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Ortega, P. G., Entem, D. R., & Fernandez, F. (2017). LHCb pentaquarks in constituent quark models. Phys. Lett. B, 764, 207–211.
Abstract: The recently discovered P-c(4380)(+) and P-c(4450)(+) states at LHCb have masses close to the (D) over bar Sigma(C)* and (D) over bar*Sigma(C) thresholds, respectively, which suggest that they may have significant meson-baryon molecular components. We analyze these states in the framework of a constituent quark model which has been applied to a wide range of hadronic observables, being the model parameters, therefore, completely constrained. The P-c(4380)(+) and P-c(4450)(+) are studied as molecular states composed by charmed baryons and open charm mesons. Several bound states with the proper binding energy are found in the (D) over bar Sigma(C)* and (D) over bar*Sigma(C) chennels. We discuss the possible assignments of these states from their decay widths. Moreover, two more states are predicted, associated with the (D) over bar Sigma(C) and (D) over bar*Sigma*(C) thresholds. (C) 2016 Published by Elsevier B.V.
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Sepehri, A., Pincak, R., & Olmo, G. J. (2017). M-theory, graphene-branes and superconducting wormholes. Int. J. Geom. Methods Mod. Phys., 14(11), 1750167–32pp.
Abstract: Exploiting an M-brane system whose structure and symmetries are inspired by those of graphene (what we call a graphene-brane), we propose here a similitude between two layers of graphene joined by a nanotube and wormholes scenarios in the brane world. By using the symmetries and mathematical properties of the M-brane system, we show here how to possibly increase its conductivity, to the point of making it as a superconductor. The questions of whether and under which condition this might point to the corresponding real graphene structures becoming superconducting are briefly outlined.
Keywords: M-theory; wormholes; graphene; superconductors
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Bayar, M., & Debastiani, V. R. (2017). a(0)(980) – f(0)(980) mixing in chi(c1) -> pi(0)f(0)(980) -> pi(0)pi(+)pi(-) and chi(c1) -> pi(0) a(0)(980) -> pi(0)pi(0)eta. Phys. Lett. B, 775, 94–99.
Abstract: We study the isospin breaking in the reactions chi(c1) -> pi(0)pi(+)pi(-) and chi(c1) -> pi(0)pi(0)eta and its relation to the a(0)(980) – f(0)(980) mixing, which was measured by the BESIII Collaboration. We show that the same theoretical model previously developed to study the chi(c1) -> eta pi(+)pi(-) reaction (also measured by BESIII), and further explored in the predictions to the eta(c) -> eta pi(+)pi(-), can be successfully employed in the present study. We assume that the chi(c1) behaves as an SU(3) singlet to find the weight in which trios of pseudoscalars are created, followed by the final state interaction of pairs of mesons to describe how the a(0)(980) and f(0)(980) are dynamically generated, using the chiral unitary approach in coupled channels. The isospin violation is introduced through the use of different masses for the charged and neutral kaons, either in the propagators of pairs of mesons created in the chi(c1) decay, or in the propagators inside the T matrix, constructed through the unitarization of the scattering and transition amplitudes of pairs of pseudoscalar mesons. We find that violating isospin inside the T matrix makes the pi(0)eta -> pi(+)pi(-) amplitude nonzero, which gives an important contribution and also enhances the effect of the K (K) over bar term. We also find that the most important effect in the total amplitude is the isospin breaking inside the T matrix, due to the constructive sum of pi(0)eta -> pi(+)pi(-) and K (K) over bar -> pi(+)pi(-), which is essential to get a good agreement with the experimental measurement of the mixing.
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Jungclaus, A. et al, Gadea, A., & Montaner-Piza, A. (2017). Observation of a gamma-decaying millisecond isomeric state in Cd-128(80). Phys. Lett. B, 772, 483–488.
Abstract: A new high-spin isomer in the neutron-rich nucleus Cd-128 was populated in the projectile fission of a U-238 beam at the Radioactive Isotope Beam Factory at RIKEN. A half-life of T-1/2 = 6.3(8) mswas measured for the new state which was tentatively assigned a spin/parity of (15(-)). The experimental results are compared to shell model calculations performed using state-of-the-art realistic effective interactions and to the neighbouring nucleus Cd-129. In the present experiment no evidence was found for the decay of a 18(+) E6 spin-trap isomer, based on the complete alignment of the two-neutron and two-proton holes in the 0h(11/2) and the 0g(9/2) orbit, respectively, which is predicted to exist by the shell model. (C) 2017 The Author(s). Published by Elsevier B.V.
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Ma, Y. Z., Vijande, J., Ballester, F., Tedgren, A. C., Granero, D., Haworth, A., et al. (2017). A generic TG-186 shielded applicator for commissioning model-based dose calculation algorithms for high-dose-rate Ir-192 brachytherapy. Med. Phys., 44(11), 5961–5976.
Abstract: PurposeA joint working group was created by the American Association of Physicists in Medicine (AAPM), the European Society for Radiotherapy and Oncology (ESTRO), and the Australasian Brachytherapy Group (ABG) with the charge, among others, to develop a set of well-defined test case plans and perform calculations and comparisons with model-based dose calculation algorithms (MBDCAs). Its main goal is to facilitate a smooth transition from the AAPM Task Group No. 43 (TG-43) dose calculation formalism, widely being used in clinical practice for brachytherapy, to the one proposed by Task Group No. 186 (TG-186) for MBDCAs. To do so, in this work a hypothetical, generic high-dose rate (HDR) Ir-192 shielded applicator has been designed and benchmarked. MethodsA generic HDR Ir-192 shielded applicator was designed based on three commercially available gynecological applicators as well as a virtual cubic water phantom that can be imported into any DICOM-RT compatible treatment planning system (TPS). The absorbed dose distribution around the applicator with the TG-186 Ir-192 source located at one dwell position at its center was computed using two commercial TPSs incorporating MBDCAs (Oncentra((R)) Brachy with Advanced Collapsed-cone Engine, ACE, and BrachyVision ACUROS) and state-of-the-art Monte Carlo (MC) codes, including ALGEBRA, BrachyDose, egs_brachy, Geant4, MCNP6, and Penelope2008. TPS-based volumetric dose distributions for the previously reported source centered in water and source displaced test cases, and the new source centered in applicator test case, were analyzed here using the MCNP6 dose distribution as a reference. Volumetric dose comparisons of TPS results against results for the other MC codes were also performed. Distributions of local and global dose difference ratios are reported. ResultsThe local dose differences among MC codes are comparable to the statistical uncertainties of the reference datasets for the source centered in water and source displaced test cases and for the clinically relevant part of the unshielded volume in the source centered in applicator case. Larger local differences appear in the shielded volume or at large distances. Considering clinically relevant regions, global dose differences are smaller than the local ones. The most disadvantageous case for the MBDCAs is the one including the shielded applicator. In this case, ACUROS agrees with MC within [-4.2%, +4.2%] for the majority of voxels (95%) while presenting dose differences within [-0.12%, +0.12%] of the dose at a clinically relevant reference point. For ACE, 95% of the total volume presents differences with respect to MC in the range [-1.7%, +0.4%] of the dose at the reference point. ConclusionsThe combination of the generic source and generic shielded applicator, together with the previously developed test cases and reference datasets (available in the Brachytherapy Source Registry), lay a solid foundation in supporting uniform commissioning procedures and direct comparisons among treatment planning systems for HDR Ir-192 brachytherapy.
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