scholarly journals B−→π−π0/ρ−ρ0to next-to-next-to-leading order in QCD factorization

2009 ◽  
Vol 80 (5) ◽  
Author(s):  
Guido Bell ◽  
Volker Pilipp
Keyword(s):  
Leading Order ◽  
Qcd Factorization

scholarly journals Next-to-leading-order study of J/ψ angular distributions in e+e− → J/ψ + ηc, χcJ at $$ \sqrt{s} $$ ≈ 10.6 GeV

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Zhan Sun
Keyword(s):  
Cross Sections ◽  
Charm Quark ◽  
Experimental Result ◽  
Angular Distributions ◽  
Matrix Elements ◽  
Leading Order ◽  
Charm Quark Mass ◽  
Qcd Factorization ◽  
Nonrelativistic Qcd ◽  
Good Agreement

Abstract In this paper, we present a detailed next-to-leading-order (NLO) study of J/ψ angular distributions in e+e−→ J/ψ + ηc, χcJ (J = 0, 1, 2) within the nonrelativistic QCD factorization (NRQCD). The numerical NLO expressions for total and differential cross sections, i.e., $$ \frac{d\sigma}{d\cos \theta } $$ dσ d cos θ = A + B cos2θ, are both derived. With the inclusion of the newly-calculated QCD corrections to A and B, the αθ (= B/A) parameters in J/ψ + χc0 and J/ψ + χc1 are moderately enhanced, while the magnitude of αθJ/ψ+χc2 is significantly reduced; regarding the production of J/ψ + ηc, the αθ value remains unchanged. By comparing with experiment, we find the predicted αθJ/ψ+ηc is in good agreement with the Belle measurement; however, αθJ/ψ+χc0 is still totally incompatible with the experimental result, and this discrepancy seems to hardly be cured by proper choices of the charm-quark mass, the renormalization scale, and the NRQCD matrix elements.

Study of Υ(nS) → Bcρ and BcK∗ decays within the QCD factorization

2016 ◽  
Vol 31 (38) ◽  
pp. 1650209
Author(s):  
Qin Chang ◽  
Yunyun Zhang ◽  
Lin Han
Keyword(s):  
Large Hadron Collider ◽  
Quantum Chromodynamics ◽  
Branching Fractions ◽  
Hadron Collider ◽  
Heavy Flavor ◽  
Leading Order ◽  
Text Data ◽  
Weak Decays ◽  
Qcd Factorization ◽  
Belle Ii

Motivated by the heavy-flavor experiments at running Large Hadron Collider (LHC) and upgrading SuperKEKB, which provide abundant [Formula: see text] data samples, the tree-dominated [Formula: see text] and [Formula: see text] (n =1, 2, 3) weak decays are studied within the framework of quantum chromodynamics (QCD) factorization. The QCD corrections to the longitudinal and transverse amplitudes are evaluated at next-to-leading order, and the branching fractions and polarization fractions are predicted. Numerically, the [Formula: see text] decays have relatively large branching fractions at the order of [Formula: see text] and are in the scope of the LHC and SuperKEKB/Belle-II experiments.

scholarly journals NEXT-TO-LEADING ORDER TESTS OF NON-RELATIVISTIC-QCD FACTORIZATION WITH J/ψ YIELD AND POLARIZATION

2013 ◽  
Vol 28 (09) ◽  
pp. 1350027 ◽  
Author(s):  
MATHIAS BUTENSCHOEN ◽  
BERND A. KNIEHL
Keyword(s):  
Relativistic Quantum ◽  
Distance Matrix ◽  
Data Sets ◽  
Leading Order ◽  
Fixed Target ◽  
Polarization Data ◽  
Long Distance ◽  
Qcd Factorization ◽  
Global Fit ◽  
Photo Production

We report on recent progress in testing the factorization formalism of non-relativistic quantum chromodynamics (NRQCD) at next-to-leading order (NLO) for J/ψ yield and polarization. We demonstrate that it is possible to unambiguously determine the leading color-octet (CO) long-distance matrix elements (LDMEs) in compliance with the velocity scaling rules through a global fit to experimental data of unpolarized J/ψ production in pp, [Formula: see text], ep, γγ, and e+e-collisions. Three data sets not included in the fit, from hadro-production and from photo-production in the fixed-target and colliding-beam modes, are nicely reproduced. The polarization observables measured in different frames at DESY HERA and CERN LHC reasonably agree with NLO NRQCD predictions obtained using the LDMEs extracted from the global fit, while measurements at the FNAL Tevatron exhibit severe disagreement. We demonstrate that the alternative LDME sets recently obtained, with different philosophies, in two other NLO NRQCD analyses of J/ψ yield and polarization also fail to reconcile the Tevatron polarization data with the other available world data.

ANALYSIS OF D→ππ BEYOND NAIVE FACTORIZATION

2004 ◽  
Vol 19 (21) ◽  
pp. 1623-1631 ◽  
Author(s):  
XIANG-YAO WU ◽  
XIN-GUO YIN ◽  
DE-BAO CHEN ◽  
YI-QING GUO ◽  
YU ZENG
Keyword(s):  
Calculation Result ◽  
Final State Interaction ◽  
Decay Channel ◽  
Soft Gluon ◽  
Experimental Result ◽  
Leading Order ◽  
Final State ◽  
Sum Rule ◽  
Decay Channels ◽  
Qcd Factorization

We analyze the D→ππ decay channels at the leading order, αs corrections with the QCD factorization and the soft-gluon corrections with the light cone QCD sum rule. Comparing with the experimental result, the calculations of the D0→π+π- and D+→π+π0 decay are much better under the consideration of the contributions of factorization parts, αs corrections and soft-gluon effects. However, the calculation result is one order less than the experimental result in D0→π0π0 decay. It may have large effects of final state interaction in the decay channel.

scholarly journals QCD Evolution of Nuclear Quark-Gluon Correlation Function

2015 ◽  
Vol 37 ◽  
pp. 1560061
Author(s):  
Hongxi Xing ◽  
Zhong-Bo Kang ◽  
Enke Wang ◽  
Xin-Nian Wang
Keyword(s):  
Correlation Function ◽  
Transverse Momentum ◽  
Evolution Equation ◽  
Energy Dependence ◽  
Cross Sections ◽  
Differential Cross ◽  
Transport Parameter ◽  
Leading Order ◽  
Dilepton Production ◽  
Qcd Factorization

We summarize the results on the next-to-leading order (NLO) calculations of transverse momentum broadening in semi-inclusive deeply inelastic e + A scattering (SIDIS) and Drell-Yan dilepton production (DY) in p + A collisions. The corresponding transverse momentum weighted differential cross sections are shown to factorize at NLO. Our calculations identify the QCD evolution equation for the quark-gluon correlation function, and also confirm the universality of the associated quark-gluon correlation function in SIDIS and DY. The evolution equation can be further applied to determine the QCD factorization scale and the energy dependence of the jet transport parameter [Formula: see text].

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