Nature of the axial-vector mesons from their N-c behavior within the chiral unitary approach

By describing within the chiral unitary approach the g-wave interaction of the vector meson nonet with the octet of pseudoscalar Goldstone bosons, we find that the main component of the axial-vector mesons -b(1)(1235), h(1)(1170), h(1)(1380), a(1)(1260), f(1)(1285) and the two states associated to the K-1(1270)- does not follow the QCD dependence on the number of colors for ordinary q (q) over bar mesons.L.S. Geng thanks the Ministerio de Educacion y Ciencia in the Program of estancias de doctores y tecnologos extranjeros for finantial support. This work is partly supported by DGICYT contracts FPA2007-29115-E, FIS2006-03438, FPA2005-02327 and FPA2007-62777, Santander/Complutense contract PR27/05-13955-BSCH, the Fundación Séneca contract 02975/PI/05, the Generalitat Valenciana and the EU Integrated Infrastructure Initiative Hadron Physics Project under contract RII3-CT-2004-506078.Peer reviewe

Weak decays of heavy hadrons into dynamically generated resonances

In this paper, we present a review of recent works on weak decay of heavy mesons and baryons with two mesons, or a meson and a baryon, interacting strongly in the final state. The aim is to learn about the interaction of hadrons and how some particular resonances are produced in the reactions. It is shown that these reactions have peculiar features and act as filters for some quantum numbers which allow to identify easily some resonances and learn about their nature. The combination of basic elements of the weak interaction with the framework of the chiral unitary approach allow for an interpretation of results of many reactions and add a novel information to different aspects of the hadron interaction and the properties of dynamically generated resonances.We would like to thank C. Hanhart and S. Stone for valuable comments on the manuscript. One of us, E. O., wishes to acknowledge support from the Chinese Academy of Science in the Program of Visiting Professorship for Senior International Scientists (Grant No. 2013T2J0012). This work is partly supported by the Spanish Ministerio de Economia y Competitividad and European FEDER funds under the contract numbers FIS2011-28853-C02-01, FIS2011-28853-C02-02, FIS2014-57026-REDT, FIS2014-51948-C2-1-P, and FIS2014-51948-C2-2-P, and the Generalitat Valenciana in the program Prometeo II-2014/068. This work is also partly supported by the National Natural Science Foundation of China under Grant Nos. 11165005, 11565007, 11475227, 11375080 and 11575076. We acknowledge the support of the European Community-Research Infrastructure Integrating Activity Study of Strongly Interacting Matter (acronym HadronPhysics3, Grant Agreement n. 283286) under the Seventh Framework Programme of EU. It is also supported by the Open Project Program of State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, China (No. Y5KF151CJ1). M. D. gratefully acknowledges support from the NSF/PIF Grant No. PHY 1415459 and the NSF/Career grant No. 1452055.Peer reviewe

Isospin 0 and 1 resonances from pi Sigma photoproduction data

Recently we presented a successful strategy to extract the position of the two Lambda ( 1405) poles from experimental photoproduction data on the gamma p -> K+pi(0)Sigma(0) reaction at Jefferson Lab. Following a similar strategy, we extend the previous method to incorporate also the isospin 1 component which allows us to consider in addition the experimental data on gamma p -> K+pi(+/-)Sigma(-/+). The idea is based on considering a production mechanism as model independent as possible and implementing the final state interaction of the final meson-baryon pair based on small modifications of the unitary chiral perturbation theory amplitudes. Good fits to the data are obtained with this procedure, by means of which we can also predict the cross sections for the K- p -> (K) over barN, pi Sigma, and pi Lambda reactions for the different charge channels. Besides the two poles found for the Lambda(1405) resonance, we discuss the possible existence of an isospin 1 resonance in the vicinity of the (K) over barN threshold.This work is partly supported by the Spanish Ministerio de Economia y Competitividad and European FEDER funds under Contract No. FIS2011-28853-C02-01 and the Generalitat Valenciana in the program Prometeo, 2009/090. We acknowledge the support of the European Community-Research Infrastructure Integrating Activity Study of Strongly Interacting Matter (acronym HadronPhysics3, Grant Agreement No. 283286) under the Seventh Framework Programme of EU.Peer reviewe

Method to observe the JP = 2+ partner of the X0(2866) in the B+ → D+D−K+ reaction

We propose a method based on the moments of the DK mass distribution in the B→DDK decay to disentangle the contribution of the 2 state, partner of X(2900) in the D¯K picture for this resonance. Some of these moments show the interference patterns of the X(2900) and X(2900) with the 2 state, which provide a clearer signal of the 2 resonance than the 2 signal alone. The construction of these magnitudes from present data is easy to implement, and based on these data we show that clear signals for that resonance should be seen even with the present statistics

Scalar resonances in the D+ →k-K+K+ decay

We study theoretically the resonant structure of the double Cabibbo suppressed D+→K-K+K+ decay. We start from an elementary production diagram, considered subleading in previous approaches, which cannot produce a final K-K+ pair at the tree level but which we show to be able to provide the strength of the decay through final meson-meson state interaction. The different meson-meson elementary productions are related through SU(3), and the final rescattering is implemented from a suitable implementation of unitary extensions of chiral perturbation theory, which generate dynamically the scalar resonances f0(980) and a0(980). We obtain a good agreement with recent experimental data from the LHCb Collaboration with a minimal freedom in the fit and show the dominance of the a0(980) contribution close to the threshold of the K-K+ spectrum

