3}$ at the 90% confidence level, improving on the only previous result by a factor of four.

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arXiv2026

Searches for charged-lepton-flavor violation in $\chi_{bJ}(1P)$ decays

We report the first searches for charged-lepton-flavor violation in decays of $\chi_{bJ}(1P)$ ($J=0, 1,$ and $2$) to a pair of charged leptons using 158 million $\Upsilon(2S)$ decays collected with the Belle detector in $e^+e^-$ collisions at the KEKB collider. No significant signal is observed, and we set upper limits on the branching fractions for $\chi_{bJ}(1P)$ decays to $e^\pm\mu^\mp$ at the level of $10^{-6}$ and to $e^\pm\tau^\mp$ or $\mu^\pm\tau^\mp$ at the level of $10^{-5}$. Limits on $\chi_{b0}(1P)$ decays are translated into bounds on the corresponding Wilson coefficients of scalar operators that mediate charged-lepton-flavor violation.

hep-ex↗

arXiv2026

Study of $e^+e^- \to \pi^+\pi^-\Upsilon(1D)$ at Belle II

The bottomonium spectrum, consisting of bound states of a $b$ quark and an anti-$b$ quark, provides an excellent laboratory for probing quantum chromodynamics in the non-perturbative regime. While $S$ and $P$-wave bottomonium states are well studied experimentally, information on $D$-wave states remains scarce. We search for $D$-wave bottomonium state via the decay of a vector bottomonium-like state $\Upsilon(10753)$ in the reaction $e^+e^- \to \pi^+\pi^- \Upsilon(1D)$, using $19.6~\mathrm{fb}^{-1}$ of data collected with the Belle II detector at center-of-mass energies $\sqrt{s} = 10.653, 10.701, 10.745$, and $10.805$~GeV, in the vicinity of the $\Upsilon(10753)$ resonance. No significant signals are observed. Upper limits at the 90% credibility level are set on the products of the cross sections and branching fractions, $\sigma[e^+e^- \to \pi^+\pi^- \Upsilon_2(1D)] \times \mathcal{B}[\Upsilon_2(1D) \to \gamma \chi_{b1}]$ and $\sigma[e^+e^- \to \pi^+\pi^- \Upsilon_3(1D)] \times \mathcal{B}[\Upsilon_3(1D) \to \gamma \chi_{b2}]$, at each center-of-mass energy.

hep-ex↗

arXiv2026

Study of $e^{+}e^{-}\to h^{+}h^{-}J/\psi~(h=\pi,~K,~p)$ via initial-state radiation at Belle~II

Using a data sample of 427.9 fb$^{-1}$ collected by the Belle~II detector at or near the $\Upsilon(4S)$ and $\Upsilon(10753)$ resonances, the cross sections for $e^+e^-\to h^+h^-J/\psi$ $(h=\pi/K/p)$ at center-of-mass energies ranging from 3.8 GeV or the production threshold to 5.5/6.0/7.0 GeV have been measured via initial-state radiation. The cross sections for the processes $e^+e^-\to \pi^+\pi^-J/\psi$ and $e^+e^-\to K^+K^-J/\psi$ are consistent with previously published results. The cross sections for these channels obtained by combining with previous Belle results are also given. The process $e^+e^-\to p\bar p J/\psi$ is investigated for the first time. The yields are small and no significant structure is observed in the cross section versus energy. Searches for vector charmonium-like states in the $h^+h^-J/\psi$ systems, and for associated intermediate states in the $h^{\pm} J/\psi$ systems, are also presented.

