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Author Lopez Honorez, L.; Reid, B.A.; Mena, O.; Verde, L.; Jimenez, R. url  doi
openurl 
  Title Coupled dark matter-dark energy in light of near universe observations Type Journal Article
  Year 2010 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.  
  Volume 09 Issue 9 Pages 029 - 36pp  
  Keywords dark energy experiments; dark energy theory; cosmological parameters from LSS  
  Abstract Cosmological analysis based on currently available observations are unable to rule out a sizeable coupling among the dark energy and dark matter fluids. We explore a variety of coupled dark matter-dark energy models, which satisfy cosmic microwave background constraints, in light of low redshift and near universe observations. We illustrate the phenomenology of different classes of dark coupling models, paying particular attention in distinguishing between effects that appear only on the expansion history and those that appear in the growth of structure. We find that while a broad class of dark coupling models are effectively models where general relativity (GR) is modified – and thus can be probed by a combination of tests for the expansion history and the growth of structure -, there is a class of dark coupling models where gravity is still GR, but the growth of perturbations is, in principle modified. While this effect is small in the specific models we have considered, one should bear in mind that an inconsistency between reconstructed expansion history and growth may not uniquely indicate deviations from GR. Our low redshift constraints arise from cosmic velocities, redshift space distortions and dark matter abundance in galaxy voids. We find that current data constrain the dimensionless coupling to be vertical bar xi vertical bar < 0.2, but prospects from forthcoming data are for a significant improvement. Future, precise measurements of the Hubble constant, combined with high-precision constraints on the growth of structure, could provide the key to rule out dark coupling models which survive other tests. We shall exploit as well weak equivalence principle violation arguments, which have the potential to highly disfavour a broad family of coupled models.  
  Address [Lopez Honorez, Laura] UAM, CSIC, Dept Phys, Madrid 28049, Spain, Email: laura.lopez@uam.es  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1475-7516 ISBN Medium  
  Area Expedition Conference  
  Notes (up) ISI:000283576500007 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ elepoucu @ Serial 343  
Permanent link to this record
 

 
Author Wagner, C.; Verde, L.; Boubekeur, L. url  doi
openurl 
  Title N-body simulations with generic non-Gaussian initial conditions I: power spectrum and halo mass function Type Journal Article
  Year 2010 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.  
  Volume 10 Issue 10 Pages 022 - 24pp  
  Keywords power spectrum; cosmological simulations; initial conditions and eternal universe; galaxy clusters  
  Abstract We address the issue of setting up generic non-Gaussian initial conditions for N-body simulations. We consider inflationary-motivated primordial non-Gaussianity where the perturbations in the Bardeen potential are given by a dominant Gaussian part plus a non-Gaussian part specified by its bispectrum. The approach we explore here is suitable for any bispectrum, i.e. it does not have to be of the so-called separable or factorizable form. The procedure of generating a non-Gaussian field with a given bispectrum (and a given power spectrum for the Gaussian component) is not univocal, and care must be taken so that higher-order corrections do not leave a too large signature on the power spectrum. This is so far a limiting factor of our approach. We then run N-body simulations for the most popular inflationary-motivated non-Gaussian shapes. The halo mass function and the non-linear power spectrum agree with theoretical analytical approximations proposed in the literature, even if they were so far developed and tested only for a particular shape (the local one). We plan to make the simulations outputs available to the community via the non-Gaussian simulations comparison project web site http://icc.ub.edu/similar to liciaverde/NGSCP.html.  
  Address [Wagner, Christian; Verde, Licia] Univ Barcelona, ICCUB IEEC, E-08028 Barcelona, Spain, Email: cwagner@icc.ub.edu  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1475-7516 ISBN Medium  
  Area Expedition Conference  
  Notes (up) ISI:000283577600013 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ elepoucu @ Serial 339  
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Author HARP Collaboration (Apollonio, M. et al); Burguet-Castell, J.; Cervera-Villanueva, A.; Gomez-Cadenas, J.J.; Martin-Albo, J.; Novella, P.; Sorel, M. url  doi
openurl 
  Title Measurements of forward proton production with incident protons and charged pions on nuclear targets at the CERN Proton Synchroton Type Journal Article
  Year 2010 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 82 Issue 4 Pages 045208 - 33pp  
  Keywords  
  Abstract Measurements of the double-differential proton production cross-section d(2 sigma)/dpd Omega in the range of momentum 0.5 GeV/c <= p < 8.0 GeV/c and angle 0.05 rad <= theta < 0.25 rad in collisions of charged pions and protons on beryllium, carbon, aluminium, copper, tin, tantalum, and lead are presented. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN Proton Synchrotron. Incident particles were identified by an elaborate system of beam detectors and impinged on a target of 5% of a nuclear interaction length. The tracking and identification of the produced particles was performed using the forward spectrometer of the HARP experiment. Results are obtained for the double-differential cross-sections mainly at four incident beam momenta (3, 5, 8, and 12 GeV/c). Measurements are compared with predictions of the GEANT4 and MARS Monte Carlo generators.  
