arXiv subjects

Adriano Cherchiglia

Publications and source records attributed to Adriano Cherchiglia.

At least 19 recordsLinked to original sources

arXiv2026

Disentangling Charged-Current Scalar NSI from the Solar Sector at JUNO

We constrain charged-current scalar non-standard interaction with reactor antineutrinos within a quantum field theory framework of neutrino oscillations. We derive an analytical expression up to $\mathcal{O}(\varepsilon^{4})$ for the electron antineutrino survival probability including scalar NSI contributions, and show that these effects induce spectral distortions that admit a large mixing angle solution for $θ_{12}$. Using the 59.1-day and preliminary 207.2-day JUNO datasets, we obtain the first neutrino-oscillation determination of NSI parameters individually, rather than in a flavor-summed combination, from reactor experiments. Assuming one year of data taken, we show that the only solar sector analysis breaks the degeneracy with the solar mixing angle at $3σ$ of C.L.

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arXiv2026

From DUNE Sensitivities to UV Models: Implications of Flavour Constraints

Future neutrino experiments, in particular DUNE, are expected to probe signals of new physics. These effects can be conveniently parametrized in terms of Wilson coefficients in the LEFT, with direct connection to non-standard interactions at production, propagation and detection in the QFT formalism. We revisit the apparent sensitivity of DUNE to semileptonic electron--tau interactions within the Standard Model Effective Field Theory. We show that the vector combination controlling the $ε_{eτ}$ NSI is precisely the combination entering $τ\to eω$. Therefore, within the dimension-six vector subspace considered in this work, an operator cancellation that suppresses the tau-decay amplitude also suppresses the corresponding NSI. As a concrete example, we focus on the lepton-flavour-violating semileptonic coefficient $(C^{(1)}_{\ell q,1311})$. We find the bound $8.1\times10^{-3}\,{\rm TeV}^{-2}$ at $90\%$ confidence level, which is one order of magnitude stronger than the DUNE's expected sensitivity. In view of this scenario, we further study one illustrative minimal UV completion, showing that it faces even stronger constraints from other sources, making it very challenging to build UV scenarios with heavy mediators that could produce flavour-changing NSIs observable at DUNE.

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arXiv2025

Alleviating the present tension between T2K and NO$ν$A with nonstandard neutrino interactions

Since neutrino oscillation was observed, several experiments have been built to measure its parameters. NO$ν$A and T2K are two long-baseline experiments dedicated to measuring mainly the mixing angle $θ_{23}$, the charge-parity conjugation phase $δ_{\rm CP}$, and the mass ordering. However, there is a tension in current data. The T2K allowed region is in conflict with the region allowed by NO$ν$A. We propose a nonstandard charged current interaction (CC-NSI) in neutrino production to relieve this tension. The CC-NSI is computed through quantum field theory (QFT) formalism, where we derive perturbative analytical formulae considering CC-NSI in the pion decay. Within this new approach, we can alleviate NO$ν$A and T2K tension for a CC-NSI complex parameters of order $10^{-3}$. We show the new phase has a degeneracy to the Dirac CP phase of the form $δ_{\rm CP} \pm ϕ= 1.5π$ being a possible source of violation of charge-parity symmetry.

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arXiv2025

Maximal value for trilinear Higgs coupling in a 3-3-1 EFT

Recent efforts, both theoretical and experimental, have increasingly focused on the scalar potential of the Standard Model, with a highlight on the trilinear Higgs coupling. This parameter has long been recognized for its potential to test Beyond-Standard-Model (BSM) theories and its significance in understanding early cosmological dynamics. In order to broadly map BSM scenarios, a powerful tool is to devise its effective field theory (EFT) version for low-energies. In this work, we obtain a consistent EFT for a class of models based on the gauge group $SU(3)_c\times SU(3)_L\times U(1)_Y$. After properly matching the UV-complete theory at one-loop, we show that the EFT is a Two-Higgs-Doublet Model (2HDM), where some of the quartic couplings are naturally small. By imposing bounds from electroweak precision observables, collider, flavor, as well as theoretical considerations, we obtain that the maximum value of the trilinear Higgs coupling is more than four times larger than the SM prediction, potentially testable at the LHC Hi-Lumi upgrade and other future colliders. Moreover, we find that such large values are only attainable if one considers an out-of-alignment scenario, even if the deviation is very small.

