arXiv subjects

Luigi Delle Rose

Publications and source records attributed to Luigi Delle Rose.

At least 19 recordsLinked to original sources

arXiv2026

Resonant Di-Higgs Searches in $b\bar{b}τ^+τ^-$ at HL-LHC: Supersymmetry versus Compositeness Benchmarks

We explore the scope of the High-Luminosity Large Hadron Collider (HL-LHC) in testing Standard Model (SM) di-Higgs production and decay into $2b2τ$ final states in the context of two viable theories of the Electro-Weak (EW) scale: Supersymmetry and Compositeness. Specifically, we target minimal model realisations of these two scenarios that enable the resonant process $gg\to H\to hh\to b\bar{b} τ^+τ^-$, where $h$ is the SM-like Higgs state and $H$ a heavier CP-even companion, with the $τ$'s decaying hadronically. This is realised within the Next-to-Minimal Supersymmetric SM and the Composite 2-Higgs Doublet Model, respectively. Using two illustrative benchmark points, after performing a thorough detector-level Monte Carlo (MC) analysis exploiting new observables, we show that, in the former case, there is more moderate sensitivity, owing to large backgrounds, whereas, in the latter case, substantial scope for discovery exists, in a background free environment.

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arXiv2026

Electro-Weak Phase Transitions and Collider Signals in the Aligned 2-Higgs Doublet Model

We show that the Aligned 2-Higgs Doublet Model (A2HDM) is a framework able to simultaneously accommodate strong first order electro-weak phase transitions, in turn generating detectable gravitational waves as well as a variety of Higgs boson signals (involving both the Standard Model state and its companions, both neutral and charged) accessible at the Large Hadron Collider (LHC). We map the corresponding expanse of parameter space where such a phenomenology is realised in terms of the relative values of the masses of the discovered Higgs boson and the extended Higgs sector states of this model: two neutral ones (a CP-even and a CP-odd) plus a pair of charged ones. We find that both the Laser Interferometer Space Antenna experiment and High-Luminosity LHC can test such a scenario within their lifetime. This study thus sets the stage for a two-prong complementary approach able to scrutinise the extended Higgs sector of the A2HDM in both its high and low temperature manifestations.

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arXiv2026

Thermal Masses and Bubble-Wall Friction in Cosmological Phase Transitions

Bubble-wall friction controls the dynamics of first-order cosmological phase transitions. In Boltzmann-equation approaches, a major uncertainty arises from infrared gauge bosons, whose contribution is artificially enhanced in the massless approximation. We study the impact of thermal masses by including them consistently in both the Liouville operator and the collision integrals. Thermal masses suppress the source term for out-of-equilibrium perturbations while also reducing interaction rates. These effects largely cancel for top quarks, giving only percent-level changes, but they strongly suppress the infrared gauge-boson contribution, shifting the dominant momenta to scales of order the temperature. As a result, gauge bosons become subleading and wall velocities are close to those obtained from top-quark friction alone. We illustrate this in the singlet-extended Standard Model. Our results show that thermal masses reduce the sensitivity of friction calculations to the poorly controlled infrared sector of the plasma.

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arXiv2026

Deeply virtual meson production at HERA and at the EIC within the Color Glass Condensate EFT

Continuing our previous study of Deeply Virtual Meson Production (DVMP) at twist-3 accuracy, we derive compact expressions for all helicity amplitudes. We perform a phenomenological analysis of the helicity-amplitude ratio $\mathcal{A}^{11}/\mathcal{A}^{00}$ and of the spin-density matrix element $r_{00}^{04}$ within the Color Glass Condensate framework. Small-$x$ evolution is incorporated by numerically solving the running-coupling-and-collinearly-improved Balitsky-Kovchegov and Balitsky-Fadin-Kuraev-Lipatov equations with the McLerran-Venugopalan model as the initial condition. By capturing a relevant subset of next-to-leading order corrections, we provide the most theoretically accurate description of these observables to date. Our results are compared to HERA data, and predictions are presented for electron-lead collisions at the future Electron-Ion Collider. We discuss the impact of non-linear effects at low photon virtuality and the role of genuine higher-twist contributions associated with light vector meson distribution amplitudes, corresponding to higher-Fock-state components of the projectile.

