scholarly journals Model independent expansion history from supernovae: Cosmology versus systematics

2019 ◽  
Vol 485 (2) ◽  
pp. 2783-2790 ◽  
Author(s):  
Benjamin L’Huillier ◽  
Arman Shafieloo ◽  
Eric V Linder ◽  
Alex G Kim
Keyword(s):  
Gaussian Process Regression ◽  
Om Diagnostic ◽  
Independent Analysis ◽  
Data Compilation ◽  
Good Consistency ◽  
Linear Correction ◽  
Distance Data ◽  
Model Independent ◽  
Cosmic History ◽  
Independent Expansion

Abstract We examine the Pantheon supernovae distance data compilation in a model independent analysis to test the validity of cosmic history reconstructions beyond the concordance ΛCDM cosmology. Strong deviations are allowed by the data at z ≳ 1 in the reconstructed Hubble parameter, Om diagnostic, and dark energy equation of state. We explore three interpretations: 1) possibility of the true cosmology being far from ΛCDM, 2) supernovae property evolution, and 3) survey selection effects. The strong (and theoretically problematic) deviations at z ≳ 1 vanish and good consistency with ΛCDM is found with a simple Malmquist-like linear correction. The adjusted data is robust against the model independent iterative smoothing reconstruction. However, we caution that while by eye the original deviation from ΛCDM is striking, χ2 tests do not show the extra linear correction parameter is statistically significant, and a model-independent Gaussian Process regression does not find significant evidence for the need for correction at high-redshifts.

scholarly journals Testing lepton flavour universality with (semi)-leptonic $$\varvec{D_{(s)}}$$ decays

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Robert Fleischer ◽  
Ruben Jaarsma ◽  
Gabriël Koole
Keyword(s):  
Standard Model ◽  
Branching Ratios ◽  
Current Data ◽  
Leptonic Decays ◽  
Independent Analysis ◽  
The Standard Model ◽  
Model Independent ◽  
Pseudo Scalar ◽  
The Impact ◽  
Lepton Flavour

Abstract Data in B-meson decays indicate violations of lepton flavour universality, thereby raising the question about such phenomena in the charm sector. We perform a model-independent analysis of NP contributions in (semi)-leptonic decays of $$D_{(s)}$$D(s) mesons which originate from $$c \rightarrow d \bar{{\ell }} \nu _l$$c→dℓ¯νl and $$c \rightarrow s \bar{{\ell }} \nu _{\ell }$$c→sℓ¯νℓ charged-current interactions. Starting from the most general low-energy effective Hamiltonian containing four-fermion operators and the corresponding short-distance coefficients, we explore the impact of new (pseudo)-scalar, vector and tensor operators and constrain their effects through the interplay with current data. We pay special attention to the elements $$|V_{cd}|$$|Vcd| and $$|V_{cs}|$$|Vcs| of the Cabibbo–Kobayashi–Maskawa matrix and extract them from the $$D_{(s)}$$D(s) decays in the presence of possible NP decay contributions, comparing them with determinations utilizing unitarity. We find a picture in agreement with the Standard Model within the current uncertainties. Using the results from our analysis, we make also predictions for leptonic $$D_{(s)}^+ \rightarrow e^+ \nu _e$$D(s)+→e+νe modes which could be hugely enhanced with respect to their tiny Standard Model branching ratios. It will be interesting to apply our strategy at the future high-precision frontier.

scholarly journals Determining Higgs couplings with a model-independent analysis of h → γγ

2012 ◽  
Vol 2012 (6) ◽  
Author(s):  
Aleksandr Azatov ◽  
Roberto Contino ◽  
Daniele Del Re ◽  
Jamison Galloway ◽  
Marco Grassi ◽  
...  
Keyword(s):  
Independent Analysis ◽  
Model Independent

Model-independent analysis of the reaction π+p → π+π−Δ++

1977 ◽  
Vol 130 (2) ◽  
pp. 309-327 ◽  
Author(s):  
J.T. Donohue ◽  
M. Hontebeyrie ◽  
Y. Leroyer ◽  
C. Meyers
Keyword(s):  
Independent Analysis ◽  
Model Independent

scholarly journals Constraints on new physics in MFV models: A model-independent analysis of ΔF=1 processes

2009 ◽  
Vol 808 (1-2) ◽  
pp. 326-346 ◽  
Author(s):  
Tobias Hurth ◽  
Gino Isidori ◽  
Jernej F. Kamenik ◽  
Federico Mescia
Keyword(s):  
New Physics ◽  
Independent Analysis ◽  
Model Independent

scholarly journals Cosmological parameter analyses using transversal BAO data

2020 ◽  
Vol 497 (2) ◽  
pp. 2133-2141 ◽  
Author(s):  
Rafael C Nunes ◽  
Santosh K Yadav ◽  
J F Jesus ◽  
Armando Bernui
Keyword(s):  
Cold Dark Matter ◽  
Cosmological Parameters ◽  
Mass Scale ◽  
Joint Analysis ◽  
Observational Constraints ◽  
Independent Analysis ◽  
Local Measurements ◽  
Model Independent ◽  
Free Parameters ◽  
Dynamical Dark Energy

ABSTRACT We investigate observational constraints on cosmological parameters combining 15 measurements of the transversal BAO scale (obtained free of any fiducial cosmology) with Planck–CMB data to explore the parametric space of some cosmological models. We investigate how much Planck + transversal BAO data can constraint the minimum Lambda cold dark matter (ΛCDM) model, and extensions, including neutrinos mass scale Mν, and the possibility for a dynamical dark energy (DE) scenario. Assuming the ΛCDM cosmology, we find H0 = 69.23 ± 0.50 km s−1 Mpc−1, Mν < 0.11 eV, and rdrag = 147.59 ± 0.26 Mpc (the sound horizon at drag epoch) from Planck + transversal BAO data. When assuming a dynamical DE cosmology, we find that the inclusion of the BAO data can indeed break the degeneracy of the DE free parameters, improving the constraints on the full parameter space significantly. We note that the model is compatible with local measurements of H0 and there is no tension on H0 estimates in this dynamical DE context. Also, we discuss constraints and consequences from a joint analysis with the local H0 measurement from SH0ES. Finally, we perform a model-independent analysis for the deceleration parameter, q(z), using only information from transversal BAO data.

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