Showing papers by "B. G. Fulsom published in 2023"
TL;DR: In this article , a new structure is found in the MΣc(2455)0,++π± spectrum with a significance of 4.2σ including systematic uncertainty.
Abstract: We present the study of B¯0→Σc(2455)0,++π±p¯ decays based on 772×106 BB¯ events collected with the Belle detector at the KEKB asymmetric-energy e+e− collider. The Σc(2455)0,++ candidates are reconstructed via their decay to Λc+π∓ and Λc+ decays to pK−π+, pKS0, and Λπ+ final states. The corresponding branching fractions are measured to be B(B¯0→Σc(2455)0π+p¯)=(1.09±0.06±0.07)×10−4 and B(B¯0→Σc(2455)++π−p¯)=(1.84±0.11±0.12)×10−4, which are consistent with the world average values with improved precision. A new structure is found in the MΣc(2455)0,++π± spectrum with a significance of 4.2σ including systematic uncertainty. The structure is possibly an excited Λc+ and is tentatively named Λc(2910)+. Its mass and width are measured to be (2913.8±5.6±3.8) MeV/c2 and (51.8±20.0±18.8) MeV, respectively. The products of branching fractions for the Λc(2910)+ are measured to be B(B¯0→Λc(2910)+p¯)×B(Λc(2910)+→Σc(2455)0π+)=(9.5±3.6±1.6)×10−6 and B(B¯0→Λc(2910)+p¯)×B(Λc(2910)+→Σc(2455)++π−)=(1.24±0.35±0.10)×10−5. Here, the first and second uncertainties are statistical and systematic, respectively.Received 19 June 2022Revised 31 July 2022Accepted 23 August 2022DOI:https://doi.org/10.1103/PhysRevLett.130.031901Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBranching fractionParticle decaysPhysical SystemsCharmed baryonsParticles & Fields
2 citations
TL;DR: In this article , the authors measured the lifetime and frequency of the $B^0$ lifetime of the Belle II experiment in asymmetric-energy $e^+e^-$ collisions produced by the SuperKEKB collider operating at the Upsilon(4S) resonance.
Abstract: We measure the $B^0$ lifetime and flavor-oscillation frequency using $B^0\to D^{(*)-}\pi^+$ decays collected by the Belle II experiment in asymmetric-energy $e^+e^-$ collisions produced by the SuperKEKB collider operating at the $\Upsilon(4S)$ resonance. We fit the decay-time distribution of signal decays, where the initial flavor is determined by identifying the flavor of the other $B$ meson in the event. The results, based on $33000$ signal decays reconstructed in a data sample corresponding to ${190}\text{fb}^{-1}$, are $\tau_{B^0} = {1.499}\pm{0.013}\pm{0.008}\;\text{ps}$, $\Delta m_d = {0.516}\pm{0.008}\pm{0.005}\;\text{ps}^{-1}$, where the first uncertainties are statistical and the second are systematic. These results are consistent with the world-average values.
2 citations
TL;DR: In this article , the first measurement of the Michel parameter ξ (cid:48) in the τ − → µ − ¯ ν µ ν τ decay was reported.
Abstract: We report the first measurement of the Michel parameter ξ (cid:48) in the τ − → µ − ¯ ν µ ν τ decay. The measurement is based on the reconstruction of the τ − → µ − ¯ ν µ ν τ events with subsequent muon decay-in-flight in the Belle central drift chamber. The analyzed data sample of 988 fb − 1 collected by the Belle detector corresponds to approximately 912 × 10 6 τ + τ − pairs. We measure ξ (cid:48) = 0 . 22 ± 0 . 94(stat) ± 0 . 42(syst), which is in agreement with the Standard Model prediction of ξ (cid:48) = 1.
2 citations
2 citations
02 May 2023
TL;DR: In this article , a measurement of the branching fractions of four $B^{0,-}to D^{(*)+,0} K^- K_S^0_S$ decay modes is presented.
