545 research outputs found
Position-resolved charge collection of silicon carbide detectors with an epitaxially-grown graphene layer
No full textAbstract Silicon carbide (SiC) has outstanding physical properties therefore, diodes based on SiC are being considered for many radiation detection applications such as particle accelerator experiments and medical dosimetry. Moreover, by reducing the metal on the surface of the diode there is the potential to enhance its performance in some fields where the presence of metal is detrimental. To this end, SiC detectors with an epitaxially-grown graphene layer (EG), that substitutes the metallic contact, in the sensitive region were produced at IMB-CNM, profiting from the conductivity of the mono-atomic layer material. To isolate the effect of the graphene on the charge collection, samples without graphene were produced in parallel. In this paper, the effect of EG on Silicon Carbide p-in-n radiation detectors is studied in terms of charge collection with a radioactive source and by means of the transient current technique (TCT), which allows for position-dependent signal formation analysis. As a result of the former, we show the capability of the EG-SiC sensor for charge collection after signal integration, to a resolution close to that of a sensor fully metallised. Moreover, from the TCT studies, we observe uniform charge collection across the active region, as well as an up-to ∼ 40% transient amplitude damping which, compared with the ∼ 90% on the sample containing no metallic contact, proves that the presence of graphene benefits the performance of the device and that the technology is viable for radiation detection as an alternative to metal
Analysis of the Hydrocarbon Sector in Bolivia: How are the Gas and Oil Revenues Distributed?
No full textThis report analyzes the importance of the hydrocarbon sector in Bolivia. The oil and gas sector currently represents a vital component of the Bolivian economy, accounting for 7 percent of the GDP in term of production and more than 30 percent of total government income. In addition, the hydrocarbon sector not only represents an important economic sector but also a political and social instrument for negotiations, mobilization and social participation. The hydrocarbon sector in Bolivia also plays a strategic geopolitical role in South America as it has the second largest reserves of natural gas in the region after Venezuela. However, the current Bolivian nationalization process has placed this privileged position of the country into question as Bolivia is trying to undo twenty years of neo-liberal policies with the adoption of more nationalistic policies, assuming the control of the sector and challenging the international community and the private sector to benefit its population. The report also exposes that the important hydrocarbon revenues are not evenly distributed across the country’s regions. The most important instruments of taxation, royalties and the IDH, are creating a disequilibrium implying that regions with large populations get considerably fewer resources than less populated regions. In addition, the current distribution system, which is based on political criteria with some regional notion of fairness, is discriminatory in the allocation of resources with out taking into account poverty criteria. In a poor country like Bolivia with a strong political framework on poverty alleviation, the lack of poverty criteria in the distribution system of such significant resources makes 1.5 million poor people from La Paz get fewer resources than 300 thousand poor people from Pando in terms of per capita distribution (600 dollars per capita in Pando). The report has found that the distribution system of the hydrocarbon revenues needs serious changes to be more efficient and accomplish the goal of poverty reduction. The current system of revenue allocation creates significant per capita inequalities between regions and exacerbates the regional dependency on central transfers that depends on exhaustible and unstable hydrocarbon production (92 percent of the prefecturas’ revenues and 66 percent of the municipalities’ revenues come from government transfers). In addition, the decentralization process of the country has several weaknesses. It does not allow local governments to create their own tributary policies and generate their own resources, with exception of municipalities that to some extent can administrate and collect two regional taxes defined by the central government. This disequilibrium has the potential to seriously threaten the unity of the country as a nation. This situation will encourage producing regions to push for a large degree of decentralization in order to take advantage of the enormous inflows of resources that the sector is generating. In addition, non-producing regions will push for a significant share of those large resources given the severe degree of poverty in the country. This leads to two important questions to ask; first, who owns the natural resources, producing regions or the central government, and second, how those revenues should be distributed? 