Light-front approach for heavy pentaquark transitions

The decay B → f 0 (980)K is studied within the framework of QCD factorization and the twoquark scenario for f 0 (980). There are two distinct penguin contributions and their interference depends on the unknown mixing angle θ of strange and nonstrange quark contents of f 0 (980): destructive for 0 < θ < π/2 and constructive for π/2 < θ < π. The QCD sum rule method is applied to evaluate the leading-twist light-cone distribution amplitudes and the scalar decay constant of f 0 . We conclude that the short-distance approach is not adequate to explain the observed large rates of f 0 K − and f 0 K 0 . Among many possible subleading corrections, we study and estimate the contributions from the three-parton Fock states of the f 0 and from the intrinsic gluon inside the B meson. It is found that the spectator gluon of the B meson may play an eminent role for the enhancement of f 0 (980)K. We point out that if f 0 (980) is a four-quark state as widely perceived, there will exist extra diagrams contributing to B → f 0 (980)K. However, in practice it is difficult to make quantitative predictions based on the four-quark picture for f 0 (980) as it involves additional nonfactorizable contributions that are difficult to estimate and the calculations of the decay constant and form factors of f 0 (980) are beyond the conventional quark model.

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“…1(b). 3 As shown in [27], a factor of (−i) is needed in Eq. (2.3) in order for the B → S form factors to be positive.…”

Section: Frameworkmentioning

confidence: 99%

B→f0(980)Kdecays and subleading corrections

Cheng

Yang

2005

Phys. Rev. D

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“…It is noted that P 2 = M 2 0 , p1 · P = e 1 M 0 and p2 · P = e 2 M 0 are used as discussed in Ref. [52] and ϕ = 4( π β 2 ) 3/4 e 1 e 2 x 1 x 2 M 0 exp( −p 2 2β 2 ). All other notations can be found in Refs.…”

Section: A → D S πmentioning

confidence: 99%

“…In the expression, q is the four-momentum of the lighter meson of the decay products, while calculating the hadronic transition matrix element, we deliberately let q 2 vary within a reasonable range, then while obtaining the partial width of X (5568) → B s π , we set q 2 to be the on-shell mass of the produced pion as m 2 π . The factor [52]. The explicit expressions of the effective form factors h A are presented in the Appendix for readers' convenience.…”

Section: The Strong Decays X (5568) → B S π +mentioning

confidence: 99%

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Estimating decay rate of $$X^{{\pm }}(5568)\rightarrow B_s\pi ^{{\pm }}$$ X ± ( 5568 ) → B

2018

Eur. Phys. J. C

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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) → B s π , 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 B s . To further reveal the discrepancy, supposing X (5568) as a molecular state, we calculate the decay rate of X (5568) → B s π + in an extended light front model. Numerically, the theoretically predicted decay width of (X (5568) → B s π + ) is 20.28 MeV which is consistent with the result of the D0 collaboration ( = 18.6 +7.9 −6.1 (stat) +3.5 −3.8 (syst) MeV). Since the resonance is narrow, signals might be drowned in a messy background. In analog, two open-charm molecular states DK and B D named as X a and X b , could be in the same situation. The rates of X a → D s π 0 and X b → B c π 0 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.

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A Janus Logic Gate with Sensing Function

2023

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A layered metastructure (LM) formed by a quasi-periodic arrangement of graphene and isotropic dielectric mediums, which can realize the functions of the tunable logic gate and refractive index (RI) sensing based on spin Hall effect (SHE), is theoretically studied. The asymmetric arrangement of the mediums and the increased angle of the incident electromagnetic waves (EWs) equip the LM with Janus feature. Through the modulation of the graphene chemical potential, the sharp absorption peak (AP) in the terahertz (THz) range can be obtained, and then the AP can be used to implement NOT logic and OR logic respectively corresponding to the forward and backward scales. By locating the incident angle of light corresponding to the SHE displacement peak, the linear measurement relationship between RI and SHE angle can be realized, and the widest RI measurement range is 1-1.4 with the angles changing from 21.88°to 61.84°. Additionally, a good linear range can be achieved, owning the optimum sensitivity (S) up to 153.5°RIU −1 . The RI sensing still strictly follows the logic functions of the forward NOT and backward OR via adjusting the chemical potential of graphene and discriminating the peak value of SHE displacement.

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Light-front approach for heavy pentaquark transitions

Cited by 102 publications

References 71 publications

B→f0(980)Kdecays and subleading corrections

B→f0(980)Kdecays and subleading corrections

Estimating decay rate of $$X^{{\pm }}(5568)\rightarrow B_s\pi ^{{\pm }}$$ X ± ( 5568 ) → B

A Janus Logic Gate with Sensing Function

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