The first synthetic study on PbBiO 2 I/PbO nanocomposite preparation using a controlled hydrother... more The first synthetic study on PbBiO 2 I/PbO nanocomposite preparation using a controlled hydrothermal method is reported. The morphologies and composition of the samples are controlled by adjusting some parameters, including reaction pH, Pb/Bi molar ratio, and temperature. All the samples are characterized by XRD, TEM, XPS, SEM-EDS, PL, BET, EPR, and UV-vis-DRS. The photodegradation activities are evaluated against the de-colorization of crystal violet (CV) and 2-hydroxybenzoic acid (2-HBA) in aqueous solution under visible light illumination. In particular, the catalytic performance illustrates the best reaction rate constant 1.159 × 10 −1 h −1 once PbBiO 2 I/PbO is used as the photocatalyst for the degradation of CV; which is 3 and 20 times higher than the reaction rate constants of PbBiO 2 I and PbO being the photocatalysts, respectively. This study reveals that PbBiO 2 I/PbO can be used for repressing the recombination of photo-generated electron-hole pairs and contribute to the enhanced photocatalytic activity of semiconductors in the visible-light-driven catalysis. The possible photocatalytic degradation mechanism is studied by using different active species through EPR and adding suitable scavengers. When being irradiated, two major active species, O 2 − and 1 O 2 , and a minor active species, h + , can be produced for the CV degradation.
Journal of Molecular Catalysis A-chemical, Jun 1, 2016
This is the first report that PbBiO 2 Br/BiOBr is synthesized by a template-free hydrothermal met... more This is the first report that PbBiO 2 Br/BiOBr is synthesized by a template-free hydrothermal method. The composition and morphologies of the samples could be controlled by adjusting some growth parameters, including reaction pH, Pb/Bi molar ratio, and temperature. All the samples are characterized by XRD, TEM, XPS, SEM-EDS, FT-IR, BET, EPR, and UV-vis-DRS. The PbBiO 2 Br/BiOBr photocatalysts exhibit enhanced photocatalytic activities on the degradation of crystal violet (CV) under visible-light irradiation. In particular, the catalytic performance illustrates the best reaction rate constant 1.257 × 10 −1 h −1 once PbBiO 2 Br/BiOBr is used as the photocatalyst; which is 3 and 2 times higher than the reaction rate constant of PbBiO 2 Br and BiOBr being the photocatalysts, respectively. This study reveals that PbBiO 2 Br/BiOBr can be used to suppress the recombination of photoinduced electron-hole pairs and contribute to the enhanced photocatalytic efficiency of semiconductors in the visible-light-driven catalysis. The possible photodegradation mechanism is studied by examining different active species through EPR and adding appropriate scavengers. The results demonstrate that the reactive O 2 − plays the major and OH the minor roles in the CV degradation.
Journal of Colloid and Interface Science, Sep 1, 2018
This paper presents an unprecedented systematic synthetic study of a controlled hydrothermal meth... more This paper presents an unprecedented systematic synthetic study of a controlled hydrothermal method for the preparation of bismuth oxychloride/bismuth oxybromide/bismuth oxyiodide ternary composites (BiO x Cl y /BiO m Br n /BiO p I q). The pH, temperature, and KCl:KBr:KI molar ratio for the reactions were adjusted to control the compositions and morphologies of BiO x Cl y /BiO m Br n /BiO p I q composites. Scanning electron microscopy-energy dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, ultraviolet-visible diffuse reflectance spectroscopy, Brunauer-Emmett-Teller specific surface areas, photoluminescence spectroscopy, and X-ray photoelectron spectroscopy, and electron paramagnetic resonance spectroscopy were applied to the products. The photocatalytic activities of dispersions were examined by monitoring the 2-hydroxybenzoic acid (HBA) and crystal violet concentrations. Various scavengers 2 demonstrated quenching effects. O 2 •− was crucial to HBA degradation, whereas h + and • OH played minor roles in HBA degradation. This text hypothesizes possible photodegradation mechanisms. Keywords: Photocatalysis, BiO x Cl y /BiO m Br n /BiO p I q , composites, 2-hydroxybenzoic acid, crystal violet
The nonleptonic heavy meson decays B → D (*) π(ρ), J/ψK (*) and D → K (*) π are studied based on ... more The nonleptonic heavy meson decays B → D (*) π(ρ), J/ψK (*) and D → K (*) π are studied based on the three-scale perturbative QCD factorization theorem developed recently. In this formalism the Bauer-Stech-Wirbel parameters a 1 and a 2 are treated as the Wilson coefficients, whose evolution from the W boson mass down to the characteristic scale of the decay processes is determined by effective field theory. The evolution from the characteristic scale to a lower hadronic scale is formulated by the Sudakov resummation. The scale-setting ambiguity, which exists in the conventional approach to nonleptonic heavy meson decays, is moderated. Nonfactorizable and nonspectator contributions are taken into account as part of the hard decay subamplitudes. Our formalism is applicable to both bottom and charm decays, and predictions, including those for the ratios R and R L associated with the B → J/ψK (*) decays, are consistent with experimental data.
