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Meloni, D., Morisi, S., & Peinado, E. (2012). Predicting leptonic CP violation in the light of the Daya Bay result on theta(13). Eur. Phys. J. C, 72(9), 2160–4pp.
Abstract: In the light of the recent Daya Bay result theta(DB)(13) = 8.8 degrees +/- 0.8 degrees, we reconsider the model presented in Meloni et al. (J. Phys. G 38: 015003, 2011), showing that, when all neutrino oscillation parameters are taken at their best fit values of Schwetz et al. (New J. Phys. 10: 113011, 2008) and where theta(13) = theta(DB)(13), the predicted values of the CP phase are delta approximate to pi/4.
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Staub, F., Athron, P., Basso, L., Goodsell, M. D., Harries, D., Krauss, M. E., et al. (2016). Precision tools and models to narrow in on the 750 GeV diphoton resonance. Eur. Phys. J. C, 76(9), 516–57pp.
Abstract: The hints for a new resonance at 750 GeV from ATLAS and CMS have triggered a significant amount of attention. Since the simplest extensions of the standard model cannot accommodate the observation, many alternatives have been considered to explain the excess. Here we focus on several proposed renormalisable weakly-coupled models and revisit results given in the literature. We point out that physically important subtleties are often missed or neglected. To facilitate the study of the excess we have created a collection of 40 model files, selected from recent literature, for the Mathematica package SARAH. With SARAH one can generate files to perform numerical studies using the tailor-made spectrum generators FlexibleSUSY and SPheno. These have been extended to automatically include crucial higher order corrections to the diphoton and digluon decay rates for both CP-even and CP-odd scalars. Additionally, we have extended the UFO and CalcHep interfaces of SARAH, to pass the precise information about the effective vertices from the spectrum generator to a Monte-Carlo tool. Finally, as an example to demonstrate the power of the entire setup, we present a new supersymmetric model that accommodates the diphoton excess, explicitly demonstrating how a large width can be obtained. We explicitly show several steps in detail to elucidate the use of these public tools in the precision study of this model.
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ATLAS Collaboration(Aaboud, M. et al), Alvarez Piqueras, D., Barranco Navarro, L., Cabrera Urban, S., Castillo Gimenez, V., Cerda Alberich, L., et al. (2017). Precision measurement and interpretation of inclusive W+, W- and Z/gamma* production cross sections with the ATLAS detector. Eur. Phys. J. C, 77(6), 367–62pp.
Abstract: High-precision measurements by the ATLAS Collaboration are presented of inclusive W+ -> l(+) nu, W- -> l(-) (nu) over bar and Z/gamma* -> ll (l = e, mu) Drell-Yan production cross sections at the LHC. The data were collected in proton-proton collisions at root s = 7 TeV with an integrated luminosity of 4.6 fb(-1). Differential W+ and W- cross sections are measured in a lepton pseudorapidity range vertical bar eta(l)vertical bar < 2.5. Differential Z/gamma* cross sections are measured as a function of the absolute dilepton rapidity, for vertical bar y(ll)vertical bar < 3.6, for three intervals of dilepton mass, m(ll), extending from 46 to 150 GeV. The integrated and differential electron- and muon-channel cross sections are combined and compared to theoretical predictions using recent sets of parton distribution functions. The data, together with the final inclusive e(+/-) p scattering cross-section data from H1 and ZEUS, are interpreted in a next-to-next-to-leading-order QCD analysis, and a new set of parton distribution functions, ATLAS-epWZ16, is obtained. The ratio of strange-to-light sea-quark densities in the proton is determined more accurately than in previous determinations based on collider data only, and is established to be close to unity in the sensitivity range of the data. A new measurement of the CKM matrix element vertical bar V-cs vertical bar is also provided.
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Sandner, S., Escudero, M., & Witte, S. J. (2023). Precision CMB constraints on eV-scale bosons coupled to neutrinos. Eur. Phys. J. C, 83(8), 709–12pp.
Abstract: The cosmic microwave background (CMB) has proven to be an invaluable tool for studying the properties and interactions of neutrinos, providing insight not only into the sum of neutrino masses but also the free streaming nature of neutrinos prior to recombination. The CMB is a particularly powerful probe of new eV-scale bosons interacting with neutrinos, as these particles can thermalizewith neutrinos via the inverse decay process, v (v) over bar -> X, and suppress neutrino free streaming near recombination – even for couplings as small as lambda(v) similar to O(10(-13)). Here, we revisit CMB constraints on such bosons, improving upon a number of approximations previously adopted in the literature and generalizing the constraints to a broader class of models. This includes scenarios in which the boson is either spin-0 or spin-1, the number of interacting neutrinos is either N-int = 1, 2 or 3, and the case in which a primordial abundance of the species is present. We apply these bounds to well-motivatedmodels, such as the singlet majoron model or a light U(1) L-mu- L-t gauge boson, and find that they represent the leading constraints for masses m(X) similar to 1 eV. Finally, we revisit the extent to which neutrinophilic bosons can ameliorate the Hubble tension, and find that recent improvements in the understanding of how such bosons damp neutrino free streaming reduces the previously found success of this proposal.
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Bordes, J., Chan, H. M., & Tsun, T. S. (2010). Possible anomalies in Higgs decay: charm-suppression and flavour-violation. Eur. Phys. J. C, 65(3-4), 537–542.
Abstract: It is suggested that the Higgs boson may have a branching ratio into the c (c) over bar c mode suppressed by several orders of magnitude compared with conventional predictions and in addition some small but detectable flavour-violating modes such as b (s) over bar and tau(mu) over bar. The suggestion is based on a scheme proposed and tested earlier for explaining the mixing pattern and mass hierarchy of fermions in terms of a rotating mass matrix. If confirmed, the effects would cast new light on the geometric origin of fermion generations and of the Higgs field itself.
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