Radiative corrections to semileptonic decays of charged hyperons

We have studied the radiative corrections to the lepton energy spectrum in semileptonic hyperon decays. The calculation is performed relativistically for the baryons as well as for the leptons, under the assumption of the effective current-current interaction of the V-?A type for the baryonic part. We obtain the explicit formula of radiative corrections to the lepton energy spectrum which we can exactly evaluate in case of charged hyperon decays. Numerical values of the radiative corrections to the decays rate and the shape of the lepton energy spectrum are also given for some decay modes. It is shown that the spectral shape is little affected by the radiative corrections.     

Long-Range S-Wave Interactions in Bose-Einstein Condensates: An Exact Correspondence Between Truncated Free Energy and Dynamics

We consider the Gross-Pitaevskii(GP) model of a Bose-Einstein Condensate(BEC) with non-local s-wave interactions. The non-locality is represented by corrections to the local GP equation. Due to such corrections to the GP equation, there arise corrections to the free energy functional as well. We present here a proof of the exact correspondence between the free energy and the dynamics for typical terms appearing while considering corrections to the GP equation at any order. This non-trivial correspondence can be used to study BECs perturbatively while going beyond the Fermi pseudopotential.     

Radiative neutron capture near threshold

The surprisingly large “pair” term corrections to threshold radiative neutron capture, previously calculated by Riska and Brown, and Gari and Huffman, are calculated in a new way in which they appear as relativistic corrections to the impulse approximation arising from the small negative energy components of the wave functions of the two nucleon system. Looking at these corrections from this point of view suggests not only that these small negative energy components are observable in non-relativistic processes, but also that the size of these corrections may ultimately depend on, or give information about, a consistent relativistic treatment of the nuclear force problem.     

Nonperturbative shell correction to the Bethe-Bloch formula for the energy losses of fast charged particles

A simple method including nonperturbative shell corrections has been developed for calculating energy losses on complex atoms. The energy losses of fast highly charged ions on neon, argon, krypton, and xenon atoms have been calculated and compared with experimental data. It has been shown that the inclusion of the non-perturbative shell corrections noticeably improves agreement with experimental data as compared to calculations by the Bethe-Bloch formula with the standard corrections. This undoubtedly helps to reduce the number of fitting parameters in various modifications of the Bethe-Bloch formula, which are usually determined semiempirically.     

Fluctuations in Derrida's random energy and generalized random energy models

The fluctuations of the finite-size corrections to the free energy per site of the random energy model (REM) and the generalized random energy model (GREM) are investigated. Almost sure behavior for the corrections of order (logN)/N is given. We also prove convergence in distribution for the corrections of order 1/N.     

Simulation of prefactor anomalies in superionic conductors in the case of arbitrary energy losses. III. Finite-barrier corrections

In previous publications (Samgin and Ezin, Ionics 14:345?C348, 2008; Samgin and Ezin, Ionics 15:717?C723, 2009), we presented a numerical technique to study the prefactor in the ion diffusion coefficient as a function of the average energy losses of ions to the bath. In the present paper, we model the prefactor in a perturbation theoretical fashion when energy losses are not constant with the ion energy. Using cubic and quartic potentials as examples, we show that including the energy dependence to the energy losses to be converted in finite-barrier corrections may be expected to reduce further the value of the prefactor. We give an extension of the Huberman?CBoyce formula for conductivity prefactors from constant to varying energy losses. The finite-barrier corrections in a protonic conductor are estimated to be of the order of 10?% to a leading-order term in the prefactor expansion. These corrections must be built into an accurate analysis of ion diffusion mechanism.     

NLO QCD corrections to graviton induced deep inelastic scattering

We consider Next-to-Leading-Order QCD corrections to ADD graviton exchange relevant for Deep Inelastic Scattering experiments. We calculate the relevant NLO structure functions by calculating the virtual and real corrections for a set of graviton interaction diagrams, demonstrating the expected cancellation of the UV and IR divergences. We compare the NLO and LO results at the centre-of-mass energy relevant to HERA experiments as well as for the proposed higher energy lepton–proton collider, LHeC, which has a higher fundamental scale reach.     