Abstract: We present a measurement of the branching fractions of four $B^{0,-}\to D^{(*)+,0} K^- K^{0}_S$ decay modes. The measurement is based on data from SuperKEKB electron-positron collisions at the $\Upsilon(4S)$ resonance collected with the Belle II detector and corresponding to an integrated luminosity of ${362~\text{fb}^{-1}}$. The event yields are extracted from fits to the distributions of the difference between expected and observed $B$ meson energy to separate signal and background, and are efficiency-corrected as a function of the invariant mass of the $K^-K_S^0$ system. We find the branching fractions to be: \[ \text{B}(B^-\to D^0K^-K_S^0)=(1.89\pm 0.16\pm 0.10)\times 10^{-4}, \] \[ \text{B}(\overline B{}^0\to D^+K^-K_S^0)=(0.85\pm 0.11\pm 0.05)\times 10^{-4},\] \[ \text{B}(B^-\to D^{*0}K^-K_S^0)=(1.57\pm 0.27\pm 0.12)\times 10^{-4}, \] \[ \text{B}(\overline B{}^0\to D^{*+}K^-K_S^0)=(0.96\pm 0.18\pm 0.06)\times 10^{-4},\] where the first uncertainty is statistical and the second systematic. These results include the first observation of $\overline B{}^0\to D^+K^-K_S^0$, $B^-\to D^{*0}K^-K_S^0$, and $\overline B{}^0\to D^{*+}K^-K_S^0$ decays and a significant improvement in the precision of $\text{B}(B^-\to D^0K^-K_S^0)$ compared to previous measurements.
1 citations
TL;DR: In this article , the authors measured the decay rate ratio of branching fractions for the 4S resonance with the Belle detector and found that the decay ratio was 1.065/pm 0.047, which is the most precise measurement.
Abstract: We measure the ratio of branching fractions for the $\Upsilon (4S)$ decays to $B^+B^-$ and $B^0\bar{B}{}^0$ using $B^+ \rightarrow J/\psi(\ell\ell) K^+$ and $B^0 \rightarrow J/\psi(\ell\ell) K^0$ samples, where $J/\psi(\ell\ell)$ stands for $J/\psi \to \ell^+\ell^-$ ($\ell = e$ or $\mu$), with $711$ fb$^{-1}$ of data collected at the $\Upsilon(4S)$ resonance with the Belle detector. We find the decay rate ratio of $\Upsilon(4S) \rightarrow B^+B^-$ over $\Upsilon(4S) \rightarrow B^0\bar{B}{}^0$ to be $1.065\pm0.012\pm 0.019 \pm 0.047$, which is the most precise measurement to date. The first and second uncertainties are statistical and systematic, respectively, and the third uncertainty is systematic due to the assumption of isospin symmetry in $B \to J/\psi(\ell\ell) K$.
1 citations
17 Jan 2023
TL;DR: In this article , the authors propose a solution to solve the problem of the problem: this article ] of "uniformity" and "uncertainty" of the solution.
Abstract: ,
1 citations
TL;DR: The first measurement of the Michel parameter in the τ − → µ − → e − ¯ ν µ ν τ decay with the full data sample of 988 fb − 1 collected by the Belle detector operating at the KEKB asymmetric energy e + e − collider was presented in this article .
Abstract: We present the first measurement of the Michel parameter ξ ′ in the τ − → µ − ¯ ν µ ν τ decay using the full data sample of 988 fb − 1 collected by the Belle detector operating at the KEKB asymmetric energy e + e − collider. The method is based on the reconstruction of the µ − → e − ¯ ν e ν µ decay-in-flight in the Belle central drift chamber and relies on the correlation between muon spin and its daughter electron momentum. We study the main sources of the background that can imitate the signal decay, such as kaon and pion decays-in-flight and charged particle scattering on the detector material. Highly efficient methods of their suppression are developed and applied to select 165 signal-candidate events. We obtain ξ ′ = 0 . 22 ± 0 . 94 ± 0 . 42 where the first uncertainty is statistical, and the second one is systematic. The result is in agreement with the Standard Model prediction of ξ ′ = 1.
1 citations
07 Feb 2023
TL;DR: In this article , the authors presented the first search for the weak radiative decays (Lambda_c^+ \to \Sigma+ \gamma) and the weak gamma decays with a data sample of 980~fb$^{-1}$ collected by the Belle detector operating at the KEKB asymmetric-energy $e^+e^-$ collider.
