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Search Results: 1 - 10 of 147088 matches for " LI Xin-Qiang "
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Reliability and Validity of the Student Teacher Professional Identity Scale in Pre-Service Kindergarten Teachers  [PDF]
Li-Ying Zhang, Xin-Qiang Wang
Open Journal of Social Sciences (JSS) , 2018, DOI: 10.4236/jss.2018.68021
Abstract: Objective: To revise and explore the application of the student teacher professional identity scale in pre-service kindergarten teachers (STPIS-PK). Methods: 450 preservice kindergarten teachers were surveyed by the student teacher professional identity scale. Results: 1) The EFA supported that teacher professional identity consisted of four subscales: professional values, professional willingness, professional efficiency and professional volition. Also the CFA confirmed the hypothesized four-factor model (x2 = 133.277, x2/df = 2.777, CFI = 0.939, TLI = 0.901, RMSEA = 0.047). The Criteria-related validity was remarkable; 2) The internal consistency of teacher professional identity scale was 0.801 and the four subscales were from 0.628 to 0.789. For two weeks, the test-retest reliability was from 0.616 to 0.786. Conclusion: In sum, this study generated evidence that the STPIS-PK developed in the study is a psychometrically sound and valid instruments to measure pre-service kindergarten teachers’ professional identity.
Revisiting B\to\pi K, \pi K^{\ast} and \rho K decays: CP violations and implication for New Physics
Chang, Qin;Li, Xin-Qiang;Yang, Ya-Dong
High Energy Physics - Phenomenology , 2008, DOI: 10.1088/1126-6708/2008/09/038
Abstract: Combining the up-to-date experimental information on $B\to\pi K, \pi K^{\ast}$ and $\rho K$ decays, we revisit the decay rates and CP asymmetries of these decays within the framework of QCD factorization. Using an infrared finite gluon propagator of Cornwall prescription, we find that the time-like annihilation amplitude could contribute a large strong phase, while the space-like hard spectator scattering amplitude is real. Numerically, we find that all the branching ratios and most of the direct CP violations, except $A_{CP}(B^{\pm}\to K^{\pm}\pi^{0})$, agree with the current experimental data with an effective gluon mass $m_g\simeq0.5 {\rm GeV}$. Taking the unmatched difference in direct CP violations between $B\to\pi^{0} K^{\pm}$ and $\pi^{\mp}K^{\pm}$ decays as a hint of new physics, we perform a model-independent analysis of new physics contributions with a set of $\bar{s}(1+\gamma_{5})b\otimes\bar{q}(1+\gamma_{5})q$ (q=u,d) operators. Detail analyses of the relative impacts of the operators are presented in five cases. Fitting the twelve decay modes, parameter spaces are found generally with nontrivial weak phases. Our results may indicate that both strong phase from annihilation amplitude and new weak phase from new physics are needed to resolve the $\pi K$ puzzle. To further test the new physics hypothesis, the mixing-induced CP violations in $B\to\pi^{0}K_{S}$ and $\rho^{0}K_{S}$ are discussed and good agreements with the recent experimental data are found.
B -> D(*) Tau Nu decays in two-Higgs-doublet models
Celis, Alejandro;Jung, Martin;Li, Xin-Qiang;Pich, Antonio
High Energy Physics - Phenomenology , 2013,
Abstract: A sizable excess with respect to the SM expectation has been reported recently by the BaBar collaboration in the decay rates B -> D(*) Tau Nu, normalized by the corresponding light lepton modes. A violation of lepton flavor universality as suggested by this excess could be due to a charged Higgs mediating these processes at tree level. In this talk we analyze the implications of the observed excess within the framework of two-Higgs-doublet models, considering also the bounds from other semileptonic and leptonic decays of B and D(s) mesons. Prospects for B -> D(*) Tau Nu decays at future Super-Flavor Factories are also discussed.
Two-loop QCD correction to differential semi-leptonic b --> u decays in the shape-function region
Beneke, M.;Huber, T.;Li, Xin-Qiang
High Energy Physics - Phenomenology , 2008, DOI: 10.1016/j.nuclphysb.2008.11.019
Abstract: We calculate the two-loop QCD correction to the form factors of on-shell b-quark decay to an energetic massless quark, which constitutes the last missing piece required for an O(alpha_s^2) determination of |V_ub| from inclusive semi-leptonic \bar B --> X_u l nu decays in the shape-function region.
NNLO vertex corrections to non-leptonic B decays: Tree amplitudes
M. Beneke,T. Huber,Xin-Qiang Li
Physics , 2009, DOI: 10.1016/j.nuclphysb.2010.02.002
Abstract: The colour-suppressed tree amplitude in non-leptonic B decays is particularly sensitive to perturbative and non-perturbative corrections. We calculate the two-loop (NNLO) vertex corrections to the colour-suppressed and colour-allowed tree amplitudes in QCD factorization. Our results are given completely analytically, including the full dependence on the charm quark mass. We then update theoretical predictions for a range of interesting observables derived from pi pi, pi rho, and rho rho final states that do not depend (significantly) on penguin contributions, and hence are now available with NNLO accuracy. We observe good agreement with experimental data within experimental and theoretical errors, except for observables involving the pi^0 pi^0 branching fraction.
