Wilkinson, C., & Garcia Soto, A. (2024). Low-ν method with LHC neutrinos. Phys. Rev. D, 109(3), 033010–19pp.
Abstract: The Forward Physics Facility (FPF) plans to use neutrinos produced at the Large Hadron Collider to make a variety of measurements at previously unexplored TeV energies. Its primary goals include precision measurements of the neutrino cross section and using the measured neutrino flux both to uncover information about far-forward hadron production and to search for various beyond standard model scenarios. However, these goals have the potential to conflict: Extracting information about the flux or cross section relies upon an assumption about the other. In this paper, we demonstrate that the FPF can use the low-nu method-a technique for constraining the flux shape by isolating neutrino interactions with low energy transfer to the nucleus-to break this degeneracy. We show that the low-nu method is effective for extracting the nu μflux shape, in a model-independent way. We discuss its application for extracting the nu over bar μflux shape but find that this is significantly more model dependent. Finally, we explore the precision to which the nu μflux shape could be constrained at the FPF for a variety of proposed detector options. We find that the precision would be sufficient to discriminate between various realistic flux models.
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ATLAS Collaboration(Aad, G. et al), Aparisi Pozo, J. A., Bailey, A. J., Cabrera Urban, S., Castillo, F. L., Castillo Gimenez, V., et al. (2024). Search for quantum black hole production in lepton plus jet final states using proton-proton collisions at √s=13 TeV with the ATLAS detector. Phys. Rev. D, 109(3), 032010–28pp.
Abstract: A search for quantum black holes in electron + jet and muon + jet invariant mass spectra is performed with 140 fb(-1) of data collected by the ATLAS detector in proton-proton collisions at root s = 13 TeV at the Large Hadron Collider. The observed invariant mass spectrum of lepton + jet pairs is consistent with Standard Model expectations. Upper limits are set at 95% confidence level on the production cross section times branching fractions for quantum black holes decaying into a lepton and a quark in a search region with invariant mass above 2.0 TeV. The resulting quantum black hole lower mass threshold limit is 9.2 TeV in the Arkani-Hamed-Dimopoulos-Dvali model, and 6.8 TeV in the Randall-Sundrum model.
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Fajfer, S., Solomonidi, E., & Vale Silva, L. (2024). S-wave contribution to rare D0 → π+ π- l+ l- decays in the standard model and sensitivity to new physics. Phys. Rev. D, 109(3), 036027–24pp.
Abstract: Physics of the up-type flavor offers unique possibilities of testing the standard model (SM) compared to the down-type flavor sector. Here, we discuss SM and new physics (NP) contributions to the rare charmmeson decay D0 -> x+x- l+l-. In particular, we discuss the effect of including the lightest scalar isoscalar resonance in the SM picture, namely, the f0(500), which manifests in a big portion of the allowed phase space. Other than showing in the total branching ratio at an observable level of about 20%, the f0(500) resonance manifests as interference terms with the vector resonances, such as at high invariant mass of the leptonic pair in distinct angular observables. Recent data from LHCb optimize the sensitivity to P-wave contributions that we analyze in view of the inclusion of vector resonances. We propose the measurement of alternative observables that are sensitive to the S-wave and are straightforward to implement experimentally. This leads to a new set of null observables that vanish in the SM due to its gauge and flavor structures. Finally, we study observables that depend on the SM interference with generic NP contributions from semileptonic four-fermion operators in the presence of the S-wave.
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Alexandre, J., Mavromatos, N. E., Mitsou, V. A., & Musumeci, E. (2024). Resummation schemes for high-electric-charge objects leading to improved experimental mass limits. Phys. Rev. D, 109(3), 036026–20pp.
Abstract: High-electric-charge compact objects (HECOs) appear in several theoretical particle physics models beyond the Standard Model, and are actively searched for in current colliders, such as the Large Hadron Collider at CERN. In such searches, mass bounds of these objects have been placed, using Drell-Yan and photon-fusion processes at tree level so far. However, such mass-bound estimates are not reliable, given that, as a result of the large values of the electric charge of the HECO, perturbative quantum electrodynamics calculations break down. In this work, we perform a Dyson-Schwinger resummation scheme (as opposed to lattice strong-coupling approach), which makes the computation of the pertinent HECO-production cross sections reliable, thus allowing us to extract improved mass bounds for such objects from ATLAS and MoEDAL searches.
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Karan, A., Miralles, V., & Pich, A. (2024). Updated global fit of the aligned two-Higgs-doublet model with heavy scalars. Phys. Rev. D, 109(3), 035012–29pp.
Abstract: An updated global fit on the parameter-space of the aligned two-Higgs-doublet model is performed with the help of the open-source package HEPfit, assuming the Standard-Model Higgs to be the lightest scalar. No new sources of CP violation, other than the phase in the Cabibbo-Kobayashi-Maskawa matrix of the Standard Model, are considered. A similar global fit was previously performed by O. Eberhardt et al. [Global fits in the aligned two-Higgs-doublet model, J. High Energy Phys. 05 (2021) 005] with a slightly different set of parameters. Our updated fit incorporates improved analyses of the theoretical constraints required for the perturbative unitarity and boundedness of the scalar potential from below, additional flavor observables and updated data on direct searches for heavy scalars at the LHC, Higgs signal strengths, and electroweak precision observables. Although not included in the main fit, the implications of the CDF measurement of the W +/- mass are also discussed.
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