WEAK PHASES FROM AMPLITUDE PARAMETRIZATION

2005 ◽  
Vol 20 (15) ◽  
pp. 3566-3568
Author(s):  
YEO-YIE CHARNG
Keyword(s):  
Experimental Data ◽  
Theoretical Uncertainty ◽  
Unitarity Triangle ◽  
Tree Amplitude ◽  
Wolfenstein Parameter

We determine the weak phases and the amplitudes by proposing an parametrization to each topologies of amplitudes in power of Wolfenstein parameter λ ~ 0.22. Comparing this parametrization with the experimental data, we can obtain the phase ϕ3 from the B → Kπ data up to theoretical uncertainty of O(λ3) ~ 5%. We find that these solutions indicate a large color-suppressed tree amplitude. The extraction of the phase ϕ2 and ϕ3 are consistent with the global unitarity triangle fit.

IS THERE ANY PUZZLE OF NEW PHYSICS IN B → Kπ DECAYS?

2008 ◽  
Vol 23 (21) ◽  
pp. 3296-3299 ◽  
Author(s):  
C. S. KIM ◽  
SECHUL OH ◽  
YEO WOONG YOON
Keyword(s):  
Experimental Data ◽  
Standard Model ◽  
New Physics ◽  
The Other ◽  
Tree Amplitude ◽  
Systematic Method ◽  
Cp Asymmetry ◽  
Strong Phase ◽  
Weak Phase ◽  
Hadronic Parameter

Due to re-parametrization invariance of decay amplitudes, any single new physics (NP) amplitude arising through either the electro-weak penguin (EWP) or the color-suppressed tree amplitude can be embedded simultaneously into both the color-suppressed tree and the EWP contribution in B → Kπ decays. We present a systematic method to extract each standard model (SM)-like hadronic parameter as well as new physics parameters in analytic way, so that one can pinpoint them once experimental data are given. Using the currently available experimental data for B → Kπ modes, we find two possible analytic results: one showing the large SM-like color-suppressed tree contribution and the other showing the large SM-like EWP contribution. The magnitude of the NP amplitude and its weak phase are quite large. For instance, we find |PNP/P′| = 0.39 ± 0.13, φNP = 92° ± 15° and δNP = 7° ± 26°, which are the ratio of the NP-to-SM contribution, the weak and the strong phase of the NP amplitude, respectively. We also investigate the dependence of the NP contribution on the weak phase γ and the mixing induced CP asymmetry of B0 → KSπ0, respectively

scholarly journals IMPROVEMENT OF RENORMALIZATION-SCALE UNCERTAINTIES WITHIN EMPIRICAL DETERMINATIONS OF THE b-QUARK MASS

2006 ◽  
Vol 15 (03) ◽  
pp. 571-594
Author(s):  
M. R. AHMADY ◽  
V. ELIAS ◽  
A. SQUIRES ◽  
T. G. STEELE ◽  
AILIN ZHANG
Keyword(s):  
Experimental Data ◽  
Cross Section ◽  
Quark Mass ◽  
Scale Dependence ◽  
Theoretical Uncertainty ◽  
Experimental Uncertainty ◽  
Pole Mass ◽  
Renormalization Scale ◽  
Sources Of Uncertainty ◽  
B Quark

Accurate determinations of the [Formula: see text]b-quark mass mb(mb) from σ(e+e-→ hadrons ) experimental data currently contain three comparable sources of uncertainty; the experimental uncertainty from moments of this cross-section, the uncertainty associated with αs(Mz), and the theoretical uncertainty associated with the renormalization scale. Through resummation of all logarithmic terms explicitly determined in the perturbative series by the renormalization-group (RG) equation, it is shown that the renormalization-scale dependence is virtually eliminated as a source of theoretical uncertainty in mb(mb). This resummation also reduces the estimated effect of higher-loop perturbative contributions, further reducing the theoretical uncertainties in mb(mb). Furthermore, such resummation techniques improve the agreement between the values of the [Formula: see text]b-quark mass extracted from the various moments of R(s) = σ(e+e-→ hadrons )/σpt [σpt = 4πα2/(3s)], obviating the need to choose an optimum moment for determining mb(mb). Based on this analysis, the resulting value of the b-mass is mb(mb) = 4.207 GeV ± 40 MeV , where the dominant uncertainty now arises from the experimental moments. Resummation techniques are also shown to reduce renormalization-scale dependence in the relation between b-quark [Formula: see text] and pole mass and in the relation between the pole and 1S mass.

