Pole mass renormalon and its ramifications

I review the structure of the leading infrared renormalon divergence of the relation between the pole mass and the $$\overline{\mathrm{MS}}$$ MS ¯ mass of a heavy quark, with applications to the top, bottom and charm quark. That the pole quark mass definition must be abandoned in precision computations is a well-known consequence of the rapidly diverging series. The definitions and physics motivations of several leading renormalon-free, short-distance mass definitions suitable for processes involving nearly on-shell heavy quarks are discussed.

Re-thinking the Foundation of Physics and its Relation to Quantum Gravity and Quantum Probabilities: Unification of Gravity and Quantum Mechanics

In this paper we will show that standard physics to a large degree consists of derivatives of a deeper reality. This means standard physics is both overly complex and also incomplete. Modern physics has typically started from working with first understanding the surface of the world, that is typically the macroscopic world, and then forming theories about the atomic and subatomic world. And we did not have much of a choice, as the subatomic world is very hard to observe directly, if not impossible to observe directly at the deepest level. Despite the enormous success of modern physics, it is therefore no big surprise that we at some point have possibly taken a step in the wrong direction. We will claim that one such step came when one thought that the de Broglie wavelength represented a real matter wavelength. We will claim that the Compton wavelength is the real matter wavelength. Based on such a view we will see that many equations in modern physics are only derivatives of much simpler relations. Second, we will claim that in today’s physics one uses two different mass definitions, one mass definition that is complete or at least more complete, embedded in gravity equations without being aware of it, as it is concealed in GM, and the standard, but incomplete, kg mass definition in non-gravitational physics. First, when this is understood, and one uses the more complete mass definition that is embedded in gravity physics, not only in gravity physics, but in all of physics, then one has a chance to unify gravity and quantum mechanics. Our new theory shows that most physical phenomena when observed over a very short timescale are probabilistic for masses smaller than a Planck mass and dominated by determinism at or above Planck mass size. Our findings have many implications. For example, we show that the Heisenberg uncertainty principle is rooted in a foundation not valid for rest-mass particles, so the Heisenberg uncertainty principle can say nothing about rest-masses. When re-formulated based on a foundation compatible with a new momentum that is also compatible with rest-masses, we obtain a re-defined Heisenberg principle that seems to become a certainty principle in the special case of a Planck mass particle. Furthermore, we show that the Planck mass particle is linked to gravity and that we can easily detect the Planck scale from gravity observations. The Planck mass particle is unique as it only lasts the Planck time, and in that very short time period it can only be observed directly from itself, and it therefore closely linked to absolute rest.

On the Influence of the Mass Definition in the Stability of Axisymmetric Relativistic Thin Disks

Uno de los criterios más importantes para la caracterización de modelos galácticos o discos de acreción astrofísıcamente relevantes, es el análisis de la estabilidad de dichos modelos. En este trabajo, se realiza un análisis de la estabilidad de discos delgados estáticos relativistas con simetría axial, mediante la introduccón de una perturbación de primer orden en el tensor de energía-impulso del fluido. El formalismo se aplica a tres modelos construidos con el método de desplazamiento-corte-reflexión (DCR), previamente considerados en la literatura (Ujevicand Letelier, 2004), pero modificando el criterio de masa, es decir, usando la masa de Komar en lugar de la masa total superficial. Bajo estas condiciones, se encuentra que los valores de masa total son independientes de los parámetros del método DCR, lo que permite elegir la condición de frontera para el radio de corte que tome el valor máximo y a la vez permita una perturbación apreciable y bien comportada en el disco. Como resultado general, se encuentra que para la mayoría de modos de oscilación, la masa de Komar es más apropiada para definir el radio de corte.

Complex-Mass Definition and the Structure of Unstable Particle’s Propagator

The propagators of unstable particles are considered in framework of the convolution representation. Spectral function is found for a special case when the propagator of scalar unstable particle has Breit-Wigner form. The expressions for the dressed propagators of unstable vector and spinor fields are derived in an analytical way for this case. We obtain the propagators in modified Breit-Wigner forms which correspond to the complex-mass definition.

Relativistic rotation curve for cosmological structures

Using a general relativistic exact model for spherical structures in a cosmological background, we have put forward an algorithm to calculate the test particle geodesics within such cosmological structures in order to obtain the velocity profile of stars or galaxies. The rotation curve thus obtained is based on a density profile and is independent of any mass definition which is not unique in general relativity. It is then shown that this general relativistic rotation curves for a toy model and a NFW density profile are almost identical to the corresponding Newtonian one, although the general relativistic masses may be quite different.

The Impact of Low Muscle Mass Definition on the Prevalence of Sarcopenia in Older Australians

Background.Sarcopenia is the presence of low muscle mass and low muscle function. The aim of this study was to establish cutoffs for low muscle mass using three published methods and to compare the prevalence of sarcopenia in older Australians.Methods.Gender specific cutoffs levels were identified for low muscle mass using three different methods. Low grip strength was determined using established cutoffs of <30 kg for men and <20 kg for women to estimate the prevalence of sarcopenia.Results.Gender specific cutoffs levels for low muscle mass identified were (a) <6.89 kg/m2for men and <4.32 kg/m2for women, <2 standard deviation (SD) of a young reference population; (b) <7.36 kg/m2for men and <5.81 kg/m2for women from the lowest 20% percentile of the older group; and (c) <−2.15 for men and <−1.42 for women from the lowest 20% of the residuals of linear regressions of appendicular skeletal mass, adjusted for fat mass and height. Prevalence of sarcopenia in older (65 years and older) people by these three methods for men was 2.5%, 6.2%, and 6.4% and for women 0.3%, 9.3%, and 8.5%, respectively.Conclusions.Sarcopenia is common but consensus on the best method to confirm low muscle mass is required.

The Research Possibility of Definition Mass Biological Nanoobjects Using Terahertz Laser Ablation Method

Possibility of mass definition using terahertz laser ablation method for biological nanoobjects is researched. Diffusion spectrometer of aerosols was applied for measuring the size of dispersed products of terahertz laser ablation. Dependence of molecular mass from the aerosol particle size was obtained for fragments of DNA λ-hind. This work was carried out using THz radiation of free electron laser of Siberian center of photochemical researches.

GAUGE DEPENDENCE OF FERMION MASS RENORMALIZATION PRESCRIPTIONS

We discuss the gauge dependence of fermion mass definition under the on-shell and pole mass renormalization prescriptions. By the two-loop-level calculation of the cross section of the physical process [Formula: see text], we prove for the first time that the on-shell fermion mass renormalization prescription makes physical result gauge-dependent. On the other hand, such gauge dependence does not appear in the result of the pole mass renormalization prescription. Our calculation also implies that the difference of physical results between the two mass renormalization prescriptions cannot be neglected at two-loop level.