Uniform and weak stability of Bresse system with one infinite memory in the shear angle displacements

In this paper, we consider a one-dimensional linear Bresse system in a bounded open interval with one infinite memory acting only on the shear angle equation. First, we establish the well posedness using the semigroup theory. Then, we prove two general (uniform and weak) decay estimates depending on the speeds of wave propagations and the arbitrary growth at infinity of the relaxation function.

Derivation of the set of the fundamental interactions from first principles

Global conservation laws require the fundamental interactions to be processes which transfer information from one particle to another. Therefore, in order to show what types of interactions may exist, we derive from the very first principles a set of the most fundamental information transfers and their basic properties. Within these information transfers, we identify candidates for gravitational, electromagnetic and strong scattering, and also for weak decay. We do it by taking the characteristic properties of each fundamental interaction, such as confinement or parity violation, and by using them to rule out information transfers without these properties. The found mapping then makes possible to study the information transfers in order to get knowledge about the corresponding fundamental interactions.

Hyperons in Finite and Infinite Nuclear Systems

In this work, we shortly review the role and properties of hyperons in finite and infinite nuclear systems such as hypernuclei and neutron stars. Particularly, we describe different production mechanisms of hypernuclei, discuss some aspects of their γ-ray spectroscopy and their weak decay modes, and give a few strokes on their theoretical description. We reexamine also the role played by hyperons on the properties of neutron and proto-neutron stars with a special emphasis on the well-known “hyperon puzzle”, of which we discuss some of the solutions that have been proposed to tackle this problem. Finally, we review the role of hyperons on the cooling properties of newly born neutron stars and on the so-called r-mode instability.

Asymptotic Stability of Minkowski Space-Time with Non-compactly Supported Massless Vlasov Matter

We prove the global asymptotic stability of the Minkowski space for the massless Einstein–Vlasov system in wave coordinates. In contrast with previous work on the subject, no compact support assumptions on the initial data of the Vlasov field in space or the momentum variables are required. In fact, the initial decay in v is optimal. The present proof is based on vector field and weighted vector field techniques for Vlasov fields, as developed in previous work of Fajman, Joudioux, and Smulevici, and heavily relies on several structural properties of the massless Vlasov equation, similar to the null and weak null conditions. To deal with the weak decay rate of the metric, we propagate well-chosen hierarchized weighted energy norms which reflect the strong decay properties satisfied by the particle density far from the light cone. A particular analytical difficulty arises at the top order, when we do not have access to improved pointwise decay estimates for certain metric components. This difficulty is resolved using a novel hierarchy in the massless Einstein–Vlasov system, which exploits the propagation of different growth rates for the energy norms of different metric components.

CBM Performance for Λ Hyperon Directed Flow Measurements in Au + Au Collisions at 12A GeV/c

We present the current status of the performance studies of Λ hyperon directed flow measurement with the CBM experiment at the future FAIR facility in Darmstadt. Kalman Filter mathematics is used to reconstruct Λ→pπ− weak decay kinematics, while the Particle Finder Simple package is used to optimize criteria for Λ hyperon candidate selection. Directed flow of Λ hyperons is studied as a function of rapidity, transverse momentum and collision centrality. The effects on flow measurement due to non-uniformity of the CBM detector response in the azimuthal angle, transverse momentum and rapidity are corrected using the QnTools analysis framework.

Hydrodynamic Approach to Electronic Transport in Graphene: Energy Relaxation

In nearly compensated graphene, disorder-assisted electron-phonon scattering or “supercollisions” are responsible for both quasiparticle recombination and energy relaxation. Within the hydrodynamic approach, these processes contribute weak decay terms to the continuity equations at local equilibrium, i.e., at the level of “ideal” hydrodynamics. Here we report the derivation of the decay term due to weak violation of energy conservation. Such terms have to be considered on equal footing with the well-known recombination terms due to nonconservation of the number of particles in each band. At high enough temperatures in the “hydrodynamic regime” supercollisions dominate both types of the decay terms (as compared to the leading-order electron-phonon interaction). We also discuss the contribution of supercollisions to the heat transfer equation (generalizing the continuity equation for the energy density in viscous hydrodynamics).

