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Xie, J. J., Martinez Torres, A., & Oset, E. (2011). Faddeev fixed-center approximation to the N K K(bar) system and the signature of a N*(1920)(1/2+) state. Phys. Rev. C, 83(6), 065207–8pp.
Abstract: We perform a calculation for the three-body N (K) over barK scattering amplitude by using the fixed-center approximation to the Faddeev equations, taking the interaction between N and (K) over bar, N and K, and (K) over bar and K from the chiral unitary approach. The resonant structures show up in the modulus squared of the three-body scattering amplitude and suggest that a N (K) over barK hadron state can be formed. Our results are in agreement with others obtained in previous theoretical works, which claim a new N* resonance around 1920 MeV with spin-parity J(P) = 1/2(+). The existence of these previous works allows us to test the accuracy of the fixed center approximation in the present problem and sets the grounds for possible application in similar problems, as an explorative tool to determine bound or quasibound three-hadron systems.
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Xiao, C. W., Bayar, M., & Oset, E. (2011). NDK, (K)over-barDN, and ND(K)over-bar molecules. Phys. Rev. D, 84(3), 034037–8pp.
Abstract: We investigate theoretically baryon systems made of three hadrons which contain one nucleon and one D meson, and in addition another meson, (D) over tilde, K, or (K) over tilde. The systems are studied using the fixed center approximation to the Faddeev equations. The study is made assuming scattering of a K or a (K) over tilde on a DN cluster, which is known to generate the Lambda(c)(2595), or the scattering of a nucleon on the D (D) over tilde cluster, which has been shown to generate a hidden charm resonance named X(3700). We also investigate the configuration of scattering of N on the KD cluster, which is known to generate the D*(s0)(2317). In all cases we find bound states, with the NDK system, of exotic nature, more bound than the (K) over tilde DN.
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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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Bertolini, S., Di Luzio, L., & Malinsky, M. (2011). Minimal flipped SO(10) x U(1) supersymmetric Higgs model. Phys. Rev. D, 83(3), 035002–28pp.
Abstract: We investigate the conditions on the Higgs sector that allow supersymmetric SO(10) grand unified theories to break spontaneously to the standard electroweak model at the renormalizable level. If one considers Higgs representations of dimension up to the adjoint, a supersymmetric standard model vacuum requires, in most cases, the presence of nonrenormalizable operators. The active role of Planck-induced nonrenormalizable operators in the breaking of the gauge symmetry introduces a hierarchy in the mass spectrum at the grand unified theory scale that may be an issue for gauge unification and proton decay. We show that the minimal Higgs scenario that allows for a renormalizable breaking to the standard model is obtained by considering flipped SO(10) circle times U(1) with one adjoint (45(H)) and two pairs of 16(H) circle plus (16) over bar (H) Higgs representations. We consider a nonanomalous matter content and discuss the embedding of the model in an E-6 grand unified scenario just above the flipped SO(10) scale.
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Calabrese, E., de Putter, R., Huterer, D., Linder, E. V., & Melchiorri, A. (2011). Future CMB constraints on early, cold, or stressed dark energy. Phys. Rev. D, 83(2), 023011–11pp.
Abstract: We investigate future constraints on early dark energy (EDE) achievable by the Planck and CMBPol experiments, including cosmic microwave background (CMB) lensing. For the dark energy, we include the possibility of clustering through a sound speed c(s)(2) < 1 (cold dark energy) and anisotropic stresses parametrized with a viscosity parameter c(vis)(2). We discuss the degeneracies between cosmological parameters and EDE parameters. In particular we show that the presence of anisotropic stresses in EDE models can substantially undermine the determination of the EDE sound speed parameter c(s)(2). The constraints on EDE primordial energy density are however unaffected. We also calculate the future CMB constraints on neutrino masses and find that they are weakened by a factor of 2 when allowing for the presence of EDE, and highly biased if it is incorrectly ignored.
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