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K. Kumar

Publications and source records attributed to K. Kumar.

At least 37 records · Page 2Linked to original sources
arXiv2014

Electron Ion Collider: The Next QCD Frontier - Understanding the glue that binds us all

This White Paper presents the science case of an Electron-Ion Collider (EIC), focused on the structure and interactions of gluon-dominated matter, with the intent to articulate it to the broader nuclear science community. It was commissioned by the managements of Brookhaven National Laboratory (BNL) and Thomas Jefferson National Accelerator Facility (JLab) with the objective of presenting a summary of scientific opportunities and goals of the EIC as a follow-up to the 2007 NSAC Long Range plan. This document is a culmination of a community-wide effort in nuclear science following a series of workshops on EIC physics and, in particular, the focused ten-week program on "Gluons and quark sea at high energies" at the Institute for Nuclear Theory in Fall 2010. It contains a brief description of a few golden physics measurements along with accelerator and detector concepts required to achieve them, and it benefited from inputs from the users' communities of BNL and JLab. This White Paper offers the promise to propel the QCD science program in the U.S., established with the CEBAF accelerator at JLab and the RHIC collider at BNL, to the next QCD frontier.

nucl-ex↗
arXiv2014

Homoclinic bifurcations in low-Prandtl-number Rayleigh-Bénard convection with uniform rotation

We present results of direct numerical simulations on homoclinic gluing and ungluing bifurcations in low-Prandtl-number ($ 0 \leq Pr \leq 0.025 $) Rayleigh-Bénard system rotating slowly and uniformly about a vertical axis. We have performed simulations with \textit{stress-free} top and bottom boundaries for several values of Taylor number ($5 \leq Ta \leq 50$) near the instability onset. We observe a single homoclinic ungluing bifurcation, marked by the spontaneous breaking of a larger limit cycle into two limit cycles with the variation of the reduced Rayleigh number $r$ for smaller values of $Ta (< 25)$. A pair of homoclinic bifurcations, instead of one bifurcation, is observed with variation of $r$ for slightly higher values of $Ta$ ($25 \leq Ta \leq 50$) in the same fluid dynamical system. The variation of the bifurcation threshold with $Ta$ is also investigated. We have also constructed a low-dimensional model which qualitatively captures the dynamics of the system near the homoclinic bifurcations for low rotation rates. The model is used to study the unfolding of bifurcations and the variation of the homoclinic bifurcation threshold with $Pr$.

physics.flu-dyn↗
arXiv2014

Planning the Future of U.S. Particle Physics (Snowmass 2013): Chapter 2: Intensity Frontier

These reports present the results of the 2013 Community Summer Study of the APS Division of Particles and Fields ("Snowmass 2013") on the future program of particle physics in the U.S. Chapter 2, on the Intensity Frontier, discusses the program of research with high-intensity beams and rare processes. This area includes experiments on neutrinos, proton decay, charged-lepton and quark weak interactions, atomic and nuclear probes of fundamental symmetries, and searches for new, light, weakly-interacting particles.

hep-ex↗
arXiv2014

Higgs Working Group Report of the Snowmass 2013 Community Planning Study

This report summarizes the work of the Energy Frontier Higgs Boson working group of the 2013 Community Summer Study (Snowmass). We identify the key elements of a precision Higgs physics program and document the physics potential of future experimental facilities as elucidated during the Snowmass study. We study Higgs couplings to gauge boson and fermion pairs, double Higgs production for the Higgs self-coupling, its quantum numbers and $CP$-mixing in Higgs couplings, the Higgs mass and total width, and prospects for direct searches for additional Higgs bosons in extensions of the Standard Model. Our report includes projections of measurement capabilities from detailed studies of the Compact Linear Collider (CLIC), a Gamma-Gamma Collider, the International Linear Collider (ILC), the Large Hadron Collider High-Luminosity Upgrade (HL-LHC), Very Large Hadron Colliders up to 100 TeV (VLHC), a Muon Collider, and a Triple-Large Electron Positron Collider (TLEP).

hep-ex↗
arXiv2013

Charged Leptons

This is the report of the Intensity Frontier Charged Lepton Working Group of the 2013 Community Summer Study "Snowmass on the Mississippi", summarizing the current status and future experimental opportunities in muon and tau lepton studies and their sensitivity to new physics. These include searches for charged lepton flavor violation, measurements of magnetic and electric dipole moments, and precision measurements of the decay spectrum and parity-violating asymmetries.

