Search

Abstract In the framework of instantaneous Bethe-Salpeter equation, according to the J PC of quarkonia, we find that their wave functions all contain multiple partial waves, rather than pure waves. In the radiative electromagnetic transitions χ cJ →γψ and χ bJ →γΥ (J = 0, 1, 2), the main wave of quarkonium gives the non-relativistic contribution, while other waves provide the relativistic corrections. Our results indicate that the relativistic effect of charmonium, especially highly excited states, is significant. Such as the relativistic effects of χ cJ (2P) → γψ(1S) (J = 0, 1, 2) are {49.7%, 30.9%, 37.5%}, much larger than the corresponding {17.8%, 7.08%, 12.9%} of χ bJ (2P) → γΥ(1S). The decay of χ cJ (2P) → γψ can be used to distinguish between χ c0(3860) and χ c0(3915), which particle is the charmonium χ c0(2P). Although our result of χ c1(3872)→γψ(2S) is consistent with data, but the one of χ c1(3872)→γψ(1S) is much larger than data, so whether χ c1(3872) is the conventional χ c1(2P) remains an open question. The undiscovered Υ(1D) and Υ(2D) have large production rates in decays of χ b0(2P) → γΥ(1D) and χ bJ (3P) → γΥ(2D) (J = 0, 1), respectively. To search for χ bJ (3P) (J = 0, 1, 2), the most competitive channels are the decays χ bJ (3P) → γΥ(3S). And the best way to find χ b2(1F) is to search for the decay of χ b2(1F) → γΥ(1D).

Abstract In 2021, a new charm-strange meson, $$D_{s0}(2590)^+$$ D s 0 ( 2590 ) + , was discovered, which is believed to be the $$D_s^+(2^1S_0)$$ D s + ( 2 1 S 0 ) . However, its low mass and wide width are challenged by theoretical results. Given the small branching ratio of the current production channel, resulting in a small number of events and large errors, we suggest searching for the $$D_{s0}(2590)^+$$ D s 0 ( 2590 ) + in the B meson nonleptonic decays, $$B_q\rightarrow D^{(*)}_qD_{s0}(2590)^+$$ B q → D q ( ∗ ) D s 0 ( 2590 ) + ( $$q=u,d$$ q = u , d ), followed by $$D_{s0}(2590)^+\rightarrow D^*K$$ D s 0 ( 2590 ) + → D ∗ K . We find that $$Br(B_q\rightarrow D^{(*)}_qD_{s0}(2590)^+)\times Br(D_{s0}(2590)^+\rightarrow D^{*}K)=(2.16\sim 2.82)\times 10^{-3}$$ B r ( B q → D q ( ∗ ) D s 0 ( 2590 ) + ) × B r ( D s 0 ( 2590 ) + → D ∗ K ) = ( 2.16 ∼ 2.82 ) × 10 - 3 is very large, and the result is not sensitive to the mass of $$D_{s0}(2590)^+$$ D s 0 ( 2590 ) + . Due to the large branching ratio, numerous $$D_{s0}(2590)^+$$ D s 0 ( 2590 ) + events are expected. This study is based on the framework of the instantaneous Bethe–Salpeter equation, and the relativistic wave functions used for mesons contain different partial waves. The contributions of the different partial waves are also studied.

Abstract Based on the effective Lagrangian in the heavy quark limit, we calculate the one-boson-exchange interaction kernel of P ψ N 4312 + $$ {P}_{\psi}^N{(4312)}^{+} $$ as the D ¯ Σ c $$ \overline{D}{\Sigma}_c $$ molecular state in isospin- 1 2 $$ \frac{1}{2} $$ . We present the Bethe-Salpeter equation and wave function for the constituent particles to be a (pseudo)scalar meson and a 1 2 $$ \frac{1}{2} $$ baryon. By solving the Bethe-Salpeter equation, we obtain P ψ N 4312 + $$ {P}_{\psi}^N{(4312)}^{+} $$ as the D ¯ Σ c $$ \overline{D}{\Sigma}_c $$ molecular state with J P = 1 2 − $$ {\left(\frac{1}{2}\right)}^{-} $$ . Combining the effective Lagrangian and the obtained BS wave function, the partial decay widths of P ψ N 4312 + $$ {P}_{\psi}^N{(4312)}^{+} $$ to J/ψp, η c p, D ¯ ∗ 0 Λ c + $$ {\overline{D}}^{\ast 0}{\Lambda}_c^{+} $$ and D ¯ 0 Λ c + $$ {\overline{D}}^0{\Lambda}_c^{+} $$ are calculated to be 0.17, 0.085, 8.8, and 0.026 MeV, respectively, which are roughly consistent with the LHCb experimental measurements and some other theoretical researches. The obtain results indicate the fraction of D ¯ ∗ 0 Λ c + $$ {\overline{D}}^{\ast 0}{\Lambda}_c^{+} $$ channel amounts to ~ 90% of P ψ N 4312 + $$ {P}_{\psi}^N{(4312)}^{+} $$ , and is a highly promising channel to be discovered in the near future experiments. Our results favor the interpretation of P ψ N 4312 + $$ {P}_{\psi}^N{(4312)}^{+} $$ as the D ¯ Σ c $$ \overline{D}{\Sigma}_c $$ molecular state with J P = 1 2 − $$ {\left(\frac{1}{2}\right)}^{-} $$ and isospin I = 1 2 $$ \frac{1}{2} $$ .

