Search

In a covariant quark-diquark model, we investigate the rare decay of $\Lambda_b \rightarrow n l^+ l^-$ and $\Lambda_b \rightarrow n \gamma$ in the Bethe-Salpeter equation approach. In this model the baryons are treated as bound states of a constituent quark and a diquark interacting via a gluon exchange and the linear confinement. We find that the ratio of form factors $R$ is varies from $-0.90$ to $-0.25$ and the branching ratios $Br(\Lambda_b \rightarrow n l^+ l^-)\times 10^{8}$ are $6.79(l=e),~4.08 ~ (l=\mu),~2.9 ~(l=\tau) $ and the branching ratio $Br(\Lambda_b \rightarrow \gamma)\times 10^{7} )=3.69$ in central values of parameters., Comment: arXiv admin note: text overlap with arXiv:1911.08023

In this work, we study the BK¯ molecule in the Bethe-Salpeter (BS) equation approach. With the kernel containing one-particle-exchange diagrams and introducing two different form factors (monopole form factor and dipole form factor) in the vertex, we solve the BS equation numerically in the covariant instantaneous approximation. We investigate the isoscalar and isovector BK¯ systems, and we find that X5568 cannot be a BK¯ molecule.

Despite the large baryon-anti-baryon asymmetry in the observable Universe, the closely related phenomenon -- the violation of the combined charge and parity symmetry ($C\!P$V) -- has not been observed in the baryon sector in laboratories. In this paper, a new strategy for searching for $C\!P$V in heavy hadron multi-body decays is proposed, in which a set of novel observables measuring $C\!P$V in such decays -- the partial wave $C\!P$ asymmetries (PW$C\!P$As) -- are introduced. This strategy is model-independent and applicable to multi-body decays of heavy hadrons with arbitrary spin configurations in both initial and final states, and with any number of particles in the final state. It is especially applicable for $C\!P$V investigations in multi-body decays of heavy baryons. As applications of this strategy, we suggest to measure the PW$C\!P$As in some decay channels of bottom baryons such as $\Lambda_b^0\to p \pi^-\pi^+\pi^-$, $\Lambda_b\to p K^- \pi^+\pi^-$, $\Lambda^0_b\to p\pi^-K^+K^-$, $\Lambda_b^0\to\Lambda K^+\pi^-$, and $\Lambda_b^0\to p \pi^- K_s$.}, Comment: 15 pages, 4 figures, 2 tables, accepted for publication in JHEP

We interpret the $X_1(2900)$ as an $S$-wave $\bar{D}_1K$ molecular state in the Bethe-Salpeter equation approach with the ladder and instantaneous approximations for the kernel. By solving the Bethe-Salpeter equation numerically with the kernel containing one-particle-exchange diagrams and introducing three different form factors (monopole, dipole, and exponential form factors) in the verties, we find the bound state exists. We also study the decay width of the decay $X_1(2900)$ to $D^-K^+$., Comment: 13 pages, 4 figures. arXiv admin note: text overlap with arXiv:2004.14085, arXiv:1906.09002

We study the possible bound states of the $D_1D$ system in the Bethe-Salpeter (BS) formalism in the ladder and instantaneous approximations. By solving the BS equation numerically with the kernel containing one-particle exchange diagrams and introducing three different form factors (monopole, dipole, and exponential form factors) at the vertices, we investigate whether the isoscalar and isovector $D_1D$ bound states may exist, respectively. We find that $Y(4260)$ could be accommodated as a $D_1D$ molecule, whereas the interpretation of $Z_2^+(4250)$ as a $D_1D$ molecule is disfavored. The bottom analog of $Y(4260)$ may exist but that of $Z_2^+(4250)$ does not., 17 pages, 6 figures, and 4 tables

The semileptonic decay of heavy flavor mesons offers a clean environment for extraction of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements, which describes the CP-violating and flavor changing process in the Standard Model. The involved form factors where the dynamical information is encoded play an essential role in achieving any conclusive statement. That is, the knowledge of the form factors should be under good control, requiring one to examine more observables in addition to the branching fraction. In this paper, we provide the mean value and the $q^2$-dependent shape for further observables [differential decay distribution ($d\Gamma/dq^2$), forward-backward asymmetry ($\mathcal{A}_{FB}^l$), longitudinal ($P_L^l$) and transverse ($P_T^l$) polarization of a charged lepton, longitudinal polarization of a vector meson in the final state ($F_L^l(V)$), leptonic convexity parameter ($C_F^l$), and trigonometric moments ($W_i^l$) in the decay of $D_{(s)}$ and $B_{(s)}$ to $P/V l^+ \nu_l$ ($l=e$, $\mu$ or $\tau$)], based on the predictions of the relevant form factors from the covariant light-front quark model. $P$ and $V$ denote the pseudoscalar and vector meson, respectively. As a comparison, we find a good agreement with the results from the covariant confining quark model and the relativistic quark model in the literature. As it has been observed that the $P_L^l$ and $F_L^l(V)$ are crucial quantities to discriminate various New Physics models, the reexamination of these observables from a different method is also essential and necessary., Comment: final version, will appear in JHEP soon

