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.

scholarly journals Dipole subtraction at next-to-leading order in nonrelativistic-QCD factorization

2020 ◽  
Vol 950 ◽  
pp. 114843 ◽  
Author(s):  
Mathias Butenschoen ◽  
Bernd A. Kniehl
Keyword(s):  
Leading Order ◽  
Qcd Factorization ◽  
Nonrelativistic Qcd

Angular distributions of the 12C(e,p)e′ reaction at Ee = 200 MeV

1981 ◽  
Vol 59 (2) ◽  
pp. 271-274 ◽  
Author(s):  
G. J. Lolos ◽  
S. Hontzeas ◽  
R. M. Sealock
Keyword(s):  
Electron Energy ◽  
Cross Sections ◽  
Differential Cross ◽  
Proton Energy ◽  
Incident Electron ◽  
Incident Electron Energy ◽  
Angular Distributions ◽  
Differential Cross Sections ◽  
Good Agreement

Double differential cross sections at six angles ranging from 45° to 143° have been measured for the 12C(e,p)e′ reaction. The proton energy ranged from 15.6 to 17.2 MeV at an incident electron energy of 200 MeV. At the backward angles our results are in good agreement with data reported by Vysotskaya and Afanas'ev but for forward angles the results are lower.

States in 152Sm populated by the (t,α) reaction

1977 ◽  
Vol 55 (13) ◽  
pp. 1137-1144 ◽  
Author(s):  
C. R. Hirning ◽  
D. G. Burke
Keyword(s):  
Cross Sections ◽  
Attenuation Factor ◽  
Matrix Elements ◽  
Coriolis Coupling ◽  
Reaction Products ◽  
Plane Detector ◽  
Scientific Laboratory ◽  
Coupling Calculation ◽  
Good Agreement ◽  
Focal Plane Detector

Levels in the deformed even–even nucleus 152Sm have been populated by the (t,α) reaction using beams of 15 MeV tritons from the model FN tandem Van de Graaff accelerator at the Los Alamos Scientific Laboratory. For the initial experiments in the series the reaction products were analyzed in an Elbek magnetic spectrograph and detected with nuclear emulsions. Those done later made use of the Q3D magnetic spectrometer and helical-cathode focal plane detector. On the basis of levels observed in adjacent odd-Z nuclei and some previous (α,2nγ) results, a rotational band built on the Kπ = 5−, 5/2+[413] + 5/2−[532] two-quasiparticle state has been identified. A Coriolis coupling calculation has been done, which gives good agreement with experimental energies and cross sections when an attenuation factor of 0.31 is used for the Coriolis matrix elements.

scholarly journals Microscopic analysis of elastic scattering cross sections for different densities of $^{8}$Li nucleus on light, medium and heavy mass targets

2019 ◽  
Vol 65 (4 Jul-Aug) ◽  
pp. 404
Author(s):  
M. Aygun ◽  
And Z. Aygun
Keyword(s):  
Elastic Scattering ◽  
Cross Sections ◽  
Microscopic Analysis ◽  
Angular Distributions ◽  
Weakly Bound ◽  
Density Distributions ◽  
Double Folding ◽  
Scattering Cross Sections ◽  
Light Medium ◽  
Good Agreement

The elastic scattering angular distributions of weakly bound nucleus$^{8}$Li on $^{7}$Li, $^{9}$Be, $^{12}$C, $^{13}$C, $^{14}$N,$^{27}$Al, $^{51}$V, $^{58}$Ni, and $^{208}$Pb are analyzed atvarious incident energies. For this purpose, the real potential isgenerated for nine different density distributions of the $^{8}$Linucleus by using the double folding model within the optical model.The theoretical results are in good agreement with the experimentaldata. In our study, also, new and practical sets of imaginarypotentials for the investigated densities are derived.

scholarly journals Inclusive production of heavy quarkonia in pNRQCD

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Nora Brambilla ◽  
Hee Sok Chung ◽  
Antonio Vairo
Keyword(s):  
Cross Sections ◽  
Production Cross ◽  
Distance Matrix ◽  
Effective Field ◽  
Heavy Quarkonia ◽  
Inclusive Production ◽  
Theory Approach ◽  
Matrix Elements ◽  
Long Distance ◽  
Nonrelativistic Qcd