  Address [Bonesini, M.; Ferri, F.] Sez INFN Milano Bicocca, Milan, Italy, Email: maurizio.bonesini@mib.infn.it  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0556-2813 ISBN Medium  
  Area Expedition Conference  
  Notes (up) ISI:000283579000005 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ elepoucu @ Serial 346  
Permanent link to this record
 

 
Author HADES Collaboration (Agakishiev, G. et al); Diaz, J.; Gil, A. url  doi
openurl 
  Title In-medium effects on K-0 mesons in relativistic heavy-ion collisions Type Journal Article
  Year 2010 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 82 Issue 4 Pages 044907 - 9pp  
  Keywords  
  Abstract We present the transverse momentum spectra and rapidity distributions of pi(-) and K-S(0) in Ar + KCl reactions at a beam kinetic energy of 1.756 A GeV measured with the High Acceptance Di-Electron Spectrometer (HADES). The reconstructed K-S(0) sample is characterized by good event statistics for a wide range in momentum and rapidity. We compare the experimental pi(-) and K-S(0) distributions to predictions by the Isospin Quantum Molecular Dynamics (IQMD) model. The model calculations show that K-S(0) at low transverse momenta constitute a particularly well-suited tool to investigate the kaon in-medium potential. Our K-S(0) data suggest a strong repulsive in-medium K-0 potential of about 40 MeV strength.  
  Address [Agakishiev, G.; Destefanis, M.; Gilardi, C.; Kirschner, D.; Kuehn, W.; Lange, J. S.; Metag, V.; Mishra, D.; Pechenov, V.; Pechenova, O.; Cavalcanti, T. Perez; Spataro, S.; Spruck, B.] Univ Giessen, Inst Phys 2, D-35392 Giessen, Germany, Email: laura.fabbietti@ph.tum.de  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0556-2813 ISBN Medium  
  Area Expedition Conference  
  Notes (up) ISI:000283648400009 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ elepoucu @ Serial 334  
Permanent link to this record
 

 
Author Tolos, L.; Molina, R.; Oset, E.; Ramos, A. url  doi
openurl 
  Title (K)over-bar* mesons in dense matter Type Journal Article
  Year 2010 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 82 Issue 4 Pages 045210 - 12pp  
  Keywords  
  Abstract We study the properties of (K) over bar* mesons in nuclear matter using a unitary approach in coupled channels within the framework of the local hidden gauge formalism and incorporating the (K) over bar pi decay channel in matter. The in-medium (K) over bar *N interaction accounts for Pauli blocking effects and incorporates the (K) over bar* self-energy in a self-consistent manner. We also obtain the (K) over bar* (off-shell) spectral function and analyze its behavior at finite density and momentum. At a normal nuclear matter density, the (K) over bar* meson feels a moderately attractive potential, while the (K) over bar* width becomes five times larger than in free space. We estimate the transparency ratio of the gamma A -> K+K*(-) A` reaction, which we propose as a feasible scenario at the present facilities to detect changes in the properties of the (K) over bar* meson in nuclear medium.  
  Address [Tolos, L.] Univ Groningen, Theory Grp KVI, NL-9747 AA Groningen, Netherlands, Email: tolos@kvi.nl  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0556-2813 ISBN Medium  
  Area Expedition Conference  
  Notes (up) ISI:000283648400011 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ elepoucu @ Serial 335  
Permanent link to this record
 

 
Author CDF Collaboration (Aaltonen, T. et al); Cabrera, S. url  doi
openurl 
  Title Search for the supersymmetric partner of the top quark in p(p)over-bar collisions at root s = 1.96 TeV Type Journal Article
  Year 2010 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 82 Issue 9 Pages 092001 - 16pp  
  Keywords  
  Abstract We present a search for the lightest supersymmetric partner of the top quark in proton-antiproton collisions at a center-of-mass energy root s = 1: 96 TeV. This search was conducted within the framework of the R parity conserving minimal supersymmetric extension of the standard model, assuming the stop decays dominantly to a lepton, a sneutrino, and a bottom quark. We searched for events with two oppositely-charged leptons, at least one jet, and missing transverse energy in a data sample corresponding to an integrated luminosity of 1 fb(-1) collected by the Collider Detector at Fermilab experiment. No significant evidence of a stop quark signal was found. Exclusion limits at 95% confidence level in the stop quark versus sneutrino mass plane are set. Stop quark masses up to 180 GeV/c(2) are excluded for sneutrino masses around 45 GeV/c(2), and sneutrino masses up to 116 GeV/c(2) are excluded for stop quark masses around 150 GeV/c(2).  
