79,137 research outputs found

### Light Front Approach for Strong and Weak Decays of Pentaquarks

Strong and weak decays of pentaquarks are studied in the framework of the
light-front approach.Comment: 3 pages, talk given at the 2004 DPF Meeting, Riverside, CA. Aug
26-31, 200

### Possibly New Charmed Baryon States from $\bar B^0\to p\bar p D^{0}$ Decay

We examine the invariant mass spectrum of $D^{0}p$ in $\bar B^0\to p\bar p
D^{0}$ decay measured by BABAR and find that through the 2-step processes of
$\bar B^0\to {\bf B_c^+}(\to D^{0} p)\bar p$, where ${\bf B_c}$ denotes a
charmed baryon state, some of the peaks can be identified with the established
$\Sigma_c(2800)^+$, $\Lambda_c(2880)^+$ and $\Lambda_c(2940)^+$. Moreover, in
order to account for the measured spectrum, it is necessary to introduce a new
charmed baryon resonance with $(m,\,\Gamma)=(3212\pm 20,\,167\pm 34)$ MeV.Comment: 8 pages, 1 figure, title changed and discussions updated, version
accepted for publication in Phys. Rev.

### Use of active control systems to improve bending and rotor flapping response of a tilt rotor VTOL airplane

The results are summarized of an analytical study of the use of active control systems for the purpose of reducing the root mean square response of wing vertical bending and rotor flapping to atmospheric turbulence for a tilt-rotor VTOL airplane. Only the wing/rotor assembly was considered so that results of a wind tunnel test program would be applicable in a subsequent phase of the research. The capabilities and limitations of simple single feedback configurations were identified, and the most promising multiloop feedback configurations were then investigated. Design parameters were selected so as to minimize either wing bending or rotor flapping response. Within the constraints imposed by practical levels of feedback gains and complexity and by considerations of safety, reduction in response due to turbulence of the order of 30 to 50 percent is predicted using the rotor longitudinal cyclic and a trailing edge wing flap as control effectors

### Implications of Recent $\bar{B}^0\to D^{(*)0}X^0$ Measurements

The recent measurements of the color-suppressed modes $\bar B^0\to
D^{(*)0}\pi^0$ imply non-vanishing relative final-state interaction (FSI)
phases among various $\bar B\to D\pi$ decay amplitudes. Depending on whether or
not FSIs are implemented in the topological quark-diagram amplitudes, two
solutions for the parameters $a_1$ and $a_2$ are extracted from data using
various form-factor models. It is found that $a_2$ is not universal:
$|a_2(D\pi)|= 0.40-0.55$ and $|a_2(D^*\pi)|= 0.25-0.35$ with a relative phase
of order $(50-55)^\circ$ between $a_1$ and $a_2$. If FSIs are not included in
quark-diagram amplitudes from the outset, $a_2^{eff}/a_1^{eff}$ and $a_2^{eff}$
will become smaller. The large value of $|a_2(D\pi)|$ compared to
$|a_2^{eff}(D\pi)|$ or naive expectation implies the importance of
long-distance FSI contributions to color-suppressed internal $W$-emission via
final-state rescatterings of the color-allowed tree amplitude.Comment: 17 pages. The Introduction is substantially revised and the order of
the presentation in Sec. 2 is rearranged. To appear in Phys. Re

### Final stare interaction enhancement effect on the near threshold p\bar p system in B^\pm\to p\bar p \p^\pm decay

We discuss the low-mass enhancement effect in the baryon-antibaryon invariant
mass in three-body baryonic B decays using final state interactions in the
framework of Regge theory. We show that the rescattering between baryonic pair
can reproduce the observed mass spectrum.Comment: 7 pages, 11 figure

### An extension of tribimaximal lepton mixing

Harrison, Perkins and Scott have proposed simple charged lepton and neutrino
mass matrices that lead to the tribimaximal mixing $U_{\rm TBM}$. We consider
in this work an extension of the mass matrices so that the leptonic mixing
matrix becomes $U_{\rm PMNS}=V_L^{\ell\dagger}U_{\rm TBM}W$, where $V_L^\ell$
is a unitary matrix needed to diagonalize the charged lepton mass matrix and
$W$ measures the deviation of the neutrino mixing matrix from the bimaximal
form. Hence, corrections to $U_{\rm TBM}$ arise from both charged lepton and
neutrino sectors. Following our previous work to assume a Qin-Ma-like
parametrization $V_{\rm QM}$ for the charged lepton mixing matrix $V_L^\ell$ in
which the {\it CP}-odd phase is approximately maximal, we study the
phenomenological implications in two different scenarios: $V_L^\ell=V_{\rm
QM}^\dagger$ and $V_L^\ell=V_{\rm QM}$. We find that the latter is more
preferable, though both scenarios are consistent with the data within $3\sigma$
ranges. The predicted reactor neutrino mixing angle $\theta_{13}$ in both
scenarios is consistent with the recent T2K and MINOS data. The leptonic {\it
CP} violation characterized by the Jarlskog invariant $J_{\rm CP}$ is generally
of order $10^{-2}$.Comment: 20 pages and 8 figures, Accepted in Phys.Review

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