In this work, we propose a model by combining the parametrization method and the QCD factorizatio... more In this work, we propose a model by combining the parametrization method and the QCD factorization to study the B → πK puzzle. The parametrization for the B → πK amplitudes introduces twelve parameters, the weak angle γ and the other eleven hadronic parameters. These hadronic parameters are assumed to be perturbative and can be calculated by the QCD factorization (QCDF). The calculational accuracy of the QCDF is improved by including the twist-3 three parton tree and one loop corrections. Three additional nonperturbative strong phases from the gluonic penguin, color suppressed, and color favored tree diagrams are required to account for the direct CP asymmetries. The weak angle, three nonperturbative strong phases, and four scale variables are assumed as fitting parameters. Four scale variables represent the factorization scales for the decays, each decay mode with one scale. These eight parameters are determined by a least squares fit to the eight measurements for B → πK decays, four branching ratios and four direct CP asymmetries. The fit shows that the hadronic parameters need to be process-dependent. A large negative relative phase associated with the internal up quark gluonic penguin diagram is observed. The weak angle γ is found to be 72.1 ± 5.8 degree, being consistent with the world averaged value, 72.1 ± 5.8 degree. By a least squares fit to the mixing induced asymmetry S(π 0 KS) = 0.58 ± 0.06, the weak angle β is determined to be 22.9 ± 2.1 degree, which is in a well agreement with the world averaged value, 22.5 ± 4.4 ± 0.6 degree. The model predicts the ratio C /T (color suppressed/color favored) to be 0.59 ± 0.08. The above evidences indicate that the model can solve the B → πK puzzle consistently. The model is used to examine the quadrangle relation of the isospin symmetry assumed for the B → πK system. The ratio of the two sides of the quadrangle relation is calculated to be (0.87±0.15) exp(−i22 •), which signals the isospin symmetry breaking at 6σ. The process-dependent hadronic parameters break the isospin symmetry "dynamically". The application of our method to other decay processes is straightforward.
We present a first perturbative evaluation on the next-to-leading-order (NLO) $O(1/Q^4)$ power co... more We present a first perturbative evaluation on the next-to-leading-order (NLO) $O(1/Q^4)$ power corrections of the photon-pion transition form factor $F_{\pi\gamma}(Q^2)$. There involve four next-to-leading-twist (NLT) distribution amplitudes (DAs). A power expansion, which is compatible with QCD factorization, is built and employed for calculations.
The polarization of Λ b baryon has been measured in ALEPH, OPAL and DELPHI experiments. A signifi... more The polarization of Λ b baryon has been measured in ALEPH, OPAL and DELPHI experiments. A significant loss on the transfer of the b quark polarization to the Λ b baryon polarization has been noticed. This implies that the hadronization effects can not be neglected. Therefore, we may make use of the polarization measurements to look for suitable model for the Λ b distribution function. To investigate nonperturbative effects implied in the Λ b polarization, we construct four models based on a perturbative QCD factorization formula. The models are the quark model (QM), the modified quark model (MQM), the parton model (PM), and the modified parton model (MPM). The modified models mean the models having transverse degrees of freedom and the associated soft radiative corrections having been resummed. The quark and parton models can not describe all experiments in the same time. On the other hand, the modified models can have the power to explain all data in the same formalism.
