119302886
Full $\mathcal{O}(\alpha)$ electroweak radiative corrections to $t \bar{t} \gamma$ and $e^-e^+\gamma$ productions at ILC with GRACE-Loop
The full $\mathcal{O}(\alpha)$ electroweak radiative corrections to $t \bar{t} \gamma$ and $e^-e^+\gamma$ productions at the International Linear Collider (ILC) are presented in this paper. The computation is performed with the help of GRACE-Loop system. In the physical results, we discuss on the cross section, electroweak corrections, and the top quark forward-backward asymmetry ($A_{FB}$) which are the function of the center-of-mass energy.
15252744
Precise Numerical Evaluation of the Scalar One-Loop Integrals with the Infrared Divergence
We present a new approach for obtaining very precise integration results for infrared vertex and box diagrams, where the integration is carried out directly without performing any analytic integration of Feynman parameters. Using an appropriate numerical integration routine with an extrapolation method, together with a multi-precision lib rary, we have obtained integration results which agree with the analytic results to 10 digits even for such a very small photon mass as 10 150 GeV in the infrared vertex diagram.
15312798
Monte Carlo Approach to Radiative Corrections in Bhabha Scattering
§ 1. lntroduction It has become a common understanding that detailed theoretical predictions for e+ e- experiments should include the radiative corrections with multi-photon contribu­ tion. A well-known example is the significant modification of the apparent cross section around the Z-boson pole at LEP.ll The study of inclusive processes with multi-photon emission has led some authors to propose several kinds of Monte Carlo generators. 2 l In a pre~ious paper 3 l we have reported a new method for the Monte Carlo generator of multi-photon and have shown some results obtained via a computer progam written for muon pair production in e+ e- annihilation. This is a QED version of the parton shower model which has been studied extensively in QCD. In this paper we generalize this method to the Bhabha scattering by employing essen­ tially the same algorithm as that for muon pair production. It will be convenient to summarize the main features of the algorithm to generate photons. We rely on the technique to sum up all the collinear singularities, which plays an essential role in the parton shower model. 4 J The present model is limited to the leading logarithmic approximation, though there is no difficulty in principle to include the next-to-leading corrections. 5 l This approximation is reasonable as the QED coupling a is very small compared with that in QCD. Another remarkable feature is that the transverse momentum distribution of produced photons is derived correctly once one imposes the four-momentum conservation at each of branching vertices. 4 l This is a consequence of the branching, e±--> e±y, being aprocess of 1--> 2 bodies.
54183358
Calculation of Single Top Quark Production in Electron-Positron Scattering
122500053
A New Treatment of the Scaling Violation for Flavor Singlet Distribution Functions in QCD
In a previous paper (Ref. 1), hereafter, we call I) , Q 2 dependence for the parton distribution functions is extensively studied in the framework of Quantum Chromodynamics (QCD). In the paper I, "kernel function" method (method-2 of I) is proposed to calculate the Q 2 dependent parton distribution functions. This method is intended to obtain the exact solution of Altarelli-Parisi equations. 2 >3> The parton distribution functions f. (x, Q 2) in a hadron are*>
123615884
Automation of loop amplitudes in numerical approach
Abstract An automatic calculating system GRACE-L1 of one-loop Feynman amplitude is reviewed. This system can be applied to 2 to 2-body one-loop processes. A sample calculation of 2 to 3-body one-loop amplitudes is also presented.
116955892
Realisability of SUSY discrete flavour symmetry in our universe
We study the realisation of supersymmetric discrete flavour symmetry models to the thermal history of our universe. We focus on the evolution of the pseudo moduli field among the flavons by taking into account finite temperature corrections. We show that the pseudo moduli flavon dominates the energy density of our universe and this domination makes crucially difficult to realise the flavour symmetry models in our universe. We also discuss possible extensions of the supersymmetric discrete flavour symmetry models which can ensure the consistency of the models with the thermal history of our universe. Finally, we show an extension to realise the thermal inflation by the flavon domination.
118806271
Supersymmetry contributions to CP violations in b→s and b→d transitions taking account of new data
We study the contribution of the gluino-squark mediated flavor changing process for the CP violation in $b\to s$ and $b\to d$ transitions facing on recent experimental data. The mass insertion parameters of squarks are constrained by the branching ratios of $b\to s\gamma $ and $b\to d\gamma $ decays. In addition, the time dependent CP asymmetries of $B^0\to \phi K_S$ and $B^0\to \eta ' K^0$ decays severely restrict the allowed region of the mass insertion parameter for the $b\to s$ transition. By using these constraints with squark and gluino masses of 1.5 TeV, we predict the CP asymmetries of $B_s\to \phi \phi $, $B_s\to \eta '\phi $, and $B^0\to K^0\bar K^0$ decays, as well as the CP asymmetries in $b\to s\gamma $ and $b\to d\gamma $ decays. The CP violation in the $B_s\to \phi \phi$ decay is expected to be large owing to the squark flavor mixing, which will be tested at LHCb soon.
119187180
Microscopic study of tetrahedrally symmetric nuclei by an angular-momentum and parity projection method
We study the properties of the nuclear rotational excitations with hypothetical tetrahedral symmetry by employing the microscopic mean-field and residual-interaction Hamiltonians with angular-momentum and parity projection method; we focus on the deformed nuclei with tetrahedral doubly-closed shell configurations. We find that for pure tetrahedral deformation the obtained excitation patterns satisfy the characteristic features predicted by group-representation theory applied to the tetrahedral symmetry group. We find that a gradual transition from the approximately linear to the characteristic rigid-rotor, parabolic energy-vs.-spin dependence occurs as a function of the tetrahedral deformation parameter. The form of this transition is compared with the similar well-known transition in the case of quadrupole deformation.
118882824
Squark flavor mixing and CP asymmetry of neutral B mesons at LHCb
Abstract The CP violation of the neutral B meson is the important phenomenon to search for the new physics. The like-sign dimuon charge asymmetry observed by the D O Collaboration indicates the CP-violating new physics in the B s – B ¯ s mixing. On the other hand, LHCb observed the CP-violating asymmetry in B s 0 → J / ψ ϕ and B s 0 → J / ψ f 0 ( 980 ) , which is consistent with the SM prediction. However, there is still room for new physics of the CP violation. The CKMfitter has presented the allowed region of the new physics parameters taking account of the LHCb data. Based on these results, we discuss the effect of the squark flavor mixing on the CP violation in the B d and B s mesons. We predict asymmetries in the non-leptonic decays B d 0 → ϕ K S , B d 0 → η ′ K 0 , B s 0 → ϕ ϕ and B s 0 → ϕ η ′ .
122892862
Search for alpha inelastic condensed state in 24Mg
The alpha inelastic scattering from 24Mg was measured to obtain the isoscalar natural-parity excitation strengths and to search for α-condensed states. Multipole decomposition analysis was performed for the measured cross sections, and the strength distributions for the ΔL = 0–3 transitions were successfully obtained. The decay particles from the excited states in 24Mg were also measured in concidence with the inelastically scattered alpha particles. Candidates were found for α-condensed states around the 16O core.