Nuclear Theory·nucl-th

Monday·May 20, 2019

4 papers—1 primary·3 cross-listed

01
Transport coefficients for multi-component gas of hadrons using Chapman Enskog method
Ashutosh Dash🇮🇳 · Subhasis Samanta🇮🇳 · Bedangadas Mohanty🇮🇳
The transport coefficients of a multi-component hadronic gas at zero and non-zero baryon chemical potential are calculated using the Chapman-Enskog method. The calculations are done within the framework of an $S$ -matrix based interacting hadron resonance gas model. In this model, the phase-shifts and cross-sections are calculated using $K$ -matrix formalism and where required, by parameterizing the experimental phase-shifts. Using the energy dependence of cross-section, we find the temperature dependence of various transport coefficients such as shear viscosity, bulk viscosity, heat conductivity and diffusion coefficient. We finally compare our results regarding various transport coefficients with previous results in the literature.
nucl-thhep-phPRD(2019)·13 citations
02
A new combined analysis of elastic and charge exchange $K N (K ˉ N)$ scatterings in the Regge realm
Byung-Geel Yu🇰🇷 · Kook-Jin Kong🇰🇷
The Regge features of elastic $K^{\pm} N \to K^{\pm} N$ , and charge exchange $K^{-} p \to K ˉ^{0} n$ and $K^{+} n \to K^{0} p$ reactions are described by using a combined analysis of all these channels at high momenta. Based on the meson exchanges in the $t$ -channel with their decays to $K K ˉ$ pair allowed, the exchanges of $ρ (775) + ω (782)$ are excluded in contrast to existing model calculations and the present work follows a new scheme for the meson exchanges $a_{0} (980) + ϕ (1020) + f_{2} (1275) + a_{2} (1320)$ reggeized for the forward elastic scattering amplitude together with Pomeron. The charge exchange reactions are described by $a_{0} (980) + a_{2} (1320)$ exchanges in the $t$ -channel. Dominance of the isoscalar $f_{2}$ and Pomeron exchanges beyond $P_{Lab} \approx 3$ GeV/ $c$ is shown in the elastic process. Both the isovector $a_{0}$ and $a_{2}$ exchanges in charge exchange reactions play the respective roles in the low and high momentum region. Differential and total cross sections are presented to compare with existing data. Discussion is given to the polarization of $K^{-} p \to K^{-} p$ at $P_{L ab} = 10$ GeV/ $c$ and $K^{-} p \to K ˉ^{0} n$ at $P_{L ab} =$ 8 GeV/ $c$ .
↳ hep-phnucl-thPRC(2019)·2 citations
03
Implementation of a Radiation Protection System at Four Hospitals in Ethiopia
Gebre Mesay Geletu · Fikru Abiko · Shamble Sahlu
Diagnostic imaging procedure using ionizing radiation has been growing due to its enormous benefits. However, using ionizing radiation is also associated with harmful biological effects. Therefore it is important to take consideration on harmful effects of ionizing radiation and have adequate awareness on the area, in order to protect people without limiting the benefits. In Ethiopia, the status of radiation protection practices have not been studied previously, which remain nearly unknown especially around the study area. Thus, in filing this gap the present study initiated to assess status of implementation of radiation protection system. General observation, questionnaire and dose rate measurements were used to get all necessary data for the study. The dose rate measurements at control room (CR), waiting room (WR) and inside X-ray room (XR) were carried out using well calibrated Thermo FH 40 G-L10 survey meter. The results of the general observation and the questionnaire showed poor practice of radiation protection system. The dose rate recordings from CR and WR, when the X-ray machine being switched on or off are within permissible allowed value at all hospitals. XR machine off measurements at two locations are also within the range allowed value. However, XR machine on recordings shows a high level of radiation. This causes very high level unnecessary exposure situation for helper as a result of poor practices of radiation protection system which intern extremely increases the population dose. Therefore there is a great need of radiation protection agency activity at all Hospitals. Considering this scenario we suggest continuous training programs for radiographers; all Hospitals must full fill more modern radiation protection monitoring equipment and should have radiation protection advisers to monitor the radiation protection practices.
↳ physics.med-phnucl-thphysics.bio-phJournal of Radiology & Radiation therapy …·0 citations
04
Neutron star cooling and GW170817 constraint within quark-meson coupling models
Odilon Lourenço🇧🇷 · César H. Lenzi🇧🇷 · Mariana Dutra🇧🇷 · Tobias Frederico🇧🇷 · Mrutunjaya Bhuyan🇲🇾 · Rodrigo Negreiros🇧🇷 · Cesar V. Flores🇧🇷 · Guilherme Grams🇧🇷 · Débora P. Menezes🇧🇷
In the present work we used five different versions of the quark-meson coupling (QMC) model to compute astrophysical quantities related to the GW170817 event and to neutron star cooling process. Two of the models are based on the original bag potential structure and three versions consider a harmonic oscillator potential to confine the quarks. The bag-like models also incorporate the pasta phase used to describe the inner crust of neutron stars. We show that the pasta phase always play a minor or negligible role in all studies. Moreover, while no clear correlation between the models that satisfy the GW170817 constraints and the slope of the symmetry energy is found, a clear correlation is observed between the slope and the fact that the cooling is fast or slow, i.e., fast (slow) cooling is related to higher (lower) values of the slope. We did not find one unique model that can describe, at the same time, GW170817 constraints and give a perfect description of the possible cooling processes.
↳ astro-ph.HEnucl-thCPC(2021)·10 citations

Affiliations

first authorsco-authorsvia INSPIRE

Transport coefficients for multi-component gas of hadrons using Chapman Enskog method

A new combined analysis of elastic and charge exchange KN(KˉN) scatterings in the Regge realm

Implementation of a Radiation Protection System at Four Hospitals in Ethiopia

Neutron star cooling and GW170817 constraint within quark-meson coupling models

Affiliations

A new combined analysis of elastic and charge exchange $K N (K ˉ N)$ scatterings in the Regge realm