In-medium Yang-Mills equations: a derivation and canonical quantization

The equations for Yang-Mills field in a medium are derived in a linear approximation with respect to the gauge coupling parameter and the external field. The obtained equations closely resemble the macroscopic Maxwell equations. A canonical quantization is performed for a family of Fermi-like gauges in the case of constant and diagonal (in the group indices) tensors of electric permittivity and magnetic permeability. The physical subspace is defined and the gauge field propagator is evaluated for a particular choice of the gauge. The propagator is applied for evaluation of the cross-section of ellastic quark scattering in the Born approximation. Possible applications to Cherenkov-type gluon radiation are commented briefly.Comment: 27 pages, references added, version extended with emphasis on non-Abelian gauge group impact on medium characteristics. To appear in J. Phys.

High-Precision Measurement of the 19Ne Half-Life and Implications for Right-Handed Weak Currents

We report a precise determination of the 19Ne half-life to be $T_{1/2} = 17.262 \pm 0.007$ s. This result disagrees with the most recent precision measurements and is important for placing bounds on predicted right-handed interactions that are absent in the current Standard Model. We are able to identify and disentangle two competing systematic effects that influence the accuracy of such measurements. Our findings prompt a reassessment of results from previous high-precision lifetime measurements that used similar equipment and methods.Comment: 5 pages and 5 figures. Paper accepted for publication in Phys. Rev. Let

High-spin States in \u3csup\u3e191, 193\u3c/sup\u3eAu and \u3csup\u3e192\u3c/sup\u3ePt: Evidence for Oblate Deformation and Triaxial Shapes

High-spin states of 191, 193Au and 192Pt have been populated in the 186W(11B, xn) and 186W(11B, p4n) reactions, respectively, at a beam energy of 68 MeV and their γ decay was studied using the YRAST Ball detector array at the Wright Nuclear Structure Laboratory at Yale University. The level scheme of 193Au has been extended up to Iπ = 55/2+. New transitions were observed also in 191Au and 192Pt. Particle-plus-Triaxial-Rotor (PTR) and Total Routhian Surface (TRS) calculations were performed to determine the equilibrium deformations of the Au isotopes. The predictions for oblate deformations in these nuclei are in agreement with the experimental data. Development of nonaxial shapes is discussed within the framework of the PTR model

Inelastic scattering of 9Li and excitation mechanism of its first excited state

The first measurement of inelastic scattering of 9Li from deuterons at the ISAC facility is reported. The measured angular distribution for the first excited state confirms the nature of excitation to be an E2 transition. The quadrupole deformation parameter is extracted from an analysis of the angular distribution.Web of Scienc

Structure of high-spin states in 91Sr and 92Sr

The nuclei 91Sr and 92Sr were produced at high spin as fission fragments following the fusion reaction 36S+ 159Tb at 165 MeV. γ rays were detected with the Gammasphere array. The level schemes of 91Sr and 92Sr were extended up to E≈6 MeV and E≈8 MeV, respectively. Level structures in 91Sr and 92Sr were interpreted in shell-model calculations performed in the configuration space (0f5/2, 1p3/2, 1p1/2, 0g9/2) for the protons and (1p1/2, 0g9/2, 1d5/2) for the neutrons. Negative-parity states in the yrast sequences are described in these calculations by coupling 3- proton excitations to the unpaired 1d5/2 neutrons. A possible reduction of the gap between the proton 1p3/2 and 1p1/2 orbitals in 92Sr is discussed

Triaxial Deformation and Nuclear Shape Transition in \u3csup\u3e192\u3c/sup\u3eAu

Background: Nuclei in the A≈190 mass region show gradual shape changes from prolate through nonaxial deformed shapes and ultimately towards spherical shapes as the Pb region is approached. Exploring how this shape evolution occurs will help us understand the evolution of collectivity in this region. Purpose: The level scheme of the 192Au nucleus in A ≈ 190 region was studied in order to deduce its deformations. Methods: High-spin states of 192Au have been populated in the 186W(11B, 5n) reaction at a beam energy of 68 MeV and their γ decay was studied using the YRAST Ball detector array at the Wright Nuclear Structure Laboratory (WNSL), Yale University. Results: Based on double and triple γ-ray coincidence data the level scheme of 192Au has been extended up to Iπ = 32+ at an excitation energy of ∼6 MeV. Conclusion: The results are discussed in the framework of pairing and deformation self-consistent total Routhian surface (TRS) and cranked shell model (CSM) calculations. The comparison of the experimental observations with the calculations indicates that this nucleus takes a nonaxial shape similar to other Au nuclei in this region

Restoring the valence-shell stabilization in Nd-140

A projectile Coulomb-excitation experiment was performed at the radioactive-ion beam facility HIE-ISOLDE at CERN to obtain E2 and M1 transition matrix elements of Nd-140 using the multistep Coulomb-excitation code GOSIA. The absolute M1 strengths, B(M1; 2(2)(-) -> 2(1)(+)) = 0.033(8)mu(2)(N), B(M1 ; 2(3)(+) -> 2(1)(+)) = 0.26(-0.10)(+0.11)mu(2)(N), and B(M1; 2(4)+ -> 2(1)(+)) <0.04 mu(2)(N) identify the 2(3)(+) state as the main fragment of the one-quadrupole-phonon proton-neutron mixed-symmetry state of Nd-140. The degree of F-spin mixing in Nd-140 was quantified with the determination of the mixing matrix element VF-mix <7(-7)(-13) keV.Peer reviewe

In-medium QCD and Cherenkov gluons

The equations of in-medium gluodynamics are proposed. Their classical lowest order solution is explicitly shown for a color charge moving with constant speed. For nuclear permittivity larger than 1 it describes emission of Cherenkov gluons resembling results of classical electrodynamics. The choice of nuclear permittivity and Lorentz-invariance of the problem are discussed. Effects induced by the transversely and longitudinally moving (relative to the collision axis) partons at LHC energies are described.Comment: 13 p., misprints correcte