scholarly journals INCLUSIVE PRODUCTION OF FOUR CHARM HADRONS AT B-FACTORIES

2006 ◽  
Vol 21 (04) ◽  
pp. 922-925
Author(s):  
Daekyoung Kang ◽  
Jungil Lee
Keyword(s):  
Scattering Amplitude ◽  
Belle Collaboration ◽  
Inclusive Production ◽  
Hard Scattering ◽  
Factorization Approach ◽  
Qcd Factorization ◽  
Nonrelativistic Qcd ◽  
Theoretical Predictions ◽  
Perturbative Corrections

Measurements by the Belle Collaboration of the exclusive J/ψ + ηc and inclusive [Formula: see text] productions in e+e- annihilation differ substantially from theoretical predictions based on the nonrelativistic QCD factorization approach. In order to test if such a discrepancy is originated from the large perturbative corrections to the hard-scattering amplitude, we study inclusive production of four charm hadrons in e+e- annihilation at B factories.

scholarly journals CHARMONIUM POLARIZATION AT THE TEVATRON

2001 ◽  
Vol 16 (supp01b) ◽  
pp. 483-485
Author(s):  
JUNGIL LEE
Keyword(s):  
Factorization Approach ◽  
Qcd Factorization ◽  
Nonrelativistic Qcd

The current issues on the polarization of prompt J/ψ at the Tevatron is discussed. The prediction based on the nonrelativistic QCD factorization approach agrees with measurements from the CDF collaboration at intermediate values of pT, but disagrees at the large values of pT measured.

scholarly journals Branching Ratio and CP Violation in B s 0 ¯ → ϕϕ Decay in the Framework of QCD Factorization

Atoms ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 22 ◽  
Author(s):  
E. H. Raslan ◽  
H. R. Khan
Keyword(s):  
Cp Violation ◽  
Helicity Amplitude ◽  
Branching Ratio ◽  
Analytic Calculation ◽  
Meson Decay ◽  
Experimental Measurements ◽  
Factorization Approach ◽  
Qcd Factorization ◽  
Theoretical Predictions ◽  
Charge Parity

We present an analytic calculation of Branching Ratio (BR) and Charge-Parity (CP) violating asymmetries of the B s 0 ¯ meson decay into the two light vectors ϕ ϕ . In doing this we calculate the helicity amplitude of the present decay in the framework of QCD factorization approach. We find the BR of B s 0 ¯ → ϕ ϕ = ( 1.56 ± 0.23 ) × 10 − 5 . We also calculate the direct CP violation, CP violation in mixing and CP violation due to interference which are A C P dir = 0.00355 ± 0.00152 , A C P mix = − 0.00629 ± 0.03119 and A C P Δ Γ = 0.99997 ± 0.00019 , respectively. Our results are in agreement with the recent theoretical predictions and experimental measurements.

Branching ratio and CP violation in Bs0 → K∗0K̄∗0 decay in the framework of QCD factorization

2020 ◽  
Vol 35 (24) ◽  
pp. 2050201 ◽  
Author(s):  
E. H. Raslan ◽  
H. R. Khan
Keyword(s):  
Cp Violation ◽  
Quantum Chromodynamics ◽  
Branching Ratio ◽  
Meson Decay ◽  
Experimental Measurements ◽  
Full Agreement ◽  
Factorization Approach ◽  
Qcd Factorization ◽  
Theoretical Predictions ◽  
Charge Parity

We present an analytic calculation of Branching Ratio (BR) and Charge-Parity (CP) violating asymmetries of the [Formula: see text] meson decay into the two light vectors [Formula: see text] by calculating the helicity amplitude in the framework of quantum chromodynamics (QCD) factorization approach. We find the BR of [Formula: see text] which is in full agreement with the recent theoretical predictions and experimental measurements. We also calculate the direct CP violation, CP violation in mixing and CP violation due to interference which are [Formula: see text], [Formula: see text], and [Formula: see text], respectively.

scholarly journals Universal opening of four-loop scattering amplitudes to trees

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Selomit Ramírez-Uribe ◽  
Roger J. Hernández-Pinto ◽  
Germán Rodrigo ◽  
German F. R. Sborlini ◽  
William J. Torres Bobadilla
Keyword(s):  
Scattering Amplitudes ◽  
General Expression ◽  
High Energy Physics ◽  
Scattering Amplitude ◽  
Causal Structure ◽  
High Energy ◽  
Quantum Field Theories ◽  
Efficient Computation ◽  
Perturbative Approach ◽  
Theoretical Predictions

Abstract The perturbative approach to quantum field theories has made it possible to obtain incredibly accurate theoretical predictions in high-energy physics. Although various techniques have been developed to boost the efficiency of these calculations, some ingredients remain specially challenging. This is the case of multiloop scattering amplitudes that constitute a hard bottleneck to solve. In this paper, we delve into the application of a disruptive technique based on the loop-tree duality theorem, which is aimed at an efficient computation of such objects by opening the loops to nondisjoint trees. We study the multiloop topologies that first appear at four loops and assemble them in a clever and general expression, the N4MLT universal topology. This general expression enables to open any scattering amplitude of up to four loops, and also describes a subset of higher order configurations to all orders. These results confirm the conjecture of a factorized opening in terms of simpler known subtopologies, which also determines how the causal structure of the entire loop amplitude is characterized by the causal structure of its subtopologies. In addition, we confirm that the loop-tree duality representation of the N4MLT universal topology is manifestly free of noncausal thresholds, thus pointing towards a remarkably more stable numerical implementation of multiloop scattering amplitudes.

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