The disappearance of reactor $$\bar{\nu }_e$$ ν ¯ e observed by the Daya Bay experiment is examined in the framework of a model in which the neutrino is described by a wave packet with a relative intrinsic momentum dispersion $$\sigma _\mathrm{{rel}}$$ σ rel . Three pairs of nuclear reactors and eight antineutrino detectors, each with good energy resolution, distributed among three experimental halls, supply a high-statistics sample of $$\bar{\nu }_e$$ ν ¯ e acquired at nine different baselines. This provides a unique platform to test the effects which arise from the wave packet treatment of neutrino oscillation. The modified survival probability formula was used to fit Daya Bay data, providing the first experimental limits: $$2.38 \times 10^{-17}< \sigma _\mathrm{{rel}} < 0.23$$ 2.38 × 10 - 17 < σ rel < 0.23 . Treating the dimensions of the reactor cores and detectors as constraints, the limits are improved: $$10^{-14} \lesssim \sigma _\text {rel} < 0.23$$ 10 - 14 ≲ σ rel < 0.23 , and an upper limit of $$\sigma _\text {rel}

We interpret the ${B}_{s1}(5778)$ as an $S$-wave ${B}^{*}\overline{K}$ molecular state in the Bethe-Salpeter equation approach. In the ladder and instantaneous approximations, and with the kernel containing one-particle-exchange diagrams and introducing three different form factors (monopole, dipole, and exponential form factors) in the vertex, we find the bound state exists. We also study the decay widths of the decay ${B}_{s1}(5778)\ensuremath{\rightarrow}{B}_{s}^{*}\ensuremath{\pi}$ and the radiative decays ${B}_{s1}(5778)\ensuremath{\rightarrow}{B}_{s}\ensuremath{\gamma}$ and ${B}_{s1}(5778)\ensuremath{\rightarrow}{B}_{s}^{*}\ensuremath{\gamma}$, which will be instructive for the forthcoming experiments.

A doubly heavy baryon can be regarded as composed of a heavy diquark and a light quark. In this picture, we study the masses of the doubly heavy diquarks in the Bethe-Salpeter (BS) formalism first, which are then used as one of the inputs in studying the masses of the doubly heavy baryons in the quark-diquark model. We establish the BS equations for both the heavy diquarks and the heavy baryons with and without taking the heavy quark limit, respectively. These equations are solved numerically with the kernel containing the scalar confinement and one-gluon-exchange terms. The mass of the doubly charmed baryon Ξcc(⁎) is obtained in both approaches, 3.60∼3.65GeV (Ξcc(⁎)) under the heavy quark limit, 3.53∼3.56GeV for Ξcc and 3.61∼3.63GeV for Ξcc⁎ without taking the heavy quark limit. The masses of Ξbc′, Ξbc(⁎), Ξbb(⁎), Ωcc(⁎), Ωbc′, Ωbc(⁎) and Ωbb(⁎) are also predicted in the same way. We find that the corrections to the results in the heavy quark limit are about −0.02GeV∼−0.11GeV for the masses of the doubly heavy baryons.

In this work, we assume that the observed state $\Xi(1620)$ is a $s$-wave $\Lambda\bar{K}$ or $\Sigma\bar{K}$ bound state. Based on this molecule picture, we establish the Bethe-Salpeter equations for $\Xi(1620)$ in the ladder and instantaneous approximations. We solve the Bethe-Salpeter equations for the $\Lambda\bar{K}$ and $\Sigma\bar{K}$ systems numerically and find that the $\Xi(1620)$ can be explained as $\Lambda\bar{K}$ and $\Sigma\bar{K}$ bound states with $J^P=1/2^-$, respectively. Then we calculate the decay widths of $\Xi(1620)\rightarrow\Xi\pi$ in these two different molecule pictures systems, respectively., Comment: arXiv admin note: text overlap with arXiv:1710.07424

