Observation of excited Ω c charmed baryons in e + e − collisions

Using the entire Belle data sample of 980  fb−1 of e+e− collisions, we present the results of a study of excited Ωc charmed baryons in the decay mode Ξ+cK−. We show confirmation of four of the five narrow states reported by the LHCb Collaboration: the Ωc(3000), Ωc(3050), Ωc(3066), and Ωc(3090)

Study of K 0 S pair production in single-tag two-photon collisions

We report a measurement of the cross section for K0S pair production in single-tag two-photon collisions, γ∗γ→K0SK0S, for Q2 up to 30  GeV2, where Q2 is the negative of the invariant mass squared of the tagged photon. The measurement covers the kinematic range 1.0  Ge

Observation of Υ(4S)→η′Υ(1S)

We report the first observation of the hadronic transition Υ(4S)→η′Υ(1S), using 496 fb−1 data collected at the Υ(4S)resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. We reconstruct the η′ meson through its decays to ρ0γ and to π+π−η, with η→γγ. We measure: (Υ(4S)→η′Υ(1S))=(3.43±0.88(stat.)±0.21(syst.))×10−5, with a significance of 5.7σ

Measurement of time-dependent C P asymmetries in B 0 → K 0 S η γ decays

We report a measurement of time-dependent CP violation parameters in B0→K0Sηγ decays. The study is based on a data sample, containing 772×106B¯B pairs, that was collected at the Υ(4S)resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. We obtain the CPviolation parameters of S=−1.32±0.77(stat)±0.36(syst) and A=−0.48±0.41(stat)±0.07(syst) for the invariant mass of the K0Sη system up to 2.1 GeV/c2

Measurement of the τ lepton polarization and R ( D ∗ ) in the decay ¯ B → D ∗ τ − ¯ ν τ with one-prong hadronic τ decays at Belle

With the full data sample of 772×106 B¯B pairs recorded by the Belle detector at the KEKB electron-positron collider, the decay ¯B→D∗τ−¯ντ is studied with the hadronic τ decays τ−→π−ντ and τ−→ρ−ντ. The τ polarization Pτ(D∗) in two-body hadronic τ decays is measured, as well as the ratio of the branching fractions R(D∗)=B(¯B→D∗τ−¯ντ)/B(¯B→D∗ℓ−¯νℓ), where ℓ− denotes an electron or a muon. Our results, Pτ(D∗)=−0.38±0.51(stat)+0.21−0.16(syst) and R(D∗)=0.270±0.035(stat)+0.028−0.025(syst), are consistent with the theoretical predictions of the standard model. The polarization values of Pτ(D∗)\u3e+0.5 are excluded at the 90% confidence level

Observation of Ξc(2930)0 and updated measurement of B−→K−Λ+cΛ¯−c at Belle

We report the first observation of the Ξc(2930)0 role= presentation style= box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; \u3eΞc(2930)0Ξc(2930)0 charmed-strange baryon with a significance greater than 5σ role= presentation style= box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; \u3eσσ. The Ξc(2930)0 role= presentation style= box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; \u3eΞc(2930)0Ξc(2930)0 is found in its decay to K−Λc+ role= presentation style= box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; \u3eK−Λ+cK−Λc+ in B−→K−Λc+Λ¯c− role= presentation style= box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; \u3eB−→K−Λ+cΛ¯−cB−→K−Λc+Λ¯c− decays. The measured mass and width are [2928.9±3.0(stat.)−12.0+0.9(syst.)] role= presentation style= box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; \u3e[2928.9±3.0(stat.)+0.9−12.0(syst.)][2928.9±3.0(stat.)−12.0+0.9(syst.)] MeV/c2 role= presentation style= box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; \u3ec2c2 and [19.5±8.4(stat.)−7.9+5.9(syst.)] role= presentation style= box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; \u3e[19.5±8.4(stat.)+5.9−7.9(syst.)][19.5±8.4(stat.)−7.9+5.9(syst.)] MeV, respectively, and the product branching fraction is B(B−→Ξc(2930)0Λ¯c−)B(Ξc(2930)0→K−Λc+)=[1.73±0.45(stat.)±0.21(syst.)]×10−4 role= presentation style= box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; \u3e(B−→Ξc(2930)0Λ¯−c)(Ξc(2930)0→K−Λ+c)=[1.73±0.45(stat.)±0.21(syst.)]×10−4B(B−→Ξc(2930)0Λ¯c−)B(Ξc(2930)0→K−Λc+)=[1.73±0.45(stat.)±0.21(syst.)]×10−4. We also measure B(B−→K−Λc+Λ¯c−)=[4.80±0.43(stat.)±0.60(syst.)]×10−4 role= presentation style= box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; \u3e(B−→K−Λ+cΛ¯−c)=[4.80±0.43(stat.)±0.60(syst.)]×10−4B(B−→K−Λc+Λ¯c−)=[4.80±0.43(stat.)±0.60(syst.)]×10−4 with improved precision, and search for the charmonium-like state Y(4660) and its spin partner, Yη role= presentation style= box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; \u3eYηYη, in the Λc+Λ¯c− role= presentation style= box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; \u3eΛ+cΛ¯−cΛc+Λ¯c− invariant mass spectrum. No clear signals of the Y(4660) nor its spin partner are observed and the 90% credibility level (C.L.) upper limits on their production rates are determined. These measurements are obtained from a sample of (772±11)×106BB¯ role= presentation style= box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; \u3e(772±11)×106BB¯(772±11)×106BB¯ pairs collected at the Υ(4S) role= presentation style= box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; \u3eΥ(4S)Υ(4S) resonance by the Belle detector at the KEKB asymmetric energy electron–positron collider