scholarly journals Three-loop radiative-recoil corrections to hyperfine splitting in muonium

2005 ◽  
Vol 83 (4) ◽  
pp. 363-373 ◽  
Author(s):  
Michael I Eides ◽  
Howard Grotch ◽  
Valery A Shelyuto
Keyword(s):  
Experimental Data ◽  
Hyperfine Splitting ◽  
Theoretical Uncertainty ◽  
Invariant Sets ◽  
Mass Ratio ◽  
Gauge Invariant ◽  
Muon Mass ◽  
Long Time ◽  
Muonium Hyperfine ◽  
Leading Logarithm

We consider three-loop radiative-recoil corrections to hyperfine splitting in muonium. These corrections are enhanced by the large logarithm of the electron–muon mass ratio. The leading logarithm-cubed and logarithm-squared contributions were obtained a long time ago. We calculate the single-logarithmic and nonlogarithmic contributions of order α3(m/M)EF generated by gauge invariant sets of diagrams with one- and two-loop polarization insertions in diagrams with two exchanged photons and radiative photons, and by diagrams with one-loop radiative photon insertions both in the electron and muon lines. The results of this paper constitute a next step in the implementation of the program of reduction of the theoretical uncertainty of hyperfine splitting below 10 Hz. They improve the theory of hyperfine splitting, and affect the value of the electron–muon mass ratio extracted from experimental data on the muonium hyperfine splitting.PACS Nos.: 12.20.Ds, 31.30.Jv, 32.10.Fn, 36.10.Dr

scholarly journals Scale and isolation sensitivity of diphoton distributions at the LHC

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Thomas Gehrmann ◽  
Nigel Glover ◽  
Alexander Huss ◽  
James Whitehead
Keyword(s):  
Experimental Data ◽  
Functional Form ◽  
Theoretical Uncertainty ◽  
Precision Measurements ◽  
Leading Order ◽  
Scale Choice ◽  
Potential Sources ◽  
8 Tev

Abstract Precision measurements of diphoton distributions at the LHC display some tension with theory predictions, obtained at next-to-next-to-leading order (NNLO) in QCD. We revisit the theoretical uncertainties arising from the approximation of the experimental photon isolation by smooth-cone isolation, and from the choice of functional form for the renormalisation and factorisation scales. We find that the resulting variations are substantial overall, and enhanced in certain regions. We discuss the infrared sensitivity at the cone boundaries in cone-based isolation in related distributions. Finally, we compare predictions made with alternative choices of dynamical scale and isolation prescriptions to experimental data from ATLAS at 8 TeV, observing improved agreement. This contrasts with previous results, highlighting that scale choice and isolation prescription are potential sources of theoretical uncertainty that were previously underestimated.

Microdiffraction Patterns of Small Metallic Particles II; Theoretical Analysis

1982 ◽  
Vol 40 ◽  
pp. 668-669
Author(s):  
A. Gómez ◽  
P. Schabes-Retchkiman ◽  
M. José-Yacamán ◽  
T. Ocaña
Keyword(s):  
Experimental Data ◽  
Electron Diffraction ◽  
Theoretical Analysis ◽  
Size Range ◽  
Dynamical Theory ◽  
Metallic Particles ◽  
Splitting Effect

The splitting effect that is observed in microdiffraction pat-terns of small metallic particles in the size range 50-500 Å can be understood using the dynamical theory of electron diffraction for the case of a crystal containing a finite wedge. For the experimental data we refer to part I of this work in these proceedings.

Evidence for ordered Fe3Ni

1987 ◽  
Vol 45 ◽  
pp. 216-217
Author(s):  
K.B. Reuter ◽  
D.B. Williams ◽  
J.I. Goldstein
Keyword(s):  
Experimental Data ◽  
Martensitic Transformation ◽  
Electron Diffraction ◽  
Room Temperature ◽  
Direct Evidence ◽  
Transformation Product ◽  
Iron Meteorites ◽  
X Ray ◽  
Ni Content ◽  
Temperature Transformation

In the Fe-Ni system, although ordered FeNi and ordered Ni3Fe are experimentally well established, direct evidence for ordered Fe3Ni is unconvincing. Little experimental data for Fe3Ni exists because diffusion is sluggish at temperatures below 400°C and because alloys containing less than 29 wt% Ni undergo a martensitic transformation at room temperature. Fe-Ni phases in iron meteorites were examined in this study because iron meteorites have cooled at slow rates of about 10°C/106 years, allowing phase transformations below 400°C to occur. One low temperature transformation product, called clear taenite 2 (CT2), was of particular interest because it contains less than 30 wtZ Ni and is not martensitic. Because CT2 is only a few microns in size, the structure and Ni content were determined through electron diffraction and x-ray microanalysis. A Philips EM400T operated at 120 kV, equipped with a Tracor Northern 2000 multichannel analyzer, was used.