Abstract: We present the first search for the weak radiative decays $\Lambda_c^+ \to \Sigma^+ \gamma$ and $\Xi_c^0 \to \Xi^0 \gamma$ using a data sample of 980~fb$^{-1}$ collected by the Belle detector operating at the KEKB asymmetric-energy $e^+e^-$ collider. There are no evident $\Lambda_c^+ \to \Sigma^+ \gamma$ or $\Xi_c^0 \to \Xi^0 \gamma$ signals. Taking the decays $\Lambda_c^+ \to p K^- \pi^+$ and $\Xi_c^0 \to \Xi^- \pi^+$ as normalization channels, the upper limits at 90\% credibility level on the ratios of branching fractions ${\cal B}(\Lambda_c^+ \to \Sigma^+ \gamma)/{\cal B}(\Lambda_c^+ \to p K^{-} \pi^+) < 4.0 \times 10^{-3}$ and ${\cal B}(\Xi_c^0 \to \Xi^0 \gamma)/{\cal B}(\Xi_c^0 \to \Xi^- \pi^+) < 1.2 \times 10^{-2}$ are determined. We obtain the upper limits at 90\% credibility level on the absolute branching fractions ${\cal B}(\Lambda_c^+ \to \Sigma^+ \gamma) < 2.6 \times 10^{-4}$ and ${\cal B}(\Xi_c^0 \to \Xi^0 \gamma) < 1.8 \times 10^{-4}$.
1 citations
TL;DR: In this article , the authors used the Belle detector operating at the KEKB asymmetric-energy e + e − collider to investigate the π + and π − invariant mass distributions and found a significant signal in each mass distribution when interpreted as resonances.
Abstract: Using the data sample of 980 fb − 1 collected with the Belle detector operating at the KEKB asymmetric-energy e + e − collider, we present the results of an investigation of the Λ π + and Λ π − invariant mass distributions looking for substructure in the decay Λ + c → Λ π + π + π − . We find a significant signal in each mass distribution. When interpreted as resonances, we find for the Λ π + (Λ π − ) combination a mass of 1434 . 3 ± 0 . 6(stat . ) +0 . 9 − 0 . 0 (syst . ) MeV/ c 2 (1438 . 5 ± 0 . 9(stat . ) +0 . 2 − 2 . 5 (syst . ) MeV/ c 2 ), an intrinsic width of 11 . 5 ± 2 . 8(stat . ) +0 . 1 − 5 . 3 (syst . ) MeV/ c 2 (33 . 0 ± 7 . 5(stat . ) +0 . 1 − 23 . 6 (syst . ) MeV/ c 2 ) with a significance of 7.5 σ (6.2 σ ). As these two signals are very close to the ¯ KN threshold, we also investigate the possibility of a ¯ KN cusp, and find that we cannot discriminate between these two interpretations due to the limited size of the data sample.
15 Feb 2023
TL;DR: In this article , the heavy-flavor-conserving decay Ξc0→Λc+π− with Λc + reconstructed via its pK−π+ decay mode was studied.
Abstract: Based on a data sample of 983 fb−1 collected with the Belle detector at the KEKB asymmetric-energy e+e− collider, we present the study of the heavy-flavor-conserving decay Ξc0→Λc+π− with Λc+ reconstructed via its pK−π+ decay mode. The branching fraction ratio B(Ξc0→Λc+π−)/B(Ξc0→Ξ−π+) is measured to be 0.38±0.04±0.04. Combining with the world average value of B(Ξc0→Ξ−π+), the branching fraction B(Ξc0→Λc+π−) is deduced to be (0.54±0.05±0.05±0.12)%. Here, the uncertainties above are statistical, systematic, and from B(Ξc0→Ξ−π+), respectively.Received 17 June 2022Accepted 28 July 2022DOI:https://doi.org/10.1103/PhysRevD.107.032005Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Physical SystemsCharmed baryonsGeneral Physics
01 Jun 2023
TL;DR: In this paper , the authors measured the lifetime of the $D_s^+$ meson using a data sample of 207 fb$^{-1}$ collected by the Belle II experiment running at the SuperKEKB asymmetric-energy $e^+ e^-$ collider.
Abstract: We measure the lifetime of the $D_s^+$ meson using a data sample of 207 fb$^{-1}$ collected by the Belle II experiment running at the SuperKEKB asymmetric-energy $e^+ e^-$ collider. The lifetime is determined by fitting the decay-time distribution of a sample of $116\times 10^3$ $D_s^+\rightarrow\phi\pi^+$ decays. Our result is $\tau^{}_{D^+_s} = (498.7\pm 1.7\,^{+1.1}_{-0.8})$ fs, where the first uncertainty is statistical and the second is systematic. This result is significantly more precise than previous measurements.
