Sarkar, S., Sun, B. X., Oset, E., & Vicente Vacas, M. J. (2010). Dynamically generated resonances from the vector octet-baryon decuplet interaction. Eur. Phys. J. A, 44(3), 431–443.
Abstract: We study the interaction of the octet of vector mesons with the decuplet of baryons using Lagrangians of the hidden gauge theory for vector interactions. The unitary amplitudes in coupled channels develop poles that can be associated with some known baryonic resonances, while there are predictions for new ones at the energy frontier of the experimental research. The work offers guidelines on how to search for these resonances.
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Oset, E., & Ramos, A. (2010). Dynamically generated resonances from the vector octet-baryon octet interaction. Eur. Phys. J. A, 44(3), 445–454.
Abstract: We study the interaction of vector mesons with the octet of stable baryons in the framework of the local hidden gauge formalism using a coupled-channels unitary approach. We examine the scattering amplitudes and their poles, which can be associated to known J(P) = 1/2(-), 3/2(-) baryon resonances, in some cases, or give predictions in other ones. The formalism employed produces doublets of degenerate J(P) = 1/2(-), 3/2(-) states, a pattern which is observed experimentally in several cases. The findings of this work should also be useful to guide present experimental programs searching for new resonances, in particular in the strange sector where the current information is very poor.
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Liang, W. H., Molina, R., & Oset, E. (2010). Radiative open charm decay of the Y(3940), Z(3930), X(4160) resonances. Eur. Phys. J. A, 44(3), 479–486.
Abstract: We determine the radiative decay amplitudes for the decay into D* and (D) over bar gamma, or (D) over bar gamma(s)* and s. of some of the charmonium- like states classified as X, Y, Z resonances, plus some other hidden charm states which are dynamically generated from the interaction of vector mesons with charm. The mass distributions as a function of the (D) over bar gamma or (D) over bar (s)gamma. invariant mass show a peculiar behavior as a consequence of the D* (D) over bar gamma* nature of these states. The experimental search of these magnitudes can shed light on the nature of these states.
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Studen, A., Burdette, D., Chesi, E., Cindro, V., Clinthorne, N. H., Cochran, E., et al. (2010). Timing performance of the silicon PET insert probe. Radiat. Prot. Dosim., 139(1-3), 199–203.
Abstract: Simulation indicates that PET image could be improved by upgrading a conventional ring with a probe placed close to the imaged object. In this paper, timing issues related to a PET probe using high-resistivity silicon as a detector material are addressed. The final probe will consist of several (four to eight) 1-mm thick layers of silicon detectors, segmented into 1 x 1 mm(2) pads, each pad equivalent to an independent p + nn+ diode. A proper matching of events in silicon with events of the external ring can be achieved with a good timing resolution. To estimate the timing performance, measurements were performed on a simplified model probe, consisting of a single 1-mm thick detector with 256 square pads (1.4 mm side), coupled with two VATAGP7s, application-specific integrated circuits. The detector material and electronics are the same that will be used for the final probe. The model was exposed to 511 keV annihilation photons from an Na-22 source, and a scintillator (LYSO)-PMT assembly was used as a timing reference. Results were compared with the simulation, consisting of four parts: (i) GEANT4 implemented realistic tracking of electrons excited by annihilation photon interactions in silicon, (ii) calculation of propagation of secondary ionisation (electron-hole pairs) in the sensor, (iii) estimation of the shape of the current pulse induced on surface electrodes and (iv) simulation of the first electronics stage. A very good agreement between the simulation and the measurements were found. Both indicate reliable performance of the final probe at timing windows down to 20 ns.
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Hoeschen, C., Mattsson, S., Cantone, M. C., Mikuz, M., Lacasta, C., Ebel, G., et al. (2010). Minimising activity and dose with enhanced image quality by radiopharmaceutical administrations. Radiat. Prot. Dosim., 139(1-3), 250–253.