We propose a perturbative evaluation for the next-toleading-order (NLO) O(1/Q 4) power correction... more We propose a perturbative evaluation for the next-toleading-order (NLO) O(1/Q 4) power correction to the photon pion transition form factor Fπγ (Q 2). The effects of the NLO power correction are analyzed.
An ecofriendly and cheap photocatalyst is crucial for realizing practical photocatalysis applicat... more An ecofriendly and cheap photocatalyst is crucial for realizing practical photocatalysis applications. Many inorganic materials have modular structures in which individual units are responsible for different functions. [Bi 2 O 2 ] 2+ slabs with an α-PbO-type structure and simple halide layers are effective spacers in some layered functional materials. Previous reports have mainly discussed electronic reasons for the different photocatalytic activities of layered PbBiO 2 X-type materials (X = Cl, Br, I). To the best of our knowledge, nanocomposite semiconductors consisting of PbBiO 2 I/g-C 3 N 4 have not been reported in the literature. In this study, PbBiO 2 X/g-C 3 N 4 composites were isolated and characterized by FE-SEM-EDS, XRD, HR-XPS, TEM, PL, BET, FT-IR, and UV-vis-DRS. By degrading crystal violet (CV) and 2-hydroxybenzoic acid (HBA) in an aqueous solution under visible-light irradiation, the photocatalytic activities of PbBiO 2 I/g-C 3 N 4 are discussed further. In particular, the catalytic performance illustrates the best reaction rate constants of 0.3259 h −1 using the PbBiO 2 I/g-C 3 N 4 composite as the photocatalysts; these are 13.7 and 9.1 times higher than those of PbBiO 2 I and g-C 3 N 4 , respectively. The quenching effects of different scavenger results demonstrate that reactive O 2 %− plays the major role and % OH, h + , and 1 O 2 play the minor role in CV degradation.
In many years ago, Isgur and Llewellyn Smith addressed that PQCD is inapplicable to exclusive pro... more In many years ago, Isgur and Llewellyn Smith addressed that PQCD is inapplicable to exclusive processes [1,2], such as the pion form factor. The main problem is that the asymptotic of PQCD is only about one fourth of the experimental value [3-5]. We reexamine this PQCD deep problem. By including NLO power corrections to the pion form factor, we may arrive at a perturbative explanation for the data. The key realization is that we need to interprete that the strong interaction coupling constant involved in the PQCD result should be taken as an effective coupling constant under nonperturbative QCD vaccum. This implies that one can equally identify the relevant scale for the effective coupling constant as the factorization scale about 1 GeV. We also find that the average momentum fraction variable locates about 0.5, which is in favor of the asymptotic pion wave function. By employing photon-pion form factor with NLO power corrections to factorize out the nonperturbative effects involved in the effective coupling constant, we can extract an effective running coupling constant, which represents an effective coupling involving in the hard scattering subprocesses. The difference between the effective running coupling constant and the usual perturbative running coupling constant (Λ QCD = 0.3 GeV) is very small for Q 2 > 1 GeV 2. The effective running coupling constant αs/π is smaller than 0.2 for Q 2 > 1 GeV 2. This directly showes that PQCD is applicable to exclusive processes at energy Q 2 > 1 GeV 2. In summary, with NLO power corrections, PQCD can completely explain the Q 2 spectrum of pion form factor.
