Related papers: Shape function in QED and bound muon decays
Due to the potential application of regulating droplet shape by external fields in microfluidic technology and micro devices, it becomes increasingly important to understand the shape formation of a droplet in the presence of an electric…
Owing to the fact that m_c^2 ~ m_b \Lambda_QCD, the endpoint region of the charged lepton energy spectrum in the inclusive decay B -> X_c l \nu_l is affected by the Fermi motion of the initial-state b quark bound in the B meson. This effect…
Hadronic decays of the $\tau$ lepton provide a clean environment to study hadron dynamics in an energy regime dominated by resonances. The interesting information is captured in the spectral functions. Recent results from ALEPH on exclusive…
The kinematics of the decay of a bound proton is governed by the proton spectral function. We evaluate this quantity in 16O using the information from nuclear physics experiments. It also includes a correlated part. The reliability of this…
We calculate the shape of the photon spectrum for $B\rightarrow X_{s}+\gamma$ decay in the presence of a background chromomagnetic field for the case of SU(2) gauge group. The effect of the external field resembles the Zeeman effect - the…
The motion of a deformable active particle in linear shear flow is explored theoretically. Based on symmetry considerations, in two spatial dimensions, we propose coupled nonlinear dynamical equations for the particle position, velocity,…
We present a QCD-based approach to the endpoint region of the lepton spectrum in $\bar B\to X_u\,\ell\,\bar\nu$ decays. We introduce a genuinely nonperturbative form factor, the shape function, which describes the fall-off of the spectrum…
The Brownian motion of a test particle interacting with a quantum scalar field in the presence of a perfectly reflecting boundary is studied in (1 + 1)-dimensional flat spacetime. Particularly, the expressions for dispersions in velocity…
We investigate the change in the decay rate of a muon caused by embedding it in the field of a laser. A previous paper found that the change could be large, as much as an order of magnitude. We find the more intuitive result that the change…
Magnetic excitations are studied in gapped quantum spin systems, for which spontaneous two-magnon decays are allowed by symmetry. Interaction between one- and two-particle states acquires nonanalytic frequency and momentum dependence near…
Theoretical approaches to QED scattering in strong fields typically treat the field as a fixed background with simple spacetime dependence, such as a plane wave. Two major challenges are therefore the inclusion of backreaction (e.g.…
Using mass perturbation theory, we infer the bound-state spectrum of massive QED$_2$ and compute some decay widths of unstable bound states. Further, we discuss scattering processes, where all the resonances and particle production…
In the heavy-quark limit, the decay spectrum for radiative and semileptonic inclusive B-meson decays is determined by a universal structure function, i.e. the shape function. We study the constraints on the bilocal heavy-quark operator for…
In this paper we apply the formalism of Accelerated Quantum Dynamics (AQD) to the radiative stopping of highly relativistic electrons in ice. We compute the acceleration profile of the electron along with its lifetime to decay into a muon.…
A 2D Schrodinger equation with interacting Mobius square potential model is solved using Nikiforov-Uvarov Functional Analysis (NUFA) formalism. The energy spectra and the corresponding wave function for the linearly and exponentially…
Resonant scattering of muonic hydrogen atoms via back decay of molecular complex, a key process in the understanding of epithermal muonic molecular formation, is analyzed. The limitations of the effective rate approximation are discussed…
The width of the neutrino decay into the electron and $W$ boson in a strong external magnetic field is obtained from the imaginary part of the neutrino self-energy. This result corrects the formulae existing in the literature. The mean free…
We present a systematic study of the shape function for inclusive B-meson decays in the heavy-quark limit, which is based on the QCD equations of motion and heavy-quark symmetry, and takes into account the cusp divergence due to radiative…
We investigate the effect of curvature on the behaviour of a quantum particle bound to move on a surface. For the Gaussian bump we derive and discuss the quantum potential which results in the appearance of a bound state for particles with…
The shape influence of decaying thermalized source on various characteristics of multifragmentation as well as its interplay with effects of angular momentum and collective expansion are first studied and the most pertinent variables are…