arXiv subjects

Pietro Slavich

Publications and source records attributed to Pietro Slavich.

At least 19 recordsLinked to original sources

arXiv2026

Revisiting the Higgs-mass calculation in the scale-invariant THDM

We revisit the one-loop calculation of the Higgs-mass spectrum of the scale-invariant THDM, relying on a direct calculation of the relevant Feynman diagrams. We highlight a number of incorrect assumptions in earlier calculations that relied on the effective-potential approach. In contrast with the earlier findings, we show that the one-loop corrections can have an effect of ${\cal O}(10\%)$ on the predictions for the BSM-Higgs masses, and they can also induce non-negligible mixing between the SM-like and BSM states in the neutral-scalar sector.

hep-ph↗

arXiv2025

Two-loop BSM contributions to Higgs pair production in the aligned THDM

We study the impact of the two-loop corrections controlled by the BSM Higgs couplings on the cross section for the production of a pair of SM-like Higgs bosons via gluon fusion in the aligned THDM. To this aim, we reassess the two-loop calculation of $\lambda_{hhh}$, we compute for the first time the two-loop corrections to $\lambda_{hhH}$, and we include the relevant corrections to the Higgs-gluon couplings and to the s-channel propagators entering the $gg \rightarrow hh$ amplitude. We discuss the numerical impact of the two-loop BSM contributions, first on the individual couplings and then on the prediction for the pair-production cross section, in two benchmark scenarios for the aligned THDM.

hep-ph↗

arXiv2024

On the two-loop BSM corrections to $h\longrightarrow \gamma\gamma$ in a triplet extension of the SM

We compute the two-loop BSM contributions to the $h\longrightarrow \gamma\gamma$ decay width in the SM extended with a real triplet of $SU(2)$. We consider scenarios in which the neutral components of doublet and triplet do not mix, so that the lighter neutral scalar $h$ has (at least approximately) SM-like couplings to fermions and gauge bosons. We focus on the two-loop corrections controlled by the quartic scalar couplings, and obtain explicit and compact formulas for the $h \gamma \gamma$ amplitude by means of a low-energy theorem that connects it to the derivative of the photon self-energy w.r.t. the Higgs field. We briefly discuss the numerical impact of the newly-computed contributions, showing that they may be required for a precise determination of $\Gamma[h\rightarrow \gamma \gamma]$ in scenarios where the quartic scalar couplings are large.

hep-ph↗

arXiv2023

On the two-loop BSM corrections to $h\longrightarrowγγ$ in the aligned THDM

We compute the two-loop BSM contributions to the $h\longrightarrow γγ$ decay width in the aligned THDM. We adopt the simplifying assumptions of vanishing EW gauge couplings and vanishing mass of the SM-like Higgs boson, which allow us to exploit a low-energy theorem connecting the $hγγ$ amplitude to the derivative of the photon self-energy w.r.t. the Higgs field. We briefly discuss the numerical impact of the newly-computed contributions, showing that they may be required for a precise determination of $Γ[h\rightarrow γγ]$ in scenarios where the quartic Higgs couplings are large.

hep-ph↗

arXiv2022

Higgs-mass prediction in the NMSSM with heavy BSM particles

We address the prediction for the mass of the SM-like Higgs boson in NMSSM scenarios where all BSM particles, including the singlets, have masses at the TeV scale. We provide a full one-loop computation of the matching condition for the quartic Higgs coupling in the NMSSM, supplemented with the two-loop contributions that involve the strong gauge coupling. We discuss the impact of the one- and two-loop corrections that are specific to the NMSSM on the prediction for the Higgs mass, and propose a method to estimate of the uncertainty associated with the uncomputed higher-order terms. Finally, we illustrate how the measured value of the Higgs mass can be used to constrain some yet-unmeasured parameters of the NMSSM.

hep-ph↗

arXiv2022

W boson mass in minimal Dirac gaugino scenarios

We investigate the conditions for alignment in Dirac Gaugino models with minimal matter content. This leads to several scenarios, including an aligned Dirac Gaugino NMSSM that allows a light singlet scalar. We then investigate the compatibility of minimal Dirac Gaugino models with an enhanced W boson mass, using a new precise computation of the quantum corrections included in the code SARAH 4.15.0.

hep-ph↗

arXiv2022

Higgs-mass constraints on a supersymmetric solution of the muon g-2 anomaly

The prediction for the quartic coupling of the SM-like Higgs boson constrains the parameter space of SUSY models, even in scenarios where all of the new-particle masses are above the scale probed so far by the LHC. We study the implications of the Higgs-mass prediction on a recently-proposed SUSY model that features two pairs of Higgs doublets, and provides a solution to the g-2 anomaly thanks to a suitable enhancement of the muon Yukawa coupling.

