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Register a new userNew Measurement of Exclusive Decays of the chi_c0 and chi_c2 to Two-Meson Final States
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Using a sample of 2.59 times 10^7 psi(2S) decays collected by the CLEO--c detector, we present results of a study of chi_{c0} and chi_{c2} decays into two-meson final states. We present the worlds most precise measurements of the chi_{cJ,(J=0,2)} -> pi^+pi^-, pi^0 pi^0, K^+K^-, K^0_S K^0_S, eta eta and eta^{prime} eta^{prime} branching fractions, and a search for chi_c decays into eta eta^{prime}. These results shed light on the mechanism of charmonium decays into pseudoscalar mesons.
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Using samples of 102 million $Upsilon(1S)$ and 158 million $Upsilon(2S)$ events collected with the Belle detector, we study exclusive hadronic decays of these two bottomonium resonances to $ks K^+ pi^-$ and charge-conjugate (c.c.) states, $pi^+ pi^- pi^0 pi^0$, and $pi^+ pi^- pi^0$, and to the two-body Vector-Pseudoscalar ($K^{ast}(892)^0bar{K}^0+ {rm c.c.}$, $K^{ast}(892)^-K^+ + {rm c.c.}$, $omegapi^0$, and $rhopi$) final states. For the first time, signals are observed in the modes $Upsilon(1S) to ks K^+ pi^- + {rm c.c.}$, $pi^+ pi^- pi^0 pi^0$, and $Upsilon(2S) to pi^+ pi^- pi^0 pi^0$, and evidence is found for the modes $Upsilon(1S)to pi^+ pi^- pi^0$, $K^{ast}(892)^0 bar{K}^0+ {rm c.c.}$, and $Upsilon(2S) to ks K^+ pi^- + {rm c.c.}$ Branching fractions are measured for all the processes, while 90% confidence level upper limits on the branching fractions are also set for the modes with a statistical significance of less than $3sigma$. The ratios of the branching fractions of $Upsilon(2S)$ and $Upsilon(1S)$ decays into the same final state are used to test a perturbative QCD prediction for OZI-suppressed bottomonium decays.
We report a search for $B$ decays to selected final states with the $eta_c$ meson: $B^{pm}to K^{pm}eta_cpi^+pi^-$, $B^{pm}to K^{pm}eta_comega$, $B^{pm}to K^{pm}eta_ceta$ and $B^{pm}to K^{pm}eta_cpi^0$. The analysis is based on $772times 10^6$ $Bbar{B}$ pairs collected at the $Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We set 90% confidence level upper limits on the branching fractions of the studied $B$ decay modes, independent of intermediate resonances, in the range $(0.6-5.3)times 10^{-4}$. We also search for molecular-state candidates in the $D^0bar{D}^{*0}-bar{D}^0D^{*0}$, $D^0bar{D}^0+bar{D}^0D^0$ and $D^{*0}bar{D}^{*0}+bar{D}^{*0}D^{*0}$ combinations, neutral partners of the $Z(3900)^{pm}$ and $Z(4020)^{pm}$, and a poorly understood state $X(3915)$ as possible intermediate states in the decay chain, and set 90% confidence level upper limits on the product of branching fractions to the mentioned intermediate states and decay branching fractions of these states in the range $(0.6-6.9)times 10^{-5}$.
The first observation of the $D^0 to pi^+pi^-mu^+mu^-$ and $D^0 to K^+K^-mu^+mu^-$ decays is reported using a sample of proton-proton collisions collected by LHCb at a center-of-mass energy of 8$,$TeV, and corresponding to 2$,$fb$^{-1}$ of integrated luminosity. The corresponding branching fractions are measured using as normalization the decay $D^0 to K^- pi^+[mu^+mu^-]_{rho^0/omega}$, where the two muons are consistent with coming from the decay of a $rho^0$ or $omega$ meson. The results are $mathcal{B}(D^0 to pi^+pi^-mu^+mu^-)=(9.64pm0.48pm0.51pm0.97)times10^{-7}$ and $mathcal{B}(D^0 to K^+K^-mu^+mu^-)=( 1.54pm0.27pm0.09pm0.16)times10^{-7}$, where the uncertainties are statistical, systematic, and due to the limited knowledge of the normalization branching fraction. The dependence of the branching fraction on the dimuon mass is also investigated.
We study exclusive chi_c0, chi_c1 and chi_c2 decays to four-hadron final states involving two charged and two neutral mesons: pi^+pi^-pi^0pi^0, K^+K^-pi^0pi^0, pppi^0pi^0, K^+K^-etapi^0, and K^+-pi^-+K^0pi^0o. The chi_c states are produced in radiative decays of 3.08 million psi-prime resonance decays and observed in the CLEO detector. We also measure the largest substructure contributions to the modes pi^+pi^-pi^0pi^0 and K^+-pi^-+K^0pi^0.
A study of $D^+pi^-$, $D^0 pi^+$ and $D^{*+}pi^-$ final states is performed using pp collision data, corresponding to an integrated luminosity of 1.0 $fb^{-1}$, collected at a centre-of-mass energy of 7 TeV with the LHCb detector. The $D_1(2420)^0$ resonance is observed in the $D^{*+}pi^-$ final state and the $D^*_2(2460)$ resonance is observed in the $D^+pi^-$, $D^0 pi^+$ and $D^{*+}pi^-$ final states. For both resonances, their properties and spin-parity assignments are obtained. In addition, two natural parity and two unnatural parity resonances are observed in the mass region between 2500 and 2800 MeV. Further structures in the region around 3000 MeV are observed in all the $D^{*+}pi^-$, $D^+pi^-$ and $D^0 pi^+$ final states.
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