We compute various form factors involved in B → D (*) transitions based on the perturbative QCD f... more We compute various form factors involved in B → D (*) transitions based on the perturbative QCD formalism, which includes Sudakov effects from the resummation of large radiative corrections in a heavy-light system. A twoparameter model wave function for D (*) mesons is fixed using data of the nonleptonic decays B → D (*) π, from which the ratio of the decay constants f D * /f D = 0.92 is obtained. We then derive the spectrum of the semileptonic decay B → D * ℓν in the fast recoil region of the D * meson, and extract the CKM matrix element |V cb | = 0.043 × (0.12 GeV/f B) × (0.14 GeV/f D), f B and f D being the B and D meson decay constants, respectively. Here we adopt the convention with the pion decay constant f π = 93 MeV. With these outcomes, we evaluate the decay rate of B → DD s , and estimate the ratio f Ds /f D = 0.98 from data. Contributions of internal W-emission and W-exchange diagrams are briefly discussed.
We calculate the flux of nutau produced in the atmosphere by cosmic ray-air collisions. The produ... more We calculate the flux of nutau produced in the atmosphere by cosmic ray-air collisions. The production channels of nutau from the process pA -> X -> nu tau (bar nu tau )Y with X = Ds ,W±, Z, hb, tbar t , are considered. The calculations are performed by employing perturbative QCD (PQCD). The predicted nutau flux varphinutau is given
A semi-analytic approach is developed for dealing with the tau-lepton flux emerging from the Eart... more A semi-analytic approach is developed for dealing with the tau-lepton flux emerging from the Earth, induced by the incident high energy tau neutrinos interacting inside the Earth for 10 5 ≤ E ν /GeV ≤ 10 10. We obtain results for the energy dependence of the tau-lepton flux coming from the Earth-skimming neutrinos due to the neutrinonucleon charged-current interaction. We illustrate our results for several anticipated high energy astrophysical neutrino sources such as the AGNs, the GRBs, and the GZK neutrino fluxes. The tau lepton fluxes resulting from rock-skimming and ocean-skimming neutrinos are compared. Such comparisons might render useful information for the spectral indices of incident neutrino fluxes.
The mass correction forms of the arbitrary spin heavy hadrons are derived by using the projection... more The mass correction forms of the arbitrary spin heavy hadrons are derived by using the projection operator method. The Bjorken sum rule for finite mass is derived by using the results of here.
The first synthetic study on PbBiO 2 I/PbO nanocomposite preparation using a controlled hydrother... more The first synthetic study on PbBiO 2 I/PbO nanocomposite preparation using a controlled hydrothermal method is reported. The morphologies and composition of the samples are controlled by adjusting some parameters, including reaction pH, Pb/Bi molar ratio, and temperature. All the samples are characterized by XRD, TEM, XPS, SEM-EDS, PL, BET, EPR, and UV-vis-DRS. The photodegradation activities are evaluated against the de-colorization of crystal violet (CV) and 2-hydroxybenzoic acid (2-HBA) in aqueous solution under visible light illumination. In particular, the catalytic performance illustrates the best reaction rate constant 1.159 × 10 −1 h −1 once PbBiO 2 I/PbO is used as the photocatalyst for the degradation of CV; which is 3 and 20 times higher than the reaction rate constants of PbBiO 2 I and PbO being the photocatalysts, respectively. This study reveals that PbBiO 2 I/PbO can be used for repressing the recombination of photo-generated electron-hole pairs and contribute to the enhanced photocatalytic activity of semiconductors in the visible-light-driven catalysis. The possible photocatalytic degradation mechanism is studied by using different active species through EPR and adding suitable scavengers. When being irradiated, two major active species, O 2 − and 1 O 2 , and a minor active species, h + , can be produced for the CV degradation.