TL;DR: In this article , the authors obtained exclusion limits at 90% Bayesian credibility in the range of 1.7×10−8−8-200× 10−8 on the effective coupling ϵ2×αD for the dark photon A′ and the dark Higgs boson h′ with an integrated luminosity of 8.34 fb−1.
Abstract: The dark photon A′ and the dark Higgs boson h′ are hypothetical particles predicted in many dark sector models. We search for the simultaneous production of A′ and h′ in the dark Higgsstrahlung process e+e−→A′h′ with A′→μ+μ− and h′ invisible in electron-positron collisions at a center-of-mass energy of 10.58 GeV in data collected by the Belle II experiment in 2019. With an integrated luminosity of 8.34 fb−1, we observe no evidence for signal. We obtain exclusion limits at 90% Bayesian credibility in the range of 1.7–5.0 fb on the cross section and in the range of 1.7×10−8–200×10−8 on the effective coupling ϵ2×αD for the A′ mass in the range of 4.0 GeV/c2
DOI•
19 Mar 2023
TL;DR: In this article , the first measurement of the Michel parameter was reported, which is based on the reconstruction of the $\tau-\to-mu-\bar{
u}_\mu
u_\tau$ decay with subsequent muon decay-in-flight in the Belle central drift chamber.
Abstract: We report the first measurement of the Michel parameter $\xi^\prime$ in the $\tau^-\to\mu^-\bar{
u}_\mu
u_\tau$ decay with a new method proposed just recently. The measurement is based on the reconstruction of the $\tau^-\to\mu^-\bar{
u}_\mu
u_\tau$ events with subsequent muon decay-in-flight in the Belle central drift chamber. The analyzed data sample of $988\,\text{fb}^{-1}$ collected by the Belle detector corresponds to approximately $912\times10^6$ $\tau^+ \tau^-$ pairs. We measure $\xi^\prime=0.22\pm0.94(\text{stat})\pm0.42(\text{syst})$, which is in agreement with the standard model prediction of $\xi^\prime=1$. Statistical uncertainty dominates in this study, being a limiting factor, while systematic uncertainty is well under control. Our analysis proved the practicability of this promising method and its prospects for further precise measurement in future experiments.
TL;DR: An absolute measurement of the Λc+ lifetime was reported in this paper , where the authors used the Belle II experiment at the SuperKEKB asymmetric-energy electron-positron collider.
Abstract: An absolute measurement of the Λc+ lifetime is reported using Λc+→pK−π+ decays in events reconstructed from data collected by the Belle II experiment at the SuperKEKB asymmetric-energy electron-positron collider. The total integrated luminosity of the data sample, which was collected at center-of-mass energies at or near the ϒ(4S) resonance, is 207.2 fb−1. The result, τ(Λc+)=203.20±0.89±0.77 fs, where the first uncertainty is statistical and the second systematic, is the most precise measurement to date and is consistent with previous determinations.Received 29 June 2022Accepted 25 July 2022DOI:https://doi.org/10.1103/PhysRevLett.130.071802Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasHadronic decaysLifetimes & widthsPhysical SystemsCharmed baryonsParticles & Fields
27 Feb 2023
TL;DR: In this article , a coherent sum model for the angular distribution of the S- and P-wave was constructed, and the ratio of their amplitudes, the relative phase and the forward-backward asymmetry was investigated.
Abstract: We study the decay B+→K+K−π+ and investigate the angular distribution of K+K− pairs with invariant mass below 1.1 GeV/c2. This region exhibits both a strong enhancement in signal and very large direct CP violation. We construct a coherent sum model for the angular distribution of the S- and P-wave, and report the ratio of their amplitudes, the relative phase and the forward-backward asymmetry. We also report absolute differential branching fractions and direct CP asymmetry for the decay in bins of MK+K− and the differential branching fractions in bins of MK+π−. The results are based on a data sample that contains 772×106 BB¯ pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. The result favors the presence of S- and D-waves in low MK+K− region to the detriment of a P-wave.1 MoreReceived 24 June 2022Accepted 3 February 2023DOI:https://doi.org/10.1103/PhysRevD.107.032013Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBranching fractionHadronic decaysParticle decaysRare decaysPhysical SystemsMesonsPropertiesCP violationParticles & Fields
TL;DR: In this paper , the authors used the Belle detector operating at the KEKB asymmetric-energy e^{+}e^{-} collider to investigate the Λπ+} and π+π+π- invariant mass distributions.
