arXiv subjects

S. Eidelman

Publications and source records attributed to S. Eidelman.

At least 199 records · Page 11Linked to original sources

arXiv2015

Analysis Tools for Next-Generation Hadron Spectroscopy Experiments

The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopy in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near Berlin in September 2013. The aim of this document is to summarize the discussions that took place at the ATHOS 2012 and ATHOS 2013 meetings. We do not attempt a comprehensive review of the field of amplitude analysis, but offer a collection of thoughts that we hope may lay the ground for such a document.

hep-ph↗

arXiv2015

Search for $B^+ \to e^+ ν$ and $B^+ \to μ^+ ν$ decays using hadronic tagging

We present a search for the rare leptonic decays $B^+ \to e^+ ν_e$ and $B^+ \to μ^+ ν_μ$, using the full $Υ(4S)$ data sample of $772\times 10^6$ $B\bar{B}$ pairs collected with the Belle detector at the $\small\textbf{KEKB}$ asymmetric-energy $e^+ e^-$ collider. One of the $B$ mesons from the $Υ(4S) \to B\bar{B}$ decay is fully reconstructed in a hadronic mode, while the recoiling side is analyzed for the signal decay. We find no evidence of a signal in any of the decay modes. Upper limits of the corresponding branching fractions are determined as ${\cal B}(B^+ \to e^+ ν_e)<3.5\times 10^{-6}$ and ${\cal B}(B^+ \to μ^+ ν_μ)<2.7 \times 10^{-6}$ at 90$\%$ confidence level.

hep-ex↗

arXiv2015

Measurement of the amplitude ratio of $B^0 \to D^0K^{0}$ and $B^0 \to \bar{D^0}K^{0}$ decays with a model-independent Dalitz plot analysis using $D\to K_S^0π^+π^-$ decays

We report a measurement of the amplitude ratio $r_S$ of $B^0 \to D^0K^{*0}$ and $B^0 \to \bar{D^0}K^{*0}$ decays with a model-independent Dalitz plot analysis using $D\to K_S^0π^+π^-$ decays. Using the full data sample of $772\times10^6$ $B\bar{B}$ pairs collected at the $Υ(4S)$ resonance with the Belle detector at KEKB accelerator the upper limit is $r_S < 0.87$ at the 68 % confidence level. This result is the first measurement of $r_S$ with a model-independent Dalitz analysis, and is consistent with results from other analyses. The value of $r_S$ indicates the sensitivity of the decay to $ϕ_3$ because the statistical uncertainty is proportional to $1/r_S$. The $r_S$ result is obtained from observables ($x_\pm$, $y_\pm$) \begin{eqnarray} x_- &=& +0.4 ^{+1.0 +0.0}_{-0.6 -0.1} \pm0.0 \\ y_- &=& -0.6 ^{+0.8 +0.1}_{-1.0 -0.0} \pm0.1 \\ x_+ &=& +0.1 ^{+0.7 +0.0}_{-0.4 -0.1} \pm0.1 \\ y_+ &=& +0.3 ^{+0.5 +0.0}_{-0.8 -0.1} \pm0.1 \\ , \end{eqnarray} where $x_\pm = r_S \cos(δ_S \pm ϕ_3)$, $y_\pm = r_S \sin(δ_S \pm ϕ_3)$ and $ϕ_3 (δ_S)$ are the weak (strong) phase difference between $B^0 \to D^0K^{*0}$ and $B^0 \to \bar{D^0}K^{*0}$. The first uncertainty is statistical, the second is the experimental systematic and the third is the systematic due to the uncertainties on $c_i$ and $s_i$ parameters measured by CLEO.

hep-ex↗

arXiv2015

Search for the decay $B^+\rightarrow\overline{K}{}^{0}K^{+}$ at Belle

We report a search for the rare charmless decay $B^+\rightarrow\overline{K}{}^{*0}K^{*+}$ using a data sample of $772\times10^6$ $B\bar{B}$ pairs collected at the $Υ(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. No statistically significant signal is found and a 90% confidence-level upper limit is set on the decay branching fraction as $ \mathcal{B}(B^+\rightarrow\overline{K}{}^{*0}K^{*+}) <1.31\times 10^{-6}$.

hep-ex↗

arXiv2014

MesonNet 2014 International Workshop. Mini-proceedings

The MesonNet International Workshop was held in the Laboratori Nazionali di Frascati from September the 29th to October the 1st, 2014, being the concluding meeting of the MesonNet research network within EU HadronPhysics3 project. MesonNet is a research network focused on light meson physics gathering experimentalist and theoreticians from Europe and abroad. An overview of the research projects related to the scope of the network is presented in these mini-proceedings.