Terahertz generation from atoms driven by two color linearly polarized (LP) and circularly polarized (CP) laser fields have been well investigated. In this work, based on the photocurrent model, we investigate theoretically the intensity and polarization characteristics of terahertz waves radiated by the bi-elliptical polarized two-color laser fields with orthogonal or parallel major axes. We show that polarization-controlled, including circularly polarized terahertz waves with sufficient intensity comparable to that of co-rotating CP or parallel LP laser field, can be generated by using a longer-wavelength few-cycle bi-elliptical field. Our simulations also show that THz energy and ellipticity can be dramatically improved with dual-color elliptical field with tiny or large ellipticity, compared with that with two-color orthogonal LP field and counter-rotating CP laser field, respectively. Bi-elliptical polarized laser field provides a huge parameter space allowing for far-reaching control of THz emission.

We propose to combine a circularly polarized first-color laser with a linearly polarized second-color laser to control the polarization of THz radiations in the low-frequency region from single-layer graphene. We find that the THz ellipticity can be greatly adjusted by varying the wavelength of second color, and it can be slightly modified by varying the intensity ratio of two colors. We then show that the polarization direction of THz emissions can be dramatically changed by changing the phase difference between two colors. We also identify that the intensity, ellipticity, and polarization direction of THz wave can be changed simultaneously with the time delay between two colors. These can be understood by analyzing the electron currents, intensities of THz emissions in two orthogonal directions, and the phase difference between them. Our proposed scheme can be easily performed in the experiment based on the laser technology nowadays.

Abstract Using an almost complete relativistic method based on the Bethe–Salpeter equation, we study the mixing angle $$\theta $$ θ , the mass splitting $$\bigtriangleup M$$ △ M , the strong decay widths $$\Gamma (D^{({\prime })}_1)$$ Γ ( D 1 ( ′ ) ) and the weak production rates $$Br(B\rightarrow D^{({\prime })}_1\ell \nu _{\ell })$$ B r ( B → D 1 ( ′ ) ℓ ν ℓ ) of the $$D_1(2420)$$ D 1 ( 2420 ) and $$D_1^{\prime }(2430)$$ D 1 ′ ( 2430 ) . We find there is the strong cancellation between the $$^1P_1$$ 1 P 1 and $$^3P_1$$ 3 P 1 partial waves in $$D_1^{\prime }(2430)$$ D 1 ′ ( 2430 ) with $$\theta \sim -\,35.3^{\circ }$$ θ ∼ - 35 . 3 ∘ , which leads to the ‘1/2 vs 3/2’ puzzle. The puzzle can not be overcome by adding only relativistic corrections since in a large parameter range where $$\bigtriangleup M$$ △ M is linear varying and not small, the $$\theta $$ θ , $$\Gamma (D^{({\prime })}_1)$$ Γ ( D 1 ( ′ ) ) and $$Br(B\rightarrow D^{({\prime })}_1\ell \nu _{\ell })$$ B r ( B → D 1 ( ′ ) ℓ ν ℓ ) remain almost unchanged but conflict with data. While in a special range around the mass inverse point where $$\bigtriangleup M=0$$ △ M = 0 and $$\theta =\pm \, 90^{\circ }$$ θ = ± 90 ∘ , they change rapidly but we find the windows where $$\bigtriangleup M$$ △ M , $$\Gamma (D^{({\prime })}_1)$$ Γ ( D 1 ( ′ ) ) and $$Br(B\rightarrow D^{({\prime })}_1\ell \nu _{\ell })$$ B r ( B → D 1 ( ′ ) ℓ ν ℓ ) are all consistent with data. The small $$\bigtriangleup M$$ △ M confirmed by experiment, is crucial to solve the ‘1/2 vs 3/2’ puzzle.