hep-ph↗

arXiv2019

Full two-loop QCD corrections to the Higgs mass in the MSSM with heavy superpartners

We improve the determination of the Higgs-boson mass in the MSSM with heavy superpartners, by computing the two-loop threshold corrections to the quartic Higgs coupling that involve both the strong and the electroweak gauge couplings. Combined with earlier results, this completes the calculation of the two-loop QCD corrections to the quartic coupling at the SUSY scale. We also compare different computations of the relation between the quartic coupling and the pole mass of the Higgs boson at the EW scale. We find that the numerical impact of the new corrections on the prediction for the Higgs mass is modest, but comparable to the accuracy of the Higgs-mass measurement at the LHC.

hep-ph↗

arXiv2019

Matching renormalisable couplings: simple schemes and a plot

We discuss different choices that can be made when matching a general high-energy theory -- with the restriction that it should not contain heavy gauge bosons -- onto a general renormalisable effective field theory at one loop, with particular attention to the quartic scalar couplings and Yukawa couplings. This includes a generalisation of the counterterm scheme that was found to be useful in the case of high-scale/split supersymmetry, but we show the important differences when there are new heavy scalar fields in singlet or triplet representations of $SU(2)$. We also analytically compare our methods and choices with the approach of matching pole masses, proving the equivalence with one of our choices. We outline how to make the extraction of quartic couplings using pole masses more efficient, an approach that we hope will generalise beyond one loop. We give examples of the impact of different scheme choices in a toy model; we also discuss the MSSM and give the threshold corrections to the Higgs quartic coupling in Dirac gaugino models.

hep-ph↗

arXiv2019

MSSM Higgs Boson Searches at the LHC: Benchmark Scenarios for Run 2 and Beyond

We propose six new benchmark scenarios for Higgs boson searches in the Minimal Supersymmetric Standard Model. Our calculations follow the recommendations of the LHC Higgs Cross Section Working Group, and benefit from recent developments in the predictions for the Higgs-boson masses and mixing. All of the proposed scenarios are compatible with the most recent results from Run 2 of the LHC. In particular, they feature a scalar with mass and couplings compatible with those of the observed Higgs boson, and a significant portion of their parameter space is allowed by the limits from the searches for SUSY particles and additional Higgs bosons. We define a scenario where all SUSY particles are relatively heavy, and two scenarios with light colorless SUSY particles (charginos, neutralinos and, in one case, staus). In addition, we present two scenarios featuring alignment without decoupling, realized with either the lighter or the heavier scalar being SM-like, and a scenario with CP violation.

hep-ph↗

arXiv2017

Improved determination of the Higgs mass in the MSSM with heavy superpartners

We present several advances in the effective field theory calculation of the Higgs mass in MSSM scenarios with heavy superparticles. In particular, we compute the dominant two-loop threshold corrections to the quartic Higgs coupling for generic values of the relevant SUSY-breaking parameters, including all contributions controlled by the strong gauge coupling and by the third-family Yukawa couplings. We also study the effects of a representative subset of dimension-six operators in the effective theory valid below the SUSY scale. Our results will allow for an improved determination of the Higgs mass and of the associated theoretical uncertainty.

hep-ph↗

arXiv2016

Leading two-loop corrections to the Higgs boson masses in SUSY models with Dirac gauginos

We compute the two-loop O(as*at) corrections to the Higgs boson masses in supersymmetric extensions of the Standard Model with Dirac gaugino masses. We rely on the effective-potential technique, allow for both Dirac and Majorana mass terms for the gluinos, and compute the corrections in both the DRbar and on-shell renormalisation schemes. We give detailed results for the MDGSSM and the MRSSM, and simple approximate formulae valid in the decoupling limit for all currently-studied variants of supersymmetric models with Dirac gluinos. These results represent the first explicit two-loop calculation of Higgs boson masses in supersymmetric models beyond the MSSM and the NMSSM.

hep-ph↗

arXiv2016

Higgs mass predictions of public NMSSM spectrum generators

The publicly available spectrum generators for the NMSSM often lead to different predictions for the mass of the standard model-like Higgs boson even if using the same renormalization scheme and two-loop accuracy. Depending on the parameter point, the differences can exceed 5 GeV, and even reach 8 GeV for moderate superparticle masses of up to 2 TeV. It is shown here that these differences can be traced back to the calculation of the running standard model parameters entering all calculations, to the approximations used in the two-loop corrections included in the different codes, and to different choices for the renormalization conditions and scales. In particular, the importance of the calculation of the top Yukawa coupling is pointed out.