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arXiv2026

Searches for Extra Higgs Bosons using $t\bar{t}+$Higgs{$(\to b\bar b)$} Events within 2HDMs: Direct versus Indirect Probes

We study the possibility of establishing the production of additional Higgs states in the process $gg,q\bar q\to t\bar t Φ$, where $Φ$ = $H_{2,3}$, with $H_2$ being CP-even and $H_3$ being CP-odd, at the Large Hadron Collider (LHC), by solely exploiting the kinematic features of the reconstructed $t\bar t$ system. We adopt as reference theoretical framework a generic CP-Conserving 2-Higgs Doublet Model (2HDM), which also accommodate a Standard Model (SM)-like Higgs state $H_1$. We show that the masses $m_{H_{2,3}}$ exhibit clear correlations with the $t\bar{t}$ system properties and could, in principle, be extracted from these. Moreover, the CP properties of the $H_{2,3}$ states can be determined, even when both states are produced simultaneously. We then compare the results produced using this method with those obtained from a full kinematic reconstruction of the $H_{2,3}$ decays in the most studied $b\bar b$ channel (we take $m_{H_{2,3}}< 2m_t$), thus proving the superiority of the approach here proposed. This paves the way to both the discovery and characterization of additional Higgs states produced {\sl inclusively} in association with top-antitop quark pairs, thereby dispensing of the complications intrinsic to the {\sl exclusive} reconstruction of such states from their decay products. We test this by establishing the sensitivity of our approach in the case of a Composite 2HDM (C2HDM), describing the Higges as pseudo-Nambu Goldstone Bosons (pNGBs) and naturally predicting Higgs mass spectra in the range of sensitivity of the described analysis.

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arXiv2025

Probing the Electroweak Phase Transition in the Dark Sector

We study an extension of the Standard Model with a dark SU(2) gauge group, where a dark scalar doublet interacts with the Standard Model Higgs through a portal coupling, inducing mixing after symmetry breaking. A custodial symmetry ensures the stability of the dark gauge bosons, making them viable dark matter candidates. Scanning the parameter space of the model under collider and astrophysical constraints, we find regions that yield the observed relic density and strong first-order phase transitions. The resulting gravitational-wave signals fall within the reach of upcoming space-based detectors.

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arXiv2025

Phase transitions and gravitational waves in a non-abelian vector dark matter scenario

We study a scenario where the Standard Model is extended by a SU(2) gauge group in the dark sector. The three associated dark gauge bosons are stabilised via a custodial symmetry triggered by an additional dark SU(2) scalar doublet, thus making them viable dark-matter candidates. After considering the most recent constraints for this model, we analyse the phase transition dynamics and compute the power spectrum of resulting stochastic gravitational-wave background. Finally, we find regions of the parameter space yielding the observed dark-matter relic density while also leading to strong enough phase transition with an associated gravitational-wave signal reaching the sensitivity of future space-based gravitational-wave detector, such as LISA, DECIGO, BBO, TianQin or Taiji.

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arXiv2025

Matching NLL to NLO in Higgs and Z plus jet at the LHC and FCC

We present updated predictions for rapidity and transverse-momentum spectra in Higgs-plus-jet production at proton colliders, combining NLO fixed-order QCD with next-to-leading energy-logarithmic resummation. Preliminary results for the $Z$-boson case are also discussed. Our study underscores the importance of improving fixed-order predictions for Higgs- and $Z$-plus-jet observables to meet the precision demands of Higgs and electroweak measurements at the LHC and future FCC energies.

