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Campanario, F., Roth, R., & Zeppenfeld, D. (2015). QCD radiation in WH and WZ production and anomalous coupling measurements. Phys. Rev. D, 91(5), 054039–10pp.
Abstract: We study QCD radiation for the WH and WZ production processes at the LHC. We identify the regions sensitive to anomalous couplings, by considering jet observables, computed at next-to-leading-order QCD with the use of the Monte Carlo program VBFNLO. Based on these observations, we propose the use of a dynamical jet veto. The dynamical jet veto avoids the problem of large logarithms depending on the veto scale, hence providing more reliable predictions and simultaneously increasing the sensitivity to anomalous coupling searches, especially in the WZ production process.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2015). Measurement of the D-0 -> pi(-)e(+)nu(e) differential decay branching fraction as a function of q(2) and study of form factor parametrizations. Phys. Rev. D, 91(5), 052022–25pp.
Abstract: Based on a sample of 500 million e(+)e(-) -> c (c) over bar events recorded by the BABAR detector at c. m. energies of close to 10.6 GeV, we report on a study of the decay D0 ->pi(-)e(+)nu(e). We measure the ratio of branching fractions, R-D = B(D-0 -> pi(-)e(+)nu(e))/beta(D-0 -> K-pi(+)) = 0.0713 +/- 0.0017(stat) +/- 0.0024(syst), and use the present world average for B(D-0 -> K-pi(+)) to obtain B(D-0 -> pi(-)e(+)nu e) = (2.770 +/- 0.068(stat) +/- 0.092(syst) +/- 0.037(ext)) x 10(-3) where the third error accounts for the uncertainty on the branching fraction for the reference channel. The measured dependence of the differential branching fraction on q(2), the four-momentum transfer squared between the D and the pi meson, is compared to various theoretical predictions for the hadronic form factor, f(+,D)(pi)(q(2)), and the normalization vertical bar V-cd vertical bar x f(+,D)(pi)(q(2) = 0) = 0.1374 +/- 0.0038(stat) +/- 0.0022(sys)t +/- 0.0009(ext). is extracted from a fit to data. Using the most recent LQCD prediction of f(+,D)(pi)(q(2) = 0) = 0.666 +/- 0.029, we obtain vertical bar V-cd vertical bar = 0.206 +/- 0.007(exp) +/- 0.009(LQCD). Assuming, instead, vertical bar V-cd vertical bar = vertical bar V-us vertical bar = 0.2252 +/- 0.0009, we obtain f(+,D)(pi)(q(2) = 0) = 0.610 +/- 0.020(exp) +/- 0.005(ext). The q(2) dependence of f(+,D)(pi)(q(2)) is compared to a variety of multipole parametrizations. This information is applied to B-0 -> pi(-)e(+)nu(e) decays and, combined with an earlier B-0 -> pi(-)e(+)nu(e) measurement by BABAR, is used to derive estimates of vertical bar V-ub vertical bar.
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Beneke, M., Hellmann, C., & Ruiz-Femenia, P. (2015). Heavy neutralino relic abundance with Sommerfeld enhancements – a study of pMSSM scenarios. J. High Energy Phys., 03(3), 162–37pp.
Abstract: We present a detailed discussion of Sommerfeld enhancements in neutralino dark matter relic abundance calculations for several popular benchmark scenarios in the general MSSM. Our analysis is focused on models with heavy wino- and higgsino-like neutralino LSI' and models interpolating between these two scenarios. This work is the first phenomenological application of effective field theory methods that we have developed in earlier work and that allow for the consistent study of Sommerfeld enhancements in nonrelativistic neutralino and chargino co-annihilation reactions within the general MSSM, away from the pure-wino and pure-higgsino limits.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fernandez Martinez, P., Ferrer, A., et al. (2015). Search for Higgs and Z Boson Decays to J/psi gamma and Upsilon(nS)gamma with the ATLAS Detector. Phys. Rev. Lett., 114(12), 121801–19pp.
Abstract: A search for the decays of the Higgs and Z bosons to J/psi gamma and Upsilon(nS)gamma (n = 1,2,3) is performed with pp collision data samples corresponding to integrated luminosities of up to 20.3 fb(-1) collected at root s = 8 TeV with the ATLAS detector at the CERN Large Hadron Collider. No significant excess of events is observed above expected backgrounds and 95% C.L. upper limits are placed on the branching fractions. In the J/psi gamma final state the limits are 1.5 x 10(-3) and 2.6 x 10(-6) for the Higgs and Z boson decays, respectively, while in the Upsilon(1S, 2S, 3S)gamma. final states the limits are (1.3, 1.9, 1.3) x 10(-3) and (3.4, 6.5, 5.4) x 10(-6), respectively.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2015). Measurement of the branching fractions of the radiative leptonic tau decays tau -> e gamma v(v)over-bar and tau -> μgamma v(v)over-bar at BABAR. Phys. Rev. D, 91(5), 051103–8pp.
Abstract: We perform a measurement of the tau -> l gamma v (v) over bar (l = e, mu) branching fractions for a minimum photon energy of 10 MeV in the tau rest frame, using 431 fb(-1) of e(+) e(-) collisions collected at the center-of-mass energy of the Upsilon(4S) resonance with the BABAR detector at the PEP-II storage rings. We find B(tau -> μgamma v (v) over bar = (3.69 +/- 0.03 +/- 0.10) x 10(-3) and B(tau -> e gamma v (v) over bar = (1.847 +/- 0.015 +/- 0.052) x 10(-2), where the first quoted error is statistical and the second is systematic. These results are substantially more precise than previous measurements.
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