hep-ph↗

arXiv2014

Higgs Mass and Unnatural Supersymmetry

Assuming that supersymmetry exists well above the weak scale, we derive the full one-loop matching conditions between the SM and the supersymmetric theory, allowing for the possibility of an intermediate Split-SUSY scale. We also compute two-loop QCD corrections to the matching condition of the Higgs quartic coupling. These results are used to improve the calculation of the Higgs mass in models with high-scale supersymmetry or split supersymmetry, reducing the theoretical uncertainty. We explore the phenomenology of a mini-split scenario with gaugino masses determined by anomaly mediation. Depending on the value of the higgsino mass, the theory predicts a variety of novel possibilities for the dark-matter particle.

hep-ph↗

arXiv2014

A Fake Split Supersymmetry Model for the 126 GeV Higgs

We consider a scenario where supersymmetry is broken at a high energy scale, out of reach of the LHC, but leaves a few fermionic states at the TeV scale. The particle content of the low-energy effective theory is similar to that of Split Supersymmetry. However, the gauginos and higgsinos are replaced by fermions carrying the same quantum numbers but having different couplings, which we call fake gauginos and fake higgsinos. We study the prediction for the light-Higgs mass in this Fake Split SUSY Model (FSSM). We find that, in contrast to Split or high-scale supersymmetry, a 126 GeV Higgs boson is easily obtained even for arbitrarily high values of the supersymmetry scale. For a supersymmetry scale greater than roughly 100 PeV, the Higgs mass is almost independent of the supersymmetry scale and the stop mixing parameter, while the observed value is achieved for tan beta between 1.3 and 1.8 depending on the gluino mass.

hep-ph↗

arXiv2011

The MSSM with heavy scalars

We perform a comprehensive analysis of the Minimal Supersymmetric Standard Model (MSSM) in the scenario where the scalar partners of the fermions and the Higgs particles (except for the Standard-Model-like one) are assumed to be very heavy and are removed from the low-energy spectrum. We first summarize our determination of the mass spectrum, in which we include the one-loop radiative corrections and resum to all orders the leading logarithms of the large scalar masses, and describe the implementation of these features in the FORTRAN code SuSpect which calculates the masses and couplings of the MSSM particles. We then study in detail the phenomenology of the model in scenarios where the gaugino mass parameters are non-universal at the GUT scale, which leads to very interesting features that are not present in the widely studied case of universal gaugino mass parameters. We discuss the constraints from collider searches and high-precision measurements, the cosmological constraints on the relic abundance of the neutralino candidate for the Dark Matter in the Universe - where new and interesting channels for neutralino annihilation appear - and the gluino lifetime. We then analyze, in the case of non-universal gaugino masses, the decays of the Higgs boson (in particular decays into and contributions of SUSY particles), of charginos and neutralinos (in particular decays into Higgs bosons and photons) and of gluinos, and highlight the differences from the case of universal gaugino masses.

hep-ph↗

arXiv2003

On the two-loop Yukawa corrections to the MSSM Higgs boson masses at large tan(beta)

We complete the effective potential calculation of the two-loop, top/bottom Yukawa corrections to the Higgs boson masses in the Minimal Supersymmetric Standard Model, by computing the O(at^2 + at*ab + ab^2) contributions for arbitrary values of the bottom Yukawa coupling. We also compute the corrections to the minimization conditions of the effective potential at the same perturbative order. Our results extend the existing O(at^2) calculation, and are relevant in regions of the parameter space corresponding to tan(beta) >> 1. We extend to the Yukawa corrections a convenient renormalization scheme, previously proposed for the O(ab*as) corrections, that avoids unphysically large threshold effects associated with the bottom mass and absorbs the bulk of the corrections into the one-loop expression. For large values of tan(beta), the new contributions can account for a variation of several GeV in the lightest Higgs boson mass.

hep-ph↗

arXiv2003

Two-loop corrections to Radiative Electroweak Symmetry Breaking in the MSSM

We study the O(at*as + at^2) two-loop corrections to the minimization conditions of the MSSM effective potential, providing compact analytical formulae for the Higgs tadpoles. We connect these results with the renormalization group running of the MSSM parameters from the grand unification scale down to the weak scale, and discuss the corrections to the Higgs mixing parameter mu and to the running CP-odd Higgs mass mA in various scenarios of gravity-mediated SUSY breaking. We find that the O(at*as) and O(at^2) contributions partially cancel each other in the minimization conditions. In comparison with the full one-loop corrections, the O(at*as + at^2) two-loop corrections significantly weaken the dependence of the parameters mu and mA on the renormalization scale at which the effective potential is minimized. The residual two-loop and higher-order corrections to mu and mA are estimated to be at most 1% in the considered scenarios.

hep-ph↗