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ATLAS Collaboration(Aad, G. et al), Alvarez Piqueras, D., Aparisi Pozo, J. A., Bailey, A. J., Cabrera Urban, S., Castillo, F. L., et al. (2020). Search for squarks and gluinos in final states with same-sign leptons and jets using 139 fb(-1) of data collected with the ATLAS detector. J. High Energy Phys., 06(6), 046–44pp.
Abstract: A search for supersymmetric partners of gluons and quarks is presented, involving signatures with jets and either two isolated leptons (electrons or muons) with the same electric charge, or at least three isolated leptons. A data sample of proton-proton collisions at root s = 13 TeV recorded with the ATLAS detector at the Large Hadron Collider between 2015 and 2018, corresponding to a total integrated luminosity of 139 fb(-1), is used for the search. No significant excess over the Standard Model expectation is observed. The results are interpreted in simplified supersymmetric models featuring both R-parity conservation and R-parity violation, raising the exclusion limits beyond those of previous ATLAS searches to 1600 GeV for gluino masses and 750 GeV for bottom and top squark masses in these scenarios.
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LHCb Collaboration(Aaij, R. et al), Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., & Ruiz Vidal, J. (2022). Study of charmonium and charmonium-like contributions in B+ -> J/psi eta K+ decays. J. High Energy Phys., 04(4), 046–29pp.
Abstract: A study of B+ -> J/psi eta K+ decays, followed by J/psi -> mu(+)mu(-) and eta -> gamma gamma, is performed using a dataset collected with the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb(-1). The J/psi eta mass spectrum is investigated for contributions from charmonia and charmonium-like states. Evidence is found for the B+ -> (psi(2)(3823) -> J/psi eta)K+ and B+ -> (psi(4040) -> J/psi eta)K+ decays with significance of 3.4 and 4.7 standard deviations, respectively. This constitutes the first evidence for the psi(2)(3823) -> J/psi eta decay.
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Bayar, M., Martinez Torres, A., Khemchandani, K. P., Molina, R., & Oset, E. (2023). Exotic states with triple charm. Eur. Phys. J. C, 83(1), 46–9pp.
Abstract: In this work we investigate the possibility of the formation of states from the dynamics involved in the D* D* D* system by considering that two D*'s generate a JP = 1+ bound state, with isospin 0, which has been predicted in an earlier theoretical work. We solve the Faddeev equations for this system within the fixed center approximation and find the existence of J(P) = 0(-), 1(-) and 2(-) states with charm 3, isospin 1/2, masses similar to 6000 MeV, which are manifestly exotic hadrons, i.e., with a multiquark inner structure.
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Gariazzo, S., Martinez-Mirave, P., Mena, O., Pastor, S., & Tortola, M. (2023). Non-unitary three-neutrino mixing in the early Universe. J. Cosmol. Astropart. Phys., 03(3), 046–18pp.
Abstract: Deviations from unitarity in the three-neutrino mixing canonical picture are expected in many physics scenarios beyond the Standard Model. The mixing of new heavy neutral leptons with the three light neutrinos would in principle modify the strength and flavour structure of charged-current and neutral-current interactions with matter. Non-unitarity effects would therefore have an impact on the neutrino decoupling processes in the early Universe and on the value of the effective number of neutrinos, Neff. We calculate the cosmological energy density in the form of radiation with a non-unitary neutrino mixing matrix, addressing the possible interplay between parameters. Highly accurate measurements of Neff from forthcoming cosmological observations can provide independent and complementary limits on the departures from unitarity. For completeness, we relate the scenario of small deviations from unitarity to non-standard neutrino interactions and compare the forecasted constraints to other existing limits in the literature.
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Carcamo Hernandez, A. E., Vishnudath, K. N., & Valle, J. W. F. (2023). Linear seesaw mechanism from dark sector. J. High Energy Phys., 09(9), 046–18pp.
Abstract: We propose a minimal model where a dark sector seeds neutrino mass generation radiatively within the linear seesaw mechanism. Neutrino masses are calculable, since treelevel contributions are forbidden by symmetry. They arise from spontaneous lepton number violation by a small Higgs triplet vacuum expectation value. Lepton flavour violating processes e.g. μ-> e gamma can be sizeable, despite the tiny neutrino masses. We comment also on dark-matter and collider implications.
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Gomez-Vargas, G. A., Lopez-Fogliani, D. E., Muñoz, C., Perez, A. D., & Ruiz de Austri, R. (2017). Search for sharp and smooth spectral signatures of μnu SSM gravitino dark matter with Fermi- LAT. J. Cosmol. Astropart. Phys., 03(3), 047–23pp.
