Dalitz plot analysis ofηc→K+K−ηand

J. P. Lees¹,

V. Poireau²,

V. Tisserand³

et al.

Abstract

We study the processes γγ → K þ K − η and γγ → K þ K − π 0 using a data sample of 519 fb −1 recorded with the BABAR detector operating at the SLAC PEP-II asymmetric-energy e þ e − collider at center-of-mass energies at and near the ϒðnSÞ (n ¼ 2; 3; 4) resonances. We observe η c → K þ K − π 0 and η c → K þ K − η decays, measure their relative branching fraction, and perform a Dalitz plot analysis for each decay. We observe the K Ã 0 ð1430Þ → Kη decay and measure its branching fraction relative to the Kπ decay mode to be RðK Ã 0 ð1430ÞÞ ¼ BðK Ã 0 ð1430Þ→KηÞ BðK Ã 0 ð1430Þ→KπÞ ¼ 0.092 AE 0.025 þ0.010 −0.025 . The η c → K þ K − η and K Ã 0 ð1430Þ → Kη results correspond to the first observations of these channels. The data also show evidence for η c ð2SÞ → K þ K − π 0 and first evidence for η c ð2SÞ → K þ K − η.

Measurement of the $${\eta _{c}} (1S)$$ production cross-section in $$p $$ $$p $$ collisions at $$\sqrt{s} = 13$$ $$\, \text {TeV}$$

“…It represents the most precise measurement from a single experiment to date. The result is in good agreement with the PDG value [37], the recent BES III result [53], the latest BaBar measurement [54] and LHCb measurements [18,33,36].…”

Dalitz analysis of D0→K−π+η decays at Belle

“…A more precise measurement of this branching fraction from D 0 → K − π þ η decays would test the theoretical predictions. The K Ã 0 ð1430Þ AE → K AE η decay was observed by the BABAR experiment [7] and is awaiting confirmation. Experimentally, the ratio of K Ã 0 ð1430Þ decaying into Kη and Kπ is 0.09 þ0.03 −0.04 [6], which is consistent with the theoretical prediction of 0.05 [8] which was made with the assumption that it is a pure 1 3 P 0 state.…”

Contributions of $$ {K}_0^{\ast } $$(1430) and $$ {K}_0^{\ast } $$(1950) in the three-body decays B → Kπh

“…Because of the large errors for B 0 → η c K * 0 (1950) 0 , we can not extract the decay constant f K * 0 (1950) from this measurement. While from the data of the fit fractions for η c → K 0 S K ± π ∓ in [86] and η c → K + K − π 0 in [92] both from BaBar, one can expect a larger value than 0.0414 GeV 3 for the f…”

“…To describe the slowly increasing phase as a function of the Kπ invariant mass, the scalar Kπ scattering amplitude was written as the relativistic Breit-Wigner term [88] for the resonance K * 0 (1430) in the LASS parametrization together with an effective range nonresonant component in [81], and the effective range term has been applied a cutoff to the slowly varying part close to the charm hadron mass at about 1.8 GeV for the threebody B decays in the experimental studies [38,40,42,43]. At about 1.95 GeV one will find the presence of the resonance K * 0 (1950) in [81] and also in the η c decays in [86,92]. This state was assigned as a radial excitation of the 0 + member of the L = 1 triplet in the LASS analysis [81].…”