Application of Echocardiography on Transgenic Mice with Cardiomyopathies

Cardiomyopathies are common cardiac disorders that primarily affect cardiac muscle resulting in cardiac dysfunction and heart failure. Transgenic mouse disease models have been developed to investigate the cellular mechanisms underlying heart failure and sudden cardiac death observed in cardiomyopathy cases and to explore the therapeutic outcomes in experimental animals in vivo. Echocardiography is an essential diagnostic tool for accurate and noninvasive assessment of cardiac structure and function in experimental animals. Our laboratory has been among the first to apply high-frequency research echocardiography on transgenic mice with cardiomyopathies. In this work, we have summarized our and other studies on assessment of systolic and diastolic dysfunction using conventional echocardiography, pulsed Doppler, and tissue Doppler imaging in transgenic mice with various cardiomyopathies. Estimation of embryonic mouse hearts has been performed as well using this high-resolution echocardiography. Some technical considerations in mouse echocardiography have also been discussed

Heavy-to-light baryonic form factors at large recoil

We analyze heavy-to-light baryonic form factors at large recoil and derive the scaling behavior of these form factors in the heavy quark limit. It is shown that only one universal form factor is needed to parameterize Lambda_b to p and Lambda_b to Lambda matrix elements in the large recoil limit of light baryons, while hadronic matrix elements of Lambda_b to Sigma transition vanish in the large energy limit of Sigma baryon due to the space-time parity symmetry. The scaling law of the soft form factor eta(P^{\prime} \cdot v), P^{\prime} and v being the momentum of nucleon and the velocity of Lambda_b baryon, responsible for Lambda_b to p transitions is also derived using the nucleon distribution amplitudes in leading conformal spin. In particular, we verify that this scaling behavior is in full agreement with that from light-cone sum rule approach in the heavy-quark limit. With these form factors, we further investigate the Lambda baryon polarization asymmetry alpha in Lambda_b to Lambda gamma and the forward-backward asymmetry A_{FB} in Lambda_b to Lambda l^{+} l^{-}. Both two observables (alpha and A_{FB}) are independent of hadronic form factors in leading power of 1/m_b and in leading order of alpha_s. We also extend the analysis of hadronic matrix elements for Omega_b to Omega transitions to rare Omega_b to Omega gamma and Omega_b to Omega l^{+} l^{-} decays and find that radiative Omega_b to Omega gamma decay is probably the most promising FCNC b to s radiative baryonic decay channel. In addition, it is interesting to notice that the zero-point of forward-backward asymmetry of Omega_b to Omega l^{+} l^{-} is the same as the one for Lambda_b to Lambda l^{+} l^{-} to leading order accuracy provided that the form factors \bar{\zeta}_i (i=3, 4, 5) are numerically as small as indicated from the quark model.Comment: 19 page

Physics at BES-III

This physics book provides detailed discussions on important topics in $\tau$-charm physics that will be explored during the next few years at \bes3 . Both theoretical and experimental issues are covered, including extensive reviews of recent theoretical developments and experimental techniques. Among the subjects covered are: innovations in Partial Wave Analysis (PWA), theoretical and experimental techniques for Dalitz-plot analyses, analysis tools to extract absolute branching fractions and measurements of decay constants, form factors, and CP-violation and \DzDzb-oscillation parameters. Programs of QCD studies and near-threshold tau-lepton physics measurements are also discussed.Comment: Edited by Kuang-Ta Chao and Yi-Fang Wan

New Physics in b -> s mu+ mu-: CP-Conserving Observables

We perform a comprehensive study of the impact of new-physics operators with different Lorentz structures on decays involving the b -> s mu+ mu- transition. We examine the effects of new vector-axial vector (VA), scalar-pseudoscalar (SP) and tensor (T) interactions on the differential branching ratios and forward-backward asymmetries (A_{FB}'s) of Bsbar -> mu+ mu-, Bdbar -> Xs mu+ mu-, Bsbar -> mu+ mu- gamma, Bdbar -> Kbar mu+ mu-, and Bdbar -> K* mu+ mu-, taking the new-physics couplings to be real. In Bdbar -> K* mu+ mu-, we further explore the polarization fraction f_L, the angular asymmetry A_T^{(2)}, and the longitudinal-transverse asymmetry A_{LT}. We identify the Lorentz structures that would significantly impact these observables, providing analytical arguments in terms of the contributions from the individual operators and their interference terms. In particular, we show that while the new VA operators can significantly enhance most of the asymmetries beyond the Standard Model predictions, the SP and T operators can do this only for A_{FB} in Bdbar -> Kbar mu+ mu-.Comment: 54 pages, JHEP format, 45 figures (included). 5/6/2013: typos in K* mu mu angular coefficients corrected, typos in Eq. (D.12) corrected, added a missing term in I3LT in Eq. (D.16). Numerical analysis unchange

Heavy to Light Meson Exclusive Semileptonic Decays in Effective Field Theory of Heavy Quark

We present a general study on exclusive semileptonic decays of heavy (B, D, B_s) to light (pi, rho, K, K^*) mesons in the framework of effective field theory of heavy quark. Transition matrix elements of these decays can be systematically characterized by a set of wave functions which are independent of the heavy quark mass except for the implicit scale dependence. Form factors for all these decays are calculated consistently within the effective theory framework using the light cone sum rule method at the leading order of 1/m_Q expansion. The branching ratios of these decays are evaluated, and the heavy and light flavor symmetry breaking effects are investigated. We also give comparison of our results and the predictions from other approaches, among which are the relations proposed recently in the framework of large energy effective theory.Comment: 18 pages, ReVtex, 5 figures, added references and comparison of results, and corrected signs in some formula