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arXiv2025

First search for $B \rightarrow X_{s} \nu \bar{\nu}$ decays

We report the first search for the flavor-changing neutral-current decays $B \rightarrow X_{s} \nu \bar{\nu}$, where $X_{s}$ is a hadronic system with strangeness equal to 1, in data collected with the Belle~II detector at the SuperKEKB asymmetric-energy $e^+e^-$ collider. The data sample corresponds to an integrated luminosity of $365~\textrm{fb}^{-1}$ collected at the $\Upsilon(4S)$ resonance and $43~\textrm{fb}^{-1}$ collected at a center-of-mass energy $60~\textrm{MeV}$ below resonance for estimation of $e^+e^-\to q\bar{q}$ continuum background. One of the $B$ mesons from the $\Upsilon(4S) \to B\bar{B}$ decay is fully reconstructed in a hadronic decay mode. The $B \to X_s \nu \bar{\nu}$ decay is reconstructed with a sum-of-exclusives approach that uses 30 $X_s$ decay modes. This approach provides high sensitivity to the inclusive decay, despite the presence of two undetected neutrinos. The search is performed in three regions of the $X_{s}$ mass, chosen to separate contributions from prominent resonances. We do not observe a significant signal and set upper limits at 90\% confidence level on the partial branching fractions for the regions $0.0 < M_{X_{s}} < 0.6~\textrm{GeV}/c^{2}$, $0.6 < M_{X_{s}} < 1.0~\textrm{GeV}/c^{2}$, and $1.0~\textrm{GeV}/c^{2} < M_{X_{s}}$ of $2.2 \times 10^{-5}$, $9.3 \times 10^{-5}$, and $30.9 \times 10^{-5}$, respectively. Combining the three mass regions, we obtain the upper limit on the branching fraction, $B(B \to X_s \nu \bar{\nu}) < 3.3 \times 10^{-4}$.

hep-ex↗

arXiv2025

Improved measurement of Born cross sections for $\chi_{bJ}\,\omega$ and $\chi_{bJ}\,(\pi^+\pi^-\pi^0)_{\rm non-\omega}$ ($J$ = 0, 1, 2) at Belle and Belle II

We study the processes $\chi_{bJ}\,\omega$ and $\chi_{bJ}\,(\pi^+\pi^-\pi^0)_{\rm non-\omega}$ ($J$ = 0, 1, 2) at center-of-mass energies $\sqrt{s}$ from 10.73 to 11.02 GeV using a $142.5\,\mathrm{fb}^{-1}$ data sample collected with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider; and at $\sqrt{s}\sim10.75$ GeV using a $19.8\,\mathrm{fb}^{-1}$ sample collected with Belle II at SuperKEKB. We find that the $\Upsilon(10753)$ state decays into $\chi_{bJ}\,\omega$ but not into $\chi_{bJ}\,(\pi^+\pi^-\pi^0)_{\rm non-\omega}$, while the $\Upsilon(10860)$ state, in contrast, decays into $\chi_{bJ}\,(\pi^+\pi^-\pi^0)_{\rm non-\omega}$ but not into $\chi_{bJ}\,\omega$. The mass and width of the $\Upsilon(10753)$ state are measured to be $(10756.1\pm3.4({\rm stat.})\pm2.7({\rm syst.}))$ MeV/$c^2$ and $(32.2\pm11.3({\rm stat.})\pm14.9({\rm syst.}))$ MeV. The products of the partial width to $e^+e^-$ and branching fractions for $\Upsilon(10753)\to\chi_{b1}\,\omega$ and $\Upsilon(10753)\to\chi_{b2}\,\omega$ are ($1.57\pm0.27({\rm stat.})\pm 0.22({\rm syst.})$) eV and ($1.39\pm0.41({\rm stat.})\pm 0.33({\rm syst.})$) eV.

hep-ex↗

arXiv2025

Observation of $e^+e^-\to\eta\Upsilon(2S)$ and search for $e^+e^-\to\eta\Upsilon(1S),~\gamma X_b$ at $\sqrt{s}$ near 10.75 GeV

