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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Measurement of the top quark mass in the dilepton channel using m(T2) at CDF. Phys. Rev. D, 81(3), 031102–9pp.
Abstract: We present measurements of the top quark mass using m(T2), a variable related to the transverse mass in events with two missing particles. We use the template method applied to t (t) over bar dilepton events produced in p (p) over bar collisions at Fermilab's Tevatron Collider and collected by the CDF detector. From a data sample corresponding to an integrated luminosity of 3.4 fb(-1), we select 236 t (t) over bar candidate events. Using the m(T2) distribution, we measure the top quark mass to be M-top = 168.0(-4.0)(4.8)(stat) +/- 2.9(syst) GeV/c(2). By combining m(T2) with the reconstructed top quark mass distributions based on a neutrino weighting method, we measure M-top = 169.3 +/- 2.7(stat) +/- 3.2(syst) GeV/c(2). This is the first application of the m(T2) variable in a mass measurement at a hadron collider.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Measurements of branching fraction ratios and CP asymmetries in B-+/- -> DCPK +/- decays in hadron collisions. Phys. Rev. D, 81(3), 031105–9pp.
Abstract: We reconstruct B-+/- -> DK +/- decays in a data sample collected by the CDF II detector at the Tevatron collider corresponding to 1 fb(-1) of integrated luminosity. We select decay modes where the D meson decays to either K-pi(+) (flavor eigenstate) or K-K+, pi(-)pi(+) (CP-even eigenstates), and measure the direct CP asymmetry A(CP+) = 0.39 +/- 0.17(stat) +/- 0.04(syst), and the double ratio of CP-even to flavor eigenstate branching fractions RCP+ = 1.30 +/- 0.24(stat) +/- 0.12(syst). These measurements will improve the determination of the Cabibbo-Kobayashi-Maskawa angle gamma. They are performed here for the first time using data from hadron collisions.
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Taoso, M., Iocco, F., Meynet, G., Bertone, G., & Eggenberger, P. (2010). Effect of low mass dark matter particles on the Sun. Phys. Rev. D, 82(8), 083509–14pp.
Abstract: We study the effect of dark matter (DM) particles in the Sun, focusing, in particular, on the possible reduction of the solar neutrinos flux due to the energy carried away by DM particles from the innermost regions of the Sun, and to the consequent reduction of the temperature of the solar core. We find that in the very low-mass range between 4 and 10 GeV, recently advocated to explain the findings of the DAMA and CoGent experiments, the effects on neutrino fluxes are detectable only for DM models with a very small, or vanishing, self-annihilation cross section, such as the so-called asymmetric DM models, and we study the combination of DM masses and spin-dependent cross sections which can be excluded with current solar neutrino data. Finally, we revisit the recent claim that DM models with large self-interacting cross sections can lead to a modification of the position of the convective zone, alleviating or solving the solar composition problem. We show that when the "geometric'' upper limit on the capture rate is correctly taken into account, the effects of DM are reduced by orders of magnitude, and the position of the convective zone remains unchanged.
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CDF Collaboration(Aaltonen, T. et al), Cabrera, S., & Cuenca Almenar, C. (2010). Measurements of the top-quark mass using charged particle tracking. Phys. Rev. D, 81(3), 032002–21pp.
Abstract: We present three measurements of the top-quark mass in the lepton plus jets channel with approximately 1.9 fb(-1) of integrated luminosity collected with the CDF II detector using quantities with minimal dependence on the jet energy scale. One measurement exploits the transverse decay length of b-tagged jets to determine a top-quark mass of 166.9(-8.5)(+9.5)(stat) +/- 2.9(syst) GeV/c(2), and another the transverse momentum of electrons and muons from W-boson decays to determine a top-quark mass of 173.5(-8.9)(+8.8)(stat) +/- 3.8(syst) GeV/c(2). These quantities are combined in a third, simultaneous mass measurement to determine a top-quark mass of 170.7 +/- 6.3(stat) +/- 2.6(syst) GeV/c(2) .
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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., Milanes, D. A., & Oyanguren, A. (2010). Observation of new resonances decaying to D pi and D*pi in inclusive e(+)e(-) collisions near root s=10.58 GeV. Phys. Rev. D, 82(11), 111101–9pp.
Abstract: We present a study of the D+pi(-), D-0 pi(+), and D*(+)pi(-) systems in inclusive e(+)e(-)-> c (c) over bar interactions in a search for new excited D meson states. We use a data set, consisting of similar to 454 fb(-1), collected at center-of-mass energies near 10.58 GeV by the BABAR detector at the SLAC PEP-II asymmetric-energy collider. We observe, for the first time, candidates for the radial excitations of the D-0, D*(0), and D*(+), as well as the L = 2 excited states of the D-0 and D+, where L is the orbital angular momentum of the quarks.
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Gamermann, D., Nieves, J., Oset, E., & Ruiz Arriola, E. (2010). Couplings in coupled channels versus wave functions: Application to the X(3872) resonance. Phys. Rev. D, 81(1), 014029–14pp.
