S. Feyzbakhsh
A5091265032- Algebraic Geometry and Number Theory
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Advanced Algebra and Geometry
- Particle physics theoretical and experimental studies
- Radiation Detection and Scintillator Technologies
- Geometry and complex manifolds
- Atomic and Subatomic Physics Research
- Algebraic structures and combinatorial models
- Particle Detector Development and Performance
- Homotopy and Cohomology in Algebraic Topology
- Astrophysics and Cosmic Phenomena
- Manufacturing Process and Optimization
- Nuclear physics research studies
- Scheduling and Optimization Algorithms
- Nonlinear Waves and Solitons
- Vietnamese History and Culture Studies
- Advanced Manufacturing and Logistics Optimization
- Assembly Line Balancing Optimization
- Geometric and Algebraic Topology
- Atmospheric Ozone and Climate
- Quantum, superfluid, helium dynamics
- Black Holes and Theoretical Physics
- Evolutionary Algorithms and Applications
- Advanced Numerical Analysis Techniques
Imperial College London
2017-2024
Sharif University of Technology
2008-2024
University of Massachusetts Amherst
2016-2023
Université de Montpellier
2023
Centre National de la Recherche Scientifique
2023
Sorbonne Université
2023
Laboratoire de Physique Théorique et Hautes Energies
2023
Laboratoire Charles Coulomb
2023
McGill University
2021
Lawrence Livermore National Laboratory
2020
A search for neutrinoless double-beta decay ($0\nu\beta\beta$) in $^{136}$Xe is performed with the full EXO-200 dataset using a deep neural network to discriminate between $0\nu\beta\beta$ and background events. Relative previous analyses, signal detection efficiency has been raised from 80.8% 96.4$\pm$3.0% energy resolution of detector at Q-value improved $\sigma/E=1.23\%$ $1.15\pm0.02\%$ upgraded detector. Accounting new data, median 90% confidence level half-life sensitivity this analysis...
Results from a search for neutrinoless double-beta decay (0νββ) of ^{136}Xe are presented using the first year data taken with upgraded EXO-200 detector. Relative to previous searches by EXO-200, energy resolution detector has been improved σ/E=1.23%, electric field in drift region raised 50%, and system suppress radon volume between cryostat lead shielding implemented. In addition, analysis techniques that improve topological discrimination 0νββ background events have developed....
The next-generation Enriched Xenon Observatory (nEXO) is a proposed experiment to search for neutrinoless double beta ($0\nu\beta\beta$) decay in $^{136}$Xe with target half-life sensitivity of approximately $10^{28}$ years using $5\times10^3$ kg isotopically enriched liquid-xenon time projection chamber. This improvement two orders magnitude over current limits obtained by significant increase the mass, monolithic and homogeneous configuration active medium, multi-parameter measurements...
Abstract The nEXO neutrinoless double beta (0 νββ ) decay experiment is designed to use a time projection chamber and 5000 kg of isotopically enriched liquid xenon search for the in 136 Xe. Progress detector design, paired with higher fidelity its simulation an advanced data analysis, based on one used final results EXO-200, produce sensitivity prediction that exceeds half-life 10 28 years. Specifically, improvements have been made understanding production scintillation photons charge as...
The projected performance and detector configuration of nEXO are described in this pre-Conceptual Design Report (pCDR). is a tonne-scale neutrinoless double beta ($0νββ$) decay search $^{136}$Xe, based on the ultra-low background liquid xenon technology validated by EXO-200. With $\simeq$ 5000 kg enriched to 90% isotope 136, has half-life sensitivity approximately $10^{28}$ years. This represents an improvement about two orders magnitude with respect current results. Based experience gained...
We show that the moduli space M X .v/ of Gieseker stable sheaves on a smooth cubic threefold with Chern character v D 3; H; 1 2 H ; 6 3 is and dimension four.Moreover, Abel-Jacobi map to intermediate Jacobian maps it birationally onto theta divisor ‚, contracting only copy singular point 0 ‚.We use this result give new proof categorical version Torelli theorem for threefolds, which says can be recovered from its Kuznetsov component Ku.X / b .X /.Similarly, leads description singularity...
We apply deep neural networks (DNN) to data from the EXO-200 experiment. In studied cases, DNN is able reconstruct relevant parameters—total energy and position—directly raw digitized waveforms, with minimal exceptions. For first time, developed algorithms are evaluated on real detector calibration data. The accuracy of reconstruction either reaches or exceeds what was achieved by conventional approaches over course Most existing event classification in particle physics trained Monte Carlo...
In this paper, we conduct the first systematic investigation of twisted cubics on Gushel-Mukai (GM) fourfolds. We then study double EPW cube, a 6-dimensional hyperk\"ahler manifold associated with general GM fourfold $X$, through Bridgeland moduli space, and show that it is maximal rationally connected (MRC) quotient Hilbert scheme $X$. also prove cube admits covering by Lagrangian subvarieties constructed from schemes threefolds, which provides new example for conjecture O'Grady.
The EXO-200 Collaboration is searching for neutrinoless double $\ensuremath{\beta}$ decay using a liquid xenon (LXe) time projection chamber. This measurement relies on modeling the transport of charge deposits produced by interactions in LXe to allow discrimination between signal and background events. Here we present measurements transverse diffusion constant drift velocity electrons at fields 20 V/cm 615 data. At operating field 380 measures...
Future tonne-scale liquefied noble gas detectors depend on efficient light detection in the VUV range. In past years Silicon Photomultipliers (SiPMs) have emerged as a valid alternative to standard photomultiplier tubes or large area avalanche photodiodes. The next generation double beta decay experiment, nEXO, with 5 tonne liquid xenon time projection chamber, will use SiPMs for detecting $178\,\text{nm}$ scintillation light, order achieve an energy resolution of $\sigma / Q_{\beta\beta} =...
