ACAntonio Costantini

Antonio Costantini

*This is an algorithmically generated author record based on publicly available information.

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Previous Organizations / Institutes

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Antonio Costantini has a total of 51 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    The Effective Vector Boson Approximation in High-Energy Muon Collisions

    by Richard Ruiz, Antonio Costantini, Fabio Maltoni, Olivier Mattelaer

    Due to the inclination for forward gauge radiation, lepton colliders beyond a few TeV are effectively electroweak (EW) boson colliders, suggesting the treatment of EW bosons as constituents of high-energy leptons. In the context of a muon collider, we revisit the validity of $W$ and $Z$ parton distribution functions (PDFs) at leading order in $2\to n$ process. We systematically investigate universal and quasi-universal power-law and logarithmic corrections that arise when deriving (polarized) weak boson PDFs in the collinear limit. We go on to survey a multitude of $2\to n$ processes at $\sqrt{s}=2-30$ TeV via polarized and unpolarized EW boson fusion/scattering. To conduct this study, we report a public implementation of the Effective $W/Z$ and Weizs\"acker-Williams Approximations, which we collectively call the Effective Vector Boson Approximation, into the Monte Carlo event generator \texttt{MadGraph5\_aMC@NLO}. This implementation lays the groundwork for developing matrix-element matching prescriptions involving EW parton showers and renormalized EW PDFs. To further with this agenda, we give recommendations on using $W/Z$ PDFs.

  • Open Access

    The Effective Vector Boson Approximation in high-energy muon collisions

    by Richard Ruiz, Antonio Costantini, Fabio Maltoni, Olivier Mattelaer

    Due to the inclination for forward gauge radiation, lepton colliders beyond a few TeV are effectively electroweak (EW) boson colliders, suggesting the treatment of EW bosons as constituents of high-energy leptons. In the context of a muon collider, we revisit the validity of W and Z parton distribution functions (PDFs) at leading order in 2 → n process. We systematically investigate universal and quasi-universal power-law and logarithmic corrections that arise when deriving (polarized) weak boson PDFs in the collinear limit. We go on to survey a multitude of 2 → n processes at $$ \sqrt{s} $$ s = 2–30 TeV via polarized and unpolarized EW boson fusion/scattering. To conduct this study, we report a public implementation of the Effective W/Z and Weizsäcker-Williams Approximations, which we collectively call the Effective Vector Boson Approximation, into the Monte Carlo event generator MadGraph5_aMC@NLO. This implementation lays the groundwork for developing matrix-element matching prescriptions involving EW parton showers and renormalized EW PDFs. To further with this agenda, we give recommendations on using W/Z PDFs.


  • Open Access

    Vector boson scattering processes: Status and prospects

    by Diogo Buarque Franzosi, Michele Gallinaro, Richard Ruiz, Thea K. Aarrestad, Flavia Cetorelli, Mauro Chiesa, Antonio Costantini, Ansgar Denner, Stefan Dittmaier, Robert Franken, et al.


  • Open Access

    Non-Leptonic Decays of Bileptons

    by Gennaro Corcella, Claudio Coriano, Antonio Costantini, Paul H. Frampton

    We provide a detailed analysis of the decays of doubly-charged bilepton gauge bosons $Y^{\pm\pm}$, as predicted in models based on a $SU(3)_C\times SU(3)_L\times U(1)_X$ symmetry. In addition to the decay modes into same-sign lepton pairs, which were already investigated in scenarios wherein each branching ratio was about one third, there are, depending on the mass spectrum, possible non-leptonic decays which reduce the leptonic rates. These non-leptonic decays are typically into a light quark (antiquark) and a heavy TeV-scale antiquark (quark), which carries double lepton number and decays via virtual bileptons. We choose two benchmark points to represent the particle spectrum and present a phenomenological analysis of such decays. We find that, while the LHC statistics are too low, even in the high-luminosity phase, they can lead to a visible signal at a future 100 TeV hadron collider (FCC-$hh$). A more exhaustive exploration with a rigorous inclusion of tagging efficiencies, detector simulations and higher-order corrections to the partonic cross section, aiming at assessing the reach of LHC and FCC-$hh$ for bileptons as a function of the model parameters, as well as a recast of four-top searches in terms of the bilepton model, are deferred to future work.

  • Open Access

    (New) Physics at a multi-TeV $μ$ Collider

    by Antonio Costantini

    We present the results of the physics reach of a multi-TeV muon collider for popular models of physics beyond the Standard Model. We include also details about a model predicting the scalar dark matter in the spectrum. Finally we present some preliminary results about the Effective Vector Approximation and its implementation in the Monte Carlo generator {\sc MadGraph5\_aMC@NLO}.

