6 pages, 3 figures, accepted to PoS Proceedings of the 40th International Conference on High Energy physics - ICHEP2020 July 28 - August 6, 2020 Prague, Czech Republic (virtual meeting)
We report on the first measurements of branching fractions, CP-violating charge asymmetries, and longitudinal polarization fractions in charmless $B$ decays at the Belle II experiment. We use a sample of electron-positron collisions collected in 2019 and 2020 at the $Υ(4S)$ resonance that corresponds to 34.6 fb$^{-1}$ of integrated luminosity. The results are compatible with the known values, which indicates a good understanding of detector performance.
We report on the first Belle II measurements of branching fractions and CP-violating charge asymmetries in charmless $B$ decays. We use 34.6 fb$^{-1}$ from electron-positron collisions collected in 2019 and 2020 at the $Υ(4S)$ resonance. The results are compatible with known values and show performance already comparable with Belle.
Charmless hadronic $B$ decays are a good testing ground for the Standard Model (SM) of Particle Physics. The dominant amplitudes are CKM suppressed tree diagrams and/or $ b\to s$ or $b\to d$ loop ("penguin") diagrams. Non-SM particle could appear in the loop, and hence these decays are sensitive to search for New Physics (NP). Some of the recent measurements of two-body charmless hadronic $B$ decays from Belle and their prospects at Belle II are discussed.
Two-body charmless hadronic decays of $B$ mesons are important for determining Standard Model parameters and for detecting the presence of new physics. We present recent results from the Belle experiment on the charmless hadronic decays $B\rightarrow ηπ^0$ and $B\rightarrow π^0 π^0$.
The results on charmless B meson decays to three-body Khh final states, where h stands for the charged or neutral pion or kaon are presented. The data sample used in this analysis consists of 43 1/fb on-resonance data collected with the Belle detector operating at the KEKB collider.
We report on preliminary measurements of branching fractions, charge-parity-violating asymmetries, and longitudinal polarization fractions in charmless bottom-meson decays from the Belle~II experiment. We use samples of electron-positron collisions collected in 2019 and 2020 at the $Υ(4S)$ resonance, corresponding to integrated luminosities of up to 62.8 ${\rm fb^{-1}}$. The results are compatible with known values, indicating good understanding of early detector performance.
We report on recent results on charmless hadronic and radiative rare $B_s^0$ decays, based on the data collected by the Belle experiment at the KEKB $e^+e^-$ collider. These include the studies of $B_s^0\rightarrow K^0\bar{K^0}$, $B_s^0\rightarrowϕγ$ and $B_s^0\rightarrowγγ$.
We present measurements of time-dependent CP violation parameters in B0 --> K0 PI0, B0 --> Ks Pi+ Pi- and B0 --> Ks K+ K- decays. The latter two are extracted using time-dependent Dalitz plot analyses. These results are obtained from a large data sample that contains 657 x 10^6 BBbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider.
Using the data sample of 10.5 fb-1 collected by the Belle detector, we searched for two-body charmless decays involving vector mesons. The clear signal signature of B+ -> phi K+ is seen and its branching fraction is measured to be (1.39+.32-.30 +- 0.2) X 10-5. The evidence for B+ -> rho pi+, B0 -> rho- pi+ and B+ -> phi K*+ is reported and their branching fractions are determined. No significant signals are observed for B0 -> phi K0S, -> phi K*0, -> rho- K+, B+ -> rho K+, -> omega pi+ and -> omega K+ only the 90% C.L. upper limits are given.
Using a data sample of 21.3 fb$^{-1}$ collected by the Belle detector, three body charmless decays $B^+\to K^+ h^+ h^-$ have been studied. With no assumptions on the intermediate mechanisms, the following branching fractions have been measured for the first time $ {\cal{B}}(B^+\to K^+ π^- π^+) = (58.5\pm 7.1\pm 8.8)\times 10^{-6}$ and $ {\cal{B}}(B^+\to K^+ K^- K^+) = (37.0\pm 3.9\pm 4.4)\times 10^{-6}$. We also present the first observations of the decay mode $B^+\to K^{*0}(892)π^+$ with a branching fraction of ${\cal{B}}(B^+\to K^{*0}(892) π^+) = (16.7^{+3.7+2.1+3.0}_{-3.4-2.1-5.9})\times 10…
We report recent observations of baryonic B decays with charmless and charmed baryons in the final state. We show the angular distributions of the di-baryon low-mass enhancements in the charmless three-body baryonic B decays andthe branching fractions of B decays with two charmed baryons or charmonium in the final states. We also report the observation of the decay $η_c \to Λ\barΛ$ at Belle.