In this work, we study the localized $CP$ violation in ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ and ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}\ensuremath{\sigma}(600)$ decays by employing the quasi-two-body QCD factorization approach. Both the resonance and the nonresonance contributions are studied for the ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decay. The resonance contributions include those not only from $[\ensuremath{\pi}\ensuremath{\pi}]$ channels including $\ensuremath{\sigma}(600)$, ${\ensuremath{\rho}}^{0}(770)$ and $\ensuremath{\omega}(782)$ but also from $[K\ensuremath{\pi}]$ channels including ${K}_{0}^{*}(700)(\ensuremath{\kappa})$, ${K}^{*}(892)$, ${K}_{0}^{*}(1430)$, ${K}^{*}(1410)$, ${K}^{*}(1680)$ and ${K}_{2}^{*}(1430)$. By fitting the four experimental data ${\mathcal{A}}_{\mathcal{C}\mathcal{P}}({K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})=0.678\ifmmode\pm\else\textpm\fi{}0.078\ifmmode\pm\else\textpm\fi{}0.0323\ifmmode\pm\else\textpm\fi{}0.007$ for ${m}_{{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}}^{2}l15\text{ }\text{ }{\mathrm{GeV}}^{2}$ and $0.08l{m}_{{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}}^{2}l0.66\text{ }\text{ }{\mathrm{GeV}}^{2}$, ${\mathcal{A}}_{\mathcal{C}\mathcal{P}}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}_{0}^{*}(1430){\ensuremath{\pi}}^{\ensuremath{-}})=0.061\ifmmode\pm\else\textpm\fi{}0.032$, $\mathcal{B}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}_{0}^{*}(1430){\ensuremath{\pi}}^{\ensuremath{-}})=({39}_{\ensuremath{-}5}^{+6})\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ and $\mathcal{B}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\sigma}(600){\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\rightarrow}\phantom{\rule{0ex}{0ex}}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})l4.1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$, we get the end-point divergence parameters in our model, ${\ensuremath{\phi}}_{S}\ensuremath{\in}[1.77,2.25]$ and ${\ensuremath{\rho}}_{S}\ensuremath{\in}[2.39,4.02]$. Using these results for ${\ensuremath{\rho}}_{S}$ and ${\ensuremath{\phi}}_{S}$, we predict that the $CP$ asymmetry parameter ${\mathcal{A}}_{\mathcal{C}\mathcal{P}}\ensuremath{\in}[\ensuremath{-}0.34,\ensuremath{-}0.11]$ and the branching fraction $\mathcal{B}\ensuremath{\in}[6.53,17.52]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ for the ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}\ensuremath{\sigma}(600)$ decay. In addition, we also analyze contributions to the localized $CP$ asymmetry ${\mathcal{A}}_{\mathcal{C}\mathcal{P}}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})$ from $[\ensuremath{\pi}\ensuremath{\pi}]$, $[K\ensuremath{\pi}]$ channel resonances and nonresonance individually, which are found to be ${\mathcal{A}}_{\mathcal{C}\mathcal{P}}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}[{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}]\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})=0.509\ifmmode\pm\else\textpm\fi{}0.042$, ${\mathcal{A}}_{\mathcal{C}\mathcal{P}}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}[{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}]\ensuremath{\pi}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})=0.174\ifmmode\pm\else\textpm\fi{}0.025$ and ${{\mathcal{A}}_{\mathcal{C}\mathcal{P}}}^{\mathrm{NR}}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})=0.061\ifmmode\pm\else\textpm\fi{}0.0042$, respectively. Comparing these results, we can see that the localized $CP$ asymmetry in the ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decay is mainly induced by the $[\ensuremath{\pi}\ensuremath{\pi}]$ channel resonances while contributions from the $[K\ensuremath{\pi}]$ channel resonances and nonresonance are both very small.

Within the quasi-two-body decay model, we study the localized CP violation and branching fraction of the four-body decay when the and pair invariant masses are and , with the pairs being dominated by the , , , and , and , , and resonances, respectively. When dealing with the dynamical functions of these resonances, , , and are modeled with the Bugg model, Gounaris-Sakurai function, Flatté formalism and LASS lineshape, respectively, while the others are described by the relativistic Breit-Wigner function. Adopting the end point divergence parameters and , our predicted results are and , based on the hypothetical structures for the scalar mesons in the QCD factorization approach. Meanwhile, we calculate the CP violating asymmetries and branching fractions of the two-body decays and all the individual four-body decays , respectively. Our theoretical results for the two-body decays , , , , and are consistent with the available experimental data, with the remaining predictions await testing in future high precision experiments.

In recent years, with the development of simulations about supernova explosion, we have a better understanding about the density profiles and the shock waves in supernovae than before. There might be a reverse shock wave, another sudden change of density except the forward shock wave, or even no shock wave, emerging in the supernova. Instead of using the expression of the crossing probability at the high resonance, P-H, we have studied the matter effects on neutrino oscillations in different supernova models. In detail, we have calculated the survival probability of v(e) (P-s) and the conversion probability of v(x) (P-c) in the Schrodinger equation within a simplified two-flavor framework for a certain case, in which the neutrino transfers through the supernova matter from an initial flavor eigenstate located at the core of the supernova. Our calculations was based on the data of density in three different supernova models obtained from simulations. In our work, we do not steepen the density gradient around the border of the shock wave, which differs to what was done in most of the other simulations. It is found that the mass and the density distribution of the supernova do make a difference on the behavior of P-s and P-c. With the results of P-s and P-c, we can estimate the number of v(e) (and v(x)) remained in the beam after they go through the matter in the supernova.

In this work, we study the localized violation and the branching fraction of the four-body decay by employing a quasi-two-body QCD factorization approach. Considering the interference of and channels, we predict and , respectively, which shows that the interference mechanism of these two channels can induce the localized violation to this four-body decay. Meanwhile, within the two quark model framework for the scalar mesons and , we calculate the direct CP violations and branching fractions of the and decays, respectively. The corresponding results are , , and , indicating that the violations of these two-body decays are both positive and the branching fractions quite different. These studies provide a new way to investigate the aforementioned four-body decay and can be helpful in clarifying the configuration of the structure of the light scalar meson.

