Extracting |V_{ub}| from the Hadronic Mass Spectrum of Inclusive B decays

Following a strategy introduced earlier by the authors, we show that it is possible to extract |V_{ub}| from the cut hadronic mass spectrum of B decays without large systematic errors which usually arise from having to model the Fermi motion of the heavy quark. We present a closed form expression for |V_{ub}|/|V_{ts}| which is accurate up to corrections of order \alpha_s^2, \alpha_s \rho, (\Lambda/m_b)^2/\rho, where \rho is the experimental cut (s_c/m_b^2) on the hadronic mass used to veto charmed decays. Modulo duality violation errors, which are intrinsic to all inclusive predictions, we estimate the theoretical error in the extraction to be at the 5% level.Comment: 11 pages, 1 figur

A Comment on the Extractions of V_{ub} from Radiative Decays

We present a model independent closed form expression for |V_{ub}|^2/|V_{tb} V_{ts}^*|^2, which includes the resummation of large endpoint logarithms as well as the interference effects from the operators $O_2$ and $O_8$. We demonstrate that the method to extract |V_{ub}| presented by the authors in hep-ph/9909404, and modified in this letter to include interference effects, is not just a refinement of the method introduced in hep-ph/9312311. We also discuss the model dependence of the latter proposal. Furthermore, we show that the resummation is not negligible and that the Landau pole does not introduce any significant uncertainties.Comment: 10 pages, 3 figures; one figure added, one reference added, expanded discussion

Eikonal Wave Functions and Model Independent Exclusive B Decays

In this letter we investigate the proper normalization for the B meson eikonal valence wave function used in exclusive B decays. The normalization appropriate for a hard scattering process renormalized at the scale $\mu$ is determined by calculating the short distance contribution to the purely leptonic decay.Comment: 8 pages (3 figures available upon request), UM-TH-94-0

Spin induced multipole moments for the gravitational wave flux from binary inspirals to third Post-Newtonian order

Using effective field theory techniques we calculate the source multipole moments needed to obtain the spin contributions to the power radiated in gravitational waves from inspiralling compact binaries to third Post-Newtonian order (3PN). The multipoles depend linearly and quadratically on the spins and include both spin(1)spin(2) and spin(1)spin(1) components. The results in this paper provide the last missing ingredient required to determine the phase evolution to 3PN including all spin effects which we will report in a separate paper.Comment: 35 pages, 7 figures. Published versio

Closing the Windows on Mev Tau Neutrinos

In this note, we analyze various constraints on the ``visible'' decay modes of a massive $\tau$ neutrino, $\nu_\tau\rightarrow\nu^\prime\,\gamma$ and $\nu_\tau\rightarrow\nu^\prime\, e^+ e^-$, where $\nu^\prime$ is a light neutrino. The BEBC beam dump experiment provides model-independent constraints on these modes. The lifetime for the $\nu^\prime\, e^+e^-$ mode is constrained to be $\tau_{\nu^\prime\, e^+e^-} \ge 0.18~(m_{\nu_\tau}/MeV)~sec.$ We point out that the same experiment implies a similar constraint on the $\nu^\prime\,\gamma$ mode. This results in a new upper limit on the transition magnetic moment of $\nu_\tau$, $\mu_{\rm tran} \le 1.1 \times 10^{-9} (MeV/m_{\nu_\tau})^2 \mu_B$. Furthermore, a limit on the electric charge of $\nu_\tau$ may be obtained, $Q_{\nu_\tau} \le 4 \times 10^{-4}e$. Combining these constraints with those arising from supernova observations and primordial nucleosynthesis calculations, we show that these ``visible'' decays cannot be the dominant decay modes of the $\tau$ neutrino.Comment: 8 pgs. LaTeX (1 uuencoded fig., also available on request), Bartol-930XXX, JHU-TIPAC-930026, UM-TH-93-2