Hadronic $B$ decays without a charm quark constitute a powerful probe to search for physics beyond the standard model as well as to provide constraints on $CP$ violation parameters. We report final measurements from Belle of the branching fractions and $CP$ asymmetries for the decays $B^{0} \rightarrow π^{0} π^{0}$ and $B^{\pm} \rightarrow K^{+} K^{-} π^{\pm}$. The $B^{0} \rightarrow π^{0} π^{0}$ measurements enable us to improve constraints on the angle $ϕ_{2}$ of the CKM unitarity triangle. For $B^{\pm} \rightarrow K^{+} K^{-} π^{\pm}$ we measure $CP$ asymmetry as a function of the invariant…
We report the updated results of direct CP violation measurements from Belle and BaBar for the following modes: B -> h+h-/h+-pi^0, B -> eta(') h+- and B -> K+-pi+-pi-+, where h stands for a charged kaon or pion. The data used in these studies are up to 386 million BBbar pairs for Belle and 232 million BBbar pairs for BaBar. The current significant measurements include: Acp(B -> K+ pi-)=-0.108+/-0.016, Acp(B -> rho0(770) K+)=0.31+0.11-0.10, and Acp(B -> eta K+)=-0.33+/-0.12.
We report several new and updated results from Belle and BABAR for rare hadronic B decays. These include many new results for B decays to eta'X and omegaX and new measurements of the longitudinal polarisation in the decays B -> rho K*.
We report preliminary results of a Dalitz plot analysis of three-body charmless B0=>Kspi+pi- decays. The analysis is performed with a data sample that contains 386 million $B\bar{B}$ pairs collected near the Y(4S) resonance with the Belle detector at the KEKB asymmetric energy e+e- collider. Measurements of branching fractions for quasi-two-body decays B0=>rho(770)0K0, B0=>f0(980)K0, B0=>K*(892)+pi-, B0=>K*(1430)+pi-, and upper limits on several other quasi-two-body decay modes are reported.
We report on a study of charmless B meson decays to three-kaon final states. The results are obtained with a 78.7 1/fb data sample collected on the Y(4S) resonance by the Belle detector operating at the KEKB asymmetric energy $e^+e^-$ collider. The branching fractions for B decays to three-body K+K+K-, K0K+K-, KsKsK+, and KsKsKs final states are presented. We also make a first attempt to perform an isospin analysis of the three-kaon final states.
We report results on studies of CP violation in the three-body charmless decay B+- => K+-pi+-pi-+. Evidence at the 3.9sigma level for large direct CP violation in B+- => rho(770)0K+-$ is found. This is the first evidence for CP violation in a charged meson decay. The analysis is performed using Dalitz analysis technique with a data sample that contains 386 million BBbar pairs collected near the Y(4S) resonance, with the Belle detector operating at the KEKB asymmetric energy e+ e- collider.
The latest experimental results in charmless B decays are presented with a focus on CP violation measurements. These include the first observation of CP violation in B_s decays, evidence for CP violation in charmless three-body B+ decays, branching fraction measurements of B+ --> ppK+ decays and the first observation of the decay B_s --> phi K*0 from LHCb, a comparison of B+ --> K+K-K+ CP violation measurements between LHCb and BaBar, and the first evidence for the decay B0 --> K+K-pi0 obtained by Belle.
Using a data sample of 10.5 1/fb collected by the Belle detector, three-body charmless decays B+ --> K+h+h- have been studied. The following branching fractions have been obtained: Br(B+ --> K+pi-pi+) = (64.8+-10.0+-7.0) x 10**-6 and Br(B+ --> K+K-K+) = (36.5+-6.1+-5.5) x 10**-6. The upper limits for other combinations of charged kaons and pions have been placed. Analysis of the intermediate two-body states gives evidence for production of scalar resonances in charmless B decays.
