We report the results of a search for the bottomonium ground state eta_b(1S) in the photon energy spectrum with a sample of (109 +/- 1) million of Upsilon(3S) recorded at the Upsilon(3S) energy with the BABAR detector at the PEP-II B factory at SLAC. We observe a peak in the photon energy spectrum at E_gamma = 921.2 {+2.1} {-2.8} (stat) +/- 2.4(syst) MeV with a significance of 10 standard deviations. We interpret the observed peak as being due to monochromatic photons from the radiative transition Upsilon(3S) -> gamma eta_b(1S). This photon energy corresponds to an eta_b(1S) mass of $9388.9 {+3.1} {-2.3} (stat) +/- 2.7(syst) MeV/c2. The hyperfine Upsilon(1S)-eta_b(1S) mass splitting is 71.4 {+2.3} {-3.1} (stat) +/- 2.7(syst) MeV/c2. The branching fraction for this radiative Upsilon(3S) decay is estimated to be (4.8 +/- 0.5(stat) +/- 1.2 (syst)) x 10^(-4).
We study inclusive di-pion decays using a sample of 108 x 10^6 Upsilon(3S) events recorded with the BABAR detector. We search for the decay mode Upsilon(3S) --> pi+ pi- h_b(1P) and find no evidence for the bottomonium spin-singlet state h_b(1P) in the invariant mass distribution recoiling against the pi+ pi- system. Assuming the h_b(1P) mass to be 9.900 GeV/c^2, we measure the upper limit on the branching fraction B[Upsilon(3S) --> pi+ pi- h_b(1P)] < 1.2 x 10^{-4}, at 90% confidence level. We also investigate the chi_{bJ}(2P) --> pi+ pi- chi_{bJ}(1P), Upsilon(3S) --> pi+ pi- Upsilon(2S), and U…
The results of a search for the bottomonium counterpart, denoted as Xb, of the exotic charmonium state X(3872) is presented. The analysis is based on a sample of pp collisions at sqrt(s) = 8 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 20.7 inverse femtobarns. The search looks for the exclusive decay channel Xb to Upsilon(1S) pi+ pi- followed by Upsilon(1S) to mu+ mu-. No evidence for an Xb signal is observed. Upper limits are set at the 95% confidence level on the ratio of the inclusive production cross sections times the branching fractions to …
Heavy Quarkonium Physics continues to be a focus of the work done by the CLEO Collaboration. We present several results in the spectroscopy of both bottomonium and charmonium systems using CLEO's data sets taken at the Upsilon(3S), Upsilon(2S) and Psi(2S) resonances.
After nine years of operation the BABAR experiment at the B factory PEPII (Standford Linear Accelerator Center) stopped data taking in April 2008. The last three month of data taking were devoted to e+e- collisions at center of mass energies of the Upsilon(2S), Upsilon(3S) and to an energy scan above the Upsilon(4S). Besides the observation of the bottomonium ground state eta_b, the center of mass energy dependent e+e- -> b bbar cross section was measured in the energy range from 10.54 to 11.20 GeV. BELLE observed an enhancement in the production cross section for e+e- -> Upsilon(nS) pi+ pi- -…
The heavy quark spin symmetry implies that in addition to the recently observed Z(10610) and Z(10650) molecular resonances with $I^G=1^+$ there should exist two or four molecular bottomonium-like states with $I^G=1^-$. Properties of these G-odd states are considered, including their production in the radiative transitions from Upsilon(5S), by applying the same symmetry to the Upsilon(5S) resonance and the transition amplitudes. The considered radiative processes can provide a realistic option for observing the yet hypothetical states.
Results of the latest CLEO contribution to bottomonium spectroscopy is presented, the confirmation of the eta_b(1S0) ground state of bottomonium in the radiative decay Upsilon(3S) -> gamma eta_b. The bottomonium hyperfine splitting is determined to be Delta M_hf(1S) = 68.5+-6.6+-2.0 MeV and the branching fraction B(Upsilon(3S) -> gamma eta_b=(7.1+-1.8+-1.1)x10^-4. These results are in good agreement with those reported by BaBar.
