Related papers: Recent spectroscopy studies at Belle
The first observation of exotic states with a new quark content $c \bar{c} u \bar{s}$ decaying to the $J/\psi K^+$ final state is reported with high significance from an amplitude analysis of the $B^+ \to J/\psi \phi K^+$ decay. The…
Signals consistent with the B$^+_\mathrm{c}$(2S) and B$^{*+}_\mathrm{c}$(2S) states are observed in proton-proton collisions at $\sqrt{s} =$ 13 TeV, in an event sample corresponding to an integrated luminosity of 143 fb$^{-1}$, collected by…
I report recent results on hidden charm spectroscopy from Belle. These include: observation of a near-threshold enhancement in the omega-J/psi invariant mass distribution for exclusive B-->K omega J/psi decays; evidence for the decay…
The three lowest-lying $\Upsilon$ states, i.e. $\Upsilon(1S)$, $\Upsilon(2S)$, and $\Upsilon(3S)$, composed of $b\bar b$ pairs and below the $B\bar B$ threshold, provide a good platform for the researches of hadronic physics and physics…
With the help of the largest data samples of $J/\psi$ and $\psi(2S)$ events ever produced in $e^+e^-$ annihilations, the three singlet charmonium states, $\eta_c(1S)$, $\eta_c(2S)$ and $h_c(1P)$, have been extensively studied at the BESIII…
Semileptonic decays of $B$ mesons that proceed via $b\rightarrow u$ and $b\rightarrow c$ transitions, as well as rare leptonic $B$ decays, are fertile grounds for probing new physics beyond the Standard Model. The Belle II experiment…
The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. The design luminosity of the machine is $8\times 10^{35}$ cm$^{-2}$s$^{-1}$ and…
We are reporting on a search for flavour-changing neutral current decays $D^0 \to \mu^+ \mu^-$ and $D^0 \to e^+ e^-$, and for lepton-flavour violating decays $D^0 \to e^\pm \mu^\mp$, the measurement of $D^+_{(s)} \to K_S^0 \pi^+$ and…
We report a search for $B^{0}$ decays into invisible final states using a data sample of $657 \times 10^{6}$ $B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB $e^{+}e^{-}$ collider. The signal is…
We report BELLE measurements of the exclusive cross sections for the processes e+e-->DD*, e+e-->DD, e+e-->DDpi, the first observation of psi(4415)-> DD*2(2460)bar decay and new state, Y(4660), using ISR. In addition, another cluster of…
We present recent tests of lepton universality as crucial probes of the Standard Model in semileptonic $B$-meson decays at Belle II. All presented analyses use a data sample collected at the $\Upsilon(4S)$ resonance by the Belle II…
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…
The large data sample being recorded with the Belle detector at the $\Upsilon$(5S) energy provides a unique opportunity to study the less-well-known $B_s^{0}$ meson decays. Following our recent measurement of $B_s^{0}\to D_s^{-}\pi^{+}$ in…
The process e+e- to K+K-J/psi is observed for the first time via initial state radiation. The cross section of e+e- to K+K-J/psi for center-of-mass energies between threshold and 6.0 GeV is measured using 673 fb^{-1} of data collected with…
We report a new analysis of double charmonium production in e+ e- annihilation using a data sample collected by the Belle experiment. We confirm our previous observation of the processes e+ e- -> J/psi eta_c (chi_c0, eta_c(2S)) and perform…
Decays of $B$ mesons involving the transition of a $b$ quark into an $s$ quark are good probes of physics beyond the standard model. Such decays are studied at the Belle II experiment, a detector located along the SuperKEKB…
Using samples of 102 million $\Upsilon(1S)$ and 158 million $\Upsilon(2S)$ event samples collected with the Belle detector, we report on the first search for charge-parity-even charmonium and charmonium-like states in $\Upsilon(1S)$ and…
At colliders, neutral long-lived particles can be detected through displaced decay products or as missing energy. Which search strategy is better depends on the particle's decay length just as on the detector properties. We investigate the…
The $b \rightarrow s \gamma$, $b \rightarrow d \gamma$ and $b \rightarrow s \ell^+ \ell^-$ processes are allowed at higher order via the electroweak loop or box diagrams in the Standard model. It is sensitive probe to search for new physics…
The large data sample recorded with the Belle detector at the Y(5S) energy provides a unique opportunity to study the poorly-known $\bs$ meson. Two analyses, performed with a data sample representing an integrated luminosity of 121 /fb, are…