We report results of a Dalitz plot analysis of the three-body charmless B0=>K0pi+pi- decay. The analysis is performed with a data sample that contains 388 million BBbar pairs collected near the Y(4S) resonance with the Belle detector at the KEKB asymmetric energy e+e- collider. Measurements of branching fractions for the quasi-two-body decays B0=>rho(770)0K0, B0=>f0(980)K0, B0=>K*(892)+pi-, B0=>K*(1430)+pi-, and upper limits on several other quasi-two-body decay modes are reported.
The Belle experiment has measured branching fractions and CP asymmetries for the charmless decays B0->pi+pi- and B0->rho+-pi-+. From these measurements, constraints upon the CKM angle phi_2 can be obtained. These constraints indicate that phi_2 is around 100 degrees.
We report on the measurement of inclusive charmless semileptonic B decays $B \to X_{u} \ell ν$. The analysis makes use of hadronic tagging and is performed on the full data set of the Belle experiment comprising 772 million $B\bar{B}$ pairs. In the proceedings, the preliminary results of measurements of partial branching fractions and the CKM matrix element $|V_{ub}|$ are presented.
A study of the charmless semileptonic decay B0 to pi- l+ nu using a large sample of untagged Upsilon(4S) to B Bbar events collected with the Belle detector at the KEKB asymmetric e+ e- collider is presented. The branching fraction of the decay is obtained and from this the Cabibbo-Kobayashi-Maskawa matrix element |Vub| is determined using two different approaches.
We report on recent measurements, from the BaBar and Belle experiments, of B-meson decays to purely hadronic final states that do not contain charm. The studies are based on large samples of BBbar pairs collected at the Upsilon(4S) or B_s(*)B_s(*) pairs collected at the Upsilon(5S) by the BaBar and Belle detectors at the asymmetric energy e+e- colliders at SLAC and KEK-B, respectively. This paper includes the following results: measurements of branching fractions and charge asymmetries of B meson decays to eta' rho, eta' f0, and eta' K*, where the K* stands for a vector, tensor, or scalar stra…
We report a preliminary study of the branching fractions and $q^2$ distributions of exclusive charmless semileptonic B decays, using events tagged by fully reconstructing one of the $B$ mesons in a hadronic decay mode. These results are obtained from a data sample that contains 535 $\times 10^6\ B\bar{B}$ pairs, collected near the $Υ(4S)$ resonance with the Belle detector at the KEKB asymmetric energy $e^+ e^-$ collider.
Recently Belle collaboration reported new measurements for the branching fractions with the first observing two processes of $\mathcal{B}(Ξ_c^0\toΛK^0_S)$, $\mathcal{B}(Ξ_c^0\toΣ^0 K^0_S)$ and updating data for $\mathcal{B}(Ξ_c^0\toΣ^+ K^-)$. Combined with other known data on charmless two body decays of anti-triplet charmed baryons, a lot of information can be derived with the assistance of $SU(3)$ flavour symmetry. Using $SU(3)$ relations between different decay modes, we can give some predictions based on the new measurements which can be tested with the high luminosity experiments in the f…
The Belle and BaBar experiments have measured branching fractions and CP asymmetries in the charmless decay modes B0->pi+pi-, B0->rho+pi-/rho-pi+, and B0->rho+rho-. From these measurements, constraints upon the CKM angle phi_2 can be obtained. These constraints consistently indicate that phi_2 is around 100 degrees.
We review recent experimental results on Bd and Bs mesons decays by the BaBar and Belle experiments. These include measurements of the color-suppressed decays B0bar to D(*)0h0, h0=pi0, eta, etaprime, omega, observation of the baryonic decay B0bar to Lambdac+ Lambdabar K-, measurements of the charmless decays B to eta h, h=K, pi, B to Kpi and observation of CP eigenstates in the Bs decays: B0s to J/psi f0(980), B0s to J/psi f0(1370) and B0s to J/psi eta. The theoretical implications of these results will be considered.
We report the results of a study of two-body B meson decays to the complete set of K pi, pi pi, and K K final states. The study is performed on a data sample of 31.7 +/- 0.3 million B B-bar events recorded on the Upsilon(4S) resonance by the Belle experiment at KEKB. We observe significant signals in all K pi final states and in the pi+ pi- and pi+ pi0 final states. We set limits on the pi0 pi0 and K K final states. A search is performed for partial-rate asymmetries between conjugate states for flavor-specific final states.
