The GlueX experiment has had several run periods with a 9 GeV photon beam, its ultimate goal being the search for exotic hybrid mesons. While we improve our understanding of the GlueX detector needed for a high precision PWA, it is possible to carry out a dark matter search now. Constraints on the allowed coupling versus mass of a dark lepto-phobic boson, a hypothetical state with JPC =...
At present the world's largest sample of 1.3 billion J/psi events was accumulated at the BESIII detector, which provides a unique opportunity to investigate the eta/eta' decays via J/psi radiative or hadronic decays. The eta and eta' hadronic decays are sensitive tools for investigations of pi-pi and eta-pi interactions, symmetry breaking, and serve as a test of Chiral Perturbation Theory. In...
Light neutral meson decays provide a unique laboratory to probe fundamental symmetries. A comprehensive Primakoff experimental program at Jefferson Laboratory (JLab) is aimed at gathering high precision measurements on the two-photon decay widths and the transition form factors at low four-momentum transfer squares of $\pi^0$, $\eta$ and $\eta^{\prime}$ via the Primakoff effect. Completed...
We revisit the treatment of radiative decay processes of light-quark qqbar mesons to a pion in the covariant oscillator quark model. Since the pion has an exceptionally light mass compared with other ground-state hadrons, we have difficulty in dealing with pions within the constituent quark model, including the covariant oscillator quark model. The pion is a pseudo-Nambu-Goldstone boson...
Hadronic B decays without a charm quark constitute a powerful probe to search for physics beyond the standard model as well as provide constraints of CP-violation parameters. We report the final measurements from Belle of the branching fraction and CP asymmetry for the decays B0โฯ0ฯ0, BยฑโK+Kโฯยฑ and preliminary results for BโKS0KS0h+(h=K,ฯ) and Bยฑโฯ+ฯโฯยฑ. All investigations employ the full data...
The mechanisms behind baryonic decays of heavy flavoured particles remain mysterious and challenging to describe theoretically. Interesting properties of such decays include the suppression of branching fractions to two-body final states and threshold enhancements in higher multiplicity decays. The large data sample accumulated by the LHCb experiment between 2011 and 2016 enables a variety of...
The $B$ mesons are the lightest mesons which can decay to various final states containing different baryons. Up to now, the discrepancy between the inclusive branching fraction of all $B$ meson decay modes with at least a couple of baryons in the final state, measured by ARGUS to be $(6.8 +- 0.6)\%$ , and the sum of exclusive baryonic channels, averaged on neutral and positive $B$ mesons at...
We study the relationship between the Dโs0(2317)+ resonance and the decay of the Bc meson into J/ฯDK. In this process, the Bc meson decays first into J/ฯ and the quark pair csยฏ, and then the quark pair hadronizes into DK or D_sฮท components, which undergo final state interaction. This final state interaction, generating the Dโs0(2317)+ resonance, is described by the chiral unitary approach....
Experimental results on three-body charmless non-leptonic B decays have shown a considerable amount of direct CP asymmetry localized in specific regions of the Dalitz plot. In the low hadron-hadron mass region, we recently showed that the final state interactions (FSI) play a very important role, providing through $\pi\pi\to KK$ rescattering the strong phase difference needed for direct CP...
LHCb continues to expand its world-leading sample of charmed hadrons collected during LHCโs Run 1 (2010-2012) and Run 2 (2015- present). This sample is yielding some of the most stringent tests of the Standard Model understanding of charm physics. This includes sensitive searches for direct and indirect CP violation in charm interactions and for charm decays that are heavily suppressed or...
BESIII Collaboration has accumulated the world's largest e+e- collision samples at Ecm = 3.773, 4.009, 4.18 GeV. From analyses of pure leptonic decay D(s)+ -> l+v (l=mu or tau), semileptonic decays of D -> K(pi)l+v (l=e or mu), D+ -> K-pi+e+v, D+ -> omega e+v, D0(+) -> f0(980)e+v, Ds+ -> eta(')e+v, and Ds+ to eta(')e+v, we report the determinations of their absolute branching fractions, CKM...
We study the $D^+_s \to \pi^+ \pi^+ \pi^-$ and $D^+_s \to \pi^+ K^+ K^-$ decays adopting a mechanism in which the $D^+_s$ decays weakly into a $\pi^+$ and a $q\bar{q}$ component, which hadronizes into two pseudoscalar mesons. The final state interactions between these two pseudoscalar mesons is taken into account by using a chiral unitary approach in coupled channels, which gives rise to the...
