Related papers: Why the f(0)(980) is mostly ssbar
We present preliminary results of a search for the decay B^0 --> a_0^+(980)pi^- among 22.7 million Upsilon(4S)-->B-anti-B pairs collected by the BABAR detector at PEP-II. Using improved background suppression techniques and optimal signal…
An analysis of semileptonic decays of $B$ mesons with the emission of a single soft pion is presented in the framework of the heavy-quark limit using an effective Lagrangian which implements chiral and heavy-quark symmetries. The analysis…
The hadronic charmless B decays into a scalar meson and a vector meson are studied within the framework of QCD factorization. The main results are: (i) The decay rates for the $f_0(980)K^{*-}$ and $f_0(980)\ov K^{*0}$ modes depend on the…
It is shown that the values of the ratios $\mathcal{B}(D^0\to a_0(980)^+\pi^-)/\mathcal{B} (D^0\to a_0(980)^-\pi^+ )$ and $\mathcal{B}(D^+\to a_0(980)^+\pi^0)/\mathcal{B} (D^+\to a_0(980)^0 \pi^+)$, recently measured by the BESIII…
The results of several studies of charmed mesons and baryons at BABAR are presented. First, searches for the rare decays D0 --> l+ l- are presented and new upper limits on these processes are established. Second, a measurement of the…
Weak emission line quasars are a rare and puzzling group of objects. In this paper we present one more object of this class found in the Sloan Digital Sky Survey (SDSS). The quasar SDSS J094533.99+100950.1, lying at z = 1.66, has…
The very recently observed D^*_{sJ}(2317)^+ meson is described as a quasi-bound scalar c\bar{s} state in a unitarized meson model, owing its existence to the strong ^3P_0 OZI-allowed coupling to the nearby S-wave DK threshold. By the same…
We report the first observation of $a^{0}_{0}(980)$-$f_{0}(980)$ mixing in the decays of $J/\psi\to\phi f_{0}(980)\to\phi a^{0}_{0}(980)\to\phi\eta\pi^{0}$ and $\chi_{c1}\to a^{0}_{0}(980)\pi^{0}\to…
The interactions between the f_0(980) and a_0(980) scalar resonances and the lightest pseudoscalar mesons are studied. We first obtain the interacting kernels, without including any ad hoc free parameter, because the lightest scalar…
We calculate partial widths for the decays a_0(980)\to\gamma\gamma and f_0(980)\to\gamma\gamma under the assumption that a_0(980) and f_0(980) are members of the basic 1^3P_0 q\bar q nonet. The results are in a reasonable agreement with…
We perform simultaneous calculations of the radiative decays of scalar mesons f_0(980)-> \gamma\gamma, a_0(980)-> \gamma\gamma, vector meson \phi(1020)-> \gamma f_0(980), \gamma a_0(980), \gamma \pi^0, \gamma \eta, \gamma \eta' and tensor…
The Belle Collaboration recently discovered the first manifestly exotic meson: Z^+(4430), which decays into psi' pi^+ and therefore has quark content c c-bar u d-bar. The proximity of its mass to the D_1 D-bar^* threshold has motivated the…
We present recent results on scalar light mesons based on Dalitz plot analyses of charm decays from Fermilab experiment E791. Scalar mesons are found to have large contributions to the decays studied, $D^+\to K^-\pi^+\pi^+$ and $D^+,…
The inclusive decay rate into pions of the charmed $D_s$ meson is surprisingly larger than estimates expected from the $W$ annihilation, adopting commonly used values of current-algebra up and down quark masses. We then go beyond this tree…
Based on a dataset acquired by the BaBar experiment running on and near the $\Upsilon(4S)$ resonance from 1999-2002, limits are set on the rate of $D^0$-- $\kern 0.2em\bar{\kern -0.2em D}{}^0$ mixing using the decay mode $D^{*+} \to D^0…
The $B_s^0 \to J/\psi \phi$ and $B_s^0 \to J/\psi f_0(980)$ decays are analyzed within generalized QCD factorization including all leading-order corrections in $\alphas$. We point out that the ratio of our calculated widths, $\Gamma…
The positive parity scalar D$_{s0}^*$(2317) and axial-vector D$_{s1}^*$(2460) charmed strange mesons are generated by coupled-channel dynamics through the s-wave scattering of Goldstone bosons off the pseudoscalar and vector D(D$_s$)-meson…
The $\kappa/K_0^*(700)$ meson remains the most elusive among the light scalar resonances, with its presence in weak decays obscured by limited precision in branching fraction measurements. As a result, the true nature of the $\kappa$…
The signs and values of the two-photon couplings $F_{M\gamma\gamma}$ of mesons $(M)$ and their couplings $g_{MNN}$ to the nucleon as entering into the $t$-channel parts of the difference of the electromagnetic polarizabilities…
Within the increasing experimental evidence of the existence of the I=0 scalar low mass and wide \sigma meson, we review the {\it first} analysis of its quark and gluon substructure from QCD spectral sum rules and some low-energy theorems.…