  Address [Aaltonen, T.; Brucken, E.; Devoto, F.; Mehtala, P.; Orava, R.] Univ Helsinki, Dept Phys, Div High Energy Phys, FIN-00014 Helsinki, Finland  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes (up) ISI:000283709700001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 269  
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Author Aguiar, P.; Rafecas, M.; Ortuño, J.E.; Kontaxakis, G.; Santos, A.; Pavia, J.; Rosetti, M. doi  openurl
  Title Geometrical and Monte Carlo projectors in 3D PET reconstruction Type Journal Article
  Year 2010 Publication Medical Physics Abbreviated Journal Med. Phys.  
  Volume 37 Issue 11 Pages 5691-5702  
  Keywords 3D PET; iterative reconstruction; list-mode reconstruction; ray-tracing techniques; Monte Carlo simulation; system response matrix  
  Abstract Purpose: In the present work, the authors compare geometrical and Monte Carlo projectors in detail. The geometrical projectors considered were the conventional geometrical Siddon ray-tracer (S-RT) and the orthogonal distance-based ray-tracer (OD-RT), based on computing the orthogonal distance from the center of image voxel to the line-of-response. A comparison of these geometrical projectors was performed using different point spread function (PSF) models. The Monte Carlo-based method under consideration involves an extensive model of the system response matrix based on Monte Carlo simulations and is computed off-line and stored on disk. Methods: Comparisons were performed using simulated and experimental data of the commercial small animal PET scanner rPET. Results: The results demonstrate that the orthogonal distance-based ray-tracer and Siddon ray-tracer using PSF image-space convolutions yield better images in terms of contrast and spatial resolution than those obtained after using the conventional method and the multiray-based S-RT. Furthermore, the Monte Carlo-based method yields slight improvements in terms of contrast and spatial resolution with respect to these geometrical projectors. Conclusions: The orthogonal distance-based ray-tracer and Siddon ray-tracer using PSF image-space convolutions represent satisfactory alternatives to factorizing the system matrix or to the conventional on-the-fly ray-tracing methods for list-mode reconstruction, where an extensive modeling based on Monte Carlo simulations is unfeasible.  
  Address [Aguiar, Pablo] Univ Santiago de Compostela, Dept Fis Particulas, Complexo Hosp Univ Santiago de Compostela, Fdn IDICHUS IDIS, Santiago De Compostela, Spain, Email: pablo.aguiar.fernandez@sergas.es  
  Corporate Author Thesis  
  Publisher Amer Assoc Physicists Medicine Amer Inst Physics Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0094-2405 ISBN Medium  
  Area Expedition Conference  
  Notes (up) ISI:000283747600015 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ elepoucu @ Serial 338  
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Author BABAR Collaboration (del Amo Sanchez, P. et al); Lopez-March, N.; Martinez-Vidal, F.; Milanes, D.A.; Oyanguren, A. url  doi
openurl 
  Title Search for B+ meson decay to a(1)(+)(1260)K*(0)(892) Type Journal Article
  Year 2010 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 82 Issue 9 Pages 091101 - 8pp  
  Keywords  
  Abstract We present a search for the decay B+ -> a(1)(+)(1260)K*(0)(892). The data, collected with the BABAR detector at the SLAC National Accelerator Laboratory, represent 465 X 10(6)B (B) over bar pairs produced in e(+)e(-) annihilation at the energy of the gamma(4S). We find no significant signal and set an upper limit at 90% confidence level on the product of branching fractions B(B+ -> a(1)(+) (1260)K*(0)(892)) X B(a(1)(+)(1260) -> pi(+) pi(-) pi(+)) of 1.8 X 10(-6).  
  Address [Sanchez, P. del Amo; Lees, J. P.; Poireau, V.; Prencipe, E.; Tisserand, V.] Univ Savoie, CNRS, IN2P3, Lab Annecy le Vieux Phys Particules LAPP, F-74941 Annecy Le Vieux, France  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes (up) ISI:000283773400001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ elepoucu @ Serial 345  
Permanent link to this record
 

 
Author Oliver, J.F.; Rafecas, M. doi  openurl
  Title Improving the singles rate method for modeling accidental coincidences in high-resolution PET Type Journal Article
  Year 2010 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.  