We study the rare decays in the Bethe-Salpeter equation approach. We find that the branching ratio is in our model. This result agrees with the experimental data well. In the same parametric region, we find that the branching ratio is .

We study the residues of ΛQ-type baryons (ΛQ and ΞQA) (Q=b,c) and ΣQ-type baryons (ΣQ(*), ΞQS(*) and ΩQ(*)) in the quark-diquark model within the Bethe-Salpeter (BS) formalism. These residues can be used, e.g., in the calculations of the amplitudes in the scattering processes. After constructing the baryonic currents in the BS formalism, we derive the relations between the BS wave functions and the residues for these baryons. The BS equations are solved numerically with the kernel including the scalar confinement and the one-gluon-exchange terms and with the covariant instantaneous approximation being employed in the calculations. Finally, we obtain the numerical values of the residues 0.103 GeV∼0.224 GeV for ΛQ, 0.143 GeV∼0.215 GeV for ΞQA, 0.262 GeV∼0.361 GeV for ΣQ(*), 0.313 GeV∼0.460 GeV for ΞQS(*) and 0.473 GeV∼0.571 GeV for ΩQ(*) in the ranges of the parameters in our model.

We study the Λc(2595)+ and Σc(2800)0 states as the ND bound systems in the Bethe-Salpeter formalism in the ladder and instantaneous approximations. With the kernel induced by ρ, ω and σ exchanges, we solve the Bethe-Salpeter equations for the ND bound systems numerically and find that the bound states may exist. We assume that the observed states Λc(2595)+ and Σc(2800)0 are S-wave ND molecular bound states and calculate the decay widths of Λc(2595)+→Σc0π+ and Σc(2800)0→Λc+π-.

We study the $S$-wave $D\Xi$ bound state in the Bethe-Salpeter formalism in the ladder and instantaneous approximations. With the kernel generated by the hadronic effective Lagrangian, two open-charmed bound states, which quantum numbers are $I=0$, $J^P=(\frac{1}{2})^-$ and $I=1$, $J^P=(\frac{1}{2})^-$, respectively, are predicted as new candidates of hadronic pentaquark molecules in our formalism. If existing, they could contribute to the broad 3188 eV structure near the five new narrow $\Omega_c$ states observed recently by the LHCb Collaboration.

We discuss the possibility that the X(3872) can be a DD¯* molecular bound state in the Bethe-Salpeter equation approach in the ladder and instantaneous approximations. We show that the DD¯* bound state with quantum numbers JPC=1++ exists. We also calculate the decay width of X(3872)→γJ/ψ channel and compare our result with those from previous calculations.

The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purpose underground liquid scintillator detector, was proposed with the determination of the neutrino mass hierarchy as a primary physics goal. It is also capable of observing neutrinos from terrestrial and extra-terrestrial sources, including supernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos, atmospheric neutrinos, solar neutrinos, as well as exotic searches such as nucleon decays, dark matter, sterile neutrinos, etc. We present the physics motivations and the anticipated performance of the JUNO detector for various proposed measurements. By detecting reactor antineutrinos from two power plants at 53-km distance, JUNO will determine the neutrino mass hierarchy at a 3-4 sigma significance with six years of running. The measurement of antineutrino spectrum will also lead to the precise determination of three out of the six oscillation parameters to an accuracy of better than 1\%. Neutrino burst from a typical core-collapse supernova at 10 kpc would lead to ~5000 inverse-beta-decay events and ~2000 all-flavor neutrino-proton elastic scattering events in JUNO. Detection of DSNB would provide valuable information on the cosmic star-formation rate and the average core-collapsed neutrino energy spectrum. Geo-neutrinos can be detected in JUNO with a rate of ~400 events per year, significantly improving the statistics of existing geoneutrino samples. The JUNO detector is sensitive to several exotic searches, e.g. proton decay via the $p\to K^++\bar\nu$ decay channel. The JUNO detector will provide a unique facility to address many outstanding crucial questions in particle and astrophysics. It holds the great potential for further advancing our quest to understanding the fundamental properties of neutrinos, one of the building blocks of our Universe., Comment: Version submitted to Journal of Physics G, with minor typo corrections. 222 Pages, 147 figures

In the QCD factorization (QCDF) approach we study the direct CP violation inB-0→ρ0(ω)ρ0(ω)→π+π-π+π-via theρ-ωmixing mechanism. We find that the CP violation can be enhanced by doubleρ-ωmixing when the masses of theπ+π-pairs are in the vicinity of theωresonance, and the maximum CP violation can reach 28%. We also compare the results from the naive factorization and the QCD factorization.