Abstract: Using the data sample of 980 fb^{-1} collected with the Belle detector operating at the KEKB asymmetric-energy e^{+}e^{-} collider, we present the results of an investigation of the Λπ^{+} and Λπ^{-} invariant mass distributions looking for substructure in the decay Λ_{c}^{+}→Λπ^{+}π^{+}π^{-}. We find a significant signal in each mass distribution. When interpreted as resonances, we find for the Λπ^{+} (Λπ^{-}) combination a mass of 1434.3±0.6(stat)±0.9(syst) MeV/c^{2} [1438.5±0.9(stat)±2.5(syst) MeV/c^{2}], an intrinsic width of 11.5±2.8(stat)±5.3(syst) MeV/c^{2} [33.0±7.5(stat)±23.6(syst) MeV/c^{2}] with a significance of 7.5σ (6.2σ). As these two signals are very close to the K[over ¯]N threshold, we also investigate the possibility of a K[over ¯]N cusp, and find that we cannot discriminate between these two interpretations due to the limited size of the data sample.
05 Jun 2023
TL;DR: In this paper , the authors search for long-lived spin-0 particles in the B$-meson decays mediated by a $b\to s$ quark transition in $e^+e^-$ collisions at the Belle II experiment.
Abstract: Additional spin-0 particles appear in many extensions of the standard model. We search for long-lived spin-0 particles $S$ in $B$-meson decays mediated by a $b\to s$ quark transition in $e^+e^-$ collisions at the $\Upsilon(4S)$ resonance at the Belle II experiment. Based on a sample corresponding to an integrated luminosity of $189 \mathrm{\,fb}^{-1}$, we observe no evidence for signal. We set model-independent upper limits on the product of branching fractions $\mathrm{Br}(B^0\to K^*(892)^0(\to K^+\pi^-)S)\times \mathrm{Br}(S\to x^+x^-)$ and $\mathrm{Br}(B^+\to K^+S)\times \mathrm{Br}(S\to x^+x^-)$, where $x^+x^-$ indicates $e^+e^-, \mu^+\mu^-, \pi^+\pi^-$, or $K^+K^-$, as functions of $S$ mass and lifetime at the level of $10^{-7}$.
DOI•
01 Feb 2023
TL;DR: In this paper , a new mechanism has been proposed to simultaneously explain the presence of dark matter and the matter-antimatter asymmetry in the universe, which predicts exotic $B$ meson decays into a baryon and a dark sector anti-baryon with branching fractions accessible at factories.
Abstract: A new mechanism has been proposed to simultaneously explain the presence of dark matter and the matter-antimatter asymmetry in the universe. This scenario predicts exotic $B$ meson decays into a baryon and a dark sector anti-baryon ($\psi_D$) with branching fractions accessible at $B$ factories. We present a search for $B \rightarrow \Lambda \psi_D$ decays using data collected by the $BABAR$ experiment at SLAC. This reaction is identified by fully reconstructing the accompanying $B$ meson and requiring the presence of a single $\Lambda$ baryon in the remaining particles. No significant signal is observed, and bounds on the $B \rightarrow \Lambda \psi_D$ branching fraction are derived in the range $0.13 - 5.2\times 10^{-5}$ for $1.0
05 Jun 2023
TL;DR: In this article , the authors measured the branching fraction ratio and the unitarity triangle angle in electron-positron collisions at the Upsilon(4S) resonance, and provided model-independent information on the triangle angle.
Abstract: We measure $C\!P$ asymmetries and branching-fraction ratios for $B^\pm \to DK^\pm$ and $D\pi^\pm$ decays with $D\to K^0_{\rm S} K^\pm\pi^\mp$, where $D$ is a superposition of $D^0$ and $\bar{D}^0$. We use the full data set of the Belle experiment, containing $772\times 10^6~B\bar{B}$ pairs, and data from the Belle~II experiment, containing $387\times 10^6~B\bar{B}$ pairs, both collected in electron-positron collisions at the $\Upsilon(4S)$ resonance. Our results provide model-independent information on the unitarity triangle angle $\phi_3$.
