Radiative and electroweak penguin mediated decays of $B$ mesons are a great probe for physics beyond the Standard Model of particle physics. Furthermore, recently anomalies on exclusive $b \rightarrow s \ell^{+} \ell^{-}$ processes, which may imply lepton flavor universality violation, have been observed. Belle II experiment sheds light on the anomalies with the measurement of an inclusive analysis in this mode. Thanks to smaller hadronic uncertainties compared with exclusive modes, complementary information can be provided. Belle II is also a unique experiment to search for processes involving neutrinos such as $B \rightarrow K^{(*)} ν\overlineν$. We report the results and prospects of an inclusive $B \rightarrow X_s \ell^{+} \ell^{-}$ analysis and a search for $B \to K^{(*)} ν\overlineν$.
We present recent results for radiative and electroweak penguin decays of $B$ me son at Belle. Measurements of differential branching fraction, isospin asymmetr y, $K^*$ polarization, and forward-backward asymmetry as functions of $q^2$ for $B \to K^{(*)}ll$ decays are reported. For the results of the radiative process, we report measurements of branching fractions for inclusive $B\to X_s γ$ and the exclusive $B\to K η' γ$ modes.
We report searches for the radiative penguin decays Bs to phi gamma and Bs to gamma gamma based on a 23.6 fb-1 data sample collected with the Belle detector at the KEKB e+e- energy-asymmetric collider operating at the Upsilon(5S) resonance.
We summarise the most recent results of the Belle experiment about flavour changing neutral current (FCNC) radiative and (semi-) leptonic B decays. In particular, we report about the first observation of the decays B->K*l+l-, B->phi K gamma, the inclusive B->Xs l+l-$. We also report about searches for B->l+l- decay and for CP asymmetries in B->K*gamma.
We report the measurements of electroweak penguin processes b->d,s gamma and b->sl+l- at the Belle experiment. The analyses are based on 152 million BB-bar events collected at the Upsilon(4S) resonance with the Belle detector at the KEKB e+e- asymmetric-energy collider. The b->d gamma transition is studied through exclusive decays: B0->rho0 gamma, B0->omega gamma and B+ ->rho+ gamma. We apply fully inclusive and semi-inclusive reconstruction to b->s gamma and b->sl+l- processes, respectively. The results on the exclusive b->d gamma and semi-inclusive b->sl+l- measurements are preliminary.
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.
We present recent progresses in radiative penguin decays of $B$ meson using a large sample of $B\bar{B}$ pairs recorded at the $Υ(4S)$ resonance with the Belle detector at the KEKB asymmetric energy $e^+e^-$ collider. We report precise measurement of inclusive $b\to sγ$ branching ratio with cut $E_γ> 1.7$ GeV, first measurement of time-dependent CP-violation in $B^0\to K_sρ^0γ$, measurement of $B^+\to K^+η'γ$ branching fraction, and improved branching fraction results for $B^0\to(ρ,ω)γ$ with new CP and isospin violation results in the mode.
The $b\to s(d)$ quark-level transitions are flavor-changing neutral current processes, which are not allowed at tree level in the standard model. These processes are very rare and constitute a potential probe for new physics. Belle II at SuperKEKB is a substantial upgrade of the Belle experiment. It aims to collect 50 ab$^{-1}$ of data with a design peak luminosity of $8\times 10^{35}$ cm$^{-2}$s$^{-1}$ that is 40 times more than its predecessor. It has been recording data since 2019 and during these early days of the experiment, efforts are being made to detect early signals of the above deca…
We report on the results of penguin-mediated B decays at the Belle experiment. The analyses were based on approximately 32 million $B\bar{B}$ events collected at the $Υ(4S)$ resonance with the Belle detector at the KEKB $e^+e^-$ storage ring. The $b \to s γ$ transition was studied through exclusive decays: $B \to K^{*} γ$, $B^0 \to K_{2}^{*}(1430)^0 γ$, $B^+ \to K^+π^-π^- γ$, $B^+ \to K^{*0} π^+ γ$ and $B^+ \to K^+ρ^0 γ$. The $b \to s \ell^+ \ell^-$ transition was searched through both exclusive decays, $B \to K^{(*)} \ell^+ \ell^-$, and inclusive decay, $B \to X_{s} \ell^+ \ell^-$. We observe…
The Belle~II Collaboration presents four new analyses: The measurement of $V_{ub}$ from $B \to πe ν_e$ decays with a fit to the differential $q^2$ spectrum, the determination of $V_{cb}$ using a fit to the differential $w$ distribution from $B^0 \to D^{\ast -} \ell^+ ν_\ell$ decays, and the measurement of $q^2$ moments in inclusive $B \to X_c \ell ν_\ell$ decays. In all these analyses tag-side $B$ meson is reconstructed in a fully hadronic decay chain. The last result are branching fraction measurement of $B \to K^\ast \ell^+ \ell^-$ decays using an untagged approach.
