Charm meson resonances in D→PℓνD \to P \ell \nu decays

Motivated by recent experimental results we reconsider semileptonic $D \to P \ell \nu_{\ell}$ decays within a model which combines heavy quark symmetry and properties of the chiral Lagrangian. We include excited charm meson states, some of them recently observed, in our Lagrangian and determine their impact on the charm meson semileptonic form factors. We find that the inclusion of excited charm meson states in the model leads to a rather good agreement with the experimental results on the $q^2$ shape of the $F_+(q^2)$ form factor. We also calculate branching ratios for all $D \to P \ell \nu_{\ell}$ decays.Comment: 9 pages, 4 figures; minor corrections, added some discussion, version as publishe

Exclusive B→PVB \to PV Decays and CP Violation in the General two-Higgs-doublet Model

We calculate all the branching ratios and direct CP violations of $B \to PV$ decays in a most general two-Higgs-doublet model with spontaneous CP violation. As the model has rich CP-violating sources, it is shown that the new physics effects to direct CP violations and branching ratios in some channels can be significant when adopting the generalized factorization approach to evaluate the hadronic matrix elements, which provides good signals for probing new physics beyond the SM in the future B experiments.Comment: 21 page

Stokes Vector of Photon in the Decays B^0 -> rho^0 gamma and B^0 -> K^* gamma

We consider a model for the decay Bbar^0 -> rho^0 gamma in which the short-distance amplitude determined by the Hamiltonian describing b -> d gamma is combined with a typical long-distance contribution Bbar^0 -> D^+ D^- -> rho^0 gamma. The latter possesses a significant dynamical phase which induces a CP-violating asymmetry A_CP, as well as an important modification of the Stokes vector of the photon. The components S_1 and S_3 of the Stokes vector S = (S_1, S_2, S_3) can be measured in the decay Bbar^0 -> rho^0 gamma^* -> pi^+ pi^- e^+ e^- where they produce a characteristic effect in the angular distribution d Gamma / d phi, phi being the angle between the pi^+ pi^- and e^+ e^- planes. A similar analysis is carried out for the decays Bbar^0 -> Kbar^* gamma and Bbar^0 -> Kbar^* gamma^* -> pi^+ K^- e^+ e^-Comment: 13 pages, 8 figures; v2: Some clarifying remarks added, together with additional references. Minor typos corrected. No change in result

Chondrosarcoma of the Pelvis: Oncologic and Functional Outcome

Purpose. Chondrosarcoma (CS) most commonly involves the pelvis. The factors that influence local and systemic control of pelvic CS and the functional outcome should be evaluated

Semileptonic and Exclusive Rare B Decays

The exclusive rare decay B \ra K^\ast \gamma takes place in a region of maximum recoil, $q^{2}=0$, posing a problem for nonrelativistic quark models which are usually thought to be most reliable at zero recoil. The Bauer--Stech--Wirbel (BSW) model, formulated in the infinite--momentum--frame (IMF) formalism, is designed to work at $q^2=0$. We show in this model that the ratio relating the decay B \ra K^\ast \gamma and the $q^2$--spectrum of the semileptonic decay B\ra \rho e {\bar \nu}, becomes independent of the wave function in the SU(3) flavor symmetry limit. We show that this feature is also true in relativistic quark models formulated in the IMF or light--cone formalism, if the $b$ quark is infinitely heavy. In fact, these relativistic models, which have a different spin structure from the BSW case, reduce to the BSW model in the heavy $b$--quark limit. A direct measurement of the $q^2$--spectrum of the semileptonic decay can therefore provide accurate information for the exclusive rare decay.Comment: 13 pages, Latex, no figure, UTPT--94--0

