Measurement Of Branching Fraction Research Articles

Measurement of branching fraction and final-state asymmetry for the B¯0→KS0K∓π± decay

We report a measurement of the branching fraction and final-state asymmetry for the $\bar{B}^{0}\to K^{0}_{S}K^{\mp}\pi^{\pm}$ decays. The analysis is based on a data sample of 711 $\rm{fb}^{-1}$ collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. We obtain a branching fraction of $(3.60\pm0.33\pm0.15)\times10^{-6}$ and a final-state asymmetry of $(-8.5\pm8.9\pm0.2)\%$, where the first uncertainties are statistical and the second are systematic. Hints of peaking structures are seen in the differential branching fractions measured as functions of Dalitz variables.

Amplitude analysis and branching fraction measurement of D0→K−π+π0π0

Utilizing the dataset corresponding to an integrated luminosity of $2.93$ fb$^{-1}$ at $\sqrt{s}=3.773$ GeV collected by the BESIII detector, we report the first amplitude analysis and branching fraction measurement of the $D^0\rightarrow K^-\pi^+\pi^0\pi^0$ decay. We investigate the sub-structures and determine the relative fractions and the phases among the different intermediate processes. Our results are used to provide an accurate detection efficiency and allow measurement of ${\cal B}(D^0\rightarrow K^-\pi^+\pi^0\pi^0) \,=\, (8.86 \pm 0.13(\text{stat}) \pm 0.19(\text{syst}))\%$.

Lambda _b decays into Lambda _c^*ell bar{nu }_ell and Lambda _c^*pi ^-[Lambda _c^*=Lambda _c(2595) and Lambda _c(2625)] and heavy quark spin symmetry

We study the implications for Lambda _b rightarrow Lambda _c^*ell bar{nu }_ell and Lambda _b rightarrow Lambda _c^*pi ^-[Lambda _c^*=Lambda _c(2595) and Lambda _c(2625)] decays that can be deduced from heavy quark spin symmetry (HQSS). Identifying the odd parity Lambda _c(2595) and Lambda _c(2625) resonances as HQSS partners, with total angular momentum–parity j_q^P=1^- for the light degrees of freedom, we find that the ratios Gamma (Lambda _brightarrow Lambda _c(2595)pi ^-)/Gamma (Lambda _brightarrow Lambda _c(2625)pi ^-) and Gamma (Lambda _brightarrow Lambda _c(2595) ell bar{nu }_ell )/ Gamma (Lambda _brightarrow Lambda _c(2625) ell bar{nu }_ell ) agree, within errors, with the experimental values given in the Review of Particle Physics. We discuss how future, and more precise, measurements of the above branching fractions could be used to shed light into the inner HQSS structure of the narrow Lambda _c(2595) odd-parity resonance. Namely, we show that such studies would constrain the existence of a sizable j^P_q=0^- component in its wave-function, and/or of a two-pole pattern, in analogy to the case of the similar Lambda (1405) resonance in the strange sector, as suggested by most of the approaches that describe the Lambda _c(2595) as a hadron molecule. We also investigate the lepton flavor universality ratios R[Lambda _c^*] = mathcal{B}(Lambda _b rightarrow Lambda _c^* tau ,bar{nu }_tau )/mathcal{B}(Lambda _b rightarrow Lambda _c^* mu ,bar{nu }_mu ), and discuss how R[Lambda _c(2595)] may be affected by a new source of potentially large systematic errors if there are two Lambda _c(2595) poles.

Study of the decay K^{+}rightarrow pi ^{+}pi ^{-}pi ^{+}gamma in the OKA experiment

A high statistics data sample of the decays of K^+ mesons to three charged particles was accumulated by the OKA experiment in 2012 and 2013. This allowed to select a clean sample of about 450 events with K^{+}rightarrow pi ^{+}pi ^{-}pi ^{+}gamma decays with the energy of the photon in the kaon rest frame greater than 30 MeV. The measured branching fraction of the K^{+}rightarrow pi ^{+}pi ^{-}pi ^{+}gamma , with E_{gamma }^{*} > 30 hbox {MeV} is equal to (0.71 pm 0.05) times 10^{-5}. The measured differential branching fraction over photon energy is compared with the prediction of the chiral perturbation theory to {mathcal {O}}(p^{4}). A search for an up-down asymmetry of the photon with respect to the hadronic system decay plane is also performed.

