1,724,079 research outputs found
X(5568) and its partner states
No full textStimulated by the recent observation of the X(5568), we study the X(5568) and its partners under the tetraquark scenario. In the framework of the color-magnetic interaction, we estimate the masses of the partner states of the X(5568) and discuss their decay pattern, which provides valuable information on the future experimental search of these states.National Natural Science Foundation of China [11275115, 11222547, 11175073, 11261130311]; 973 program; National Youth Top-notch Talent Support Program (Thousands-of-Talents Scheme); SRF for ROCS, SEMSCI(E)[email protected]; [email protected]; [email protected]
Exploring X(5568) as a meson molecule
Get PDFAzizi, Kazem (Dogus Author)The parameters, i.e. the mass and current coupling of the exotic X(5568) state observed by the D0 Collaboration as well as the decay width of the process X→B0sπ+X→Bs0π+ , are explored using the BK¯¯¯¯¯BK¯ molecule assumption on its structure. Employed computational methods include QCD two-point and light-cone sum rules, the latter being considered in the soft-meson approximation. The obtained results are compared with the data of the D0 Collaboration as well as with the predictions of the diquark-antidiquark model. This comparison strengthens a diquark-antidiquark picture for the X(5568) state rather than a meson molecule structure
Resonance X(5568) as an exotic axial-vector state
Get PDFAzizi, Kazem (Doğuş Author)The mass and meson-current coupling constant of the resonance X(5568), as well as the width of the decay X(5568) -> B-s*pi are calculated by modeling the exotic X(5568) resonance as a diquark-antidiquark state X- b = [su][bd] with quantum numbers J(P) = 1(+). The calculations are made employing QCD two-point sum rule method, where the quark, gluon and mixed vacuum condensates up to dimension eight are taken into
account. The sum rule approach on the light-cone in its soft-meson approximation is used to explore the vertex XbBs*pi and extract the strong coupling g(XbBs*pi), which is a necessary ingredient to find the width of the X-b -> B-s*pi(+) decay process. The obtained predictions are compared with the experimental data of the D0 Collaboration, and results of other theoretical works
Width of the exotic Xb (5568) state through its strong decay to Bs0 π+
Get PDFAzizi, Kazem (Dogus Author)The width of the newly observed exotic state Xb(5568) is calculated via its dominant strong decay to Bs0π+ using the QCD sum rule method on the light cone in conjunction with the soft-meson approximation. To this end, the vertex XbBsπ is studied and the strong coupling gXbBsπ is computed employing for Xb(5568) state the interpolating diquark-antidiquark current of the [su][bd] type. The obtained prediction for the decay width of Xb(5568) is confronted and a nice agreement found with the experimental data of the
How can X±(5568) escape detection?
No full textMulti-quark states were predicted by Gell-Mann when the quark model was first formulated. Recently, numerous exotic states that are considered to be multi-quark states have been experimentally confirmed (four-quark mesons and five-quark baryons). Theoretical research indicates that the four-quark state might comprise molecular and/or tetraquark structures. We consider that the meson containing four different flavors sub¯d¯ should exist and decay via the X(5568)→Bsπ channel. However, except for the D0 collaboration, all other experimental collaborations have reported negative observations for X(5568) in this golden portal. This contradiction has stimulated the interest of both theorists and experimentalists. To address this discrepancy, we propose that the assumed X(5568) is a mixture of a molecular state and tetraquark, which contributes destructively to X(5568)→Bsπ. The cancellation may be accidental and it should be incomplete. In this scenario, there should be two physical states with the same flavor ingredients, with spectra of 5344±307 and 6318±315. X(5568) lies in the error range of the first state. We predict the width of the second state (designated as S2) as Γ(XS2→Bsπ)=224±97 MeV. We strongly suggest searching for it in future experiments
Mass and decay constant of the newly observed exotic X(5568) state
No full textAzizi, Kazem (Dogus Author)The mass and decay constant of the X(5568) state newly observed by the D0 Collaboration are computed within the two-point sum rule method using the diquark-antidiquark interpolating current. In calculations, the vacuum condensates up to eight dimensions are taken into account. The obtained result for the mass of the X(5568) state is in a nice agreement with the experimental data
Interpreting the X(5568)
No full textAbstractA variety of options for interpreting the DØ state, X(5568), are examined. We find that threshold, cusp, molecular, and tetraquark models are all unfavoured. Several experimental tests for unravelling the nature of the signal are suggested
Estimating decay rate of X±(5568)→Bsπ± while assuming them to be molecular states
No full textAbstract Discovery of X(5568) brings up a tremendous interest because it is very special, i.e. made of four different flavors. The D0 collaboration claimed that they observed this resonance through portal X(5568)→Bsπ , but unfortunately, later the LHCb, CMS, CDF and ATLAS collaborations’ reports indicate that no such state was found. Almost on the Eve of 2017, the D0 collaboration reconfirmed existence of X(5568) via the semileptonic decay of Bs . To further reveal the discrepancy, supposing X(5568) as a molecular state, we calculate the decay rate of X(5568)→Bsπ+ in an extended light front model. Numerically, the theoretically predicted decay width of Γ(X(5568)→Bsπ+) is 20.28 MeV which is consistent with the result of the D0 collaboration ( Γ=18.6-6.1+7.9(stat)-3.8+3.5(syst) MeV). Since the resonance is narrow, signals might be drowned in a messy background. In analog, two open-charm molecular states DK and BD named as Xa and Xb , could be in the same situation. The rates of Xa→Dsπ0 and Xb→Bcπ0 are estimated as about 30 and 20 MeV respectively. We suggest the experimental collaborations round the world to search for these two modes and accurate measurements may provide us with valuable information
B-s pi-B(K)over-bar interactions in finite volume and X(5568)
No full textThe recent observation of X(5568) by the D0 Collaboration has aroused a lot of interest both theoretically and experimentally. In the present work, we first point out that X (5568) and D-s0* (2317) cannot simultaneously be of molecular nature, from the perspective of heavy-quark symmetry and chiral symmetry, based on a previous study of the lattice QCD scattering lengths of DK and its coupled channels. Then we compute the discrete energy levels of the B-s pi and B (K) over bar system in finite volume using unitary chiral perturbation theory. The comparison with the latest lattice QCD simulation, which disfavors the existence of X(5568), supports our picture where the B-s pi and B (K) over bar interactions are weak and X (5568) cannot be a B-s pi and B (K) over bar molecular state. In addition, we show that the extended Weinberg compositeness condition also indicates that X (5568) cannot be a molecular state made from B-s pi and B (K) over bar interactions.National Natural Science Foundation of China [11375024, 11522539, 11335002, 11411130147]; Fundamental Research Funds for the Central-Universities; Research Fund for the Doctoral Program of Higher Education [20110001110087]; China Postdoctoral Science Foundation [2016M600845]SCI(E)ARTICLE27
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