BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2011). Search for CP violation using T-odd correlations in D(+) -> K(+)K(S)(0) pi(+)pi(-) and D(s)(+) -> K(+)K(S)(0) pi(+)pi(-) decays. Phys. Rev. D, 84(3), 031103–9pp.
Abstract: We search for CP violation in a sample of 20 000 Cabibbo-suppressed decays, D(+) -> K(+)K(S)(0)pi(+)pi(-), and 30 000 Cabibbo-favored decays, D(+) -> K(+)K(S)(0)pi(+)pi(-). We use 520 fb(-1) of data recorded by the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider operating at center of mass energies near 10.6 GeV. We search for CP violation in the difference between the T-odd asymmetries obtained using triple product correlations of the D(+)(D(s)(+)) and D(-)(D(s)(-)) decays, respectively. The T violation parameter values obtained are A(T)(D(+)) = (-12.0 +/- 10.0(stat) +/- 4.6(syst)) x 10(-3) and A(T)(D(s)(+)) = (-13.6 +/- 7.7(stat) +/- 3.4(syst)) x 10(-3), which are consistent with the standard model expectations.
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Boucenna, M. S., & Profumo, S. (2011). Direct and indirect singlet scalar dark matter detection in the lepton-specific two-Higgs-doublet model. Phys. Rev. D, 84(5), 055011–7pp.
Abstract: A recent study of gamma-ray data from the Galactic center motivates the investigation of light (similar to 7-10 GeV) particle dark matter models featuring tau-lepton pairs as dominant annihilation final state. The lepton-specific two-Higgs-doublet model provides a natural framework where light, singlet scalar dark matter can pair-annihilate dominantly into tau leptons. We calculate the nucleon-dark matter cross section for singlet scalar dark matter within the lepton-specific two-Higgs-doublet model framework, and compare with recent results from direct detection experiments. We study how direct dark matter searches can be used to constrain the dark matter interpretation of gamma-ray observations, for different dominant annihilation final states. We show that models exist with the correct thermal relic abundance that could fit the claimed gamma-ray excess from the Galactic center region and have direct detection cross sections of the order of what is needed to interpret recent anomalous events reported by direct detection experiments.
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SciBooNE Collaboration(Cheng, G. et al), Catala-Perez, J., Gomez-Cadenas, J. J., & Sorel, M. (2011). Measurement of K(+) production cross section by 8 GeV protons using high-energy neutrino interactions in the SciBooNE detector. Phys. Rev. D, 84(1), 012009–22pp.
Abstract: The SciBooNE Collaboration reports K(+) production cross section and rate measurements using high-energy daughter muon neutrino scattering data off the SciBar polystyrene (C(8)H(8)) target in the SciBooNE detector. The K(+) mesons are produced by 8 GeV protons striking a beryllium target in Fermilab Booster Neutrino Beam line (BNB). Using observed neutrino and antineutrino events in SciBooNE, we measure d(2)sigma/dpd Omega = (5.34 +/- 0.76) mb/(GeV/c x sr) for p + Be -> K(+) + X at mean K(+) energy of 3.9 GeVand angle (with respect to the proton beam direction) of 3.7 degrees, corresponding to the selected K(+) sample. Compared to Monte Carlo predictions using previous higher energy K(+) production measurements, this measurement, which uses the NUANCE neutrino interaction generator, is consistent with a normalization factor of 0.85 +/- 0.12. This agreement is evidence that the extrapolation of the higher energy K(+) measurements to an 8 GeV beam energy using Feynman scaling is valid. This measurement reduces the error on the K(+) production cross section from 40% to 14%.
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Gunion, J. F., Lopez-Fogliani, D. E., Roszkowski, L., Ruiz de Austri, R., & Varley, T. A. (2011). Next-to-minimal supersymmetric model Higgs scenarios for partially universal GUT scale boundary conditions. Phys. Rev. D, 84(5), 055026–17pp.
Abstract: We examine the extent to which it is possible to realize the NMSSM “ideal Higgs” models espoused in several papers by Gunion et al. in the context of partially universal GUT scale boundary conditions. To this end we use the powerful methodology of nested sampling. We pay particular attention to whether ideal-Higgs-like points not only pass LEP constraints but are also acceptable in terms of the numerous constraints now available, including those from the Tevatron and B-factory data, (g – 2)(mu) and the relic density Omega h(2). In general for this particular methodology and range of parameters chosen, very few points corresponding to said previous studies were found, and those that were found were at best 2 sigma away from the preferred relic density value. Instead, there exist a class of points, which combine a mostly singlet-like Higgs with a mostly singlino-like neutralino coannihilating with the lightest stau, that are able to effectively pass all implemented constraints in the region 80 < m(h) < 100. It seems that the spin-independent direct detection cross section acts as a key discriminator between ideal Higgs points and the hard to detect singlino-like points.