Transition Probabilities of Sc i and Sc ii and Scandium Abundances in the Sun, Arcturus, and HD 84937

Abstract New branching fraction (BF) measurements for lines of Sc i and Sc ii from 24 Fourier transform spectra calibrated using standard lamps and the Ar branching ratio method are reported. The BFs for 259 lines are converted to absolute atomic transition probabilities using published radiative lifetimes from laser-induced fluorescence measurements. Detailed comparison to earlier published BF measurements corroborates most of the earlier results, with the exception of the yellow-line multiplet of Sc ii near 17,500 cm−1 or ≈5700 Å. The BFs of lines in this multiplet are found to be systematically too small by several error bars in earlier research. These new lab data on Sc, as well as recent hyperfine-structure studies, are applied to determine the abundance of scandium in the Sun, Arcturus, and HD 84937. General agreement is found with previous scandium abundance determinations in these stars. New consideration of scandium in metal-poor stars confirms that Sc abundances are correlated with Ti and V abundances.

Measurements of radiative lifetimes, branching fractions, transition probabilities, and oscillator strengths for Eu II and Eu III levels

Measurements of radiative lifetimes, branching fractions, transition probabilities, and oscillator strengths for Eu II and Eu III levels

First Measurements of Absolute Branching Fractions of the Ξ_{c}^{0} Baryon at Belle.

We present the first measurements of absolute branching fractions of Ξ_{c}^{0} decays into Ξ^{-}π^{+}, ΛK^{-}π^{+}, and pK^{-}K^{-}π^{+} final states. The measurements are made using a dataset comprising (772±11)×10^{6} BB[over ¯] pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB e^{+}e^{-} collider. We first measure the absolute branching fraction for B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0} using a missing-mass technique; the result is B(B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0})=(9.51±2.10±0.88)×10^{-4}. We subsequently measure the product branching fractions B(B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0})B(Ξ_{c}^{0}→Ξ^{-}π^{+}), B(B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0})B(Ξ_{c}^{0}→ΛK^{-}π^{+}), and B(B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0})B(Ξ_{c}^{0}→pK^{-}K^{-}π^{+}) with improved precision. Dividing these product branching fractions by the result for B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0} yields the following branching fractions: B(Ξ_{c}^{0}→Ξ^{-}π^{+})=(1.80±0.50±0.14)%, B(Ξ_{c}^{0}→ΛK^{-}π^{+})=(1.17±0.37±0.09)%, and B(Ξ_{c}^{0}→pK^{-}K^{-}π^{+})=(0.58±0.23±0.05)%. For the above branching fractions, the first uncertainties are statistical and the second are systematic. Our result for B(Ξ_{c}^{0}→Ξ^{-}π^{+}) can be combined with Ξ_{c}^{0} branching fractions measured relative to Ξ_{c}^{0}→Ξ^{-}π^{+} to yield other absolute Ξ_{c}^{0} branching fractions.

Measurement of the spectral function for the $τ^-\to K^-K_Sν_τ$ decay in BABAR experiment

The decay \mathbf{\tau^{-}\to K^{-}K_S\nu_{\tau}}𝛕−→𝐊−𝐊𝐒𝛎𝛕 has been studied using \mathbf{430\times10^6 ~ e^+e^-\to \tau^+\tau^-}430×106𝐞+𝐞−→𝛕+𝛕− events produced at a center-of-mass energy around 10.6 GeV at the PEP-II collider and studied with the BABAR detector. The mass spectrum of the \mathbf{K^{-}K_S}𝐊−𝐊𝐒 system has been measured and the spectral function has been obtained. The measured branching fraction \mathbf{{\cal B}(\tau^{-}\to K^{-}K_S\nu_{\tau})= (0.739\pm 0.011(\rm stat.)\pm 0.020(\rm syst.))}\mathbf{\times 10^{-3}}×10−3 is found to be in agreement with earlier measurements.

