Search results for "Matrix"
showing 10 items of 3205 documents
Study of decay dynamics andCPasymmetry inD+→KL0e+νedecay
2015
Using 2.92 fb(-1) of electron-positron annihilation data collected at root s = 3.773 GeV with the BESIII detector, we obtain the first measurements of the absolute branching fraction B(D+ -> K(L)(0)e(+)nu(e)) = (4.481 +/- 0.027(stat) +/- 0.103(sys))% and the CP asymmetry A(CP)(D+-> KL0e+nu e) = (-0.59 +/- 0.60(stat) +/- 1.48(sys))%. From the D+ -> K(L)(0)e(+)nu(e) differential decay rate distribution, the product of the hadronic form factor and the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element, f(+)(K)(0)vertical bar V-cs vertical bar, is determined to be 0.728 +/- 0.006(stat) +/- 0.011(sys). Using vertical bar V-cs vertical bar from the SM constrained fit with the measured f(+)…
η–η′ mixing in the flavor basis and large N
2010
Abstract The mass matrix for η – η ′ is derived in the flavor basis at O ( p 4 ) of the chiral Lagrangian using the large N approximation. Under certain assumptions, the mixing angle ϕ = 41.4 ° and the decay constants ratio f K / f π = 1.15 are calculated in agreement with the data. It appears that the FKS scheme arises as a special limit of the chiral Lagrangian. Their mass matrix is obtained without the hypothesis on the mixing pattern of the decay constants.
Meson resonances, large N_c and chiral symmetry
2003
14 páginas, 2 tablas.-- arXiv:hep-ph/0305311v1
Parity nonconservation in the γ decay of polarized17/2−isomers inTc93
2005
The determination of the ${0}^{\ifmmode^\circ\else\textdegree\fi{}}\ensuremath{-}{180}^{\ifmmode^\circ\else\textdegree\fi{}}$ asymmetry (${A}_{\ensuremath{\gamma}}$), which arises because of the parity nonconserving matrix element, in the 751-keV \ensuremath{\gamma} decay of polarized $17/{2}^{\ensuremath{-}}$ isomers in $^{93}\mathrm{Tc}$ with respect to the direction of polarization is reported. A combined analysis of the present results together with those from our earlier work yields an effect of two standard deviations.
Double-beta decay Q values of 116Cd and 130Te
2011
Abstract The Q values of the 116Cd and 130Te double-beta decaying nuclei were determined by using a Penning trap mass spectrometer. The new atomic mass difference between 116Cd and 116Sn of 2813.50(13) keV differs by 4.5 keV and is 30 times more precise than the previous value of 2809(4) keV. The new value for 130Te, 2526.97(23) keV is close to the Canadian Penning trap value of 2527.01 ± 0.32 keV (Scielzo et al., 2009) [1] , but differs from the Florida State University trap value of 2527.518 ± 0.013 keV (Redshaw et al., 2009) [2] by 0.55 keV (2σ). These values are sufficiently precise for ongoing neutrinoless double-beta decay searches in 116Cd and 130Te. Hence, our Q values were used to …
New approach for numerical solution of configuration-space Faddeev equations
1996
A new computational scheme for solving the bound state configuration-space Faddeev equations is applied. The scheme is based on the spline-approximation and the adiabatic limit of Faddeev equations. An ordering of variables being in agreement with the limit was chosen. As a result the matrix of the eigenvalue problem has a sparse block structure. Calculations of the bound states of µpp, µdd, µtt mesic molecules and ¯pdd, ¯ptt antiprotonic ones, were performed. To check the method, calculations of the binding energies for such systems as the positronium ion Ps−,3H and3He were carried out. The results are compared with the best results of other authors.
Two-neutrino ββ decay to excited states. The 0+ → 2+ decay of 136Xe
1993
Abstract A method to calculate the two-neutrino double beta decay (2vββ) to one-phonon excited states is presented. The formalism, which is based on the quasiparticle random phase approximation, is applied to the description of the 2vββ transition 136Xe (0 g.e. + ) → 136 Ba (2 1 + ). It is shown that the participant matrix element is not suppressed by the inclusion of renormalized particle-particle interactions.
Nuclear matrix elements of ββ decay from β-decay data
2005
Abstract The evaluation of the nuclear matrix elements (NME) of the two-neutrino double beta ( 2 ν β β ) decay and neutrinoless double beta ( 0 ν β β ) decay using the proton–neutron quasiparticle random-phase approximation (pnQRPA) is addressed. In particular, the extraction of a proper value of the proton–neutron particle–particle interaction parameter, g pp , of this theory is analyzed in detail. Evidence is shown, that it can be misleading to use the experimental half-life of the 2 ν β β decay to extract a value for g pp . Rather, arguments are given in favour of using the available data on single beta decay for this purpose.
Test of the proton-neutron random-phase approximation method within an extended Lipkin-type model
2001
An extended Lipkin-Meshkov-Glick model for testing the proton-neutron random-phase approximation $(pn\mathrm{RPA})$ method is developed, taking into account explicitly proton and neutron degrees of freedom. Besides the proton and neutron single-particle terms two types of residual proton-neutron interactions, one simulating a particle-particle and the other a particle-hole interaction, are included in the model Hamiltonian so that the model is exactly solvable in an isospin $\mathrm{SU}(2)\ensuremath{\bigotimes}\mathrm{SU}(2)$ basis. The behavior of the first excited (collective) state obtained by (i) exact diagonalization of the Hamiltonian matrix and (ii) with the $\mathrm{pn}\mathrm{RPA}…
Coulomb excitation of $^{78}$Kr
2006
Expérience à JYFL cyclotron (Jyväskylä, Finlande); The Kr isotopes are considered to be among the best cases for shape coexistence studies in the mass A$\sim$70 region. Our campaign to investigate in detail the development of the shape coexistence in the neutron deficient Kr isotopes was started with the stable nucleus $^{78}$Kr. To obtain the information about the intrinsic shape, Coulomb excitation experiments were performed. A total of 26 matrix elements were determined for $^{78)$Kr. Simple geometrical and algebraic models do not reproduce all details of the electromagnetic structure. A good interpretation of the complex structure of the nucleus with competing oblate and prolate shapes …