We present the partial branching fraction for inclusive charmless semileptonic B decays and the corresponding value of the CKM matrix element |Vub|, using a multivariate analysis method to access ~90% of the B -> Xu l nu phase space. This approach dramatically reduces the theoretical uncertainties from the b-quark mass and non-perturbative QCD compared to all previous inclusive measurements. The results are based on a sample of 657 million B -Bbar pairs collected with the Belle detector. We find that Delta BR(B -> Xu l nu; p^*B_l>1.0 GeV/c=1.963 x (1 +/- 0.088(stat.) +/- 0.081(sys.)) x 10^-3. …
We report results on a Dalitz analysis of three-body charmless B+-=>K+-pi+-pi-+ decay including searches for direct CP violation. We report the first observation of the decay B+=>f_2(1270)K+ with a statistical significance above 6sigma. We also observe 3.9sigma evidence for large direct CP violation in the B+-=>rho(770)0K+- channel. This is the first evidence for CP violation in a charged meson decay. The results are obtained with a data sample that contains 386 million BBbar pairs collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider.
We report branching fractions and CP asymmetries for $B \to ηK^*$ and $B \to ηρ$ decays. These results are obtained from a $414 {\rm fb}^{-1}$ data sample collected at the $Υ(4S)$ resonance, with the Belle detector at the KEKB asymmetric energy $e^+ e^-$ collider. The branching fractions, in parts per million, of $ηK^{*0}$, $ηK^{*+}$, $ηρ^0$, and $ηρ^+$ are $15.9\pm 1.2 \pm 0.9$, $19.7^{+2.0}_{-1.9} \pm 1.4$, $0.84^{+0.56}_{-0.51} \pm 0.18$, and $4.1^{+1.4}_{-1.3} \pm 0.34$, respectively. We find no evidence for CP asymmetries in these modes.
We report results on the Dalitz analysis of three-body charmless B+=>K+Pi+Pi- and B+=>K+K+K- decays based on a 140 fb$^{-1}$ data sample collected with the Belle detector. Measurements of branching fractions for quasi-two-body decays to scalar-pseudoscalar states: B+ => f0(980)K+, B+ => K*_0(1430)^0 Pi+, and to vector-pseudoscalar states: B+ => K*(892)^0 Pi+, B+ => rho(770)K+, B+ => phi(1020)K+ are presented. Upper limits on decays to some pseudoscalar-tensor final states are reported. We also report the measurement of the B+ => chi_c0 K+ branching fraction in two chi_c0 decays channels: chi_c…
We report on a search for the exclusive two-body charmless hadronic B meson decays B-> eta' rho, B-> eta' K*, B-> eta' phi, B-> eta' omega and B->eta' eta('). The results are obtained from a data sample containing 535 x 10^6 BBbar pairs that were collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ e- collider. We find no significant signals and report upper limits in the range 0.5-6.5 x 10^{-6} for all of the above decays.
In this paper, we focused on the recent progress of $γ/ϕ_{3}$ from $B\rightarrow DK$, DCPV effects in charmless hadronic $B_{(S)}$ decays and the prospects of SuperB and BelleII experiments.
We report the results of a search for the rare baryonic decays $B^0 \to p\bar{p}$, $Λ\barΛ$, and $B^+ \to p\barΛ$. The analysis is based on a data set of $31.7\times 10^6 B\bar{B}$ events collected by the Belle detector at the KEKB $e^+e^-$ collider. No statistically significant signals are found, and we set branching fraction upper limits ${\mathcal B}(B^0 \to p\bar{p}) < 1.2 \times 10^{-6}$, ${\mathcal B}(B^0 \to Λ\barΛ) < 1.0 \times 10^{-6}$, and ${\mathcal B}(B^+ \to p\barΛ) < 2.2 \times 10^{-6}$ at the 90% confidence level.