Measurements of branching fraction and direct CP asymmetry in B±→KS0KS0K± and a search for B±→KS0KS0π±

We study charmless hadronic decays of charged $B$ mesons to the final states $K^{0}_{S}K^{0}_{S}K^{\pm}$ and $K^{0}_{S}K^{0}_{S}\pi^{\pm}$ using a $711 fb^{-1}$ data sample that contains $772\times 10^6$ $B\bar{B}$ pairs, and was collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. For $B^{\pm}\to K^{0}_{S}K^{0}_{S}K^{\pm}$, the measured branching fraction and direct $CP$ asymmetry are $[10.42\pm0.43(stat)\pm 0.22(syst)]\times10^{-6}$ and [$+1.6\pm3.9(stat)\pm 0.9(syst)$]%, respectively. In the absence of a statistically significant signal for $B^{\pm}\to K^{0}_{S}K^{0}_{S}\pi^{\pm}$, we obtain a 90% confidence-level upper limit on its branching fraction as $8.7 \times10^{-7}$.

Measurements of the absolute branching fractions and CP asymmetries for D+→KS,L0K+(π0)

Using $e^+e^-$ collision data corresponding to an integrated luminosity of 2.93 fb$^{-1}$ taken at a center-of-mass energy of 3.773 GeV with the BESIII detector, we determine the absolute branching fractions $\mathcal{B}(D^+\rightarrow K_S^0 K^+)$ = $(3.02 \pm 0.09 \pm 0.08)\times10^{-3}$, $\mathcal{B}(D^+\rightarrow K_S^0 K^+ \pi^0)$ = $(5.07 \pm 0.19 \pm 0.23)\times10^{-3}$, $\mathcal{B}(D^+\rightarrow K_L^0 K^+)$ = $(3.21 \pm 0.11 \pm 0.11)\times10^{-3}$, and $\mathcal{B}(D^+\rightarrow K_L^0 K^+ \pi^0)$ = $(5.24 \pm 0.22 \pm 0.22)\times10^{-3}$, where the first and second uncertainties are statistical and systematic, respectively. The branching fraction \wbrksk is consistent with the world average value and the other three branching fractions are measured for the first time. We also measure the $CP$ asymmetries for the four decays and do not find a significant deviation from zero.

XYZ at Belle

Recent results of exotic states with heavy quarks, denoted as XYZ states, are presented. The results include searches for the Y(4260) in B meson decays, a spin partner of Y(4630), and the strange Pentaquark $ P_s^ + $. An addition, the measurements of the absolute branching fraction of X(3872) and search for double Zc production is dicussed.

New results on charmonium like states at Belle

New results on charmonium-like states measured by the Belle experiment at the KEKB asymmetric e+e- collider are presented, in particular (a) Search for the Zc pair production in $\Upsilon (1{\rm{S}}),\,\Upsilon (2S)$ decays and in e+e- $\sqrt s $ of 10.52, 10.58, and 10.867 GeV. (b) Measurement of the absolute branching fractions of ${B^ + } \to {X_{c\overline c }}{K^ + }$ decays. (c) Observation of Ξc(2930)0 in the updated measurement of ${B^ - } \to {K^ - }{\Lambda _c}{\overline \Lambda _{\overline c }}.$ (d) Angular analysis of ${e^ + }{e^ - } \to {D^{(*) \pm }}{D^{* \mp }}$ process near the open charm threshold using initial state radiation.

Observation of the decay Bs0→D¯0K+K−

The first observation of the $B_s^0 \to \overline{D}^0 K^+ K^-$ decay is reported, together with the most precise branching fraction measurement of the mode $B^0 \to \overline{D}^0 K^+ K^-$. The results are obtained from an analysis of $pp$ collision data corresponding to an integrated luminosity of $3.0~\textrm{fb}^{-1}$. The data were collected with the LHCb detector at centre-of-mass energies of $7$ and $8$ TeV. The branching fraction of the $B^0 \to \overline{D}^0 K^+ K^-$ decay is measured relative to that of the decay $B^0 \to \overline{D}^0 \pi^+ \pi^-$ to be $$\frac{\mathcal{B}(B^0 \to \overline{D}^0 K^+ K^-)}{\mathcal{B}(B^0 \to \overline{D}^0 \pi^+ \pi^-)} = (6.9 \pm 0.4 \pm 0.3)\%,$$ where the first uncertainty is statistical and the second is systematic. The measured branching fraction of the $B_s^0 \to \overline{D}^0 K^+ K^-$ decay mode relative to that of the corresponding $B^0$ decay is $$\frac{\mathcal{B}(B_s^0 \to \overline{D}^0 K^+ K^-)}{\mathcal{B}(B^0 \to \overline{D}^0 K^+ K^-)} = (93.0 \pm 8.9 \pm 6.9)\%.$$ Using the known branching fraction of ${B^0 \to \overline{D}^0 \pi^+ \pi^-}$, the values of ${{\mathcal B}(B^0 \to \overline{D}^0 K^+ K^- )=(6.1 \pm 0.4 \pm 0.3 \pm 0.3) \times 10^{-5}}$, and ${{\cal B}(B_s^0 \to \overline{D}^0 K^+ K^-)=}$ $(5.7 \pm 0.5 \pm 0.4 \pm 0.5) \times 10^{-5}$ are obtained, where the third uncertainties arise from the branching fraction of the decay modes ${B^0 \to \overline{D}^0 \pi^+ \pi^-}$ and $B^0 \to \overline{D}^0 K^+ K^-$, respectively.