Abstract: We perform an analytical study of the scattering matrix and bound states in problems with many physical coupled channels. We establish the relationship of the couplings of the states to the different channels, obtained from the residues of the scattering matrix at the poles, with the wave functions for the different channels. The couplings basically reflect the value of the wave functions around the origin in coordinate space. In the concrete case of the X(3872) resonance, understood as a bound state of D-0(D) over bar*(0) and D+D*(-) (and c.c. From now on, when we refer to D-0(D) over bar*(0), D+D*(-), or D (D) over bar* we are actually referring to the combination of these states with their complex conjugate in order to form a state with positive C-parity), with the D-0(D) over bar*(0) loosely bound, we find that the couplings to the two channels are essentially equal leading to a state of good isospin I = 0 character. This is in spite of having a probability for finding the D-0(D) over bar*(0) state much larger than for D+D*(-) since the loosely bound channel extends further in space. The analytical results, obtained with exact solutions of the Schrodinger equation for the wave functions, can be useful in general to interpret results found numerically in the study of problems with unitary coupled channels methods.
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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., Milanes, D. A., & Oyanguren, A. (2010). Measurement of the absolute branching fractions for D-s(-) -> l(-) (nu)over-bar(l) and extraction of the decay constant f(Ds). Phys. Rev. D, 82(9), 091103–8pp.
Abstract: The absolute branching fractions for the decays D-s(-) -> l(-) (nu) over bar (l) (l = e, mu, or tau) are measured using a data sample corresponding to an integrated luminosity of 521 fb(-1) collected at center-of-mass energies near 10.58 GeV with the BABAR detector at the PEP-II e(+)e(-) collider at SLAC. The number of D-s(-) mesons is determined by reconstructing the recoiling system DKX gamma in events of the type e(+)e(-) -> DKXDs*(-), where D-s*(-) -> D-s(-) gamma and X represents additional pions from fragmentation. The D-s(-) -> l(-) nu(l) events are detected by full or partial reconstruction of the recoiling system DKX gamma l. The branching fraction measurements are combined to determine the D-s(-) decay constant f(Ds) (258.6 +/- 6.4 +/- 7:5) MeV, where the first uncertainty is statistical and the second is systematic.
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Fogli, G. L., Lisi, E., Palazzo, A., & Rotunno, A. M. (2010). Combined analysis of KamLAND and Borexino neutrino signals from Th and U decays in the Earth's interior. Phys. Rev. D, 82(9), 093006–9pp.
Abstract: The KamLAND and Borexino experiments have detected electron antineutrinos produced in the decay chains of natural thorium and uranium (Th and U geoneutrinos). We analyze the energy spectra of current geoneutrino data in combination with solar and long-baseline reactor neutrino data, with marginalized three-neutrino oscillation parameters. We consider the case with unconstrained Th and U event rates in KamLAND and Borexino, as well as cases with fewer degrees of freedom, as obtained by successively assuming for both experiments a common Th/U ratio, a common scaling of Th + U event rates, and a chondritic Th/U value. In combination, KamLAND and Borexino can reject the null hypothesis (no geoneutrino signal) at 5 sigma. Interesting bounds or indications emerge on the Th + U geoneutrino rates and on the Th/U ratio, in broad agreement with typical Earth model expectations. Conversely, the results disfavor the hypothesis of a georeactor in the Earth's core, if its power exceeds a few TW. The interplay of KamLAND and Borexino geoneutrino data is highlighted.
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Fernandez-Martinez, E., Giordano, G., Mena, O., & Mocioiu, I. (2010). Atmospheric neutrinos in ice and measurement of neutrino oscillation parameters. Phys. Rev. D, 82(9), 093011–7pp.
Abstract: The main goal of the IceCube Deep Core array is to search for neutrinos of astrophysical origins. Atmospheric neutrinos are commonly considered as a background for these searches. We show that the very high statistics atmospheric neutrino data can be used to obtain precise measurements of the main oscillation parameters.
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BABAR Collaboration(Aubert, B. et al), Azzolini, V., Lopez-March, N., Martinez-Vidal, F., Milanes, D. A., & Oyanguren, A. (2010). Correlated leading baryon-antibaryon production in e(+)e(-) -> c(c)over-bar -> Lambda(+)(c)(Lambda)over-bar(c)(-)X. Phys. Rev. D, 82(9), 091102–8pp.
Abstract: We present a study of 649 +/- 35 e(+)e(-) -> c (c) over bar events produced at root s approximate to 10.6 GeV containing both Lambda(+)(c) baryon and a (Lambda) over bar (-)(c) antibaryon. The number observed is roughly 4 times that expected if the leading charmed hadron types are uncorrelated, confirming an observation by the CLEO Collaboration. We find a 2-jet topology in these events but very few additional baryons, demonstrating that the primary c and (c) over bar are predominantly contained in a correlated baryon-antibaryon system. In addition to the charmed baryons we observe on average 2.6 +/- 0.2 charged intermediate mesons, predominantly pions, carrying 65% of the remaining energy.
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