Flavor Oscillations from a Spatially Localized Source: A Simple General Treatment

A unique description avoiding confusion is presented for all flavor oscillation experiments in which particles of a definite flavor are emitted from a localized source. The probability for finding a particle with the wrong flavor must vanish at the position of the source for all times. This condition requires flavor-time and flavor-energy factorizations which determine uniquely the flavor mixture observed at a detector in the oscillation region; i.e. where the overlaps between the wave packets for different mass eigenstates are almost complete. Oscillation periods calculated for ``gedanken'' time-measurement experiments are shown to give the correct measured oscillation wave length in space when multiplied by the group velocity. Examples of neutrinos propagation in a weak field and in a gravitational field are given. In these cases the relative phase is modified differently for measurements in space and time. Energy-momentum (frequency-wave number) and space-time descriptions are complementary, equally valid and give the same results. The two identical phase shifts obtained describe the same physics; adding them together to get a factor of two is double counting.Comment: 20 pages, revtex, no figure

Transversal inhomogeneities in dilute vibrofluidized granular fluids

The spontaneous symmetry breaking taking place in the direction perpendicular to the energy flux in a dilute vibrofluidized granular system is investigated, using both a hydrodynamic description and simulation methods. The latter include molecular dynamics and direct Monte Carlo simulation of the Boltzmann equation. A marginal stability analysis of the hydrodynamic equations, carried out in the WKB approximation, is shown to be in good agreement with the simulation results. The shape of the hydrodynamic profiles beyond the bifurcation is discussed

Appraising the Effectiveness of a Simple Evaluational Approach to Problems of Retardation and Behavior in Childhood

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67035/2/10.1177_000992287201100921.pd

Charmless B→PPB \to PP decays using flavor SU(3) symmetry

The decays of $B$ mesons to a pair of charmless pseudoscalar ($P$) mesons are analyzed within a framework of flavor SU(3). Symmetry breaking is taken into account in tree ($T$) amplitudes through ratios of decay constants; exact SU(3) is assumed elsewhere. Acceptable fits to $B \to \pi \pi$ and $B \to K \pi$ branching ratios and CP asymmetries are obtained with tree, color-suppressed ($C$), penguin ($P$), and electroweak penguin ($P_{EW}$) amplitudes. Crucial additional terms for describing processes involving $\eta$ and $\eta'$ include a large flavor-singlet penguin amplitude ($S$) as proposed earlier and a penguin amplitude $P_{tu}$ associated with intermediate $t$ and $u$ quarks. For the $B^+ \to \pi^+ \eta'$ mode a term $S_{tu}$ associated with intermediate $t$ and $u$ quarks also may be needed. Values of the weak phase $\gamma$ are obtained consistent with an earlier analysis of $B \to VP$ decays, where $V$ denotes a vector meson, and with other analyses of CKM parameters.Comment: 26 pages, 1 figure. To be submitted to Phys. Rev. D. Reference update

Measuring the Relative Strong Phase in D0→K∗+K−D^0 \to K^{*+} K^- and D0→K∗−K+D^0 \to K^{*-} K^+ Decays

In a recently suggested method for measuring the weak phase $\gamma$ in $B^\pm \to K^\pm (KK^*)_D$ decays, the relative strong phase $\delta_D$ in $D^0 \to K^{*+} K^-$ and $D^0 \to K^{*-} K^+$ decays (equivalently, in $D^0 \to K^{*+} K^-$ and \od \to K^{*+} K^-) plays a role. It is shown how a study of the Dalitz plot in $D^0 \to K^+ K^- \pi^0$ can yield information on this phase, and the size of the data sample which would give a useful measurement is estimated.Comment: 13 pages, latex, 5 figures, submitted to Phys. Rev. D. Appendix and some text on additional resonant contributions adde

The relevance of model-driven engineering thirty years from now

International audienceAlthough model-driven engineering (MDE) is now an established approach for developing complex software systems, it has not been universally adopted by the software industry. In order to better understand the reasons for this, as well as to identify future opportunities for MDE, we carried out a week-long design thinking experiment with 15 MDE experts. Participants were facilitated to identify the biggest problems with current MDE technologies, to identify grand challenges for society in the near future, and to identify ways that MDE could help to address these challenges. The outcome is a reflection of the current strengths of MDE, an outlook of the most pressing challenges for society at large over the next three decades, and an analysis of key future MDE research opportunities