Abstract The relativistic Bethe–Salpeter method is adopted to study the OZI-allowed strong decays of the $$2^+$$ 2 + state $$B^{*}_{2}(5747)^{0}$$ B 2 ∗ ( 5747 ) 0 , with emphasis on the relativistic corrections. We first study the partial waves in the wave functions used and find that there are P, D, and F partial waves in the $$B^{*}_{2}(5747)^{0}$$ B 2 ∗ ( 5747 ) 0 meson, with ratios of $$P/D/F=1:0.421:0.051$$ P / D / F = 1 : 0.421 : 0.051 . We also find that $$S/P/D=1:0.354:0.046$$ S / P / D = 1 : 0.354 : 0.046 for $$B^*$$ B ∗ , and $$S/P=1:0.343$$ S / P = 1 : 0.343 for the B meson. The large components of the D wave in $$B^{*}_{2}(5747)^{0}$$ B 2 ∗ ( 5747 ) 0 and the P wave in $$B^{(*)}$$ B ( ∗ ) mean that large relativistic effects exist in these states. Second, we calculate the strong decays, and the total decay width $$\Gamma (B^{*}_{2}(5747)^{0})=25.9$$ Γ ( B 2 ∗ ( 5747 ) 0 ) = 25.9 MeV and the branching fraction $$\Gamma (B^{*}_{2}(5747)^{0} \rightarrow B^{*}\pi )$$ Γ ( B 2 ∗ ( 5747 ) 0 → B ∗ π ) / $$\Gamma (B^{*}_{2}(5747)^{0} \rightarrow B\pi )=0.96$$ Γ ( B 2 ∗ ( 5747 ) 0 → B π ) = 0.96 obtained are consistent with experimental data. Third, we study the contributions of different partial waves in the initial and final wave functions, and find that the relativistic effects are about $$15\%$$ 15 % and $$11\%$$ 11 % for $$B^{*}_{2}(5747)^{0} \rightarrow B\pi $$ B 2 ∗ ( 5747 ) 0 → B π and $$B^{*}_{2}(5747)^{0} \rightarrow B^{*}\pi $$ B 2 ∗ ( 5747 ) 0 → B ∗ π , respectively, which are much smaller than our expected effects, showing that the relativistic corrections cancel each other in these decays.

Abstract The spectrum and relativistic wave functions of B c system are investigated via solving the complete Salpeter equation. Emphases are put on the study of the partial waves of each J P state. Our study shows that there are three categories of J P states. The first category contains 0 − and 0+ states, which are 1 S 0 dominant state with a small amount of P wave and 3 P 0 dominant state with a small amount of S wave, respectively. The second category includes the natural parity states, such as 1 − , 2+, 3 − , etc. Taking the 1 − state as an example, we study it in two cases. One is the 3 S 1 dominant state with a small amount of P and D waves, and the other is the 3 D 1 dominant state but contains a large amount of S and P wave components. The third category includes the unnatural parity states, such as 1+, 2 − , 3+, etc. For the 1+ spectrum, the states are grouped into pairs with different radial quantum numbers. Each pair contains two 1 P 1 − 3 P 1 mixing states, and the corresponding mixing angles are calculated by using the relativistic wave functions.

Abstract We choose the Reduction Formula, PCAC and Low Energy Theory to reduce the S matrix of a OZI allowed two-body strong decay involving a light pseudoscalar, the covariant transition amplitude formula with relativistic wave functions as input is derived. After confirm this method by the decay $$D^*(2010)\rightarrow D\pi $$ D ∗ ( 2010 ) → D π , we study the newly observed $$D_{s0}(2590)^{+}$$ D s 0 ( 2590 ) + with supposing it to be the state $$D_s(2^1S_0)^+$$ D s ( 2 1 S 0 ) + , we find its decay width $$\Gamma $$ Γ is highly sensitive to the $$D_{s0}(2590)^{+}$$ D s 0 ( 2590 ) + mass, which result in the meaningless comparison of widths by different models with various input masses. Instead of width, we studied the overlap integral over the wave functions of initial and final states, here we parameterized it as X which is model-independent, and the ratio $$\Gamma /{|{\mathbf {P}_f}|^3}$$ Γ / | P f | 3 , both are almost mass independent, to give us useful information. The results show that, all the existing theoretical predictions $$X_{D_s(2S) \rightarrow D^*K}=0.25\sim 0.41$$ X D s ( 2 S ) → D ∗ K = 0.25 ∼ 0.41 and $$\Gamma /{|{\mathbf {P}_f}|^3}=0.81\sim 1.77$$ Γ / | P f | 3 = 0.81 ∼ 1.77 $$\hbox {MeV}^{-2}$$ MeV - 2 are smaller than experimental data $$0.585^{+0.015}_{-0.035}$$ 0 . 585 - 0.035 + 0.015 and $$4.54^{+0.25}_{-0.52}$$ 4 . 54 - 0.52 + 0.25 $$\hbox {MeV}^{-2}$$ MeV - 2 . Further compared with $$X^{ex}_{D^*(2010) \rightarrow D\pi }=0.540\pm 0.009$$ X D ∗ ( 2010 ) → D π ex = 0.540 ± 0.009 , the current data $$X^{ex}_{D_s(2S) \rightarrow D^*K}=0.585^{+0.015}_{-0.035}$$ X D s ( 2 S ) → D ∗ K ex = 0 . 585 - 0.035 + 0.015 is too big to be an reasonable value, so it is early to say $$D_{s0}(2590)^{+}$$ D s 0 ( 2590 ) + is the conventional $$D_s(2^1S_0)^+$$ D s ( 2 1 S 0 ) + meson.