The heavy baryon ${\mathrm{\ensuremath{\Lambda}}}_{b}$ is regarded as composed of a heavy quark and a scalar diquark which has good spin and isospin quantum numbers. In this picture, we calculate the electromagnetic form factors of ${\mathrm{\ensuremath{\Lambda}}}_{b}$ in the Bethe-Salpeter equation approach in the spacelike region. We find that the shapes of the electromagnetic form factors of ${\mathrm{\ensuremath{\Lambda}}}_{b}$ are similar to those of $\mathrm{\ensuremath{\Lambda}}$, with a peak at $\ensuremath{\omega}=1$ (for the magnetic form factor) and $\ensuremath{\omega}\ensuremath{\simeq}1.1$ (for the electric form factor)($\ensuremath{\omega}={v}^{\ensuremath{'}}\ifmmode\cdot\else\textperiodcentered\fi{}v$ is the velocity transfer between the initial state (with velocity $v$) and the final state (with velocity ${v}^{\ensuremath{'}}$) of ${\mathrm{\ensuremath{\Lambda}}}_{b}$), but the amplitudes are much smaller than those of $\mathrm{\ensuremath{\Lambda}}$.

In this work, within the QCD factorization approach, we study the localized integrated CP violation in the B−→π−π+π− decay and the branching fraction of the B−→σπ− decay. Both the resonance and nonresonance contributions are included when we study the localized CP asymmetry in the B−→π−π+π− decay. The resonance contributions from the scalar σ(600) and vector ρ0(770) mesons are included. For the σ(600) meson, we apply both the Breit-Wigner and Bugg models to deal with its propagator, and obtain B(B−→σ(600)π−)15 GeV2 and mπ+π−low2

Recently, some singly bottom baryons have been established experimentally, but none of doubly or triply bottom baryons has been observed. Under the Regge phenomenology, the mass of a ground state unobserved doubly or triply bottom baryon is expressed as a function of masses of the well established light baryons and singly bottom baryons. Then, the values of Regge slopes and Regge intercepts for baryons containing one, two, or three bottom quarks are calculated. After that, masses of the orbitally excited singly, doubly, and triply bottom baryons are estimated. Our predictions may be useful for the discovery of these baryons and the $J^P$ assignment of them., 20 pages, 8 tables

We study the localized direct $CP$ violation in the hadronic decays ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{\ensuremath{\rho}}^{0}(\ensuremath{\omega}){\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$, including the effect caused by an interesting mechanism involving the charge symmetry violating mixing between ${\ensuremath{\rho}}^{0}$ and $\ensuremath{\omega}$ in the QCD factorization approach. We find that $\ensuremath{\rho}\text{\ensuremath{-}}\ensuremath{\omega}$ mixing makes the localized integrated $CP$ asymmetry move toward the negative direction when the low invariant mass of ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ [$m({\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{)}_{\mathrm{low}}$] is near ${\ensuremath{\rho}}^{0}(770)$. The localized integrated direct $CP$ violation obtained in the QCD factorization approach varies from $\ensuremath{-}0.0724$ to $\ensuremath{-}0.0389$ in the ranges of parameters when $0.750lm({\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{)}_{\mathrm{low}}l0.800\text{ }\text{ }\mathrm{GeV}$. This result, especially the sign, agrees with the experimental data. We also calculate the localized integrated direct $CP$ violating asymmetries in the QCD factorization approach in the regions $0.470lm({\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{)}_{\mathrm{low}}l0.770\text{ }\text{ }\mathrm{GeV}$ and $0.770lm({\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{)}_{\mathrm{low}}l0.920\text{ }\text{ }\mathrm{GeV}$. We find that these results agree with the experimental data and are more accurate than the results obtained through the naive factorization approach. It is more clear that $\ensuremath{\rho}\text{\ensuremath{-}}\ensuremath{\omega}$ mixing contributes to the sign change in these two regions.

In the framework of factorization, we study direct CP violation in the decays of B(s) → J/ψP(V) (P(V) refer to the pseudoscalar (vector) meson). The CP violation depends strongly on Cabibbo-Kobayashi-Maskawa (CKM) matrix elements and the effective parameter, Nc. The recent experimental data for the branching ratios of B(s) → J/ψP(V) are accurate enough and we can give a strong constraint on the range of Nc. We find that the CP violating asymmetry is consistent with the available experiment values for the b → d transition, and a little smaller than the b → s transition. We also predict the CP violation of other decay channels for B(s) → J/ψP(V). We expect our results can give valuable guidance for experiments.

We analyze the radiative leptonic Bc decay Bc− → τ−νγ in the Standard Model and the two-Higgs-doublet model using the non-relativistic constituent quark model. The results confirm that this channel is experimentally promising in view of the large number of Bc mesons which are expected to be produced at future hadron facilities. We also find that this decay is sensitive to the parameters of the two-Higgs-doublet model, and it can be tested in future experiments.

