K.S. Kumar
A5100727293- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- High-Energy Particle Collisions Research
- Atomic and Subatomic Physics Research
- Nuclear physics research studies
- Particle Detector Development and Performance
- Radiation Detection and Scintillator Technologies
- Quantum, superfluid, helium dynamics
- Particle Accelerators and Free-Electron Lasers
- Advanced NMR Techniques and Applications
- Electron and X-Ray Spectroscopy Techniques
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Photocathodes and Microchannel Plates
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Superconducting Materials and Applications
- Astrophysics and Cosmic Phenomena
- Particle accelerators and beam dynamics
- Computational Physics and Python Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Cosmology and Gravitation Theories
- Nuclear reactor physics and engineering
University of Massachusetts Amherst
2012-2024
KG Hospital
2024
REVA University
2023-2024
UNSW Sydney
2024
Narayana Nethralaya
2024
Apollo Hospitals
2023
Stony Brook University
2015-2022
East Asia School of Theology
2022
State University of New York
2022
King Khalid University
2022
This White Paper presents the science case of an Electron-Ion Collider (EIC), focused on structure and interactions gluon-dominated matter, with intent to articulate it broader nuclear community. It was commissioned by managements Brookhaven National Laboratory (BNL) Thomas Jefferson Accelerator Facility (JLab) objective presenting a summary scientific opportunities goals EIC as follow-up 2007 NSAC Long Range plan. document is culmination community-wide effort in following series workshops...
We report the first measurement of parity-violating asymmetry APV in elastic scattering polarized electrons from Pb208. is sensitive to radius neutron distribution (Rn). The result APV=0.656±0.060(stat)±0.014(syst) ppm corresponds a difference between radii and proton distributions Rn−Rp=0.33−0.18+0.16 fm provides electroweak observation skin which expected heavy, neutron-rich nucleus.Received 12 January 2012DOI:https://doi.org/10.1103/PhysRevLett.108.112502© 2012 American Physical Society
We report a precision measurement of the parity-violating asymmetry $A_{PV}$ in elastic scattering longitudinally polarized electrons from $^{208}$Pb. measure $A_{PV}=550\pm 16 {\rm (stat)}\pm 8\ (syst)}$ parts per billion, leading to an extraction neutral weak form factor $F_W(Q^2 = 0.00616\ GeV}^2) 0.368 \pm 0.013$. Combined with our previous measurement, extracted neutron skin thickness is $R_n-R_p=0.283 0.071$~fm. The result also yields first significant direct interior density...
We report on a search for neutrinoless double-beta decay of $^{136}$Xe with EXO-200. No signal is observed an exposure 32.5 kg-yr, background ~1.5 x 10^{-3} /(kg yr keV) in the $\pm 1\sigma$ region interest. This sets lower limit half-life $T_{1/2}^{0\nu\beta\beta}$($^{136}$Xe) > 1.6 10$^{25}$ (90% CL), corresponding to effective Majorana masses less than 140-380 meV, depending matrix element calculation.
This report is based on a ten-week program Gluons and the quark sea at high-energies, which took place Institute for Nuclear Theory (INT) in Seattle Fall 2010. The principal aim of was to develop sharpen science case an Electron-Ion Collider (EIC), facility that will be able collide electrons positrons with polarized protons light heavy nuclei high energies, offering unprecedented possibilities in-depth studies quantum chromodynamics (QCD). organized around following four major themes: (i)...
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...
We report a precise measurement of the parity-violating (PV) asymmetry A_{PV} in elastic scattering longitudinally polarized electrons from ^{48}Ca. measure A_{PV}=2668±106(stat)±40(syst) parts per billion, leading to an extraction neutral weak form factor F_{W}(q=0.8733 fm^{-1})=0.1304±0.0052(stat)±0.0020(syst) and charge minus F_{ch}-F_{W}=0.0277±0.0055. The resulting neutron skin thickness R_{n}-R_{p}=0.121±0.026(exp)±0.024(model) fm is relatively thin yet consistent with many model...
We report on a precision measurement of the neutron spin structure function ${g}_{1}^{n}$ using deep inelastic scattering polarized electrons by ${}^{3}\mathrm{He}$. For kinematic range $0.014<x<0.7$ and $1<{Q}^{2}<17(\mathrm{GeV}/c{)}^{2}$, we obtain $\ensuremath{\int}{0.014}^{0.7}{g}_{1}^{n}(x)dx\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{-}0.036\ifmmode\pm\else\textpm\fi{}0.004(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.005(\mathrm{syst})$ at an average...
