Search results for "INTERFERENCE"
showing 10 items of 573 documents
Model-independent confirmation of theZ(4430)−state
2015
The decay $B^0\to \psi(2S) K^+\pi^-$ is analyzed using $\rm 3~fb^{-1}$ of $pp$ collision data collected with the LHCb detector. A model-independent description of the $\psi(2S) \pi$ mass spectrum is obtained, using as input the $K\pi$ mass spectrum and angular distribution derived directly from data, without requiring a theoretical description of resonance shapes or their interference. The hypothesis that the $\psi(2S)\pi$ mass spectrum can be described in terms of $K\pi$ reflections alone is rejected with more than 8$\sigma$ significance. This provides confirmation, in a model-independent way, of the need for an additional resonant component in the mass region of the $Z(4430)^-$ exotic sta…
Jet substructure measurements of interference in non-interfering SMEFT effects
2019
The tails of diboson production at the LHC are sensitive to the interference between Standard Model and higher dimension operators parameterizing the effects of heavy new physics. However, helicity selection rules for the diboson scattering amplitudes set an obstruction to the na\"ive interference contributions of dimension six operators, causing the total diboson rate correction's leading contribution to cancel. In this case, carefully measuring the azimuthal decay angles "resurrects" the interference, recouping sensitivity to the "non-interfering" operators. We explore these signatures in detail, and find that the EFT uncertainties associated with higher-dimensional operators are uniquely…
The role of Delta(1700) excitation and rho production in double pion photoproduction
2001
Recent information on invariant mass distributions of the $\gamma p\to\pi^+\pi^0 n$ reaction, where previous theoretical models had shown deficiencies, have made more evident the need for new mechanisms, so far neglected or inaccurately included. We have updated a previous model to include new necessary mechanisms. We find that the production of the $\rho$ meson, and the $\Delta(1700)$ excitation, through interference with the dominant terms, are important mechanisms that solve the puzzle of the $\gamma p\to\pi^+\pi^0 n$ reaction without spoiling the early agreement with the $\gamma p\to\pi^+\pi^- p$ and $\gamma p\to\pi^0\pi^0 p$ reactions.
Resonant detection and production of axions with atoms
2018
The axions and axion-like particles can be detected via a resonant atomic or molecular transition induced by axion absorption. The signal obtained in this process is second order in the axion-electron interaction constant and hence small. In this chapter, it is demonstrated that this signal may become first order in the axion-electron interaction constant if we allow the interference between the axion-induced transition amplitude and the transition amplitude induced by the electromagnetic radiation. Additionally, we show that the conventional scheme of producing axions from photons in a magnetic field may be improved if the field is replaced by an atomic medium in which photons scattering …
Perturbative analysis of the 2νββ decays of 100Mo and 116Cd
2003
We have performed a theoretical analysis of the ground-state-to-ground-state transitions in 100Mo and 116Cd, based on the quasiparticle random-phase approximation and on a straightforward perturbative scheme. The results show that the single-state dominance found in the realistic calculations of the nuclear matrix elements, which is consistent with data, can be viewed as a result of the interference between few two-quasiparticle configurations.
Control of multiphoton radiative recombination through the action of two low-frequency fields
2004
Interference effects caused by the simultaneous action of a two low frequency fields with commensurate frequencies during laser assisted radiative recombination (LARR) are investigated theoretically. Varying the relative phase of the two fields the following LARR features may be controlled: a) location of the maxima in the total emitted power; b) enhancement of the total emitted power; c) polar shape of the differential emitted power; d) shape of the emitted power spectra.
Acousto-optical multiple interference switches
2007
The authors introduce an alternative approach for acousto-optical light control based on the interference of light propagating through several waveguides, each subjected to a periodic refractive index modulation induced by a surface acoustic wave. The feasibility of the concept is demonstrated by the realization of an optical switch for arbitrary time intervals with an on/off contrast ratio of 20.
Propagating quantum walks: The origin of interference structures
2003
We analyze the solution of the coined quantum walk on a line. First, we derive the full solution, for arbitrary unitary transformations, by using a new approach based on the four "walk fields" which we show determine the dynamics. The particular way of deriving the solution allows a rigorous derivation of a long wavelength approximation. This long wavelength approximation is useful as it provides an approximate analytical expression that captures the basics of the quantum walk and allows us to gain insight into the physics of the process.
The non dissipative damping of the Rabi oscillations as a "which-path" information
2005
Rabi oscillations may be viewed as an interference phenomenon due to a coherent superposition of different quantum paths, like in the Young's two-slit experiment. The inclusion of the atomic external variables causes a non dissipative damping of the Rabi oscillations. More generally, the atomic translational dynamics induces damping in the correlation functions which describe non classical behaviors of the field and internal atomic variables, leading to the separability of these two subsystems. We discuss on the possibility of interpreting this intrinsic decoherence as a "which-way" information effect and we apply to this case a quantitative analysis of the complementarity relation as intro…
Quantum erasure within the optical Stern-Gerlach model
2005
In the optical Stern-Gerlach effect the two branches in which the incoming atomic packet splits up can display interference pattern outside the cavity when a field measurement is made which erases the which-way information on the quantum paths the system can follow. On the contrary, the mere possibility to acquire this information causes a decoherence effect which cancels out the interference pattern. A phase space analysis is also carried out to investigate on the negativity of the Wigner function and on the connection between its covariance matrix and the distinguishability of the quantum paths.