We studied the electromagnetic form factors (EMFFs) of Λ c and the contributions of the quark and diquark currents to the EMFFs of Λ c in the space-like region in the Bethe–Salpeter equation approach with instantaneous approximation. In this picture, baryon Λ c can be regarded as a two-body c(ud) system. We found that for different values of parameters the contribution of quark and diquark currents to the EMFFs of Λ c is very different, while their total contribution to the EMFFs of Λ c is similar. The EMFFs of Λ c are similar to those of other baryons (proton, Ξ−, and Σ+) with a peak at ω = 1, where ω = v′ · v is the velocity transfer between the initial state (with velocity v) and the final state (with velocity v′) of Λ c .

In the framework of the constituent quark model, the possible S-wave heavy dibaryon states with the c flavor are investigated. The factors which are responsible for the binding behavior of the dibaryon system are analyzed. It is shown that both the symmetry character of the system and the energy of interactions between interacting quarks are important for the binding behavior of the two-baryon system with the heavy flavor. As a result, seven possible candidates of heavy dibaryons with c flavor are predicted.

We study the localized direct CP violation in the hadronic decays $B^\pm\rightarrow \rho^0 (\omega)\pi^\pm\rightarrow\pi^+ \pi^-\pi^\pm$, including the effect caused by an interesting mechanism involving the charge symmetry violating mixing between $\rho^0$ and $\omega$. We calculate the localized integrated direct CP violation when the low invariant mass of $\pi^+\pi^-$ [$m(\pi^+\pi^-)_{low}$] is near $\rho^0(770)$. For five models of form factors investigated, we find that the localized integrated direct CP violation varies from -0.0170 to -0.0860 in the ranges of parameters in our model when $0.750

Until now, the first reported doubly charmed baryon $\Xi_{cc}^{+}(3520)$ is still a puzzle. It was discovered and confirmed by SELEX collaboration, but not confirmed by LHCb, BABAR, BELLE, FOCUS, or any other collaboration. In the present paper, by employing Regge phenomenology, we first express the mass of the ground state ($L$=0) doubly charmed baryon $\Omega_{cc}^{*+}$ as a function of masses of the well established light baryons and singly charmed baryons. Inserting the recent experimental data, the mass of $\Omega_{cc}^{*+}$ is given to be 3809$\pm$36 MeV, which is independent of any unobservable parameters. Then, with the quadratic mass relations, we calculate the masses of the ground state triply charmed baryon $\Omega_{ccc}^{++}$ and doubly charmed baryons $\Xi_{cc}^{(*)++}$, $\Xi_{cc}^{(*)+}$, and $\Omega_{cc}^{+}$ (the mass of $\Xi_{cc}^{+}$ is determined as 3520$^{+41}_{-40}$ MeV, which agrees with the mass of $\Xi_{cc}^{+}(3520)$). The isospin splitting $M_{\Xi_{cc}^{++}} - M_{\Xi_{cc}^{+}} = 0.4 \pm 0.3$ MeV. After that, masses of the orbitally excited ($L$=1,2,3) doubly and triply charmed baryons are estimated. The results are reasonable comparing with those extracted in many other approaches. We suggest more efforts to study doubly and triply charmed baryons both theoretically and experimentally, not only for the abundance of baryon spectra, but also for numerically examining whether the linear mass relations or the quadratic mass relations are realized in nature. Our predictions are useful for the discovery of unobserved doubly and triply charmed baryon states and the $J^P$ assignment of these states., Comment: 15 pages, 5 tables, version published in PRD

With the diquark structure of Lambda_c, we investigate the branching ratios of Lambda_c -> n pi^+ and p pi^0. The results show that without considering the final state interaction (FSI), the branching ration of Lambda_c -> p pi^+ is only of order 10^{-6} whereas taking into account the FSI effects, this ratio could reach 10^{-4} and is at the same order as Lambda_c -> n pi^0. Concrete values depend on phenomenological parameters adopted in the calculations. These branching ratios can be measured in the experiments to come., 19 pages, 1 figure

Up to now, the excited charmed and bottom baryon states are still not well studied both experimentally and theoretically. In the present paper, we predict the mass of $\Omega_b^*$, the only $L = 0$ baryon state which has not been observed, to be 6069.2 MeV. The spectra of charmed and bottom baryons with the orbital angular momentum $L = 1$ are studied in two popular constituent quark models, the Goldstone boson exchange (GBE) and the one gluon exchange (OGE) hyperfine interaction models, respectively. Inserting the latest experimental data from the "Review of Particle Physics", we find that in the GBE model, there exist some multiplets ($\Sigma_{c(b)}$, $\Xi'_{c(b)}$ and $\Omega_{c(b)}$) which total spins of three quarks in their lowest energy states are 3/2, but in the OGE model there is no such phenomenon. This is the most important difference between the GBE and OGE models. These results can be tested in the near future. We suggest more efforts to study the excited charmed and bottom baryons both theoretically and experimentally, not only for the abundance of baryon spectra, but also for determining which hyperfine interaction model is realized in nature.