We report on a precision measurement of the parity-violating asymmetry in fixed target electron-electron (Møller) scattering: A(PV) = [-131 +/- 14(stat) 10(syst)] x 10(-9), leading to determination weak mixing angle sin2(thetaW(eff) 0.2397 0.0010(stat) 0.0008(syst), evaluated at Q2 0.026 GeV2. Combining this result with measurements Z0 pole, running is observed over 6sigma significance. The sets constraints new physics effects TeV scale.
We report new measurements of the parity-violating asymmetry ${A}_{\mathrm{PV}}$ in elastic scattering 3 GeV electrons off hydrogen and $^{4}\mathrm{He}$ targets with $⟨{\ensuremath{\theta}}_{\mathrm{lab}}⟩\ensuremath{\approx}6.0\ifmmode^\circ\else\textdegree\fi{}$. The result is ${A}_{\mathrm{PV}}=\mathbf{(}+6.40\ifmmode\pm\else\textpm\fi{}0.23(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.12(\mathrm{syst})\mathbf{)}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$....
We have measured the parity-violating electroweak asymmetry in elastic scattering of polarized electrons from protons. Significant contributions to this could arise strange form factors nucleon. The is $A=\ensuremath{-}15.05\ifmmode\pm\else\textpm\fi{}0.98(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.56(\mathrm{syst})\phantom{\rule{0.3em}{0ex}}\mathrm{ppm}$ at kinematic point $⟨{\ensuremath{\theta}}_{\mathrm{lab}}⟩=12.3\ifmmode^\circ\else\textdegree\fi{}$ and...
This White Paper presents the science case of an Electron-Ion Collider (EIC), focused on structure and interactions gluon-dominated matter, with intent to articulate it broader nuclear community. It was commissioned by managements Brookhaven National Laboratory (BNL) Thomas Jefferson Accelerator Facility (JLab) objective presenting a summary scientific opportunities goals EIC as follow-up 2007 NSAC Long Range plan. document is culmination community-wide effort in following series workshops...
We report the observation of two-neutrino double-beta decay in Xe-136 with T_1/2 = 2.11 +- 0.04 (stat.) 0.21 (sys.) x 10^21 yr. This second order process, predicted by Standard Model, has been observed for several nuclei but not Xe-136. The rate provides new input to matrix element calculations and search more interesting neutrino-less decay, most sensitive probe existence Majorana particles measurement neutrino mass scale.
We use distorted wave electron scattering calculations to extract the weak charge form factor ${F}_{W}(\overline{q})$, radius ${R}_{W}$, and point neutron ${R}_{n}$ of ${}^{208}$Pb from Lead Radius Experiment (PREX) parity-violating asymmetry measurement. The is Fourier transform density at average momentum transfer $\overline{q}=0.475$ fm${}^{\ensuremath{-}1}$. find...
We report on an improved measurement of the $2\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$ half-life ${}^{136}$Xe performed by EXO-200. The use a large and homogeneous time-projection chamber allows for precise estimate fiducial mass used measurement, resulting in small systematic uncertainty. also discuss detail data-analysis methods double-$\ensuremath{\beta}$ decay searches with EXO-200, while emphasizing those directly related to present measurement. is found be...
We review the status of precision measurements weak neutral current interactions, mediated by $Z^0$ boson, at $Q^2\ll M_Z^2$. They can be used to extract values for mixing angle $\sin^2\theta_W$, a fundamental parameter $SU(2)_L\times U(1)_Y$ electroweak sector Standard Model. Apart from providing comprehensive test theory quantum loop level, such allow indirect access new physics effects and beyond TeV scale. After theoretical introduction brief overview three most precise low $Q^2$...
EXO-200 is an experiment designed to search for double beta decay of $^{136}$Xe with a single-phase, liquid xenon detector. It uses active mass 110 kg enriched 80.6% in the isotope 136 ultra-low background time projection chamber capable simultaneous detection ionization and scintillation. This paper describes detector particular attention most innovative aspects design that revolve around reduction backgrounds, efficient use expensive isotopically xenon, optimization energy resolution...
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...
The ratio of the nucleon F_{2} structure functions, F_{2}^{n}/F_{2}^{p}, is determined by MARATHON experiment from measurements deep inelastic scattering electrons ^{3}H and ^{3}He nuclei. was performed in Hall A Facility Jefferson Lab using two high-resolution spectrometers for electron detection, a cryogenic target system which included low-activity tritium cell. data analysis used novel technique exploiting mirror symmetry nuclei, essentially eliminates many theoretical uncertainties...
We have measured the parity-violating electroweak asymmetry in elastic scattering of polarized electrons from 4He at an average angle <theta(lab)> = 5.7 degrees and a four-momentum transfer Q2 0.091 GeV2 . From these data, for first time, strange electric form factor nucleon G(E)s can be isolated. The A(PV) (6.72 +/- 0.84(stat) 0.21(syst) x 10(-6) yields value -0.038 0.042(stat) 0.010(syst), consistent with zero.