Journal of Molecular Catalysis A-chemical, Jun 1, 2016
This is the first report that PbBiO 2 Br/BiOBr is synthesized by a template-free hydrothermal met... more This is the first report that PbBiO 2 Br/BiOBr is synthesized by a template-free hydrothermal method. The composition and morphologies of the samples could be controlled by adjusting some growth parameters, including reaction pH, Pb/Bi molar ratio, and temperature. All the samples are characterized by XRD, TEM, XPS, SEM-EDS, FT-IR, BET, EPR, and UV-vis-DRS. The PbBiO 2 Br/BiOBr photocatalysts exhibit enhanced photocatalytic activities on the degradation of crystal violet (CV) under visible-light irradiation. In particular, the catalytic performance illustrates the best reaction rate constant 1.257 × 10 −1 h −1 once PbBiO 2 Br/BiOBr is used as the photocatalyst; which is 3 and 2 times higher than the reaction rate constant of PbBiO 2 Br and BiOBr being the photocatalysts, respectively. This study reveals that PbBiO 2 Br/BiOBr can be used to suppress the recombination of photoinduced electron-hole pairs and contribute to the enhanced photocatalytic efficiency of semiconductors in the visible-light-driven catalysis. The possible photodegradation mechanism is studied by examining different active species through EPR and adding appropriate scavengers. The results demonstrate that the reactive O 2 − plays the major and OH the minor roles in the CV degradation.
Journal of Colloid and Interface Science, Sep 1, 2018
This paper presents an unprecedented systematic synthetic study of a controlled hydrothermal meth... more This paper presents an unprecedented systematic synthetic study of a controlled hydrothermal method for the preparation of bismuth oxychloride/bismuth oxybromide/bismuth oxyiodide ternary composites (BiO x Cl y /BiO m Br n /BiO p I q). The pH, temperature, and KCl:KBr:KI molar ratio for the reactions were adjusted to control the compositions and morphologies of BiO x Cl y /BiO m Br n /BiO p I q composites. Scanning electron microscopy-energy dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, ultraviolet-visible diffuse reflectance spectroscopy, Brunauer-Emmett-Teller specific surface areas, photoluminescence spectroscopy, and X-ray photoelectron spectroscopy, and electron paramagnetic resonance spectroscopy were applied to the products. The photocatalytic activities of dispersions were examined by monitoring the 2-hydroxybenzoic acid (HBA) and crystal violet concentrations. Various scavengers 2 demonstrated quenching effects. O 2 •− was crucial to HBA degradation, whereas h + and • OH played minor roles in HBA degradation. This text hypothesizes possible photodegradation mechanisms. Keywords: Photocatalysis, BiO x Cl y /BiO m Br n /BiO p I q , composites, 2-hydroxybenzoic acid, crystal violet
The nonleptonic heavy meson decays B → D (*) π(ρ), J/ψK (*) and D → K (*) π are studied based on ... more The nonleptonic heavy meson decays B → D (*) π(ρ), J/ψK (*) and D → K (*) π are studied based on the three-scale perturbative QCD factorization theorem developed recently. In this formalism the Bauer-Stech-Wirbel parameters a 1 and a 2 are treated as the Wilson coefficients, whose evolution from the W boson mass down to the characteristic scale of the decay processes is determined by effective field theory. The evolution from the characteristic scale to a lower hadronic scale is formulated by the Sudakov resummation. The scale-setting ambiguity, which exists in the conventional approach to nonleptonic heavy meson decays, is moderated. Nonfactorizable and nonspectator contributions are taken into account as part of the hard decay subamplitudes. Our formalism is applicable to both bottom and charm decays, and predictions, including those for the ratios R and R L associated with the B → J/ψK (*) decays, are consistent with experimental data.
