Width Difference
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2022 ◽  
Vol 258 ◽  
pp. 04002
Vladyslav Shtabovenko

The width difference ΔΓs that can be extracted from lifetime measurements of the two mass eigenstates of the Bs0−B¯s0 system is one of the key flavor precision observables and has been experimentally measured at per cent level accuracy. The current theory prediction is much less accurate and a sizable reduction of scale uncertainties can only be achieved by means of evaluating the uncalculated 2- and 3-loop QCD corrections. This is precisely the issue addressed in this work where we report on the results that have been obtained so far and explain some of the technical and conceptual challenges that we encountered in the course of our calculations.

Zhonghang Wu ◽  
Pengfei Hou ◽  
Wei Li ◽  
Tianbao Zhu ◽  
Peipei Wang ◽  

BACKGROUND: Manual or machine-based analysis of chest radiographs needs the images acquired with technical adequacy. Currently, the equidistance between the medial end of clavicles and the center of spinous processes serves as the only criterion to assess whether a frontal PA chest radiograph is taken with any rotation. However, this measurement is normally difficult to implement because there exists overlapping of anatomies within the region. Moreover, there is no way available to predict exact rotating angles even the distances were correctly measured from PA chest radiographs. OBJECTIVE: To quantitatively assess positioning adequacy of PA chest examination, this study proposes and investigates a new method to estimate rotation angles from asymmetric projection of thoracic cage on radiographs. METHOD: By looking into the process of radiographic projection, generalized expressions have been established to correlate rotating angles of thorax with projection difference of left and right sides of thoracic cage. A trunk phantom with different positioning angles is employed to acquire radiographs as standard reference to verify the theoretical expressions. RESULTS: The angles estimated from asymmetric projections of thoracic cage yield good agreement with those actual rotated angles, and an approximate linear relationship exists between rotation angle and asymmetric projection of thoracic cage. Under the experimental projection settings, every degree of rotation corresponds to the width difference of two sides of thoracic cage around 13–14 pixels. CONCLUSION: The proposed new method may be used to quantify rotating angles of chest and assess image quality for thoracic radiographic examination.

2021 ◽  
Vol 2021 (9) ◽  
Hiroyuki Umeeda

Abstract We study local quark-hadron duality and its violation for the $$ {D}^0-{\overline{D}}^0 $$ D 0 − D ¯ 0 , $$ {B}_d^0-{\overline{B}}_d^0 $$ B d 0 − B ¯ d 0 and $$ {B}_s^0-{\overline{B}}_s^0 $$ B s 0 − B ¯ s 0 mixings in the ’t Hooft model, offering a laboratory to test QCD in two-dimensional spacetime together with the large-Nc limit. With the ’t Hooft equation being numerically solved, the width difference is calculated as an exclusive sum over two-body decays. The obtained rate is compared to inclusive one that arises from four-quark operators to check the validity of the heavy quark expansion (HQE). In view of the observation in four-dimensions that the HQE prediction for the width difference in the $$ {D}^0-{\overline{D}}^0 $$ D 0 − D ¯ 0 mixing is four orders of magnitude smaller than the experimental data, in this work we investigate duality violation in the presence of the GIM mechanism. We show that the order of magnitude of the observable in the $$ {D}^0-{\overline{D}}^0 $$ D 0 − D ¯ 0 mixing is enhanced in the exclusive analysis relative to the inclusive counterpart, when the 4D-like phase space function is used for the inclusive analysis. By contrast, it is shown that for the $$ {B}_d^0-{\overline{B}}_d^0 $$ B d 0 − B ¯ d 0 and $$ {B}_s^0-{\overline{B}}_s^0 $$ B s 0 − B ¯ s 0 mixings, small yet non-negligible corrections to the inclusive result emerge, which are still consistent with what is currently indicated in four-dimensions.

2021 ◽  
Vol 2021 (7) ◽  
Marvin Gerlach ◽  
Ulrich Nierste ◽  
Vladyslav Shtabovenko ◽  
Matthias Steinhauser

Abstract We consider two-loop QCD corrections to the element $$ {\Gamma}_{12}^q $$ Γ 12 q of the decay matrix in Bq−$$ {\overline{B}}_q $$ B ¯ q mixing, q = d, s, in the leading power of the Heavy Quark Expansion. The calculated contributions involve one current-current and one penguin operator and constitute the next step towards a theory prediction for the width difference ∆Γs matching the precise experimental data. We present compact analytic results for all matching coefficients in an expansion in mc/mb up to second order. Our new corrections are comparable in size to the current experimental error and slightly increase ∆Γs.