We study the Upsilon(3S,2S)->eta Upsilon(1S) and Upsilon(3S,2S)->pi+pi- Upsilon(1S) transitions with 122 million Upsilon(3S) and 100 million Upsilon(2S) mesons collected by the BaBar detector at the PEP-II asymmetric energy e+e- collider. We measure B[Upsilon(2S)->eta Upsilon(1S)]=(2.39+/-0.31(stat.)+/-0.14(syst.))10^-4 and Gamma[Upsilon(2S)->eta Upsilon(1S)]/Gamma[Upsilon(2S)-> pi+pi- Upsilon(1S)]=(1.35+/-0.17(stat.)+/-0.08(syst.))10^-3. We find no evidence for Upsilon(3S)->eta Upsilon(1S) and obtain B[Upsilon(3S)->eta Upsilon(1S)]<1.0 10^-4 and Gamma[Upsilon(3S)->eta Upsilon(1S)]/Gamma[Upsil…
We present the first observation of the bottomonium ground state eta_b(1S) in the photon energy spectrum using a sample of 109+/-1 million of Upsilon(3S) events recorded at the Upsilon(3S) energy with the BaBar detector at the PEP-II B factory at SLAC. A peak at E_gamma = 921.2 {+2.1}{-2.8}(stat) +/- 2.4(syst) MeV observed with a significance of 10 standard deviations in the photon energy spectrum is interpretated as being due to the radiative transition Upsilon(3S) -> gamma eta_b(1S). This photon energy corresponds to an eta_b(1S) mass of 9388.9 {+3.1}{-2.3}(stat) +/- 2.7(syst) MeV/c2. The hy…
The data for 9.3 million Upsilon(2S) and 20.9 million Upsilon(1S) taken with the CLEO III detector has been used to study the radiative population of states identified by their decay into twenty six different exclusive hadronic final states. In the Upsilon(2S) decays an enhancement is observed at a ~5 sigma level at a mass of 9974.6+-2.3(stat)+-2.1(syst) MeV. It is attributed to eta_b(2S), and corresponds to the Upsilon(2S) hyperfine splitting of 48.7+-2.3(stat)+-2.1(syst) MeV. In the Upsilon(1S) decays, the identification of eta_b(1S) is confirmed at a ~3 sigma level with M(eta_b(1S)) in agre…
We report the first observation of the transition Upsilon(2S) > eta Upsilon(1S), with branching fraction B=(2.1+0.7-0.6(stat.)+-0.3(syst.)) x 10^{-4} and statistical significance 5.3 sigma. Data were acquired with the CLEO detector at the CESR e+ e- symmetric collider. This is the first process observed involving a b-quark spin flip. Upper limits at 90% confidence level for related processes, in units of 10^{-4}, are B[Upsilon(2S) -> pi0 Upsilon(1S)] < 1.8, B[Upsilon(3S) -> eta Upsilon(1S)] < 1.8, B[Upsilon(3S) -> pi0 Upsilon(1S)] < 0.7, and B[Upsilon(3S) -> pi0 Upsilon(2S)] < 5.1.
Spectroscopy results for Belle and BaBar are reported. A particular focus is put on new results of the X(3872) state with its radiative decays to $J$/$ψ$$γ$ and $ψ'$$γ$, its decay into $J$/$ψ$3$π$ and the search for production in radiative Upsilon decays. Another focus is $L$=2 mesons, in particlar a possible $D$-wave assignment to the X(3872) and the confirmation of an Upsilon $D$-wave state.
