scholarly journals QUARK STRUCTURE OF PSEUDOSCALAR MESONS

2000 ◽  
Vol 15 (02) ◽  
pp. 159-207 ◽  
Author(s):  
THORSTEN FELDMANN
Keyword(s):  
High Energy ◽  
Wave Functions ◽  
Low Energy ◽  
Mixing Process ◽  
Chiral Perturbation ◽  
Fock States ◽  
Mixing Parameters ◽  
Pseudoscalar Mesons ◽  
Energy Application ◽  
Quark Structure

I review to which extent the properties of pseudoscalar mesons can be understood in terms of the underlying quark (and eventually gluon) structure. Special emphasis is put on the progress in our understanding of η–η′ mixing. Process-independent mixing parameters are defined, and relations between different bases and conventions are studied. Both, the low-energy description in the framework of chiral perturbation theory and the high-energy application in terms of light-cone wave functions for partonic Fock states, are considered. A thorough discussion of theoretical and phenomenological consequences of the mixing approach will be given. Finally, I will discuss mixing with other states (π0, ηc, …).

scholarly journals The low-energy effective theory of axions and ALPs

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Martin Bauer ◽  
Matthias Neubert ◽  
Sophie Renner ◽  
Marvin Schnubel ◽  
Andrea Thamm
Keyword(s):  
High Energy ◽  
New Physics ◽  
Mass Scale ◽  
Low Energy ◽  
Effective Theory ◽  
Loop Order ◽  
Flavor Changing ◽  
Effective Lagrangian ◽  
Anomalous Dimensions ◽  
Pseudoscalar Mesons

Abstract Axions and axion-like particles (ALPs) are well-motivated low-energy relics of high-energy extensions of the Standard Model, which interact with the known particles through higher-dimensional operators suppressed by the mass scale Λ of the new-physics sector. Starting from the most general dimension-5 interactions, we discuss in detail the evolution of the ALP couplings from the new-physics scale to energies at and below the scale of electroweak symmetry breaking. We derive the relevant anomalous dimensions at two-loop order in gauge couplings and one-loop order in Yukawa interactions, carefully considering the treatment of a redundant operator involving an ALP coupling to the Higgs current. We account for one-loop (and partially two-loop) matching contributions at the weak scale, including in particular flavor-changing effects. The relations between different equivalent forms of the effective Lagrangian are discussed in detail. We also construct the effective chiral Lagrangian for an ALP interacting with photons and light pseudoscalar mesons, pointing out important differences with the corresponding Lagrangian for the QCD axion.

Computed Tomography Experiments on a Laboratory Multipurpose Diffractometer

2017 ◽  
Vol 742 ◽  
pp. 666-670
Author(s):  
Natalia Dadivanyan ◽  
Detlev J. Götz ◽  
Detlef Beckers ◽  
Fabio Masiello
Keyword(s):  
Computed Tomography ◽  
Heavy Element ◽  
High Energy ◽  
Low Energy ◽  
Qualitative And Quantitative Analysis ◽  
X Ray ◽  
Qualitative And Quantitative ◽  
Energy Application ◽  
Solid Compounds ◽  
3D Information

Applications of soft (Co and Cu X-ray tube) and hard (Ag X-ray tube) radiation in computed tomography experiments on a laboratory X-ray diffractometer are presented. Using low energy (<10 keV) X-ray sources provide the possibility to investigate objects made of light (organic) materials in more detail compared to the high energy application. In case of metal or heavy element containing composites high energy (~20 keV) X-ray sources allow to obtain full 3D information on the samples without destroying them. These measurements allow both qualitative and quantitative analysis of porous materials, samples with oriented components, and solid compounds.

Pretreatment with low‐energy (12 kV) shockwave lithotripsy (SWL) protects kidney from subsequent high‐energy application

2001 ◽  
Vol 109 (5) ◽  
pp. 2480-2480
Author(s):  
Andrew Evan ◽  
Lynn Willis ◽  
Bret Connors ◽  
Philip Blomgren ◽  
Youzhi Shao ◽  
...  
Keyword(s):  
High Energy ◽  
Low Energy ◽  
Shockwave Lithotripsy ◽  
Energy Application

IS THE CRONIN’S REPRESENTATION CORRECT FOR THE PENGUIN OPERATOR?

