scholarly journals Wave packets in QFT: Leading order width corrections to decay rates and clock behavior under Lorentz boosts

2021 ◽  
Vol 104 (12) ◽  
Author(s):  
Ariel Edery
Keyword(s):  
Wave Packets ◽  
Decay Rates ◽  
Leading Order ◽  
Lorentz Boosts

Estimating Beta Decay Rates Better for Exotic Nuclei

2021 ◽  
Vol 1 ◽  
Keyword(s):  
Wave Function ◽  
Decay Rate ◽  
Beta Decay ◽  
Coulomb Potential ◽  
Order Approximation ◽  
Decay Rates ◽  
Electron Wave Function ◽  
Heavy Nuclei ◽  
Leading Order ◽  
Electron Wave

Physicists from Japan demonstrate an improved estimation of the beta decay rate in heavy nuclei by considering next-to-leading-order approximation for the electron wave function distorted by the Coulomb potential.

scholarly journals Full next-to-leading-order calculations of Higgs boson decay rates in models with non-minimal scalar sectors

2019 ◽  
Vol 949 ◽  
pp. 114791 ◽  
Author(s):  
Shinya Kanemura ◽  
Mariko Kikuchi ◽  
Kentarou Mawatari ◽  
Kodai Sakurai ◽  
Kei Yagyu
Keyword(s):  
Higgs Boson ◽  
Decay Rates ◽  
Leading Order

PROPAGATION OF SEMICLASSICAL WAVE PACKETS THROUGH AVOIDED EIGENVALUE CROSSINGS IN NONLINEAR SCHRÖDINGER EQUATIONS

2014 ◽  
Vol 15 (2) ◽  
pp. 319-365
Author(s):  
Lysianne Hari
Keyword(s):  
Transition Probabilities ◽  
Semiclassical Limit ◽  
Wave Packets ◽  
Schrodinger Equations ◽  
Time Interval ◽  
Dimensional System ◽  
Schrödinger Equations ◽  
Leading Order ◽  
Avoided Crossing ◽  
Crossing Point

We study the propagation of wave packets for a one-dimensional system of two coupled Schrödinger equations with a cubic nonlinearity, in the semiclassical limit. Couplings are induced by the nonlinearity and by the potential, whose eigenvalues present anavoided crossing: at one given point, the gap between them reduces as the semiclassical parameter becomes smaller. For data which are coherent states polarized along an eigenvector of the potential, we prove that when the wave function propagates through the avoided crossing point there are transitions between the eigenspaces at leading order. We analyze the nonlinear effects, which are noticeable away from the crossing point, but see that in a small time interval around this point the nonlinearity’s role is negligible at leading order, and the transition probabilities can be computed with the linear Landau–Zener formula.

scholarly journals B d,s → $$ \gamma \mathrm{\ell}\overline{\mathrm{\ell}} $$ decay with an energetic photon

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Martin Beneke ◽  
Christoph Bobeth ◽  
Yu-Ming Wang
Keyword(s):  
Invariant Mass ◽  
Branching Fraction ◽  
Form Factors ◽  
Invariant Mass Spectrum ◽  
Decay Rates ◽  
Leading Order ◽  
Cp Asymmetry ◽  
Current Decay ◽  
Power Corrections ◽  
Energetic Photon

Abstract We calculate the differential branching fraction, lepton forward-backward asymmetry and direct CP asymmetry for Bd,s → $$ \gamma \mathrm{\ell}\overline{\mathrm{\ell}} $$ γ ℓ ℓ ¯ decays with an energetic photon. We employ factorization methods, which result in rigorous next-to-leading order predic- tions in the strong coupling at leading power in the large-energy/heavy-quark expansion, together with estimates of power corrections and a resonance parameterization of sub- leading power form factors in the region of small lepton invariant mass q2. The Bd,s → $$ \gamma \mathrm{\ell}\overline{\mathrm{\ell}} $$ γ ℓ ℓ ¯ decay shares features of the charged-current decay Bu → $$ \gamma \mathrm{\ell}{\overline{\nu}}_{\mathrm{\ell}} $$ γ ℓ ν ¯ ℓ ., and the FCNC decays B → $$ {K}^{\left(\ast \right)}\mathrm{\ell}\overline{\mathrm{\ell}} $$ K ∗ ℓ ℓ ¯ . As in the former, the leading-power decay rates can be expressed in terms of the B-meson light-cone distribution amplitude and short-distance factors. However, similar to B →$$ {K}^{\left(\ast \right)}\mathrm{\ell}\overline{\mathrm{\ell}} $$ K ∗ ℓ ℓ ¯ , four-quark and dipole operators contribute to the Bd,s → $$ \gamma \mathrm{\ell}\overline{\mathrm{\ell}} $$ γ ℓ ℓ ¯ decay in an essential way, limiting the calculation to q2 ≲ 6 GeV2 below the charmonium resonances in the lepton invariant mass spectrum. A detailed analysis of the main observables and theoretical uncertainties is presented.

Interferometric (Fourier-Spectroscopic) Measurement of Electron Energy Distributions

1990 ◽  
Vol 48 (2) ◽  
pp. 110-111 ◽  
Author(s):  
F. Hasselbach ◽  
A. Schäfer
Keyword(s):  
Group Velocity ◽  
Wave Packets ◽  
Index Of Refraction ◽  
Electron Wave ◽  
Fringe Contrast ◽  
Faraday Cage ◽  
Optical Index ◽  
Wien Filter ◽  
Coherent Wave ◽  
Electric And Magnetic Fields

Möllenstedt and Wohland proposed in 1980 two methods for measuring the coherence lengths of electron wave packets interferometrically by observing interference fringe contrast in dependence on the longitudinal shift of the wave packets. In both cases an electron beam is split by an electron optical biprism into two coherent wave packets, and subsequently both packets travel part of their way to the interference plane in regions of different electric potential, either in a Faraday cage (Fig. 1a) or in a Wien filter (crossed electric and magnetic fields, Fig. 1b). In the Faraday cage the phase and group velocity of the upper beam (Fig.1a) is retarded or accelerated according to the cage potential. In the Wien filter the group velocity of both beams varies with its excitation while the phase velocity remains unchanged. The phase of the electron wave is not affected at all in the compensated state of the Wien filter since the electron optical index of refraction in this state equals 1 inside and outside of the Wien filter.

Thermal self-action of acoustic wave packets in a liquid

1995 ◽  
Vol 165 (10) ◽  
pp. 1145 ◽  
Author(s):  
F.V. Bunkin ◽  
Gennadii A. Lyakhov ◽  
K.F. Shipilov
Keyword(s):  
Acoustic Wave ◽  
Wave Packets
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