ANTARES Collaboration(Albert, A. et al), Barrios-Marti, J., Coleiro, A., Colomer, M., Hernandez-Rey, J. J., Illuminati, G., et al. (2018). The search for neutrinos from TXS 0506+056 with the ANTARES telescope. Astrophys. J. Lett., 863(2), L30–6pp.
Abstract: The results of three different searches for neutrino candidates, associated with the IceCube-170922A event or from the direction of TXS 0506+056, by the ANTARES neutrino telescope, are presented. The first search refers to the online follow-up of the IceCube alert; the second is based on the standard time-integrated method employed by the Collaboration to search for point-like neutrino sources; the third uses information from the IceCube time-dependent analysis that reported bursting activity centered on 2014 December 13, as input for an ANTARES time-dependent analysis. The online follow-up and the time-dependent analysis yield no events related to the source. The time-integrated study performed over a period from 2007 to 2017 fits 1.03 signal events, which corresponds to a p-value of 3.4% (not considering trial factors). Only for two other astrophysical objects in our candidate list has a smaller p-value been found. When considering that 107 sources have been investigated, the post-trial p-value for TXS 0506+056 corresponds to 87%.
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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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ATLAS Collaboration(Aaboud, M. et al), Alvarez Piqueras, D., Aparisi Pozo, J. A., Bailey, A. J., Barranco Navarro, L., Cabrera Urban, S., et al. (2018). Search for Higgs boson pair production in the gamma gamma b(b)over-bar final state with 13 TeV pp collision data collected by the ATLAS experiment. J. High Energy Phys., 11(11), 040–44pp.
Abstract: A search is performed for resonant and non-resonant Higgs boson pair production in the final state. The data set used corresponds to an integrated luminosity of 36.1 fb(-1) of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. No significant excess relative to the Standard Model expectation is observed. The observed limit on the non-resonant Higgs boson pair cross-section is 0.73 pb at 95% confidence level. This observed limit is equivalent to 22 times the predicted Standard Model cross-section. The Higgs boson self-coupling (=(HHH)/SM) is constrained at 95% confidence level to -8.2 < < 13.2. For resonant Higgs boson pair production through , the limit is presented, using the narrow-width approximation, as a function of m(X) in the range 260 GeV < m(X) < 1000 GeV. The observed limits range from 1.1 pb to 0.12 pb over this mass range.
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ATLAS Collaboration(Aaboud, M. et al), Alvarez Piqueras, D., Aparisi Pozo, J. A., Bailey, A. J., Barranco Navarro, L., Cabrera Urban, S., et al. (2018). Prompt and non-prompt J/psi elliptic flow in Pb plus Pb collisions at root S-NN=5.02 TeV with the ATLAS detector. Eur. Phys. J. C, 78(9), 784–23pp.
Abstract: The elliptic flow of prompt and non-prompt J/psi was measured in the dimuon decay channel in Pb+Pb collisions at root S-NN = 5.02 TeV with an integrated luminosity of 0.42 nb(-1) with the ATLAS detector at the LHC. The prompt and non-prompt signals are separated using a two-dimensional simultaneous fit of the invariant mass and pseudo-proper decay time of the dimuon system from the J/psi decay. The measurement is performed in the kinematic range of dimuon transverse momentum and rapidity 9 < p(T) < 30 GeV, vertical bar y vertical bar < 2, and 0-60% collision centrality. The elliptic flow coefficient, v(2), is evaluated relative to the event plane and the results are presented as a function of transverse momentum, rapidity and centrality. It is found that prompt and non-prompt J/psi mesons have non-zero elliptic flow. Prompt J/psi v(2 )decreases as a function of p(T), while for non-prompt J/psi it is, with limited statistical significance, consistent with a flat behaviour over the studied kinematic region. There is no observed dependence on rapidity or centrality.
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Afonso, V. I., Olmo, G. J., Orazi, E., & Rubiera-Garcia, D. (2018). Mapping nonlinear gravity into General Relativity with nonlinear electrodynamics. Eur. Phys. J. C, 78(10), 866–11pp.
Abstract: We show that families of nonlinear gravity theories formulated in a metric-affine approach and coupled to a nonlinear theory of electrodynamics can be mapped into general relativity (GR) coupled to another nonlinear theory of electrodynamics. This allows to generate solutions of the former from those of the latter using purely algebraic transformations. This correspondence is explicitly illustrated with the Eddington-inspired Born-Infeld theory of gravity, for which we consider a family of nonlinear electrodynamics and show that, under the map, preserve their algebraic structure. For the particular case of Maxwell electrodynamics coupled to Born-Infeld gravity we find, via this correspondence, a Born-Infeld-type nonlinear electrodynamics on the GR side. Solving the spherically symmetric electrovacuum case for the latter, we show how the map provides directly the right solutions for the former. This procedure opens a new door to explore astrophysical and cosmological scenarios in nonlinear gravity theories by exploiting the full power of the analytical and numerical methods developed within the framework of GR.
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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). Search for CP violation in Lambda(0)(b)-> pK(- )and Lambda(0)(b) -> p pi(-) decays. Phys. Lett. B, 787, 124–133.