1992 ◽  
Vol 07 (05) ◽  
pp. 427-435 ◽  
Author(s):  
A.N. IVANOV ◽  
M. NAGY ◽  
N.I. TROITSKAYA
Keyword(s):  
Wave Functions ◽  
Low Energy ◽  
Energy Limit ◽  
Chiral Perturbation ◽  
K Meson ◽  
Chiral Transformation ◽  
Quark Level ◽  
Penguin Operator ◽  
Hadronic Level

It is shown that the Cronin’s operator, being used for a phenomenological description of non-loptonic K-meson decays within the effective chiral Lagrangian approach with non-linear realization of chiral SU (3)× SU (3) symmetry (so-called, chiral perturbation theory at the hadronic level), cannot be applied to the determination of the Penguin-operator (O5-operator) at the hadronic level. The affirmation is based on the proof of the violation of the low-energy theorem [Formula: see text] which is valid within the framework of the Cronin’s representation. The violation of this low-energy theorem is obtained at the quark level and connected with the account of the low-energy interactions of pions caused by the overlap of wave functions of pions in the |π+π−> state in the low-energy limit p+→0. The chiral transformation properties of the normal-ordered Penguin operator are studied.

scholarly journals Origin of Low- and High-Energy Monopole Collectivity in 132Sn

Universe ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. 145
Author(s):  
Nikolay N. Arsenyev ◽  
Alexey P. Severyukhin
Keyword(s):  
Experimental Data ◽  
Excited States ◽  
Lower Energy ◽  
High Energy ◽  
Wave Functions ◽  
Low Energy ◽  
Phonon Coupling ◽  
Skyrme Interaction ◽  
Separable Approximation ◽  
Hole Interaction

Beginning with the Skyrme interaction, we study the properties of the isoscalar giant monopole resonances (ISGMR) of 132Sn. Using the finite-rank separable approximation for the particle-hole interaction, the coupling between one- and two-phonon terms in the wave functions of excited states is taken into account in very large configurational spaces. The inclusion of the phonon–phonon coupling (PPC) results in the formation of a low-energy 0+ state. The PPC inclusion leads to a fragmentation of the ISGMR strength to lower energy states and also to a higher energy tail. Using the same set of parameters, we describe the available experimental data for the ISGMR characteristics of 118,120,122,124Sn and give a prediction for 126,128,130,132Sn.

scholarly journals RENORMALIZATION GROUP EVOLUTION OF NEUTRINO MASSES AND MIXING IN SEESAW MODELS

2010 ◽  
Vol 25 (23) ◽  
pp. 4339-4384 ◽  
Author(s):  
SHAMAYITA RAY
Keyword(s):  
Renormalization Group ◽  
High Energy ◽  
Energy Scale ◽  
Low Energy ◽  
Effective Theory ◽  
Neutrino Masses ◽  
Mixing Parameters ◽  
Group Evolution ◽  
High Energy Scale ◽  
The Masses

We consider different extensions of the Standard Model which can give rise to the small active neutrino masses through seesaw mechanisms, and their mixing. These tiny neutrino masses are generated at some high energy scale by the heavy seesaw fields which then get sequentially decoupled to give an effective dimension-5 operator at the low energy. The renormalization group evolution of the masses and the mixing parameters of the three active neutrinos in the high energy as well as the low energy effective theory is reviewed in this paper.

scholarly journals Two-meson form factors in unitarized chiral perturbation theory

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Yu-Ji Shi ◽  
Chien-Yeah Seng ◽  
Feng-Kun Guo ◽  
Bastian Kubis ◽  
Ulf-G. Meißner ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Form Factors ◽  
Low Energy ◽  
Beyond The Standard Model ◽  
Chiral Perturbation ◽  
Leptonic Decays ◽  
Pseudoscalar Mesons ◽  
Lepton Decay ◽  
Scattering Phase

