Threshold pion photoproduction in the Skyrme model

1992 ◽  
Vol 70 (9) ◽  
pp. 711-718 ◽  
Author(s):  
Jingbo Zhang ◽  
Nader Mobed
Keyword(s):  
Experimental Data ◽  
Degrees Of Freedom ◽  
Pion Production ◽  
Neutral Pion ◽  
Unique Feature ◽  
Skyrme Model ◽  
Pion Photoproduction ◽  
Pole Term ◽  
Nucleon Pole ◽  
Important Test

Threshold photoproduction of pions on the nucleon is studied in the Skyrme model. Both the rotational and translational degrees of freedom of the Skyrmion are included in the calculations. It is found that in the case of neutral pion production there is a sizeable cancellation between the nucleon pole term and the anomalous contact term. This cancellation is a unique feature of the model and provides an important test of the validity of the model. A definitive conclusion must await a resolution of the existing controversies about the experimental data.

Three-dimensional asymmetric maximum weight lifting prediction considering dynamic joint strength

2021 ◽  
pp. 095441192098703
Author(s):  
Rahid Zaman ◽  
Yujiang Xiang ◽  
Jazmin Cruz ◽  
James Yang
Keyword(s):  
Experimental Data ◽  
Degrees Of Freedom ◽  
Inverse Dynamics ◽  
Three Dimensional ◽  
Optimization Method ◽  
Weight Lifting ◽  
Joint Torque ◽  
Maximum Weight ◽  
Angular Velocities ◽  
Asymmetric Lifting

In this study, the three-dimensional (3D) asymmetric maximum weight lifting is predicted using an inverse-dynamics-based optimization method considering dynamic joint torque limits. The dynamic joint torque limits are functions of joint angles and angular velocities, and imposed on the hip, knee, ankle, wrist, elbow, shoulder, and lumbar spine joints. The 3D model has 40 degrees of freedom (DOFs) including 34 physical revolute joints and 6 global joints. A multi-objective optimization (MOO) problem is solved by simultaneously maximizing box weight and minimizing the sum of joint torque squares. A total of 12 male subjects were recruited to conduct maximum weight box lifting using squat-lifting strategy. Finally, the predicted lifting motion, ground reaction forces, and maximum lifting weight are validated with the experimental data. The prediction results agree well with the experimental data and the model’s predictive capability is demonstrated. This is the first study that uses MOO to predict maximum lifting weight and 3D asymmetric lifting motion while considering dynamic joint torque limits. The proposed method has the potential to prevent individuals’ risk of injury for lifting.

THRESHOLD NEUTRAL PION PHOTOPRODUCTION ON THE PROTON AND THE CLOUDY BAG MODEL

1994 ◽  
Vol 09 (05) ◽  
pp. 399-409 ◽  
Author(s):  
A.N. TABACHENKO
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Electric Dipole ◽  
Neutral Pion ◽  
Chiral Symmetry Breaking ◽  
Additional Term ◽  
Pion Photoproduction ◽  
Differential Cross Sections ◽  
Neutral Pions ◽  
K Matrix

The energy dependence of the electric dipole amplitude, the total and differential cross-sections of the photoproduction of neutral pions off protons near threshold is given. The amplitude of process is a sum of the LET prediction and the additional term connected with the chiral symmetry breaking interaction. The simple K-matrix calculations are used to estimate the change in the electric dipole amplitude and the total and differential cross-sections between π0p and π+n thresholds.