  • Open Access

    Vector-like quarks decaying into singly and doubly charged bosons at LHC

    by Gennaro Corcella, Antonio Costantini, Margherita Ghezzi, Luca Panizzi, Giovanni Marco Pruna, Jakub Šalko

    We investigate the production of vector-like quarks with charge 5/3 at the LHC and their subsequent decays into new singly or doubly charged bosons plus a heavy quark (top or bottom). In particular, we explore final states with same-sign di-leptons (electron or muon pairs), with the leptons coming from the decay of the new bosons and, in the case of production of singly charged bosons, from top quarks as well. These processes are predicted by classes of models based on extensions of the gauge group of the Standard Model, such as the 331 Model, where the electroweak symmetry is described by SU(3)L × U(1)X, X being a new abelian charge. For this purpose, a CMS search for vector-like partners with charge 5/3 decaying into Wt is recast to obtain model-independent bounds and projected reaches at future luminosity stages of the LHC. The results are then interpreted as mass bounds for the new particles predicted in the 331 Model and as a constraint on the scale of its spontaneous symmetry breaking. The complete set of model-independent results are provided as recast efficiencies, to allow for reinterpretation in different scenarios.


  • Open Access

    Vector-like quarks decaying into singly and doubly charged bosons at LHC

    by Gennaro Corcella, Antonio Costantini, Margherita Ghezzi, Luca Panizzi, Giovanni Marco Pruna, Jakub Šalko

    We investigate the production of vector-like quarks with charge $5/3$ at the LHC and their subsequent decays into new singly or doubly charged bosons plus a heavy quark (top or bottom). In particular, we explore final states with same-sign di-leptons (electron or muon pairs), with the leptons coming from the decay of the new bosons and, in the case of production of singly charged bosons, from top quarks as well. These processes are predicted by classes of models based on extensions of the gauge group of the Standard Model, such as the 331 Model, where the electroweak symmetry is described by $SU(3)_L\times U(1)_X$, $X$ being a new abelian charge. For this purpose, a CMS search for vector-like partners with charge 5/3 decaying into $Wt$ is recast to obtain model-independent bounds and projected reaches at future luminosity stages of the LHC. The results are then interpreted as mass bounds for the new particles predicted in the 331 Model and as a constrain on the scale of its spontaneous symmetry breaking. The complete set of model-independent results are provided as recast efficiencies, to allow for reinterpretation in different scenarios.

  • Open Access

    Obscure Higgs boson at colliders

    by Priyotosh Bandyopadhyay, Antonio Costantini

    In this study we consider an extension of the Standard Model with a complex hypercharge zero triplet scalar. In this scenario one of the charged Higgs bosons remains purely triplet and does not couple to the fermions, making it elusive at colliders. Also the physical pseudoscalar is a pure triplet and this purity makes it a suitable dark matter candidate without the need of discrete symmetries, unlike other extensions. The bounds from relic density and direct dark matter search experiments select its mass to be ∼1.35–1.60  TeV. The pure triplet charged Higgs gives rise to displaced signatures and their sensitivity at LHC and MATHUSLA have been studied. The prospects at present and future hadron/muon colliders of such exotic scalars are pointed out by calculating their productions cross section and dominant decay modes. We present also the expected reach for the triplet states at a multi-TeV muon collider.


  • Open Access

    Obscure Higgs boson at Colliders

    by Priyotosh Bandyopadhyay, Antonio Costantini

    In this study we consider an extension of the Standard Model with a complex hypercharge zero triplet scalar. In this scenario one of the charged Higgs bosons remains purely triplet and does not couple to the fermions, making it elusive at colliders. Also the physical pseudoscalar is a pure triplet and this purity makes it a suitable dark matter candidate without the need of discrete symmetries, unlike other extensions. The bounds from relic density and direct dark matter search experiments select its mass to be $\sim 1.35-1.60$ TeV. The pure triplet charged Higgs gives rise to displaced signatures and their sensitivity at LHC and MATHUSLA have been studied. The prospects at present and future hadron/muon colliders of such exotic scalars are pointed out by calculating their productions cross-section and dominant decay modes. We present also the expected reach for the triplet states at a multi-TeV muon collider.

  • Open Access

    Vector boson fusion at multi-TeV muon colliders

    by Antonio Costantini, Federico De Lillo, Fabio Maltoni, Luca Mantani, Olivier Mattelaer, Richard Ruiz, Xiaoran Zhao

    High-energy lepton colliders with a centre-of-mass energy in the multi-TeV range are currently considered among the most challenging and far-reaching future accelerator projects. Studies performed so far have mostly focused on the reach for new phenomena in lepton-antilepton annihilation channels. In this work we observe that starting from collider energies of a few TeV, electroweak (EW) vector boson fusion/scattering (VBF) at lepton colliders becomes the dominant production mode for all Standard Model processes relevant to studying the EW sector. In many cases we find that this also holds for new physics. We quantify the size and the growth of VBF cross sections with collider energy for a number of SM and new physics processes. By considering luminosity scenarios achievable at a muon collider, we conclude that such a machine would effectively be a "high-luminosity weak boson collider," and subsequently offer a wide range of opportunities to precisely measure EW and Higgs coupling as well as to discover new particles.