We report on a study of exclusive radiative decays of the Upsilon(1S) resonance into the final states gamma pi^0 pi^0, gamma eta eta and gamma pi^0 eta, using 1.13 inverse femto-barn of e^+ e^- annihilation data collected at sqrt(s)= 9.46 GeV with the CLEO III detector operating at the Cornell Electron Storage Ring. In the channel gamma pi^0 pi^0, we measure the branching ratio for the decay mode Upsilon(1S) to gamma f_2(1270) to be (10.5 \pm 1.6 (+ 1.9)(-1.8)) x 10^-5. We place upper limits on the product branching ratios for the isoscalar resonances f_0(1500) and f_0(1710) for the pi^0 pi^0 …
We report on a search for the radiative decay of Upsilon(1S) to the pseudoscalar mesons eta and etaprime in 21.2 +/- 0.2 times 10^6 Upsilon(1S) decays collected with the CLEO III detector at the Cornell Electron Storage Ring (CESR). The eta meson was reconstructed in the three modes eta to gamma-gamma, eta to pi+pi-pi0 and eta to 3pi0. The etaprime meson was reconstructed in the mode etaprime to pi+ pi- eta with eta decaying through any of the above three modes, and also etaprime to gamma rho, where rho decays to pi^+ pi^-. Five out of the seven sub-modes are found to be virtually background-f…
We have performed a search for the eta_b(1S) meson in the radiative decay of the Upsilon(2S) resonance using a sample of 91.6 million Upsilon(2S) events recorded with the BABAR detector at the PEP-II B factory at the SLAC National Accelerator Laboratory. We observe a peak in the photon energy spectrum at E_gamma = 609.3 {+4.6} {-4.5} (stat) +/- 1.9 (syst) MeV, corresponding to an eta_b(1S) mass of 9394.2 {+4.8} {-4.9} (stat) +/- 2.0 (syst) MeV/c^2. The branching fraction for the decay Upsilon(2S) --> gamma eta_b(1S) is determined to be [3.9 +/-1.1 (stat) {+1.1} {-0.9} (syst)] x 10^(-4). We fin…
Using CLEO data, we report on the confirmation of the eta_b(1S0) ground state of bottomonium in the radiative decay Upsilon(3S) -> gamma eta_b. We determine its mass to be M(eta_b) = 9391.8 +- 6.6 +- 2.1 MeV, which corresponds to the hyperfine splitting Delta M_hf(1S) = 68.5 +- 6.6 +- 2.0 MeV, and the branching fraction B(Upsilon(3S) -> gamma eta_b) = (7.1 +- 1.8 +- 1.1) x 10^-4. These results agree with those previously reported by BaBar.
We have searched for the bottomonium eta_b(1S) via the hindered magnetic dipole (M1) photon transition Upsilon(3S) -> gamma eta_b(1S). No evidence for such a transition is found in the data sample of 4.7 x 10^6 Upsilon(3S)'s collected with the CLEO-III detector. We set upper limits on the branching ratio from 9.30 to 9.43 GeV/c^2 of eta_b(1S) masses. These upper limits rule out many previously published phenomenological estimates of the rate for this transition.
We present an improved measurement of the eta' meson energy spectrum in Upsilon(1S) decays, using 1.2 fb^{-1}} of data taken at the Upsilon(1S) center-of-mass energy with the CLEO III detector. We compare our results with models of eta' gluonic form factor that have been suggested to explain the unexpectedly large B to eta' X_s rate. Models based on perturbative QCD fail to fit the data for large eta' energies, showing that Standard Model strong interaction dynamics is not likely to provide an explanation for the large rate of high energy eta' observed in B decays.
Using the CLEO II detector at CESR, we measure the eta' - gluon - gluon form-factor in Y(1S) decays. This form-factor especially at large eta' energies may provide an explanation of the large rate for B -> Xs eta'. Our data do not support a large anomalous coupling at higher q^2 and thus the large eta' rate remains a mystery, possibly requiring a non-Standard Model explanation.
We report the observation of two narrow structures at 10610MeV/c^2 and 10650MeV/c^2 in the pi^{\pm}Upsilon(nS) (n=1,2,3) and pi^{\pm}h_b(mP) (m=1,2) mass spectra that are produced in association with a single charged pion in Upsilon(5S) decays. The measured masses and widths of the two structures averaged over the five final states are M_1=10608.4\pm2.0MeV/c^2, Gamma_1=15.6\pm2.5MeV and M_2=10653.2\pm1.5MeV/c^2, Gamma_2=14.4\pm3.2MeV. Analysis favors quantum numbers of I^G(J^P)=1^+(1^+) for both states. The results are obtained with a 121.4fb^{-1} data sample collected with the Belle detector …
The Born cross section and dressed cross section of $e^+e^-$ to $b\bar{b}$ and the total hadronic cross section in $e^+e^-$ annihilation in the bottomonium energy region are calculated based on the Rb values measured by the BaBar and Belle experiments. The data are used to calculate the vacuum polarization factors in the bottomonium energy region, and to determine the resonant parameters of the vector bottomonium(-like) states, the Y(10750), Upsilon(5S), and Upsilon(6S).
