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Author (up) Rodriguez-Alvarez, M.J.; Sanchez, F.; Soriano, A.; Iborra, A.; Mora, C.
Title Exploiting symmetries for weight matrix design in CT imaging Type Journal Article
Year 2011 Publication Mathematical and Computer Modelling Abbreviated Journal Math. Comput. Model.
Volume 54 Issue 7-8 Pages 1655-1664
Keywords Computerized tomography imaging; Polar grid; System matrix; Rotation symmetries; ART
Abstract In this paper we propose several methods of constructing the system matrix (SM) of a Computed Tomography (CT) scanner with two objectives: (1) to construct SMs in the shortest possible time and store them in an ordinary PC without losing quality, (2) to analyze the possible applications of the proposed method to 3D, taking into account SMs' sizes, computing time and reconstructed image quality. In order to build the SM, we propose two new field of view (FOV) pixellation schemes, based on a polar coordinate system (polar grid) by taking advantage of the polar rotation symmetries of CT devices. Comparisons between the SMs proposed are performed using two phantom and a real CT-simulator images. Global error, contrast, noise and homogeneity of the reconstructed images are discussed.
Address [Rodriguez-Alvarez, MJ; Iborra, A; Mora, C] Univ Politecn Valencia, Inst Matemat Multidisciplinar, Valencia 46022, Spain, Email: mjrodri@imm.upv.es
Corporate Author Thesis
Publisher Pergamon-Elsevier Science Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0895-7177 ISBN Medium
Area Expedition Conference
Notes WOS:000293269200007 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ elepoucu @ Serial 708
Permanent link to this record
 
 
Author (up) Roszkowski, L.; Ruiz de Austri, R.; Trotta, R.; Tsai, Y.L.S.; Varley, T.A.
Title Global fits of the nonuniversal Higgs model Type Journal Article
Year 2011 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 83 Issue 1 Pages 015014 - 19pp
Keywords
Abstract We carry out global fits to the nonuniversal Higgs Model (NUHM), applying all relevant present-day constraints. We present global probability maps for the NUHM parameters and observables (including collider signatures, direct, and indirect detection quantities), both in terms of posterior probabilities and in terms of profile likelihood maps. We identify regions of the parameter space where the neutralino dark matter in the model is either binolike, or else higgsinolike with mass close to 1 TeV and a spin-independent scattering cross section similar to 10(-9)-10(-8) pb. We trace the occurrence of the higgsinolike region to be a consequence of a mild focusing effect in the running of one of the Higgs masses, the existence of which in the NUHM we identify in our analysis. Although the usual binolike neutralino is more prominent, higgsinolike dark matter cannot be excluded, however its significance strongly depends on the prior and statistics used to assess it. We note that, despite experimental constraints often favoring different regions of parameter space to the constrained minimal supersymmetric standard model, most observational consequences appear fairly similar, which will make it challenging to distinguish the two models experimentally.
Address [Roszkowski, Leszek; Tsai, Yue-Lin Sming; Varley, Tom A.] Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, S Yorkshire, England, Email: L.Roszkowski@sheffield.ac.uk
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 ISI:000286765800007 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 586
Permanent link to this record
 