Helicity amplitudes in the B¯ → D∗ν¯ ττ decay with V-A breaking in the quark sector

In view of the recent measurement of the FLD∗ magnitude in the B¯ → Dν¯ τ reaction we evaluate this magnitude within the standard model and for a family of models with the γ- αγγ current structure for the quarks for different values of α. At the same time we evaluate also the transverse contributions, M= - 1 , M= + 1 , and find that the difference between the M= - 1 and M= + 1 contributions is far more sensitive to changes in α than the longitudinal component. These findings should be looked as an incentive to measure the transverse helicities which are bound to be a far more sensitive magnitude to possible new physics than FLD∗.LRD acknowledges the support from the National Natural Science Foundation of China (Grant Nos. 11975009, 11575076). EO acknowledges the support from the Spanish Ministerio de Economia y Competitividad and European FEDER funds under Contracts No. FIS2017-84038-C2-1-P B and No. FIS2017-84038-C2-2-P B. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 824093 for the STRONG-2020 project

Molecular picture for the X0(2866) as a D⁎K¯⁎ JP = 0+ state and related 1+,2+ states

We recall the predictions made ten years ago about a bound state of J=0 in I=0 of the DK¯ system, which is manifestly exotic, and we associate it to the X(2866) state reported in the recent LHCb experiment. Fine tuning the parameters to reproduce exactly the mass and width of the X(2866) state, we report two more states stemming from the same interaction, one with 1 and the other with 2. For reasons of parity, the 1 state cannot be observed in DK¯ decay, and we suggest to observe it in the DK¯ spectrum. On the other hand, the 2 state can be observed in DK¯ decay but the present experiment has too small statistics in the region of its mass to make any claim. We note that measurements of the DK¯ spectrum and of the DK¯ with more statistics should bring important information concerning the nature of the X(2866) and related ones that could be observed

Tests on the molecular structure of f(2)(1270), f(2)'(1525) from psi(nS) and Upsilon(nS) decays

Based on previous studies that support the vector-vector molecular structure of the f(2)'(1270), f 2 (1525), _ K * 0 2 (1430), f0(1370) and f0(1710) resonances, we make predictions for the.(2S) decay into.(f) f2(1270),.(f) f 2 (1525), K* 0 (892) _ K * 0 2 (1430) and the radiative decay of.(1S),.(2S),.(2S) into.f2(1270),.f 2 (1525),.f0(1370),.f0(1710). Agreement with experimental data is found for three available ratios, without using free parameters, and predictions are done for other cases.We would like to thank Feng Kun Guo for valuable comments. This work is partly supported by National Natural Science Foundation of China (10975068)and the Natural Science Foundation of the Liaoning Scientific Committee. This work is also partly supported by the Spanish Ministerio de Economiay Competitividad and European FEDER funds under the contract number FIS2011-28853-C02-01, and the Generalitat Valenciana in the program Prometeo, 2009/090. We acknowledge the support of the European Community-Research Infrastructure Integrating Activity Study of Strongly Interacting Matter (acronym HadronPhysics3, Grant Agreement no. 283286) under the Seventh Framework Programme of EUPeer reviewe

Radiative decay into gamma-baryon of dynamically generated resonances from the vector-baryon interaction

We study the radiative decay into gamma and a baryon of the SU(3) octet and decuplet of nine and ten resonances that are dynamically generated from the interaction of vector mesons with baryons of the octet and the decuplet, respectively. We obtain quite different partial decay widths for the various resonances, and for different charge states of the same resonance, suggesting that the experimental investigation of these radiative decays should bring much information on the nature of these resonances. For the case of baryons of the octet we determine the helicity amplitudes and compare them with experimental data when available.We would like to thank M. J. Vicente Vacas for a critical reading of the manuscript. This work is partly supported by DGICYT contract number FIS2006-03438. This research is part of the EU Integrated Infrastructure Initiative Hadron Physics Project under contract number RII3-CT-2004-506078. B. X. Sun acknowledges support from the National Natural Science Foundation of China under grant number 10775012.Peer reviewe

Novel Interpretation of the "Theta(+)(1540) Pentaquark" Peak

We use a theoretical model of the gamma d --> K+K- np reaction adapted to the experiment done at LEPS where a peak was observed and associated with the Theta(+)(1540) pentaquark. The study shows that the method used in the experiment to assign momenta to the undetected proton and neutron, together with the chosen cuts, necessarily creates an artificial broad peak in the assumed K(+)n invariant mass in the region of the claimed Theta(+)(1540), such that the remaining strength seen for the experimental peak is compatible with a fluctuation of 2 sigma significance.This work is partly supported by the DGICYT contract FIS2006-03438, the Generalitat Valenciana in the program Prometeo and the EU Integrated Infrastructure Initiative Hadron Physics Project, n.227431. A. M. T thanks the support from a FPU grant of the MICINN.Peer reviewe