We report preliminary measurements of the exclusive charmless semileptonic branching fractions of the B+ --> eta l+ nu and B+ --> eta' l+ nu decays. These measurements are based on 316 fb-1 of data collected at the Y(4S) resonance by the BABAR detector. In events in which the decay of one B meson to a hadronic final state is fully reconstructed, the semileptonic decay of the recoiling B meson is identified by the detection of a charged lepton and an eta or eta'. We measure the branching fraction BR(B+ --> eta l+ nu) = (0.84 +/- 0.27 +/- 0.21) x 10-4, where the first error is statistical and th…
Recent results from the CLEO experiment on decays and partial widths of various bottomonium and charmonium resonances are presented. New measurements of the di-electron partial widths for the 3 bound-state Upsilons and the J/psi are discussed. A determination of the total hadronic cross section for the psi(3770) is made, which solves a 20-year-old puzzle. The Y(4260) state is confirmed and its decay into 2 new modes is measured.
We report the first observation of the spin-singlet bottomonium states h_b(1P) and h_b(2P) produced in the reaction e+e- --> hb(nP)pi+pi- using a 121.4fb-1 data sample collected at energies near the Upsilon(5S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We determine M[h_b(1P)]=(9898.3+/-1.1+1.0-1.1) MeV/c^2 and M[h_b(2P)]=(10259.8+/-0.6+1.4-1.0) MeV/c^2,which correspond to P-wave hyperfine splittings Delta(M_HF) = (+1.6+/-1.5) MeV/c^2 and (+0.5+1.6-1.2) MeV/c^2, respectively. The h_b(1P) and h_b(2P) are observed with significances of 5.5sigma and 11.2sigma, …
We present a measurement of the polarization observed for bottomonium states produced in p-Cu collisions at sqrt(s)=38.8 GeV. The angular distribution of the decay dimuons of the Upsilon(1S) state show no polarization at small xF and pT but significant positive transverse production polarization for either pT > 1.8 GeV/c or for xF > 0.35. The Upsilon(2S+3S) unresolved states show a large transverse production polarization at all values of xF and pT measured. These observations are compared with an NRQCD calculation that predicts a transverse polarization in bottomonium production arising from …
We have studied the inclusive photon spectra in Upsilon(2S) and Υ(3S) decays using a large statistics data sample obtained with the CLEO III detector. We present the most precise measurements of electric dipole (E1) photon transition rates and photon energies for Upsilon(2S)->gamma chi_bJ(1P) and Upsilon(3S)->gamma chi_bJ(2P) J=0,1,2. We measure the rate for a rare E1 transition Upsilon(3S)->gamma chi_b0(1P) for the first time. We also set upper limits on the rates for the hindered magnetic dipole (M1) transitions to the eta_b(1S) and eta_b(2S) states.
We calculate the branching ratios of chi_{b0} --> tau+ tau- via an s-channel Higgs boson and estimate the sensitivity to this process from Upsilon --> gamma chi_{b0} --> gamma tau+ tau-. We show that future running at the Upsilon(3S) at a very high luminosity super B factory can put significant constraints on the Type-II two-Higgs-doublet model when the discovered 125 GeV Higgs boson is the heavier of the two CP-even scalars.
We report evidence for the ground state of bottomonium, eta_b(1S), in the radiative decay Upsilon(3S) --> gamma eta_b in e^+e^- annihilation data taken with the CLEO III detector. Using 6 million Upsilon(3S) decays, and assuming Gamma(eta_b) = 10 MeV/c^2, we obtain B(Upsilon(3S) --> gamma eta_b) = (7.1 +- 1.8 +- 1.1) X 10^{-4}, where the first error is statistical and the second is systematic. The statistical significance is about 4 sigma. The mass is determined to be M(eta_b) = 9391.8 +- 6.6 +- 2.0 MeV/c^2, which corresponds to the hyperfine splitting Delta M_{hf}(1S)_b = 68.5 +- 6.6 +- 2.0 M…
