Average multiplicity at high energies and renormalization group

1976 ◽  
Vol 33 (1) ◽  
pp. 195-204 ◽  
Author(s):  
W. Ernst ◽  
I. Schmitt
Keyword(s):  
Renormalization Group ◽  
Average Multiplicity ◽  
High Energies

Neutrinos and cosmological matter–antimatter asymmetry: A minimal seesaw with Frampton–Glashow–Yanagida ansatz

2017 ◽  
Vol 32 (16) ◽  
pp. 1742004
Author(s):  
Jue Zhang ◽  
Shun Zhou
Keyword(s):  
Renormalization Group ◽  
Low Energy ◽  
Neutrino Masses ◽  
Neutrino Mixing ◽  
High Energies ◽  
Seesaw Model ◽  
Mixing Parameters ◽  
Energy Neutrino ◽  
Flavor Mixing ◽  
Neutrino Experiments

In light of the latest neutrino data, we revisit a minimal seesaw model with the Frampton–Glashow–Yanagida ansatz. Renormalization-group running effects on neutrino masses and flavor mixing parameters are discussed and found to essentially have no impact on testing such a minimal scenario in low-energy neutrino experiments. However, since renormalization-group running can modify neutrino mixing parameters at high energies, it does affect the leptogenesis mechanism, which is responsible for the observed matter–antimatter asymmetry in our Universe. Furthermore, to ease the conflict between the naturalness argument and the successful leptogenesis, a special regime for resonant leptogenesis is also emphasized.

scholarly journals Predicting the SUSY breaking scale in SUGRA models with degenerate vacua

2020 ◽  
Vol 35 (01) ◽  
pp. 2050007
Author(s):  
C. D. Froggatt ◽  
R. Nevzorov ◽  
H. B. Nielsen ◽  
A. W. Thomas
Keyword(s):  
Renormalization Group ◽  
Energy Density ◽  
Vacuum Energy ◽  
Scalar Potential ◽  
Susy Breaking ◽  
Vacuum Energy Density ◽  
Second Phase ◽  
Dark Energy Density ◽  
High Energies ◽  
Breaking Scale

In [Formula: see text] supergravity, the scalar potential may have supersymmetric (SUSY) and nonsupersymmetric Minkowski vacua (associated with supersymmetric and physical phases) with vanishing energy density. In the supersymmetric Minkowski (second) phase, some breakdown of SUSY may be induced by nonperturbative effects in the observable sector that give rise to a tiny positive vacuum energy density. Postulating the exact degeneracy of the physical and second vacua as well as assuming that at high energies the couplings in both phases are almost identical, one can estimate the dark energy density in these vacua. It is mostly determined by the SUSY breaking scale [Formula: see text] in the physical phase. Exploring the two-loop renormalization group (RG) flow of couplings in these vacua, we find that the measured value of the cosmological constant can be reproduced if [Formula: see text] varies from 20 TeV to 400 TeV. We also argue that this prediction for the SUSY breaking scale is consistent with the upper bound on [Formula: see text] in the higgsino dark matter scenario.

Characteristics of the total disintegration events of emulsion heavy target nuclei caused by O16 and 28Si nuclei at high energies

2012 ◽  
Vol 90 (12) ◽  
pp. 1267-1278 ◽  
Author(s):  
Mahmoud Mohery
Keyword(s):  
Gaussian Distribution ◽  
Linear Dependence ◽  
Average Multiplicity ◽  
Secondary Particles ◽  
High Energies ◽  
Heavy Target ◽  
Inelastic Interactions ◽  
Free Hydrogen ◽  
Multiplicity Distributions ◽  
Fireball Model

The present paper deals with the interactions of 16O and 28Si nuclei with emulsion heavy target nuclei (silver (Ag) and bromine (Br)) at 4.5A GeV/c. The results have been analyzed to identify interesting characteristics of the total disintegration (TD) events produced in these interactions. Events having a number of heavily ionizing particles Nh ≥ 28 have been selected in this study. The integral multiplicity distributions for the disintegrated particles from the target nuclei have been used to separate the inelastic interactions with the free hydrogen (H), the light (CNO), and the heavy (AgBr) nuclei. The average multiplicities of the different secondary particles emitted in these interactions have been compared with the corresponding ones of different projectiles nearly at the same momentum. The average multiplicity of the grey particles is found to increase with the mass of the projectile, while the average multiplicity of the black particles is found to decrease with increasing mass of the projectile; this result agrees with the prediction of the fireball model. Also, the dependence of the shower, grey, and black particles produced in the TD events on the mass of the projectile has been studied. Moreover, the dependence of the probability of the TD for the projectile mass as well as the target fragments has also been discussed. The results show that the multiplicity distributions of the shower, grey, and black particles present a Gaussian distribution. Finally, the linear dependence of the grey and compound multiplicities on the black, heavy, and shower particles has also been observed.

Valence electron spectroscopy of inhomogeneous media

1992 ◽  
Vol 50 (2) ◽  
pp. 1150-1151
Author(s):  
A. Howie ◽  
D.W. McComb
Keyword(s):  
Specific Gravity ◽  
Loss Function ◽  
Electron Spectroscopy ◽  
Valence Electron ◽  
Peak Height ◽  
Loss Functions ◽  
Loss Peak ◽  
High Energies ◽  
Valence Electron Density ◽  
Electron Microscopist

The bulk loss function Im(-l/ε (ω)), a well established tool for the interpretation of valence loss spectra, is being progressively adapted to the wide variety of inhomogeneous samples of interest to the electron microscopist. Proportionality between n, the local valence electron density, and ε-1 (Sellmeyer's equation) has sometimes been assumed but may not be valid even in homogeneous samples. Figs. 1 and 2 show the experimentally measured bulk loss functions for three pure silicates of different specific gravity ρ - quartz (ρ = 2.66), coesite (ρ = 2.93) and a zeolite (ρ = 1.79). Clearly, despite the substantial differences in density, the shift of the prominent loss peak is very small and far less than that predicted by scaling e for quartz with Sellmeyer's equation or even the somewhat smaller shift given by the Clausius-Mossotti (CM) relation which assumes proportionality between n (or ρ in this case) and (ε - 1)/(ε + 2). Both theories overestimate the rise in the peak height for coesite and underestimate the increase at high energies.

Photon interactions at high energies

2001 ◽  
Vol 16 (1-2) ◽  
pp. 49-85
Author(s):  
A. De Roeck
Keyword(s):  
High Energies ◽  
Photon Interactions
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