nucl-ex↗

arXiv2014

Observation of a new charged charmoniumlike state in B -> J/psi K pi decays

We present the results of an amplitude analysis of anti-B0 -> J/psi K- pi+ decays. A new charged charmoniumlike state Zc(4200)+ decaying to J/psi pi+ is observed with a significance of 6.2 sigma. The mass and width of the Zc(4200)+ are 4196 +31-29 +17-13 MeV/c^2 and 370 +70-70 +70-132 MeV, respectively; the preferred assignment of the quantum numbers is J^P = 1^+. In addition, we find evidence for Zc(4430)+ -> J/psi pi+. The analysis is based on a 711 fb^-1 data sample collected by the Belle detector at the asymmetric-energy e+ e- collider KEKB.

hep-ex↗

arXiv2014

Search for $B_{s}^{0}\rightarrowγγ$ and a measurement of the branching fraction for $B_{s}^{0}\rightarrowϕγ$

We search for the decay $B_{s}^{0}\rightarrowγγ$ and measure the branching fraction for $B_{s}^{0}\rightarrowϕγ$ using 121.4~$\textrm{fb}^{-1}$ of data collected at the $Υ(\mathrm{5}S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. The $B_{s}^{0}\rightarrowϕγ$ branching fraction is measured to be $(3.6 \pm 0.5 (\mathrm{stat.}) \pm 0.3 (\mathrm{syst.}) \pm 0.6 (f_{s})) \times 10^{-5}$, where $f_{s}$ is the fraction of $B_{s}^{(*)}\bar{B}_{s}^{(*)}$ in $b\bar{b}$ events. Our result is in good agreement with the theoretical predictions as well as with a recent measurement from LHCb. We observe no statistically significant signal for the decay $B_{s}^{0}\rightarrowγγ$ and set a $90\%$ confidence-level upper limit on its branching fraction at $ 3.1 \times 10^{-6}$. This constitutes a significant improvement over the previous result.

hep-ex↗

arXiv2014

Measurement of the $\bar{B} \rightarrow X_s γ$ Branching Fraction with a Sum of Exclusive Decays

We use 772$\times 10^6$ $B \bar{B}$ meson pairs collected at the $Υ(4S)$ resonance with the Belle detector to measure the branching fraction for $\bar{B} \rightarrow X_s γ$. Our measurement uses a sum-of-exclusives approach in which 38 of the hadronic final states with strangeness equal to $+1$, denoted by $X_s$, are reconstructed. The inclusive branching fraction for $M_{X_s}<$ 2.8 GeV/$c^2$, which corresponds to a minimum photon energy of 1.9 GeV, is measured to be ${\cal B}(\bar{B} \rightarrow X_s γ)=(3.51\pm0.17\pm0.33)\times10^{-4}$, where the first uncertainty is statistical and the second is systematic.

hep-ex↗

arXiv2014

Evidence of $Υ(1S) \to J/ψ+χ_{c1}$ and search for double-charmonium production in $Υ(1S)$ and $Υ(2S)$ decays

Using data samples of $102\times10^6$ $Υ(1S)$ and $158\times10^6$ $Υ(2S)$ events collected with the Belle detector, a first experimental search has been made for double-charmonium production in the exclusive decays $Υ(1S,2S)\rightarrow J/ψ(ψ')+X$, where $X=η_c$, $χ_{cJ} (J=~0,~1,~2)$, $η_c(2S)$, $X(3940)$, and $X(4160)$. No significant signal is observed in the spectra of the mass recoiling against the reconstructed $J/ψ$ or $ψ'$ except for the evidence of $χ_{c1}$ production with a significance of $4.6σ$ for $Υ(1S)\rightarrow J/ψ+χ_{c1}$. The measured branching fraction $\BR(Υ(1S)\rightarrow J/ψ+χ_{c1})$ is $(3.90\pm1.21(\rm stat.)\pm0.23 (\rm syst.))\times10^{-6}$. The $90\%$ confidence level upper limits on the branching fractions of the other modes having a significance of less than $3σ$ are determined. These results are consistent with theoretical calculations using the nonrelativistic QCD factorization approach.

