Person

Francesco Riva

Towards a nonperturbative construction of the S-matrix

Francesco Riva, Matthew Thomas Walters, Brian Quinn Henning

We present a nonperturbative recipe for directly computing the S-matrix in strongly-coupled QFTs. The method makes use of spectral data obtained in a Hamiltonian framework and can be applied to a wide range of theories, including potentially QCD. We demons ...

Springer Nature2023

IR side of positivity bounds

Francesco Riva, Marc Riembau Saperas, Brando Bellazzini

We show how calculable IR loop effects impact positivity bounds in effective field theories with causal and unitary UV completions. We identify infrared singularities that appear in dispersion relations at |t| less than or similar to m(2). In the massless ...

American Physical Society2022

Positive moments for scattering amplitudes

Riccardo Rattazzi, Francesco Riva, Marc Riembau Saperas, Brando Bellazzini

We find the complete set of conditions satisfied by the forward 2 -> 2 scattering amplitude in unitary and causal theories. These are based on an infinite set of energy dependent quantities (the arcs) which are dispersively expressed as moments of a positi ...

American Physical Society2021

What is the gamma gamma resonance at 750 GeV?

Riccardo Rattazzi, Francesco Riva, Roberto Franceschini, Michele Redi, Riccardo Torre

Run 2 LHC data show hints of a new resonance in the diphoton distribution at an invariant mass of 750 GeV. We analyse the data in terms of a new boson, extracting information on its properties and exploring theoretical interpretations. Scenarios covered in ...

Springer Nature2016

Vices and virtues of Higgs effective field theories at large energy

Francesco Riva, Da Liu

We study constraints on new physics from Higgs production at the LHC in the context of an effective field theory (EFT), focusing on Higgs searches in HV (V = W, Z) associated production which are particularly sensitive to the high-energy behavior of certai ...

American Physical Society2015

Leading effects beyond the standard model

Francesco Riva

Using the predictive power of the effective field theory approach, we present a physical parametrization of the leading effects beyond the standard model (BSM), which gives us at present the best way to constrain heavy new physics at low energies. We show ...

American Physical Society2015

Model-independent precision constraints on dimension-6 operators

Francesco Riva

We discuss electroweak precision constraints on dimension-6 operators in the effective theory beyond the standard model. We identify the combinations of these operators that are constrained by the pole observables (the W and Z masses and on-shell decays) a ...

Springer Nature2015

Towards the ultimate SM fit to close in on Higgs physics

Francesco Riva

With the discovery of the Higgs at the LHC, experiments have finally addressed all aspects of the Standard Model (SM). At this stage, it is important to understand which windows for beyond the SM (BSM) physics are still open, and which are instead tightly ...

Springer Nature2014

Composite charge 8/3 resonances at the LHC

Francesco Riva, Thibaud Vantalon

In composite Higgs models with partial compositeness, the small value of the observed Higgs mass implies the existence of light fermionic resonances, the top partners, whose quantum numbers are determined by the symmetry (and symmetry breaking) structure o ...

Springer Nature2014

(Re-)inventing the relativistic wheel: gravity, cosets, and spinning objects

Francesco Riva, Alexander Monin, Solomon G Shamsuddin Osman Endlich

Space-time symmetries are a crucial ingredient of any theoretical model in physics. Unlike internal symmetries, which may or may not be gauged and/or spontaneously broken, space-time symmetries do not admit any ambiguity: they are gauged by gravity, and an ...

Springer Nature2014