Abstract: Owing to the introduction of new diagnostic procedures, such as computed tomography (CT), positron emission tomography (PET) and single photon emission computed tomography (SPECT), the individual dose caused by medical exposures has grown rapidly in the last years. This is especially a subject to radiation protection for nuclear medical diagnosis, since in this case radiopharmaceuticals are administered to the patient, meaning not only a radiation exposure to the diseased tissue but also to the healthy tissues of large parts of the body. 'Minimizing Activity and Dose with Enhanced Image quality by Radiopharmaceutical Administrations' (MADEIRA) is a project cofunded by the European Commission within the Seventh Euratom Framework Programme that aims to improve three-dimensional (3D) nuclear medical imaging technologies significantly. MADEIRA is aiming to improve the efficacy and safety of 3D PET and SPECT functional imaging by optimising the spatial resolution and the signal-to-noise ratio, improving the knowledge of the temporal variation of the radiopharmaceuticals' uptake in and clearance from tumourous and healthy tissues, and evaluation of the corresponding patient dose. Using an optimised imaging procedure that improves the information gained per unit administered dose, MADEIRA aims especially to reduce the dose to healthy tissues of the patient. In this paper, an overall summary of the current achievements will be presented.
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BABAR Collaboration(del Amo Sanchez, P. et al), Azzolini, V., Lopez-March, N., Martinez-Vidal, F., Milanes, D. A., & Oyanguren, A. (2010). Test of Lepton Universality in Y(1S) Decays at BABAR. Phys. Rev. Lett., 104(19), 191801–7pp.
Abstract: The ratio R-tau mu(Y(1S)) = Gamma Y(1S)->tau(+)tau(-)/Gamma(+)(-)(Y(1S)->mu)(mu) is measured using a sample of (121.8 +/- 1.2) x 10(6)Y(3S) events recorded by the BABAR detector. This measurement is intended as a test of lepton universality and as a search for a possible light pseudoscalar Higgs boson. In the standard model (SM) this ratio is expected to be close to 1. Any significant deviations would violate lepton universality and could be introduced by the coupling to a light pseudoscalar Higgs boson. The analysis studies the decays Y(3S) -> Y(1S)pi(+)pi(-), Y(1S) -> l(+)l(-), where l = mu, tau. The result, R-tau μ(Y(1S)) = 1.005 +/- 0.013(stat) +/- 0.022(syst), shows no deviation from the expected SM value, while improving the precision with respect to previous measurements.
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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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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Dalitz plot analysis of D-s(+) -> K+ K- pi(+). Phys. Rev. D, 83(5), 052001–20pp.
Abstract: We perform a Dalitz plot analysis of about 100 000 D-s(+) decays to K+ K- pi(+) and measure the complex amplitudes of the intermediate resonances which contribute to this decay mode. We also measure the relative branching fractions of D-s(+) -> K+ K+ pi(-) and D-s(+) -> K+ K+ K-. For this analysis we use a 384 fb(-1) data sample, recorded by the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider running at center-of-mass energies near 10.58 GeV.
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Chang, Q., Li, X. Q., & Yang, Y. D. (2011). The effects of a family nonuniversal Z ' boson on B -> pi pi decays. Int. J. Mod. Phys. A, 26(7-8), 1273–1294.
Abstract: Motivated by the measured large branching ratio of (B) over bar (0) --> pi(0)pi(0) (the so-called pi pi puzzle), we investigate the effects of a family nonuniversal Z' model on the tree-dominated B --> pi pi decays. We find that the Z' coupling parameter zeta(LR)(d) similar to 0.05 with a nontrivial new weak phase phi(L)(d) similar to -50 degrees, which is relevant to the Z' contributions to the QCD penguin sector Delta C-5, is needed to reconcile the observed discrepancy. Combined with the recent fitting results from B --> pi K, pi K* and rho K decays, the Z' parameter spaces are severely reduced but still not excluded entirely, implying that both the “pi pi” and “pi K” puzzles could be accommodated simultaneously within such a family nonuniversal Z' model.
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Catford, W. N. et al, Caballero, L., & Rubio, B. (2010). Migration of Nuclear Shell Gaps Studied in the d(Ne-24, p gamma)Ne-25 Reaction. Phys. Rev. Lett., 104(19), 192501–4pp.
Abstract: The transfer of neutrons onto Ne-24 has been measured using a reaccelerated radioactive beam of Ne-24 to study the (d, p) reaction in inverse kinematics. The unusual raising of the first 3/2(+) level in Ne-25 and its significance in terms of the migration of the neutron magic number from N = 20 to N = 16 is put on a firm footing by confirmation of this state's identity. The raised 3/2(+) level is observed simultaneously with the intruder negative parity 7/2(-) and 3/2(-) levels, providing evidence for the reduction in the N = 20 gap. The coincident gamma-ray decays allowed the assignment of spins as well as the transferred orbital angular momentum. The excitation energy of the 3/2(+) state shows that the established USD shell model breaks down well within the sd model space and requires a revised treatment of the proton-neutron monopole interaction.
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