scholarly journals Model-independent constraints on modified gravity from current data and from the Euclid and SKA future surveys

2016 ◽  
Vol 2016 (12) ◽  
pp. 032-032 ◽  
Author(s):  
Laura Taddei ◽  
Matteo Martinelli ◽  
Luca Amendola
Keyword(s):  
Modified Gravity ◽  
Current Data ◽  
Model Independent

scholarly journals Cosmological gravity on all scales. Part II. Model independent modified gravity N-body simulations

2021 ◽  
Vol 2021 (06) ◽  
pp. 016
Author(s):  
Sankarshana Srinivasan ◽  
Daniel B. Thomas ◽  
Francesco Pace ◽  
Richard Battye
Keyword(s):  
Modified Gravity ◽  
Model Independent

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 Model-independent constraints on dark energy and modified gravity with the SKA

2015 ◽  
Author(s):  
Gongbo Zhao ◽  
D. J. Bacon ◽  
Roy Maartens ◽  
Mario Santos ◽  
Alvise Raccanelli
Keyword(s):  
Dark Energy ◽  
Modified Gravity ◽  
Model Independent

scholarly journals Astrophysical tests of screened modified gravity

2018 ◽  
Vol 27 (15) ◽  
pp. 1848008 ◽  
Author(s):  
Jeremy Sakstein
Keyword(s):  
Solar System ◽  
Modified Gravity ◽  
General Model ◽  
Thin Shell ◽  
Gravity Models ◽  
Specific Category ◽  
Model Independent ◽  
Relativistic Gravitation ◽  
Modified Gravity Models ◽  
Hubble Flow

Screened modified gravity models evade solar system tests of relativistic gravitation but exhibit novel and interesting effects on scales between the solar system and the Hubble flow: astrophysical scales. In this paper, we review how astrophysical tests using stars, galaxies, and clusters can be used to constrain these theories. We classify screening into three categories: thin-shell (chameleon, symmetron, and dilaton models), Vainshtein screening (e.g. Galileons and Horndeski), and Vainshtein breaking (e.g. beyond Horndeski and DHOST) and discuss the optimal strategy for probing each. In many cases, this is driven by whether a specific category violates the equivalence principles (strong or weak). We summarize the general model-independent bounds on each screening category that have been derived in the literature.

scholarly journals RECONSTRUCTING DARK ENERGY

2006 ◽  
Vol 15 (12) ◽  
pp. 2105-2132 ◽  
Author(s):  
VARUN SAHNI ◽  
ALEXEI STAROBINSKY
Keyword(s):  
Dark Energy ◽  
Energy Density ◽  
Current Data ◽  
Effective Equation ◽  
Dark Energy Density ◽  
Future Directions ◽  
Reconstruction Methods ◽  
History Of ◽  
Model Independent ◽  
Constant Energy Density

This review summarizes recent attempts to reconstruct the expansion history of the universe and to probe the nature of dark energy. Reconstruction methods can be broadly classified into parametric and non-parametric approaches. It is encouraging that, even with the limited observational data currently available, different approaches give consistent results for the reconstruction of the Hubble parameter H(z) and the effective equation of state w(z) of dark energy. Model independent reconstruction using current data allows for modest evolution of dark energy density with redshift. However, a cosmological constant (= dark energy with a constant energy density) remains an excellent fit to the data. Some pitfalls to be guarded against during cosmological reconstruction are summarized and future directions for the model independent reconstruction of dark energy are explored.

scholarly journals A model-independent analysis of $$b{\rightarrow }s\mu ^{+}\mu ^{-}$$transitions with GAMBIT ’s FlavBit

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
Jihyun Bhom ◽  
Marcin Chrzaszcz ◽  
Farvah Mahmoudi ◽  
Markus T. Prim ◽  
Pat Scott ◽  
...  
Keyword(s):  
Standard Model ◽  
Neutral Current ◽  
Current Data ◽  
Operator Product ◽  
Beyond The Standard Model ◽  
Vector Coupling ◽  
Independent Analysis ◽  
The Standard Model ◽  
Model Independent ◽  
Best Fit

AbstractThe search for flavour-changing neutral current effects in B-meson decays is a powerful probe of physics beyond the Standard Model. Deviations from SM behaviour are often quantified by extracting the preferred values of the Wilson coefficients of an operator product expansion. We use the module of the package to perform a simultaneous global fit of the Wilson coefficients $$C_7$$ C 7 , $$C_9$$ C 9 , and $$C_{10}$$ C 10 using a combination of all current data on $$b{\rightarrow }s\mu ^{+}\mu ^{-}$$ b → s μ + μ -  transitions. We further extend previous analyses by accounting for the correlated theoretical uncertainties at each point in the Wilson coefficient parameter space, rather than deriving the uncertainties from a Standard Model calculation. We find that the best fit deviates from the SM value with a significance of 6.6$$\sigma $$ σ . The largest deviation is associated with a vector coupling of muons to b and s quarks.

scholarly journals Maximum latent heat of neutron star matter without GR

2022 ◽  
Vol 258 ◽  
pp. 07007
Author(s):  
Eva Lope-Oter
Keyword(s):  
Neutron Star ◽  
Latent Heat ◽  
Modified Gravity ◽  
Current Knowledge ◽  
Neutron Star Matter ◽  
First Order ◽  
Model Independent ◽  
Dynamical Quantity ◽  
First Order Phase ◽  
Hadron Model

We show how the specific latent heat is relevant to characterize the first-order phase transitions in neutron stars. Our current knowledge of this dynamical quantity strongly depends on the uncertainty bands of Chiral Perturbation Theory and of pQCD calculations and can be used to diagnose progress on the equation of state. We state what is known to be hadron-model independent and without feedback from neutron star observations and, therefore, they can be used to test General Relativity as well as theories beyond GR, such as modified gravity.

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