We report results of a study of charmless B meson decays to three-body KPiPi, KKPi and KKK final states. Measurements of branching fractions for B decays to K+0Pi+Pi-, K+K+K-, K0K+K-, KsKsK+ and KsKsKs final states are presented. The decays B0=>K0K+K-, B+=>KsKsK+ and B0=>KsKsKs are observed for the first time. We also report evidence for B+=>K+K-Pi+ decay. For the three-body final states K0K+K-, KsKsPi+, K+K+Pi- and K-Pi+Pi+ 90% confidence level upper limits are reported. Finally, we discuss the possibility of using the three-body B0=>KsK+K- decay for CP violation studies. The results are obta…
We report results of a search for the charmless two-body baryonic decays B^0 \to p \bar{p}, B^0 \to Λ\barΛ, and B^+\to p \barΛ based on the analysis of a 140 fb^{-1} data sample. We set 90% confidence level upper limits on their branching fractions: B(B^0 \to p \bar{p}) < 4.1 x 10^{-7}, B(B^0 \to Λ\barΛ) < 6.9 x 10^{-7}$, and B(B^+ \to p \barΛ) < 4.9 x 10^{-7}.
The large data sample being recorded with the Belle detector at the Y(5S) energy provides a unique opportunity to study the poorly-known Bs0 meson. Three analyses, using a sample of 23.6 /fb, are presented. We report the first observation of the three dominant exclusive Bs0 decays, Bs0 -> Ds*- pi+, Bs0 -> Ds- rho+ and Bs0 -> Ds*- rho+, the first observation of the CP-eigenstate decay Bs0 -> J/psi eta, and the results from a study of the charmless Bs0 -> K+K-, Bs0 -> K+pi-, Bs0 -> pi+pi- and Bs0 -> K0 K0bar decays.
We report results on the Dalitz analysis of three-body charmless B+=>K+pi+pi-, B0=>K0pi+pi- and B+=>K+K+K- decays including searches for direct CP violation in the B+=>K+pi+pi- mode. Branching fractions for a number of quasi-two-body intermediate states are reported. We also observe evidence with 3.9 sigma significance for a large direct CP violation in B+-=>rho(770)0K+- channel. This is the first evidence for CP violation in a charged meson decay. The results are obtained using a Dalitz analysis technique with a large data sample of BBbar pairs collected with the Belle detector operating at t…
We report the recent measurements of $B^0\to J/ψπ^0$ and other CP violation modes based on the data collected by the Belle experiment at the KEKB collider. The CP asymmetry parameters for the decay $B^0\to J/ψπ^0$ have previously been measured by BaBar and Belle experiments, but the results of mixing induced CP asymmetry $[S=-η_f\sin(2ϕ_1)]$ were not in good agreement with each other. Furthermore, the BaBar result lies outside the physically allowed region. Previous Belle measurements were based on $535\times10^6$ $B\bar{B}$ pairs. We updated the measurements using the final Belle data set of …
We report on a study of three-body charmless decays B+ => K+h+h-$ based on a 29.1 fb^{-1} data sample collected with the Belle detector. With no assumptions on the intermediate mechanisms, the following three-body branching fractions have been measured for the first time: Br(B+ => K+pi-pi+) = (55.6\pm5.8\pm7.7)x10^{-6} and Br(B+ => K+K-K+) = (35.3\pm3.7\pm4.5)x10^{-6}. We present the first observation of the decay B+ => f_0(980)K+ with a branching fraction product of Br(B+ => f_0(980)K+)xBr(f_0(980) => π+π-)= (9.6^{+2.5+1.5+3.4}_{-2.3-1.5-0.8})x10^{-6}. This is the first reported example of a …
We report measurements of charmless hadronic B^0 decays into the pi+pi-K+pi+ final state. The analysis uses a sample of 657x10^6 BBbar pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider at the Y(4S) resonance. The decay B^0 -> rho0 Kpi is observed for the first time; the significance is 5.0sigma and the corresponding partial branching fraction for M_Kpi in (0.75,1.20) GeV/c^2 is [2.8 +- 0.5(stat) +-0.5(syst)] x 10^{-6}. We also obtain the first evidence for B^0 -> f0Kpi with 3.5sigma significance and for B^0 -> pi+pi-K*0 with 4.5sigma significance. For the two-…
We give an overview of the experimental measurements and the theoretical understanding of the branching fractions and CP-violating asymmetries of charmless B-meson decays. Most experimetal results are from the BABAR and Belle experiments during the past decade. The global features of these experimental results are typically well described by the QCD-motivated theories such as QCD factorization, pQCD and soft-collinear effective theory. The agreement between theory and experiment is generally satisfactory, though there remain some unsolved puzzles that pose a great challenge to both theorists a…
