scholarly journals K±→π±π0e+e−decay width calculation in the lepton center-of-mass system

2014 ◽  
Vol 81 ◽  
pp. 05014
Author(s):  
S. R. Gevorkyan ◽  
M. H. Misheva
Keyword(s):  
Decay Width ◽  
Center Of Mass ◽  
Mass System

HELICITY AMPLITUDES FOR COLLIDING BEAM SCATTERING OF TWO SPIN 1/2 PARTICLES

1993 ◽  
Vol 08 (30) ◽  
pp. 5383-5407
Author(s):  
T.B. ANDERS ◽  
A.O. BARUT ◽  
W. JACHMANN
Keyword(s):  
Center Of Mass ◽  
Mass System ◽  
Intermediate Transformation ◽  
Beam System ◽  
Pair Annihilation ◽  
Helicity Amplitudes ◽  
Reaction Channels ◽  
Invariant Coupling ◽  
Exchange Scattering ◽  
The One

As a generalization and extension of the extensive tables of polarization asymmetries given in a previous work,1 we present here tables of helicity amplitudes for the scattering of two spin 1/2 particles in the colliding beam system (i.e. two incoming particles with opposite directions but not necessarily of equal momenta). The particles belonging to the same current may have different masses in order to describe particle excitations. The amplitudes are given for six different basic couplings connecting two vector vertices, a vector vertex at the one current and a derivative vector vertex at the other current, two derivative vector vertices, two tensor vertices, and two scalar vertices. The vertices include axial couplings by factors of type 1+cγ5. The amplitudes are written as expressions with 16 components in the six different reaction channels, namely the scattering of two fermions, of two antifermions, and of a fermion and an antifermion, the pair creation by pair annihilation, as well as the exchange scattering for two identical fermions or antifermions. The formulas may be used for an analysis which extracts the invariant coupling functions from the experimental data obtained in the colliding beam system directly without an intermediate transformation to the center of mass system.

Inclusive Single-Particle Production at 90° in the Center-of-Mass System for Nuclear Targets and 28.5-GeV/cIncident Protons

1976 ◽  
Vol 37 (26) ◽  
pp. 1731-1734 ◽  
Author(s):  
U. Becker ◽  
J. Burger ◽  
M. Chen ◽  
G. Everhart ◽  
F. H. Heimlich ◽  
...  
Keyword(s):  
Single Particle ◽  
Particle Production ◽  
Center Of Mass ◽  
Mass System ◽  
Nuclear Targets

scholarly journals Testing Compound Nucleus Hypothesis Across the 17O Nucleus Excitation

2019 ◽  
Vol 211 ◽  
pp. 02001 ◽  
Author(s):  
Aloys Nizigama ◽  
Pierre Tamagno ◽  
Olivier Bouland
Keyword(s):  
Cross Section ◽  
Compound Nucleus ◽  
Cross Sections ◽  
Center Of Mass ◽  
Ground States ◽  
Mass System ◽  
Resonance Parameters ◽  
Second Stage ◽  
Reference Framework ◽  
Kinetic Transformation

The excited compound nucleus 17O* has been studied over (n,α) and (α,n) cross sections modelling, respectively for 16O and 13C targets in their ground states. The modelling is fulfilled within the Reich-Moore formalism. We were able to calculate the (α,n) cross section by two separate ways: the direct kinematic standard route and by inversion of the (n,α) cross section using the compound nucleus hypothesis. Resonance parameters of the resolved resonance range (0 to 6 MeV) were borrowed from the CIELO project. In a first stage, the modelling is carried out in the referential of the incident particle (either way neutron or α) requesting conversion of the CIELO neutron-type resonance parameters to the α-type. In a second stage, the implementation is uniquely designed in the center of mass system of the excited compound nucleus. The resonance parameters are thus converted in that unique reference framework. The present investigation shows the consistency of the kinetic transformation that relies on the compound nucleus hypothesis.

scholarly journals Estimation of leg stiffness using an approximation to the planar spring–mass system in high-speed running

2020 ◽  
Vol 17 (1) ◽  
pp. 172988141989071
Author(s):  
Wei Guo ◽  
Changrong Cai ◽  
Mantian Li ◽  
Fusheng Zha ◽  
Pengfei Wang ◽  
...  
Keyword(s):  
Analytical Solution ◽  
High Speed ◽  
Stance Phase ◽  
Center Of Mass ◽  
Critical Role ◽  
Line Center ◽  
Motion Model ◽  
Mass System ◽  
Leg Stiffness ◽  
Wide Range

Leg stiffness plays a critical role in legged robots’ speed regulation. However, the analytic solutions to the differential equations of the stance phase do not exist, of course not for the exact analytical solution of stiffness. In view of the challenge in dealing with every circumstance by numerical methods, which have been adopted to tabulate approximate answers, the “harmonic motion model” was used as approximation of the stance phase. However, the wide range leg sweep angles and small fluctuations of the “center of mass” in fast movement were overlooked. In this article, we raise a “triangle motion model” with uniform forward speed, symmetric movement, and straight-line center of mass trajectory. The characters are then shifted to a quadratic equation by Taylor expansion and obtain an approximate analytical solution. Both the numerical simulation and ADAMS-Matlab co-simulation of the control system show the accuracy of the triangle motion model method in predicting leg stiffness even in the ultra-high-speed case, and it is also adaptable to low-speed cases. The study illuminates the relationship between leg stiffness and speed, and the approximation model of the planar spring–mass system may serve as an analytical tool for leg stiffness estimation in high-speed locomotion.