Measurement of the spectral function for the τ−→K−KSντ decay

The decay $\tau^{-}\to K^{-}K_S\nu_{\tau}$ has been studied using $430\times10^6$ $e^+e^-\to \tau^+\tau^-$ events produced at a center-of-mass energy around 10.6 GeV at the PEP-II collider and studied with the BABAR detector. The mass spectrum of the $K^{-}K_S$ system has been measured and the spectral function has been obtained. The measured branching fraction ${\cal B}(\tau^{-}\to K^{-}K_S\nu_{\tau}) = (0.739\pm 0.011(\rm stat.)\pm 0.020(\rm syst.))\times 10^{-3}$ is found to be in agreement with earlier measurements.

Observation of ψ(3686)→nn¯ and improved measurement of ψ(3686)→pp¯

We observe the decay $\psi(3686) \to n \bar{n}$ for the first time and measure $\psi(3686) \to p \bar{p}$ with improved accuracy by using $1.07\times 10^8$ $\psi(3686)$ events collected with the BESIII detector. The measured branching fractions are $\mathcal{B}(\psi(3686) \to n \bar{n}) = (3.06 \pm 0.06 \pm 0.14)\times 10^{-4}$ and $\mathcal{B}(\psi(3686) \to p \bar{p}) = (3.05 \pm 0.02 \pm 0.12) \times 10^{-4}$. Here, the first uncertainties are statistical and the second ones systematic. With the hypothesis that the polar angular distributions of the neutron and proton in the center-of-mass system obey $1+\alpha \cos^2\theta$, we determine the $\alpha$ parameters to be $\alpha_{n\bar{n}} = 0.68 \pm 0.12 \pm 0.11$ and $\alpha_{p\bar{p}} = 1.03 \pm 0.06 \pm 0.03$ for $\psi(3686)\to n\bar{n}$ and $\psi(3686)\to p\bar{p}$, respectively.

On the model dependence of measured Bs-meson branching fractions

The measurement of Bs-meson branching fractions is a fundamental tool to probe physics beyond the Standard Model. Every measurement of untagged time-integrated Bs-meson branching fractions is model-dependent due to the time dependence of the experimental efficiency and the large lifetime difference between the two Bs mass eigenstates. In recent measurements, this effect is bundled in the systematics. We reappraise the potential numerical impact of this effect – we find it to be close to 10% in real-life examples where new physics is a correction to dominantly Standard-Model dynamics. We therefore suggest that this model dependence be made explicit, i.e. that Bs branching-fraction measurements be presented in a two-dimensional plane with the parameter that encodes the model dependence. We show that ignoring this effect can lead to over-constraining the couplings of new-physics models. In particular, we note that the effect also applies when setting upper limits on non-observed Bs decay modes, such as those forbidden within the Standard Model.

Evidence for the decay {B}_S^0to {overline{K}}^{ast 0}{mu}^{+}{mu}^{-}

A search for the decay {B}_S^0to {overline{K}}^{ast 0}{mu}^{+}{mu}^{-} is presented using data sets corresponding to 1.0, 2.0 and 1.6 fb−1 of integrated luminosity collected during pp collisions with the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, respectively. An excess is found over the background-only hypothesis with a significance of 3.4 standard deviations. The branching fraction of the {B}_S^0to {overline{K}}^{ast 0}{mu}^{+}{mu}^{-} decay is determined to be mathrm{mathcal{B}}left({B}_s^0to {overline{K}}^{ast 0}{mu}^{+}{mu}^{-}right)=left[2.9pm 1.0left(mathrm{stat}right)pm 0.2left(mathrm{syst}right)pm 0.3left(mathrm{norm}right)right]times {10}^{-8} , where the first and second uncertainties are statistical and systematic, respectively. The third uncertainty is due to limited knowledge of external parameters used to normalise the branching fraction measurement.