We report a study of the charmless hadronic decay of the charged $B$ meson to the three-body final state $K^+ K^- π^+$. The results are based on a data sample that contains $772\times10^6$ $B \bar{B}$ pairs collected at the $Υ(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. The measured inclusive branching fraction and the direct $CP$ asymmetry are $(5.38\pm0.40\pm0.35)\times 10^{-6}$ and $-0.170\pm0.073\pm0.017$, respectively, where the first uncertainties are statistical and the second are systematic. The $K^{+}K^{-}$ invariant mass distribution of th…
We report the measurement of an inclusive partial branching fraction for charmless semileptonic B decay and the extraction of |V_{ub}|. Candidates for B-> X_u l nu are identified using a novel X_u-reconstruction method with simultaneous requirements on the hadronic recoil mass (M_X) and the invariant mass squared of lepton-neutrino system (q^2). Based on 86.9 fb^{-1} of data taken with the Belle detector, we obtain Delta{B}(B->X_u l nu ; M_X<1.7GeV, q^2>8.0GeV^2) = (7.37 +- 0.89(stat.) +- 1.12(syst.) +- 0.55(b ->c) +- 0.24(b->u)) x 10^{-4} and determine |V_{ub}| = (4.66 +- 0.28(stat.) +- 0.35(…
We present three analyses based on data samples collected by the Belle detector at the KEKB e+e- asymmetric energy collider. The first one contains the measurement of the branching fractions and q^2 distributions of exclusive charmless semileptonic B decays, which are used to extract the Cabibbo-Kobayashi-Maskawa matrix element |V_{ub}|. The sample of events is obtained by fully reconstructing one of the B mesons in selected hadronic modes. The second analysis determines the branching fraction and the form factors rho^2, R_1 and R_2 for the exclusive decay B^0 -> D^{*-} \ell^+ ν. These measure…
We study charmless $B^+$ meson decays to the $p \barΛ π^+ π^-$ final state using a $605 {\rm fb}^{-1}$ data sample collected at the $Υ(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. There are significant signals found with the $p\barΛ$ mass peaking near threshold. The observed branching fraction for non-resonant $ B^+ \to p \barΛ} π^+ π^-$ is $(5.92^{+0.88}_{-0.84} (stat.) \pm 0.69 (syst.)) \times 10^{-6}$ with a significance of 9.1 standard deviations. We also observe the intermediate three-body decay $B^+ \to p \barΛ ρ^0$ with a branching fraction of…
The experimental status of the polarization measurements in B to charmless vector-vector decays by both the Belle and Babar experiments is reviewed. The results obtained in related vector-tensor, axial vector-vector, and axial vector-axial vector modes are also given.
This proceeding reports a selection of recent experimental results concerning $C\!P$ violation in the sectors of $B^0$ and $B^\pm$ mesons. They were published within the last two years by the Belle, Belle II and LHCb collaborations. The first set of measurements is related to the determination of the angles of the Unitarity Triangle. The second is connected to another crucial test of the SM: the isospin sum rule of $B \to Kπ$ decays. Thirdly, studies of $C\!P$ violation in the decays charged $B$ mesons to charmless three-body final states are presented. Finally, prospects for the future experi…
I present the results of searches for B meson decays into two charmless mesons. I take into account final states made up of two pseudo-scalar (PP) or one pseudo-scalar and one vector (PV). The measurements use the data samples collected and analysed by the B-factory experiments at the $Υ(4S)$ resonance energy: BABAR, Belle and CLEO.
LHCb has a rich programme studying hadronic B-decays and is already showing that with early data it can produce precision measurements which improve on current world averages. The preliminary results presented include the new world's best measurements of the Acp(Bd -> K+ pi-) = -0.088 +/- 0.011 (stat) +/- 0.008 (syst) and tau(Bs -> K+ K-) = 1.440 +/- 0.096 (stat) +/- 0.010 (syst) ps. These were obtained using the full 2010 data sample containing 37 pb-1 and also 320 pb-1 of the 2011 data. The first observation of CP violation in Bs -> pi+ K- is also presented.
