Abstract: A Sigma* resonance with spin-parity J(P) = 1/2(-) and mass in the vicinity of the (K) over barN threshold has been predicted in the unitary chiral approach and inferred from the analysis of CLAS data on the gamma p -> K+pi(0)Sigma(0) reaction. In this work, based on the dominant Cabibbo favored weak decay mechanism, we perform a study of Lambda(+)(c) -> pi(+)pi(0)Sigma* with the possible Sigma* state decaying into pi(-)Sigma(+) through a triangle diagram. This process is initiated by Lambda(+)(c) -> pi(+)(K) over bar *N, then the (K) over bar* decays into (K) over bar pi and (K) over barN produce the Sigma* through a triangle loop containing (K) over bar *N (K) over bar which develops a triangle singularity. We show that the pi(-)Sigma(+) state is generated from final state interaction of (K) over barN in S-wave and isospin I = 1, and the Lambda(+)(c) -> pi(+)pi(0)pi(-)Sigma(+) decay can be used to study the possible Sigma* state around the (K) over barN threshold. The proposed decay mechanism can provide valuable information on the nature of the Sigma* resonance and can in principle be tested by facilities such as LHCb, BelleII and BESIII.

Abstract: We study the role of the f(1)(1285) resonance in the decays of J/psi -> phi(K) over barK* and J/psi -> f(1) (1285). The theoretical approach is based on the results of chiral unitary theory where the f1(1285) resonance is dynamically generated from the K* (K) over bar -c.c. interaction. In order to further test the dynamical nature of the f(1)(1285) state, we investigate the J/psi -> phi(K) over barK* decay close to the (K) over barK* threshold and make predictions for the ratio of the invariant mass distributions of the J/psi -> phi(K) over barK* decay and the J/psi -> phi f(1)(1285) partial decay width with all the parameters of the mechanism fixed in previous studies. The results can be tested in future experiments and therefore offer new clues on the nature of the f(1) (1285) state.

Abstract: We study the (B) over bar (0)(S) -> J/psi K+ K-, (B) over bar (0) -> J/psi K+ K, B- -> J/psi K+ K-, (B) over bar (0) -> J/psi pi(0)eta(-), decays and compare their mass distributions with those obtained for the (B) over bar (0)(S) -> J/psi pi(+) pi(-) and (B) over bar (0)(S) -> J/psi pi(+)pi(-). The approach followed consist in a factorization of the weak part and the hadronization part into a factor which is common to all the processes. Then what makes the reactions different are some trivial CabibboKobayashi- Maskawa matrix elements and the weight by which the different pairs of mesons appear in a primary step plus their final state interaction. These elements are part of the theory and thus, up to a global normalization factor, all the invariant mass distributions are predicted with no free parameters. Comparison is made with the limited experimental information available. Further comparison of these results with coming LHCb measurements will be very valuable to make progress in our understanding of the meson- meson interaction and the nature of the low lying scalar meson resonances, f(0)(500), f(0)( 980) and a(0)(980).

Abstract: We have studied the J/Psi phi mass distribution of the B+ -> J/Psi phi K+ reaction from threshold to about 4250 MeV, and find that one needs the contribution of the X(4140) with a narrow width, together with the X(4160) which accounts for most of the strength of the distribution in that region. The existence of a clear cusp at the D-s*(D) over bar (s)* threshold indicates that the X(4160) resonance is strongly tied to the D-s*(D) over bar (s)* channel, which finds a natural interpretation in the molecular picture of this resonance.

Abstract: Based on previous studies that support the important role of the N*(2120)D-13 resonance in the gamma p -> K+ A(1520) reaction, we make a re-analysis of this A(1520) photoproduction reaction taking into account the recent CLAS differential cross-section data. In addition to the contact, t-channel (K) over bar exchange, s-channel nucleon pole, and N*(2120) [previously called N*(2080)] resonance contributions, which have been considered in previous works, we also study the u-channel A(1115) hyperon pole term. The latter mechanism has always been ignored in all theoretical analysis, which has mostly relied on the very forward K+ angular LEPS data. It is shown that when the contributions from the N*(2120) resonance and the A(1115) hyperon are taken into account, both the new CLAS and the previous LEPS data can be simultaneously described. We also show that the contribution from the u-channel A(1115) pole term produces an enhancement for large K+ angles, and it becomes more and more relevant as the photon energy increases, being essential to describe the CLAS differential cross sections at backward angles. Furthermore, we find that the new CLAS data also favor the existence of the N*(2120) resonance and that these measurements can be used to further constrain its properties.