Neutral pion photoproduction from the proton near threshold

1996 ◽  
Vol 368 (1-2) ◽  
pp. 20-25 ◽  
Author(s):  
M Fuchs ◽  
J Ahrens ◽  
G Anton ◽  
R Averbeck ◽  
R Beck ◽  
...  
Keyword(s):  
Neutral Pion ◽  
Pion Photoproduction ◽  
Near Threshold

scholarly journals Abelian anomaly and neutral pion production

2010 ◽  
Vol 82 (6) ◽  
Author(s):  
H. L. L. Roberts ◽  
C. D. Roberts ◽  
A. Bashir ◽  
L. X. Gutiérrez-Guerrero ◽  
P. C. Tandy
Keyword(s):  
Pion Production ◽  
Neutral Pion

Neutral Pion Photoproduction from Complex Nuclei Near Threshold

1979 ◽  
pp. 245-248
Author(s):  
F. L. Milder ◽  
E. C. Booth ◽  
B. L. Roberts ◽  
J. Comuzzi ◽  
H. Crannell
Keyword(s):  
Neutral Pion ◽  
Pion Photoproduction ◽  
Near Threshold ◽  
Complex Nuclei

scholarly journals POLARIZATION DEGREES OF FREEDOM IN CHARGED DOUBLE PION PRODUCTION BY VIRTUAL PHOTONS

GDH 2002 ◽  
2003 ◽  
Author(s):  
E. GOLOVACH ◽  
V. BURKERT ◽  
V. MOKEEV ◽  
M. RIPANI ◽  
M. ANGHINOLFI ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Pion Production ◽  
Virtual Photons ◽  
Double Pion

scholarly journals A three-dimensional musculoskeletal model of the dog

2020 ◽  
Author(s):  
Heiko Stark ◽  
Martin S. Fischer ◽  
Alexander Hunt ◽  
Fletcher Young ◽  
Roger Quinn ◽  
...  
Keyword(s):  
Experimental Data ◽  
Body Size ◽  
Degrees Of Freedom ◽  
Inverse Dynamics ◽  
Musculoskeletal Model ◽  
Muscle Synergy ◽  
Locomotor System ◽  
Wide Range ◽  
Joint Load

AbstractDogs are an interesting object of investigation because of the wide range of body size, body mass, and physique. In the last several years, the number of clinical and biomechanical studies on dog locomotion has increased. However, the relationship between body structure and joint load during locomotion, as well as between joint load and degenerative diseases of the locomotor system (e.g. dysplasia), are not sufficiently understood. In vivo measurements/records of joint forces and loads or deep/small muscles are complex, invasive, and sometimes ethically questionable. The use of detailed musculoskeletal models may help in filling that knowledge gap. We describe here the methods we used to create a detailed musculoskeletal model with 84 degrees of freedom and 134 muscles. Our model has three key-features: Three-dimensionality, scalability, and modularity. We tested the validity of the model by identifying forelimb muscle synergies of a beagle at walk. We used inverse dynamics and static optimization to estimate muscle activations based on experimental data. We identified three muscle synergy groups by using hierarchical clustering. Predicted activation patterns exhibited good agreement with experimental data for most of the forelimb muscles. We expect that our model will speed up the analysis of how body size, physique, agility, and disease influence joint neuronal control and loading in dog locomotion.

scholarly journals Diffractive Neutral Pion Production, Chiral Symmetry and the Odderon

2007 ◽  
Author(s):  
Carlo Ewerz ◽  
Otto Nachtmann
Keyword(s):  
Chiral Symmetry ◽  
Pion Production ◽  
Neutral Pion

Pion-nucleon interaction and neutral-pion photoproduction on the proton near threshold

1989 ◽  
Vol 40 (4) ◽  
pp. 1810-1813 ◽  
Author(s):  
Shin Nan Yang
Keyword(s):  
Neutral Pion ◽  
Pion Photoproduction ◽  
Nucleon Interaction ◽  
Pion Nucleon ◽  
Near Threshold

Neutral-pion production in central collisions of relativistic 12C and 40Ar on 208Pb

1985 ◽  
Vol 440 (4) ◽  
pp. 697-743 ◽  
Author(s):  
T. Hallman ◽  
J. Carroll ◽  
W. Dejarnrtte ◽  
E.K. McIntyre ◽  
L. Madansky ◽  
...  
Keyword(s):  
Pion Production ◽  
Neutral Pion ◽  
Central Collisions
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