In this work, we propose a model by combining the parametrization method and the QCD factorizatio... more In this work, we propose a model by combining the parametrization method and the QCD factorization to study the B → πK puzzle. The parametrization for the B → πK amplitudes introduces twelve parameters, the weak angle γ and the other eleven hadronic parameters. These hadronic parameters are assumed to be perturbative and can be calculated by the QCD factorization (QCDF). The calculational accuracy of the QCDF is improved by including the twist-3 three parton tree and one loop corrections. Three additional nonperturbative strong phases from the gluonic penguin, color suppressed, and color favored tree diagrams are required to account for the direct CP asymmetries. The weak angle, three nonperturbative strong phases, and four scale variables are assumed as fitting parameters. Four scale variables represent the factorization scales for the decays, each decay mode with one scale. These eight parameters are determined by a least squares fit to the eight measurements for B → πK decays, four branching ratios and four direct CP asymmetries. The fit shows that the hadronic parameters need to be process-dependent. A large negative relative phase associated with the internal up quark gluonic penguin diagram is observed. The weak angle γ is found to be 72.1 ± 5.8 degree, being consistent with the world averaged value, 72.1 ± 5.8 degree. By a least squares fit to the mixing induced asymmetry S(π 0 KS) = 0.58 ± 0.06, the weak angle β is determined to be 22.9 ± 2.1 degree, which is in a well agreement with the world averaged value, 22.5 ± 4.4 ± 0.6 degree. The model predicts the ratio C /T (color suppressed/color favored) to be 0.59 ± 0.08. The above evidences indicate that the model can solve the B → πK puzzle consistently. The model is used to examine the quadrangle relation of the isospin symmetry assumed for the B → πK system. The ratio of the two sides of the quadrangle relation is calculated to be (0.87±0.15) exp(−i22 •), which signals the isospin symmetry breaking at 6σ. The process-dependent hadronic parameters break the isospin symmetry "dynamically". The application of our method to other decay processes is straightforward.
We present a first perturbative evaluation on the next-to-leading-order (NLO) $O(1/Q^4)$ power co... more We present a first perturbative evaluation on the next-to-leading-order (NLO) $O(1/Q^4)$ power corrections of the photon-pion transition form factor $F_{\pi\gamma}(Q^2)$. There involve four next-to-leading-twist (NLT) distribution amplitudes (DAs). A power expansion, which is compatible with QCD factorization, is built and employed for calculations.
The polarization of Λ b baryon has been measured in ALEPH, OPAL and DELPHI experiments. A signifi... more The polarization of Λ b baryon has been measured in ALEPH, OPAL and DELPHI experiments. A significant loss on the transfer of the b quark polarization to the Λ b baryon polarization has been noticed. This implies that the hadronization effects can not be neglected. Therefore, we may make use of the polarization measurements to look for suitable model for the Λ b distribution function. To investigate nonperturbative effects implied in the Λ b polarization, we construct four models based on a perturbative QCD factorization formula. The models are the quark model (QM), the modified quark model (MQM), the parton model (PM), and the modified parton model (MPM). The modified models mean the models having transverse degrees of freedom and the associated soft radiative corrections having been resummed. The quark and parton models can not describe all experiments in the same time. On the other hand, the modified models can have the power to explain all data in the same formalism.
We propose a perturbative evaluation for the next-toleading-order (NLO) O(1/Q 4) power correction... more We propose a perturbative evaluation for the next-toleading-order (NLO) O(1/Q 4) power correction to the photon pion transition form factor Fπγ (Q 2). The effects of the NLO power correction are analyzed.
An ecofriendly and cheap photocatalyst is crucial for realizing practical photocatalysis applicat... more An ecofriendly and cheap photocatalyst is crucial for realizing practical photocatalysis applications. Many inorganic materials have modular structures in which individual units are responsible for different functions. [Bi 2 O 2 ] 2+ slabs with an α-PbO-type structure and simple halide layers are effective spacers in some layered functional materials. Previous reports have mainly discussed electronic reasons for the different photocatalytic activities of layered PbBiO 2 X-type materials (X = Cl, Br, I). To the best of our knowledge, nanocomposite semiconductors consisting of PbBiO 2 I/g-C 3 N 4 have not been reported in the literature. In this study, PbBiO 2 X/g-C 3 N 4 composites were isolated and characterized by FE-SEM-EDS, XRD, HR-XPS, TEM, PL, BET, FT-IR, and UV-vis-DRS. By degrading crystal violet (CV) and 2-hydroxybenzoic acid (HBA) in an aqueous solution under visible-light irradiation, the photocatalytic activities of PbBiO 2 I/g-C 3 N 4 are discussed further. In particular, the catalytic performance illustrates the best reaction rate constants of 0.3259 h −1 using the PbBiO 2 I/g-C 3 N 4 composite as the photocatalysts; these are 13.7 and 9.1 times higher than those of PbBiO 2 I and g-C 3 N 4 , respectively. The quenching effects of different scavenger results demonstrate that reactive O 2 %− plays the major role and % OH, h + , and 1 O 2 play the minor role in CV degradation.