We present an analysis of the processes $e^{+}e^{-}\to\eta\Upsilon(1S)$, $\eta\Upsilon(2S)$, and $\gamma X_b$ with $X_b\to\pi^+\pi^-\chi_{bJ},~\chi_{bJ}\to\gamma\Upsilon(1S)$ $(J=1,~2)$ reconstructed from $\gamma\gamma\pi^+\pi^-\ell^+\ell^-~(\ell=e,~\mu)$ final states in $19.6\rm~\rm fb^{-1}$ of Belle II data collected at four energy points near the peak of the $\Upsilon(10753)$ resonance. Here, $X_b$ is a hypothetical bottomonium-sector partner of the $X(3872)$. In the process $e^{+}e^{-} \to \eta \Upsilon(2S)$, we observe a signal with a significance that exceeds $6.0\sigma$. Based on an analysis of the Born cross-section, the hypothesis that these events are associated solely with the production of the $\Upsilon(5S)$ or $\Upsilon(10753)$ resonances is rejected at the level of 3.6$\sigma$. This suggests that the observed events are more likely to arise from a new state near the $B^{*}\bar{B}^{*}$ threshold or from a substantial continuum production. No significant signal is observed for $e^{+}e^{-}\to\eta\Upsilon(1S)$ or $\gamma X_b$. Upper limits on the Born cross sections for the processes $e^{+}e^{-}\to\eta\Upsilon(1S)$ and $e^{+}e^{-}\to\gamma X_b$ with $X_b\to\pi^+\pi^-\chi_{bJ}$ are determined.

hep-ex↗

arXiv2025

Search for $e^+ e^- \to \gamma\chi_{bJ}$ ($J$ = 0, 1, 2) near $\sqrt{s} = 10.746$ GeV at Belle II

We search for the $e^+ e^- \to \gamma \chi_{bJ}$ ($J$ = 0, 1, 2) processes at center-of-mass energies $\sqrt{s}$ = 10.653, 10.701, 10.746, and 10.804 GeV. These data were collected with the Belle II detector at the SuperKEKB collider and correspond to 3.5, 1.6, 9.8, and 4.7 fb$^{-1}$ of integrated luminosity, respectively. We set upper limits at the 90\% confidence level on the Born cross sections for $e^+ e^- \to \gamma \chi_{bJ}$ at each center-of-mass energy $\sqrt{s}$ near 10.746 GeV. The upper limits at 90\% confidence level on the Born cross sections for $e^+ e^- \to \gamma \chi_{b1}$ are significantly smaller than the corresponding measured values for $e^+e^-\to\omega\chi_{b1}$ and $e^+e^-\to\pi^+\pi^-\Upsilon(2S)$ at $\sqrt{s}$ = 10.746 GeV.

hep-ex↗

arXiv2025

Search for the lepton-flavor-violating $\tau^{-} \rightarrow e^{\mp} \ell^{\pm} \ell^{\mp}$ decays at Belle II

We present the result of a search for the charged-lepton-flavor violating decays $\tau^- \rightarrow e^\mp \ell^\pm \ell^-$, where $\ell$ is a muon or an electron, using a data sample with an integrated luminosity of 428 fb$^{-1}$ recorded by the Belle II experiment at the SuperKEKB $e^+e^-$ collider. The selection of $e^+e^- \to\tau^+\tau^-$ events containing a signal candidate is based on an inclusive-tagging reconstruction and on a boosted decision tree to suppress background. Upper limits on the branching fractions between 1.3 and 2.5 $\times 10^{-8}$ are set at the 90% confidence level. These results are the most stringent bounds to date for four of the modes.

hep-ex↗

arXiv2025

Model-agnostic likelihood for the reinterpretation of the $B^+\to K^+\nu\bar{\nu}$ measurement at Belle II

We recently measured the branching fraction of the $B^{+}\rightarrow K^{+}\nu\bar{\nu}$ decay using 362fb$^{-1}$ of on-resonance $e^+e^-$ collision data under the assumption of Standard Model kinematics, providing the first evidence for this decay. To facilitate future reinterpretations and maximize the scientific impact of this measurement, we publicly release the full analysis likelihood along with all necessary material required for reinterpretation under arbitrary theoretical models sensitive to this measurement. In this work, we demonstrate how the measurement can be reinterpreted within the framework of the Weak Effective Theory. Using a kinematic reweighting technique in combination with the published likelihood, we derive marginal posterior distributions for the Wilson coefficients, construct credible intervals, and assess the goodness of fit to the Belle II data. For the Weak Effective Theory Wilson coefficients, the posterior mode of the magnitudes $|C_\mathrm{VL}+C_\mathrm{VR}|$, $|C_\mathrm{SL}+C_\mathrm{SR}|$, and $|C_\mathrm{TL}|$ corresponds to the point ${(11.3, 0.0, 8.2)}$. The respective 95\% credible intervals are $[1.9, 16.2]$, $[0.0, 15.4]$, and $[0.0, 11.2]$.

