Semileptonic decays of charged and neutral $B$ mesons play a critical role in the determination of the magnitudes of the CKM-matrix elements $V_{cb}$ and $V_{ub}$, and in the test of the lepton universality which is a basic assumption of the Standard Model. Due to the missing neutrino in the semileptonic decays, the measurements depend strongly on the tag efficiency of the $B$ meson in the recoil side which is at a few per mille to a few per cent level, and this values a limiting factor for high precision measurement and high sensitivity test mentioned above. We develop a novel method of reconstructing semileptonic decays of the $B$ mesons by introducing the $B$ momentum information calculated from the $B$ decay vertex and the interaction point, as well as the kinematic information of $e^{+}e^{-}\to B\overline{B}$ at the $B$-factories such as BaBar, Belle, and Belle II. As this method does not depend on the reconstruction of the $B$ meson in the recoil side, the gain in the efficiency could be as large as two orders of magnitudes. This makes high precision measurement of CKM-matrix elements $|V_{cb}|$ and $|V_{ub}|$ and high precision test of lepton universality at $B$-factories more promising. We present the algorithms for the semileptonic decays of neutral and charged $B$ mesons separately, as they are affected by the magnetic field in the detector differently.
Top partner searches are one of the key aspects of new physics analyses at the LHC. We correct an earlier statement that supersymmetric top searches based on decays to semileptonic tops are not promising. Reconstructing the direction of the boosted leptonic top quark and correlating it with the measured missing transverse energy vector allows us to reduce the top pair background to an easily manageable level. In addition, reconstructing the full momentum of the leptonic top quark determines the stop mass based on an M_{T2} endpoint.
Semileptonic decays of B mesons may be used in many different ways to probe the CKM matrix. Presented here are several recent results from the CLEO II experiment, all involving the analysis or utilization of semileptonic B decays.
We present two topics on charm meson semileptonic decay. Evidence for interference in the decay K*munu and new results on the D+ to K*munu/K2pi branching fraction.
Study of semileptonic decays of neutral kaons allows to perform a test of discrete symmetries, as well as basic principles of the Standard Model. In this paper a general review on dependency between charge asymmetry constructed for semileptonic decays of short- and long-lived kaons and $\mathcal{CPT}$ symmetry is given.
Recent results on inclusive and exclusive semileptonic B decays from B Factories are presented. The status and perspectives of the determination of the CKM matrix elements Vub and Vcb with semileptonic B decays is discussed.
The present status of the measurement of the semileptonic B decays is reviewed. Emphasis is given on the factors affecting experimental errors of the Cabibbo-Kobayashi-Masawa matrix element |Vcb | and |Vub |.
Recent semileptonic D meson decay results are summarized, including the improved measurements of absolute branching fractions for exclusive D0 semileptonic decays into $K^{-}e^{+}ν$, $π^{-}e^{+}ν$ and $K^{*-}e^{+}ν$, and the first observation and absolute branching fraction measurement of $D^{0} \to ρ^{-}e^{+}ν$ with the first CLEO-c data sample.
Studies of semileptonic $B_s$ decays by the Belle, Babar and D0 experiments are reported. In particular measurements of inclusive semileptonic $B_s$ decays by Belle and Babar and the exclusive excited charm mode $B_s \to D_{s1} μν$ from D0 are presented. An outlook on further semileptonic $B_s$ measurements with $Υ(5S)$ data at Belle and Belle II is also given.
The recent experimental results on leptonic $D^+_{(s)}$ decays, semileptonic $D$ decays, determinations of decay constants and form factors, as well as extractions of $|V_{cd}|$ and $|V_{cs}|$ are briefly reviewed. Global analysis of all existing measurements of leptonic $D^+_{(s)}$ decays and semileptonic $D$ decays yields $|V_{cd}|=0.2157\pm 0.0045$ and $|V_{cs}|=0.983\pm 0.011$, which are the most precision determinations of these two CKM matrix elements up to date.
Experimental results for the pseudoscalar decay constants f_{D} and f_{D_s} are reviewed. Semileptonic form factor results from D -> (pseudoscalar) l nu and D -> (vector) l nu decays are also reviewed.
We review the recent results on D and Ds meson semileptonic decays from CLEO-c. Comparisons with lattice quantum chromodynamics (LQCD) calculations and implications for B physics are also discussed.
BaBar measurements involving semileptonic decays of B mesons are reviewed. Attention is focused on the extraction of |Vub| and |Vcb| elements of the Cabibbo-Kobayashi-Maskawa quark mixing matrix. Recent results of inclusive and exclusive approaches are presented.
Studies of semileptonic decays of b hadrons with the LHCb experiment are reported. In particular, measurements of the b hadron production fractions at the LHC and Bs semileptonic decays in P-wave charmed mesons are presented. An outlook of the LHCb potential in measuring the CKM matrix elements Vub and Vcb, as well as decays involving taus, is given.
