Nuclear Theory·nucl-th

Thursday·December 8, 2016

11 papers—5 primary·6 cross-listed

06
Universal description of radially excited heavy and light vector mesons
S. S. Afonin🇷🇺 · I. V. Pusenkov🇷🇺
A new qualitative stringlike picture for mesons is proposed which leads to a simple and intuitively clear generalization of linear radial Regge trajectories to the case of massive quarks. The obtained universal relation is successfully tested in the sector of unflavored vector mesons, where many radial excitations are known. Some new predictions are given. Our results suggest that the quark masses can be easily estimated from the spectra of radially excited mesons.
↳ hep-phnucl-thPRD(2014)·80 citations
07
On the nature of some SGRs and AXPs as rotation-powered neutron stars
Jaziel G. Coelho · D. L. Cáceres · R. C. R. de Lima · M. Malheiro · J. A. Rueda · R. Ruffini
We investigate the possibility that some SGRs/AXPs could be canonical rotation-powered pulsars using realistic NS structure parameters instead of fiducial values. We show that realistic NS parameters lowers the estimated value of the magnetic field and radiation efficiency, $L_{X} / E ˙_{rot}$ , with respect to estimates based on fiducial NS parameters. We show that nine SGRs/AXPs can be described as canonical pulsars driven by the NS rotational energy, for $L_{X}$ computed in the soft (2--10~keV) X-ray band. We compute the range of NS masses for which $L_{X} / E ˙_{rot} < 1$ . We discuss the observed hard X-ray emission in three sources of the group of nine potentially rotation-powered NSs. This additional hard X-ray component dominates over the soft one leading to $L_{X} / E ˙_{rot} > 1$ in two of them. We show that 9 SGRs/AXPs can be rotation-powered NSs if we analyze their X-ray luminosity in the soft 2--10~keV band. Interestingly, four of them show radio emission and six have been associated with supernova remnants (including Swift J1834.9-0846 the first SGR observed with a surrounding wind nebula). These observations give additional support to our results of a natural explanation of these sources in terms of ordinary pulsars. Including the hard X-ray emission observed in three sources of the group of potential rotation-powered NSs, this number of sources with $L_{X} / E ˙_{rot} < 1$ becomes seven. It remains open to verification 1) the accuracy of the estimated distances and 2) the possible contribution of the associated supernova remnants to the hard X-ray emission.
↳ astro-ph.HEastro-ph.SRhep-phnucl-thAstron.Astrophys.(2017)·17 citations
08
Reggeized model for $γ p \to ρ^{-} Δ^{++} (1232)$ photoproduction
Byung-Geel Yu🇰🇷 · Kook-Jin Kong🇰🇷
A model for the reaction $γ p \to ρ^{-} Δ^{++}$ is presented with the $t$ -channel $π + ρ$ exchanges reggeized to describe the reaction up to high energies. Gauge invariance of $ρ$ exchange is discussed in connection with the convergence of the reaction cross section at high energy. The roles of electromagnetic (EM) multipole moments of $Δ^{++}$ baryon and of $ρ^{-}$ meson are analyzed in total and differential cross sections and spin density matrix elements. Photon polarization asymmetry $Σ$ is predicted for a measurement of electromagnetic moments of $ρ^{-}$ and of $Δ^{++}$ .
↳ hep-phnucl-thJ.Phys.G(2020)·3 citations
09
Radiative corrections to elastic proton-electron scattering measured in coincidence
G.I. Gakh🇺🇦 · M.I. Konchatnij🇺🇦 · N.P. Merenkov🇺🇦 · Egle Tomasi-Gustafsson🇫🇷
The differential cross section for elastic scattering of protons on electrons at rest is calculated taking into account the QED radiative corrections to the leptonic part of interaction. These model-independent radiative corrections arise due to emission of the virtual and real soft and hard photons as well as to vacuum polarization. We analyze an experimental setup when both the final particles are recorded in coincidence and their energies are determined within some uncertainties. The kinematics, the cross section, and the radiative corrections are calculated and numerical results are presented.
↳ hep-phnucl-thPRC(2017)·5 citations
10
The effect of magnetization and electric polarization on the anomalous transport coefficients of a chiral fluid
N. Sadooghi🇮🇷 · S.M.A. Tabatabaee🇮🇷
The effects of finite magnetization and electric polarization on dissipative and non-dissipative (anomalous) transport coefficients of a chiral fluid are studied. First, using the second law of thermodynamics as well as Onsager's time reversal symmetry principle, the complete set of dissipative transport coefficients of this medium is derived. It is shown that the properties of the resulting shear and bulk viscosities are mainly affected by the anisotropy induced by external electric and magnetic fields. Then, using the fact that the anomaly induced currents do not contribute to entropy production, the corresponding algebro-differential equations to non-dissipative anomalous transport coefficients are derived in a certain derivative expansion. The solutions of these equations show that, within this approximation, anomalous transport coefficients are, in particular, given in terms of the electric susceptibility of the medium.
↳ hep-thhep-phnucl-thNew J.Phys.(2017)·7 citations
11
Neutrino-induced one-pion production revisited: the $ν_{μ} n \to μ^{-} n π^{+}$ channel
E. Hernández🇪🇸 · J. Nieves🇪🇸
Understanding single pion production reactions on free nucleons is the first step towards a correct description of these processes in nuclei, which are important for signal and background contributions in current and near future accelerator neutrino oscillation experiments. In this work, we reanalyze our previous studies of neutrino-induced one-pion production on nucleons for outgoing $π N$ invariant masses below 1.4 GeV. Our motivation is to get a better description of the $ν_{μ} n \to μ^{-} n π^{+}$ cross section, for which current theoretical models give values significantly below data. This channel is very sensitive to the crossed $Δ (1232)$ contribution and thus to spin 1/2 components in the Rarita-Schwinger $Δ$ propagator. We show how these spin 1/2 components are nonpropagating and give rise to contact interactions. In this context, we point out that the discrepancy with experiment might be corrected by the addition of appropriate extra contact terms and argue that this procedure will provide a natural solution to the $ν_{μ} n \to μ^{-} n π^{+}$ puzzle. To keep our model simple, in this work we propose to change the strength of the spin 1/2 components in the $Δ$ propagator and use the $ν_{μ} n \to μ^{-} n π^{+}$ data to constraint its value. With this modification, we now find a good reproduction of the $ν_{μ} n \to μ^{-} n π^{+}$ cross section without affecting the good results previously obtained for the other channels. We also explore how this change in the $Δ$ propagator affects our predictions for pion photoproduction and find also a better agreement with experiment than with the previous model.
↳ hep-phnucl-thPRD(2017)·39 citations

Affiliations

first authorsco-authorsvia INSPIRE

Universal description of radially excited heavy and light vector mesons

On the nature of some SGRs and AXPs as rotation-powered neutron stars

Reggeized model for γp→ρ−Δ++(1232) photoproduction

Radiative corrections to elastic proton-electron scattering measured in coincidence

The effect of magnetization and electric polarization on the anomalous transport coefficients of a chiral fluid

Neutrino-induced one-pion production revisited: the νμ​n→μ−nπ+ channel

Affiliations

Reggeized model for $γ p \to ρ^{-} Δ^{++} (1232)$ photoproduction

Neutrino-induced one-pion production revisited: the $ν_{μ} n \to μ^{-} n π^{+}$ channel