We theoretically study the generation of high-order harmonics and ultrashort isolated attosecond (as) pulses (IAPs) with large ellipticity from the perfectly aligned N2 and O2 molecules driven by the few-cycle orthogonally polarized two-color (OTC) field by numerically solving the reduced two-dimensional time-dependent Schrödinger equation (2D-TDSE). We show that the ellipticity of high-order harmonics strongly depends on the alignment angle and the amplitude ratio of the few-cycle OTC fields. Furthermore, high-order harmonics with large ellipticity are generated at proper alignment angles where ionization events mainly happens at larger laser ellipticities, namely when electrons distribute along the crossing lines in Lissajous diagram of the OTC fields. By superposing the supercontinuum harmonics from N2 and O2 molecules at proper alignment angles, we can directly produce the elliptically polarized IAPs with ellipticity up to 0.76 and the shortest one achieves 141 as. This work demonstrates the possibility for generating the elliptically polarized IAPs with large ellipticity using high-order harmonics from the aligned N2 and O2 molecules exposed to the few-cycle OTC fields.

Abstract Mass spectra and wave functions of the $$J^P=\frac{1}{2}^+$$ J P = 1 2 + (bcq) baryons are calculated by the relativistic Bethe–Salpeter equation (BSE) with considering the mixing effects between the $$1^+$$ 1 + and $$0^+$$ 0 + (bc)-diquarks inside. Based on the diquark picture, the three-body problem of baryons is transformed into two two-body problems. The BSE and wave functions of the $$0^+$$ 0 + diquark are given, and then solved numerically to obtain the effective mass spectra and form factors. Also we present the wave functions at zero point for the (bc)-diquark. Considering the obtained diquark form factors, the (bcq) baryons are then described by the BSE as the bound state of a diquark and a light quark, where the interaction kernel includes the inner transitions between the $$0^+$$ 0 + and $$1^+$$ 1 + diquarks. The general wave function of the $$\frac{1}{2}^+$$ 1 2 + (bcq) baryons is constructed and solved to obtain the corresponding mass spectra. Especially, by using the obtained wave functions, the mixing effects between $$\Xi _{bc}(\Omega _{bc})$$ Ξ bc ( Ω bc ) and $$\Xi _{bc}'(\Omega '_{bc})$$ Ξ bc ′ ( Ω bc ′ ) in ground states are computed and determined to be small ( $$\sim \!1\%$$ ∼ 1 % ). The numerical results indicate that it is a good choice to take $$\Xi _{bc}$$ Ξ bc and $$\Xi '_{bc}$$ Ξ bc ′ as the baryon states with the inside (bc)-diquarks occupying the definite spin.

We reconsider the semileptonic decays of B→D1(′)lν¯l. The previous theoretical calculations predict a significantly smaller rate for the semileptonic decay of B to D1′(Jl=12) compared with that to the D1(Jl=32), which is not consistent with the current experimental data. This conflict is known as the so-called ‘12 vs. 32 puzzle’. In this work, we propose a simple scheme to fix this problem, where we suppose the strong eigenstates D1(′) that do not coincide with the eigenstate of the weak interaction, since no experimental results show that the weak and the strong interactions have to share the same eigenstates. Within the framework of this tentative scheme, meson B first weakly decays to the weak eigenstates Dα(β) and then the latter are detected as the D1(′) by the strong decay products D*π. We predict that there exist two new particles Dα(β) with JP=1+, which were not previously identified. The good performance of the new scheme in describing the experimental data may hint at new symmetry in the weak decays of Bq to 1+ heavy–light mesons. To test the scheme proposed here, we suggest an experiment to detect the difference in the invariant mass spectra of D1 that is reconstructed from the B weak decay and from the strong decay products.