This paper gives an experimental overview of current status and open questions on charm lifetimes and semileptonic decays, the latter including new results presented by E687 and CLEO at this Conference.
We report the result of a search for D0 - D0_bar mixing in the data from hadroproduction experiment E791 at Fermilab. We use the D* tag and semileptonic decay vertices of D0 to look for wrong-sign decays with mixing time dependence.
The present status of the measurement of the inclusive semileptonic $B$ decays is reviewed. In particular the determination of the Cabibbo-Kobayashi-Maskawa matrix elements $|V_{cb}|$ and $|V_{ub}|$ is discussed and some future prospects are given.
Using e+e- collision data in the sqrt{s} = 4 GeV energy region, CLEO-c has made extensive studies of semileptonic and leptonic decays of the D0, D+, and Ds+ charmed mesons. We report recent measurements of absolute branching fractions, form factors, and decay constants that serve as precision tests of theoretical calculations.
Recent measurements of branching fractions, form factors and decay constants of leptonic and semileptonic decays of D_(s)-mesons acquired at experiments running at the Upsilon(4S) resonance energy are reviewed.
We present measurements of the inclusive semileptonic branching fractions of charged and neutral B mesons using 20.6 fb-1 of data measured at the Upsilon(4S) with the BABAR detector. Events are tagged with a fully reconstructed hadronic decay of a B meson. The correlation between the flavor of the tag B meson and the electron charge allows the separation of prompt semileptonic B decays and cascade semileptonic charm decays. We obtain the preliminary inclusive semileptonic branching fraction of charged B mesons b+ = 0.103+/-0.006+/-0.005, neutral B mesons b0 = 0.104+/-0.008+/-0.005, their avera…
Some recent Babar results on semileptonic decays are presented. They focus on the determination of the CKM matrix elements |V_{ub}| and |V_{cb}| in inclusive and exclusive b --> u l nu and b--> c l nu decays, and on form factors measurement in exclusive c--> s l nu decays.
Precision results on the leptonic, semileptonic, and hadronic decays of charm mesons are reviewed. These results are important for timely progress in weak flavor physics both in their own right and as checks of theoretical calculations. Recent years have seen much progress on weak decays of charm, in both theory and experiment, a trend we expect to continue.
We review the current status of experimental measurements of the branching fractions for exclusive semileptonic decays of B mesons to charmless hadrons and the determination of the Standard Model CKM parameter |Vub| from these measurements.
We report on recent measurements of hadronic, semileptonic and leptonic $D$ decays taken using ~57 pb^-1 of data collected on the psi'' resonance using the CLEO-c detector.
Several high energy experiments have been actively pursuing the analyses of semileptonic decays of charm mesons, resulting in numerous new results and publications. In this report, we summarize the recent efforts on the topics of pseudoscalar and vector charm semileptonic decays, especially in the area of branching fractions and form factor measurements.
Semileptonic decays of the B mesons provide an excellent probe for the weak and strong interactions of the bottom quark. The large data samples collected at the B Factories have pushed the experimental studies of the semileptonic B decays to a new height and stimulated significant theoretical developments. I review recent progresses in this fast-evolving field, with an emphasis on the determination of the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element |Vub|.
We summarize recent data on 4-body charm semileptonic decay concentrating on \kklndk{} and \kpilndk{}. We begin with giving some motivation for the study of these decays. We discuss several of the models traditionally used to describe these decays and conclude by presenting a non-parametric analysis of \kpiendk{} and its possible extension into non-parametric studies of \kpimndk{}.
A review of charm semileptonic decays results obtained at B factories is presented. It focuses on form factors measurements in $D^0\to K^- \ell^+ ν$, $D^0\to π^- \ell^+ ν$, $D_s^+ \to K^+K^- e^+ν_e$, and $D^+ \to K^-π^+ e^+ν_e$. For the last two decay channels, the contribution and characteristics of other components in the final state, in addition to the main vector contribution, is also studied.
We review the recent results on D and D_s meson semileptonic decays from CLEO-c, BABAR, and Belle. Comparisons with lattice quantum chromodynamics (LQCD) calculations and implications for B physics are also discussed.
This paper presents the analysis of leptonic and semileptonic kaon decays data done by the FlaviaNet Kaon Working group. Data include all recent results by BNL-E865, KLOE, KTeV, ISTRA+, and NA48. Experimental results are critically reviewed and combined, taking into account theoretical (both analytical and numerical) constraints on the semileptonic kaon form factors. We report on a very accurate determination of V_{us} as well as on many other tests of the SM which can be performed with leptonic and semileptonic K decays.
