scholarly journals Production of Hypernuclei by Antiprotons

2018 ◽  
Vol 181 ◽  
pp. 01026
Author(s):  
Horst Lenske ◽  
Alexei Larionov
Keyword(s):  
Cross Sections ◽  
Production Cross ◽  
Beam Momentum ◽  
Wave Functions ◽  
Meson Exchange ◽  
Momentum Dependence ◽  
Final State ◽  
Final State Interactions ◽  
Pseudo Scalar ◽  
First Time

The production of hypernuclei is investigated for p̅+A→Λ‾+ΛA reactions in a covariant meson exchange approach. Besides the conventional pseudo-scalar (K) and vector (K*) channels, we study for the first time also contributions from the correlated πK scalar channel, described by the k/K*0 meson. Initial and final state interactions are considered by eikonal theory. The total and angular differential cross sections of the coherent process p̅+AZ→ΛA(Z−1)+Λ̅ are evaluated at the beam momenta 1:5…20 GeV/c within the meson exchange model with bound proton and Λ-hyperon wave functions. It is shown that the shape of the beam momentum dependence of the hypernucleus production cross sections with various discrete Λ states is strongly sensitive to the presence of the scalar k meson exchange in the p̅p→Λ̅Λ amplitude. This can be used as a clean test of the exchange by scalar πK correlation in coherent p̅A reactions.

scholarly journals Collinear expansion for color singlet cross sections

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Markus A. Ebert ◽  
Bernhard Mistlberger ◽  
Gherardo Vita
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Production Cross ◽  
Gluon Fusion ◽  
Building Blocks ◽  
Color Singlet ◽  
Final State ◽  
Beam Function ◽  
Kinematic Limit ◽  
State Radiation

Abstract We demonstrate how to efficiently expand cross sections for color-singlet production at hadron colliders around the kinematic limit of all final state radiation being collinear to one of the incoming hadrons. This expansion is systematically improvable and applicable to a large class of physical observables. We demonstrate the viability of this technique by obtaining the first two terms in the collinear expansion of the rapidity distribution of the gluon fusion Higgs boson production cross section at next-to-next-to leading order (NNLO) in QCD perturbation theory. Furthermore, we illustrate how this technique is used to extract universal building blocks of scattering cross section like the N-jettiness and transverse momentum beam function at NNLO.

scholarly journals EXTRACTION OF RESONANCE PARAMETERS AND ROLE OF THE FINAL STATE INTERACTIONS

2014 ◽  
Vol 26 ◽  
pp. 1460082 ◽  
Author(s):  
IGOR I. STRAKOVSKY ◽  
WILLIAM J. BRISCOE ◽  
ALEXANDER E. KUDRYAVTSEV ◽  
VLADIMIR E. TARASOV
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Impulse Approximation ◽  
Pion Photoproduction ◽  
Final State ◽  
The World ◽  
Final State Interactions ◽  
Watson’S Theorem ◽  
Photoproduction Data

We present an overview of the SAID group effort to analyze new γn → π-p cross sections vs. the world database to get new multipoles and determine neutron electromagnetic couplings. The differential cross section for the processes γn → π-p was extracted from new measurements at CLAS and MAMI-B accounting for Fermi motion effects in the impulse approximation (IA) as well as NN- and πN-FSI effects beyond the IA. We evaluated results of several pion photoproduction analyses and compared πN PWA results as a constraint for analyses of pion photoproduction data (Watson's theorem).

STUDY OF MESON PRODUCTION IN NUCLEI NEAR THRESHOLD

2009 ◽  
Vol 18 (05n06) ◽  
pp. 1271-1281 ◽  
Author(s):  
B. K. JAIN ◽  
N. J. UPADHYAY ◽  
K. P. KHEMCHANDANI ◽  
N. G. KELKAR
Keyword(s):  
Cross Sections ◽  
Final State Interaction ◽  
Scattering Length ◽  
Meson Production ◽  
Final State ◽  
Total Cross Sections ◽  
Low Energies ◽  
Final State Interactions ◽  
T Matrix ◽  
Near Threshold

We present a study of the η production at low energies in pd collision with 3He and pd nuclear systems in the final state. The η production mechanism is described by a two-step model and the final state interactions are included fully. The η - d and η - 3He final state interactions are incorporated through the solution of the Lippmann Schwinger equation for a half off-shell η - AT-matrix. For η - d this t -matrix is written in a factorized form, with an off-shell form factor multiplying an on-shell part having the scattering length representation. The p - d final state interaction is included by multiplying the production matrix element by the inverse of the Jost function which includes the strong as well as the Coulomb interaction. The total cross sections are found to be strongly affected by both the η - d and the p - d final state interactions. The η - 3HeT-matrix is obtained in the Finite Rank Approximation (FRA) by solving few-body equations. The calculated total cross sections are in good accord with the available experimental data. Through the time delay method of Wigner, we also explore the possibility of the existence of quasi-bound η-3 He mesic states in this η - 3He T -matrix. We find that the T -matrix which reproduces the low energy pd → 3He η data implies a quasi-bound eta state near threshold. This is in accord with experimental indications.