In many years ago, Isgur and Llewellyn Smith addressed that PQCD is inapplicable to exclusive pro... more In many years ago, Isgur and Llewellyn Smith addressed that PQCD is inapplicable to exclusive processes [1,2], such as the pion form factor. The main problem is that the asymptotic of PQCD is only about one fourth of the experimental value [3-5]. We reexamine this PQCD deep problem. By including NLO power corrections to the pion form factor, we may arrive at a perturbative explanation for the data. The key realization is that we need to interprete that the strong interaction coupling constant involved in the PQCD result should be taken as an effective coupling constant under nonperturbative QCD vaccum. This implies that one can equally identify the relevant scale for the effective coupling constant as the factorization scale about 1 GeV. We also find that the average momentum fraction variable locates about 0.5, which is in favor of the asymptotic pion wave function. By employing photon-pion form factor with NLO power corrections to factorize out the nonperturbative effects involved in the effective coupling constant, we can extract an effective running coupling constant, which represents an effective coupling involving in the hard scattering subprocesses. The difference between the effective running coupling constant and the usual perturbative running coupling constant (Λ QCD = 0.3 GeV) is very small for Q 2 > 1 GeV 2. The effective running coupling constant αs/π is smaller than 0.2 for Q 2 > 1 GeV 2. This directly showes that PQCD is applicable to exclusive processes at energy Q 2 > 1 GeV 2. In summary, with NLO power corrections, PQCD can completely explain the Q 2 spectrum of pion form factor.
We compute various form factors involved in B → D (*) transitions based on the perturbative QCD f... more We compute various form factors involved in B → D (*) transitions based on the perturbative QCD formalism, which includes Sudakov effects from the resummation of large radiative corrections in a heavy-light system. A twoparameter model wave function for D (*) mesons is fixed using data of the nonleptonic decays B → D (*) π, from which the ratio of the decay constants f D * /f D = 0.92 is obtained. We then derive the spectrum of the semileptonic decay B → D * ℓν in the fast recoil region of the D * meson, and extract the CKM matrix element |V cb | = 0.043 × (0.12 GeV/f B) × (0.14 GeV/f D), f B and f D being the B and D meson decay constants, respectively. Here we adopt the convention with the pion decay constant f π = 93 MeV. With these outcomes, we evaluate the decay rate of B → DD s , and estimate the ratio f Ds /f D = 0.98 from data. Contributions of internal W-emission and W-exchange diagrams are briefly discussed.
We calculate the flux of nutau produced in the atmosphere by cosmic ray-air collisions. The produ... more We calculate the flux of nutau produced in the atmosphere by cosmic ray-air collisions. The production channels of nutau from the process pA -> X -> nu tau (bar nu tau )Y with X = Ds ,W±, Z, hb, tbar t , are considered. The calculations are performed by employing perturbative QCD (PQCD). The predicted nutau flux varphinutau is given
A semi-analytic approach is developed for dealing with the tau-lepton flux emerging from the Eart... more A semi-analytic approach is developed for dealing with the tau-lepton flux emerging from the Earth, induced by the incident high energy tau neutrinos interacting inside the Earth for 10 5 ≤ E ν /GeV ≤ 10 10. We obtain results for the energy dependence of the tau-lepton flux coming from the Earth-skimming neutrinos due to the neutrinonucleon charged-current interaction. We illustrate our results for several anticipated high energy astrophysical neutrino sources such as the AGNs, the GRBs, and the GZK neutrino fluxes. The tau lepton fluxes resulting from rock-skimming and ocean-skimming neutrinos are compared. Such comparisons might render useful information for the spectral indices of incident neutrino fluxes.
The mass correction forms of the arbitrary spin heavy hadrons are derived by using the projection... more The mass correction forms of the arbitrary spin heavy hadrons are derived by using the projection operator method. The Bjorken sum rule for finite mass is derived by using the results of here.
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Papers by Tsung-Wen Yeh