Abstract In this paper, we study the FCNC decay processes of B and $$B_c$$ B c meson, in which one invisible particle is emitted. Both the spin-0 and spin-1 cases are considered. The model-independent effective Lagrangian is introduced to describe the coupling between the light invisible boson and quarks. The constraints of the coupling coefficients are extracted by experimental upper limits of the missing energy in B meson decays. The bounds are used to predict the upper limits of branching fractions of corresponding $$B_c$$ B c decays, which are of the order of $$10^{-6}$$ 10 - 6 or $$10^{-5}$$ 10 - 5 when final meson is pseudoscalar or vector, respectively. The maximum branch ratios are achieved when $$m_\chi \approx 3.5$$ m χ ≈ 3.5 –4 GeV, where $$m_\chi $$ m χ is the mass of the invisible particle.

Abstract We study the CP violation in two-body nonleptonic decays of $$B_c$$ B c meson. We concentrate on the decay channels which contain at least one excited heavy meson in the final states. Specifically, the following channels are considered: $$B_c\rightarrow c{\bar{c}}(2S, 2P)+{\bar{c}}q(1S, 1P)$$ B c → c c ¯ ( 2 S , 2 P ) + c ¯ q ( 1 S , 1 P ) , $$B_c\rightarrow c{\bar{c}}(1S)+{\bar{c}}q(2S, 2P)$$ B c → c c ¯ ( 1 S ) + c ¯ q ( 2 S , 2 P ) , $$B_c\rightarrow c{\bar{c}}(1P)+{\bar{c}}q(2S)$$ B c → c c ¯ ( 1 P ) + c ¯ q ( 2 S ) , $$B_c\rightarrow c{\bar{c}}(1D)+{\bar{c}}q(1S, 1P)$$ B c → c c ¯ ( 1 D ) + c ¯ q ( 1 S , 1 P ) , and $$B_c\rightarrow c{\bar{c}}(3S)+{\bar{c}}q(1S)$$ B c → c c ¯ ( 3 S ) + c ¯ q ( 1 S ) . The improved Bethe-Salpeter method is applied to calculate the hadronic transition matrix element. Our results show that some decay modes have large branching ratios, which is of the order of $$10^{-3}$$ 10 - 3 . The CP violation effect in $$B_c \rightarrow \eta _c(1S)+D(2S)$$ B c → η c ( 1 S ) + D ( 2 S ) , $$B_c \rightarrow \eta _c(1S)+D_0^{*}(2P)$$ B c → η c ( 1 S ) + D 0 ∗ ( 2 P ) , and $$B_c \rightarrow J/\psi +D^{*}(2S)$$ B c → J / ψ + D ∗ ( 2 S ) are most likely to be found. If the detection precision of the CP asymmetry in such channels can reach the $$3\sigma $$ 3 σ level, at least $$10^7$$ 10 7 $$B_c$$ B c events are needed.

Abstract We solved the instantaneous Bethe–Salpeter equation for heavy pseudoscalars in different kernels, where the kernels are obtained using linear scalar potential plus one gluon exchange vector potentials in Feynman gauge, Landau gauge, Coulomb gauge and time-component Coulomb gauge. Since we cannot give a complete QCD-based calculation, the results are gauge dependent. We compared the obtained mass spectra of heavy pseudoscalars between different kernels, found that using the same parameters we obtain the smallest mass splitting in time-component Coulomb gauge, the similar largest mass splitting in Feynman and Coulomb gauges, middle size splitting in Landau gauge.

Abstract Considering Z(3930) and X(4160) as $$\chi _{c2}(2P)$$ χc2(2P) and $$\chi _{c2}(3P)$$ χc2(3P) states, the semileptonic and nonleptonic of $$B_c$$ Bc decays to Z(3930) and X(4160) are studied by the improved Bethe–Salpeter (B–S) Method. The form factors of decay are calculated through the overlap integrals of the meson wave functions in the whole accessible kinematical range. The influence of relativistic corrections are considered in the exclusive decays. Branching ratios of $$B_c$$ Bc weak decays to Z(3930) and X(4160) are predicted. Some of the branching ratios are: $$Br(B_c^+\rightarrow Z(3930)e^+\nu _e)=(3.03^{+0.09}_{-0.16})\times 10^{-4}$$ Br(Bc+→Z(3930)e+νe)=(3.03-0.16+0.09)×10-4 and $$Br(B_c^+\rightarrow X(4160)e^+\nu _e)=(3.55^{+0.83}_{-0.35})\times 10^{-6}$$ Br(Bc+→X(4160)e+νe)=(3.55-0.35+0.83)×10-6 . These results may provide useful information to discover Z(3930) and X(4160) and the necessary information for the phenomenological study of $$B_c$$ Bc physics.