We report on new results on $B \to K^* γ$ and recent studies on $B \to K^* \ell^+ \ell^-$ and $B \to h ν\barν$ at Belle at KEKB accelerator. All the analyses used full data sample of 711~fb${}^{-1}$ taken on $Υ(4S)$ resonance.
We report on the measurement of the decay $B\to K^{\star}γ$, lepton-flavor dependent angular analysis of the decay $B\to K^{\star}\ell\ell$, and search for the decays $B\to hνν$. All these analyses are performed on the 711 $fb^{-1}$ data sample recorded by the Belle detector at the $Υ(4S)$ resonance.
We search for the radiative penguin decays B_s to phi gamma and B_s to gamma gamma in a 23.6 fb-1 data sample collected at the Upsilon(5S) resonance with the Belle detector at the KEKB e+e- asymmetric-energy collider. We observe for the first time a radiative penguin decay of the B_s meson in the B_s to phi gamma mode. No significant B_s to gamma gamma signal is observed.
We present measurements on penguin dominated B decays which are sensitive to new physics, such as CP-violation parameters and branching fractions in $b \to s q\bar{q}$ and $b \to d q\bar{q}$ gluonic and radiative decays using a large sample of $B\bar{B}$ pairs recorded at the $Υ(4S)$ resonance with the Belle detector at the KEKB asymmetric energy $e^+e^-$ collider.
In this article, I review the most recent results in radiative penguin decays from the B factories Belle and Babar. Most notably, I will talk about the recent new observations in the decays B -> (rho/omega) gamma, a new analysis technique in b -> s gamma, and first measurements of radiative penguin decays in the B_s meson system. Finally, I will summarize the current status and future prospects of radiative penguin B physics at the B factories.
High precision measurements in the quark flavor sector are essential for searching for new physics beyond the Standard model. SuperKEKB collider and Belle II detector are designed to perform such measurements. The status and prospects of the SuperKEKB and Belle II are presented in this article.
The Belle II collaboration operates a substantially upgraded Belle detector at the SuperKEKB energy-asymmetric e+ e- collider. Belle II will start recording collisions at the Upsilon(4S) energy in 2018, aiming to collect by 2025 50 ab^{-1} of data, 50 times more than the Belle experiment. We report prospects for measuring quantities associated with charge-parity violation, with special emphasis on the Cabibbo-Kobayashi-Maskawa angle phi_3 (gamma) and observables in semileptonic B meson decays associated with the quark-mixing matrix element Vub.
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.
Recent branching fraction and asymmetry results of Electroweak Penguin B decays from BaBar, Belle and CLEO experiments are reviewed. While these branching fractions are consistent with the Standard Model expectations and are being used to extract heavy quark model parameters and CKM matrix elements, the asymmetry results are just becoming sensitive to observe any new physics effects.
Belle played a leading role in shaping the spectroscopy sector for last decade. With 50 times more data than Belle, the Belle II experiment also expects to play crucial role in spectroscopy for the next decade. In this talk, a few chosen results one expects from Belle II will be discussed.