TL;DR: In this paper , the authors present a study of the X(3872) lineshape in the decay of B→X( 3872)K→D0D¯*0K using a data sample of 772×106 BB¯ pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider.
Abstract: We present a study of the X(3872) lineshape in the decay B→X(3872)K→D0D¯*0K using a data sample of 772×106 BB¯ pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. The peak near the threshold in the D0D¯*0 invariant mass spectrum is fitted using a relativistic Breit-Wigner lineshape. We determine the mass and width parameters to be mBW=3873.71−0.50+0.56(stat)±0.13(syst) MeV/c2 and ΓBW=5.2−1.5+2.2(stat)±0.4(syst) MeV, respectively. The branching fraction is found to be B(B+→X(3872)K+)×B(X(3872)→D0D¯*0)=(0.97−0.18+0.21(stat)±0.10(syst))×10−4. The signal from B0 decays is observed for the first time with 5.2σ significance, and the ratio of branching fractions between charged and neutral B decays is measured to be B(B0→X(3872)K0)/B(B+→X(3872)K+)=1.34−0.40+0.47(stat)−0.12+0.10(syst). The peak is also studied using a Flatté lineshape. We determine the lower limit on the DD¯* coupling constant g to be 0.075 at 95% credibility in the parameter region where the ratio of g to the mass difference from the D0D¯*0 threshold is equal to −15.11 GeV−1, as measured by LHCb.Received 3 February 2023Accepted 15 May 2023DOI:https://doi.org/10.1103/PhysRevD.107.112011Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Physical SystemsExotic mesonsParticles & Fields
16 Feb 2023
TL;DR: In this article , the authors present a study of rare decay modes B+→Ds+h0, B−→Ds*+h 0, D−→D−0, and D−h0 decay modes using a data sample of (772±10)×106 BB¯ events produced at the ϒ(4S) resonance.
Abstract: We present a study of rare decay modes B+→Ds+h0, B+→Ds*+h0, and B+→D+h0, where h0 denotes the neutral meson η or K0, using a data sample of (772±10)×106 BB¯ events produced at the ϒ(4S) resonance. The data were collected by the Belle detector operating at the asymmetric-energy KEKB collider. We find no evidence for these decays, so we set upper limits at the 90% confidence level on the branching fractions of B+→Ds+h0, Ds*+h0, and D+h0 decay modes. Along with these rare decay modes, we report improved measurements of the color-suppressed decay branching fractions B(B¯0→D0η)=(26.6±1.2±2.1)×10−5 and B(B¯0→D0K¯0)=(5.6±0.5±0.2)×10−5. The first and second quoted uncertainties are statistical and systematic, respectively.Received 1 September 2022Accepted 17 January 2023DOI:https://doi.org/10.1103/PhysRevD.107.L031101Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Particles & Fields
09 Mar 2023
TL;DR: In this paper , the authors presented a search for the decay X(3872)→π+π−π0 in the (772±11)×106 ϒ(4S)→BB¯ data sample collected at the Belle detector.
Abstract: We present a search for the decay X(3872)→π+π−π0 in the (772±11)×106 ϒ(4S)→BB¯ data sample collected at the Belle detector, where the X(3872) is produced in B±→K±X(3872) and B0→KS0X(3872) decays. We do not observe a signal, and set 90% credible upper limits for two different models of the decay processes: if the decay products are distributed uniformly in phase space, B(X(3872)→π+π−π0)<1.3%, and if M(π+π−) is concentrated near the mass of the D0D¯0 pair in the process X(3872)→D0D¯*0+c.c.→D0D¯0π0→π+π−π0, B(X(3872)→π+π−π0)<1.2×10−3.Received 17 June 2022Accepted 26 September 2022DOI:https://doi.org/10.1103/PhysRevD.107.052004Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBranching fractionHadronic decaysQuantum chromodynamicsQuark modelStrong interactionParticles & Fields
22 May 2023
TL;DR: In this article , the authors used the Belle detector at the KEKB energy-asymmetric $e^+e^-$ collider to search for $C\!P$ violation using $T$-odd correlations in five four body decays.
