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Bordes, J., Chan, H. M., & Tsun, S. S. (2018). A closer study of the framed standard model yielding testable new physics plus a hidden sector with dark matter candidates. Int. J. Mod. Phys. A, 33(33), 1850195–75pp.
Abstract: This closer study of the FSM (1) retains the earlier results of Ref. 1 in offering explanation for the existence of three fermion generations, as well as the hierarchical mass and mixing patterns of leptons and quarks; (II) predicts a vector boson G with mass of order TeV which mixes gamma with and Z of the standard model. The subsequent deviations from the standard mixing scheme are calculable in terms of the G mass. While these deviations for (i) mz – mw, (ii) Gamma(Z -> l (+)l( -)), and (iii) F(Z -> hadrons) are all within present experimental errors so long as mG > 1 TeV, they should soon be detectable if the G mass is not too much bigger; (III) suggests that in parallel to the standard sector familiar to us, there is another where the roles of flavour and colour are interchanged. Though quite as copiously populated and as vibrant in self-interactions as our own, it communicates but little with the standard sector except via mixing through a couple of known portals, one of which is the gamma – Z – G complex noted in (II), and the other is a scalar complex which includes the standard model Higgs. As a result, the new sectors paper. appears hidden to us as we appear hidden to them, and so its lowest members with masses of order 10 MeV, being electrically neutral and seemingly stable, but abundant, may make eligible candidates as constituents of dark matter. A more detailed summary of these results together with some remarks on the model's special theoretical features can be found in the last section of this paper.
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Escudero, M., Lopez-Honorez, L., Mena, O., Palomares-Ruiz, S., & Villanueva-Domingo, P. (2018). A fresh look into the interacting dark matter scenario. J. Cosmol. Astropart. Phys., 06(6), 007–35pp.
Abstract: The elastic scattering between dark matter particles and radiation represents an attractive possibility to solve a number of discrepancies between observations and standard cold dark matter predictions, as the induced collisional damping would imply a suppression of small-scale structures. We consider this scenario and confront it with measurements of the ionization history of the Universe at several redshifts and with recent estimates of the counts of Milky Way satellite galaxies. We derive a conservative upper bound on the dark matter photon elastic scattering cross section of sigma gamma DM < 8 x 10(-10) sigma(T) (m(DM)/GeV) at 95% CL, about one order of magnitude tighter than previous constraints from satellite number counts. Due to the strong degeneracies with astrophysical parameters, the bound on the dark matter-photon scattering cross section derived here is driven by the estimate of the number of Milky Way satellite galaxies. Finally, we also argue that future 21 cm probes could help in disentangling among possible non-cold dark matter candidates, such as interacting and warm dark matter scenarios. Let us emphasize that bounds of similar magnitude to the ones obtained here could be also derived for models with dark matter-neutrino interactions and would be as constraining as the tightest limits on such scenarios.
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2018). A measurement of the CP asymmetry difference between Lambda(+)(C) -> pK(-)K(+) and p pi(-)pi(+) decays. J. High Energy Phys., 03(3), 182–21pp.
Abstract: The difference between the CP asymmetries in the decays Lambda(+)(C) -> pK(-)K(+) and Lambda(+)(C) -> p pi(-)pi(+) is presented. Proton-proton collision data taken at centre-of-mass energies of 7 and 8 TeV collected by the LHCb detector in 2011 and 2012 are used, corresponding to an integrated luminosity of 3 fb(-1). The Lambda(+)(C) candidates are reconstructed as part of the Lambda(0)(b) -> Lambda(+)(c)mu X- decay chain. In order to maximize the cancellation of production and detection asymmetries in the difference, the final-state kinematic distributions of the two samples are aligned by applying phase-space-dependent weights to the Lambda(+)(C) -> pK(-)K(+) sample. This alters the definition of the integrated CP asymmetry to A(CP)(wgt)(p pi(-)pi(+)). Both samples are corrected for reconstruction and selection efficiencies across the five-dimensional Lambda(+)(C) decay phase space. The difference in CP asymmetries is found to be Delta A(CP)(wgt) = A(CP)(pK(-)K(+)) – A(CP)(wgt)(p pi(-)pi(+)) = (0.30 +/- 0.91 +/- 0.61) %, where the first uncertainty is statistical and the second is systematic.
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Rinaldi, M., Scopetta, S., Traini, M., & Vento, V. (2018). A model calculation of double parton distribution functions of the pion. Eur. Phys. J. C, 78(9), 781–9pp.
Abstract: Two-parton correlations in the pion are investigated in terms of double parton distribution functions. A Poincare covariant light-front framework has been adopted. As non perturbative input, the pion wave function obtained within the so-called soft-wall AdS/QCD model has been used. Results show how novel dynamical information on the structure of the pion, not accessible through one-body quantities, are encoded in double parton distribution functions.
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Keivani, A., Murase, K., Petropoulou, M., Fox, D. B., Cenko, S. B., Chaty, S., et al. (2018). A Multimessenger Picture of the Flaring Blazar TXS 0506+056: Implications for High-energy Neutrino Emission and Cosmic-Ray Acceleration. Astrophys. J., 864(1), 84–16pp.
Abstract: Detection of the IceCube-170922A neutrino coincident with the flaring blazar TXS 0506+056, the first and only similar to 3 sigma high-energy neutrino source association to date, offers a potential breakthrough in our understanding of high-energy cosmic particles and blazar physics. We present a comprehensive analysis of TXS. 0506+056 during its flaring state, using newly collected Swift, NuSTAR, and X-shooter data with Fermi observations and numerical models to constrain the blazar's particle acceleration processes and multimessenger (electromagnetic (EM) and high-energy neutrino) emissions. Accounting properly for EM cascades in the emission region, we find a physically consistent picture only within a hybrid leptonic scenario, with gamma-rays produced by external inverse-Compton processes and high-energy neutrinos via a radiatively subdominant hadronic component. We derive robust constraints on the blazar's neutrino and cosmic-ray emissions and demonstrate that, because of cascade effects, the 0.1-100 keV emissions of TXS. 0506+056 serve as a better probe of its hadronic acceleration and highenergy neutrino production processes than its GeV-TeV emissions. If the IceCube neutrino association holds, physical conditions in the TXS. 0506+056 jet must be close to optimal for high-energy neutrino production, and are not favorable for ultrahigh-energy cosmic-ray acceleration. Alternatively, the challenges we identify in generating a significant rate of IceCube neutrino detections from TXS. 0506+056 may disfavor single-zone models, in which.-rays and high-energy neutrinos are produced in a single emission region. In concert with continued operations of the high-energy neutrino observatories, we advocate regular X-ray monitoring of TXS. 0506+056 and other blazars in order to test single-zone blazar emission models, clarify the nature and extent of their hadronic acceleration processes, and carry out the most sensitive possible search for additional multimessenger sources.
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