Measurement of cos2β in B0→D(∗)h0 with D→K0Sπ+π− decays by a combined time-dependent Dalitz plot analysis of BaBar and Belle data

We report measurements of sin2β and cos2β from a time-dependent Dalitz plot analysis of B0→D(∗)h0 with D→K0Sπ+π−decays, where the light unflavored and neutral hadron h0 is a π0, η, or ω meson. The analysis is performed with a combination of the final data sets of the \babar\ and Belle experiments containing 471×106 and 772×106 BB¯ pairs collected at the Υ(4S)resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. We measure sin2β=0.80±0.14(stat.)±0.06(syst.)±0.03(model) and cos2β=0.91±0.22(stat.)±0.09(syst.)±0.07(model). The result for the direct measurement of the angle is β=(22.5±4.4(stat.)±1.2(syst.)±0.6(model))∘. The last quoted uncertainties are due to the composition of the D0→K0Sπ+π− decay amplitude model, which is newly established by a Dalitz plot amplitude analysis of a high-statistics e+e−→cc¯ data sample as part of this analysis. We find the first evidence for cos2β\u3e0 at the level of 3.7 standard deviations. The measurement excludes the trigonometric multifold solution π/2−β=(68.1±0.7)∘ at the level of 7.3 standard deviations and therefore resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle. The hypothesis of β=0∘ is ruled out at the level of 5.1 standard deviations, and thus CP violation is observed in B0→D(∗)h0 decays

First evidence for cos2β\u3e0 and resolution of the CKM Unitarity Triangle ambiguity by a time-dependent Dalitz plot analysis of B0→D(∗)h0 with D→K0Sπ+π− decays

We present first evidence that the cosine of the CP-violating weak phase 2β is positive, and hence exclude trigonometric multifold solutions of the CKM Unitarity Triangle using a time-dependent Dalitz plot analysis of B0→D(∗)h0 with D→K0Sπ+π− decays, where h0∈{π0,η,ω} denotes a light unflavored and neutral hadron. The measurement is performed combining the final data sets of the BaBar and Belle experiments collected at the Υ(4S) resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain (471±3)×106BB¯ pairs recorded by the BaBar detector and (772±11)×106BB¯ pairs recorded by the Belle detector. The results of the measurement are sin2β=0.80±0.14(stat.)±0.06(syst.)±0.03(model) and cos2β=0.91±0.22(stat.)±0.09(syst.)±0.07(model). The result for the direct measurement of the angle β of the CKM Unitarity Triangle is β=(22.5±4.4(stat.)±1.2(syst.)±0.6(model))∘. The quoted model uncertainties are due to the composition of the D0→K0Sπ+π− decay amplitude model, which is newly established by performing a Dalitz plot amplitude analysis using a high-statistics e+e−→cc¯ data sample. CP violation is observed in B0→D(∗)h0 decays at the level of 5.1 standard deviations. The significance for cos2β\u3e0 is 3.7 standard deviations. The trigonometric multifold solution π/2−β=(68.1±0.7)∘ is excluded at the level of 7.3 standard deviations. The measurement resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle

Measurement of the Decays Λc→Σππ at Belle

We report measurements of the branching fractions of the decays Λ+c→Σ+π−π+, Λ+c→Σ0π+π0 and Λ+c→Σ+π0π0 relative to the reference channel Λ+c→pK−π+. The analysis is based on the full data sample collected at and close to Υ(4S)resonance by the Belle detector at the KEKB asymmetric-energy e+e− collider corresponding to the integrated luminosity of 711 fb−1. We measure (Λ+c→Σ+π−π+)/(Λ+c→pK−π+)=0.706 ±0.003 ±0.029, (Λ+c→Σ0π+π0)/(Λ+c→pK−π+)=0.491 ±0.005 ±0.028 and (Λ+c→Σ+π0π0)/(Λ+c→pK−π+)=0.198 ±0.006 ±0.016. The listed uncertainties are statistical and systematic, respectively

Search for Υ ( 1 S , 2 S ) → Z + c Z ( \u27 ) c − and e + e − → Z + c Z ( \u27 ) c − at √ s = 10.52 , 10.58, and 10.867 GeV

The first search for double charged charmoniumlike state production in Υ(1S) and Υ(2S) decays and in e+e− annihilation at √s=10.52, 10.58, and 10.867 GeV is conducted using data collected with the Belle detector at the KEKB asymmetric energy electron-positron collider. No significant signals are observed in any of the studied modes, and the 90% credibility level upper limits on their product branching fractions in Υ(1S) and Υ(2S) decays [B(Υ(1S,2S)→Z+cZ(\u27)−c)×B(Z+c→π++c¯c) (c¯c=J/ψ, χc1(1P), ψ(2S))] and the product of Born cross section and branching fraction for e+e−→Z+cZ(\u27)−c (σ(e+e−→Z+cZ(\u27)−c)×B(Z+c→π++c¯c)) at √s=10.52, 10.58, and 10.867 GeV are determined. Here, Zc refers to the Zc(3900) and Zc(4200) observed in the πJ/ψ final state, the Zc1(4050) and Zc2(4250) in the πχc1(1P) final state, and the Zc(4050) and Zc(4430) in the πψ(2S)final state