hep-ex↗
arXiv2011

Gluons and the quark sea at high energies: distributions, polarization, tomography

This report is based on a ten-week program on "Gluons and the quark sea at high-energies", which took place at the Institute for Nuclear Theory in Seattle in Fall 2010. The principal aim of the program was to develop and sharpen the science case for an Electron-Ion Collider (EIC), a facility that will be able to collide electrons and positrons with polarized protons and with light to heavy nuclei at high energies, offering unprecedented possibilities for in-depth studies of quantum chromodynamics. This report is organized around four major themes: i) the spin and flavor structure of the proton, ii) three-dimensional structure of nucleons and nuclei in momentum and configuration space, iii) QCD matter in nuclei, and iv) Electroweak physics and the search for physics beyond the Standard Model. Beginning with an executive summary, the report contains tables of key measurements, chapter overviews for each of the major scientific themes, and detailed individual contributions on various aspects of the scientific opportunities presented by an EIC.

nucl-th↗
arXiv2011

Xenon purity analysis for EXO-200 via mass spectrometry

We describe purity measurements of the natural and enriched xenon stockpiles used by the EXO-200 double beta decay experiment based on a mass spectrometry technique. The sensitivity of the spectrometer is enhanced by several orders of magnitude by the presence of a liquid nitrogen cold trap, and many impurity species of interest can be detected at the level of one part-per-billion or better. We have used the technique to screen the EXO-200 xenon before, during, and after its use in our detector, and these measurements have proven useful. This is the first application of the cold trap mass spectrometry technique to an operating physics experiment.

physics.ins-det↗
arXiv2011

Autonomous Traffic Control System Using Agent Based Technology

The way of analyzing, designing and building of real-time projects has been changed due to the rapid growth of internet, mobile technologies and intelligent applications. Most of these applications are intelligent, tiny and distributed components called as agent. Agent works like it takes the input from numerous real-time sources and gives back the real-time response. In this paper how these agents can be implemented in vehicle traffic management especially in large cities and identifying various challenges when there is a rapid growth of population and vehicles. In this paper our proposal gives a solution for using autonomous or agent based technology. These autonomous or intelligent agents have the capability to observe, act and learn from their past experience. This system uses the knowledge flow of precedent signal or data to identify the incoming flow of forthcoming signal. Our architecture involves the video analysis and exploration using some Intelligence learning algorithm to estimate and identify the flow of traffic.

cs.MA↗
arXiv2011

A xenon gas purity monitor for EXO

We discuss the design, operation, and calibration of two versions of a xenon gas purity monitor (GPM) developed for the EXO double beta decay program. The devices are sensitive to concentrations of oxygen well below 1 ppb at an ambient gas pressure of one atmosphere or more. The theory of operation of the GPM is discussed along with the interactions of oxygen and other impurities with the GPM's tungsten filament. Lab tests and experiences in commissioning the EXO-200 double beta decay experiment are described. These devices can also be used on other noble gases.

physics.ins-det↗
arXiv2011

A magnetically-driven piston pump for ultra-clean applications

A magnetically driven piston pump for xenon gas recirculation is presented. The pump is designed to satisfy extreme purity and containment requirements, as is appropriate for the recirculation of isotopically enriched xenon through the purification system and large liquid xenon TPC of EXO-200. The pump, using sprung polymer gaskets, is capable of pumping more than 16 standard liters per minute (SLPM) of xenon gas with 750 torr differential pressure.

physics.ins-det↗
arXiv2011

Results from a Prototype Chicane-Based Energy Spectrometer for a Linear Collider

The International Linear Collider and other proposed high energy e+ e- machines aim to measure with unprecedented precision Standard Model quantities and new, not yet discovered phenomena. One of the main requirements for achieving this goal is a measurement of the incident beam energy with an uncertainty close to 1e-4. This article presents the analysis of data from a prototype energy spectrometer commissioned in 2006--2007 in SLAC's End Station A beamline. The prototype was a 4-magnet chicane equipped with beam position monitors measuring small changes of the beam orbit through the chicane at different beam energies. A single bunch energy resolution close to 5e-4 was measured, which is satisfactory for most scenarios. We also report on the operational experience with the chicane-based spectrometer and suggest ways of improving its performance.

