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n_TOF Collaboration(Diakaki, M. et al), Domingo-Pardo, C., & Tain, J. L. (2016). Neutron-induced fission cross section of Np-237 in the keV to MeV range at the CERN n_TOF facility. Phys. Rev. C, 93(3), 034614–12pp.
Abstract: The neutron-induced fission cross section of Np-237 was experimentally determined at the high-resolution and high-intensity facility n_TOF, at CERN, in the energy range 100 keV to 9 MeV, using the U-235(n, f) and U-238(n, f) cross section standards below and above 2 MeV, respectively. A fast ionization chamber was used in order to detect the fission fragments from the reactions and the targets were characterized as far as their mass and homogeneity are concerned by means of a spectroscopy and Rutherford backscattering spectroscopy respectively. Theoretical calculations within the Hauser-Feshbach formalism have been performed, employing the EMPIRE code, and the model parameters were tuned in order to successfully reproduce the experimental fission cross-sectional data and simultaneously all the competing reaction channels.
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Fabbri, A., Balbinot, R., & Anderson, P. R. (2016). Scattering coefficients and gray-body factor for 1D BEC acoustic black holes: Exact results. Phys. Rev. D, 93(6), 064046–6pp.
Abstract: A complete set of exact analytic solutions to the mode equation is found in the region exterior to the acoustic horizon for a class of 1D Bose-Einstein condensate acoustic black holes. From these, analytic expressions for the scattering coefficients and gray-body factor are obtained. The results are used to verify previous predictions regarding the behaviors of the scattering coefficients and gray-body factor in the low-frequency limit.
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Sun, Z. F., Bayar, M., Fernandez-Soler, P., & Oset, E. (2016). Ds0*(2317)(+) in the decay of Bc into J/Psi DK. Phys. Rev. D, 93(5), 054028–9pp.
Abstract: In this paper we study the relationship between the D-s0*(2317)(+) resonance and the decay of the B-c meson into J/Psi DK. In this process, the B-c meson decays first into J/Psi and the quark pair c (s) over bar, and then the quark pair hadronizes into DK or D-s eta components, which undergo final state interaction. This final state interaction, generating the D-s0*(2317)(+) resonance, is described by the chiral unitary approach. With the parameters which allow us to match the pole position of the D-s0*(2317)(+), we obtain the DK invariant mass distribution of the decay B-c -> J/Psi DK, and also the rate for B-c -> J/Psi D-s0*(2317). The ratio of these two magnitudes is then predicted.
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ATLAS Collaboration(Aad, G. et al), Alvarez Piqueras, D., Barranco Navarro, L., Cabrera Urban, S., Castillo Gimenez, V., Cerda Alberich, L., et al. (2016). Search for new phenomena with photon plus jet events in proton-proton collisions at TeV with the ATLAS detector. J. High Energy Phys., 03(3), 041–37pp.
Abstract: A search is performed for the production of high-mass resonances decaying into a photon and a jet in 3.2 fb(-1) of proton-proton collisions at a centre-of-mass energy of TeV collected by the ATLAS detector at the Large Hadron Collider. Selected events have an isolated photon and a jet, each with transverse momentum above 150 GeV. No significant deviation of the gamma+jet invariant mass distribution from the background-only hypothesis is found. Limits are set at 95% confidence level on the cross sections of generic Gaussian-shaped signals and of a few benchmark phenomena beyond the Standard Model: excited quarks with vector-like couplings to the Standard Model particles, and non-thermal quantum black holes in two models of extra spatial dimensions. The minimum excluded visible cross sections for Gaussian-shaped resonances with width-to-mass ratios of 2% decrease from about 6 fb for a mass of 1.5 TeV to about 0.8 fb for a mass of 5 TeV. The minimum excluded visible cross sections for Gaussian-shaped resonances with width-to-mass ratios of 15% decrease from about 50 fb for a mass of 1.5 TeV to about 1.0 fb for a mass of 5 TeV. Excited quarks are excluded below masses of 4.4 TeV, and non-thermal quantum black holes are excluded below masses of 3.8 (6.2) TeV for Randall-Sundrum (Arkani-Hamed-Dimopoulous-Dvali) models with one (six) extra dimensions.
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ATLAS Collaboration(Aad, G. et al), Alvarez Piqueras, D., Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fernandez Martinez, P., et al. (2016). Measurement of the charge asymmetry in top-quark pair production in the lepton-plus-jets final state in pp collision data at root s=8 TeV with the ATLAS detector. Eur. Phys. J. C, 76(2), 87–30pp.
Abstract: This paper reports inclusive and differential measurements of the t (t) over bar charge asymmetry A(C) in 20.3 fb(-1) of root s = 8 TeV pp collisions recorded by the ATLAS experiment at the Large Hadron Collider at CERN. Three differential measurements are performed as a function of the invariant mass, transverse momentum and longitudinal boost of the t (t) over bar system. The t (t) over bar pairs are selected in the single-lepton channels (e or mu) with at least four jets, and a likelihood fit is used to reconstruct the t (t) over bar event kinematics. A Bayesian unfolding procedure is performed to infer the asymmetry at parton level from the observed data distribution. The inclusive t (t) over bar charge asymmetry is measured to be A(C) = 0.009 +/- 0.005 (stat. + syst.). The inclusive and differential measurements are compatible with the values predicted by the Standard Model.
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Geng, L. S., & Oset, E. (2016). Novel nonperturbative approach for radiative (B)over-bar(0)((B)over-bar(s)(0)) -> J/psi gamma decays. Phys. Rev. D, 94(1), 014018–11pp.