Rescattering and chiral dynamics in B\to \rho\pi decay

We examine the role of B^0(\bar B^0) \to \sigma \pi^0 \to \pi^+\pi^- \pi^0 decay in the Dalitz plot analysis of B^0 (\bar B^0) \to \rho\pi \to \pi^+\pi^-\pi^0 decays, employed to extract the CKM parameter \alpha. The \sigma \pi channel is significant because it can break the relationship between the penguin contributions in B\to\rho^0\pi^0, B\to\rho^+\pi^-, and B\to\rho^-\pi^+ decays consequent to an assumption of isospin symmetry. Its presence thus mimics the effect of isospin violation. The \sigma\pi^0 state is of definite CP, however; we demonstrate that the B\to\rho\pi analysis can be generalized to include this channel without difficulty. The \sigma or f_0(400-1200) ``meson'' is a broad I=J=0 enhancement driven by strong \pi\pi rescattering; a suitable scalar form factor is constrained by the chiral dynamics of low-energy hadron-hadron interactions - it is rather different from the relativistic Breit-Wigner form adopted in earlier B\to\sigma\pi and D\to\sigma\pi analyses. We show that the use of this scalar form factor leads to an improved theoretical understanding of the measured ratio Br(\bar B^0 \to \rho^\mp \pi^\pm) / Br(B^-\to \rho^0 \pi^-).Comment: 26 pages, 8 figs, published version. typos fixed, minor change

Measurement of CP asymmetry in Cabibbo suppressed D0 decays

We measure the CP-violating asymmetries in decays to the D0 -> K+K- and D0 -> pi+pi- CP eigenstates using 540 fb^{-1} of data collected with the Belle detector at or near the Upsilon(4S) resonance. Cabibbo-favored D0 -> K-pi+ decays are used to correct for systematic detector effects. The results, A_{CP}^{KK} = (-0.43 +- 0.30 +- 0.11)% and A_{CP}^{pipi} = (+0.43 +- 0.52 +- 0.12)%, are consistent with no CP violation.Comment: Submitted to Phys. Lett.

Two-Body Charmless B Decays Involving eta and eta'

We discuss implications of recent experimental data for B decays into two pseudoscalar mesons, with emphasis on those with $\eta$ and $\eta'$ in the final states. Applying a U-spin argument, we show that tree and penguin amplitudes, both in $B^+ \to \pi^+ \eta$ and in $B^+ \to \pi^+ \eta'$, are of comparable magnitudes. Nontrivial relative weak and strong phases between the tree-level amplitudes and penguin-loop amplitudes in the $B^{\pm} \to \pi^{\pm} \eta$ modes are extracted. We predict possible values for the averaged branching ratio and CP asymmetry of the $B^{\pm} \to \pi^{\pm} \eta'$ modes. We test the assumption of a singlet-penguin amplitude with the same weak and strong phases as the QCD penguin in explaining the large branching ratios of $\eta' K$ modes, and show that it is consistent with current branching ratio and CP asymmetry data of the $B^+ \to (\pi^0, \eta, \eta') K^+$ modes. We also show that the strong phases of the singlet-penguin and tree-level amplitudes can be extracted with further input of electroweak penguin contributions and a sufficiently well-known branching ratio of the $\eta K^+$ mode. Using SU(3) flavor symmetry, we also estimate required data samples to detect modes that have not yet been seen.Comment: 16 pages, 7 figures, to be submitted to Phys. Rev. D (v1); some remarks and references added (v2); more references added (v3

Effects of cleaning methods upon preservation of stable isotopes and trace elements in shells of Cyprideis torosa (Crustacea, Ostracoda): implications for palaeoenvironmental reconstruction

The trace element (Sr/Ca and Mg/Ca) and stable isotope (δ¹⁸O and δ¹³C) geochemistry of fossil ostracod valves provide valuable information, particularly in lacustrine settings, on palaeo-water composition and palaeotemperature. The removal of sedimentary and organic contamination prior to geochemical analysis is essential to avoid bias of the results. Previous stable isotope and trace element work on ostracod shells has, however, employed different treatments for the removal of contamination beyond simple ‘manual’ cleaning using a paint brush and methanol under a low-power binocular microscope. For isotopic work pre-treatments include chemical oxidation, vacuum roasting and plasma ashing, and for trace element work sonication, chemical oxidation and reductive cleaning. The impact of different treatments on the geochemical composition of the valve calcite has not been evaluated in full, and a universal protocol has not been established. Here, a systematic investigation of the cleaning methods is undertaken using specimens of the ubiquitous euryhaline species, Cyprideis torosa. Cleaning methods are evaluated by undertaking paired analyses on a single carapace (comprising two valves); in modern ostracods, whose valves are assumed to be unaltered, the two valves should have identical geochemical and isotopic composition. Hence, when one valve is subjected to the chosen treatment and the other to simple manual cleaning any difference in composition can confidently be assigned to the treatment method. We show that certain cleaning methods have the potential to cause alteration to the geochemical signal, particularly Mg/Ca and δ¹⁸O, and hence have implications for palaeoenvironmental reconstructions. For trace element determinations we recommend cleaning by sonication and for stable isotope analysis, oxidation by hydrogen peroxide. These methods remove contamination, yet do not significantly alter the geochemical signal