Quantum corrections from nonresonant WW scattering

An estimate is presented of the leading radiative corrections to low energy electroweak precision measurements from strong nonresonant WW scattering at the TeV energy scale. The estimate is based on a novel representation of nonresonant scattering in terms of the exchange of an effective scalar propagator with simple poles in the complex energy plane. The resulting corrections have the form of the corrections from the standard model Higgs boson with the mass set to the unitarity scale for strong WW scattering.     

Relative to the interpretation of terms of the Schrödinger perturbation theory series

An approach different from those ordinarily expounded is proposed for the construction of the Schrödinger perturbation theory. This approach sets up a functional dependence between the energy corrections and the coefficients characterizing the corrections to the wave functions. It is shown that within the framework of the Schrödinger theory these coefficients are determined by extremum conditions of fourth-order corrections to the energy. In the Schrödinger approximation the fourth-order energy corrections reach their extremal values. The approach developed includes a proof of the Dalgarno and Stewart theorem that says that the energy can be estimated to the order (2n + 1) if the wave function is known to n-th-order accuracy.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 18–20, February, 1982.     

A test of perturbation theory for determining anharmonic vibrational corrections to properties of diatomic molecules

The convergence behaviour of the Rayleigh-Schrödinger perturbation series for obtaining anharmonic vibrational corrections to properties of diatomic molecules is studied. Various procedures for ordering these corrections are examined. It is verified numerically that an asymptotically divergent energy series results when the complete anharmonic potential is taken as the first-order hamiltonian. By contrast, when each term in a Taylor series expansion of the energy about the equilibrium distance is identified with successively higher orders of perturbation, convergence problems are essentially obviated. Properties other than the energy are also investigated with regard to convergence.     

QCD Correction to σ(e+e-→ZH→Zbb)

We study the QCD corrections to the calculated values of σ(e⁺e^-→ZH→Zbb), and find that for M_H<100 GeV, the process can be measured at the LEP energy to extract information of Higgs and the QCD corrections are negligible, namely the tree-level calculation is sufficiently aciurate for the energy range, while for M_H > 100 GeV, the Higgs-involved subprocess can only be investigated at NLC, and then the QCD correction becomes as large as 45%. For M_H > 2mt, considering the subprocess e⁺e^-→ZH→Ztt, the QCD corrections are also important and must be taken into account for the cross section evaluation.     

Replica Method and Finite Volume Corrections

In this note we introduce a method to calculate the finite volume corrections to the mean field results for the free energy when replica symmetry is broken at one-step. We find that the naive results are modified by the presence of additional corrections: these corrections can be interpreted as arising from fluctuations in the size of the blocks in the replica approach. The computation suggests a new approach for deriving the replica broken results in a rigorous way.     

Resummation of angular dependent corrections in spontaneously broken gauge theories

Recent investigations of electroweak radiative corrections have revealed the importance of higher order contributions in high energy processes, where the size of typical corrections can exceed those associated with QCD considerably. Beyond one loop, only universal (angular independent) corrections are known to all orders except for massless processes, where also angle dependent corrections exist in the literature. In this paper we present general arguments for the consistent resummation of angle dependent subleading (SL) logarithmic corrections to all orders in the regime where all invariants are still large compared to the gauge boson masses. We discuss soft isospin correlations, fermion mass and gauge boson mass gap effects, the longitudinal and Higgs boson sector as well as mixing contributions including CKM effects for massive quarks. Two loop results for the right handed Standard Model are generalized in the context of the high energy effective theory based on the standard model Lagrangian in the symmetric basis with the appropriate matching conditions to include the soft QED regime. The result is expressed in exponentiated operator form in a CKM extended isospin space in the symmetric basis. Thus, a full electroweak SL treatment based on the infrared evolution equation method is formulated for arbitrary high energy processes at future colliders. Comparisons with known results are presented. Received: 12 February 2002 / Revised version: 7 March 2002 / Published online: 8 May 2002     

Heavy quarks in the presence of higher derivative corrections from AdS/CFT

We use the gauge–string duality to study heavy quarks in the presence of higher derivative corrections. These corrections correspond to the finite-coupling corrections on the properties of heavy quarks in a hot plasma. In particular, we study the effects of these corrections on the energy loss and the dissociation length of a quark–antiquark pair. We show that the calculated energy loss of heavy quarks through the plasma increases. We also find in general that the dissociation length becomes shorter with the increase of coupling parameters of higher curvature terms.     