Abstract: Radiative (B) over bar (0)((B) over bar (0)(s)) -> J/psi gamma decays provide an interesting case to test our understanding of ( non) perturbative QCD and eventually to probe physics beyond the standard model. Recently, the LHCb Collaboration reported an upper bound, updating the results of the BABAR Collaboration. Previous theoretical predictions based on QCD factorization or perturbative QCD have shown large variations due to different treatment of nonfactorizable contributions and meson-photon transitions. In this paper, we report on a novel approach to estimate the decay rates, which is based on a recently proposed model for B decays and the vector meson dominance hypothesis, widely tested in the relevant energy regions. The predicted branching ratios are Br[(B) over bar (0) -> J/psi gamma] = (3.50 +/- 0.34(-0.63)(+1.12)) x 10(-8) and Br[(B) over bar (0)(s) -> J/psi gamma] = (7.20 +/- 0.68(-1.30)(+2.31)) x 10(-7). The first uncertainty is systematic and the second is statistical, originating from the experimental (B) over bar (0)(s) -> J/psi gamma branching ratio.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2016). Tests of CPT symmetry in B-0-(B)over-bar(0) mixing and in B-0 -> c(c)over-barK(0) decays. Phys. Rev. D, 94(1), 011101–7pp.
Abstract: Using the eight time dependences e(-Gamma t)(1+C(i)cos Delta mt+S(i)sin Delta mt) for the decays Upsilon (4S) -> B-0(B) over bar (0) -> f(j)f(k), with the decay into a flavor-specific state f(j) = l(+/-)X before or after the decay into a CP eigenstate f(k) = c (c) over barK(S,L), as measured by the BABAR experiment, we determine the three CPT-sensitive parameters Re(z) and Im(z) in B-0-(B) over bar (0) mixing and vertical bar(A) over bar /A vertical bar in B-0 -> c (c) over barK(0) decays. We find Im(z) = 0.010 +/- 0.030 +/- 0.013, Re(z) = -0.065 +/- 0.028 +/- 0.014, and vertical bar(A) over bar /A vertical bar = 0.999 +/- 0.023 +/- 0.017, in agreement with CPT symmetry.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2016). Model-Independent Evidence for J/psi p Contributions to Lambda(0)(b) -> J/psi pK(-) Decays. Phys. Rev. Lett., 117(8), 082002–9pp.
Abstract: The data sample of Lambda(0)(b) -> J/psi pK(-) decays acquired with the LHCb detector from 7 and 8 TeV pp collisions, corresponding to an integrated luminosity of 3 fb(-1), is inspected for the presence of J/psi p or J/psi K- contributions with minimal assumptions about K(-)p contributions. It is demonstrated at more than nine standard deviations that Lambda(0)(b) -> J/psi pK(-) decays cannot be described with K- p contributions alone, and that J/psi K- contributions play a dominant role in this incompatibility. These model-independent results support the previously obtained model-dependent evidence for P-c(+)-> J/psi p charmonium-pentaquark states in the same data sample.
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Di Valentino, E., Giusarma, E., Mena, O., Melchiorri, A., & Silk, J. (2016). Cosmological limits on neutrino unknowns versus low redshift priors. Phys. Rev. D, 93(8), 083527–11pp.
Abstract: Recent cosmic microwave background (CMB) temperature and polarization anisotropy measurements from the Planck mission have significantly improved previous constraints on the neutrino masses as well as the bounds on extended models with massless or massive sterile neutrino states. However, due to parameter degeneracies, additional low redshift priors are mandatory in order to sharpen the CMB neutrino bounds. We explore here the role of different priors on low redshift quantities, such as the Hubble constant, the cluster mass bias, and the reionization optical depth tau. Concerning current priors on the Hubble constant and the cluster mass bias, the bounds on the neutrino parameters may differ appreciably depending on the choices adopted in the analyses. With regard to future improvements in the priors on the reionization optical depth, a value of tau = 0.05 +/- 0.01, motivated by astrophysical estimates of the reionization redshift, would lead to Sigma m(nu) < 0.0926 eV at 90% C.L., when combining the full Planck measurements, baryon acoustic oscillation, and Planck clusters data, thereby opening the window to unravel the neutrino mass hierarchy with existing cosmological probes.
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Bai, Y., Lu, R., Lu, S. D., Salvado, J., & Stefanek, B. A. (2016). Three twin neutrinos: Evidence from LSND and MiniBooNE. Phys. Rev. D, 93(7), 073004–11pp.
Abstract: We construct a neutrino model of three twin neutrinos in light of the neutrino appearance excesses at LSND and MiniBooNE. The model, which includes a twin parity, naturally predicts identical lepton Yukawa structures in the Standard Model and the twin sectors. As a result, a universal mixing angle controls all three twin neutrino couplings to the Standard Model charged leptons. This mixing angle is predicted to be the ratio of the electroweak scale over the composite scale of the Higgs boson and has the right order of magnitude to fit the data. The heavy twin neutrinos decay within the experimental lengths into active neutrinos plus a long-lived Majoron and can provide a good fit, at around the 4 sigma confidence level, to the LSND and MiniBooNE appearance data while simultaneously satisfying the disappearance constraints. For the Majorana neutrino case, the fact that neutrinos have a larger scattering cross section than antineutrinos provides a natural explanation to MiniBooNE's observation of a larger antineutrino appearance excess.
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