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ATLAS Collaboration(Aaboud, M. et al), Alvarez Piqueras, D., Barranco Navarro, L., Cabrera Urban, S., Castillo Gimenez, V., Cerda Alberich, L., et al. (2017). Precision measurement and interpretation of inclusive W+, W- and Z/gamma* production cross sections with the ATLAS detector. Eur. Phys. J. C, 77(6), 367–62pp.
Abstract: High-precision measurements by the ATLAS Collaboration are presented of inclusive W+ -> l(+) nu, W- -> l(-) (nu) over bar and Z/gamma* -> ll (l = e, mu) Drell-Yan production cross sections at the LHC. The data were collected in proton-proton collisions at root s = 7 TeV with an integrated luminosity of 4.6 fb(-1). Differential W+ and W- cross sections are measured in a lepton pseudorapidity range vertical bar eta(l)vertical bar < 2.5. Differential Z/gamma* cross sections are measured as a function of the absolute dilepton rapidity, for vertical bar y(ll)vertical bar < 3.6, for three intervals of dilepton mass, m(ll), extending from 46 to 150 GeV. The integrated and differential electron- and muon-channel cross sections are combined and compared to theoretical predictions using recent sets of parton distribution functions. The data, together with the final inclusive e(+/-) p scattering cross-section data from H1 and ZEUS, are interpreted in a next-to-next-to-leading-order QCD analysis, and a new set of parton distribution functions, ATLAS-epWZ16, is obtained. The ratio of strange-to-light sea-quark densities in the proton is determined more accurately than in previous determinations based on collider data only, and is established to be close to unity in the sensitivity range of the data. A new measurement of the CKM matrix element vertical bar V-cs vertical bar is also provided.
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., Ruiz Valls, P., et al. (2017). Measurement of the J/psi pair production cross-section in pp collisions at root s=13 TeV. J. High Energy Phys., 06(6), 047–38pp.
Abstract: The production cross-section of J/psi pairs is measured using a data sample of pp collisions collected by the LHCb experiment at a centre-of-mass energy of root s = 13TeV, corresponding to an integrated luminosity of 279 +/- 11 pb(-1). The measurement is performed for J/psi mesons with a transverse momentum of less than 10 GeV/c in the rapidity range 2.0 < y < 4.5. The production cross-section is measured to be 15.2 +/- 1.0 +/- 0.9 nb. The first uncertainty is statistical, and the second is systematic. The differential cross-sections as functions of several kinematic variables of the J/psi pair are measured and compared to theoretical predictions.
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ATLAS Collaboration(Aaboud, M. et al), Alvarez Piqueras, D., Barranco Navarro, L., Cabrera Urban, S., Castillo Gimenez, V., Cerda Alberich, L., et al. (2017). Measurements of the production cross section of a Z boson in association with jets in pp collisions at root s=13 TeV with the ATLAS detector. Eur. Phys. J. C, 77(6), 361–31pp.
Abstract: Measurements of the production cross section of a Z boson in association with jets in proton-proton collisions at root s = 13TeV are presented, using data corresponding to an integrated luminosity of 3.16 fb(-1) collected by the ATLAS experiment at the CERN Large Hadron Collider in 2015. Inclusive and differential cross sections are measured for events containing a Z boson decaying to electrons or muons and produced in association with up to seven jets with p(T) > 30GeV and vertical bar y vertical bar < 2.5. Predictions from different Monte Carlo generators based on leading-order and nextto-leading-order matrix elements for up to two additional partons interfaced with parton shower and fixed-order predictions at next-to-leading order and next-to-next-to-leading order are compared with the measured cross sections. Good agreement within the uncertainties is observed for most of the modelled quantities, in particular with the generators which use next-to-leading-order matrix elements and the more recent next-to-next-to-leading-order fixed-order predictions.
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Menchon, C. C., Olmo, G. J., & Rubiera-Garcia, D. (2017). Nonsingular black holes, wormholes, and de Sitter cores from anisotropic fluids. Phys. Rev. D, 96(10), 104028–16pp.
Abstract: We study Born-Infeld gravity coupled to an anisotropic fluid in a static, spherically symmetric background. The free function characterizing the fluid is selected on the following grounds: i) recovery of the Reissner-Nordstrom solution of General Relativity at large distances, ii) fulfillment of classical energy conditions, and iii) inclusion of models of nonlinear electrodynamics as particular examples. Four branches of solutions are obtained, depending on the signs of two parameters on the gravity and matter sectors. On each branch, we discuss in detail the modifications on the innermost region of the corresponding solutions, which provides a plethora of configurations, including nonsingular black holes and naked objects, wormholes, and de Sitter cores. The regular character of these configurations is discussed according to the completeness of geodesics and the behavior of curvature scalars.
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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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