Abstract In this paper, the dilepton electromagnetic decays $$\chi _{cJ}(1P) \rightarrow J/\psi e^+e^-$$ χcJ(1P)→J/ψe+e- and $$\chi _{cJ}(1P) \rightarrow J\psi \mu ^+\mu ^-$$ χcJ(1P)→Jψμ+μ- , where $$\chi _{cJ}$$ χcJ denotes $$\chi _{c0}$$ χc0 , $$\chi _{c1}$$ χc1 and $$\chi _{c2}$$ χc2 , are calculated systematically in the improved Bethe–Salpeter method. The numerical results of decay widths and the invariant mass distributions of the final lepton pairs are given. The comparison is made with the recently measured experimental data of BESIII. It is shown that for the cases including $$e^+e^-$$ e+e- , the gauge invariance is decisive and should be considered carefully. For the processes of $$\chi _{cJ}(1P) \rightarrow J/\psi e^+e^-$$ χcJ(1P)→J/ψe+e- , the branching fraction are: $$\mathcal {B}[\chi _{c0}(1P) \rightarrow J/\psi e^+e^-]=1.06^{+0.16}_{-0.18} \times 10^{-4}$$ B[χc0(1P)→J/ψe+e-]=1.06-0.18+0.16×10-4 , $$\mathcal {B}[\chi _{c1}(1P) \rightarrow J/\psi e^+e^-]=2.88^{+0.50}_{-0.53} \times 10^{-3}$$ B[χc1(1P)→J/ψe+e-]=2.88-0.53+0.50×10-3 , and $$\mathcal {B}[\chi _{c2}(1P) \rightarrow J/\psi e^+e^-]=1.74^{+0.22}_{-0.21} \times 10^{-3}$$ B[χc2(1P)→J/ψe+e-]=1.74-0.21+0.22×10-3 . The calculated branching fractions of $$\chi _{cJ}(1P)\rightarrow J/\psi \mu ^+\mu ^-$$ χcJ(1P)→J/ψμ+μ- channels are: $$\mathcal {B}[\chi _{c0}(1P) \rightarrow J/\psi \mu ^+\mu ^-]=3.80^{+0.59}_{-0.64} \times 10^{-6}$$ B[χc0(1P)→J/ψμ+μ-]=3.80-0.64+0.59×10-6 , $$\mathcal {B}[\chi _{c1}(1P) \rightarrow J/\psi \mu ^+\mu ^-]=2.04^{+0.36}_{-0.38} \times 10^{-4}$$ B[χc1(1P)→J/ψμ+μ-]=2.04-0.38+0.36×10-4 , and $$\mathcal {B}[\chi _{c2}(1P) \rightarrow J/\psi \mu ^+\mu ^-]=1.66^{+0.19}_{-0.19} \times 10^{-4}$$ B[χc2(1P)→J/ψμ+μ-]=1.66-0.19+0.19×10-4 .

Abstract In this paper, we use the instantaneous Bethe–Salpeter method to calculate the semi-leptonic and non-leptonic production of the orbitally excited scalar $$ D_0^* $$ D0∗ in B meson decays. When the final state is 1P state $$ D_0^*(2400) $$ D0∗(2400) , our theoretical decay rate is consistent with experimental data. For $$ D_J^*(3000) $$ DJ∗(3000) final state, which was observed by LHCb collaboration recently and here treated as the orbitally excited scalar $$D^{*}_{0}(2P)$$ D0∗(2P) , its rate is in the order of $$ 10^{-4} \sim 10^{-6}$$ 10-4∼10-6 . We find the special node structure of $$D^{*}_{0}(2P)$$ D0∗(2P) wave function possibly results in the suppression of its branching ratio and the abnormal uncertainty. The 3P states production rate is in the order of $$ 10^{-5}$$ 10-5 .

