Surface reactions of 2,5-diethynyl-1,4-bis(phenylethynyl)benzene on Ag(111), Ag(110), and Ag(100) were systematically explored and scrutinized by scanning tunneling microscopy, molecular mechanics simulations, and density functional theory calculations. On Ag(111), Glaser coupling reaction became dominant, yielding one-dimensional molecular wires formed by covalent bonds. On Ag(110) and Ag(100), however, the terminal alkynes reacted with surface metal atoms, leading to one-dimensional organometallic nanostructures. Detailed experimental and theoretical analyses revealed that such a lattice dependence of the terminal alkyne reaction at surfaces originated from the matching degree between the periodicities of the produced molecular wires and the substrate lattice structures.

Inspired by the newly observed Ξ 0 c states by the LHCb Collaboration, we investigate the OZI-allowed twobody strong decays of the λ-mode 1P wave Ξ ′ c states within the chiral quark model. Our results indicate that: (i) the newly observed states Ξ c (2923) 0 and Ξ c (2939) 0 are good candidates of the λ-mode 1P wave Ξ ′ c states with the spin-parity J P = 3/2 − , namely | 4 P λ 3/2 − and | 2 P λ 3/2 − , respectively. (ii) The another newly observed state Ξ c (2965) 0 mostly corresponds to the λ-mode 1P-wave Ξ ′ c state with the spin-parity J P = 5/2 − , namely | 4 P λ 5/2 − . (iii) For the two λ-mode J P = 1/2 − mixed states, the |P λ 1/2 − 1 is a narrow state with a width of Γ ∼ 15 MeV and mainly decays into Ξ ′ c π; while the |P λ 1/2 − 2 state has a width of Γ ∼ 52 MeV and dominantly decays into Ξ c π and Λ c K channels. If the broad structure around 2880 MeV observed at LHCb arises from the new Ξ 0 c state, this state is very likely to be the |P λ 1/2 − 2 state. m[Ξ c (2939) 0 ] = 2938.55 ± 0.52 MeV, Γ[Ξ c (2939) 0 ] = 10.2 ± 1.9 MeV, m[Ξ c (2965) 0 ] = 2964.88 ± 0.54 MeV, Γ[Ξ c (2965) 0 ] = 14.1 ± 2.2 MeV. As pointed out in Ref. [12], the Ξ c (2930) 0 observed in B − → K − Λ + cΛ −

The strong decay properties of the higher excited heavy-light mesons from the first radially excited states up to the first F-wave states are studied in a constituent quark model. It is found that many missing excitations have good potentials to be found in future experiments for their narrow widths, and some of them dominantly decay into the first orbital excitations rather than into ground states. In future observations, one should focus on the decay processes not only into the ground states, but also into the low-lying P-wave excitations with J P ¼ 0 þ ; 1 þ . Furthermore, the nature of the newly observed states D J ð3000Þ, D Ã J ð3000Þ, and Bð5970Þ is discussed. It is predicted that D J ð3000Þ seems to be a partner of D sJ ð3040Þ, which could be identified as the low-mass mixed state j2P 1 i L (J P ¼ 1 þ ) via the 2 1 P 1 -2 3 P 1 mixing. The D Ã J ð3000Þ resonance seems to favor the 1 3 F 4 state; while the quantum numbers J P ¼ 0 þ and 2 þ cannot be excluded complectly, more experimental observations are needed to determine its J P values. The Bð5970Þ resonance is most likely to be the 1 3 D 3 with J P ¼ 3 − . PHYSICAL REVIEW D 90, 074029 (2014) 074029-2 LI-YE XIAO AND XIAN-HUI ZHONG PHYSICAL REVIEW D 90, 074029 (2014) 074029-4 STRONG DECAYS OF HIGHER EXCITED HEAVY-LIGHT … PHYSICAL REVIEW D 90, 074029 (2014) 074029-9

The strong decays of charm-strange baryons up to N = 2 shell are studied in a chiral quark model. The theoretical predictions for the well determined charm-strange baryons, Ξ *

Inspired by the newly observed Ωð2012Þ state at Belle II, we investigate the two-body strong decays of Ω baryons up to N ¼ 2 shell within the chiral quark model. Our results indicate that (i) the newly observed Ωð2012Þ state could be assigned to the spin-parity J P ¼ 3=2 − state j70; 2 10; 1; 1; 3 2 − i and the experimental data can be reasonably described. However, the spin-parity J P ¼ 1=2 − state j70; 2 10; 1; 1; 1 2 − i and spin-parity J P ¼ 3=2 þ state j56; 4 10; 2; 0; 3 2 þ i cannot be completely excluded.(ii) The D-wave states in the N ¼ 2 shell are most likely to be narrow states with a width of dozens of MeV and have a good potential to be observed in the ΞK and/or Ξð1530ÞK channels in future experiments. The Ωð2250Þ resonance listed in PDG may be a good candidate for the J P ¼ 5=2 þ 1D wave state j56; 4 10; 2; 2; 5=2 þ i.