Study of semileptonic decays of neutral kaons allows to perform a test of discrete symmetries, as well as basic principles of the Standard Model. In this paper a general review on dependency between charge asymmetry constructed for semileptonic decays of short- and long-lived kaons and CPT symmetry is given. The current status of determination of charge asymmetry for short-lived kaon, obtained by reconstruction of about 10^5 KS -> pen decays collected at DAFNE with the KLOE detector is also reviewed.
We present results on semileptonic B decays obtained with the BABAR detector. The large data set accumulated at the PEP-II asymmetric-energy B-Factory allows a new measurement technique, where the hadronic decay of one B meson is fully reconstructed and the semileptonic decay of the recoiling B meson is studied. Traditional analysis techniques of inclusive and exclusive B decays complement this approach with very high statistics data samples. These measurements play an important role in the tests of the description of CP violation in the Standard Model: The determinations of the Cabibbo-Kobaya…
We present the first evidence for B semileptonic decays into the charmed baryon Lambda_c+ based on 420 fb-1 of data collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II e+e- storage rings. Events are tagged by fully reconstructing one of the B mesons in a hadronic decay mode. We measure the relative branching fraction BF(Bbar -> Lambda_c+ X l- nubar_l)/BF(Bbar -> Lambda_c+/Lambda_c- X) = (3.2 +/- 0.9_stat +/- 0.9_syst)%. The significance of the signal including the systematic uncertainty is 4.9 standard deviations.
Using the CLEO II.V detector observing e+e- collisions at around 10.6 GeV we search for neutral D mixing in semileptonic D0 decays tagged in charged D* decays. Combining the results from the Kenu and K*enu channels we find that the rate for D mixing is less than 0.0078 at 90% C.L.
We begin with giving some motivation for the study of charm semileptonic and fully leptonic decays. We turn next to a discussion of semileptonic absolution branching fraction results form CLEO-c. Two exciting high statistics results on fully leptonic decays of the D+ -> mu+ nu and Ds+ -> mu+ nu from CLEO-c and BaBar are reviewed. We turn next to a discussion of recent results on charm meson decay to pseudo-scalar l nu decays from FOCUS, BaBar, and CLEO-c. We conclude with a review of charm meson decay into Vector l nu.
LHCb has recorded large samples of semileptonic {\textit B} decays. These provide the possibility to study {\textit CP} violation effects in the $B^{0}_s$ and $B^{0}$ systems. Decay-time-integrated or decay-time-dependent asymmetries between charge conjugated final states probe {\textit CP} violation in $B^{0}_{(s)}$ mixing through the measurement of the parameter $a_{\textrm sl}. These measurements rely on data-driven techniques to control possible detection asymmetries.
In this paper, we review recent progress in the field of semileptonic decays of charm mesons, including topics on the relative branching ratio and the form factors. The comparison between the experimental form factor measurements and the Lattice QCD calculations is emphasized.
We report a measurement of the inclusive electron energy spectrum for semileptonic decays of B mesons in a 140 fb^-1 data sample collected near the Upsilon(4S) resonance, with the Belle detector at the KEKB asymmetric energy e^+ e^- collider. We determine the first and second moments of the spectrum for threshold values of the electron energy between 0.6 and 1.5 GeV.
We review recent experimental progress in the domain of rare radiative, semileptonic and leptonic B decays. The statistical precision attained for these decays has reached a level where they start to impose meaningful constraints on the Cabibbo-Kobayashi-Maskawa matrix, which are complementary to those obtained from hadronic decays. While the current data indicate no deviations from Standard Model predictions, there is still some room for new physics in these decays.
Recent analyses of the LEP and Y(4S) data have better outlined the picture of semileptonic B decays. Results on inclusive and exclusive decay branching fractions and on the extraction of the Vub and Vcb elements of the CKM mixing matrix are discussed, together with some of the still open questions and the sources of model systematics.
We present a search for anomalous semileptonic decays of heavy flavor hadrons produced in association with a $W$ boson, in proton-antiproton collisions at sqrt{s}=1.96 TeV. We use 162 pb-1 of data collected with the CDF II detector at the Fermilab Tevatron Collider. We select events with one W boson and at least one jet with an identified secondary vertex. In the jets with a secondary vertex we look for a semileptonic decay to a muon. We compare the number of jets with both a secondary vertex and a semileptonic decay, and the kinematic properties of these jets, with the standard model expectat…
The new results of investigation of K^0_Le3 and K^{\pm}e3 decays performed by NA48 Collaboration are presented. The measured branching fractions are used to extract Vus. The values of Ke3 form-factors and radiative K^0_Le3γbranching ratio are reported. A list of recent NA48 results concerning some rare neutral kaon decays is given.
We discuss the impact of recent progress in semileptonic D decays on light flavour spectroscopy and estimate mixing parameters in the eta-eta^prime system.