The experimentally known Bc states are all below open bottom-charm threshold, which experience three main decay modes, and all induced by weak interaction. In this work, we investigate the mass spectrum and strong decays of the Bc(3S) states, which just above the threshold, in the Bethe-Salpeter formalism and P03 model. The numerical estimation gives M(Bc(31S0))=7273MeV, M(Bc⁎(33S1))=7304MeV, Γ(Bc(31S0)→B⁎D)=26.02−2.21+2.33MeV, Γ(Bc⁎(33S1)→BD)=3.39−0.26+0.27MeV, Γ(Bc⁎(33S1)→B⁎D)=14.77−1.33+1.40MeV and Γ(Bc⁎(33S1)→BD⁎)=6.14−0.54+0.58MeV. Compared with previous studies in non-relativistic approximation, our results indicate that the relativistic effects are notable in Bc(3S) exclusive strong decays. According to the results, we suggest to find the Bc(3S) states in their hadronic decays to B and D mesons in experiment, like the LHCb.

Abstract. Background:. Advanced technology has become a valuable tool in etiological studies of intellectual disability/global developmental delay (ID/GDD). The present study investigated the role of genetic analysis to confirm the etiology in ID/GDD patients where the cause of the disease was uncertain in central China. Methods:. We evaluated 1051 ID/GDD children aged 6 months to 18 years from March 2009 to April 2017. Data concerning basic clinical manifestations were collected, and the method of etiology confirmation was recorded. Genome-wide copy number variations (CNVs) detection and high-throughput sequencing of exons in the targeted regions was performed to identify genetically-based etiologies. We compared the incidence of different methods used to confirm ID/GDD etiology among groups with differing degrees of ID/GDD using the Chi-square or Fisher exact probability test. Results:. We recruited 1051 children with mild (367, 34.9%), moderate (301, 28.6%), severe (310, 29.5%), and profoundly severe (73, 6.9%) ID/GDD. The main causes of ID/GDD in the children assessed were perinatal factors, such as acquired brain injury, as well as single gene imbalance and chromosomal gene mutation. We identified karyotype and/or CNVs variation in 46/96 (47.9%) of cases in severe ID/GDD patients, which was significantly higher than those with mild and moderate ID/GDD of 34/96 (35.4%) and 15/96 (15.6%), respectively. A total of 331/536 (61.8%) patients with clear etiology have undergone genetic analysis while 262/515 (50.9%) patients with unclear etiology have undergone genetic analysis (χ2 = 12.645, P

Abstract In this paper, we study the light scalar and pseudoscalar invisible particles in the flavor changing neutral current processes of the B c meson. Effective operators are introduced to describe the couplings between quarks and light invisible particles. The Wilson coefficients are extracted from the experimental results of the B and D mesons, which are used to predict the upper limits of the branching fractions of the similar decay processes for the B c meson. The hadronic transition matrix element is calculated with the instantaneously approximated Bethe-Salpeter method. The upper limits of the branching fractions when m χ taking different values are presented. It is found that at some region of m χ , the channel B c → D s (*) χχ has the largest upper limit which is of the order of 10−6, and for B c → D s * χχ †, the largest value of the upper limits can achieve the order of 10−5. Other decay modes, such as B c → D (*) χχ (†) and B c → B (*) χχ (†), are also considered.

The steel industry is one of the pillar industries in China. The physical and mental health of steel workers is related to the development of China's steel industry. Steel workers have long been working in shifts, high temperatures, noise, highly stressed, and first-line environments. These occupational related factors have an impact on the health of steel workers. At present, the existing hypertension risk scoring models do not include occupational related factors, so they are not applicable to the risk score of hypertension in steel workers. It is necessary to establish a risk scoring model for hypertension in steel workers. In this study, the learning vector quantization (LVQ) neural network algorithm and the FisherSVM coupling algorithm are applied to estimate the hypertension risk of steel workers, and the microscopic laws of the "tailing" phenomenon of the two algorithms are analyzed by means of graphics analysis, which can describe the influence trend of sample size change in different intervals on the classification effect. The results show that the classification accuracy of the algorithm depends on the size of the sample space. When the sample size n ≤ 30 * (k + 1), the Fisher-SVM coupling intelligent algorithm is more applicable. Because its average accuracy rate is 90.00%, the average accuracy of the LVQ algorithm is only 63.34%. When the sample size is n > 30 * (k + 1), the LVQ algorithm is more applicable. Because its average accuracy rate is 93.33%, the average accuracy of the Fisher-SVM coupling intelligent algorithm is only 76.67%. The sample size of this paper is 4422, and the prediction of LVQ neural network model is more accurate. Therefore, based on the relative importance of each risk factor obtained by this model and to establish a steel worker hypertension risk rating scale, the score greater than 18 is considered as the high risk, 12-18 is considered as the medium risk, and less than 12 is considered as the low risk. Through the example's verification, the accuracy rate of the scale is 90.50% and the effect is very good. It shows that the established scoring system can effectively assess the risk of hypertension in steel workers and provide an effective basis for primary prevention of hypertension in steel workers.

