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Di Valentino, E., Gariazzo, S., Giunti, C., Mena, O., Pan, S., & Yang, W. Q. (2022). Minimal dark energy: Key to sterile neutrino and Hubble constant tensions? Phys. Rev. D, 105(10), 103511–15pp.
Abstract: Minimal dark energy models, described by the same number of free parameters of the standard cosmological model with cold dark matter plus a cosmological constant to parametrize the dark energy component, constitute very appealing scenarios which may solve long-standing, pending tensions. On the one hand, they alleviate significantly the tension between cosmological observations and the presence of one sterile neutrino motivated by the short-baseline anomalies: we obtain a 95% CL cosmological bound on the mass of a fully thermalized fourth sterile neutrino (N-eff = 4) equal to m(s) < 0.65(1.3) eV within the Phenomenologically Emergent Dark Energy (PEDE) and Vacuum Metamorphosis (VM) scenarios under consideration. Interestingly, these limits are in agreement with the observations at short-baseline experiments, and the PEDE scenario is favored with respect to the Lambda CDM case when the full data combination is considered. On the other hand, the Hubble tension is satisfactorily solved in almost all the minimal dark energy schemes explored here. These phenomenological scenarios may therefore shed light on differences arising from near and far Universe probes, and also on discrepancies between cosmological and laboratory sterile neutrino searches.
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Mandal, S., Miranda, O. G., Sanchez Garcia, G., Valle, J. W. F., & Xu, X. J. (2022). Toward deconstructing the simplest seesaw mechanism. Phys. Rev. D, 105(9), 095020–32pp.
Abstract: The triplet or type-II seesaw mechanism is the simplest way to endow neutrinos with mass in the Standard Model (SM). Here we review its associated theory and phenomenology, including restrictions from S, T, U parameters, neutrino experiments, charged lepton flavor violation as well as collider searches. We also examine restrictions coming from requiring consistency of electroweak symmetry breaking, i.e., perturbative unitarity and stability of the vacuum. Finally, we discuss novel effects associated to the scalar mediator of neutrino mass generation namely, (i) rare processes, e.g., l(alpha)-> l(beta)gamma decays, at the intensity frontier, and also (ii) four-lepton signatures in colliders at the high-energy frontier. These can be used to probe neutrino properties in an important way, providing a test of the absolute neutrino mass and mass ordering, as well as of the atmospheric octant. They may also provide the first evidence for charged lepton flavor violation in nature. In contrast, neutrino nonstandard interaction strengths are found to lie below current detectability.
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Dai, L. R., Molina, R., & Oset, E. (2022). Looking for the exotic X-0(2866) and its J(P)=1(+) partner in the (B)over-bar(0) -> D-(*) + K- K-(*)0 reactions. Phys. Rev. D, 105(9), 096022–7pp.
Abstract: We propose two reactions, (B) over bar (0) -> (KD+K-)-D-0 and (B) over bar (0) -> K*D-0*K-+(-), which have been already measured at Belle, to look into the J(P) = 0(+), X-0(2866) state and a 1(+) partner of molecular D*(K) over bar* nature by looking at the D+K- and D*K-+(-) invariant mass distributions, respectively. Very clear peaks over the background are predicted and the branching ratios for the production of these states are evaluated to facilitate the task of determining the needed statistics for their observation. We conclude that with the upgrade of Belle II clear peaks should be seen in both reactions for the two resonances discussed.
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ATLAS Collaboration(Aad, G. et al), Aparisi Pozo, J. A., Bailey, A. J., Cabrera Urban, S., Cardillo, F., Castillo Gimenez, V., et al. (2022). Search for resonant pair production of Higgs bosons in the b(b)over-barb(b)over-bar final state using pp collisions at root s=13 TeV with the ATLAS detector. Phys. Rev. D, 105(9), 092002–36pp.
Abstract: A search for resonant Higgs boson pair production in the b (b) over barb (b) over bar final state is presented. The analysis uses 126 fb(-1)- 139 fb(-1) of pp collision data at root s = 13 TeV collected with the ATLAS detector at the Large Hadron Collider. The analysis is divided into two channels, targeting Higgs boson decays which are reconstructed as pairs of small-radius jets or as individual large-radius jets. Spin-0 and spin2 benchmark signal models are considered, both of which correspond to resonant HH production via gluon-gluon fusion. The data are consistent with Standard Model predictions. Upper limits are set on the production cross section times branching ratio to Higgs boson pairs of a new resonance in the mass range from 251 GeV to 5 TeV.
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ATLAS Collaboration(Aad, G. et al), Amos, K. R., Aparisi Pozo, J. A., Bailey, A. J., Cabrera Urban, S., Cardillo, F., et al. (2022). Constraints on Higgs boson production with large transverse momentum using H -> b(b)over-bar decays in the ATLAS detector. Phys. Rev. D, 105(9), 092003–37pp.
Abstract: This paper reports constraints on Higgs boson production with transverse momentum above 1 TeV. The analyzed data from proton-proton collisions at a center-of-mass energy of 13 TeV were recorded with the ATLAS detector at the Large Hadron Collider from 2015 to 2018 and correspond to an integrated luminosity of 136 fb(-1.) Higgs bosons decaying into b (b) over bar are reconstructed as single large-radius jets recoiling against a hadronic system and are identified by the experimental signature of two b-hadron decays. The experimental techniques are validated in the same kinematic regime using the Z -> b (b) over bar process. The 95% confidence-level upper limit on the cross section for Higgs boson production with transverse momentum above 450 GeV is 115 fb, and above 1 TeV it is 9.6 fb. The Standard Model cross section predictions for a Higgs boson with a mass of 125 GeV in the same kinematic regions are 18.4 fb and 0.13 fb, respectively.
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