3 In general, those questions are hard to answer and in most cases the answers have significant political notions. In this aspect, the report presents results of a hypothetical calculation in which we combine to some extent the notion that producing regions have the right to a share of the revenues as does the central government. Because producing regions have solid arguments to claim ownership, like natural heritage and social cost reimbursement, we found undesirable and unviable the idea of completely draining those resources from them. Nonetheless, the central government also has significant arguments to have a share of those revenues, like income stability, fiscal equilibrium and macroeconomic considerations. Therefore, we found it important that the central government should benefit from a share of the natural wealth. However, the results of the hypothetical exercise presented in this report have the objective of opening the debate and dialogue for needed changes in the Bolivian hydrocarbon distribution system rather than suggesting a definitive answer for a distribution system in Bolivia.Hydrocarbons, Tributary System, Resources Allocation, Transfer System, Bolivia
Métricas de autor Ivan Cabeza Rojas
No full textInforme de las métricas de autor del Ing. Ivan Cabeza Rojas de las publicaciones indexadas en Google Académico cuyo objetivo es entregar un insumo para el fortalecimiento de las capacidades y potencialidades de los autores de la Universidad Santo Tomás en el posicionamiento y visibilidad de sus publicaciones.Report of the author metrics Ivan Cabeza Rojas of the publications indexed in Google Scholar whose objective is to provide an input for the strengthening of the capacities and potentialities of the authors of the Santo Tomás University in the positioning and visibility of their publications.http://unidadinvestigacion.usta.edu.c
Search for dark mesons decaying to top and bottom quarks in proton-proton collisions at √s = 13 TeV with the ATLAS detector
No full text54 pages in total, author list starting page 37, 13 figures, 6
tables, published as JHEP 09 (2024) 005. All figures including auxiliary
figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2023-09/A search for dark mesons originating from strongly-coupled, dark
flavor symmetry conserving models and decaying gaugephobically to pure Standard
Model final states containing top and bottom quarks is presented. The search
targets fully hadronic final states and final states with exactly one electron
or muon and multiple jets. The analyzed data sample corresponds to an
integrated luminosity of 140 of protonproton collisions collected
at TeV with the ATLAS detector at the Large Hadron Collider. No
significant excess over the Standard Model background expectation is observed
and the results are used to set the first direct constraints on this type of
model. The two-dimensional signal space of dark pion masses and
dark rho-meson masses is scanned. For ,
dark pions with masses GeV are excluded at the 95% CL, while
for masses GeV are excluded.Peer reviewe
A search for R-parity-violating supersymmetry in fnal states containing many jets in pp collisions at √s = 13 TeV with the ATLAS detector
No full text45 pages in total, author list starting page 28, 10 figures, 6
tables, published by JHEP. All figures including auxiliary figures are
available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2019-24A search for R-parity-violating supersymmetry in fnal states with high jet
multiplicity is presented. The search uses 140 fb−1 of proton-proton collision data at √
s =
13 TeV collected by the ATLAS experiment during Run 2 of the Large Hadron Collider. The
results are interpreted in the context of R-parity-violating supersymmetry models that feature
prompt gluino-pair production decaying directly to three jets each or decaying to two jets
and a neutralino which subsequently decays promptly to three jets. No signifcant excess
over the Standard Model expectation is observed and exclusion limits at the 95% confdence
level are extracted. Gluinos with masses up to 1800 GeV are excluded when decaying directly
to three jets. In the cascade scenario, gluinos with masses up to 2340 GeV are excluded
for a neutralino with mass up to 1250 GeV.Peer reviewe
Replication data for Characterisation of SiC radiation technologies with synchrotron X-rays
No full textRaw data obtained at the ALBA synchrotron with SiC diode devices for the paper: "Characterisation of SiC radiation detector technologies with synchrotron X-rays"This work has been funded by the IMB-CNM (CSIC) internal TRIGGER project PlACeD and the laCaixa Health foundation DosiFLASH project HR23-00718. These experiments were performed at BL13-XALOC beamline at ALBA Synchrotron with the collaboration of ALBA staff. The beam time was funded by ALBA with proposal ID 2024028103.