Abstract: We search for $C\!P$ violation using $T$-odd correlations in five $D_{(s)}^{+}$ and $D_{(s)}^{-}$ four-body decays. Our analysis is based on 980 $\rm fb^{-1}$ of data collected by the Belle detector at the KEKB energy-asymmetric $e^+e^-$ collider. Our results for the $T$-odd $C\!P$-violating parameter $a^{T\text{-odd}}_{C\!P}$ are: $a^{T\text{-odd}}_{C\!P}({D^{+}\to K^{-}K^{+}\pi^{+}\pi^{0}}) = (+2.6\pm 6.6\pm 1.3 )\times10^{-3}$, $a^{T\text{-odd}}_{C\!P}({D^{+}\to K^{+}\pi^{-}\pi^{+}\pi^{0}}) = (-1.3\pm 4.2\pm 0.1 )\times10^{-2}$, $a^{T\text{-odd}}_{C\!P}({D^{+}\to K^{-}\pi^{+}\pi^{+}\pi^{0}}) = (+0.2\pm 1.5\pm 0.8 )\times10^{-3}$, $a^{T\text{-odd}}_{C\!P}({D_s^{+}\to K^{+}\pi^{-}\pi^{+}\pi^{0}}) = (-1.1\pm 2.2\pm 0.1 )\times10^{-2}$, and $a^{T\text{-odd}}_{C\!P}({D_s^{+}\to K^{-}K^{+}\pi^{+}\pi^{0}}) = (+2.2\pm 3.3\pm 4.3 )\times10^{-3}$, where the uncertainties are statistical and systematic, respectively. These results are the first such measurements and are all consistent with zero. They include the first measurement for a $D^+_s$ singly Cabibbo-suppressed decay, and the first measurement for a $D$ meson doubly Cabibbo-suppressed decay. We also measure $a^{T\text{-odd}}_{C\!P}$ in different subregions of phase space, where the decays are dominated by different intermediate resonance states such as $D^+\to\phi\rho^+$, $\bar{K}^{*0}K^{*+}$, and $\bar{K}^{*0}\rho^+$; and $D_s^+\to K^{*+}\rho^{0}$, $K^{*0}\rho^{+}$, $\phi\rho^+$, and $\bar{K}^{*0}K^{*+}$. No evidence for $C\!P$ violation is found.
30 Mar 2023
TL;DR: The first simultaneous determination of the absolute value of the Cabibbo-Kobayashi-Maskawa matrix element using exclusive and exclusive decays is performed with the full Belle data set at the Upsilon(4S) resonance, corresponding to an integrated luminosity of 711 fb${}^{-1} as mentioned in this paper .
Abstract: 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 $\Upsilon(4S)$ 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 $b \to u \ell \bar
u_\ell$ decay. We separate exclusive $B \to \pi \, \ell\, \bar
u_{\ell}$ decays from other inclusive $B \to X_u \, \ell\, \bar
u_{\ell}$ 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 $X_u$ system. 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 $B \to \pi \, \ell\, \bar
u_{\ell}$ form factor, we determine $\left|V_{ub}^{\mathrm{excl.}} \right| = (3.78 \pm 0.23 \pm 0.16 \pm 0.14)\times 10^{-3}$ and $\left|V_{ub}^{\mathrm{incl.}} \right| = (3.90 \pm 0.20 \pm 0.32 \pm 0.09)\times 10^{-3}$, respectively, with the uncertainties being the statistical error, systematic errors, and theory errors. The ratio of $\left|V_{ub}^{\mathrm{excl.}} \right| / \left|V_{ub}^{\mathrm{incl.}} \right| = 0.97 \pm 0.12$ is compatible with unity.
TL;DR: In this article , a measurement of the differential shapes of exclusive B→D*ℓν¯℔ (B=B−,B¯0 and ℓ=e, μ) decays with hadronic tag-side reconstruction for the full 711 fb−1 Belle dataset is presented.