The potential of a mobile group blog to support cultural learning among overseas students

We explored the use of mobile social software, in the form of a mobile group blog, to assist cultural learning. The potential of using this technology for cultural adaptation among overseas students was examined as those students adapted to the everyday life of studying abroad. Two pilot studies and a successful field study of a mobile group blog as used by UK overseas students are reported. A further study with prospective overseas students witnessing this ‘moblogging’ in China revealed the advantages of communicating through this technology as a form of peer-supported preparation for cultural adaptation. Potential advantages for learning a second language via this system, were highlighted as communication was interweaved with cultural adaptation and exercised in the blog entries. Given mobile internet, the language experience together with cultural observation impressively supported these students' growing confidence with time, space and imagination

Production of intermediate-mass dileptons in relativistic heavy ion collisions

The production of intermediate mass dileptons in ultrarelativistic nuclear collisions at SPS energies is studied. The acceptance and detector resolution inherent to measurements by the NA50 experimental collaboration are accurately modeled. The measured centrality dependence of the intermediate mass lepton pair excess is also addressed.Comment: 9 pages, 8 figures, ReVTe

Direct CP Violation, Branching Ratios and Form Factors B→πB \to \pi, B→KB \to K in BB Decays

The $B \to \pi$ and $B \to K$ transitions involved in hadronic B decays are investigated in a phenomenological way through the framework of QCD factorization. By comparing our results with experimental branching ratios from the BELLE, BABAR and CLEO Collaborations for all the B decays including either a pion or a kaon, we propose boundaries for the transition form factors $B \to \pi$ and $B \to K$ depending on the CKM matrix element parameters $\rho$ and $\eta$. From this analysis, the form factors required to reproduce the experimental data for branching ratios are $F^{B \to \pi}= 0.31 \pm 0.12$ and $F^{B \to K}= 0.37\pm 0.13$. We calculate the direct CP violating asymmetry parameter, $a_{CP}$, for $B \to \pi^{+} \pi^{-} \pi$ and $B \to \pi^{+} \pi^{-} K$ decays, in the case where $\rho-\omega$ mixing effects are taken into account. Based on these results, we find that the direct CP asymmetry for $B^{-} \to \pi^{+} \pi^{-} \pi^{-}$, $\bar{B}^{0} \to \pi^{+} \pi^{-} \pi^{0}$, $B^{-} \to \pi^{+} \pi^{-} K^{-}$, and $\bar{B}^{0} \to \pi^{+} \pi^{-} \bar{K}^{0}$, reaches its maximum when the invariant mass $\pi^{+} \pi^{-}$ is in the vicinity of the $\omega$ meson mass. The inclusion of $\rho-\omega$ mixing provides an opportunity to erase, without ambiguity, the phase uncertainty mod$(\pi)$ in the determination of the CKM angles $\alpha$ in case of $b\to u$ and $\gamma$ in case of $b \to s$.Comment: 74 pages, 15 figures, 8 tables. A few misprints corrected, two references adde

Phenomenology of non-standard Z couplings in exclusive semileptonic b -> s transitions

The rare decays $B\to K^{(*)}\ell^+\ell^-$, $B\to K^{(*)}\nu\bar\nu$ and $B_s\to\mu^+\mu^-$ are analyzed in a generic scenario where New Physics effects enter predominantly via $Z$ penguin contributions. We show that this possibility is well motivated on theoretical grounds, as the $\bar sbZ$ vertex is particularly susceptible to non-standard dynamics. In addition, such a framework is also interesting phenomenologically since the $\bar sbZ$ coupling is rather poorly constrained by present data. The characteristic features of this scenario for the relevant decay rates and distributions are investigated. We emphasize that both sign and magnitude of the forward-backward asymmetry of the decay leptons in $\bar B\to \bar K^*\ell^+\ell^-$, ${\cal A}^{(\bar B)}_{FB}$, carry sensitive information on New Physics. The observable ${\cal A}^{(\bar B)}_{FB}+{\cal A}^{(B)}_{FB}$ is proposed as a useful probe of non-standard CP violation in $\bar sbZ$ couplings.Comment: Minor modifications; version to appear in Phys. Rev.

Intermediate-mass dilepton spectra and the role of secondary hadronic processes in heavy-ion collisions

We carry out a study of intermediate-mass (between 1 and 2.5 GeV) dilepton spectra from hadronic interactions in heavy-ion collisions. The processes considered are $\pi\pi\to l{\bar l}$, $\pi\rho\to l{\bar l}$, $\pi a_1\to l{\bar l}$, $\pi\omega\to l{\bar l}$, $K{\bar K}\to l{\bar l}$, and $K{\bar K^*}+c.c \to l{\bar l}$. The elementary cross sections for those are obtained from chiral Lagrangians involving pseudoscalar, vector, and axial-vector mesons. The respective electromagnetic form factors are determined by fitting to experimental data for the reverse processes of $e^+e^-\to hadrons$. Based on this input we calculate cross sections and thermal dilepton emission rates and compare our results with those from other approaches. Finally we use these elementary cross sections with a relativistic transport model and calculate dilepton spectra in S+W collisions at SPS energies. The comparison of our results with experimental data from the HELIOS-3 collaboration indicates the importance of the secondary hadronic contributions to the intermediate-mass dilepton spectra.Comment: 25 pages, including 20 postscript figure