 
Author (up) Sajjad Athar, M.; Ruiz Simo, I.; Vicente Vacas, M.J.
Title Nuclear medium modification of the F2(x, Q^2) structure function Type Journal Article
Year 2011 Publication Nuclear Physics A Abbreviated Journal Nucl. Phys. A
Volume 857 Issue 1 Pages 29-41
Keywords Structure function; Nuclear medium effects; Deep inelastic scattering; Local density approximation
Abstract We study the nuclear effects in the electromagnetic structure function F-2(x, Q(2)) in the deep inelastic lepton nucleus scattering process by taking into account Fermi motion, binding, pion and rho meson cloud contributions. Calculations have been done in a local density approximation using relativistic nuclear spectral functions which include nucleon correlations. The ratios R-F2(A) (x, Q(2)) = 2F(2)(A)(x, Q(2))/AF(2)(D)(x, Q(2)) are obtained and compared with recent JLab results for light nuclei with special attention to the slope of the x distributions. This magnitude shows a non-trivial A dependence and it is insensitive to possible normalization uncertainties. The results have also been compared with some of the older experiments using intermediate mass nuclei.
Address [Athar, M. Sajjad] Aligarh Muslim Univ, Dept Phys, Aligarh 202002, Uttar Pradesh, India, Email: sajathar@gmail.com
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0375-9474 ISBN Medium
Area Expedition Conference
Notes ISI:000290607500004 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 627
Permanent link to this record
 
 
Author (up) Schwetz, T.; Tortola, M.; Valle, J.W.F.
Title Global neutrino data and recent reactor fluxes: the status of three-flavour oscillation parameters Type Journal Article
Year 2011 Publication New Journal of Physics Abbreviated Journal New J. Phys.
Volume 13 Issue Pages 063004 - 15pp
Keywords
Abstract We present the results of a global neutrino oscillation data analysis within the three-flavour framework. We include the latest results from the MINOS long-baseline experiment (including electron neutrino appearance and anti-neutrino data), updating all relevant solar (Super-Kamiokande (SK) II + III), atmospheric (SK I + II + III) and reactor (KamLAND) data. Furthermore, we include a recent re-calculation of the anti-neutrino fluxes emitted from nuclear reactors. These results have important consequences for the analysis of reactor experiments and in particular for the status of the mixing angle theta(13). In our recommended default analysis, we find from the global fit that the hint for nonzero theta(13) remains weak, at 1.8 sigma for both neutrino mass hierarchy schemes. However, we discuss in detail the dependence of these results on assumptions regarding the reactor neutrino analysis.
Address [Schwetz, Thomas] Max Planck Inst Kernphys, D-69029 Heidelberg, Germany, Email: schwetz@mpi-hd.mpg.de
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 1367-2630 ISBN Medium
Area Expedition Conference
Notes ISI:000292137500004 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 666
Permanent link to this record
 
 
Author (up) Schwetz, T.; Tortola, M.; Valle, J.W.F.
Title Where we are on theta(13): addendum to 'Global neutrino data and recent reactor fluxes: status of three-flavor oscillation parameters' Type Journal Article
Year 2011 Publication New Journal of Physics Abbreviated Journal New J. Phys.
Volume 13 Issue Pages 109401 - 5pp
Keywords
Abstract In this addendum to Schwetz et al (2011 New J. Phys. 13 063004), we consider the recent results from long-baseline nu(mu) -> nu(e) searches at the Tokai to Kamioka (T2K) and Main Injector Neutrino Oscillation Search (MINOS) experiments and investigate their implications for the mixing angle theta(13) and the leptonic Dirac CP phase delta. By combining the 2.5 sigma indication for a nonzero value of theta(13) coming from the T2K data with global neutrino oscillation data, we obtain a significance for theta(13) > 0 of about 3 sigma with best fit points sin(2) theta(13) = 0.013 (0.016) for normal (inverted) neutrino mass ordering. These results depend somewhat on assumptions concerning the analysis of reactor neutrino data.
Address [Schwetz, T] Max Planck Inst Kernphys, D-69029 Heidelberg, Germany, Email: schwetz@mpi-hd.mpg.de
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 1367-2630 ISBN Medium
Area Expedition Conference
Notes WOS:000296664700001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 801
Permanent link to this record
 