This work has also received funding from the EMPIR programme co-financed by the Par-ticipating States and from the European Union’s Horizon 2020 research and innovation program under project 18HLT04-UHDpulse, from project NEWDOSI (PID2021-123484OB-I00), financed by MCIN / AEI / 10.13039/501100011033 / FEDER, UE and from Grant RTC-2017–6369–3 (GRACE) by MCIN/AEI/ 10.13039/ 501100011033 and ERDF ‘A way of making Europe’. Support through the Maria de Maeztu grant CEX2023-001397-M funded by
MICIU/AEI/10.13039/501100011033 is acknowledged.List of files: . Fig3-linescan-SiC-Graphene_50x50_2.dat . Fig3-linescan-SiC-Metal3um_50x50_2.dat . Fig3-LineScan_SiC-NoMetal3um_50x50_2.dat . Fig3-LineScan_SiC_metal50um_50x50.dat . Fig4-currenscan_SiC_metal50um_50x50.dat . Fig4-currentscan-SiC-Graphene_50x50_3.dat . Fig4-currentscan-SiC-Metal3um_50x50_3.dat . Fig5-Energyscan-SiC-Graphene_50x50_2.dat . Fig5-Energyscan-SiC-Metal3um_50x50_1.dat . Fig5-Energyscan-SiC-Metal3um_inRing_50x50_2.dat . Fig5-Energyscan-SiliconReference_Hamamatsu-P1_sample1_50x50_3_sorted.dat . Fig5-EnergyScan_SiC_metal50um_50x50_removed_saturated.datN
Search for decays of the Higgs boson into a pair of pseudoscalar particles decaying into Formula Presented using Formula Presented collisions at Formula Presented with the ATLAS detector
No full text52 pages in total, author list starting page 35, 10 figures, 3
tables. Published in Phys. Rev. D 110 (2024) 052013. All figures are
available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HDBS-2021-07/This paper presents a search for exotic decays of the Higgs boson into a pair
of new pseudoscalar particles, , where one pseudoscalar decays
into a -quark pair and the other decays into a -lepton pair, in the
mass range GeV. The analysis uses collision data at
TeV collected with the ATLAS detector at the LHC, corresponding
to an integrated luminosity of 140 . No significant excess above the
Standard Model (SM) prediction is observed. Assuming the SM Higgs boson
production cross-section, the search sets upper limits at 95% confidence level
on the branching ratio of Higgs bosons decaying into ,
, between 2.2%
and 3.9% depending on the pseudoscalar mass.Peer reviewe
Observation of tt¯ production in the lepton+jets and dilepton channels in p+Pb collisions at √sNN = 8.16 TeV with the ATLAS detector
No full text37 pages in total, author list starting page 20, 3 figures, 1 table,
published in JHEP 11 (2024) 101. All figures including auxiliary figures are
available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2023-32/This paper reports the observation of top-quark pair production in proton-lead
collisions in the ATLAS experiment at the Large Hadron Collider. The measurement is
performed using 165 nb−1 of p+Pb data collected at √
sNN = 8.16 TeV in 2016. Events are
categorised in two analysis channels, consisting of either events with exactly one lepton
(electron or muon) and at least four jets, or events with two opposite-charge leptons and at
least two jets. In both channels at least one b-tagged jet is also required. Top-quark pair
production is observed with a signifcance over fve standard deviations in each channel. The
top-quark pair production cross-section is measured to be σtt¯= 58.1±2.0 (stat.)
+4.8
−4.4
(syst.) nb,
with a total uncertainty of 9%. In addition, the nuclear modifcation factor is measured to
be RpA = 1.090 ± 0.039 (stat.)
+0.094
−0.087 (syst.). The measurements are found to be in good
agreement with theory predictions involving nuclear parton distribution functions.Peer reviewe
Measurement of diferential cross-sections in tt¯ and tt¯+jets production in the lepton+jets fnal state in pp collisions at √s = 13 TeV using 140 fb−1 of ATLAS data
No full text85 pages in total, author list starting page 68, 29 figures, 4
tables, published in JHEP. All figures including auxiliary figures are
available at
http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2020-09/Diferential cross-sections for top-quark pair production, inclusively and in
association with jets, are measured in pp collisions at a centre-of-mass energy of 13 TeV
with the ATLAS detector at the LHC using an integrated luminosity of 140 fb−1
. The
events are selected with one charged lepton (electron or muon) and at least four jets. The
diferential cross-sections are presented at particle level as functions of several jet observables,
including angular correlations, jet transverse momenta and invariant masses of the jets in
the fnal state, which characterise the kinematics and dynamics of the top-antitop system
and the hard QCD radiation in the system with associated jets. The typical precision is
5%–15% for the absolute diferential cross-sections and 2%–4% for the normalised diferential
cross-sections. Next-to-leading-order and next-to-next-to-leading-order QCD predictions are
found to provide an adequate description of the rate and shape of the jet-angular observables.
The description of the transverse momentum and invariant mass observables is improved
when next-to-next-to-leading-order QCD corrections are included.Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen ForschungPeer reviewe
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