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arXiv2025

Bubble wall velocity with out-of-equilibrium corrections

We study how out-of-equilibrium effects modify the steady-state propagation of bubble walls during a cosmological first-order electroweak phase transition. Going beyond the local thermal equilibrium approximation, we numerically solve the coupled system of scalar field, hydrodynamic and Boltzmann equations using a spectral algorithm that allows a first-principle treatment of the collision integral. This approach enables a quantitative assessment of non-equilibrium perturbations in the plasma and their backreaction on the wall motion. Focusing on the singlet extension of the Standard Model as a minimal benchmark scenario, we find that out-of-equilibrium corrections substantially enhance the effective friction on the expanding front, leading to slower wall velocities and broader wall profiles compared to the equilibrium case. These modifications have significant implications for cosmological observables. For instance, they enhance the efficiency of electroweak baryogenesis, thus improving the viability of baryon asymmetry generation within realistic parameter regions that can also be probed by future gravitational wave interferometers.

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arXiv2025

Slaying Axion-Like Particles via Gravitational Waves and Primordial Black Holes from Supercooled Phase Transition

We study the formation of primordial black holes (PBHs) from density fluctuations due to supercooled phase transitions (PTs) triggered in an axion-like particle (ALP) model. We find that the mass of the PBHs is inversely correlated with the ALP decay constant $f_a$. For instance, for $f_a$ varying from ${\cal O}$(100 MeV) to ${\cal O}$($10^{12}$ GeV), the PBH mass varies between $(10^{3} - 10^{-24}) M_{\odot}$. We then identify the ALP parameter space where the PBH can account for the entire (or partial) dark matter fraction of the Universe, in a single (multi-component) dark matter scenario, with the ALP being the other dark matter candidate. The PBH parameter space ruled out by current cosmological and microlensing observations can thus be directly mapped onto the ALP parameter space, thus providing new bounds on ALPs, complementary to the laboratory and astrophysical ALP constraints. Similarly, depending on the ALP couplings to other Standard Model particles, the ALP constraints on $f_a$ can be translated into a lower bound on the PBH mass scale. Moreover, the supercooled PT leads to a potentially observable stochastic gravitational wave (GW) signal at future GW observatories, such as aLIGO, LISA and ET, that acts as another complementary probe of the ALPs, as well as of the PBH dark matter. Finally, we show that the recent NANOGrav signal of stochastic GW in the nHz frequency range can be explained in our model with $f_a\simeq (10~{\rm GeV}-1~{\rm TeV})$.

astro-ph.CO↗

arXiv2025

Electroweak Phase Transition and Bubble Wall Velocity in Local Thermal Equilibrium

The dynamics of the electroweak phase transition in the early universe has profound implications for cosmology and particle physics. We systematically study the steady-state dynamics of bubble walls in scenarios where the transition is first order within three representative beyond the Standard Model frameworks, characterised by the presence of an additional scalar in different electroweak representations. Focusing on the local thermal equilibrium regime, we numerically solve the coupled scalar and hydrodynamic equations to extract key properties of the phase transition front: the wall velocity, width, plasma and field profiles. Remarkably, we find a near-universal behaviour across models when expressed in terms of thermodynamic quantities, that can be captured by simple fitting functions, useful for phenomenological applications. These results also provide an upper bound on the bubble velocity and represent the first necessary step for the full inclusion of out-of-equilibrium effects.

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arXiv2025

The real corrections to the Higgs impact factor at next-to-leading order with finite top mass

This work presents the computation of real corrections to the impact factor for forward Higgs boson production, preserving the full dependence on the top-quark mass. The results are shown to align with the BFKL factorization framework, particularly in reproducing the expected rapidity divergence. Additionally, the subtraction of this divergence has been demonstrated using the appropriate counterterm within the BFKL scheme. In the infinite-top-mass limit, our findings reproduce the previously established result.

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arXiv2024

Composite 2-Higgs Doublet Model: Strong Effects on Higgs Pair Production

We show how effects of compositeness emerging in a Composite 2-Higgs Doublet Model can enter Standard Model (SM)-like Higgs pair production at the Large Hadron Collider in both resonant and non-resonant mode. Such effects can arise from modified trilinear Higgs self-couplings and top-Yukawa couplings as well as from loops of new heavy quarks and additional quartic Higgs-fermion interactions. In the resonant case, significant distortions of the Breit- Wigner shape of a new scalar state decaying into the two SM-like Higgs states may occur due to interference effects amongst not only the SM-like diagrams but also those involving the new heavy quarks. In the non-resonant case, a modification of the underlying line-shape and a local maximum at twice a new heavy quark mass appear simultaneously. We quantify these effects by taking into account the relevant theoretical and latest experimental bounds.