Abstract We present a comprehensive analysis of form factors for two light pseudoscalar mesons induced by scalar, vector, and tensor quark operators. The theoretical framework is based on a combination of unitarized chiral perturbation theory and dispersion relations. The low-energy constants in chiral perturbation theory are fixed by a global fit to the available data of the two-meson scattering phase shifts. Each form factor derived from unitarized chiral perturbation theory is improved by iteratively applying a dispersion relation. This study updates the existing results in the literature and explores those that have not been systematically studied previously, in particular the two-meson tensor form factors within unitarized chiral perturbation theory. We also discuss the applications of these form factors as mandatory inputs for low-energy phenomena, such as the semi-leptonic decays Bs→ π+π−ℓ+ℓ− and the τ lepton decay τ → π−π0ντ, in searches for physics beyond the Standard Model.

Low energy vs. high energy depositional settings and related sedimentary bodies in early Senenian rudist bearing carbonate shelves (central-southern Italy)

2001 ◽  
Vol 28 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Gabriele Carannante ◽  
A. Laviano ◽  
D. Ruberti ◽  
Lucia Simone ◽  
G. Sirna ◽  
...  
Keyword(s):  
Southern Italy ◽  
High Energy ◽  
Low Energy ◽  
Depositional Settings

Transportation: Fuel Energies

2017 ◽  
Author(s):  
Peter Rez
Keyword(s):  
Energy Density ◽  
Fossil Fuels ◽  
High Energy ◽  
Ease Of Use ◽  
Low Energy ◽  
High Energy Density ◽  
Nuclear Fuels ◽  
Liquid Hydrocarbons ◽  
Transportation Fuel ◽  
Journey Time

Transportation efficiency can be measured in terms of the energy needed to move a person or a tonne of freight over a given distance. For passengers, journey time is important, so an equally useful measure is the product of the energy used and the time taken for the journey. Transportation requires storage of energy. Rechargeable systems such as batteries have very low energy densities as compared to fossil fuels. The highest energy densities come from nuclear fuels, although, because of shielding requirements, these are not practical for most forms of transportation. Liquid hydrocarbons represent a nice compromise between high energy density and ease of use.

scholarly journals Low-Energy Electron Damage to Condensed-Phase DNA and Its Constituents

2021 ◽  
Vol 22 (15) ◽  
pp. 7879
Author(s):  
Yingxia Gao ◽  
Yi Zheng ◽  
Léon Sanche
Keyword(s):  
Condensed Phase ◽  
Genetic Material ◽  
High Energy ◽  
Dna Lesions ◽  
Low Energy ◽  
Experimental Investigations ◽  
Experimental Conditions ◽  
Strand Breaks ◽  
Sequence Of Events ◽  
Wide Range

The complex physical and chemical reactions between the large number of low-energy (0–30 eV) electrons (LEEs) released by high energy radiation interacting with genetic material can lead to the formation of various DNA lesions such as crosslinks, single strand breaks, base modifications, and cleavage, as well as double strand breaks and other cluster damages. When crosslinks and cluster damages cannot be repaired by the cell, they can cause genetic loss of information, mutations, apoptosis, and promote genomic instability. Through the efforts of many research groups in the past two decades, the study of the interaction between LEEs and DNA under different experimental conditions has unveiled some of the main mechanisms responsible for these damages. In the present review, we focus on experimental investigations in the condensed phase that range from fundamental DNA constituents to oligonucleotides, synthetic duplex DNA, and bacterial (i.e., plasmid) DNA. These targets were irradiated either with LEEs from a monoenergetic-electron or photoelectron source, as sub-monolayer, monolayer, or multilayer films and within clusters or water solutions. Each type of experiment is briefly described, and the observed DNA damages are reported, along with the proposed mechanisms. Defining the role of LEEs within the sequence of events leading to radiobiological lesions contributes to our understanding of the action of radiation on living organisms, over a wide range of initial radiation energies. Applications of the interaction of LEEs with DNA to radiotherapy are briefly summarized.

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