The CLEO Collaboration has observed the first hadronic transition among bottomonium (b bbar) states other than the dipion transitions among vector states, Upsilon(nS) -> pi pi Upsilon(mS). In our study of Upsilon(3S) decays, we find a significant signal for Upsilon(3S) -> gamma omega Upsilon(1S) that is consistent with radiative decays Upsilon(3S) -> gamma chi_{b 1,2}(2P), followed by chi_{b 1,2} -> omega Upsilon(1S). The branching ratios we obtain are Br(chi_{b1} -> omega Upsilon(1S) = 1.63 (+0.35 -0.31) (+0.16 -0.15) % and Br(chi_{b2} -> omega Upsilon(1S) = 1.10 (+0.32 -0.28) (+0.11 - 0.10)%…
We search for bottomonium states in Upsilon(2S)-> (bb-bar) gamma decays with an integrated luminosity of 24.7fb^-1 recorded at the Upsilon(2S) resonance with the Belle detector at KEK, containing (157.8+-3.6) X 10^6 Upsilon(2S) events. The (bb-bar) system is reconstructed in 26 exclusive hadronic final states composed of charged pions, kaons, protons, and K^0_S mesons. We find no evidence for the state recently observed around 9975 MeV (X_(bb-bar)) in an analysis based on a data sample of 9.3 X 10^6 Upsilon(2S) events collected with the CLEO III detector. We set a 90 % confidence-level upper l…
We report the first observation of the radiative transition h_b(1P)->eta_b(1S)gamma, where the h_b(1P) is produced in Upsilon(5S)->h_b(1P)pi+pi- dipion transitions. We measure the eta_b(1S) mass to be (9401.0+-1.9+1.4-2.4)MeV/c^2 with a width of (12.4+5.5-4.6+11.5-3.4)MeV and a decay branching fraction of BF[h_b(1P)->eta_b(1S)gamma]=(49.8+-6.8+10.9-5.2)%. The measured eta_b(1S) mass corresponds to a hyperfine splitting of (59.3+-1.9+2.4-1.4)MeV/c^2. This value deviates significantly from the current world average obtained from measurements of Upsilon(3S)->eta_b(1S)gamma and Upsilon(2S)->eta_b(…
We present measurements of the inclusive production cross sections of the Upsilon(1S) bottomonium state in ppbar collisions at sqrt(s) = 1.96 TeV. Using the Upsilon(1S) to mu+mu- decay mode for a data sample of 159 +- 10 pb^-1 collected by the D0 detector at the Fermilab Tevatron collider, we determine the differential cross sections as a function of the Upsilon(1S) transverse momentum for three ranges of the Upsilon(1S) rapidity: 0 < |y| < 0.6, 0.6 < |y| < 1.2, and 1.2 < |y| < 1.8.
Originally designed for CP violation studies in the B meson system, the B-Factories recently showed an exciting capability for improving our experimental knowledge in the field of hadron spectroscopy. Here I will present some of the most recent BABAR results concerning bottomonium spectroscopy. In particular, I will report the first observation of the ground state eta_b in Y(nS) gamma eta_b and the results of an energy scan in the range of 10.54 to 11.20 GeV, that produced a new measurement of the e+e- -> bb cross section in the region of the Y(4S) and candidate Y(5S) and Y(6S) resonances, wit…
We present an improved measurement of the $η'$ meson energy spectrum in $Υ(1S)$ decays, using 1.2 fb^{-1} of data taken at the $Υ(1S)$ center-of-mass energy with the CLEO III detector. We compare our results with models of the $η'$ gluonic form factor that have been suggested to explain the unexpectedly large $B\to η'X_s$ rate. Models based on perturbative QCD fail to fit the data for large $η'$ energies, and thus an explanation outside the realm of the Standard Model or an improved understanding of non-perturbative QCD effects may be needed to account for this large rate.
