Model-Independent Study of Structure in B+→D+D−K+ Decays

DK I = 0, $$ D\overline{K} $$ I = 0, 1 scattering and the $$ {D}_{s0}^{\ast } $$(2317) from lattice QCD

“…An axial-vector state, D s1 (2460), was also discovered [4] and similarly does not fit easily into expectations based on a quark model. While this article was being finalised, LHCb announced the observation of a structure in the exotic-flavour D − K + (csdu) channel at an energy ∼ 2.9 GeV [5][6][7].…”

“…Considering the first excited levels in [100]E 2 and [110]B 2 which have dominant overlap with D * K operators and fermion-bilinear operators subduced from J P = 1 + , we can make a rough estimate of the J P = 1 + amplitude. 6 The [100]E 2 level is found at a t E cm = 0.4087(4) corresponding to a t k cot δ = −0.0233 (14), and the [110]B 2 level is found at a t E cm = 0.4088(5) corresponding to a t k cot δ = −0.0242 (14). These values imply large negative scattering lengths (a 1 + ≈ −40a t ), usually indicative of a near-threshold pole.…”

“…Instead using the results for a 0 and r 0 in eq. (5.10) gives Z ≈ 0.13 (6) and Z ≈ 0.14(3) respectively, whereas using eq. (6.3) gives Z ≈ 0.14(3).…”

Charmonium-like resonances with JPC = 0++, 2++ in coupled $$ \mathrm{D}\overline{\mathrm{D}} $$, $$ {\mathrm{D}}_{\mathrm{s}}{\overline{\mathrm{D}}}_{\mathrm{s}} $$ scattering on the lattice

“…In the energy region around 3.9 GeV, above the threshold, one expects a corresponding excited state. So far, three hadrons have been observed with the possible assignment of J P C = 0 ++ : the X(3860), a broad resonance detected by Belle [1,2], and two narrow resonances just below the D sDs threshold -the χ c0 (3930) discovered in the DD channel by LHCb [3,4] and the X(3915) observed through it's decay into J/ψω [5][6][7][8] (with the assignment of J P C = 0 ++ or 2 ++ ). While the latter two resonances could be the same state, their narrowness may indicate exotic content, where X(3915) has been interpreted as ccss meson in ref.…”

Mass spectrum and strong decays of tetraquark $${\bar{c}}{\bar{s}} qq$$ states

“…Recently, the LHCb collaboration reported an enhancement on the D − K + invariant mass distribution in the process B + → D + D − K + , which is parameterized as two Breit-Wigner resonances [1][2][3]: a e-mail: wgj@pku.edu.cn (corresponding author) b e-mail: lmeng@pku.edu.cn c e-mail: lyxiao@ustb.edu.cn d e-mail: oka@post.j-parc.jp e e-mail: zhusl@pku.edu.cn with J P = 0 + and J P = 1 − , respectively. Since they were observed in the D − K + channel, the minimal quark contents arecsdu.…”