Abstract: We present a measurement of the differential shapes of exclusive B→D*ℓν¯ℓ (B=B−,B¯0 and ℓ=e, μ) 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 |Vcb|CLN=(40.2±0.9)×10−3 and |Vcb|BGL=(40.7±1.0)×10−3 with the zero-recoil lattice QCD point F(1)=0.906±0.013. We also perform a study of the impact of beyond zero-recoil lattice QCD calculations on the |Vcb| determinations. Additionally, we present the lepton-flavor universality ratio Reμ=B(B→D*eν¯e)/B(B→D*μν¯μ)=0.993±0.023±0.023, the electron and muon forward-backward asymmetry and their difference ΔAFB=0.028±0.028±0.008, and the electron and muon D* longitudinal polarization fraction and their difference ΔFLD*=0.030±0.025±0.007. The uncertainties quoted correspond to the statistical and systematic uncertainties, respectively.8 MoreReceived 23 January 2023Accepted 5 May 2023DOI:https://doi.org/10.1103/PhysRevD.108.012002Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasForm factorsLeptonic, semileptonic & radiative decaysParticles & Fields
08 Feb 2023
TL;DR: In this article , the authors measured the branching fractions for the singly Cabibbo-suppressed decays D+→K+K−π+π++π0 and Ds+→ K+π−π+)+π +π0, based on the Belle experiment at the KEKB e+e− collider.
Abstract: We present measurements of the branching fractions for the singly Cabibbo-suppressed decays D+→K+K−π+π0 and Ds+→K+π−π+π0, and the doubly Cabibbo-suppressed decay D+→K+π−π+π0, based on 980 fb−1 of data recorded by the Belle experiment at the KEKB e+e− collider. We measure these modes relative to the Cabibbo-favored modes D+→K−π+π+π0 and Ds+→K+K−π+π0. Our results for the ratios of branching fractions are B(D+→K+K−π+π0)/B(D+→K−π+π+π0)=(11.32±0.13±0.26)%, B(D+→K+π−π+π0)/B(D+→K−π+π+π0)=(1.68±0.11±0.03)%, and B(Ds+→K+π−π+π0)/B(Ds+→K+K−π+π0)=(17.13±0.62±0.51)%, where the uncertainties are statistical and systematic, respectively. The second value corresponds to (5.83±0.42)×tan4θC, where θC is the Cabibbo angle; this value is larger than other measured ratios of branching fractions for a doubly Cabibbo-suppressed charm decay to a Cabibbo-favored decay. Multiplying these results by world average values for B(D+→K−π+π+π0) and B(Ds+→K+K−π+π0) yields B(D+→K+K−π+π0)=(7.08±0.08±0.16±0.20)×10−3, B(D+→K+π−π+π0)=(1.05±0.07±0.02±0.03)×10−3, and B(Ds+→K+π−π+π0)=(9.44±0.34±0.28±0.32)×10−3, where the third uncertainty is due to the branching fraction of the normalization mode. The first two results are consistent with, but more precise than, the current world averages. The last result is the first measurement of this branching fraction.Received 3 May 2022Accepted 28 September 2022DOI:https://doi.org/10.1103/PhysRevD.107.033003Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasElectroweak interactionPhysical SystemsCharmed mesonsTechniquesParticle decaysParticles & Fields
TL;DR: In this article , the lepton flavor violating decays B+→K+τ±ℓ∓, with ℓ=(e,μ), using the full data sample of 772×106 BB¯ pairs recorded by the Belle detector at the KEKB asymmetric-energy e+e− collider.
Abstract: We present a search for the lepton flavor violating decays B+→K+τ±ℓ∓, with ℓ=(e,μ), using the full data sample of 772×106 BB¯ pairs recorded by the Belle detector at the KEKB asymmetric-energy e+e− collider. We use events in which one B meson is fully reconstructed in a hadronic decay mode. We find no evidence for B±→K±τℓ decays and set upper limits on their branching fractions at the 90% confidence level in the (1−3)×10−5 range. The obtained limits are the world’s best results.Received 13 December 2022Accepted 4 May 2023DOI:https://doi.org/10.1103/PhysRevLett.130.261802Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasElectroweak interactionFlavor changing neutral currentsLeptonic, semileptonic & radiative decaysParticle decaysPhysical SystemsBottom mesonsBottom quarkHypothetical gauge bosonsLeptoquarksTechniquesLepton collidersMonte Carlo methodsParticle data analysisParticle detectorsParticles & Fields
TL;DR: In this paper , the authors propose a solution to solve the problem of the problem: this paper ] of "uniformity" and "uncertainty" of the solution.
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