Nilmani Mathur

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The glueball-to-vacuum matrix elements of local gluonic operators in scalar, tensor, and pseudoscalar channels are investigated numerically on several anisotropic lattices with the spatial lattice spacing ranging from 0.1– 0.2 fm. These matrix elements are needed to predict the glueball branching ratios in J= radiative decays which will help identify the(More)
We calculate the lattice two-point function of topological charge density in pure-glue QCD using the discretization of the operator based on the overlap Dirac matrix. Utilizing data at three lattice spacings it is shown that the continuum limit of the correlator complies with the requirement of non-positivity at non-zero distances. For our choice of the(More)
We study the a0 and σ mesons with the overlap fermion in the chiral regime with the pion mass as low as 182MeV in the quenched approximation. After the ηN ghost states are separated, we find that the a0 mass with qq̄ interpolation field to be almost independent of the quark mass in the region below the strange quark mass. The chirally extrapolated results(More)
Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA Department of Physics, University of Maryland, College Park, Maryland 20742, USA Department of Physics, University of the Pacific, Stockton, California 95211, USA Department of Theoretical(More)
Stochastic noise estimator method is a powerful tool to calculate the disconnected insertion involving quark loops. We study the variance reduction technique with unbiased subtraction. We use the complex Z2 noise to calculate the quark loops on a 16 × 24 lattice with β = 6.0 and κ = 0.154. Unbiased subtraction method is performed by using hoping parameter(More)
I. HORVÁTH, S.J. DONG, T. DRAPER, K.F. LIU, N. MATHUR, F.X. LEE, H.B. THACKER AND J.B. ZHANG Department of Physics, University of Kentucky, Lexington, KY 40506 Center for Nuclear Studies and Department of Physics, George Washington University, Washington, DC 20052 Jefferson Lab, 12000 Jefferson Avenue, Newport News, VA 23606 Department of Physics,(More)
Using the constrained curve fitting method and overlap fermions with the lowest pion mass at 180MeV, we observe that the masses of the first positive and negative parity excited states of the nucleon tend to cross over as the quark masses are taken to the chiral limit. Both results at the physical pion mass agree with the experimental values of the Roper(More)
We calculate the strange magnetic moment of the nucleon on a quenched 16 × 24 lattice at β = 6.0, and with Wilson fermions at κ = 0.148, 0.152, and 0.154. The strange quark contribution from the disconnected insertion is estimated stochastically by employing the Z2 noise method. Using an unbiased subtraction along with the help of charge conjugation and(More)
We study the strangeness contribution to nucleon matrix elements using N f = 2 + 1 dynamical clover fermion configurations generated by the CP-PACS/JLQCD collaboration. In order to evaluate the disconnected insertion (DI), we use the Z(4) stochastic method, along with unbiased subtraction from the hopping parameter expansion which reduces the off-diagonal(More)
We present progress made by the Hadron Spectrum Collaboration (HSC) in determining the tower of excited nucleon states using 2+1-flavor anisotropic clover lattices. The HSC has been investigating interpolating operators projected into irreducible representations of the cubic group in order to better calculate two-point correlators for nucleon spectroscopy;(More)