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arXiv2024

Electroweak phase transition in a vector dark matter scenario

This study explores the parameter space of a minimal extension of the Standard Model with a non-abelian $SU(2)$ group, in which the gauge bosons are stable and acquire mass through a mechanism of spontaneous symmetry breaking involving a new scalar doublet which interacts with the Higgs boson through a quartic coupling. The exploration aims to assess whether it is possible to obtain a first-order phase transition while ensuring that the gauge bosons are viable dark matter candidates. Theoretical, astrophysical and collider bounds are considered. The results are then tested against the sensitivity of future experiments for the detection of gravitational wave signals.

hep-ph↗

arXiv2024

New calculation of collision integrals for cosmological phase transitions

First order phase transitions in the early universe may have left a variety of experimentally accessible imprints. The dynamics of such transitions is governed by the density perturbations caused by the propagation of the bubble wall in the false vacuum plasma, conveniently described by a Boltzmann equation. The determination of the bubble wall expansion velocity is crucial to determine the experimental signatures of the transition. We report on the first full (numerical) solution to the Boltzmann equation. Differently from traditional ones, our approach does not rely on any ansatz. The results significantly differ from the ones obtained within the fluid approximation and large differences for the friction acting on the bubble wall are found. The wall velocity is calculated in a singlet extension of the Standard Model, including out-of-equilibrium contributions from both the top quark and the electroweak gauge bosons.

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arXiv2024

The next-to-leading order Higgs impact factor at physical top mass: The real corrections

We compute the real corrections to the impact factor for the production of a forward Higgs boson, retaining full top-mass dependence. We demonstrate that the rapidity divergence is the one predicted by the BFKL factorization and perform the explicit subtraction in the BFKL scheme. We show that the IR-structure of the impact factor is the expected one and that, in the infinite-top-mass approximation, the previously known result is recovered. We also verify that the impact factor vanishes when the transverse momenta of the $t$-channel Reggeon goes to zero, in agreement with its gauge-invariant definition, exploiting the $m_t \rightarrow \infty$ expansion up to the next-to-next-to-leading order.

hep-ph↗

arXiv2024

Higgs production at NLL accuracy in the BFKL approach

Precision physics in the Higgs sector has been one of the main challenges of particle physics in the recent years. The pure fixed-order calculations entering the collinear factorization framework, which have been pushed up to next-cube-leading-order, are not able to describe the entire kinematic spectrum. In particular sectors, they have to be necessarily enhanced by all-order resummations. In the so-called semi-hard regime, large energy-type logarithms spoil the perturbative convergence of the series and must be resummed to all orders. This resummation is a core ingredient for a correct description of the inclusive hadroproduction of a forward Higgs boson in the limit of small Bjorken $x$, as well as for a precision study of inclusive forward emissions of a Higgs boson in association with a backward identified object. A complete resummation for these processes can be achieved at the at next-to-leading logarithmic accuracy thanks to the Balitsky-Fadin-Kuraev-Lipatov approach. In the present work we present and discuss a series of recent phenomenological results within a partial next-to-leading accuracy. They include the analysis of rapidity and azimuthal-angle differential rates for Higgs plus jet and Higgs plus charm reactions in forward and ultraforward directions of rapidity at the LHC.

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arXiv2024

Towards Higgs and $Z$ boson plus jet distributions at NLL/NLO$^+$

We present novel predictions for rapidity and transverse-momentum distributions sensitive to the emission of a Higgs boson accompanied by a jet in proton collisions, calculated within the NLO fixed order in QCD and matched with the next-to leading energy-logarithmic accuracy. We also highlight first advancements in the extension of our analysis to the $Z$-boson case. We come out with the message that the improvement of fixed-order calculations on Higgs- and $Z$-boson plus jet distributions is a required step to reach the precision level of the description of observables relevant for Higgs and electroweak physics at current LHC energies and nominal FCC ones.

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