$B$-meson decays involving radiative and electroweak penguin processes are sensitive probes to new physics beyond the standard model. The Belle experiment recently reported measurements of the inclusive radiative decay $B \to X^{}_{s} γ$, and exclusive radiative decays $B \to K^{\ast} γ$ and $B \to K^{0}_{S} ηγ$. A lepton-flavor dependent measurements of angular observables for the decays $B \to K^{\ast} \ell \ell$ by Belle hinted at possible deviation from lepton-flavor-universality. Any departure from lepton flavor universality is essentially accompanied by lepton flavor violation. Recently,…
Belle II has a broad $τ$ physics program, in particular in searches for lepton flavour and lepton number violations. Belle II profits from the relatively large $τ$-pair production rate in the low background environment of $e^+e^-$ -collisions at 10.58 GeV. Up to mid-2021 Belle II collected a sample corresponding to $214~\text{fb}^{-1}$ of data. We present a first measurement of the $τ$ mass, the prospects for the $τ$-lifetime measurement, and review the overall $τ$ lepton physics program of Belle II.
Belle II is an upcoming experiment at the next generation SuperKEKB e+e- collider. It will record about 50 ab-1 of data mostly at the Y(4S) resonance. The high statistics will allow precision measurements for rare decays, which can be then compared with the Standard Model predictions in order to search indirectly for new physics. We present the prospects for rare decay studies at Belle II.
The Belle II experiment at the SuperKEKB electron-positron collider will provide a large sample of charm mesons in addition to its primary goal of B meson production. The large data sample and wide variety of accessible D meson decay modes in a clean experimental environment provide sensitivity to new physics via D meson mixing and CP violation measurements. This contribution briefly describes selected components of the upgrade from Belle to Belle II and KEKB to SuperKEKB, and some prospects for new physics searches in the areas of charm mixing and CP violation.
The Belle II experiment is under construction at the KEK laboratory in Japan. Belle II will study e+e- collisions at or near the Upsilon(4S) resonance with the goal of collecting 50 ab-1 of data, which is a large increase over that recorded by the Belle and BaBar experiments. This data will provide a large sample of charm meson decays, and Belle II will have a very active charm physics program. Here we discuss some highlights of this program, focusing on measurements of mixing, CP violation, and leptonic decays.
The Belle II experiment is an upgrade of the Belle detector and will operate at the SuperKEKB energy-asymmetric $e^+e^-$ collider. The accelerator has already successfully completed the first phase of commissioning and first electron positron-collisions in Belle II were observed in April 2018. The design luminosity of SuperKEKB is 8x10$^{35}$ cm$^{-2}$s$^{-1}$ and the Belle II experiment aims to record 50 ab$^{-1}$ of data. Belle II has a broad program of $τ$ physics, in particular, precision measurements of Standard Model parameters and searches of lepton flavor and lepton number violations, …
Belle II is a major upgrade of the Belle experiment and will operate at the $B$-factory SuperKEKB in Japan. Here we discuss the expected sensitivity of Belle II for $D^0 - \bar{D}^0$ mixing and $CP$ violation measurements in the charm sector, which will benefit from a factor 50 increase in statistics and an improved vertex detection and particle identification. The impact on the determination of CKM parameters from the measurements of purely leptonic $D$ mesons decays is discussed. Finally a novel method of flavour tagging to substantially increase the sample of $D^0$ and $\bar{D}^0$ is presen…
The Belle II experiment is under construction at the KEK laboratory in Japan. Belle II will study e+e- collisions at or near the Upsilon(4S) resonance with the goal of collecting 50 ab-1 of data, which is a large increase over that recorded by the Belle and BaBar experiments. This data will provide a large sample of charm meson decays. In this report we present the expected sensitivity of Belle II for measuring time-dependent mixing and CP violation in the D0-D0bar system. We focus on measurements of D0-> K+ pi-, D0-> K+ pi- pi0, and D0-> K0_S pi+ pi- decays.
B physics results from the Belle experiment are reviewed. Precise measurements of Cabbibo-Kobayashi-Maskawa matrix elements are made. Several decay modes are observed which will enable us to measure the CP angles, phi_i in channels other than B0->psi K0 modes. New rare decay modes are observed in many channels. Particular attention is paid to the first observation of the electroweak penguin-mediated decay.