scholarly journals HIGHER TWIST EFFECTS IN PHOTON–PHOTON COLLISIONS

2008 ◽  
Vol 17 (06) ◽  
pp. 1041-1059 ◽  
Author(s):  
A. I. AHMADOV ◽  
I. BOZTOSUN ◽  
A. SOYLU ◽  
E. A. DADASHOV
Keyword(s):  
Wave Function ◽  
Cross Section ◽  
Cross Sections ◽  
Production Cross ◽  
Wave Functions ◽  
Feynman Diagrams ◽  
High Twist ◽  
Higher Twist Effects ◽  
Two Photon ◽  
Pion Wave Function

In this article, we investigate the contribution of the high twist Feynman diagrams to the large-pT single pseudoscalar and vector mesons inclusive production cross section in two-photon collisions and we present the general formulae for the high and leading twist differential cross sections. The pion wave function where two non-trivial Gegenbauer coefficients a2 and a4 have been extracted from the CLEO data, Braun–Filyanov pion wave function, the asymptotic and the Chernyak–Zhitnitsky wave functions are all used in the calculations. For ρ-meson we used the Ball–Braun wave function. The results of the calculations reveal that the high twist cross sections, the ratio R, the dependence transverse momentum pT and the rapidity y of meson in the Φ CLEO (x, Q2) wave function case is very close to the Φ asy (x) asymptotic wave function case. It is shown that the high twist contribution to the cross section depends on the choice of the meson wave functions.

First-order exchange approximation

1963 ◽  
Vol 276 (1366) ◽  
pp. 346-353 ◽  
Keyword(s):  
Elastic Scattering ◽  
Cross Sections ◽  
Born Approximation ◽  
Scattering Amplitude ◽  
Wave Functions ◽  
Hydrogen Atoms ◽  
Final State ◽  
First Order ◽  
Exchange Approximation ◽  
Exchange Scattering

It is shown that when the Born approximation is applied to rearrangement collisions in the customary way, terms of the first order in the interaction energy between the colliding particles are omitted from the exchange scattering amplitude. If these terms are retained the arbitrariness which arises from the lack of orthogonality between the initial and final state wave functions is removed. The first-order exchange approximation derived in the present paper is employed to calculate the cross-sections for the 1 s -2 s and 1 s -2 p excitations of hydrogen atoms by electron impact and the elastic scattering of electrons by hydrogen atoms.

EQUAL VELOCITY RULE IN HEAVY HADRON PRODUCTION AT HIGH ENERGY

1989 ◽  
Vol 04 (02) ◽  
pp. 369-387 ◽  
Author(s):  
T. KITAZOE ◽  
H. INAZAWA ◽  
T. MORII
Keyword(s):  
Cross Sections ◽  
Particle Production ◽  
Production Cross ◽  
Heavy Particle ◽  
Bound State ◽  
High Energy ◽  
Wave Functions ◽  
Characteristic Energy ◽  
Heavy Particles ◽  
Heavy Hadron

A production mechanism of heavy particles in e+e− annihilations is studied on a field theoretical basis using the bound state wave functions. The requirement that wave functions of hadrons overlap maximally with each other leads to the conclusion that (1) the model predicts a 2-jet structure in a one-loop diagram and (2) heavy hadrons in a jet have an equal velocity. Heavy particle production cross sections and their characteristic energy distributions are calculated for some typical reactions.

scholarly journals FLAVOR DEPENDENCE OF UNPOLARIZED TMDS FROM SEMI-INCLUSIVE PION PRODUCTION

2014 ◽  
Vol 25 ◽  
pp. 1460020 ◽  
Author(s):  
ANDREA SIGNORI ◽  
ALESSANDRO BACCHETTA ◽  
MARCO RADICI
Keyword(s):  
Transverse Momentum ◽  
Pion Production ◽  
Distribution Functions ◽  
Momentum Dependence ◽  
Parton Distribution Functions ◽  
Final State ◽  
Fragmentation Functions ◽  
First Time ◽  
Better Than ◽  
Independent Model

Recent data from semi-inclusive deep inelastic scattering collected by the HERMES collaboration allow for the first time to discuss how the transverse-momentum dependence of unpolarized distribution and fragmentation functions is affected by the flavor of the involved partons. A model built with flavor-dependent Gaussian transverse-momentum distributions fits data better than the same flavor-independent model. The current analysis is performed for totally unpolarized scattering of leptons off protons and deuterons, with detected pions in the final state. There are convincing indications of flavor dependence in the fragmentation functions, while for parton distribution functions the evidence is weaker.

Influence of final-state interaction on double spin asymmetries in incoherent π+-photoproduction on the deuteron near threshold

2020 ◽  
Vol 29 (08) ◽  
pp. 2050056
Author(s):  
E. M. Darwish ◽  
H. M. Al-Ghamdi
Keyword(s):  
Cross Sections ◽  
Energy Region ◽  
Final State Interaction ◽  
Reaction Model ◽  
Final State ◽  
Total Cross Sections ◽  
Spin Asymmetries ◽  
Double Spin ◽  
Final State Interactions ◽  
Near Threshold

Incoherent [Formula: see text]-photoproduction on the deuteron is investigated for photon energies near threshold with particular focus on beam-target double spin asymmetries. The analysis is based on a [Formula: see text] reaction model in which realistic elementary amplitudes for [Formula: see text], [Formula: see text] and [Formula: see text] are incorporated. Numerical results on all possible beam-target double spin asymmetries of the differential and total cross-sections in the photon energy region near threshold are presented. Effects of [Formula: see text] and [Formula: see text] final-state interactions are investigated and their roles are found to be important.

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