In this Letter we describe a search for lepton flavor violation (LFV) in the bottomonium system. We search for leptonic decays of Upsilon(nS)(n=1,2, and 3) into muon and tau using the data collected with the CLEO III detector. We identify the tau lepton using its leptonic decay into electron and utilize multidimensional likelihood fitting with PDF shapes measured from independent data samples. We report our estimates of 95% CL upper limits on LFV branching fractions of Upsilon mesons. We interpret our results in terms of the exclusion plot for the energy scale of a hypothetical new interaction…
We calculate the cross sections and final state distributions for the processes e^+ e^- --> Upsilon(1S) (pi^+ pi^-, K^+ K^-, eta pi^0) near the Upsilon(5S) resonance based on the tetraquark hypothesis. This framework is used to analyse the data on the Upsilon(1S) pi^+ pi^- and Upsilon(1S) K^+ K^- final states [K.F. Chen et al. (Belle Collaboration), Phys. Rev. Lett. 100, 112001 (2008); I. Adachi et al. (Belle Collaboration), arXiv:0808.2445], yielding good fits. Dimeson invariant mass spectra in these processes are shown to be dominated by the corresponding light scalar and tensor states. The …
We search for evidence of a light scalar boson in the radiative decays of the Upsilon(2S) and Upsilon(3S) resonances: Upsilon(2S,3S)-> gamma A0, A0 -> mu^+ mu^-. Such a particle appears in extensions of the Standard Model, where a light CP-odd Higgs boson naturally couples strongly to b-quarks. We find no evidence for such processes in the mass range 0.212<= m(A0)<= 9.3 GeV in the samples of 99*10^6 Upsilon(2S) and 122*10^6 Upsilon(3S) decays collected by the BABAR detector at the PEP-II B-factory and set stringent upper limits on the effective coupling of the b quark to the A0. We also limit …
Motivated by very recent measurement of the radiative decays of $Υ(1S)$ to $χ_{c1}$ at Belle, we use the nonrelativistic QCD factorization theory and calculate the branching fractions of the radiative decays of bottomonium into S-wave and P-wave charmonium, i.e. $Υ(nS) \to η_c(nS)+γ$ and $Υ(nS)\to χ_{cJ}+γ$. We systematically studied the branching fractions of the radiative decays of bottomonium into charmonium. Compared to the previous calculation, we obtained the analytical expression for the decay widths and considered the color-octet contributions. For $Υ(nS) \to η_c(nS)+γ$, the relativist…
Motivated by concerns regarding possible two-body contributions to the recently-measured inclusive Upsilon(nS)->gamma+X (n=1, 2, 3) direct photon spectra, we report on a new study of exclusive radiative decays of these narrow Upsilon(nS) resonances into two-body final states R+gamma, with R a narrow resonant hadronic state decaying into four or more charged particles. Such two-body processes are not explicitly addressed in the extant theoretical frameworks used to calculate the inclusive direct photon spectra, and must also be explicitly inserted into Monte Carlo simulations. Using data collec…
We present a tetraquark interpretation of the charged bottomonium-like states Z+-_b(10610) and Z+-_b(10650), observed by the Belle collaboration in the pi+- Upsilon(nS) (n=1,2,3) and pi+- h_b(mP) (m=1,2) invariant mass spectra from the data taken near the peak of the Upsilon(5S). In this framework, the underlying processes involve the production and decays of a vector tetraquark Y_b(10890), e+e- --> Y_b(10890) --> [Z+-_b(10610)pi-+, Z+-_b(10650)pi-+] followed by the decays [Z+-_b (10610), Z+-_b (10650)] --> pi+- Upsilon(nS), pi+- h_b(mP). Combining the contributions from the meson loops and an…
The CLEO Collaboration has made the first observations of hadronic transitions among bottomonium (b-bbar) states other than the dipion transitions among upsns states. In our study of Y(3S) decays, we find a significant signal for Y(3S) -> gamma omega Y(1S) that is consistent with radiative decays Y(3S) -> gamma chi_b1,2(2P), followed by chi_b1,2(2P) -> omega Y(1S). The branching ratios we obtain are B(chi_b1(2P) -> omega Y(1S)) = (1.63 +0.35-0.31 +0.16-0.15)% and B(chi_b2(2P) -> omega Y(1S)) = (1.10 +0.32-0.28 +0.11-0.10)%, in which the first error is statistical and the second is systematic.
Continuing our studies of radiative Upsilon(1S) decays, we report on a search for Upsilon to gamma eta and Upsilon to gamma f_{J}(2220) in 61.3 pb^{-1} of e^{+}e^{-} data taken with the CLEO II detector at the Cornell Electron Storage Ring. For the gamma eta search the three decays of the eta meson to pi^{+}pi^{-}pi^{0}, pi^{0}pi^{0}pi^{0}, and gamma gamma were investigated. We found no candidate events in the two (3π)^{0} modes and no significant excess over expected backgrounds in the gamma gamma mode to set a limit on the branching fraction of B(Upsilon to gamma eta) < 2.1 x 10^{-5} at 90% …
It is argued that the observed enhancement of the hadronic transition Upsilon(4S) -> Upsilon(1S) eta relative to Upsilon(4S) -> Upsilon(1S) pi pi can be explained if the resonance Upsilon(4S) contains an admixture of a four-quark component, possibly due to the coupling to the meson channel B \bar B. A test of the discussed mechanism by searching for the transition Upsilon(4S) -> Upsilon(1S) eta'(958) is suggested. Some properties of possible four-quark states related to the suggested one by the heavy quark spin symmetry are also discussed.