Kinematic Enhancement of Non-Perturbative Corrections to Quarkonium Production

In this letter we address issues involved in quarkonium production near the boundaries of phase space. It is shown that higher-order non-perturbative contributions are enhanced in this kinematic region and lead to a breakdown of the non-relativistic (NRQCD) expansion. This breakdown is a consequence of sensitivity to the kinematics of soft gluon radiation and to the difference between partonic and hadronic phase space. We show how these large corrections can be resummed giving the dominant contribution to the cross section. The resummation leads to the introduction of non-perturbative, universal distribution functions. We discuss the importance of these shape functions for several observables, in particular the energy distribution of photo-produced $J/\psi$ close to the endpoint.Comment: Latex 13 page

The structure of flame filaments in chaotic flows

The structure of flame filaments resulting from chaotic mixing within a combustion reaction is considered. The transverse profile of the filaments is investigated numerically and analytically based on a one-dimensional model that represents the effect of stirring as a convergent flow. The dependence of the steady solutions on the Damkohler number and Lewis number is treated in detail. It is found that, below a critical Damkohler number Da(crit), the flame is quenched by the flow. The quenching transition appears as a result of a saddle-node bifurcation where the stable steady filament solution collides with an unstable one. The shape of the steady solutions for the concentration and temperature profiles changes with the Lewis number and the value of Da(crit) increases monotonically with the Lewis number. Properties of the solutions are studied analytically in the limit of large Damkohler number and for small and large Lewis number.Comment: 17 pages, 13 figures, to be published in Physica

Errors in Lattice Extractions of alpha_s Due to Use of Unphysical Pion Masses

We investigate the errors due to the use of unphysical values of light quark masses in lattice extractions of $\alpha_s$. A functional form for the pion mass dependence of the quarkonium mass splittings ($\Delta m$) is given as an expansion in $m_\pi/(4\pi f_\pi)$ and $m_\pi r_B$, where $r_B$ is the quarkonium Bohr radius. We find that, to lowest order,$\Delta m\simeq A+B m_\pi^2$, where the scale of $B$ is given by $f_\pi^2 r_B^3$. To order $m_\pi^4$ there are four unknown coefficients, however, utilizing multipole and operator product expansions, symmetry arguments eliminate one of the four unknowns. Using the central values for the lattice spacings which were extracted using two different, unphysical values for the pion mass, we find that the errors introduced by extrapolating to the physical regime are comparable to the errors quoted due to other sources. Extrapolation to physical values of the pion mass {\it increases} the value of $\alpha_s(M_Z)$, bringing its value closer to the high energy extractions.Comment: Version to appear in PLB, with extended discussion and numbers for intermediate values of the pion mas

RS1 Cosmology as Brane Dynamics in an AdS/Schwarzschild Bulk

We explore various facets of the cosmology of the Randall-Sundrum scenario with two branes by considering the dynamics of the branes moving in a bulk AdS/Schwarzschild geometry. This approach allows us both to understand in more detail and from a different perspective the role of the stabilization of the hierarchy in the brane cosmology, as well as to extend to the situation where the metric contains a horizon. In particular, we explicitly determine how the Goldberger-Wise stabilization mechanism perturbs the background bulk geometry to produce a realistic cosmology.Comment: 9 pages, uses ReVTeX, no figure

Planck Scale Symmetry Breaking and Majoron Physics

Majoron models provide neutrino masses via the spontaneous breaking of a global $U(1)$ symmetry. However, it may be argued that all global symmetries will be explicitly violated by gravitational effects. We show that it is possible to preserve most of the usual features of majoron models by invoking $U(1)_{B-L}$ to be a gauge symmetry and adding a second singlet scalar field. The majoron gets a small model dependent mass. The couplings of majorons to neutrinos may be of ordinary strength or may be made arbitrarily weak. We discuss the cosmological and astrophysical consequences of majoron models in the context of a model dependent majoron mass and neutrino coupling. For an appropriate choice of parameters majorons can play the role of dark matter.Comment: 30 pages, UM-TH-92-3