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arXiv2025

Neutrino Theory in the Precision Era

This document summarises discussions on future directions in theoretical neutrino physics, which are the outcome of a neutrino theory workshop held at CERN in February 2025. The starting point is the realisation that neutrino physics offers unique opportunities to address some of the most fundamental questions in physics. This motivates a vigorous experimental programme which the theory community fully supports. \textbf{A strong effort in theoretical neutrino physics is paramount to optimally take advantage of upcoming neutrino experiments and to explore the synergies with other areas of particle, astroparticle, and nuclear physics, as well as cosmology.} Progress on the theory side has the potential to significantly boost the physics reach of experiments, as well as go well beyond their original scope. Strong collaboration between theory and experiment is essential in the precision era. To foster such collaboration, \textbf{we propose to establish a CERN Neutrino Physics Centre.} Taking inspiration from the highly successful LHC Physics Center at Fermilab, the CERN Neutrino Physics Centre would be the European hub of the neutrino community, covering experimental and theoretical activities.

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arXiv2025

Addressing $γ_5$ in Nondimensional Regularizations: A Case Study on the Bumblebee Model

We examine the subtleties of regularization schemes in four-dimensional space ($4S$), related in particular to the introduction of the $γ_5$ matrix. To illustrate we use a "Bumblebee" model featuring dynamically induced Lorentz symmetry violation. The analysis centers on how different regularization methods affect the solutions to the gap equation in this model. We highlight the resolution of ambiguities associated with the $γ_5$ matrix in ultraviolet divergent integrals by employing an enhanced Implicit Regularization (IREG) method. This method extends IREG to a quasi-four-dimensional space, $Q4S = 4S \oplus X$, drawing parallels with the consistent approach of Dimensional Reduction (DRED). Comparative analysis is conducted against results from the 't Hooft-Veltman regularization scheme, conventional IREG in strict $4S$, and sharp momentum cutoff techniques. Our results illustrate a scheme to compute $γ_5$ interactions in physical dimension of divergent amplitudes, confirming the approach in [1].

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arXiv2024

Analytical Expressions for Neutrino Oscillation

Research in neutrino physics has been very active, both in experimental advances, with a new generation of detectors in operation and planning, and in theoretical discussions regarding the fundamental nature of the neutrino. This scientific dynamism has attracted many new students to the field. One of the first topics studied in neutrino physics by newcomers is the formalism of neutrino flavor oscillations and its associated phenomenology. We present this work as a compilation of this basic knowledge, through a step-by-step approach that facilitates an efficient understanding of this vast theoretical and experimental landscape.

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arXiv2024

An Implicit Regularization Approach to Chiral Models

The decays of the Z boson and CP-even or CP-odd scalar bosons into quark-antiquark pairs have been calculated at NLO in the framework of Implicit Regularization (IReg) , which operates strictly in the physical dimension and complies with the BPHZ procedure. The presence of the γ5 matrix is dealt without the need of gauge symmetry restoring counterterms and the Kinoshita-Lee-Nauenberg (KLN) theorem is verified. The results are compared to the ones obtained in the Dimensional Reduction scheme (DRed).