Using a well-established effective interaction in a rainbow-ladder truncation model of QCD, we fix the remaining model parameter to the bottomonium ground-state spectrum in a covariant Bethe-Salpeter equation approach and find surprisingly good agreement with the available experimental data including the 2^{--} Upsilon(1D) state. Furthermore, we investigate the consequences of such a fit for charmonium and light-quark ground states.
We review selected recent Belle results in quarkonium physics, that include precision measurement of the eta_b(1S) parameters, evidence for the eta_b(2S); evidence for the psi_2(1D); observation of the psi(4040) and psi(4160) transitions to J/psi eta with anomalously high rates; observation of the Upsilon(5S) transitions to Upsilon(1D)pi+pi- and Upsilon(1S,2S)eta. The low excitations of charmonium and bottomonium are in agreement with the Lattice QCD and effective theories calculations, while high excitations show unexpected properties.
We report on a search for the exclusive two-body charmless hadronic B meson decays B-> eta' rho, B-> eta' K*, B-> eta' phi, B-> eta' omega and B->eta' eta('). The results are obtained from a data sample containing 535 x 10^6 BBbar pairs that were collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ e- collider. We find no significant signals and report upper limits in the range 0.5-6.5 x 10^{-6} for all of the above decays.
We present the first evidence for the production of Upsilon(1D) states in the four-photon cascade, Upsilon(3S)-->gamma chib(2P), chib(2P)-->gamma Upsilon(1D), Upsilon(1D)-->gamma chib(1P), chib(1P)-->gamma Upsilon(1S), followed by the Upsilon(1S) annihilation into e+e- or mu+mu-. The signal has a significance of 10.2 standard deviations. The measured product branching ratio for these five decays, (2.5+-0.5+-0.5)x10^(-5), is consistent with the theoretical estimates. The data are dominated by the production of one Upsilon(1D) state consistent with the J=2 assignment. Its mass is determined to b…
A measurement of the production cross section ratio sigma(chi[b2](1P)) / sigma( chi[b1](1P)) is presented. The chi[b1](1P) and chi[b2](1P) bottomonium states, promptly produced in pp collisions at sqrt(s) = 8 TeV, are detected by the CMS experiment at the CERN LHC through their radiative decays chi[b1,2](1P) to Upsilon(1S) + gamma. The emitted photons are measured through their conversion to electron-positron pairs, whose reconstruction allows the two states to be resolved. The Upsilon(1S) is measured through its decay to two muons. An event sample corresponding to an integrated luminosity of …
We report the observation of B0bar --> D0 eta' and the first observation of B0bar --> D*0 eta', using 140 fb-1 of data collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric energy e+ e- collider. We find the branching fractions to be B(B0bar --> D0 eta') = [ 1.14 +- 0.20(stat) +0.10-0.13(syst)] x 10^-4 and B(B0bar --> D*0 eta') = [ 1.21 +- 0.34(stat) +- 0.22(syst)] x 10^-4 with significances including systematic uncertainty of 8.9 and 5.3 standard deviations, respectively.
We report the results of searches for B+ -> J/psi eta' K+ and B0 -> J/psi eta' Ks0 decays, using a sample of 388 x 10^6 BBbar pairs collected with the Belle detector at the Upsilon(4S) resonance. No statistically significant signal is found for either of the two decay modes and upper limits for the branching fractions are determined to be B(B+ -> J/psi eta' K+) < 8.8 x 10^-5 and B(B0 -> J/psi eta' Ks0) < 2.5 x 10^-5 at 90% confidence level.
Taking into account the new data on the full width of D^{\ast\pm}(2010) and the mass difference of the charged and neutral beauty mesons B^\pm, B^0,\bar B^0, the branching ratios of the decays psi(3770), Upsilon(10580) to pi^+pi^-, K bar K, rho(omega)pi, rho(omega)eta, rho(omega)eta^prime, K^ast bar K+ c.c, rho^+ rho^-, and K^ast bar K^ast are re-evaluated in the model in which the Okubo-Zweig-Iizuka rule is violated due to the real intermediate state D\bar D in case of psi(3770) and B\bar B in case of Upsilon(10580). The inclusive annihilation of psi(3770) and Upsilon(10580) into light hadron…
We present preliminary improved measurements of the branching fractions of the color-suppressed decays B0bar -> D0 h0, where h0 represents the three light neutral mesons pi0, eta and omega. The measurements are based on a data sample of 140fb-1 collected at the Upsilon(4S) with the Belle detector at the KEKB energy-asymmetric e+e- collider, corresponding to seven times the luminosity of the previous Belle measurements.