 
Author (up) SciBooNE Collaboration (Cheng, G. et al); Catala-Perez, J.; Gomez-Cadenas, J.J.; Sorel, M.
Title Measurement of K(+) production cross section by 8 GeV protons using high-energy neutrino interactions in the SciBooNE detector Type Journal Article
Year 2011 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 84 Issue 1 Pages 012009 - 22pp
Keywords
Abstract The SciBooNE Collaboration reports K(+) production cross section and rate measurements using high-energy daughter muon neutrino scattering data off the SciBar polystyrene (C(8)H(8)) target in the SciBooNE detector. The K(+) mesons are produced by 8 GeV protons striking a beryllium target in Fermilab Booster Neutrino Beam line (BNB). Using observed neutrino and antineutrino events in SciBooNE, we measure d(2)sigma/dpd Omega = (5.34 +/- 0.76) mb/(GeV/c x sr) for p + Be -> K(+) + X at mean K(+) energy of 3.9 GeVand angle (with respect to the proton beam direction) of 3.7 degrees, corresponding to the selected K(+) sample. Compared to Monte Carlo predictions using previous higher energy K(+) production measurements, this measurement, which uses the NUANCE neutrino interaction generator, is consistent with a normalization factor of 0.85 +/- 0.12. This agreement is evidence that the extrapolation of the higher energy K(+) measurements to an 8 GeV beam energy using Feynman scaling is valid. This measurement reduces the error on the K(+) production cross section from 40% to 14%.
Address [Cheng, G; Mariani, C; Djurcic, Z; Franke, AJ; Mahn, KBM; Shaevitz, MH] Columbia Univ, Dept Phys, New York, NY 10027 USA
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 WOS:000293248600001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 709
Permanent link to this record
 
 
Author (up) SciBooNE Collaboration (Nakajima, Y. et al); Catala-Perez, J.; Gomez-Cadenas, J.J.; Sorel, M.
Title Measurement of inclusive charged current interactions on carbon in a few-GeV neutrino beam Type Journal Article
Year 2011 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 83 Issue 1 Pages 012005 - 21pp
Keywords
Abstract We report a measurement of inclusive charged current interactions of muon neutrinos on carbon with an average energy of 0.8 GeV using the Fermilab Booster Neutrino Beam. We compare our measurement with two neutrino interaction simulations: NEUT and NUANCE. The charged current interaction rates (product of flux and cross section) are extracted by fitting the muon kinematics, with a precision of 6%-15% for the energy dependent and 3% for the energy integrated analyses. We also extract charged current inclusive interaction cross sections from the observed rates, with a precision of 10%-30% for the energy dependent and 8% for the energy integrated analyses. This is the first measurement of the charged current inclusive cross section on carbon around 1 GeV. These results can be used to convert previous SciBooNE cross-section ratio measurements to absolute cross-section values.
Address [Nakajima, Y.; Hiraide, K.; Kubo, H.; Kurimoto, Y.; Matsuoka, K.; Nakaya, T.; Orme, D.; Otani, M.; Yokoyama, M.] Kyoto Univ, Dept Phys, Kyoto 6068502, Japan
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 ISI:000286766000001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 562
Permanent link to this record
 
 
Author (up) Semikoz, V.B.; Valle, J.W.F.
Title Chern-Simons anomaly as polarization effect Type Journal Article
Year 2011 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 11 Issue 11 Pages 048
Keywords
Abstract The parity violating, Chern-Simons term in the epoch before the electroweak phase transition can be interpreted as a polarization effect associated to massless right-handed electrons (positrons) in the presence of a large-scale seed hypermagnetic field. We reconfirm the viability of a unified seed field scenario relating the cosmological baryon asymmetry and the origin of the protogalactic large-scale magnetic fields observed in astronomy.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language 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 WOS:000298141300048 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 866
Permanent link to this record
 