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arXiv2024

DUNE potential as a New Physics probe

Neutrino experiments, in the next years, aim to determine with precision all the six parameters of the three-neutrino standard paradigm. The complete success of the experimental program is, nevertheless, attached to the non-existence (or at least smallness) of Non-Standard Interactions (NSI). In this work, anticipating the data taken from long-baseline neutrino experiments, we map all the weakly coupled theories that could induce sizable NSI, with the potential to be determined in these experiments, in particular DUNE. Once present constraints from other experiments are taken into account, in particular charged-lepton flavor violation, we find that only models containing leptoquarks (scalar or vector) and/or neutral isosinglet vector bosons are viable. We provide the explicit matching formulas connecting weakly coupled models and NSI, both in propagation and production. Departing from the weakly coupled completion with masses at TeV scale, we also provide a global fit on all NSI for DUNE, finding that NSI smaller than $10^{-2}$ cannot be probed even in the best-case scenario.

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arXiv2023

Infrared Subtleties and Chiral Vertices at NLO: An Implicit Regularization Analysis

We employ implicit regularization (IReg) in quark-antiquark decays of the Z, or of a scalar (CP-even or odd) boson at NLO, and compare with dimensional schemes to reveal subtleties involving infrared divergence cancellation and $γ_5$-matrix issues. Besides the absence of evanescent fields in IReg, such as $ε$-scalars required in certain schemes that operate partially in the physical dimension, we verify that our procedure preserves gauge invariance in the presence of the $γ_5$ matrix without requiring symmetry preserving counterterms while the amplitude is infrared finite as required by the KLN theorem.

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arXiv2023

A step towards a consistent treatment of chiral theories at higher loop order: the abelian case

As recently pointed out, regularization schemes defined in four-dimensions may also face inconsistencies in the presence of chiral fermions. In this work, we extend this analysis to two-loop order. Adopting the implicit regularization as working arena, we discuss in detail how a consistent version of the method can be envisaged, and present many of the subtleties that appear at two-loop order using an abelian chiral model as working example.

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arXiv2023

Higgs boson decay into gluons in a 4D regularization: IR cancellation without evanescent fields to NLO

Higgs decay using an effective Higgs-Yang-Mills interaction in terms of a dimension five operator as well as usual QCD interactions is revisited in the context of Implicit Regularization (IReg) and compared with conventional dimensional regularization (CDR), four dimensional helicity (FDH) and dimensional reduction (DRED) schemes. The decay rate for $H \rightarrow gg(g)$ is calculated in this strictly four-dimensional set-up to $α_s^3$ order in the strong coupling. Moreover we include joint processes that contribute at the same perturbative order in the real emission channels consisting of 3 gluons as well as gluon quark-antiquark final states with light (zero mass) quarks. Unambiguous identification and separation of UV from IR divergences is achieved putting at work the renormalization group scale relation inherent to the method. UV singularities are removed as usual by renormalization, the IR divergences are cancelled due to the method's compliance with the Kinoshita-Lee-Nauenberg (KLN) theorem. Most importantly, we verify that no evanescent fields such as $ε$-scalars need be introduced as required by some mixed regularizations that operate partially in the physical dimension.

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arXiv2022

GM2Calc-2 for the 2HDM

GM2Calc is a leading tool for calculating precise contributions to $a_μ$ in the Minimal Supersymmetric Standard Model. In this proceeding we detail GM2Calc version 2 where it is extended so it can calculate two-loop contributions to $a_μ$ in the Two-Higgs Doublet Model (2HDM), based on the work in Ref. [1]. The 2HDM is a simple model, yet it is one of the few single field extensions of the Standard Model which is able to explain the muon $g-2$ anomaly. We demonstrate the powerful and flexible 2HDM capabilities of GM2Calc2, which include the most precise contributions in the literature and allow the user to work in their favourite type of the 2HDM as well as use complex and lepton flavour violating couplings. With its multiple interfaces and input flexibility, GM2Calc2 is a powerful tool both as a standalone code and as part of a larger code toolchain.