Abstract We develop a formalism for computing inclusive production cross sections of heavy quarkonia based on the nonrelativistic QCD and the potential nonrelativistic QCD effective field theories. Our formalism applies to strongly coupled quarkonia, which include excited charmonium and bottomonium states. Analogously to heavy quarkonium decay processes, we express nonrelativistic QCD long-distance matrix elements in terms of quarkonium wavefunctions at the origin and universal gluonic correlators. Our expressions for the long-distance matrix elements are valid up to corrections of order $$ 1/{N}_c^2 $$ 1 / N c 2 . These expressions enhance the predictive power of the nonrelativistic effective field theory approach to inclusive production processes by reducing the number of nonperturbative unknowns, and make possible first-principle determinations of long-distance matrix elements once the gluonic correlators are known. Based on this formalism, we compute the production cross sections of P-wave charmonia and bottomonia at the LHC, and find good agreement with measurements.

scholarly journals The strangest proton?

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Ferran Faura ◽  
Shayan Iranipour ◽  
Emanuele R. Nocera ◽  
Juan Rojo ◽  
Maria Ubiali
Keyword(s):  
Cross Sections ◽  
Global Analysis ◽  
Charm Quark ◽  
Distribution Functions ◽  
Boson Production ◽  
Parton Distribution Functions ◽  
Charm Quarks ◽  
Charm Quark Mass ◽  
Input Dataset ◽  
Qcd Analysis

AbstractWe present an improved determination of the strange quark and antiquark parton distribution functions of the proton by means of a global QCD analysis that takes into account a comprehensive set of strangeness-sensitive measurements: charm-tagged cross sections for fixed-target neutrino–nucleus deep-inelastic scattering, and cross sections for inclusive gauge-boson production and W-boson production in association with light jets or charm quarks at hadron colliders. Our analysis is accurate to next-to-next-to-leading order in perturbative QCD where available, and specifically includes charm-quark mass corrections to neutrino–nucleus structure functions. We find that a good overall description of the input dataset can be achieved and that a strangeness moderately suppressed in comparison to the rest of the light sea quarks is strongly favored by the global analysis.

scholarly journals Decoupling of charm beyond leading order

2018 ◽  
Vol 175 ◽  
pp. 10001 ◽  
Author(s):  
Francesco Knechtli ◽  
Tomasz Korzec ◽  
Björn Leder ◽  
Graham Moir
Keyword(s):  
Quark Mass ◽  
Charm Quark ◽  
Direct Access ◽  
Effective Theory ◽  
Leading Order ◽  
Charm Quarks ◽  
Charm Quark Mass ◽  
Power Corrections ◽  
Low Energies ◽  
Pure Gauge Theory

We study the effective theory of decoupling of a charm quark at low energies. We do this by simulating a model, QCD with two mass-degenerate charm quarks. At leading order the effective theory is a pure gauge theory. By computing ratios of hadronic scales we have direct access to the power corrections in the effective theory. We show that these corrections follow the expected leading behavior, which is quadratic in the inverse charm quark mass.

The Repulsive Part of the Potential Between Hg Atoms and Light Atomic Projectiles

1972 ◽  
Vol 50 (17) ◽  
pp. 1938-1948 ◽  
Author(s):  
A. van Wijngaarden ◽  
B. Miremadi ◽  
W. E. Baylis
Keyword(s):  
Cross Sections ◽  
Target Chamber ◽  
Angular Distributions ◽  
Interatomic Potentials ◽  
Scattering Parameters ◽  
Thomas Fermi ◽  
Monoenergetic Beam ◽  
Charge States ◽  
Repulsive Part ◽  
Good Agreement

Interatomic potentials are studied by means of a crossed beam apparatus consisting of a target chamber in which a monoenergetic beam of H, He, B, and N ions of energies E < 70 keV interacts with a thermal beam of Hg atoms. Angular distributions for the scattering of all charge states of 1H, 4He, 11B, and 14N are measured in the range of 17° < θL < 60°. All measured cross sections are in good agreement with the theory for scattering in a Thomas–Fermi potential to which Lindhard's theoretical estimates are shown to be quite accurate approximations. A Padé approximant is derived for the Thomas–Fermi potential and is used to calculate tables of Thomas–Fermi scattering parameters.

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.

Sign in / Sign up

Export Citation Format

Share Document