Abstract: The μnu SSM solves the μproblem of supersymmetric models and reproduces neutrino data, simply using couplings with right-handed neutrinos nu's. Given that these couplings break explicitly R parity, the gravitino is a natural candidate for decaying dark matter in the μnu SSM. In this work we carry out a complete analysis of the detection of μnu SSM gravitino dark matter through gamma-ray observations. In addition to the two-body decay producing a sharp line, we include in the analysis the three-body decays producing a smooth spectral signature. We perform first a deep exploration of the low-energy parameter space of the μnu SSM taking into account that neutrino data must be reproduced. Then, we compare the gamma-ray fluxes predicted by the model with Fermi-LAT observations. In particular, with the 95% CL upper limits on the total diffuse extragalactic gamma-ray background using 50 months of data, together with the upper limits on line emission from an updated analysis using 69.9 months of data. For standard values of bino and wino masses, gravitinos with masses larger than about 4 GeV, or lifetimes smaller than about 10(28) s, produce too large fluxes and are excluded as dark matter candidates. However, when limiting scenarios with large and close values of the gaugino masses are considered, the constraints turn out to be less stringent, excluding masses larger than 17 GeV and lifetimes smaller than 4 x 10(25) s.
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Arguelles, C. A., Palomares-Ruiz, S., Schneider, A., Wille, L., & Yuan, T. L. (2018). Unified atmospheric neutrino passing fractions for large-scale neutrino telescopes. J. Cosmol. Astropart. Phys., 07(7), 047–41pp.
Abstract: The atmospheric neutrino passing fraction, or self-veto, is defined as the probability for an atmospheric neutrino not to be accompanied by a detectable muon from the same cosmic-ray air shower. Building upon previous work, we propose a redefinition of the passing fractions by unifying the treatment for muon and electron neutrinos. Several approximations have also been removed. This enables performing detailed estimations of the uncertainties in the passing fractions from several inputs: muon losses, cosmic-ray spectrum, hadronic-interaction models and atmosphere-density profiles. We also study the passing fractions under variations of the detector configuration: depth, surrounding medium and muon veto trigger probability. The calculation exhibits excellent agreement with passing fractions obtained from Monte Carlo simulations. Finally, we provide a general software framework to implement this veto technique for all large-scale neutrino observatories.
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de Medeiros Varzielas, I., Lopez-Ibañez, M. L., Melis, A., & Vives, O. (2018). Controlled flavor violation in the MSSM from a unified Delta(27) flavor symmetry. J. High Energy Phys., 09(9), 047–22pp.
Abstract: We study the phenomenology of a unified supersymmetric theory with a flavor symmetry Delta(27). The model accommodates quark and lepton masses, mixing angles and CP phases. In this model, the Dirac and Majorana mass matrices have a unified texture zero structure in the (1, 1) entry that leads to the Gatto-Sartori-Tonin relation between the Cabibbo angle and ratios of the masses in the quark sectors, and to a natural departure from zero of the theta 13(l) angle in the lepton sector. We derive the flavor structures of the trilinears and soft mass matrices, and show their general non-universality. This causes large flavor violating effects. As a consequence, the parameter space for this model is constrained, allowing it to be (dis)proven by flavor violation searches in the next decade. Although the results are model specific, we compare them to previous studies to show similar flavor effects (and associated constraints) are expected in general in supersymmetric flavor models, and may be used to distinguish them.
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Testov, D. et al, & Gadea, A. (2019). The 4pi highly-efficient light-charged-particle detector EUCLIDES, installed at the GALILEO array for in-beam gamma-ray spectroscopy. Eur. Phys. J. A, 55(4), 47–8pp.
Abstract: .In a fusion-evaporation reaction, nuclei are produced by evaporating light-charged particles and neutrons from the compound nucleus. Typically, a nucleus of interest is produced as a result of a part of the total cross-section and, in order to guarantee a good channel discrimination, a particle detector, like the EUCLIDES 4 Si-ball array, is necessary. EUCLIDES has been quoted in more than a hundred publications resulting from many experiments performed in combination with the EUROBALL and GASP -ray spectrometers. The present paper reports on the upgraded version of EUCLIDES, that is presently coupled to the new GALILEO -ray spectrometer, installed at the Laboratori Nazionali di Legnaro, INFN. The design, characteristics and performance of the EUCLIDES array are presented and discussed.
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Lopez-Ibañez, M. L., Melis, A., Meloni, D., & Vives, O. (2019). Lepton flavor violation and neutrino masses from A(5) and CP in the non-universal MSSM. J. High Energy Phys., 06(6), 047–34pp.
Abstract: We analyze the phenomenological consequences of embedding a flavor symmetry based on the groups A(5) and CP in a supersymmetric framework. We concentrate on the leptonic sector, where two different residual symmetries are assumed to be conserved at leading order for charged and neutral leptons. All possible realizations to generate neutrino masses at tree level are investigated. Sizable flavor violating effects in the charged lepton sector are unavoidable due to the non-universality of soft-breaking terms determined by the symmetry. We derive testable predictions for the neutrino spectrum, lepton mixing and flavor changing processes with non-trivial relations among observables.
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