2021 ◽  
Vol 81 (4) ◽  
G. Aad ◽  
B. Abbott ◽  
D. C. Abbott ◽  
O. Abdinov ◽  

AbstractA measurement of the $$ B_{s}^{0} \rightarrow J/\psi \phi $$ B s 0 → J / ψ ϕ decay parameters using $$ 80.5\, \mathrm {fb^{-1}} $$ 80.5 fb - 1 of integrated luminosity collected with the ATLAS detector from 13 $$\text {Te}\text {V}$$ Te proton–proton collisions at the LHC is presented. The measured parameters include the CP-violating phase $$\phi _{s} $$ ϕ s , the width difference $$ \Delta \Gamma _{s}$$ Δ Γ s between the $$B_{s}^{0}$$ B s 0 meson mass eigenstates and the average decay width $$ \Gamma _{s}$$ Γ s . The values measured for the physical parameters are combined with those from $$ 19.2\, \mathrm {fb^{-1}} $$ 19.2 fb - 1 of 7 and 8 $$\text {Te}\text {V}$$ Te data, leading to the following: $$\begin{aligned} \phi _{s}= & {} -0.087 \pm 0.036 ~\mathrm {(stat.)} \pm 0.021 ~\mathrm {(syst.)~rad} \\ \Delta \Gamma _{s}= & {} 0.0657 \pm 0.0043 ~\mathrm {(stat.)}\pm 0.0037 ~\mathrm {(syst.)~ps}^{-1} \\ \Gamma _{s}= & {} 0.6703 \pm 0.0014 ~\mathrm {(stat.)}\pm 0.0018 ~\mathrm {(syst.)~ps}^{-1} \end{aligned}$$ ϕ s = - 0.087 ± 0.036 ( stat . ) ± 0.021 ( syst . ) rad Δ Γ s = 0.0657 ± 0.0043 ( stat . ) ± 0.0037 ( syst . ) ps - 1 Γ s = 0.6703 ± 0.0014 ( stat . ) ± 0.0018 ( syst . ) ps - 1 Results for $$\phi _{s} $$ ϕ s and $$ \Delta \Gamma _{s}$$ Δ Γ s are also presented as 68% confidence level contours in the $$\phi _{s} $$ ϕ s –$$ \Delta \Gamma _{s}$$ Δ Γ s plane. Furthermore the transversity amplitudes and corresponding strong phases are measured. $$\phi _{s} $$ ϕ s and $$ \Delta \Gamma _{s}$$ Δ Γ s measurements are in agreement with the Standard Model predictions.

2020 ◽  
Vol 35 (34n35) ◽  
pp. 2044006
Vladimir Nikolaenko

A measurement of [Formula: see text] decay parameters using data collected by the ATLAS detector in [Formula: see text] collisions at 13 TeV in 2015–2017 is performed. Integrated luminosity of this sample is 80.5 fb[Formula: see text]. The measurement of physical parameters are statistically combined with results obtained from Run 1 data at 7 and 8 TeV. The measured value of CP-violating phase [Formula: see text] is obtained, which has significantly better precision in comparison with Run 1 result. Precision of other physical parameters is also improved, including the decay width difference [Formula: see text]. Further improvement is expected from the use of full Run 2 statistics, as well as from modifications in the analysis.

2020 ◽  
Vol 102 (3) ◽  
Hrachia M. Asatrian ◽  
Hrachya H. Asatryan ◽  
Artyom Hovhannisyan ◽  
Ulrich Nierste ◽  
Sergey Tumasyan ◽  

2020 ◽  
Vol 57 (6) ◽  
pp. 700-706
Neha Bhutiani ◽  
Tulika Tripathi ◽  
Mahesh Verma ◽  
Padam Singh Bhandari ◽  
Priyank Rai

Objective: To analyze the effects of presurgical nasoalveolar molding (PNAM) in newborns with cleft lip and palate and evaluate its postsurgical stability at 1-year follow-up using a nasal stent. Design: Prospective clinical trial. Setting: Department of Orthodontics, Maulana Azad Institute of Dental Sciences, Delhi. Patients: Patients with cleft lip and palate of 0 to 6 months. Sample size 25 recruited, 16 satisfactorily completed the procedure. Interventions: Presurgical nasoalveolar molding done as indicated in all the patients. Postsurgical external nasal stents were given for 1 year to maintain the nasal correction. Main Outcome Measures: Changes in cleft defect and maxillary arch were recorded pre- and post-PNAM. Changes in nasal morphological parameters assessed pre- and post-PNAM and 1 year after surgical repair following the use of nasal stent. Results: There was a significant reduction in cleft defect assessed both intraorally ( 4.16 mm) and extra orally ( 4.42 mm) at the end of PNAM therapy (average treatment time 4 months). The nasal morphology improved with an increase in columella height (1.5 mm) and reduction in columella width. Bialar width reduced (2.90 mm) with an increase in nostril height ( 2.10 mm). Better symmetry was achieved in all cases as the nostril height and width difference changed significantly pre- and post-nasoalveolar molding. The percentage increase in columella height was greater for infants less than 6 weeks. Conclusions: Presurgical nasoalveolar molding considerably reduces the cleft gap and improves arch form making surgical union easier along with improved nasal morphology which can be maintained at 1-year postsurgery by use of a postsurgical external nasal stent.

2020 ◽  
Vol 124 (8) ◽  
Christine T. H. Davies ◽  
Judd Harrison ◽  
G. Peter Lepage ◽  
Christopher J. Monahan ◽  
Junko Shigemitsu ◽  

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