hep-ex↗

arXiv2014

Measurement of Time-Dependent $CP$ Violation in $B^0\to η'K^0$ Decays

We present a measurement of the time-dependent $CP$ violation parameters in $B^0\toη'K^0$ decays. The measurement is based on the full data sample containing $772\times 10^6$ $B\bar{B}$ pairs collected at the $Υ(4S)$ resonance using the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. The measured values of the mixing-induced and direct $CP$ violation parameters are: \begin{align} \sin 2 ϕ^{\rm eff}_1 &= +0.68\pm 0.07 \pm 0.03, \nonumber \\ \mathcal{A}_{η'K^0} &= +0.03\pm 0.05\pm 0.04, \nonumber \end{align} where the first uncertainty is statistical and the second is systematic. The values obtained are the most accurate to date. Furthermore, these results are consistent with our previous measurements and with the world-average value of $\sin 2ϕ_1$ measured in $B^0\to J/ψK^0$ decays.}

hep-ex↗

arXiv2014

Measurement of $B^0 \to D_s^- K^0_Sπ^+$ and $B^+ \to D_s^- K^+K^+$ branching fractions

We report a measurement of the $B^0$ and $B^+$ meson decays to the $D_s^-K^0_S π^+$ and $D_s^- K^+K^+$ final states, respectively, using $657 \times 10^{6} B\overline{B}$ pairs collected at the $Υ(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. Using the $D_s^-\to ϕπ^-$, $K^{*}(892)^0 K^-$ and $K^0_S K^-$ decay modes for the $D_s$ reconstruction, we measure the following branching fractions: ${\cal B}(B^0\to D_s^{-}K^0_Sπ^+)=[0.47 \pm 0.06 (\mathrm {stat}) \pm 0.05 (\mathrm {syst})]\times 10^{-4}$ and ${\cal B}(B^+\to D_s^-K^+K^+)= [0.93 \pm 0.22 (\mathrm {stat})\pm 0.10 (\mathrm {syst})]\times 10^{-5}$. We find the ratio of the branching fraction of $B^+\to D_s^-K^+K^+$ to that of the analogous Cabibbo favored $B^+\to D_s^-K^+π^+$ decay to be ${\cal R}_{\cal B} = 0.054 \pm 0.013 ({\rm stat}) \pm 0.006 ({\rm syst})$, which is consistent with the na\"ıve factorization model. We also observe a deviation from the three-body phase-space model for both studied decays.

hep-ex↗

arXiv2014

Measurement of the inclusive semileptonic branching fraction $\mathcal{B}(B_s^0 \rightarrow X^- \ell^+ ν_\ell)$ at Belle

We report a measurement of the inclusive semileptonic $B_s^0$ branching fraction in a $121~fb^{-1}$ data sample collected near the $Υ(5S)$ resonance with the Belle detector at the KEKB asymmetric energy $e^+ e^-$ collider. Events containing $B_s^0$ pairs are selected by reconstructing a tag side $D_s^+$ and identifying a signal side lepton $\ell^+$ ($\ell = e, μ$) that is required to have the same-sign charge to ensure that both originate from different $B_s^0$ mesons. The $B_s^0 \rightarrow X^- \ell^+ ν_\ell$ branching fraction is extracted from the ratio of the measured yields of $D_s^+$ mesons and $D_s^+ \ell^+$ pairs and the known production and branching fractions. The inclusive semileptonic branching fraction is measured to be $[9.6 \pm 0.4\text{(stat)} \pm 0.7\text{(syst)}]~\%$.

hep-ex↗

arXiv2014

Measurement of the branching fraction of $B^+ \to τ^+ ν_τ$ decays with the semileptonic tagging method and the full Belle data sample

We report a measurement of the branching fraction of $B^+ \to τ^+ ν_τ$ decays using a data sample of $772 \times 10^6 B \bar{B}$ pairs, collected at the $Υ(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We reconstruct the accompanying $B$ meson in a semileptonic decay and detect the $B^+ \to τ^+ ν_τ$ candidate in the recoiling event. We obtain a branching fraction of ${\cal B}(B^+ \to τ^+ ν_τ) = [1.25 \pm 0.28 ({\rm stat.}) \pm 0.27({\rm syst.})] \times 10^{-4}$. This result is in good agreement with previous measurements and the expectation from calculations based on the Standard Model.

hep-ex↗

arXiv2014

Observation of $e^+e^- \to π^+ π^- π^0 χ_{bJ}$ and search for $X_b \to ωΥ(1S)$ at $\sqrt{s}\sim 10.867$ GeV