Rare and flavour-changing neutral current decays of the B meson are an important probe in the search for physics beyond the Standard Model. There have recently been several anomalies in rare B decays, and lepton-universality measurements, specifically involving the $b\to s\ell^+\ell^-$ quark transition. These results tend towards a non-Standard-Model interpretation. The Belle II experiment is a next-generation b physics experiment located at SuperKEKB, an upgraded B factory $e^+e^-$ collider, in Tsukuba, Japan. The first collisions are expected in early 2018 with full physics data expected in …
We present an improved measurement of the branching fraction for the electroweak penguin process B->Xsl+l-, where l is an electron or a muon and Xs is a hadronic system containing an s-quark. The measurement is based on a sample of 152 * 10^6 ~ Upsilon(4S) -> BB-bar events collected with the Belle detector at the KEKB e+e- asymmetric-energy collider. The Xs hadronic system is reconstructed from one K+- or K0s and up to four pions, where at most one pion can be neutral. Summing over both lepton flavors, the inclusive branching fraction is measured to be Br(B->Xsll)=(4.11 +- 0.83(stat.) +0.74 -0…
We report the first measurement of the branching fraction for the inclusive decay B --> X(s) l+ l-, where l is either an electron or a muon and X(s) is a hadronic recoil system that contains an s-quark. We analyzed a data sample of 65.4 * 10**6 B meson pairs collected with the Belle detector at the KEKB e+e- asymmetric-energy collider. We find Br(B --> X(s) l+ l-) = (6.1 +/-1.4(stat) +1.4-1.1(syst)) * 10**(-6) for dilepton masses greater than 0.2 GeV/c**2.
The Belle II experiment is a substantial upgrade of the Belle detector and will operate at the SuperKEKB energy-asymmetric $e^+e^-$ collider. The design luminosity of the machine is 8$\times10^{35}$ cm$^{-2}$s$^{-1}$ and the Belle II experiment aims to record 50 ab$^{-1}$ of data, a factor of 50 more than its predecessor. From February to July 2018, the machine has completed a commissioning run and main operation of SuperKEKB has started in March 2019. Belle II has a broad $τ$ physics program, in particular in searches for lepton flavor and lepton number violations (LFV and LNV), benefiting fr…
This article gives an overview of the recent searches and measurements of $b\to d$ penguin transitions with the BaBar experiment. The branching fraction of these decays in the Standard Model (SM) is expected to be a factor of 10 or more lower than the corresponding $b\to s$ penguin transitions, but a deviation from the SM prediction would be an equally striking sign of new physics. The exclusive decay $B\toπ\ell\ell$ is searched by BaBar with no excess over the background found. The BaBar measurement of $B\to(ρ,ω)γ$ provides the first evidence of $B^+\toρ^+γ$, is in good agreement with the pre…
We present an improved measurement of the branching fraction for the electroweak penguin process B->Xsll, where l is an electron or a muon and Xs is a hadronic system containing an s-quark. The measurement is based on a sample of 152*10^6 Upsilon(4S) -> BB events collected with the Belle detector at the KEKB energy asymmetric e+e- collider. The Xs hadronic system is reconstructed from one K^{+-} or K^{0}_{S} and up to four pions, where at most one pion can be neutral. Averaging over both lepton flavors, the inclusive branching fraction is measured to be Br(B->Xsll)=(4.11+-0.83(stat)+0.85-0.81(…
The Belle II experiment at the SuperKEKB asymmetric $e^+e^-$ collider at KEK, Tsukuba, Japan, is recording data since 2018. The expected high luminosity of $\mathcal{L}=8\cdot 10^{35}~$cm$^{-2}$s$^{-1}$ enables searches for yet unobserved exotic hadronic states in B meson decays. We describe the search for a partner state of the $X(3872)$ at the $D^{*}\bar{D}^{*0}$ threshold. The reconstruction of charmed mesons is tested with experimental data corresponding to an integrated luminosity of $504~$pb$^{-1}$ collected at the energy in the center of mass of $Υ(4S)$ in 2018, and $2.62~$fb$^{-1}$ in …
We report recent results obtained with the Belle detector using a 23.6 fb^{-1} data sample collected on the Y(5S) resonance at the KEKB asymmetric energy e^+ e^- collider. Inclusive semileptonic B_s^0 -> X^+ l^- νdecays are studied for the first time and the branching fraction is measured. Combining the electron and muon channels, we obtain Bf(B_s^0 -> X^+ l^- ν) = (10.2 \pm 0.8 \pm 0.9)%. Also, the radiative penguin decay B_s^0 -> ϕγis observed for the first time, and an improved upper limit for the decay B_s^0 \to γγis obtained.