By solving the Muskhelishvili-Omnes integral equations, coupled-channel effects are taken into account for the scalar form factors of semi-leptonic $D\to\pi$ and $D\to \bar{K}$ transitions, denoted by $f_0^{D\to\pi}$ and $f_0^{D\to\bar{K}}$, respectively. As inputs, we employ the unitarized amplitudes from chiral effective theory for the intermediate region, while, at high energy, proper...
We employ a mathematical framework based on rational approximants
in order to calculate meson form factors. The method profits
from unitary, is systematic and data based, and is able to ascribe a
systematic uncertainty which provides for the desired model independence.
Two examples are discussed: the pseudoscalar-pole piece of the
hadronic light-by-light contribution to the anomalous magnetic...
The phenomenon of CP violation has been observed in the K- and B-meson systems, but not yet with any baryonic particle. Charmless decays of beauty baryons are of particular interest in with this respect, as they receive contributions from both tree- (b->u) and loop-level (b->d and b->s) transitions with similar magnitude. We present the most recent measurements of CP violation observables in b...
In 2014. BESIII collected a data sample of 567 pb-1 at Ecm = 4.6 GeV, which is just above the Lambda_c+ pair production threshold. By analyzing this data sample, we have measured the absolute branching fractions for many decays of Lambda+c for the first time. These decays include the semileptonic decays of Lambda e+v, Lambda mu+v, the hadronic decays of pKs, pK-pi+, pK-pi+pi0, Lambda pi+,...
The $P_c(4380)$ and $P_c(4450)$ states observed recently by LHCb experiment were proposed to be either $\bar{D} \Sigma_c^*$ or $\bar{D}^* \Sigma_c$ bound states. We analyze the decay behaviors of such two types of hadronic molecules within the effective Lagrangian framework. With branching ratios of ten possible decay channels calculated, it is found that the two types of hadronic molecules...
From the perspective that the $\Lambda_c(2595)$ and $\Lambda_c(2625)$ are dynamically generated resonances from the $DN,~D^*N$ interaction and coupled channels, we have evaluated the rates for $\Lambda_b \to \pi^- \Lambda_c(2595)$ and $\Lambda_b \to \pi^- \Lambda_c(2625)$ up to a global unknown factor that allows us to calculate the ratio of rates and compare with experiment, where good...
In this work we calculate the ratios of rates of the $ฮ_b$ nonleptonic and semileptonic decays into the $ฮ_c$(2790) and $ฮ_c$(2815) ($ฮ_c^{*}$) resonances. These resonances are dynamically generated from the pseudoscalar-baryon and vector-baryon interactions, whose mixing is done using the chiral Weinberg-Tomozawa (WT) meson-baryon interaction extended to four flavors. The first part of the...
The BESIII Experiment at the Beijing Electron Positron Collider (BEPC2) has accumulated the world's largest samples of e+e- collisions in the tau-charm region. Using a sample of 106 million psi(3686) decays, the branch fractions of psi(3686) -> gamma chi_c0, gamma chi_c1, gamma chi_c2 are determined to be (9.389 +- 0.014 +- 0.332)%, (9.905 +- 0.011 +- 0.353)%, and (9.621 +- 0.013 +- 0.272)%,...
Electric (E1) and magnetic (M1) dipole transitions have been studied since the early days of hadron spectroscopy because they allow to access heavy quarkonium states which are below open-flavour threshold. Moreover, these reactions are interesting by themselves because they are an important tool to check particular regions of the hadrons' wave function and thus to determine their internal...
The BES data on the $J/\psi \to \eta K^{*0}\bar{K}^{*0}$ reaction show a clear enhancement in the $K^{*0}\bar{K}^{*0}$ mass distribution close to the threshold of this channel. Such an enhancement is usually a signature of a $L=0$ resonance around threshold, which in this case would correspond to an $h_1$ state with quantum numbers $I^G(J^{PC})=0^-(1^{+-})$. We study the state around $1800...
We perform calculations for the $\eta_c \to \eta \pi^+ \pi^-$ decay using elements of SU(3) symmetry to see the weight of different trios of pseudoscalars produced in this decay, prior to the final state interaction of the mesons. After that, the interaction of pairs of mesons, leading finally to $\eta \pi^+ \pi^-$, is done using the chiral unitary approach. We evaluate the...
In heavy quarkonia, hadronic transitions serve as an enlightened probe for the structure and help to establish the understanding of light quark coupling with a heavy degree of freedom. Moreover, in recent years, hadronic transitions revealed remarkable discoveries to identify the new conventional heavy quarkonia and extracting useful information about the so called โXYZโ exotic states.
In...
