Nuclear Theory·nucl-th

Wednesday·June 22, 2016

12 papers—5 primary·7 cross-listed

06
Decoherence in Sub-Systems of an Isolated System and the Disappearance of Quantum Multiverse
Takuji Ishikawa
This study was started to know mysterious classicality of nuclei. Using three particles model without external environments, it is found that decisions of respective state of three particles by decoherence are not simultaneous. Furthermore, in this model, wave function of total three body system collapses spontaneously without any external environments. Therefore we may able to insist that a wavefunction of our universe has already collapsed spontaneously without any external observer, because of the same mechanism with this model.
↳ quant-phnucl-th0 citations
07
High Resolution Nonperturbative Light-Front Simulations of the True Muonium Atom
Henry Lamm🇺🇸 · Richard Lebed🇺🇸
Through the development of a parallel code called TMSWIFT, an extensive light-front quantization study of the nonperturbative spectrum of the bound state $(μ^{+} μ^{-})$ , true muonium, has been performed. Using Padé approximants, it has been possible to extract continuum and infinite-cutoff limits for the singlet and triplet states for a range of values of the coupling constant $α$ . This data set allows for an investigation of the $α$ dependence of the light-front spectra, the results of which are compared to standard calculations. Decay constants have also been obtained. Improved calculations have been undertaken for the energy shifts due to the presence of a second, lighter flavor ( $e$ ). Finally, initial results for three-flavor ( $e$ , $μ$ , $τ$ ) calculations are presented.
↳ hep-phnucl-thphysics.comp-phPRD(2016)·7 citations
08
Correlations of conserved number mixed susceptibilities in a hadron resonance gas model
D. K. Mishra🇮🇳 · P. K. Netrakanti🇮🇳 · Bedangadas Mohanty🇮🇳
The ratios of off-diagonal and diagonal susceptibilities of conserved charges are studied using a hadron resonance gas (HRG) model with an emphasis towards providing a proper baseline for comparison to the corresponding future experimental measurements. We have studied the effect of kinematic acceptances, transverse momentum ( $p_{T}$ ) and pseudorapidity ( $η$ ), and different charged states on the ratios of the calculated susceptibilities. We find that the effect of $p_{T}$ and $η$ acceptance on the ratio of the susceptibilities are small relative to their dependence on the beam energy or the charged states of the used particles. We also present a HRG based calculation for various combinations of cumulant ratios of protons and pions, recently proposed as robust observables (with no theoretical uncertainties) for critical point search in the experiments. These results which increase as a function of collision energy will provide a better baseline for non-critical point physics compared to Poisson expectation.
↳ hep-phnucl-exnucl-thPRC(2016)·6 citations
09
Flavor-dependent eigenvolume interactions in a hadron resonance gas
P. Alba🇩🇪 · V. Vovchenko🇩🇪 · M. I. Gorenstein🇺🇦 · H. Stoecker🇩🇪
Eigenvolume effects in the hadron resonance gas (HRG) model are studied for experimental hadronic yields in nucleus-nucleus collisions. If particle eigenvolumes are different for different hadron species, the excluded volume HRG (EV-HRG) improves fits to multiplicity data. In particular, using different mass~-~volume relations for strange and non-strange hadrons we observe a remarkable improvement in the quality of the fits. This effect appears to be rather insensitive to other details in the schemes employed in the EV-HRG. We show that the parameters found from fitting the data of the ALICE Collaboration in central Pb+Pb collisions at the collision energy $s_{NN} = 2.76$ ~TeV entail the same improvement for all centralities at the same collision energy, and for the RHIC and SPS data at lower collision energies. Our findings are put in the context of recent fits of lattice QCD results.
↳ hep-phnucl-thNPA(2018)·57 citations
10