In this proceeding, we report the recent measurements of time-dependent CP violation in B meson decays from the Belle Collaboration. The Belle experiment stopped operation in June 2010 and collected nearly 772 x 10^6 B B-bar pairs at the Υ(4S) resonance at the KEKB asymmetric-energy e^+e^- collider. We used this full data sample to measure the CP violation parameters in b->c c-bar s and b->c c-bar d decays. We also report new measurements of CPT violation parameters in B decays. Furthermore, we report the first observation of a new b->s radiative penguin decay B^0->ϕK^0 γ, as well as measureme…
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.
Penguin, or loop, decays of B mesons induce effective flavor-changing neutral currents, which are forbidden at tree level in the Standard Model. These decays give special insight into the CKM matrix and are sensitive to non-standard model effects. In this review, we give a historical and theoretical introduction to penguins and a description of the various types of penguin processes: electromagnetic, electroweak, and gluonic. We review the experimental searches for penguin decays, including the measurements of the electromagnetic penguins b -> s gamma and B -> K* gamma and gluonic penguins B -…
Time dependent CP-violation phenomena are a powerful tool to precisely measure fundamental parameters of the Standard Model and search for New Physics. 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 $8\times{10}^{35}~cm^{-2}s^{-1}$ and the Belle II experiment aims to record $50~ab^{-1}$ of data, a factor of 50 more than its predecessor. From February to July 2018, the machine has completed a commissioning run, achieved a peak luminosity of $5.…
The Belle II experiment at the SuperKEKB energy-asymmetric $e^+e^-$ collider is a substantial upgrade of the B factory facility at KEK in Tsukuba, Japan. It aims to record a factor of 50 times more data than its predecessor. The experiment completed a commissioning run in 2018, and began full operation in early 2019. Belle II is uniquely capable of studying the so-called XYZ particles: heavy exotic hadrons consisting of more than three quarks. First discovered by Belle, these now number in the dozens, and represent the emergence of a new category within quantum chromodynamics. This talk will p…
In this report, experimental prospects for the inclusive analysis of the radiative B decays and electroweak penguin decays at the super B factories are presented.
The huge datasets collected at the two B factories, Belle and BaBar, have made it possible to explore the radiative penguin process b --> s gamma, the electroweak penguin process b --> s l+ l- and the suppressed radiative process b --> d gamma in detail, all in exclusive channels and inclusive measurements. Theoretical tools have also advanced to meet or surpass the experimental precision, especially in inclusive calculations and the various ratios of exclusive channels. In this article, we review the theoretical and experimental progress over the past decade in the radiative and electroweak p…
High-precision flavor physics measurements play a complementary role to the direct searches for new physics by CMS and ATLAS experiments at LHC. Such measurements will be performed with the Belle II detector at the upgraded KEKB accelerator (SuperKEKB) in Japan. The physics potential with emphasis on the charm sector, current status and future prospects of the Belle II experiment are presented in these proceedings.
We report a search for the flavor-changing neutral current decay $B \to X_{s} \ell^{+} \ell^{-}$ using a 29.5 fb$^{-1}$ data sample accumulated at the $Υ(4S)$ resonance with the Belle detector at the KEKB $e^{+}e^{-}$ storage ring. We observe evidence for $B\to Kμ^+μ^-$ and report the preliminary branching fraction of ${\cal B}(B \to K μ^{+} μ^{-}) = (0.99^{+0.39}_{-0.32}^{+0.13}_{-0.15}) \times 10^{-6}$. We also set the following 90% confidence level upper limits on the branching fractions for exclusive and inclusive decays, ${\cal B}(B \to K e^{+} e^{-}) < 1.2 \times 10^{-6}$, ${\cal B}(B \t…
We study glueball G production in gluonic penguin decay B -> X_s G, using next-to-leading order b -> s g^* gluonic penguin interaction and an effective coupling of a glueball to two gluons. The effective coupling allows us to study the decay rate of a glueball to two pseudoscalars in the framework of chiral perturbation theory. Identifying the f_0(1710) to be a scalar glueball, we then determine the effective coupling strength with the branching ratio of f_0(1710) -> K KBar. We find that the charm penguin to be important and obtain a sizable branching ratio for Br(B -> X_s G) in the range of (…
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-…