EELS white line intensities calculated for the 3d and 4d metals

1989 ◽  
Vol 47 ◽  
pp. 388-389
Author(s):  
C. C. Ahn ◽  
D. H. Pearson ◽  
P. Rez ◽  
B. Fultz
Keyword(s):  
Experimental Data ◽  
Line Intensity ◽  
Transition Probabilities ◽  
Initial Increase ◽  
White Line ◽  
Hartree Fock ◽  
Line Intensities ◽  
Integrated Intensity ◽  
X Ray Absorption ◽  
The Continuum

Previous experimental measurements of the total white line intensities from L2,3 energy loss spectra of 3d transition metals reported a linear dependence of the white line intensity on 3d occupancy. These results are inconsistent, however, with behavior inferred from relativistic one electron Dirac-Fock calculations, which show an initial increase followed by a decrease of total white line intensity across the 3d series. This inconsistency with experimental data is especially puzzling in light of work by Thole, et al., which successfully calculates x-ray absorption spectra of the lanthanide M4,5 white lines by employing a less rigorous Hartree-Fock calculation with relativistic corrections based on the work of Cowan. When restricted to transitions allowed by dipole selection rules, the calculated spectra of the lanthanide M4,5 white lines show a decreasing intensity as a function of Z that was consistent with the available experimental data.Here we report the results of Dirac-Fock calculations of the L2,3 white lines of the 3d and 4d elements, and compare the results to the experimental work of Pearson et al. In a previous study, similar calculations helped to account for the non-statistical behavior of L3/L2 ratios of the 3d metals. We assumed that all metals had a single 4s electron. Because these calculations provide absolute transition probabilities, to compare the calculated white line intensities to the experimental data, we normalized the calculated intensities to the intensity of the continuum above the L3 edges. The continuum intensity was obtained by Hartree-Slater calculations, and the normalization factor for the white line intensities was the integrated intensity in an energy window of fixed width and position above the L3 edge of each element.

A fuzzy neural network approach for modeling the growth kinetics of FeB and Fe2B layers during the boronizing process

2018 ◽  
Vol 106 (6) ◽  
pp. 603 ◽  
Author(s):  
Bendaoud Mebarek ◽  
Mourad Keddam
Keyword(s):  
Neural Network ◽  
Experimental Data ◽  
Fuzzy Neural Network ◽  
Treatment Time ◽  
Calculation Model ◽  
Average Error ◽  
Network Approach ◽  
Neural Network Approach ◽  
Fuzzy Neural ◽  
Kinetics Of

In this paper, we develop a boronizing process simulation model based on fuzzy neural network (FNN) approach for estimating the thickness of the FeB and Fe2B layers. The model represents a synthesis of two artificial intelligence techniques; the fuzzy logic and the neural network. Characteristics of the fuzzy neural network approach for the modelling of boronizing process are presented in this study. In order to validate the results of our calculation model, we have used the learning base of experimental data of the powder-pack boronizing of Fe-15Cr alloy in the temperature range from 800 to 1050 °C and for a treatment time ranging from 0.5 to 12 h. The obtained results show that it is possible to estimate the influence of different process parameters. Comparing the results obtained by the artificial neural network to experimental data, the average error generated from the fuzzy neural network was 3% for the FeB layer and 3.5% for the Fe2B layer. The results obtained from the fuzzy neural network approach are in agreement with the experimental data. Finally, the utilization of fuzzy neural network approach is well adapted for the boronizing kinetics of Fe-15Cr alloy.

Use of Posterior Probabilities to Evaluate Methods of Discriminant Analysis

1981 ◽  
Vol 20 (04) ◽  
pp. 207-212 ◽  
Author(s):  
J. Hermans ◽  
B. van Zomeren ◽  
J. W. Raatgever ◽  
P. J. Sterk ◽  
J. D. F. Habbema
Keyword(s):  
Experimental Data ◽  
Discriminant Analysis ◽  
Posterior Probabilities

By means of a case study the choice between several methods of discriminant analysis is presented. Experimental data of a two-groups problem with one or two variables is analysed. The different methods are compared according to posterior probabilities which can be computed for each subject and which are the basis of discriminant analysis. These posterior probabilities are analysed graphically as well as numerically.

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