The effects of a family non-universal Z-prime boson on B--->pipi decays
Qin Chang,Xin-Qiang Li,Ya-Dong Yang
Physics , 2010, DOI: 10.1142/S0217751X11051573
Abstract: Motivated by the measured large branching ratio of $\bar{B}^{0}\to\pi^0\pi^0$ (the so-called "$\pi\pi$" puzzle), we investigate the effects of a family non-universal $Z^{\prime}$ model on the tree-dominated $B\to\pi\pi$ decays. We find that the $Z^{\prime}$ coupling parameter $\zeta_{d}^{LR}\sim0.05$ with a nontrivial new weak phase $\phi_d^L\sim-50^{\circ}$, which is relevant to the $Z^{\prime}$ contributions to the QCD penguin sector $\triangle C_5$, is needed to reconcile the observed discrepancy. Combined with the recent fitting results from $B\to\pi K$, $\pi K^{\ast}$ and $\rho K$ decays, the $Z^{\prime}$ parameter spaces are severely reduced but still not excluded entirely, implying that both the "$\pi\pi$" and "$\pi K$" puzzles could be accommodated simultaneously within such a family non-universal $Z^{\prime}$ model.
B -> D(*) Tau Nu decays in two-Higgs-doublet models
Alejandro Celis,Martin Jung,Xin-Qiang Li,Antonio Pich
Physics , 2013, DOI: 10.1088/1742-6596/447/1/012058
Abstract: A sizable excess with respect to the SM expectation has been reported recently by the BaBar collaboration in the decay rates B -> D(*) Tau Nu, normalized by the corresponding light lepton modes. A violation of lepton flavor universality as suggested by this excess could be due to a charged Higgs mediating these processes at tree level. In this talk we analyze the implications of the observed excess within the framework of two-Higgs-doublet models, considering also the bounds from other semileptonic and leptonic decays of B and D(s) mesons. Prospects for B -> D(*) Tau Nu decays at future Super-Flavor Factories are also discussed.
Heavy-to-light currents at NNLO in SCET and semi-inclusive anti-B ---> X(s) l+ l- decay
G. Bell,M. Beneke,T. Huber,Xin-Qiang Li
Physics , 2010, DOI: 10.1016/j.nuclphysb.2010.09.022
Abstract: We perform the two-loop matching calculation for heavy-to-light currents from QCD onto soft-collinear effective theory for the complete set of Dirac structures. The newly obtained matching coefficients enter several phenomenological applications, of which we discuss heavy-to-light form factor ratios and exclusive radiative decays, as well as the semi-inclusive decay anti-B ---> X(s) l+ l-. For this decay, we observe a significant shift of the forward-backward asymmetry zero and find q_0^2 = (3.34 +0.22 -0.25) GeV^2 for an invariant mass cut m_X^cut=2.0 GeV.
Sensitivity to charged scalars in $B\to D^{(*)}τν_τ$ and $B\toτν_τ$ decays
Alejandro Celis,Martin Jung,Xin-Qiang Li,Antonio Pich
Physics , 2012, DOI: 10.1007/JHEP01(2013)054
Abstract: We analyze the recent experimental evidence for an excess of $\tau$-lepton production in several exclusive semileptonic $B$-meson decays in the context of two-Higgs-doublet models. These decay modes are sensitive to the exchange of charged scalars and constrain strongly their Yukawa interactions. While the usual Type-II scenario cannot accommodate the recent BaBar data, this is possible within more general models in which the charged-scalar couplings to up-type quarks are not as suppressed. Both the $B\to D^{(*)}\tau\nu_\tau$ and the $B\to\tau\nu_\tau$ data can be fitted within the framework of the Aligned Two-Higgs-Doublet Model, but the resulting parameter ranges are in conflict with the constraints from leptonic charm decays. This could indicate a departure from the family universality of the Yukawa couplings, beyond their characteristic fermion mass dependence. We discuss several new observables that are sensitive to a hypothetical charged-scalar contribution, demonstrating that they are well suited to distinguish between different scenarios of new physics in the scalar sector, and also between this group and models with different Dirac structures; their experimental study would therefore shed light on the relevance of scalar exchanges in semileptonic $b\to c\,\tau^-\bar\nu_\tau$ transitions.
$B_{s,d}^0 \to \ell^+\ell^-$ Decays in the Aligned Two-Higgs-Doublet Model
Xin-Qiang Li,Jie Lu,Antonio Pich
Physics , 2014, DOI: 10.1007/JHEP06(2014)022
Abstract: The rare decays $B_{s,d}^0 \to \ell^+\ell^-$ are analyzed within the general framework of the aligned two-Higgs doublet model. We present a complete one-loop calculation of the relevant short-distance Wilson coefficients, giving a detailed technical summary of our results and comparing them with previous calculations performed in particular limits or approximations. We investigate the impact of various model parameters on the branching ratios and study the phenomenological constraints imposed by present data.
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