The $e^+e^- \to π^+ π^- π^0 χ_{bJ}$ ($J=0,~1,~2$) processes are studied using a 118~fb$^{-1}$ data sample collected at a center-of-mass energy of 10.867 GeV, in the $Υ(10860)$ energy range, with the Belle detector. The $π^+ π^- π^0 χ_{b1}$, $π^+π^-π^0χ_{b2}$, $ωχ_{b1}$ signals and the evidence of $ωχ_{b2}$ are observed for the first time and the cross sections are measured. No significant $π^+π^-π^0χ_{b0}$ or $ωχ_{b0}$ signal is observed and 90\% confidence level upper limits on the cross sections for these two processes are obtained. In the $π^+π^-π^0$ invariant mass spectrum, significant non-$ω$ signals are also observed. We search for the $X(3872)$-like state with a hidden $b\bar{b}$ component (named $X_b$) decaying into $ωΥ(1S)$; no significant signal is observed with a mass between $10.55$ and $10.65$ GeV/$c^2$.

hep-ex↗

arXiv2014

Observation of the decay $B^0 \to η' K^*(892)^0$

We report a search for charmless hadronic decays of neutral $B$ mesons to $η' K^{*}(892)^{0}$. The results are based on a 711fb$^{-1}$ data sample that contains $772\times 10^6 B\overline{B}$ pairs, collected at the $Υ(4S)$ resonance with the Belle detector at the KEKB asymmetric energy $e^+e^-$ collider. We observe the decay for the first time with a significance of 5.0 standard deviations and obtain its branching fraction ${\cal B}[B^0\toη' K^{*}(892)^{0}]=[2.6\pm0.7{\rm (stat)}\pm0.2{\rm (syst)}]\times 10^{-6}$. We also measure the $CP$ violating asymmetry as ${\cal A}_{CP}[B^0\toη' K^{*}(892)^{0}]=-0.22\pm0.29{\rm (stat)}\pm0.07{\rm syst}$.

hep-ex↗

arXiv2014

Measurement of the Branching Fraction Br(Lambda_c+ -> p K- pi+)

We present the first model-independent measurement of the absolute branching fraction of the Lambda_c+ -> p K- pi+ decay using a data sample of 978 fb^-1 collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. The number of Lambda_c+ baryons is determined by reconstructing the recoiling D(*)- anti-p pi+ system in events of the type e+e- -> D(*)- anti-p pi+ Lambda_c+. The branching fraction is measured to be Br(Lambda_c+ -> p K- pi+) = (6.84 +- 0.24^{+0.21}_{-0.27})%, where the first and second uncertainties are statistical and systematic, respectively.

hep-ex↗

arXiv2014

Search for CP violation in D^0 -> pi^0 pi^0 decays

We search for CP violation in neutral charm meson decays using a data sample with an integrated luminosity of 966 fb^-1 collected with the Belle detector at the KEKB e+e- asymmetric-energy collider. The asymmetry obtained in the rate of D^0 and D^0-bar decays to the pi^0 pi^0 final state, [-0.03+-0.64(stat)+-0.10(syst)]%, is consistent with no CP violation. This constitutes an order of magnitude improvement over the existing result. We also present an updated measurement of the CP asymmetry in the D^0 -> K_S pi^0 decay: A_{CP}(D^0 -> K_S pi^0) = [-0.21+-0.16(stat)+-0.07(syst)]%.

hep-ex↗

arXiv2014

Measurement of Branching Fractions and CP Asymmetries in B -> wK Decays and First Evidence of CP Violation in B0 -> wKS0

We present a measurement of the branching fractions and charge-parity-(CP-) violating parameters in B -> omega K decays. The results are obtained from the final data sample containing 772 x 10^(6) BBbar pairs collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We obtain the branching fractions B(B0 -> omega K0) = (4.5 +/- 0.4 (stat) +/- 0.3 (syst)) x 10^(-6), B(B- -> omega K-) = (6.8 +/- 0.4 (stat) +/- 0.4 (syst)) x 10^(-6), which are in agreement with their respective current world averages. For the CP violating parameters, we obtain A(B0 -> omega KS) = -0.36 +/- 0.19 (stat) +/- 0.05 (syst), S(B0 -> omega KS) = +0.91 +/- 0.32 (stat) +/- 0.05 (syst), A(B- -> omega K-) = -0.03 +/- 0.04 (stat) +/- 0.01 syst), where A and S represent the direct and mixing-induced CP asymmetry, respectively. We find no evidence of CP violation in the decay channel B-->omega K-; however, we obtain the first evidence of CP violation in the B0 -> omega KS decay channel at the level of 3.1 standard deviations.

hep-ex↗