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Pato, M., Baudis, L., Bertone, G., Ruiz de Austri, R., Strigari, L. E., & Trotta, R. (2011). Complementarity of dark matter direct detection targets. Phys. Rev. D, 83(8), 083505–11pp.
Abstract: We investigate the reconstruction capabilities of the dark matter mass and spin-independent cross section from future ton-scale direct detection experiments using germanium, xenon, or argon as targets. Adopting realistic values for the exposure, energy threshold, and resolution of dark matter experiments which will come online within 5 to 10 years, the degree of complementarity between different targets is quantified. We investigate how the uncertainty in the astrophysical parameters controlling the local dark matter density and velocity distribution affects the reconstruction. For a 50 GeV WIMP, astrophysical uncertainties degrade the accuracy in the mass reconstruction by up to a factor of similar to 4 for xenon and germanium, compared to the case when astrophysical quantities are fixed. However, the combination of argon, germanium, and xenon data increases the constraining power by a factor of similar to 2 compared to germanium or xenon alone. We show that future direct detection experiments can achieve self-calibration of some astrophysical parameters, and they will be able to constrain the WIMP mass with only very weak external astrophysical constraints.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2011). Measurement of the t(t)over-bar production cross section with an in situ calibration of b-jet identification efficiency. Phys. Rev. D, 83(7), 071102–8pp.
Abstract: A measurement of the top-quark pair-production cross section in p (p) over bar collisions at root s = 1.96 TeV using data corresponding to an integrated luminosity of 1.12 fb(-1) collected with the Collider Detector at Fermilab is presented. Decays of top-quark pairs into the final states ev + jets and μv+ jets are selected, and the cross section and the b-jet identification efficiency are determined using a new measurement technique which requires agreement between the measured cross sections with exactly one and with multiple identified b quarks from the top-quark decays. Assuming a top-quark mass of 175 GeV/c(2), a cross section of 8.5 +/- 0.6(stat) +/- 0.7(syst)pb is measured.
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Jung, M., Pich, A., & Tuzon, P. (2011). B(bar) -> X_s gamma rate and CP asymmetry within the aligned two-Higgs-doublet model. Phys. Rev. D, 83(7), 074011–8pp.
Abstract: In the two-Higgs-doublet model the alignment of the Yukawa matrices in flavor space guarantees the absence of flavor-changing neutral currents at tree level, while introducing new sources for CP violation parametrized in a very economical way [Antonio Pich and Paula Tuzon, Phys. Rev. D 80, 091702 (2009)]. This implies a potentially large influence in a number of processes, b -> s gamma being a prominent example where rather high experimental and theoretical precision meet. We analyze the CP rate asymmetry in this inclusive decay and determine the resulting constraints on the model parameters. We demonstrate the compatibility with previously obtained limits [Martin Jung, Antonio Pich, and Paula Tuzon, J. High Energy Phys. 11 (2010) 003]. Moreover, we extend the phenomenological analysis of the branching ratio, and examine the influence of resulting correlations on the like-sign dimuon charge asymmetry in B decays.
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Bodenstein, S., Bordes, J., Dominguez, C. A., Peñarrocha, J., & Schilcher, K. (2011). QCD sum rule determination of the charm-quark mass. Phys. Rev. D, 83(7), 074014–4pp.
Abstract: QCD sum rules involving mixed inverse moment integration kernels are used in order to determine the running charm-quark mass in the (MS) over bar scheme. Both the high and the low energy expansion of the vector current correlator are involved in this determination. The optimal integration kernel turns out to be of the form p(s) = 1 -(s(0)/s)(2), where s(0) is the onset of perturbative QCD. This kernel enhances the contribution of the well known narrow resonances, and reduces the impact of the data in the range s similar or equal to 20-25 GeV2. This feature leads to a substantial reduction in the sensitivity of the results to changes in s(0), as well as to a much reduced impact of the experimental uncertainties in the higher resonance region. The value obtained for the charm-quark mass in the (MS) over bar scheme at a scale of 3 GeV is (m) over bar (c)(3 GeV) = 987 +/- 9 MeV, where the error includes all sources of uncertainties added in quadrature.
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Gomez Dumm, D., Noguera, S., & Scoccola, N. N. (2011). Pion radiative weak decays in nonlocal chiral quark models. Phys. Lett. B, 698(3), 236–242.
Abstract: We analyze the radiative pion decay pi(+) -> e(+) nu(e)gamma within nonlocal chiral quark models that include wave function renormalization. In this framework we calculate the vector and axial-vector form factors F-V and F-A at q(2) = 0 – where q(2) is the e(+) nu(e) squared invariant mass – and the slope a of F-V (q(2)) at q(2) -> 0. The calculations are carried out considering different nonlocal form factors, in particular those taken from lattice QCD evaluations, showing a reasonable agreement with the corresponding experimental data. The comparison of our results with those obtained in the (local) NJL model and the relation of F-V and a with the form factor in pi(0) -> gamma*gamma decays are discussed.
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