Abstract: A search for CP violation in Lambda(0)(b)-> pK(- )and Lambda(0)(b) -> p pi(-) decays is presented using a sample of pp collisions collected with the LHCb detector and corresponding to an integrated luminosity of 3.0fb(-1). The CP-violating asymmetries are measured to be A(CP)(pK- )( = -0.020 +/- 0.013 +/- 0.019 and A(CP)(p pi-) = -0.035 +/- 0.017 +/- 0.020, and their difference A(CP)(pK-) – A(CP)(p pi-) = 0.014 +/- 0.022 +/- 0.010, where the first uncertainties are statistical and the second systematic. These are the most precise measurements of such asymmetries to date.
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ATLAS Collaboration(Aaboud, M. et al), Alvarez Piqueras, D., Bailey, A. J., Barranco Navarro, L., Cabrera Urban, S., Castillo, F. L., et al. (2018). Search for lepton-flavor violation in different-flavor, high-mass final states in pp collisions at root s=13 TeV with the ATLAS detector. Phys. Rev. D, 98(9), 092008–34pp.
Abstract: A search is performed for a heavy particle decaying into different-flavor, dilepton pairs (e mu, e tau or μtau), using 36.1 fb(-1) of proton-proton collision data at root s = 13 TeV collected in 2015-2016 by the ATLAS detector at the Large Hadron Collider. No excesses over the Standard Model predictions are observed. Bayesian lower limits at the 95% credibility level are placed on the mass of a Z' boson, the mass of a supersymmetric tau-sneutrino, and on the threshold mass for quantum black-hole production. For the Z' and sneutrino models, upper cross-section limits are converted to upper limits on couplings, which are compared with similar limits from low-energy experiments and which are more stringent for the e tau and μtau modes.
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Wimmer, K. et al, Algora, A., & Rubio, B. (2018). Shape coexistence and isospin symmetry in A=70 nuclei: Spectroscopy of the T-z =-1 nucleus Kr-70. Phys. Lett. B, 785, 441–446.
Abstract: Excited states in the T-z = -1 nucleus Kr-70 have been populated using inelastic scattering of a radioactive Kr-70 beam as well as one- and two-neutron removal reactions from Kr-71,Kr-72 at intermediate beam energies. The level scheme of Kr-70 was constructed from the observed gamma-ray transitions and coincidences. Tentative spin and parity assignments were made based on comparison with the mirror nucleus Se-70. Asecond 2(+) state and a candidate for the corresponding 4(2)(+) state suggest shape coexistence in Kr-70.
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T2K Collaboration(Abe, K. et al), Antonova, M., Cervera-Villanueva, A., Fernandez, P., Izmaylov, A., & Novella, P. (2018). Search for CP Violation in Neutrino and Antineutrino Oscillations by the T2K Experiment with 2.2 x 10(21) Protons on Target. Phys. Rev. Lett., 121(17), 171802–9pp.
Abstract: The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of 14.7(7.6) x 10(20) protons on target in the neutrino (antineutrino) mode, 89 nu(e) candidates and seven anti-nu(e) candidates are observed, while 67.5 and 9.0 are expected for delta(CP) = 0 and normal mass ordering. The obtained 2 sigma confidence interval for the CP-violating phase, delta(CP), does not include the CP-conserving cases (delta(CP) = 0, pi). The best-fit values of other parameters are sin(2) theta(23) = 0.526(-0.036)(+0.032) and Delta m(32)(2) = 2.463(-0.070)(+0.071) x 10(-3) eV(2)/c(4).
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ATLAS Collaboration(Aaboud, M. et al), Alvarez Piqueras, D., Aparisi Pozo, J. A., Bailey, A. J., Barranco Navarro, L., Cabrera Urban, S., et al. (2018). Search for charged Higgs bosons decaying via H-+/- -> tau(+/-)nu(tau) in the tau plus jets and tau plus lepton final states with 36 fb(-1) of pp collision data recorded at root s=13 TeV with the ATLAS experiment. J. High Energy Phys., 09(9), 139–48pp.
Abstract: Charged Higgs bosons produced either in top-quark decays or in association with a top-quark, subsequently decaying via H-+/-! -> tau(+/-)nu(tau), are searched for in 36.1 fb(-1) of proton-proton collision data at root s = 13TeV recorded with the ATLAS detector. Depending on whether the top-quark produced together with H-+/- decays hadronically or leptonically, the search targets tau+jets and tau+lepton fi nal states, in both cases with a hadronically decaying tau-lepton. No evidence of a charged Higgs boson is found. For the mass range of m(H)+/- = 90-2000 GeV, upper limits at the 95% con fi dence level are set on the production cross-section of the charged Higgs boson times the branching fraction B (H-+/-->tau(+/-)nu(tau)) in the range 4.2-0.0025 pb. In the mass range 90{160 GeV, assuming the Standard Model cross-section for tit production, this corresponds to upper limits between 0.25% and 0.031% for the branching fraction B (t -> bH(+/-)) x B (H-+/- -> tau(+/-)nu(tau)).
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