Institute for Theoretical Physics

Wang H., Zou Y., Wu Q., Liu X., Li Z.

Gross M., Mambrini Y., Kpatcha E., Olea-Romacho M.O., Roshan R.

We calculate the gravitational waves (GWs) produced by primordial black holes (PBHs) in the presence of the inflaton condensate in the early Universe. Combining the GW production from the evaporation process, the gravitational scattering of the inflaton itself, and the density fluctuations due to the inhomogeneous distribution of PBHs, we propose for the first time a complete coherent analysis of the spectrum, revealing three peaks, one for each source. Three frequency ranges (∼kHz, GHz, and PHz, respectively) are expected, each giving rise to a similar GW peak amplitude ΩGW. We also compare our predictions with current and future GWs detection experiments. Published by the American Physical Society 2025

Gariazzo S., Giarè W., Mena O., Di Valentino E.

Dawson S., Forslund M., Giardino P.P.

Some of the most precise measurements of Higgs boson couplings are from the Higgs decays to 4 leptons, where deviations from the Standard Model predictions can be quantified in the framework of the Standard Model effective field theory (SMEFT). In this work, we present a complete next-to-leading order (NLO) SMEFT electroweak calculation of the rate for H→ℓ+ℓ−Z which we combine with the NLO SMEFT result for Z→ℓ+ℓ− to obtain the NLO rate for the H→4 lepton process in the narrow width approximation. The NLO calculation provides sensitivity to a wide range of SMEFT operators that do not contribute to the rate at lowest order and demonstrates the importance of including correlations between the effects of different operators when extracting limits on SMEFT parameters. We show that the extraction of the Higgs trilinear coupling from the decay H→ℓ+ℓ−Z,Z→ℓ+ℓ− in the narrow width approximation strongly depends on the contributions of other operators that first occur at NLO. Published by the American Physical Society 2025

Naredo-Tuero D., Escudero M., Enrique Fernandez-Martinez, Marcano X., Poulin V.

Cosmological neutrino mass bounds are becoming increasingly stringent. The latest limit within ΛCDM from Planck 2018+ACT lensing+DESI is ∑mν<0.072  eV at 95% CL, very close to the minimum possible sum of neutrino masses (∑mν>0.06  eV), hinting at vanishing or even “negative” cosmological neutrino masses. In this context, it is urgent to carefully evaluate the origin of these cosmological constraints. In this paper, we investigate the robustness of these results in three ways: (i) we check the role of potential anomalies in Planck CMB and DESI BAO data; (ii) we compare the results for frequentist and Bayesian techniques, as very close to physical boundaries subtleties in the derivation and interpretation of constraints can arise; (iii) we investigate how deviations from ΛCDM, potentially alleviating these anomalies, can alter the constraints. From a profile likelihood analysis, we derive constraints in agreement at the ∼10% level with Bayesian posteriors. We find that the weak preference for negative neutrino masses is mostly present for Planck 18 data, affected by the well-known “lensing anomaly.” It disappears when the new Planck 2020 HiLLiPoP is used, leading to significantly weaker constraints. Additionally, the pull toward negative masses in DESI data stems from the z=0.7 bin, which contains a BAO measurement in ∼3σ tension with Planck expectations. Without this bin, and in combination with HiLLiPoP, the bound relaxes to ∑mν<0.11  eV at 95% CL. The recent preference for dynamical dark energy alleviates this tension and further weakens the bound. As we are at the dawn of a neutrino mass discovery from cosmology, it will be very exciting to see if this trend is confirmed by future data. Published by the American Physical Society 2024

Luque P.D., Koechler J., Balaji S.

Enciu M., Obertelli A., Doornenbal P., Heinz M., Miyagi T., Nowacki F., Ogata K., Poves A., Schwenk A., Yoshida K., Achouri N.L., Baba H., Browne F., Calvet D., Château F., et. al.

Dimastrogiovanni E., Fasiello M., Papageorgiou A.

Wang D., Mena O., Di Valentino E., Gariazzo S.

Alestas G., Delgado M., Ruiz I., Akrami Y., Montero M., Nesseris S.

Single-field models of accelerated expansion with nearly flat potentials, despite being able to provide observationally viable explanations for the early-time cosmic inflation and the late-time cosmic acceleration, are in strong tension with string theory evidence and the associated de Sitter swampland constraints. It has recently been argued that in an open universe, where the spatial curvature is negative (i.e., with Ωk>0), a new stable fixed point arises, which may lead to viable single-field-based accelerated expansion with an arbitrarily steep potential. Here, we show, through a dynamical systems analysis and a Bayesian statistical inference of cosmological parameters, that the additional cosmological solutions based on the new fixed point do not render steep-potential, single-field, accelerated expansion observationally viable. We mainly focus on quintessence models of dark energy, but we also argue that a similar conclusion can be drawn for cosmic inflation. Published by the American Physical Society 2024

Anisha, Domenech D., Englert C., Herrero M.J., Morales R.A.

The production of multiple Higgs bosons at the LHC and beyond is a strong test of the mechanism of electroweak symmetry breaking. Taking inspiration from recent experimental efforts to move toward limits on triple-Higgs production at the Large Hadron Collider, we consider generic bosonic deviations of HH and HHH production from the Standard Model in the guise of Higgs effective field theory (HEFT). Including one-loop radiative corrections within the HEFT and going up to O(p4) in the momentum expansion, we provide a detailed motivation of the parameter range that the LHC (and future hadron colliders) can explore, through accessing nonstandard coupling modifications and momentum dependencies that probe Higgs boson nonlinearities. In particular, we find that radiative corrections can enhance the sensitivity to Higgs self-coupling modifiers and HEFT-specific momentum dependencies can vastly increase triple-Higgs production, thus providing further motivation to consider these processes during the LHC’s high-luminosity phase. Published by the American Physical Society 2024

Enguita V., Gavela B., Grinstein B., Quílez P.

We compute the one-loop contribution to the θ¯ parameter of an faxionlike particle (ALP) with CP-odd derivative couplings. Its contribution to the neutron electric dipole moment is shown to be orders of magnitude larger than that stemming from the one-loop ALP contributions to the up- and down-quark electric and chromoelectric dipole moments. This strongly improves existing bounds on ALP-fermion CP-odd interactions and also sets limits on previously unconstrained couplings. The case of a general singlet scalar is analyzed as well. In addition, we explore how the bounds are modified in the presence of a Peccei-Quinn symmetry. Published by the American Physical Society 2024