We report measurements of radiative B decays with K eta gamma final states, using a data sample of 140 /fb recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB e+e- asymmetric energy collider. We observe B -> K eta gamma for the first time with a branching fraction of (6.9 +1.7-1.6 (stat) +1.3-1.0 (syst)) X 10^{-6} for M(Keta) < 2.4 GeV/c2. We also set an upper limit on B -> K3*(1780) gamma.
We report measurements of radiative B decays with K eta gamma final states, using a data sample of 253 /fb recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB e+e- storage ring. We observe B+ -> K+ eta gamma for the first time with a branching fraction of (8.4 +- 1.5(stat) +1.2 -0.9(syst)) X 10^{-6} for M(Keta) < 2.4 GeV/c^2, and find evidence of B0 -> K0 eta gamma. We also search for B -> K3*(1780) gamma.
We present measurements of time-dependent CP-violation asymmetries for the decays B0 to eta'K0. The data sample corresponds to 347 million BBbar pairs produced by e+e- annihilation at the Upsilon(4S) resonance in the PEP-II collider, and collected with the BaBar detector. The preliminary results are S = 0.55+/-0.11+/-0.002, and C = -0.15+/-0.07+/-0.03, where the first error quoted is statistical, the second systematic.
Using 9.0/fb of integrated luminosity in e+e- collisions near Upsilon(4S) mass collected with the CLEO II.V detector we report the first observation of the decay D0 -> K0S ETA PI0 We measure the ratio of branching fractions, BR(D0 -> K0S ETA PI0) / BR(D0 -> K0S PI0) = 0.46 +- 0.07 +- 0.06. We perform a Dalitz analysis of 155 selected D0 -> K0S ETA PI0 candidates and find leading contributions from a_0(980) K0S and K*(892) ETA intermediate states.
We have studied two-photon transitions from Upsilon(3S) decays recorded by the CLEO-III detector in exclusive events with two photons and either two electrons or two muons. We obtain precision measurements of the chi_b(2P_J) masses for J=2 and J=1. The transition rates for all three spin states of the 2P triplet are measured with improved precision which leads to a better determination of their hadronic width ratios. We also observe rare transitions via the chi_b(1P) states. The measured rates for these transitions allow a determination of <1P|r|3S>, the E1 matrix element, which is more sensit…
We present preliminary results of a search for the decay B0 -> eta' phi. The data were recorded with the BaBar detector at the PEP-II asymmetric-energy B-meson Factory at SLAC and correspond to 89 million B B-bar pairs produced in e+e- annihilation at the Upsilon(4S) resonance. We find no evidence for a signal and set a 90% CL upper limit of BF(B0 -> eta' phi) < 1.0 x 10^-6
We present preliminary measurements of the B meson decays B+->etapi+, B+->etaK+, and B0->etaK0. The data were recorded with the BABAR detector at PEP II and correspond to 88.9 million BBbar pairs produced in e+e- annihilation through the Upsilon(4S) resonance. We find the branching fractions B(B+->etapi+) = (4.2 +1.0-0.9 +/- 0.3)x 10^-6 and B(B+->etaK+) = (2.8 +0.8-0.7 +/-0.2)x10^-6. We set a 90% CL upper limit of B(B0->etaK0) < 4.6x10^-6. The time-integrated charge asymmetries are Ach(B+->etapi+) = -0.51 +0.20-0.18 +/-0.01 and Ach(B+->etaK+) = -0.32 +0.22-0.18 +/-0.01.
We present measurements of branching fractions for four previously unobserved B-meson decays with an eta or eta' meson in the final state. The data sample corresponds to 182 million B-Bbar pairs produced from e+e- annihilation at the Upsilon(4S) resonance. We measure the following branching fractions in units of 10^-6: BF(B0 -> eta omega) = 1.2 +/- 0.6 +/- 0.2 (<2.3 at 90% C.L.), BF(B0 -> eta K0) = 2.5 +/-0.8 +/- 0.1, BF(B+ -> eta rho+) = 8.6 +/- 2.2 +/- 1.1, and BF(B+ -> eta' pi+) = 4.2 +/- 1.0 +/- 0.5, where the first error quoted is statistical and the second systematic. The charge asymmetr…