Liquid xenon (LXe) is employed in a number of current and future detectors for rare event searches. We use the EXO-200 experimental data to measure absolute scintillation ionization yields generated by $\ensuremath{\gamma}$ interactions from $^{228}\mathrm{Th}$ (2615 keV), $^{226}\mathrm{Ra}$ (1764 $^{60}\mathrm{Co}$ (1332 keV 1173 keV) calibration sources, over range electric fields. The $W$ value that defines recombination-independent energy scale measured be...
As neutrinoless double-beta decay experiments become more sensitive and intrinsic radioactivity in detector materials is reduced, previously minor contributions to the background must be understood eliminated. With this mind, cosmogenic backgrounds have been studied with EXO-200 experiment. Using TPC, muon flux (through a flat horizontal surface) underground at Waste Isolation Pilot Plant (WIPP) has measured {\Phi} = 4.07 $\pm$ 0.14 (sys) 0.03 (stat) $\times$ $10^{-7}$cm$^{-2}$ s$^{-1}$,...
We work on a projective threefold $X$ which satisfies the Bogomolov-Gieseker conjecture of Bayer-Macr\`i-Toda, such as $\mathbb P^3$ or quintic threefold. prove certain moduli spaces 2-dimensional torsion sheaves are smooth bundles over Hilbert schemes ideal curves and points in $X$. When is Calabi-Yau this gives simple wall crossing formula expressing curve counts (and so ultimately Gromov-Witten invariants) terms D4-D2-D0 branes. These latter invariants predicted to have modular properties...
Abstract We prove an effective restriction theorem for stable vector bundles E on a smooth projective variety: $$E|_D$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mi>E</mml:mi><mml:mo>|</mml:mo></mml:mrow><mml:mi>D</mml:mi></mml:msub></mml:math> is (semi)stable all irreducible divisors $$D \in |kH|$$...
We present a search for electron-recoil signatures from the charged-current absorption of fermionic dark matter using EXO-200 detector. report an average background rate $6.8\ifmmode\times\else\texttimes\fi{}{10}^{4}\text{ }\text{ }\mathrm{cts}\text{ }{\mathrm{kg}}^{\ensuremath{-}1}\text{ }{\mathrm{yr}}^{\ensuremath{-}1}\text{ }{\mathrm{keV}}^{\ensuremath{-}1}$ above 4 MeV and find no statistically significant excess over our projection. Using total $^{136}\mathrm{Xe}$ exposure 234.1 kg yr,...
A search for Majoron-emitting modes of the neutrinoless double-beta decay $^{136}$Xe is performed with full EXO-200 dataset. This dataset consists a total exposure 234.1 kg$\cdot$yr, and includes data detector upgrades that have improved energy threshold relative to previous searches. lower limit T$_{1/2}^{\rm{^{136}Xe}}>$4.3$\cdot$10$^{24}$ yr at 90\% C.L. on half-life spectral index $n=1$ Majoron was obtained, factor 3.6 more stringent than from EXO-200, corresponding constraint...
Understanding reflective properties of materials and photodetection efficiency (PDE) photodetectors is important for optimizing energy resolution sensitivity the next generation neutrinoless double beta decay, direct detection dark matter, neutrino oscillation experiments that will use noble liquid gases, such as nEXO, DARWIN, DarkSide-20k, DUNE . Little information currently available about reflectivity PDE in because measurements are difficult to conduct a cryogenic environment at short...
Searches for double beta decay of $^{134}$Xe were performed with EXO-200, a single-phase liquid xenon detector designed to search neutrinoless $^{136}$Xe. Using an exposure $29.6\text{ kg}\!\cdot\!\text{yr}$, the lower limits $\text{T}_{1/2}^{2\nu\beta\!\beta}>8.7\cdot10^{20}\text{ yr}$ and $\text{T}_{1/2}^{0\nu\beta\!\beta}>1.1\cdot10^{23}\text{ at 90% confidence level derived, corresponding half-life sensitivities $1.2\cdot10^{21}\text{ $1.9\cdot10^{23}\text{ yr}$. These exceed those in...
Abstract Let C be a curve of genus <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"><m:mrow><m:mi>g</m:mi><m:mo>=</m:mo><m:mn>11</m:mn></m:mrow></m:math> {g=11} or xmlns:m="http://www.w3.org/1998/Math/MathML"><m:mrow><m:mi>g</m:mi><m:mo>≥</m:mo><m:mn>13</m:mn></m:mrow></m:math> {g\geq 13} on K3 surface whose Picard group is generated by the class xmlns:m="http://www.w3.org/1998/Math/MathML"><m:mrow><m:mo stretchy="false">[</m:mo><m:mi>C</m:mi><m:mo...
A search for instability of nucleons bound in $^{136}$Xe nuclei is reported with 223 kg$\cdot$yr exposure the EXO-200 experiment. Lifetime limits 3.3$\times 10^{23}$ and 1.9$\times yrs are established nucleon decay to $^{133}$Sb $^{133}$Te, respectively. These most stringent date, exceeding prior by a factor 9 7,
EXO-200 is a single phase liquid xenon detector designed to search for neutrinoless double-beta decay of $^{136}$Xe the ground state $^{136}$Ba. We report here on two-neutrino first $0^+$ excited state, $0^+_1$, $^{136}$Ba based 100 kg$\cdot$yr exposure $^{136}$Xe. Using specialized analysis employing machine learning algorithm, we obtain 90% CL half-life sensitivity $1.7 \times 10^{24}$ yr. find no statistically significant evidence $2\nu\beta\beta$ resulting in lower limit $T^{2\nu}_{1/2}$...