Belle II is an experiment designed to study billions of $τ$-lepton, $b$- and $c$-quark decays observed with low background in asymmetric-energy electron-positron collisions at the SuperKEKB $B$-factory. In March 2019, the newly completed Belle II started operating and collected its first physics data reaching 10 fb$^{-1}$ to date. We report the reconstruction of prominent signals from various hadronic $B$ decays including $B^{-}\to D^{(*)0}π^{-}$, $B^{0}\to D^{-}K^{+}$, and $B^{0}\to K^{+}π^{-}$ in the first data set corresponding to 5.15 fb$^{-1}$. These results show a remarkable level of ear…
We present a preliminary measurement of the inclusive charmless semileptonic branching fraction of the B meson, based on $140 fb^{-1}$ of data collected by the Belle detector at the KEKB $e^+e^-$ asymmetric collider. Events are tagged by fully reconstructing one of the B mesons, produced in pairs from $Υ(4S)$. The signal for $b \to u$ semileptonic decay is distinguished from the $b \to c$ semileptonic background using the hadronic and leptonic invariant mass distributions $M_X$ and $q^2$. We find the partial branching fraction for the kinematical region given by $M_X < 1.7 GeV/c^2$ and $q^2>8 …
Recent rate measurements of B_s mesons and Lambda_b baryons produced in sqrt{s} = 1.96 TeV proton-antiproton and Upsilon(5S) electron-positron collisions are reviewed, including the first observations of six new decay modes: B_s -> D_s^+ K^- (CDF), B_s -> D_s^- D_s^+ (CDF), B_s -> D_{s1}^-(2536) mu^+ nu_mu X (DZero), B_s -> phi gamma (Belle), Lambda_b -> p pi^- (CDF), and Lambda_b -> p K^- (CDF). Also examined are branching-fraction measurements or limits for the B_s -> D_s^{(*)} D_s^{(*)} modes (Belle, CDF, and DZero), the B_s -> gamma gamma radiative penguin decay (Belle), and three two-body…
We report measurements of branching fractions and CP asymmetries for $B \to ηK^*$ and $B \to ηρ$ decays. These results are obtained from a $414 {\rm fb}^{-1}$ data sample collected at the $Υ(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. We measure the following branching fractions: ${\mathcal B}(B^0 \to ηK^{*0}) = (15.2 \pm 1.2 \pm 1.0)\times 10^{-6}$ and ${\mathcal B}(B^+\toηK^{*+}) = (19.3^{+2.0}_{-1.9}\pm 1.5)\times 10^{-6}$, where the first error is statistical and the second systematic. We also find a $2.7σ$ excess in the $B^+\toηρ^+$ mode and me…
We report a search for the charmless vector-vector decay B0->omega K*0 with 520x10^6 BBbar pairs collected with the Belle detector at the KEKB e+e- collider. We measure the branching fraction in units of 10^-6: Br = 1.2 +0.9-0.8 +-0.2 (<2.7), where the first error is statistical, the second systematic, and the upper limit is at the 90% confidence level.
The Belle II experiment at the SuperKEKB energy-asymmetric $e^+e^-$ collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. The design luminosity of the machine is $8\times10^{35}\, \mathrm{cm}^{-2}\mathrm{s}^{-1}$ and the Belle II experiment aims to record $50\, \mathrm{ab}^{-1}$ of data, a factor of 50 more than its predecessor. From February to July 2018, SuperKEKB has completed a commissioning run, achieved a peak luminosity of $5.5 \times 10^{33}\, \mathrm{cm}^{-2}\mathrm{s}^{-1}$, and Belle II recorded a data sample of about $0.5\, \mathrm{fb}^{-1}$. I…
The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collider is a substantial upgrade of the B factory facility, Belle, at the Japanese KEK laboratory. The main operation of SuperKEKB has started in March 2019, and collisions ran until July 2019, achieving a peak luminosity of $5.5\times 10^{33}$ cm$^{-2}$s$^{-1}$. The results presented here were obtained from a subset of collected data of 0.41 fb$^{-1}$. In the poster presented at the conference the first results from studying semileptonic $\textit{B}$-meson decays were shown. The performance of the Full Event Interpretation …
We present a summary of the latest measurements of branching fractions and direct CP violations in the charmless hadronic two-body B decays B -> K^+ pi^-, K^+ pi^0, K^0 pi^+ and K^0 pi^0, performed by the Belle, BABAR, CDF and CLEO experiments. The interpretations and the future prospects about discrepancies, called "Kpi puzzle", between theoretical expectations and measurements are discussed.