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MiniBooNE Collaboration(Aguilar-Arevalo, A. A. et al), & Sorel, M. (2011). Measurement of the neutrino component of an antineutrino beam observed by a nonmagnetized detector. Phys. Rev. D, 84(7), 072005–14pp.
Abstract: Two methods are employed to measure the neutrino flux of the antineutrino-mode beam observed by the MiniBooNE detector. The first method compares data to simulated event rates in a high-purity nu(mu)-induced charged-current single pi(+) (CC1 pi(+)) sample while the second exploits the difference between the angular distributions of muons created in nu(mu) and nu(mu) charged-current quasielastic (CCQE) interactions. The results from both analyses indicate the prediction of the neutrino flux component of the predominately antineutrino beam is overestimated-the CC1 pi(+) analysis indicates the predicted nu(mu) flux should be scaled by 0: 76 +/- 0: 11, while the CCQE angular fit yields 0: 65 +/- 0: 23. The energy spectrum of the flux prediction is checked by repeating the analyses in bins of reconstructed neutrino energy, and the results show that the spectral shape is well-modeled. These analyses are a demonstration of techniques for measuring the neutrino contamination of antineutrino beams observed by future nonmagnetized detectors.
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BABAR Collaboration(Lees, J. P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Searches for rare or forbidden semileptonic charm decays. Phys. Rev. D, 84(7), 072006–13pp.
Abstract: We present searches for rare or forbidden charm decays of the form X(c)(+) -> h(+/-)l(+/-)l((l)+), where X(c)(+) is a charm hadron (D(+), D(s)(+), or A(c)(+)), h +/- is a pion, kaon, or proton, and l((l)+/-) is an electron or muon. The analysis is based on 384 fb(-1) of e(+)e(-) annihilation data collected at or close to the gamma(4S) resonance with the BABAR detector at the SLAC National Accelerator Laboratory. No significant signal is observed for any of the 35 decay modes that are investigated. We establish 90% confidence-level upper limits on the branching fractions between 1 x 10(-6) and 44 x 10(-6) depending on the channel. In most cases, these results represent either the first limits or significant improvements on existing limits for the decay modes studied.
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BABAR Collaboration(Lees, J. P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Study of radiative bottomonium transitions using converted photons. Phys. Rev. D, 84(7), 072002–17pp.
Abstract: We use (111 +/- 1) million Gamma(3S) and (89 +/- 1) million Gamma(2S) events recorded by the BABAR detector at the PEP-II B-factory at SLAC to perform a study of radiative transitions between bottomonium states using photons that have been converted to e(+)e(-) pairs by the detector material. We observe Gamma(3S) -> gamma chi b(0,2)(1P) decay, make precise measurements of the branching fractions for chi b(1,2)(1P, 2P) -> gamma Gamma(1S) and chi b(1,2)(2P) -> gamma Gamma(2S) decays, and search for radiative decay to the eta(b)(1S) and eta(b)(2S) states.
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Nieves, J., Pich, A., & Ruiz Arriola, E. (2011). Large-N(C) properties of the rho and f(0)(600) mesons from unitary resonance chiral dynamics. Phys. Rev. D, 84(9), 096002–20pp.
Abstract: We construct pi pi amplitudes that fulfill exact elastic unitarity, account for one-loop chiral perturbation theory contributions and include all 1/N(C) leading terms, with the only limitation of considering just the lowest-lying nonet of exchanged resonances. Within such a scheme, the N(C) dependence of sigma and rho masses and widths is discussed. Robust conclusions are drawn in the case of the rho resonance, confirming that it is a stable meson in the limit of a large number of QCD colors, N(C). Less definitive conclusions are reached in the scalar-isoscalar sector. With the present quality of data, we cannot firmly conclude whether or not the N(C) = 3 f(0)(600) resonance completely disappears at large N(C) or if it has a subdominant component in its structure, which would become dominant for a number of quark colors sufficiently large.
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Rodejohann, W., & Valle, J. W. F. (2011). Symmetrical parametrizations of the lepton mixing matrix. Phys. Rev. D, 84(7), 073011–6pp.
Abstract: Advantages of the original symmetrical form of the parametrization of the lepton mixing matrix are discussed. It provides a conceptually more transparent description of neutrino oscillations and lepton number violating processes like neutrinoless double beta decay, clarifying the significance of Dirac and Majorana phases. It is also ideal for parametrizing scenarios with light sterile neutrinos.
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Agullo, I., Navarro-Salas, J., Olmo, G. J., & Parker, L. (2011). Remarks on the renormalization of primordial cosmological perturbations. Phys. Rev. D, 84(10), 107304–5pp.
Abstract: We briefly review the need to perform renormalization of inflationary perturbations to properly work out the physical power spectra. We also summarize the basis of (momentum-space) renormalization in curved spacetime and address several misconceptions found in recent literature on this subject.
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