physics.acc-ph↗
arXiv2010

A Novel Approach Towards Cost Effective Region-Based Group Key Agreement Protocol for Peer - to - Peer Information Sharing in Mobile Ad Hoc Networks

Peer-to-peer systems have gained a lot of attention as information sharing systems for the widespread exchange of resources and voluminous information that is easily accessible among thousands of users. However, current peer-to-peer information sharing systems work mostly on wired networks. With the growing number of communication-equipped mobile devices that can self-organize into infrastructure-less communication platform, namely mobile ad hoc networks (MANETs), peer-to-peer information sharing over MANETs becomes a promising research area. In this paper, we propose a Region-Based structure that enables efficient and secure peer-to-peer information sharing over MANETs. The implementation shows that the proposed scheme is Secure, scalable, efficient, and adaptive to node mobility and provides Reliable information sharing.

cs.CR↗
arXiv2010

A simple radionuclide-driven single-ion source

We describe a source capable of producing single barium ions through nuclear recoils in radioactive decay. The source is fabricated by electroplating 148Gd onto a silicon α-particle detector and vapor depositing a layer of BaF2 over it. 144Sm recoils from the alpha decay of 148Gd are used to dislodge Ba+ ions from the BaF2 layer and emit them in the surrounding environment. The simultaneous detection of an α particle in the substrate detector allows for tagging of the nuclear decay and of the Ba+ emission. The source is simple, durable, and can be manipulated and used in different environments. We discuss the fabrication process, which can be easily adapted to emit most other chemical species, and the performance of the source.

physics.atom-ph↗
arXiv2010

Design And Implementation Of Multilevel Access Control In Medical Image Transmission Using Symmetric Polynomial Based Audio Steganography

...The steganography scheme makes it possible to hide the medical image in different bit locations of host media without inviting suspicion. The Secret file is embedded in a cover media with a key. At the receiving end the key can be derived by all the classes which are higher in the hierarchy using symmetric polynomial and the medical image file can be retrieved. The system is implemented and found to be secure, fast and scalable. Simulation results show that the system is dynamic in nature and allows any type of hierarchy. The proposed approach performs better even during frequent member joins and leaves. The computation cost is reduced as the same algorithm is used for key computation and descendant key derivation. Steganographic technique used in this paper does not use the conventional LSB's and uses two bit positions and the hidden data occurs only from a frame which is dictated by the key that is used. Hence the quality of stego data is improved.

cs.MM↗
arXiv2009

Characterization of large area APDs for the EXO-200 detector

EXO-200 uses 468 large area avalanche photodiodes (LAAPDs) for detection of scintillation light in an ultra-low-background liquid xenon (LXe) detector. We describe initial measurements of dark noise, gain and response to xenon scintillation light of LAAPDs at temperatures from room temperature to 169K - the temperature of liquid xenon. We also describe the individual characterization of more than 800 LAAPDs for selective installation in the EXO-200 detector.

physics.ins-det↗
arXiv2008

3He Spin-Dependent Cross Sections and Sum Rules

We present a measurement of the spin-dependent cross sections for the \vec{^3He}(\vec{e},e')X} reaction in the quasielastic and resonance regions at four-momentum transfer 0.1 < Q^2< 0.9 GeV^2. The spin-structure functions have been extracted and used to evaluate the nuclear Burkhardt--Cottingham and extended GDH sum rules for the first time. Impulse approximation and exact three-body Faddeev calculations are also compared to the data in the quasielastic region.

nucl-ex↗
arXiv2001

Hard Photon production from unsaturated quark gluon plasma at two loop level

The hard photon productions from bremsstrahlung and annihilation with scattering that arise at two loop level are estimated from a chemically non-equilibrated quark gluon plasma using the frame work of thermal field theory. Although, the rate of photon production is suppressed due to unsaturated phase space, the above suppression is relatively smaller than expected due to an additional collinear enhancement (arise due to decrease in thermal quark mass) as compared to it's equilibrium counterpart. Interestingly, unlike the one loop case, the reduction in the two loop processes are found to be independent of gluon chemical poential, but strongly depends on quark fugacity. It is also found that, since the phase space suppression is highest for annihilation with scattering, the photon production is entirely dominated by bremsstrahlung mechanism at all energies. This is to be contrasted with the case of the equilibrated plasma where annihilation with scattering dominates the photon production particularly at higher energies.

hep-ph↗