Charmonium excited state spectrum in lattice QCD

Working with a large basis of covariant derivative-based meson interpolating fields we demonstrate the feasibility of reliably extracting multiple excited states using a variational method. The study is performed on quenched anisotropic lattices with clover quarks at the charm mass. We demonstrate how a knowledge of the continuum limit of a lattice interpolating field can give additional spin-assignment information, even at a single lattice spacing, via the overlap factors of interpolating field and state. Excited state masses are systematically high with respect to quark potential model predictions and, where they exist, experimental states. We conclude that this is most likely a result of the quenched approximation.Comment: Fixed typos: normalisation of chi-squared, some operator projections in appendix, missing lattice irrep tabl

Constraining dark matter decays with cosmic microwave background and weak lensing shear observations

From observations at low and high redshifts, it is well known that the bulk of dark matter (DM) has to be stable or at least very long-lived. However, the possibility that a small fraction of DM is unstable or that all DM decays with a half-life time ($\tau$) significantly longer than the age of the Universe is not ruled out. One-body decaying dark matter (DDM) consists of a minimal extension to the $\Lambda$CDM model. It causes a modification of the cosmic growth history as well as a suppression of the small-scale clustering signal, providing interesting consequences regarding the $S_8$ tension, which is the observed difference in the clustering amplitude between weak-lensing (WL) and cosmic microwave background (CMB) observations. In this paper, we investigate models in which a fraction or all DM decays into radiation, focusing on the long-lived regime, that is, $\tau \gtrsim H_0^{-1}$ ( $H_0^{-1}$ being the Hubble time). We used WL data from the Kilo-Degree Survey (KiDS) and CMB data from Planck. First, we confirm that this DDM model cannot alleviate the $S_8$ difference. We then show that the most constraining power for DM decay does not come from the nonlinear WL data, but from CMB via the integrated Sachs-Wolfe effect. From the CMB data alone, we obtain constraints of $\tau \geq 288$~Gyr if all DM is assumed to be unstable, and we show that a maximum fraction of $f=0.07$ is allowed to decay assuming the half-life time to be comparable to (or shorter than) one Hubble time. The constraints from the KiDS-1000 WL data are significantly weaker, $\tau \geq 60$~Gyr and $f<0.34$. Combining the CMB and WL data does not yield tighter constraints than the CMB alone, except for short half-life times, for which the maximum allowed fraction becomes $f=0.03$. All limits are provided at the 95% confidence level

Methodology of transport regulation in the Slovak Republic

This article deals with the analysis of the present state of transport regulation, the relevant legislation, the reasons behind regulations, its rules and tools, the charges to be paid for the usage of the railway infrastructure in the Slovak Republic as a subject of the regulations and problems of financing the investments in the railway infrastructure

Probing the two-body decaying dark matter scenario with weak lensing and the cosmic microwave background

Decaying dark matter (DDM) scenarios have recently re-gained attention due to their potential ability to resolve the well-known clustering (or $S_8$) tension between weak lensing (WL) and cosmic microwave background (CMB) measurements. In this paper, we investigate a well-established model, where the original dark matter (DM) particle decays into a massless and a massive daughter particles. The latter obtains a velocity kick during the decay process resulting in a suppression of the matter power spectrum at scales that are observable with WL shear observations. We perform the first fully nonlinear WL analysis of this two-body decaying dark matter ($\Lambda$DDM) scenario including intrinsic alignment and baryonic feedback processes. We thereby use the cosmic shear band power spectra from the KiDS-1000 data combining it with temperature and polarization data from Planck to constrain the $\Lambda$DDM model. We report new limits on the decay rate and mass splitting parameters that are significantly stronger than previous results, especially for the case of low mass splittings. We also investigate the $S_8$ tension only finding a marginal improvement of 0.3$\sigma$ for $\Lambda$DDM compared to the $\Lambda$CDM case. The improvement is not caused by a shift but a slight bloating of the posterior contours caused by the additional free model parameters. We therefore conclude that the two-body $\Lambda$DDM model does not provide a convincing solution to the $S_8$ tension. Our emulator to model the nonlinear $\Lambda$DDM power spectrum is published as part of the publicly available code DMemu at https://github.com/jbucko/DMemu.Comment: 16 pages, 13 figure