Final State Interactions in D0→K0K0ˉD^0 \to K^0 \bar{K^0}

It is believed that the production rate of $D^0\to K^0\bar K^0$ is almost solely determined by final state interactions (FSI) and hence provides an ideal place to test FSI models. Here we examine model calculations of the contributions from s-channel resonance $f_J(1710)$ and t-channel exchange to the FSI effects in $D^0\to K^0\bar K^0$. The contribution from s-channel $f_0(1710)$ is sma$For the t-channel FSI evaluation, we employ the one-particle-exchange (OPE) model and Regge model respecti$ The results from two methods are roughly consistent with each other and can reproduce the large rate of $D^0\to K^0\bar K^0$ reasonably well$Comment: Latex, 16 pages, with 2 figure

Selection rules in three-body B decay from factorization

Extending the dynamics underlying the factorization calculation of two-body decays, we propose simple selection rules for nonresonant three-body B decays. We predict, for instance, that in the Dalitz plot of B^0-->D^0-bar\pi^+\pi^-, practically no events should be found in the corner of E(\pi^+) < \Lambda_{QCD} as compared with the corner of E(\pi^-) < \Lambda_{QCD}. We also predict that there should be very few three-body decay events with a soft meson resonance and two energetic mesons or meson resonances. The selection rules are quite different from the soft pion theorem, since they apply to different kinematical regions. For B^0 -->D^0-bar\pi^+\pi^-, the latter predicts that the decay matrix element vanishes in the zero-four-momentum limit of \pi^+ instead of \pi^-. Since this marked difference from the soft pion theorem is directly related to the issue of short-distance QCD dominance in the FSI of two-body B decays, experimental test of the selection rules will shed light on strong interaction dynamics of B decay.Comment: 12 pages in REVTEX including 3 eps figure

A Model for the decay of the Ds+D_s^{+} meson into three pions,

We propose a phenomenological two component model describing the decay amplitude of the process D_s^{+} \ra 3 \pi, whose rate has been found surprisingly large. The first component is a constant background $F_{NR}$, and the second one is a Breit-Wigner type amplitude associated to a quasi two body $f_0(980)$ $\pi^{+}$ state. We show that it is possible to reproduce the observed rate for D_s^{+} \ra \pi^{+}\pi^{+}\pi^{-} as well as the two other measured branching ratios for the non resonant part and the resonant $f_0\pi^{+}$ one, with a common parameter $F_{NR}$. Predictions are given for the D_s^{+} \ra \pi^{0}\pi^{0}\pi^{+} rates, as well as for the various $\pi^{+}$ and $\pi^{-}$, or $\pi^{0}$ and $\pi^{+}$ energy distributions for the two possible final states.Comment: 23 pages (Latex) including 7 figures (Postscript file)

Final state rescattering as a contribution to B→ργB \to \rho \gamma

We provide a new estimate of the long-distance component to the radiative transition $B \to \rho \gamma$. Our mechanism involves the soft-scattering of on-shell hadronic products of nonleptonic $B$ decay, as in the chain $B \to \rho\rho \to \rho\gamma$. We employ a phenomenological fit to scattering data to estimate the effect. The specific intermediate states considered here modify the $B \to \rho \gamma$ decay rate at roughly the $5 \to 8$ level, although the underlying effect has the potential to be larger. Contrary to other mechanisms of long distance physics which have been discussed in the literature, this yields a non-negligible modification of the $B^0 \to \rho^0 \gamma$ channel and hence will provide an uncertainty in the extraction of $V_{td}$. This mechanism also affects the isospin relation between the rates for $B^- \to \rho^-\gamma$ and $B^0 \to \rho^0 \gamma$ and may generate CP asymmetries at experimentally observable levels.Comment: 15 pages, RevTex, 3 figure

B-physics constraints on baryon number violating couplings: grand unification or R-parity violation

We investigate the role that baryon number violating interactions may play in $B$ phenomenology. Present in various grand unified theories, supersymmetric theories with R-parity violation and composite models, a diquark state could be quite light. Using the data on B decays as well as $B - {\bar B}$ mixing, we find strong constraints on the couplings that such a light diquark state may have with the Standard Model quarks.Comment: 19 pages, latex, no figures, 13 tables include