Decay amplitudes to three hadrons from finite-volume matrix elements

We derive relations between finite-volume matrix elements and infinite-volume decay amplitudes, for processes with three spinless, degenerate and either identical or non-identical particles in the final state. This generalizes the Lellouch-Lüscher relation for two-particle decays and provides a strategy for extracting three-hadron decay amplitudes using lattice QCD. Unlike for two particles, even in the simplest approximation, one must solve integral equations to obtain the physical decay amplitude, a consequence of the nontrivial finite-state interactions. We first derive the result in a simplified theory with three identical particles, and then present the generalizations needed to study phenomenologically relevant three-pion decays. The specific processes we discuss are the CP-violating K → 3π weak decay, the isospin-breaking η → 3π QCD transition, and the electromagnetic γ* → 3π amplitudes that enter the calculation of the hadronic vacuum polarization contribution to muonic g − 2.

Theoretical study of the $$D^0 \rightarrow K^- \pi ^+ \eta $$ reaction

We develop a model to study the $$D^0 \rightarrow K^- \pi ^+ \eta $$ D 0 → K - π + η weak decay, starting with the color favored external emission and Cabibbo favored mode at the quark level. A less favored internal emission decay mode is also studied as a source of small corrections. Some pairs of quarks are allowed to hadronize producing two pseudoscalar mesons, which posteriorly are allowed to interact to finally provide the $$K^- \pi ^+ \eta $$ K - π + η state. The chiral unitary approach is used to take into account the final state interaction of pairs of mesons, which has as a consequence the production of the $$\kappa $$ κ ($$K^*_0(700)$$ K 0 ∗ ( 700 ) ) and the $$a_0(980)$$ a 0 ( 980 ) resonances, well visible in the invariant mass distributions. We also introduce the $$\bar{K}^{*0} \eta $$ K ¯ ∗ 0 η production in a phenomenological way and show that the s-wave pseudoscalar interaction together with this vector excitation mode are sufficient to provide a fair reproduction of the experimental data. The model provides the relative weight of the $$a_0(980)$$ a 0 ( 980 ) to the $$\kappa $$ κ excitation, and their strength is clearly visible in the low energy part of the $$K \pi $$ K π spectrum.

Semileptonic decay of $$\varOmega _c^0 \rightarrow \varXi ^- l^+ \nu _l$$ from light-cone sum rules

The weak decay process of $$\varOmega _c$$ Ω c to $$\varXi $$ Ξ is calculated in the method of QCD light-cone sum rule. The decay width of $$\varOmega _c^0 \rightarrow \varXi ^- l^+ \nu _l$$ Ω c 0 → Ξ - l + ν l and its decay branching ratio are also calculated with the form factors from this work’s calculation. To the twist-6 distribution amplitudes, the form factors $$f_1=0.66\pm 0.02, f_2=-0.76\pm 0.03, g_1=0.06\pm 0.01$$ f 1 = 0.66 ± 0.02 , f 2 = - 0.76 ± 0.03 , g 1 = 0.06 ± 0.01 and $$g_2=-0.44\pm 0.01$$ g 2 = - 0.44 ± 0.01 are given at zero recoil point. The result of the semileptonic decay width of $$\varOmega _c^0 \rightarrow \varXi ^-l^+\nu _l$$ Ω c 0 → Ξ - l + ν l is $$\varGamma =(7.51\pm 0.36)\times 10^{-15}~\mathrm{{GeV}}$$ Γ = ( 7.51 ± 0.36 ) × 10 - 15 GeV , and the prediction of the decay branching ratio $$Br(\varOmega _c^0\rightarrow \varXi ^-l^+\nu _l)=(3.06\pm 0.15)\times 10^{-3}$$ B r ( Ω c 0 → Ξ - l + ν l ) = ( 3.06 ± 0.15 ) × 10 - 3 . These results fit well with other works, and the decay width and branching ratio are improved. This not too small branching ratio gives a good direction to explore this decay channel in the future experiments.