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Vagnozzi, S., Di Valentino, E., Gariazzo, S., Melchiorri, A., Mena, O., & Silk, J. (2021). The galaxy power spectrum take on spatial curvature and cosmic concordance. Phys. Dark Universe, 33, 100851–17pp.
Abstract: The concordance of the ACDM cosmological model in light of current observations has been the subject of an intense debate in recent months. The 2018 Planck Cosmic Microwave Background (CMB) temperature anisotropy power spectrum measurements appear at face value to favour a spatially closed Universe with curvature parameter Omega(K) < 0. This preference disappears if Baryon Acoustic Oscillation (BAO) measurements are combined with Planck data to break the geometrical degeneracy, although the reliability of this combination has been questioned due to the strong tension present between the two datasets when assuming a curved Universe. Here, we approach this issue from yet another point of view, using measurements of the full-shape (FS) galaxy power spectrum, P(k), from the Baryon Oscillation Spectroscopic Survey DR12 CMASS sample. By combining Planck data with FS measurements, we break the geometrical degeneracy and find Omega(K) = 0.0023 +/- 0.0028. This constrains the Universe to be spatially flat to sub-percent precision, in excellent agreement with results obtained using BAO measurements. However, as with BAO, the overall increase in the best-fit chi(2) suggests a similar level of tension between Planck and P(k) under the assumption of a curved Universe. While the debate on spatial curvature and the concordance between cosmological datasets remains open, our results provide new perspectives on the issue, highlighting the crucial role of FS measurements in the era of precision cosmology.
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Yang, W. Q., Di Valentino, E., Pan, S., & Mena, O. (2021). Emergent Dark Energy, neutrinos and cosmological tensions. Phys. Dark Universe, 31, 100762–9pp.
Abstract: The Phenomenologically Emergent Dark Energy model, a dark energy model with the same number of free parameters as the flat Lambda CDM, has been proposed as a working example of a minimal model which can avoid the current cosmological tensions. A straightforward question is whether or not the inclusion of massive neutrinos and extra relativistic species may spoil such an appealing phenomenological alternative. We present the bounds on M-nu and N-eff and comment on the long standing H-0 and sigma(8) tensions within this cosmological framework with a wealth of cosmological observations. Interestingly, we find, at 95% confidence level, and with the most complete set of cosmological observations, M-nu similar to 0.21(-0.14)(+0.15) eV and N-eff = 3.03 +/- 0.32 i.e. an indication for a non-zero neutrino mass with a significance above 2 sigma. The well known Hubble constant tension is considerably easened, with a significance always below the 2 sigma level. (C) 2020 Elsevier B.V. All rights reserved.
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Godbole, R. M., Maharathy, S. P., Mandal, S., Mitra, M., & Sinha, N. (2021). Interference effect in lepton number violating and conserving meson decays for a left-right symmetric model. Phys. Rev. D, 104(9), 095009–22pp.
Abstract: We study the effect of interference on the lepton number violating (LNV) and lepton number conserving (LNC) three-bodymeson decaysM(1)(+)-> l(i) (+) l(j)(+)pi(+/-) that arise in a TeV-scale left-right symmetric model (LRSM) with degenerate or nearly degenerate right-handed (RH) neutrinos. The LRSM contains three RH neutrinos and a RH gauge boson. The RH neutrinos with masses in the range of M-N similar to (MeV-few GeV) can give resonant enhancement in the semileptonic LNV and LNC meson decays. In the case where only one RH neutrino contributes to these decays, the predicted new physics branching ratios of semileptonic LNV and LNC meson decaysM(1)(+)-> l(i)(+) l(j)(+) pi(-) andM(+) 1 -> l(i)(+)l(j)(-) pi(+) are equal. We find that with at least two RH neutrinos contributing to the process, the LNV and LNC decay rates can differ. Depending on the neutrino mixing angles and CP-violating phases, the branching ratios of LNVand LNC decay channelsmediated by the heavy neutrinos can be either enhanced or suppressed, and the ratio of these two rates can differ from unity.
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Huang, F., Sanz, V., Shu, J., & Xue, X. (2021). LIGO as a probe of dark sectors. Phys. Rev. D, 104(10), 095001–9pp.
Abstract: We show how current LIGO data is able to probe interesting theories beyond the Standard Model, particularly dark sectors where a dark Higgs boson triggers symmetry breaking via a first-order phase transition. We use publicly available LIGO O2 data to illustrate how these sectors, even if disconnected from the Standard Model, can be probed by gravitational wave detectors. We link the LIGO measurements with the model content and mass scale of the dark sector, finding that current O2 data are testing a broad set of scenarios that can be mapped into many different types of dark-sector models where the breaking of SU(N) theories with Nf fermions is triggered by a dark Higgs boson at scales ? similar or equal to 108-109 GeV with reasonable parameters for the scalar potential.
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Gao, F., Papavassiliou, J., & Pawlowski, J. M. (2021). Fully coupled functional equations for the quark sector of QCD. Phys. Rev. D, 103(9), 094013–25pp.
Abstract: We present a comprehensive study of the quark sector of 2 + 1 flavor QCD, based on a self-consistent treatment of the coupled system of Schwinger-Dyson equations for the quark propagator and the full quark-gluon vertex in the one-loop dressed approximation. The individual form factors of the quark-gluon vertex are expressed in a special tensor basis obtained from a set of gauge-invariant operators. The sole external ingredient used as input to our equations is the Landau gauge gluon propagator with 2 + 1 dynamical quark flavors, obtained from studies with Schwinger-Dyson equations, the functional renormalization group approach, and large volume lattice simulations. The appropriate renormalization procedure required in order to self-consistently accommodate external inputs stemming from other functional approaches or the lattice is discussed in detail, and the value of the gauge coupling is accurately determined at two vastly separated renormalization group scales. Our analysis establishes a clear hierarchy among the vertex form factors. We identify only three dominant ones, in agreement with previous results. The components of the quark propagator obtained from our approach are in excellent agreement with the results from Schwinger-Dyson equations, the functional renormalization group, and lattice QCD simulation, a simple benchmark observable being the chiral condensate in the chiral limit, which is computed as (245 MeV)(3). The present approach has a wide range of applications, including the self-consistent computation of bound-state properties and finite temperature and density physics, which are briefly discussed.
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