scholarly journals Direct production of χc1 at BESIII

2019 ◽  
Vol 202 ◽  
pp. 06009
Author(s):  
Yuping Guo
Keyword(s):  
Data Analysis ◽  
Production Rate ◽  
Neutral Current ◽  
High Luminosity ◽  
Direct Production ◽  
Two Photon ◽  
Quantum Numbers ◽  
Decay Products ◽  
Electron Positron Annihilation ◽  
Electron Positron

The production of resonances in electron-positron annihilation has only been observed for states with quantum numbers JPC = 1−−, while C = +1 resonances appear only among the decay products. The direct production of the 1++ states could happen through two-photon or neutral current. Due to the smallness of the production rate, this process has never been verified experimentally. With the high luminosity and good performance of the BESIII experiment, a search of the direct production of the 1++ state in charmonium region, χc1, is undergoing with dedicated data samples around the χc1 mass. An overview of the data analysis will be presented.

scholarly journals IMPLICATIONS OF AN R-SCAN FOR CHARM PHYSICS

2014 ◽  
Vol 35 ◽  
pp. 1460386
Author(s):  
JOHANN H. KÜHN
Keyword(s):  
Cross Section ◽  
Quark Mass ◽  
Charm Physics ◽  
Threshold Region ◽  
High Luminosity ◽  
Electron Positron Annihilation ◽  
Electron Positron ◽  
The Impact ◽  
The Continuum

The impact of improved measurements of the cross section for electron-positron annihilation into hadrons in the charm threshold region is discussed. Two aspects are studied in detail: i.) A significant reduction of the experimental error of the electronic width of the narrow resonances J/ψ and ψ′ and of the continuum cross section from the open charm threshold up to 4.6 GeV will lead to a correspondingly improved determination of the charmed quark mass; ii) A high luminosity measurement with 24 pb-1 at three points and with a spacing of 2 MeV around [Formula: see text] may allow to observe the direct, resonant production of χc1.

Two-photon electron-positron annihilation in an external magnetic field

1968 ◽  
Vol 11 (3) ◽  
pp. 16-19
Author(s):  
I. M. Ternov ◽  
B. A. Lysov ◽  
O. F. Dorofeev ◽  
O. S. Pavlova
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Positron Annihilation ◽  
Two Photon ◽  
Electron Positron Annihilation ◽  
Electron Positron

scholarly journals Direct, Resonant Production of States with Positive Charge Conjugation in Electron-Positron Annihilation

2019 ◽  
Vol 218 ◽  
pp. 02010
Author(s):  
Henryk Czyż ◽  
Johann H. Kühn ◽  
Szymon Tracz
Keyword(s):  
Positron Annihilation ◽  
Relative Phase ◽  
Positive Charge ◽  
Practical Purpose ◽  
The State ◽  
Recent Theory ◽  
Production Amplitude ◽  
Direct Production ◽  
Electron Positron Annihilation ◽  
Electron Positron

Recent theory results on direct production of resonances with positive charge conjugationin electron-positron annihilation are reviewed. The strong modeldependence is emphasized, with predictions varying between 0.03 eV and 0.43 eV for the charmonium state with JPC = 1++ and between0.16 eV and4.25 eV for the state with JPC =2++. For the state with JPC = 0++ the cross section is of O $ \left( {\mathop m\nolimits_e^2 /\mathop M\nolimits_x^2 } \right) $ and thus negligeable for all practical purpose. The importance of the relative phase of the production amplitude is emphasized.

THE NLO QCD CALCULATION OF SEA QUARK DISTRIBUTIONS IN THE CORGI APPROACH, BASED ON THE CONSTITUENT QUARK MODEL

2007 ◽  
Vol 22 (24) ◽  
pp. 4519-4535 ◽  
Author(s):  
A. MIRJALILI ◽  
K. KESHAVARZIAN
Keyword(s):  
Quark Model ◽  
Mellin Transform ◽  
Constituent Quark ◽  
Constituent Quark Model ◽  
Standard Approach ◽  
Unknown Parameters ◽  
Electron Positron Annihilation ◽  
Electron Positron ◽  
Physical Scale ◽  
Good Agreement

Sea quark distributions in the NLO approximation, based on the phenomenological valon model or constituent quark model are analyzed. We use the parametrized inverse Mellin transform technique to perform a direct fit with available experimental data and obtain the unknown parameters of the distributions. We try to extend the calculation to the NLO approximation for the singlet and nonsinglet cases in DIS phenomena. We do also the same calculation for electron–positron annihilation. The resulting sea distributions are effectively independent of the process used. The approach of complete RG improvement (CORGI) is employed and the results are compared with the standard approach of perturbative QCD in the [Formula: see text] scheme with a physical scale. The comparisons with data are in good agreement. As is expected, the results in the CORGI approach indicate a better agreement to the data than the NLO calculation in the standard approach.

scholarly journals Power corrections to event shapes using Eikonal dressed gluon exponentiation

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Neelima Agarwal ◽  
Ayan Mukhopadhyay ◽  
Sourav Pal ◽  
Anurag Tripathi
Keyword(s):  
Cross Section ◽  
Established Method ◽  
Hadronic Event ◽  
Power Corrections ◽  
Electron Positron Annihilation ◽  
Electron Positron ◽  
Lhc Physics ◽  
Event Shapes ◽  
Jet Shapes

AbstractEvent shapes are classical tools for the determination of the strong coupling and for the study of hadronization effects in electron-positron annihilation. In the context of analytical studies, hadronization corrections take the form of power-suppressed contributions to the cross section, which can be extracted from the perturbative ambiguity of Borel-resummed distributions. We propose a simplified version of the well-established method of Dressed Gluon Exponentiation (DGE), which we call Eikonal DGE (EDGE), which determines all dominant power corrections to event shapes by means of strikingly elementary calculations. We believe our method can be generalized to hadronic event shapes and jet shapes of relevance for LHC physics.

scholarly journals Calculation of the Doppler broadening of the electron-positron annihilation radiation in defect-free bulk materials

2000 ◽  
Vol 61 (15) ◽  
pp. 10092-10099 ◽  
Author(s):  
V. J. Ghosh ◽  
M. Alatalo ◽  
P. Asoka-Kumar ◽  
B. Nielsen ◽  
K. G. Lynn ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Annihilation Radiation ◽  
Doppler Broadening ◽  
Bulk Materials ◽  
Electron Positron Annihilation ◽  
Electron Positron
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