Search results for "Hamiltonian"
showing 10 items of 662 documents
CP, T and CPT versus temporal asymmetries for entangled states of the B-system
1999
The observables used in the K-system to characterize T and CPT violation are no longer useful for the Bd-system, since the width difference between the physical states is vanishingly small. We show that only Im(epsilon) and Re(delta) can survive if Delta Gamma=0, and build alternative CP-odd, CPT-odd, T-odd and temporal asymmetries for the (B_CP -> B0, B0bar) transitions. These quantities enable us to test T and CPT invariances of the effective Hamiltonian for the B-system. The method needs the CP eigenstates B_CP, which can be tagged unambiguously to order lambda^3 from the entangled states of a B-factory.
Indirect CP violation in the B-system
1997
We show that, contrary to the flavour mixing amplitude q/p, both Re(epsilon) and Im(epsilon) are observable quantities, where epsilon is the phase- convention-independent CP mixing. We consider semileptonic B_d decays from a CP tag and build appropriate time-dependent asymmetries to separate out Re(epsilon) and Im(epsilon). "Indirect" CP violation would have in Im(epsilon)/(1+|epsilon|^2) its most prominent manifestation in the B-system, with expected values in the standard model ranging from -0.37 to -0.18. This quantity is controlled by a new observable phase: the relative one between the CP-violating and CP-conserving parts of the effective hamiltonian. For time-integrated rates we point…
Running soft parameters in SUSY models with multiple U(1) gauge factors
2012
Abstract We generalize the two-loop renormalization group equations for the parameters of the softly broken SUSY gauge theories given in the literature to the most general case when the gauge group contains more than a single Abelian gauge factor. The complete method is illustrated at two-loop within a specific example and compared to some of the previously proposed partial treatments.
Systematic study of neutrinoless double beta decay to excited 0+ states
2003
Abstract A systematic study of neutrinoless double beta (0 νββ ) decay to excited 0 + states, described as monopole-vibrational states or as composed of two collective quadrupole-phonon states, has been performed. Both double β − and double β + /EC decays have been analyzed within the framework of the multiple commutator model (MCM) by using a realistic nuclear many-body Hamiltonian and realistic mean-field single-particle bases. It is found that the associated 0 νββ -decay transitions are suppressed relative to the decay to the final ground state both by the available phase space and especially by the smallness of the involved transition matrix elements. For completeness, also the double β…
A consistent study of the the low energy baryon spectrum and the nucleon-nucleon interaction within the chiral quark model
1995
By solving the Schr\"{o}dinger equation for the three-quark system in the hyperspherical harmonic approach, we have studied the low energy part of the nucleon and $\Delta$ spectra using a quark-quark interaction which reproduces the nucleon-nucleon phenomenology. The quark-quark hamiltonian considered includes, besides the usual one-gluon exchange, pion and sigma exchanges generated by the chiral symmetry breaking. The baryonic spectrum obtained is reasonable and the resulting wave function gives consistency to the ansatz used in the two baryon system.
Spin-dependent potentials from lattice QCD
2006
The spin-dependent corrections to the static inter-quark potential are phenomenologically relevant to describing the fine and hyperfine spin splitting of the heavy quarkonium spectra. We investigate these corrections, which are represented as the field strength correlators on the quark-antiquark source, in SU(3) lattice gauge theory. We use the Polyakov loop correlation function as the quark-antiquark source, and by employing the multi-level algorithm, we obtain remarkably clean signals for these corrections up to intermediate distances of around 0.6 fm. Our observation suggests several new features of the corrections.
Relations between the Hepp-Lieb and the Alli-Sewell Laser Models
2009
In this paper we show that the dissipative version of the laser model proposed by Alli and Sewell can be obtained by considering the stochastic limit of the (open system) hamiltonian introduced by Hepp and Lieb in their seminal work. We also prove that the Dicke-Haken-Lax hamiltonian produces, after the stochastic limit is considered, the generator of a semigroup with equations of motion very similar to those of Alli-Sewell, and coinciding with these under suitable conditions.
SEMICLASSICAL DESCRIPTION OF SPIN EXCITATIONS OF THE PARTICLE-CORE INTERACTION SYSTEM
1993
A model Hamiltonian describing a nucleon moving in a shifted oscillator well and inter-acting with a harmonic core through a quadrupole-quadrupole term is semiclassically treated. The solutions of the linearised equations of motion are quantised by the Bohr-Sommerfeld procedure. Among the four RPA modes, there is one which corresponds to the harmonic vibration of the spin degree of freedom. This mode is analogous to the spin wave mode describing a system of interacting spins placed in a magnetic field. The state describes a harmonic wobbling motion around a stationary state belonging to the ground rotational band.
On the hamiltonian approach to commutator anomalies in (3+1) dimensions
1990
Abstract The quantization of Weyl fermions in the presence of an external nonabelian vector potential is discussed in the case of spacetime dimension (3+1). The hamiltonian approach is used, in the temporal gauge A 0 = 0. In particular, it is explicitly shown how one can lift the action of (an extension of) the group of gauge transformations to the bundle of Fock spaces parametrized by smooth vector potentials.
Determination of the ΔS=1 weak Hamiltonian of the SU(4) chiral limit through topological zero-mode wave functions
2008
38 pages, 9 figures.-- Published in: JHEP05(2008)043, available at: http://dx.doi.org/10.1088/1126-6708/2008/05/043 (open-acess).