We study the direct CP violation in the $\tau^\pm\rightarrow K^\pm \rho^0 (\omega)\nu_\tau \rightarrow K^\pm \pi^+\pi^-\nu_\tau$ decay process in the Standard Model. An interesting mechanism involving the charge symmetry violating mixing between $\rho^0$ and $\omega$ is applied to enlarge the CP asymmetry. With this mechanism, the maximum differential and localized integrated CP asymmetries can reach $-(5.6^{+2.9}_{-1.7})\times10^{-12}$ and $6.3^{+2.4}_{-3.3}\times 10^{-11}$, respectively, which still leave plenty room for CP-violating New Physics to be discovered through this process.

In the framework of QCD factorization we study the direct $CP$ violation in $B\ensuremath{\rightarrow}{\ensuremath{\rho}}^{0}(\ensuremath{\omega})V\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}V$ ($V$ is a vector meson) via the $\ensuremath{\rho}\ensuremath{-}\ensuremath{\omega}$ mixing mechanism. We find that the $CP$ violation can be enhanced by $\ensuremath{\rho}\ensuremath{-}\ensuremath{\omega}$ mixing when the masses of the ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ pairs are in the vicinity of the $\ensuremath{\omega}$ resonance. For the decay channel of ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\rho}}^{0}(\ensuremath{\omega}){\ensuremath{\rho}}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\rho}}^{\ensuremath{-}}$, the maximum $CP$ violation can reach 18%. We also discuss the possibility to observe the $CP$ violation at the LHC.

A measurement of the energy dependence of antineutrino disappearance at the Daya Bay Reactor Neutrino Experiment is reported. Electron antineutrinos ($\overline{\nu}_{e}$) from six $2.9$ GW$_{\rm th}$ reactors were detected with six detectors deployed in two near (effective baselines 512 m and 561 m) and one far (1579 m) underground experimental halls. Using 217 days of data, 41589 (203809 and 92912) antineutrino candidates were detected in the far hall (near halls). An improved measurement of the oscillation amplitude $\sin^{2}2\theta_{13} = 0.090^{+0.008}_{-0.009} $ and the first direct measurement of the $\overline{\nu}_{e}$ mass-squared difference $|\Delta m^{2}_{ee}|= (2.59_{-0.20}^{+0.19}) \times 10^{-3}\ {\rm eV}^2 $ is obtained using the observed $\overline{\nu}_{e}$ rates and energy spectra in a three-neutrino framework. This value of $|\Delta m^{2}_{ee}|$ is consistent with $|\Delta m^{2}_{\mu\mu}|$ measured by muon neutrino disappearance, supporting the three-flavor oscillation model., Comment: As accepted for publication by Phys. Rev. Lett. including ancillary table

The difference of tau (B) and tau (Lambdab) indicates the role of the light flavors. We calculate the lifetimes of B-meson and hb based on the weak effective Hamiltonian while assuming the heavy baryon is constructed by a heavy b-quark and a diquark containing two light quarks. In this scenario, we use the information of the measured ratio tau (Lambdab)/tau (B) as input to predict rates of the inclusive weak decays of Sigma (()(b)*()) and Xi (()(b)*()) into non-bottom final states. We find that these rates of Sigma (()(b)*()) and Xi (()(b)*()) are much larger than those of B-mesons and Lambda (b). We also give the predictions for the lifetimes of Omega (b) and Omega (b)*. Phenomenological implication of our result is discussed.

Recently, the large $CP$ asymmetries in ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decays were found by the LHCb Collaboration to localize in the region ${m}_{{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}}^{2}l0.4\text{ }\text{ }{\mathrm{GeV}}^{2}$. We find such large localized $CP$ asymmetries may be due to the interference between a light scalar and ${\ensuremath{\rho}}^{0}(770)$ intermediate resonances. Consequently, we argue that the distribution of $CP$ asymmetries in the Dalitz plots of three-body $B$ decays could be very helpful for identifying the presence of the scalar resonance.

Supernova (SN) neutrinos detected on the Earth are subject to the shock wave effects, the Mikheyev-Smirnov-Wolfenstein (MSW) effects, the neutrino collective effects and the Earth matter effects. Considering the recent experimental result about the large mixing angle $\theta_{13}$ ($\backsimeq8.8^{\circ}$) provided by the Daya Bay Collaboration and applying the available knowledge for the neutrino conversion probability in the high resonance of SN, $P_{H}$, which is in the form of hypergeometric function in the case of large $\theta_{13}$, we deduce the expression of $P_{H}$ taking into account the shock wave effects. It is found that $P_{H}$ is not zero in a certain range of time due to the shock wave effects. After considering all the four physical effects and scanning relevant parameters, we calculate the event numbers of SN neutrinos detected at the Daya Bay experiment. From the numerical results, it is found that the behaviors of neutrino event numbers detected on the Earth depend on the neutrino mass hierarchy and neutrino spectrum parameters including the temperature $T_{\alpha}$, the dimensionless pinching parameter $\eta_{\alpha}$ or $\beta_{\alpha}$ (where $\alpha$ refers to neutrino flavor), the average energy $< E_{\alpha}>$, and the SN neutrino luminosities $L_{\alpha}$. We also compare the results of two parametrization methods for the neutrino energy distributions and give the ranges of SN neutrino event numbers that will be detected at the Daya Bay experiment., Comment: 24 pages, 9 figures, submitted to Phys. Rev. D