Counting of oscillatory modes of valence quarks forming qqq baryons for three quark flavors u, d, s

2017 ◽  
Vol 32 (04) ◽  
pp. 1750004 ◽  
Author(s):  
Sonia Kabana ◽  
Peter Minkowski
Keyword(s):  
Field Theory ◽  
Finite Number ◽  
Center Of Mass ◽  
Rotation Group ◽  
Broken Symmetry ◽  
Mass System ◽  
Angular Momenta ◽  
Space Rotation ◽  
Three Space ◽  
Quark Flavors

We present the unique properties of oscillatory modes of [Formula: see text] light quarks — [Formula: see text], [Formula: see text], [Formula: see text] — using the [Formula: see text] broken symmetry classification. [Formula: see text] stands for the space rotation group generated by the sum of the three individual angular momenta of quarks in their c.m. system. The baryonic multiplets are shown to emerge from the picture of oscillating quarks in three space dimensions in the center-of-mass system of the baryons. All oscillatory modes are fully relativistic with a finite number of oscillators and this is forming the unique harmonic oscillator with these properties. The density of states as a function of mass-square is calculated. This estimate is of relevance for the accounting of the missing states of unobserved hadrons, as the here estimated baryonic multiplets include both the observed and the unobserved (or “missing”) hadrons. The estimate is conceptually different from Hagedorn’s model and is based on field theory of QCD.

DESCRIPTION OF (PSEUDO-)RAPIDITY DENSITY AND TRANSVERSE MOMENTUM DISTRIBUTIONS IN A WIDE ENERGY RANGE $(\sqrt{s} = 22.4\hbox{--}7000~{\rm GeV})$

2012 ◽  
Vol 27 (09) ◽  
pp. 1250043 ◽  
Author(s):  
AKINORI OHSAWA ◽  
EDISON HIROYUKI SHIBUYA ◽  
MASANOBU TAMADA
Keyword(s):  
Transverse Momentum ◽  
Energy Dependence ◽  
Particle Production ◽  
Center Of Mass ◽  
Wide Energy Range ◽  
Charged Multiplicity ◽  
Mass System ◽  
Rapidity Density ◽  
Momentum Distributions ◽  
Multiple Particle Production

The rapidity density and transverse momentum distributions of produced particles in multiple particle production are formulated assuming that the produced particles are emitted isotropically from several emitting centers. The energy distribution of produced particles in the rest frames of respective emitting centers is that of the Tsallis statistics. The distribution of emitting centers is flat with slanting cuts at both shoulders on the rapidity axis in the center of mass system. The formulation includes six adjustable parameters, among which four are energy dependent and more important and are determined so that the transverse momentum and the (pseudo-)rapidity density distributions fit to the data at various energies. The energy dependences of the four parameters, determined empirically, reproduce quite well the energy dependence of the average transverse momentum, that of the pseudo-rapidity density at η* = 0 and that of the charged multiplicity. The energy dependence of the inelasticity is either increasing or decreasing from the assumed value of K = 0.5 at [Formula: see text], due to lack of experimental data at the most-forward rapidity region. The pseudo-rapidity density distribution at LHC energy [Formula: see text] expected by the present formulation is compared with those by the other models.

I = 2S-wave pion scattering phase shift with two flavor full QCD

2005 ◽  
Vol 20 (15) ◽  
pp. 3476-3479
Author(s):  
◽  
T. Yamazaki
Keyword(s):  
Phase Shift ◽  
Center Of Mass ◽  
Laboratory System ◽  
Lattice Calculation ◽  
S Wave ◽  
Mass System ◽  
Pion Scattering ◽  
Scattering Phase ◽  
Volume Method ◽  
The Continuum

We present a lattice calculation of the scattering phase shift for the I = 2 S -wave pion-pion system in the continuum limit with two-flavor dynamical effect. Calculations are made at three lattice spacings, using the finite volume method proposed by Lüscher in the center of mass system, and its extension to the laboratory system by Rummukainen and Gottlieb.

THE REACTION D(p, γ)He3 BELOW 50 KEV

1963 ◽  
Vol 41 (5) ◽  
pp. 724-736 ◽  
Author(s):  
G. M. Griffiths ◽  
M. Lal ◽  
C. D. Scarfe
Keyword(s):  
Angular Distribution ◽  
Cross Sections ◽  
Center Of Mass ◽  
P Wave ◽  
Laboratory System ◽  
S Wave ◽  
Mass System ◽  
S Factor ◽  
Low Energies ◽  
Γ Rays

The yield and angular distribution of the γ rays from the reaction D(p, γ) He3 have been measured with thick heavy-ice targets in the energy range from 24 kev to 48 kev. Assuming a simplified energy dependence the results have been analyzed to give cross sections for p-wave and s-wave capture. At 25 kev in the laboratory system, the cross sections are[Formula: see text]The astrophysical S-factors in the center-of-mass system below 40 kev have been found to be[Formula: see text]for E in center-of-mass kilovolts and[Formula: see text]independent of energy giving a total S-factor for low energies[Formula: see text]with E in center-of-mass kilovolts.

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