A local and renormalizable framework for the gauge-invariant operator $A_{m i n}^{2}$ in Euclidean Yang-Mills theories in linear covariant gauges
M. A. L. Capri🇧🇷 · D. Fiorentini🇧🇷 · M. S. Guimaraes🇧🇷 · B. W. Mintz🇧🇷 · L. F. Palhares🇧🇷 · S. P. Sorella🇧🇷
We address the issue of the renormalizability of the gauge-invariant non-local dimension-two operator $A_{min}^{2}$ , whose minimization is defined along the gauge orbit. Despite its non-local character, we show that the operator $A_{min}^{2}$ can be cast in local form through the introduction of an auxiliary Stueckelberg field. The localization procedure gives rise to an unconventional kind of Stueckelberg-type action which turns out to be renormalizable to all orders of perturbation theory. In particular, as a consequence of its gauge invariance, the anomalous dimension of the operator $A_{min}^{2}$ turns out to be independent from the gauge parameter $α$ entering the gauge-fixing condition, being thus given by the anomalous dimension of the operator $A^{2}$ in the Landau gauge.
↳ hep-thhep-lathep-phnucl-thPRD(2016)·40 citations
11
$P$ -wave coupled-channel scattering of $B_{s} π, B_{s}^{*} π, B K, B^{*} K$ and the puzzling $X (5568)$
Xian-Wei Kang🇪🇸 · J. A. Oller🇪🇸
The D0 Collaboration has recently reported a narrow peak structure in the $B_{s}^{0} π^{\pm}$ invariant-mass spectrum, that is called $X (5568)$ . Its proposed quantum numbers $J^{P} = 0^{+} / 1^{+}$ are not determined unambiguously, and we show that one can fit the data assuming $J^{P} = 1^{-}$ with the same mass and width for the resonance signal. The corresponding isovector $P$ -wave coupled-channel scattering involving the states $B_{s} π$ , $B_{s}^{*} π$ , $B K$ and $B^{*} K$ is studied employing leading-order Heavy Meson Chiral Perturbation Theory, which is then unitarized making use of standard techniques from Unitary Chiral Perturbation Theory. The subtraction constants that appear in the unitarization process are determined by a $u$ -channel crossing symmetry constraint or by naturalness arguments, being the numerical values obtained in both cases quite closed, and no further freedom is left in the model. A crucial point is that if the $X (5568)$ is $1^{-}$ and decaying into $B_{s}^{0} π^{\pm}$ then it should appear as a pole in the $T$ -matrix elements. It finally turns out that no $X (5568)$ pole is found that can be qualified as dynamically generated from the isovector $P$ -wave coupled-channel dynamics. This result disfavors the interpretation of the $X (5568)$ within a "molecular" picture.
↳ hep-phhep-exnucl-thPRD(2016)·44 citations
12
Big Bang Nucleosynthesis in the presence of sterile neutrinos with altered dispersion relations
Elke Aeikens🇦🇹 · Heinrich Päs🇩🇪 · Sandip Pakvasa🇺🇸 · Thomas J. Weiler🇺🇸
Big Bang Nucleosynthesis imposes stringent bounds on light sterile neutrinos mixing with the active flavors. Here we discuss how altered dispersion relations can weaken such bounds and allow compatibility of new sterile neutrino degrees of freedom with a successful generation of the light elements in the early Universe.
↳ hep-phastro-ph.COnucl-thPRD(2016)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE

Decoherence in Sub-Systems of an Isolated System and the Disappearance of Quantum Multiverse

High Resolution Nonperturbative Light-Front Simulations of the True Muonium Atom

Correlations of conserved number mixed susceptibilities in a hadron resonance gas model

Flavor-dependent eigenvolume interactions in a hadron resonance gas

A local and renormalizable framework for the gauge-invariant operator Amin2​ in Euclidean Yang-Mills theories in linear covariant gauges

P-wave coupled-channel scattering of Bs​π,Bs∗​π,BK,B∗K and the puzzling X(5568)

Big Bang Nucleosynthesis in the presence of sterile neutrinos with altered dispersion relations

Affiliations

A local and renormalizable framework for the gauge-invariant operator $A_{m i n}^{2}$ in Euclidean Yang-Mills theories in linear covariant gauges

$P$ -wave coupled-channel scattering of $B_{s} π, B_{s}^{} π, B K, B^{} K$ and the puzzling $X (5568)$