Leptonic and semileptonic decays in the charm sector have been well studied in recent years. With the largest data sample near $D\bar D$ threshold, precision measurements of leptonic and semileptonic decays of charm meson and baryon are perfromed at BESIII. Test for letpon flavor universality is also performed. Sensitivity for rare leptonic and semileptonic charm decays is significantly improved taking advantage of the huge statistics in LHCb and the $B$ factories.
We compute the $O(α_s)$ corrections to the Wilson coefficient of the chromomagnetic operator in inclusive semileptonic B decays. The results are employed to evaluate the complete $O(α_s Λ^2/m_b^2)$ correction to the semileptonic width and to the first moments of the lepton energy distribution.
We search for signals of Weak Annihilation in inclusive semileptonic D decays. We consider both the widths and the lepton energy moments, which are quite sensitive probes. Our analysis of Cleo data shows no clear evidence of Weak Annihilation, and allows us to put bounds on their relevance in charmless B semileptonic decays.
We review measurements of semileptonic and leptonic charm meson decays performed by the Belle experiment, and we use these results to estimate the sensitivity of the follow-on Belle II experiment to these decays.
Existing analyzes of baryon semileptonic decays indicate the presence of a small SU(3) symmetry breaking in hyperon semileptonic decays, but to provide evidence for SU(3) symmetry breaking, one would need a relation similar to the Gell-Mann Okubo(GMO) baryon mass formula which is satisfied to a few percents, showing evidence for SU(3) symmetry breaking in the divergence of the vector current matrix element. In this paper, we shall present a similar GMO relation for the hyperon semileptonic decay axial vector form factors. Using these relations and the measured axial vector current to vector cu…
The following is an overview of the current status of charmless semileptonic B decays and the extraction of the CKM matrix element $|V_{ub}|$ by the Belle and BaBaR collaborations.
Semileptonic B and D decays are on a well deserved podium to extract CKM matrix elements, to validate theoretical tools and, more recently, even to look for hints of new physics. Here we review the latest updates.
We review recent experimental and theoretical developments in inclusive semileptonic B -> Xc l nu decays. In particular, we discuss the determination of |Vcb| and of the heavy quark masses through fits based on the Operator Product Expansion.
Semileptonic decays of the $Ξ_b$ baryon are studied in the framework of the relativistic quark-diquark model based on the quasipotential approach. The weak decay form factors are calculated with the comprehensive account of all relativistic effects without employing nonrelativistic and heavy quark expansions. On this basis differential and total decay rates as well as different asymmetry parameters are calculated for the heavy-to-heavy $Ξ_b\to Ξ_c\ellν_\ell$ and heavy-to-light $Ξ_b\to Λ\ellν_\ell$ semileptonic decays. Predictions for the ratios of such decays involving $τ$ lepton and muon are …
Assuming $D^*_{sJ}(2317)$ and $D_{sJ}(2460)$ to be the $(0^+,1^+)$ chiral partners of regular $D_{s}(1968)$ and $D^{*}_{s}(2112)$, we calculate the semileptonic decays of $B_s$ to $D_s(1968)$, $D^*_s(2112)$, $D_{sJ}^{*}(2317)$, $D_{sJ}(2460)$ in terms of the Constituent Quark Meson (CQM) model. The large branching ratios of the semileptonic decays of $B_s$ to $D_{sJ}^{*}(2317)$ and $D_{sJ}(2460)$ indicate that those two semileptonic decays should be seen in future experiments.
Existing analyzes of baryon semileptonic decays indicate the presence of a small SU(3) symmetry breaking in hyperon semileptonic decays, but to provide evidence for SU(3) symmetry breaking, one would need a relation similar to the Gell-Mann--Okubo (GMO) baryon mass formula which is satisfied to a few percents, showing evidence for a small SU(3) symmetry breaking effect in the GMO mass formula. In this talk, I would like to present a similar GMO relation obtained in a recent work for hyperon semileptonic decay axial vector current matrix elements. Using these generalized GMO relations for the m…
Stimulated by recent observations of the excited bottom-strange mesons $B_{s1}$ and $B_{s2}^*$, we calculate the semileptonic decays $B_{s0}, B_{s1}^{\prime}, B_{s1}, B_{s2}^*\to [D_s(1968), D_{s}^*(2112), D_{sJ}(2317), D_{sJ}(2460)]\ell\barν$, which is relevant for the exploration of the potential of searching these semileptonic decays in experiment.
Some long-standing problems in the experimental data for semileptonic b -> c l nu decay rates have resisted attempts to resolve them, despite substantial efforts. We summarize the issues, and propose a possible resolution, which may alleviate several of these tensions simultaneously, including the "1/2 vs. 3/2 puzzle" and the composition of the inclusive decay rate in terms of exclusive channels.