hep-ex↗

arXiv2025

NuAncestor: an artificial satellite-borne star for accurate frequency calibration of ground-based EPRV spectrographs

The accuracy of state-of-the-art Extreme Precision Radial Velocity (EPRV) spectrographs depends on the access to extremely precise and stable wavelength calibration sources. There are several available calibration sources (e.g., emission lamps, laser frequency combs, reference cavities) that can be used to calibrate an astronomical spectrograph. However, the calibration as it is currently performed is always 'local'. In the proposed talk we will present the NuAncestor concept that proposes an accurate (absolute) and common wavelength calibration for astronomical high-resolution, high-precision spectrographs by embarking an optical frequency comb on-board a satellite equipped with an actively pointing telescope and precision orbitography. This calibration satellite shall be available and serve EPRV spectrographs in all major observatories around the world.

astro-ph.IM↗

arXiv2025

Observation of the decays $B^{+} \to \Sigma_{c}(2455)^{++} \overline{\Xi}_{c}^{-}$ and $B^{0} \to \Sigma_{c}(2455)^{0} \overline{\Xi}_{c}^{0}$

We report the first observation of the two-body baryonic decays $B^{+} \to \Sigma_{c}(2455)^{++} \overline{\Xi}_{c}^{-}$ and $B^{0} \to \Sigma_{c}(2455)^{0} \overline{\Xi}_{c}^{0}$ with significances of $7.3\,\sigma$ and $6.2\,\sigma$, respectively, including statistical and systematic uncertainties. The branching fractions are measured to be $\mathcal{B}(B^{+} \to \Sigma_{c}(2455)^{++} \overline{\Xi}_{c}^{-}) = (5.74 \pm 1.11 \pm 0.42_{-1.53}^{+2.47}) \times 10^{-4}$ and $\mathcal{B}(B^{0} \to \Sigma_{c}(2455)^{0} \overline{\Xi}_{c}^{0}) = (4.83 \pm 1.12 \pm 0.37_{-0.60}^{+0.72}) \times 10^{-4}$. The first and second uncertainties are statistical and systematic, respectively, while the third ones arise from the absolute branching fractions of $\overline{\Xi}_{c}^{-}$ or $\overline{\Xi}_{c}^{0}$ decays. The data samples used for this analysis have integrated luminosities of 711~$\mathrm{fb}^{-1}$ and 365~$\mathrm{fb}^{-1}$, and were collected at the $\Upsilon(4S)$ resonance by the Belle and Belle~II detectors operating at the KEKB and SuperKEKB asymmetric-energy $e^{+}e^{-}$ colliders, respectively.

hep-ex↗

arXiv2025

Measurement of the $ D^{0}\rightarrow K^{-}\pi^{+}e^{+}e^{-} $ branching fraction and search for $ D^{0}\rightarrow \pi^{+}\pi^{-}e^{+}e^{-} $ and $D^{0}\rightarrow K^{+}K^{-}e^{+}e^{-} $ decays at Belle

We present a study of the rare charm meson decays $ D^{0}\rightarrow K^{+}K^{-}e^{+}e^{-} $, $ \pi^{+}\pi^{-}e^{+}e^{-} $, and $ K^{-}\pi^{+}e^{+}e^{-} $ using a 942 fb$^{-1}$ data set collected by the Belle detector at the KEKB asymmetric-energy $ e^{+}e^{-} $ collider. We use $ D^{0} $ candidates identified by the charge of the pion in $ D^{*} \rightarrow D^{0} \pi $ decays and normalize the branching fractions to $ D^{0} \rightarrow K^{-}\pi^{+}\pi^{-}\pi^{+} $ decays. The branching fraction for decay $ D^{0} \rightarrow K^{-}\pi^{+}e^{+}e^{-} $ is measured to be (39.6 $\pm$ 4.5 (stat) $\pm$ 2.9 (syst)) $\times$ $10^{-7}$, with the dielectron mass in the $ \rho/\omega $ mass region $ 675 < m_{ee} < 875 $ MeV$/c^{2}$. We also search for $ D^{0}\rightarrow h^{-} h^{(\prime)+}e^{+}e^{-} $ ($ h^{(\prime)}=K,\,\pi $) decays with the dielectron mass near the $\eta$ and $\phi$ resonances, and away from these resonances for the $ K^{+}K^{-}e^{+}e^{-} $ and $ \pi^{+}\pi^{-}e^{+}e^{-} $ modes. For these modes, we find no significant signals and set 90$\%$ confidence level upper limits on their branching fractions at the $\mathcal{O}$(10$^{-7}$) level.