  Volume 55 Issue 22 Pages 6951-6971  
  Keywords  
  Abstract Random coincidences ('randoms') are one of the main sources of image degradation in PET imaging. In order to correct for this effect, an accurate method to estimate the contribution of random events is necessary. This aspect becomes especially relevant for high-resolution PET scanners where the highest image quality is sought and accurate quantitative analysis is undertaken. One common approach to estimate randoms is the so-called singles rate method (SR) widely used because of its good statistical properties. SR is based on the measurement of the singles rate in each detector element. However, recent studies suggest that SR systematically overestimates the correct random rate. This overestimation can be particularly marked for low energy thresholds, below 250 keV used in some applications and could entail a significant image degradation. In this work, we investigate the performance of SR as a function of the activity, geometry of the source and energy acceptance window used. We also investigate the performance of an alternative method, which we call 'singles trues' (ST) that improves SR by properly modeling the presence of true coincidences in the sample. Nevertheless, in any real data acquisition the knowledge of which singles are members of a true coincidence is lost. Therefore, we propose an iterative method, STi, that provides an estimation based on ST but which only requires the knowledge of measurable quantities: prompts and singles. Due to inter-crystal scatter, for wide energy windows ST only partially corrects SR overestimations. While SR deviations are in the range 86-300% (depending on the source geometry), the ST deviations are systematically smaller and contained in the range 4-60%. STi fails to reproduce the ST results, although for not too high activities the deviation with respect to ST is only a few percent. For conventional energy windows, i.e. those without inter-crystal scatter, the ST method corrects the SR overestimations, and deviations from the true random rate are of the order of 1% or less. In addition, in the case of conventional energy window STi results reproduce ST results and therefore the former can be used to obtain the true random rate.  
  Address [Oliver, Josep F.; Rafecas, Magdalena] Univ Valencia, CSIC, Inst Fis Corpuscular, IFIC, E-46003 Valencia, Spain, Email: josep.f.oliver@uv.es  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-9155 ISBN Medium  
  Area Expedition Conference  
  Notes (up) ISI:000283789700025 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ elepoucu @ Serial 344  
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Author Fernandes, L.M.P.; Freitas, E.D.C.; Ball, M.; Gomez-Cadenas, J.J.; Monteiro, C.M.B.; Yahlali, N.; Nygren, D.; dos Santos, J.M.F. url  doi
openurl 
  Title Primary and secondary scintillation measurements in a Xenon Gas Proportional Scintillation Counter Type Journal Article
  Year 2010 Publication Journal of Instrumentation Abbreviated Journal J. Instrum.  
  Volume 5 Issue Pages P09006 - 15pp  
  Keywords Interaction of radiation with matter; Gaseous detectors; Photon detectors for UV, visible and IR photons (vacuum) (photomultipliers, HPDs, others)  
  Abstract NEXT is a new experiment to search for neutrinoless double beta decay using a 100 kg radio-pure high-pressure gaseous xenon TPC. The detector requires excellent energy resolution, which can be achieved in a Xe TPC with electroluminescence readout. Hamamatsu R8520-06SEL photomultipliers are good candidates for the scintillation readout. The performance of this photomultiplier, used as VUV photosensor in a gas proportional scintillation counter, was investigated. Initial results for the detection of primary and secondary scintillation produced as a result of the interaction of 5.9 keV X-rays in gaseous xenon, at room temperature and at pressures up to 3 bar, are presented. An energy resolution of 8.0% was obtained for secondary scintillation produced by 5.9 keV X-rays. No significant variation of the primary scintillation was observed for different pressures (1, 2 and 3 bar) and for electric fields up to 0.8 V cm(-1) torr(-1) in the drift region, demonstrating negligible recombination luminescence. A primary scintillation yield of 81 +/- 7 photons was obtained for 5.9 keV X-rays, corresponding to a mean energy of 72 +/- 6 eV to produce a primary scintillation photon in xenon.  
  Address [Fernandes, L. M. P.; Freitas, E. D. C.; Monteiro, C. M. B.; dos Santos, J. M. F.] Univ Coimbra, Dept Phys, Instrumentat Ctr, P-3004516 Coimbra, Portugal, Email: pancho@gian.fis.uc.pt  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1748-0221 ISBN Medium  
  Area Expedition Conference  
  Notes (up) ISI:000283796100003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 255  
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