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arXiv2022

Two-loop Prediction of the Anomalous Magnetic Moment of the Muon in the Two-Higgs Doublet Model with GM2Calc 2

We present an extension of the GM2Calc software to calculate the muon anomalous magnetic moment ($a_μ^{\text{BSM}}$) in the Two-Higgs Doublet Model. The Two-Higgs Doublet Model is one of the simplest and most popular extensions of the Standard Model. It is one of the few single field extensions that can give large contributions to $a_μ^{\text{BSM}}$. It is essential to include two-loop corrections to explain the long standing discrepancy between the Standard Model prediction and the experimental measurement in the Two-Higgs Doublet Model. The new version GM2Calc 2 implements the state of the art two-loop calculation for the general, flavour violating Two-Higgs Doublet Model as well as for the flavour aligned Two-Higgs Doublet Model and the type I, II, X and Y flavour conserving variants. Input parameters can be provided in either the gauge basis or the mass basis, and we provide an easy to use SLHA-like command-line interface to specify these. Using this interface users may also select between Two-Higgs Doublet Model types and choose which contributions to apply. In addition, GM2Calc 2 also provides interfaces in C++, C, Python and Mathematica, to make it easy to interface with other codes.

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arXiv2021

The muon magnetic moment in the 2HDM: complete two-loop result

We study the ${\text{2HDM}}$ contribution to the muon anomalous magnetic moment $a_μ$ and present the complete two-loop result, particularly for the bosonic contribution. We focus on the Aligned ${\text{2HDM}}$, which has general Yukawa couplings and contains the type I, II, X, Y models as special cases. The result is expressed with physical parameters: three Higgs boson masses, Yukawa couplings, two mixing angles, and one quartic potential parameter. We show that the result can be split into several parts, each of which has a simple parameter dependence, and we document their general behavior. Taking into account constraints on parameters, we find that the full ${\text{2HDM}}$ contribution to $a_μ$ can accommodate the current experimental value, and the complete two-loop bosonic contribution can amount to $(2\cdots 4)\times 10^{-10}$, more than the future experimental uncertainty.

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arXiv2021

Two-loop gauge coupling $β$-function in a four-dimensional framework: the Standard Model case

At present, the gauge coupling $β$-function in the Standard Model (SM) is known up to four-loop order. As most SM calculations, dimensional regularization was employed. Despite its striking success, other regularization schemes have emerged, which aim to stay in the physical dimension as far as possible. In this contribution, we apply Implicit Regularization, a scheme defined in momentum space that complies with BPHZ, to obtain the two-loop gauge coupling $β$-function in the Standard Model. We reproduce the same result obtained when applying dimensional regularization.

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arXiv2021

A brief review of Implicit Regularization and its connection with the BPHZ theorem

Quantum Field Theory, as the keystone of particle physics, has allowed great insights to deciphering the core of Nature. Despite its striking success, by adhering to local interactions, Quantum Field Theory suffers from the appearance of divergent quantities in intermediary steps of the calculation, which encompasses the need for some regularization/renormalization prescription. As an alternative to traditional methods, based on the analytic extension of space-time dimension, frameworks that stay in the physical dimension have emerged, Implicit Regularization is one among them. We briefly review the method, aiming to illustrate how Implicit Regularization complies with the BPHZ theorem, which implies that it respects unitarity and locality to arbitrary loop order.

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arXiv2018

Supercurrent anomaly and gauge invariance in N=1 supersymmetric Yang-Mills theory

We analyse Feynman diagram calculational issues related to the quantum breaking of supercurrent conservation in a supersymmetric non-abelian Yang-Mills theory. For the sake of simplicity, we take a zero mass gauge field multiplet interacting with a massless Majorana spin-$1/2$ field in the adjoint representation of $SU(2)$. We shed light on a long-standing controversy regarding the perturbative evaluation of the supercurrent anomaly in connection with gauge and superconformal symmetry in different frameworks. We find that only superconformal symmetry is unambiguously broken using an invariant four dimensional regularization and compare with the triangle AVV anomaly. Subtleties related to momentum routing invariance in the loops of diagrams and Clifford algebra evaluation inside divergent integrals are also discussed in connection with finite and undetermined quantities in Feynman amplitudes.

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