We introduce the vector meson contributions in heavy-light chiral perturbation theory (HLCPT) and construct the Lagrangian and current to the order 1/mQ. With this, to the order (Λcsb is the chiral symmetry breaking scale) we calculate corrections to fD and fB arising from coupled-channel effects to the orders 1/mc, and 1/mb. At the tree level in HLCPT, using the relativistic Bethe–Salpeter (BS) equation with the kernel containing a confinement term and a gluon exchange term in a covariant generalization of the coulomb gauge we calculate and when mQ → ∞ as well as the 1/mQ corrections. HLCPT and the heavy quark effective theory (HQET) are matched at the scale Λcsb. Adding the perturbative and nonperturbative contributions we give the values for fD and fB, respectively. It is found that our result is in agreement with the relation fD = fB from lattice calculations.

After considering the supernova shock effects, the Mikheyev-Smirnov-Wolfenstein effects, the neutrino collective effects, and the Earth matter effects, the detection of supernova neutrinos at China Spallation Neutron Sources is studied and the event numbers of different flavor supernova neutrinos observed through various reaction channels are calculated with the neutrino energy spectra described by the Fermi-Dirac distribution and "beta fit" distribution respectively. Furthermore, the numerical calculation method of supernova neutrino detection on the Earth is applied to some other spallation neutron sources, and the total event numbers of supernova neutrinos observed through different reactions channels are given., Comment: 7 pages, 2 figures

The semileptonic decay [ital T][sub [ital b]][r arrow][ital T][sub [ital c]][pi][ital l][bar [nu]] is considered in the framework of heavy quark effective theory to the order 1/[ital m][sub [ital c]] and 1/[ital m][sub [ital b]]. This process is described by a set of six independent universal form factors. In the soft pion limit, the soft-pion theorem is used to derive normalization conditions for these form factors.

In the heavy quark limit, we establish the Bethe-Salpeter equation for the possible molecular state containing one heavy meson D and one light meson K. With the kernel induced by one-particle-exchange diagrams, we solve the Bethe-Salpeter equation numerically in the ladder and covariant instantaneous approximations and find that the DK bound state may exist. Assuming the observed state D*(s0)(2317)(+) is an S-wave DK molecular bound state we calculate the strong decay width of D*(s0)(2317)(+). Our prediction for the decay width Gamma(D*(s0)(2317)(+) -> D-s(+) pi(0)) is consistent with the previous investigations and the current experimental data.

A consistent equation for the quark condensate in the chiral limit provides a determination of the renormalization-group-invariant quark condensate. A critical point at which the strong coupling constant is big enough for chiral symmetry breaking to take place is found. They are analyzed at the one- and two-loop levels respectively. An intuitive picture of the condensation above the critical coupling constant is discussed.

The suppressed Λ b → Σ c (∗) decay form factors are analyzed using the heavy quark effective theory (HQET) to second order power corrections. We find that to order 1 m c and 1 m b , four form factors are needed to describe these decays while to order 1 m c 2 , 1 m b 2 and 1 m c m a b , 26 more form factors are introduced. Our result for the 1 m c contribution is at variance with the previous result. It is shown that at the zero-recoil point 1 m c 2 and 1 m c m b terms are the leading ones contributing to Λb → Σc and Λ b → Σ ∗ c respectively. We also give a rough estimate for the decay width Λb → Σclν.

We propose a kind of electromagnetic (EM) diode based on a two-dimensional nonreciprocal gyrotropic photonic crystal. This periodic microstructure has separately broken symmetries in both parity (P) and time-reversal (T) but obeys parity-time (PT) symmetry. This kind of diode could support bulk one-way propagating modes either for group velocity or phase velocity with various types of negative and positive refraction. This symmetry-broken system could be a platform to realize abnormal photoelectronic devices, and it may be analogous to an electron counterpart with one-way features.

We prove that in the limit ${m}_{b},{m}_{c}\ensuremath{\rightarrow}\ensuremath{\infty}$, with ${m}_{c}/{m}_{b}$ fixed, factorization holds at order ${\ensuremath{\alpha}}_{s}$ for the decay ${\ensuremath{\Lambda}}_{b}^{0}\ensuremath{\rightarrow}{\ensuremath{\Lambda}}_{c}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$. This proof is done in the infinite-momentum frame in which the momenta of $\ensuremath{\pi}$, ${\ensuremath{\Lambda}}_{c}$, and ${\ensuremath{\Lambda}}_{b}$ go to infinity. Our result is renormalization-scale- and scheme-independent at $\mathcal{O}({\ensuremath{\alpha}}_{s})$. This is the same as the QCD factorization for $B\ensuremath{\rightarrow}D\ensuremath{\pi}$.