Measurements of absolute branching fractions for [formula omitted] and Ξ(1530)0K+

We report the first measurements of absolute branching fractions for the W-exchange-only processes Λc+→Ξ0K+ and Λc+→Ξ(1530)0K+ with the double-tag technique, by analyzing an e+e− collision data sample, that corresponds to an integrated luminosity of 567 pb−1 collected at a center-of-mass energy of 4.6 GeV by the BESIII detector. The branching fractions are measured to be B(Λc+→Ξ0K+)=(5.90±0.86±0.39)×10−3 and B(Λc+→Ξ(1530)0K+)=(5.02±0.99±0.31)×10−3, where the first uncertainties are statistical and the second systematic. Our results are more precise than the previous relative measurements.

Study of ϒ(1S) radiative decays to γπ+π− and γK+K−

We study the $\Upsilon(1S)$ radiative decays to $\gamma \pi^+ \pi^-$ and $\gamma K^+ K^-$ using data recorded with the BaBar detector operating at the SLAC PEP-II asymmetric-energy $e^+ e^-$ collider at center-of-mass energies at the $\Upsilon(2S)$ and $\Upsilon(3S)$ resonances. The $\Upsilon(1S)$ resonance is reconstructed from the decay $\Upsilon(nS)\to \pi^+ \pi^- \Upsilon(1S)$, $n=2,3$. Branching fraction measurements and spin-parity analyses of $\Upsilon(1S)$ radiative decays are reported for the I=0 $S$-wave and $f_2(1270)$ resonances in the $\pi^+ \pi^-$ mass spectrum, the $f_2'(1525)$ and $f_0(1500)$ in the $ K^+ K^-$ mass spectrum, and the $f_0(1710)$ in both.

Test of lepton flavor universality by the measurement of the B0→D*−τ+ντ branching fraction using three-prong τ decays

The ratio of branching fractions ${\cal{R}}(D^{*-})\equiv {\cal{B}}(B^0 \to D^{*-} \tau^+ \nu_{\tau})/{\cal{B}}(B^0 \to D^{*-} \mu^+\nu_{\mu})$ is measured using a data sample of proton-proton collisions collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3$~$fb$^{-1}$. The $\tau$ lepton is reconstructed with three charged pions in the final state. A novel method is used that exploits the different vertex topologies of signal and backgrounds to isolate samples of semitauonic decays of $b$ hadrons with high purity. Using the $B^0 \to D^{*-}\pi^+\pi^-\pi^+$ decay as the normalization channel, the ratio ${\cal{B}}(B^0 \to D^{*-} \tau^+ \nu_{\tau})/{\cal{B}}(B^0 \to D^{*-}\pi^+\pi^-\pi^+)$ is measured to be $1.97 \pm 0.13 \pm 0.18$, where the first uncertainty is statistical and the second systematic. An average of branching fraction measurements for the normalization channel is used to derive ${\cal{B}}(B^0 \to D^{*-} \tau^+ \nu_{\tau}) = (1.42 \pm 0.094 \pm 0.129 \pm 0.054) \%$, where the third uncertainty is due to the limited knowledge of ${\cal{B}}(B^0\to D^{*-}\pi^+\pi^-\pi^+)$. A test of lepton flavor universality is performed using the well-measured branching fraction ${\cal{B}}(B^0 \to D^{*-} \mu^+\nu_{\mu})$ to compute ${\cal{R}}(D^{*-}) = 0.291 \pm 0.019 \pm 0.026 \pm 0.013$, where the third uncertainty originates from the uncertainties on ${\cal{B}}(B^0 \to D^{*-}\pi^+\pi^-\pi^+)$ and ${\cal{B}}(B^0 \to D^{*-} \mu^+\nu_{\mu})$. This measurement is in agreement with the Standard Model prediction and with previous measurements.