hep-ex↗

arXiv2025

Search for an Axion-Like Particle in $B\rightarrow K^{(*)} a (\rightarrow\gamma\gamma)$ Decays at Belle

We report a search for an axion-like particle $a$ in $B\rightarrow K^{(*)} a (\rightarrow\gamma\gamma)$ decays using data collected with the Belle detector at the KEKB asymmetric energy electron-positron collider. The search is based on a $711 \mathrm{fb^{-1}}$ data sample collected at the $\Upsilon 4S$ resonance energy, corresponding to a sample of $772\times10^6$ $\Upsilon 4S$ events. In this study, we search for the decay of the axion-like particle into a pair of photons, $a \rightarrow \gamma\gamma$. We scan the two-photon invariant mass in the range $0.16\ \mathrm{GeV/}c^2-4.50\ \mathrm{GeV}/c^2$ for the $K$ modes and $0.16\ \mathrm{GeV/}c^2-4.20\ \mathrm{GeV}/c^2$ for the $K^{*}$ modes. No significant signal is observed in any of the modes, and 90\% confidence level upper limits are established on the coupling to the $W$ boson, $g_aW$, as a function of $a$ mass. The limits range from $3 \times 10^{-6} \mathrm{GeV}^{-1}$ to $3 \times 10^{-5} \mathrm{GeV}^{-1}$, improving the current constraints on $g_aW$ by a factor of two over the most stringent previous experimental results.

hep-ex↗

arXiv2025

Determination of $|V_{cb}|$ using $B\to D\ell\nu_\ell$ Decays at Belle II

We present a determination of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ from the decay $B\to D\ell\nu_\ell$ using a $365~\mathrm{fb}^{-1}$ $e^+e^-\to\Upsilon(4S)\to B\bar B$ data sample recorded by the Belle II experiment at the SuperKEKB collider. The semileptonic decay of one $B$ meson is reconstructed in the modes $B^0\to D^-(\to K^+\pi^-\pi^-)\ell^+\nu_\ell$ and $B^+\to \bar D^0(\to K^+\pi^-)\ell^+\nu_\ell$, where $\ell$ denotes either an electron or a muon. Charge conjugation is implied. The second $B$ meson in the $\Upsilon(4S)$ event is not reconstructed explicitly. Using an inclusive reconstruction of the unobserved neutrino momentum, we determine the recoil variable $w=v_B\cdot v_D$, where $v_B$ and $v_D$ are the 4-velocities of the $B$ and $D$ mesons. We measure the total decay branching fractions to be $\mathcal{B}(B^0\to D^-\ell^+\nu_\ell)=(2.06 \pm 0.05\,(\mathrm{stat.}) \pm 0.10\,(\mathrm{sys.}))\%$ and $\mathcal{B}(B^+\to\bar D^0\ell^+\nu_\ell)=(2.31 \pm 0.04\,(\mathrm{stat.}) \pm 0.09\,(\mathrm{sys.}))\%$. We probe lepton flavor universality by measuring $\mathcal{B}(B\to De\nu_e)/\mathcal{B}(B\to D\mu\nu_\mu)=1.020 \pm 0.020\,(\mathrm{stat.})\pm 0.022\,(\mathrm{sys.})$. Fitting the partial decay branching fraction as a function of $w$ and using the average of lattice QCD calculations of the $B\to D$ form factor, we obtain $ |V_{cb}|=(39.2\pm 0.4\,(\mathrm{stat.}) \pm 0.6\,(\mathrm{sys.}) \pm 0.5\,(\mathrm{th.})) \times 10^{-3}$.

hep-ex↗