Abstract We calculate the two-body strong decays of the orbitally excited scalar mesons $$D_0^*(2400)$$ D0∗(2400) and $$D_J^*(3000)$$ DJ∗(3000) by using the relativistic Bethe–Salpeter (BS) method. $$D_J^*(3000)$$ DJ∗(3000) was observed recently by the LHCb Collaboration, the quantum number of which has not been determined yet. In this paper, we assume that it is the $$0^+(2P)$$ 0+(2P) state and obtain the transition amplitude by using the PCAC relation, low-energy theorem and effective Lagrangian method. For the 1P state, the total widths of $$D_0^*(2400)^{0}$$ D0∗(2400)0 and $$ D_0^*(2400)^+$$ D0∗(2400)+ are 226 and 246 MeV, respectively. With the assumption of $$0^+(2P)$$ 0+(2P) state, the widths of $$D_J^*(3000)^0$$ DJ∗(3000)0 and $$D_J^*(3000)^+$$ DJ∗(3000)+ are both about 131 MeV, which is close to the present experimental data. Therefore, $$D_J^*(3000)$$ DJ∗(3000) is a strong candidate for the $$2^3P_0$$ 23P0 state.

Abstract We give a systematical study on the recently reported excited charm and charm–strange mesons with potential $$1^-$$ 1 - spin–parity, including the $$D^*_{s1}(2700)^+$$ D s 1 ∗ ( 2700 ) + , $$D^*_{s1}(2860)^+$$ D s 1 ∗ ( 2860 ) + , $$D^*(2600)^0$$ D ∗ ( 2600 ) 0 , $$D^*(2650)^0$$ D ∗ ( 2650 ) 0 , $$D^*_1(2680)^0$$ D 1 ∗ ( 2680 ) 0 and $$D^*_1(2760)^0$$ D 1 ∗ ( 2760 ) 0 . The main strong decay properties are obtained in the framework of Bethe–Salpeter (BS) methods. Our results reveal that the two $$1^-$$ 1 - charm–strange mesons can be well described by the further $$2^3\!S_1$$ 2 3 S 1 – $$1^3\!D_1$$ 1 3 D 1 mixing scheme with a mixing angle of $$(8.7^{+3.9}_{-3.2})^\circ $$ ( 8 . 7 - 3.2 + 3.9 ) ∘ . The predicted decay ratio $$\frac{\mathcal {B}(D^*K)}{\mathcal {B}(D~K)}$$ B ( D ∗ K ) B ( D K ) for $$D^*_{s1}(2860)$$ D s 1 ∗ ( 2860 ) is $$0.62^{+0.22}_{-0.12}$$ 0 . 62 - 0.12 + 0.22 . $$D^*(2600)^0$$ D ∗ ( 2600 ) 0 can also be explained as the $$2^3\!S_1$$ 2 3 S 1 predominant state with a mixing angle of $$-(7.5^{+4.0}_{-3.3})^\circ $$ - ( 7 . 5 - 3.3 + 4.0 ) ∘ . Considering the mass range, $$D^*(2650)^0$$ D ∗ ( 2650 ) 0 and $$D^*_1(2680)^0$$ D 1 ∗ ( 2680 ) 0 are more likely to be the $$2^3\!S_1$$ 2 3 S 1 predominant states, although the total widths under the two $$2^3\!S_1$$ 2 3 S 1 and $$1^3\!D_1$$ 1 3 D 1 assignments have no great conflict with the current experimental data. The calculated width for the LHCb $$D^*_1(2760)^0$$ D 1 ∗ ( 2760 ) 0 seems to be about 100 MeV larger than the experimental measurement if taking it as $$1^3\!D_1$$ 1 3 D 1 or $$1^3\!D_1$$ 1 3 D 1 dominant state $$c\bar{u}$$ c u ¯ . The comparisons with other calculations and several important decay ratios are also presented. For the identification of these $$1^-$$ 1 - charm mesons, further experimental information, such as $$\frac{\mathcal {B}(D\pi )}{\mathcal {B}(D^*\pi )}$$ B ( D π ) B ( D ∗ π ) , is necessary.

In this study, the complete mitochondrial genome of Dorcadia ioffi was determined. The mitogenome is 16,785 bp in length and contains 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 1 control region. The nucleotide composition of the D. ioffi mitogenome was A: 40.10%, T: 40.61%, G: 7.74%, C: 11.55%. The A + T content is 80.71%, showing strong AT skew. Phylogenetic analysis indicated that Siphonapteran may have sister relationship with Dipteran.