原子核体积和质量效应对较轻元素及同位素类氢离子能级的修正

在类氢离子电子束缚能一级相对论修正的基础上,计算了原子核的体积效应及质量效应对较轻元素及同位素类氢离子能级的修正量,结果显示,原子核的体积及质量效应不仅导致同位异核氢及类氢离子精细结构能级出现分裂,还会导致类氢离子精细结构能级的简并消失。     

On the possibility of dark energy from corrections to the Wheeler–DeWitt equation

We present a method for approximating the effective consequence of generic quantum gravity corrections to the Wheeler–DeWitt equation. We show that in many cases these corrections can produce departures from classical physics at large scales and that this behaviour can be interpreted as additional matter components. This opens up the possibility that dark energy (and possible dark matter) could be large scale manifestations of quantum gravity corrections to classical general relativity. As a specific example we examine the first order corrections to the Wheeler–DeWitt equation arising from loop quantum cosmology in the absence of lattice refinement and show how the ultimate breakdown in large scale physics occurs.     

Negative energy correction for nuclear polarization in muonic atoms

Negative energy corrections to the conventional calculations of nuclear polarization effects in muonic atoms are calculated. It is shown that the corrections are negligible as far as the NP effects due to low lying nuclear states and states in the giant resonance regions are concerned. However, the formula used for the muonic NP calculations breaks down if nuclear excitations with larger energies than the muonic mass are considered. This means that the method cannot be used for calculations of NP effects in electronic atoms. This revised version was published online in August 2006 with corrections to the Cover Date.     

Corrections to the wave function and the hyperfine structure in exotic atoms

We present an analytical evaluation of radiative corrections in exotic atoms induced by the one-loop electronic vacuum polarization. We evaluate corrections to the energy levels, to the wave function (at the origin) and to the hyperfine structure. We treat all corrections analytically within a non-relativistic approximation. Agreement is found with a few available numerical results. The analytical treatment allows to determine the asymptotic forms of the corrections in the limit of a small atomic radius, which for the atomic systems considered corresponds to a large mass of the constituent particle as compared to the electron mass. The asymptotics can be verified using the effective charge approach. Received: 28 January 1998 / Accepted: 13 March 1998     

A modified Balitsky–Kovchegov equation

We propose a modified version of the Balitsky–Kovchegov (BK) evolution equation, which includes the main NLO corrections. We use the result that the main NLO corrections to the BFKL kernel are the LO DGLAP corrections. We present a numerical solution of the modified non-linear equation, and compare with the solution of the unmodified BK equation. We show that the saturation momentum has a sharp increase in the LHC energy range. Our numerical solution indicates that the influence of the preasymptotic corrections, related to the full anomalous dimensions of the DGLAP equation, are rather large. These corrections moderate the energy behavior of the amplitude, as well as the value of the saturation scale. All our calculations are made with a fixed value of _S.     

Meson exchange corrections and properties of nuclear matter and neutron matter

A calculation of meson exchange corrections to the binding energy as function of the density is presented for nuclear matter and neutron matter. The framework is the application of non-covariant perturbation theory to a field theoretical Hamiltonian. Within a Brueckner-type approximation we restrict ourselves to the calculation of those meson exchange corrections which are due to one meson exchange and which produce no mass renormalization corrections. The results are reported in detail and the structure of the results is revealed. As a net effect, we find that our meson exchange corrections give a repulsion in nuclear matter yielding about 5 MeV less binding at the saturation point. For neutron matter, the effects are very small.