Search results for "Functional analysis"

Theoretical study of the Ξ(1620) and Ξ(1690) resonances in Ξc→π+MB decays

2017

Nonleptonic weak decays of ${\mathrm{\ensuremath{\Xi}}}_{c}$ into ${\ensuremath{\pi}}^{+}$ and a meson $(M)$-baryon $(B)$ final state, $MB$, are analyzed from the viewpoint of probing $S=\ensuremath{-}2$ baryon resonances, i.e., $\mathrm{\ensuremath{\Xi}}(1620)$ and $\mathrm{\ensuremath{\Xi}}(1690)$, of which spin-parity and other properties are not well known. We argue that the weak decay of ${\mathrm{\ensuremath{\Xi}}}_{c}$ is dominated by a single quark-line diagram, preferred by the Cabibbo-Kobayashi-Maskawa coefficient, color recombination factor, the diquark correlation, and the kinematical condition. The decay process has an advantage of being free from meson resonances in the ${\ens…

Non-leptonic decays of Charmed mesons into two Pseudoscalars

2015

We examine the role of resonant coupled channel final state interactions (FSI), as well as weak annihilation and exchange contributions in explaining all the two body hadronic $D\rightarrow PP$ decay modes data. In the un-unitarized amplitudes we include modified Wilson coefficients with non-factorizable corrections as parameters. For the hadronic form factors, the z-series expansion method is used to get the $q^2$ dependence. The FSI effects are incorporated via a phenomenological approach with widths of resonances to various channels taken from observations where available, and others as additional parameters to be determined from fits of all the theoretical rates to the measured ones. Ou…

The KK¯π decay of the f1(1285) and its nature as a K*K¯ − cc molecule

2016

We investigate the decay of f1(1285)→πKK¯ with the assumption that the f1(1285) is dynamically generated from the K*K¯+cc interaction. In addition to the tree level diagrams that proceed via f1(1285)→K*K+cc→πKK¯, we take into account also the final state interactions of KK¯→KK¯ and πK → πK. The partial decay width and mass distributions of f1(1285)→πKK¯ are evaluated. We get a value for the partial decay width which, within errors, is in fair agreement with the experimental result. The contribution from the tree level diagrams is dominant, but the final state interactions have effects in the mass distributions. The predicted mass distributions are significantly different from phase space an…

MC Study of the p-state Mean-Field Potts Glass

1999

The p-state mean-field Potts glass with ±J-couplings is studied by Monte Carlo (MC) simulations, both for p = 3 and p = 6 states. At the exactly known glass transition temperature Tc, the moments q( k ) of the spin glass order parameter satisfy for p = 3 a simple scaling behavior, q( k ) \({q^{\left( k \right)}}\alpha {N^{ - k/3}}{\tilde f_k}\left\{ {{N^{1/3}}\left( {1 - T/{T_c}} \right)} \right\},k = 1,2,3,...\). The specific-heat maxima exhibit a similar behavior, c V max α const — N -l/3, while the approach of the maxima positions T max to T c as N → ∞ is non-monotonic. For p = 6 the results are compatible with the expected result of a quite peculiar first-order phase transition. The spe…

Symmetry-induced long-lived excited state inAu6−

2007

We present time-resolved photoelectron spectra in combination with quantum chemical calculations based on time-dependent density functional theory for the study of the long-lived excited state of ${\mathrm{Au}}_{6}^{\ensuremath{-}}$. The experimental spectra indicate an excited state lifetime of at least $90\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$. It is shown that the orbital symmetry of the photoexcited state as well as the planarity of ${\mathrm{Au}}_{6}^{\ensuremath{-}}$ are responsible for the unusual long lifetime. A possible decay mechanism is the fluorescence of a photon which is estimated to take place on a time scale of $730\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$.

Anti-dynamical Casimir effect with an ensemble of qubits

2016

Abstract We consider the interaction between a single cavity mode and N ≫ 1 identical qubits, assuming that any system parameter can be rapidly modulated in situ by external bias. It is shown that, for the qubits initially in the ground states, three photons can be coherently annihilated in the dispersive regime for harmonic modulation with frequency 3 ω 0 − Ω 0 , where ω 0 ( Ω 0 ) is the bare cavity (qubit) frequency. This phenomenon can be called “Anti-dynamical Casimir effect”, since a pair of excitations is destroyed without dissipation due to the external modulation. For the initial vacuum cavity state, three qubit excitations can also be annihilated for the modulation frequency 3 Ω 0 …

Identification of a 6.6μs isomeric state in Ir175

2019

Microscopic black-hole pairs in highly excited states

2001

We consider the quantum mechanics of a system consisting of two identical, Planck-size Schwarzschild black holes revolving around their common center of mass. We find that even in a very highly-excited state such a system has very sharp, discrete energy eigenstates, and the system performs very rapid transitions from a one stationary state to another. For instance, when the system is in the 100th excited state, the life times of the energy eigenstates are of the order of $10^{-30}$ s, and the energies of gravitons released in transitions between nearby states are of the order of $10^{22}$ eV.

ERGODICITY IN RANDOMLY COLLIDING QUBITS

2009

The dynamics of a single qubit randomly colliding with an environment consisting of just two qubits is discussed. It is shown that the system reaches an equilibrium state which coincides with a pure random state of three qubits. Furthermore the time average and the ensemble averages of the quantities used to characterize the approach to equilibrium (purity and tangles) coincide, a signature of ergodic behavior.

Improved search for heavy neutrinos in the decay π→eν

2018

A search for massive neutrinos has been made in the decay π+→e+ν. No evidence was found for extra peaks in the positron energy spectrum indicative of pion decays involving massive neutrinos (π→e+νh). Upper limits (90% C.L.) on the neutrino mixing matrix element |Uei|2 in the neutrino mass region 60–135 MeV/c2 were set and are an order of magnitude improvement over previous results.