 
Author (up) Serenelli, A.M.; Haxton, W.C.; Pena-Garay, C.
Title Solar Models With Accretion. I. Application To The Solar Abundance Problem Type Journal Article
Year 2011 Publication Astrophysical Journal Abbreviated Journal Astrophys. J.
Volume 743 Issue 1 Pages 24 - 20pp
Keywords accretion, accretion disks; neutrinos; Sun: abundances; Sun: helioseismology; Sun: interior
Abstract We generate new standard solar models using newly analyzed nuclear fusion cross sections and present results for helioseismic quantities and solar neutrino fluxes. The status of the solar abundance problem is discussed. We investigate whether nonstandard solar models with accretion from the protoplanetary disk might alleviate this problem. We examine a broad range of models, analyzing metal-enriched and metal-depleted accretion and three scenarios for the timing of accretion. Only partial solutions are found. Formetal-rich accreted material (Z(ac) greater than or similar to 0.018) there exist combinations of accreted mass and metallicity that bring the depth of the convective zone into agreement with the helioseismic value. For the surface helium abundance, the helioseismic value is reproduced if metal-poor or metal-free accretion is assumed (Z(ac) less than or similar to 0.09). In both cases a few percent of the solar mass must be accreted. Precise values depend on when accretion takes place. We do not find a simultaneous solution to both problems but speculate that changing the hydrogen-to-helium mass ratio in the accreted material may lead to more satisfactory solutions. We also show that, with current data, solar neutrinos are already a very competitive source of information about the solar core and can help constraining possible accretion histories. Even without helioseismic constraints, solar neutrinos rule out the possibility that more than 0.02 M(circle dot) from the protoplanetary disk were accreted after the Sun settled on the main sequence. Finally, we discuss how measurements of neutrinos from the CN cycle could shed light on the interaction between the early Sun and its protoplanetary disk.
Address [Serenelli, Aldo M.] Fac Ciencias, CSIC IEEC, Inst Ciencias Espacio, Bellaterra 08193, Spain
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 0004-637x ISBN Medium
Area Expedition Conference
Notes WOS:000297408300024 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 857
Permanent link to this record
 
 
Author (up) Soriano, A.; Gonzalez, A.; Orero, A.; Moliner, L.; Carles, M.; Sanchez, F.; Benlloch, J.M.; Correcher, C.; Carrilero, V.; Seimetz, M.
Title Attenuation correction without transmission scan for the MAMMI breast PET Type Journal Article
Year 2011 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 648 Issue Pages S75-S78
Keywords Breast PET; Attenuation correction
Abstract Whole-body Positron Emission Tomography (PET) scanners are required in order to span large Fields of View (FOV). Therefore, reaching the sensitivity and spatial resolution required for early stage breast tumor detection is not straightforward. MAMMI is a dedicated breast PET scanner with a ring geometry designed to provide PET images with a spatial resolution as high as 1.5 mm, being able to detect small breast tumors ( < 1 cm). The patient lays down in prone position during the scan, thus making possible to image the whole breast, up to regions close to the base of the pectoral without the requirement of breast compression. Attenuation correction (AC) for PET data improves the image quality and the quantitative accuracy of radioactivity distribution determination. In dedicated, high resolution breast cancer scanners, this correction would enhance the proper diagnosis in early disease stages. In whole-body PET scanners, AC is usually taken into account with the use of transmission scans, either by external radioactive rod sources or by Computed Tomography (CT). This considerably increases the radiation dose administered to the patient and time needed for the exploration. In this work we propose a method for breast shape identification by means of PET image segmentation. The breast shape identification will be used for the determination of the AC. For the case of a specific breast PET scanner the procedure we propose should provide AC similar to that obtained by transmission scans as we take advantage of the breast anatomical simplicity. Experimental validation of the proposed approach with a dedicated breast PET prototype is also presented. The main advantage of this method is an important dose reduction since the transmission scan is not required.
Address [Soriano, A.; Orero, A.; Moliner, L.; Carles, M.; Sanchez, F.; Benlloch, J. M.] Univ Valencia, CSIC, Inst Fis Corpuscular, E-46980 Paterna, Spain, Email: soriano@ific.uv.es
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000305376900021 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 1069
Permanent link to this record