638 citations · 1.5k across the 41 of their papers we have counts for
43 papers
Massless fermions in uniform flux background on : Vacuum quantum numbers from single-particle filled modes using lattice regulator
Nikhil Karthik, Rajamani Narayanan, Ray Romero
The quantum numbers of monopoles in in the presence of massless fermions have been analyzed using a uniform flux background in coupled to fermions. An analogous…
Polarized and unpolarized gluon PDFs: generative machine learning applications for lattice QCD matrix elements at short distance and large momentum
Talal Ahmed Chowdhury, Taku Izubuchi, Methun Kamruzzaman +6
Lattice quantum chromodynamics (QCD) calculations share a defining challenge by requiring a small finite range of spatial separation between quark/gluon bilinears for controlla…
Lattice QCD Calculation of -dependent Meson Distribution Amplitudes at Physical Pion Mass with Threshold Logarithm Resummation
Ian Cloet, Xiang Gao, Swagato Mukherjee +5
We present a lattice quantum chromodynamics (QCD) calculation of the -dependent pion and kaon distribution amplitudes (DA) in the framework of large momentum effective theory. T…
Scaling dimension of -flux monopole operator in four-flavor three-dimensional QED using lattice simulation
Nikhil Karthik, Rajamani Narayanan
We numerically address the issue of which monopole operators are relevant under renormalization group flow in three-dimensional parity-invariant noncompact QED with flavors of…
Approaching the conformal WZW behavior in the infrared limit of two-dimensional massless QCD: a lattice study
Nikhil Karthik, Rajamani Narayanan, Sruthi A. Narayanan
Two-dimensional QCD with colors and flavors of massless fermions in the fundamental representation is expected to exhibit conformal behavior in the infrared governed by…
Non-singlet quark helicity PDFs of the nucleon from pseudo-distributions
Robert G. Edwards, Colin Egerer, Joseph Karpie +9
The non-singlet helicity quark parton distribution functions (PDFs) of the nucleon are determined from lattice QCD, by jointly leveraging pseudo-distributions and the distillation…
Unpolarized proton PDF at NNLO from lattice QCD with physical quark masses
Xiang Gao, Andrew D. Hanlon, Jack Holligan +5
We present a lattice QCD calculation of the unpolarized isovector quark parton distribution function (PDF) of the proton utilizing a perturbative matching at next-to-next-to-leadin…
Perturbative computation in a QED-inspired conformal abelian gauge model on the lattice
Nikhil Karthik, Matthew Klein, Rajamani Narayanan
We perform perturbative computations in a lattice gauge theory with a conformal measure that is quadratic in a non-compact abelian gauge field and is nonlocal, as inspired by the i…
Continuum-extrapolated NNLO Valence PDF of Pion at the Physical Point
Xiang Gao, Andrew D. Hanlon, Nikhil Karthik +7
We present lattice QCD calculations of valence parton distribution function (PDF) of pion employing next-to-next-leading-order (NNLO) perturbative QCD matching. Our calculations ar…
Towards the determination of the gluon helicity distribution in the nucleon from lattice quantum chromodynamics
Colin Egerer, Bálint Joó, Joseph Karpie +10
We present the first exploratory lattice quantum chromodynamics (QCD) calculation of the polarized gluon Ioffe-time pseudo-distribution in the nucleon. The Ioffe-time pseudo-distri…
Parton physics of the large- mesons
Nikhil Karthik, Rajamani Narayanan
We initiate the studies on the structural physics of the tower of stable large- mesons through a first computation of the collinear quark-structure of a large- pion using…
Pion distribution amplitude at the physical point using the leading-twist expansion of the quasi-distribution-amplitude matrix element
Xiang Gao, Andrew D. Hanlon, Nikhil Karthik +5
We present a lattice QCD determination of the distribution amplitude (DA) of the pion and the first few Mellin moments from an analysis of the quasi-DA matrix element within the le…
Topological gauge actions on the lattice as Overlap fermion determinants
Nikhil Karthik, Rajamani Narayanan
Overlap fermion on the lattice has been shown to properly reproduce topological aspects of gauge fields. In this paper, we review the derivation of Overlap fermion formalism in a t…
The transversity parton distribution function of the nucleon using the pseudo-distribution approach
Colin Egerer, Christos Kallidonis, Joseph Karpie +8
We present a determination of the non-singlet transversity parton distribution function (PDF) of the nucleon, normalized with respect to the tensor charge at GeV from l…
Bayesian-Wilson coefficients in lattice QCD computations of valence PDFs and GPDs
Nikhil Karthik, Raza Sabbir Sufian
We propose an analysis method for the leading-twist operator product expansion based lattice QCD determinations of the valence parton distribution function (PDF). In the first step…
Towards studying the structural differences between the pion and its radial excitation
Xiang Gao, Nikhil Karthik, Swagato Mukherjee +3
We present an exploratory lattice QCD investigation of the differences between the valence quark structure of pion and its radial excitation in a fixed finite volume usin…
Pion form factor and charge radius from Lattice QCD at physical point
Xiang Gao, Nikhil Karthik, Swagato Mukherjee +3
We present our results on the electromagnetic form factor of pion over a wide range of using lattice QCD simulations with Wilson-clover valence quarks and HISQ sea quarks. We…
Quark distribution inside a pion in many-flavor (2 + 1)-dimensional QCD using lattice computations: UV listens to IR
Nikhil Karthik
We study the changes in the short-distance quark structure of the Nambu-Goldstone boson when the long-distance symmetry-breaking scales are depleted controllably. We achieve this b…
QED-inspired three-dimensional conformal lattice gauge theory without fine-tuning
Nikhil Karthik, Rajamani Narayanan
We construct a conformal lattice theory with only gauge degrees of freedom based on the induced non-local gauge action in QED coupled to large number of flavors of massless…
Valence parton distribution of pion from lattice QCD: Approaching continuum
Xiang Gao, Luchang Jin, Christos Kallidonis +6
We present a high-statistics lattice QCD determination of the valence parton distribution function (PDF) of the pion, with a mass of 300 MeV, using two very fine lattice spacings o…
Isovector parton distribution functions of the proton on a superfine lattice
Zhouyou Fan, Xiang Gao, Ruizi Li +7
We study isovector unpolarized and helicity parton distribution functions (PDF) of the proton within the framework of Large Momentum Effective Theory. We use a gauge ensemble, gene…
Pion valence quark PDF from lattice QCD
Charles Shugert, Xiang Gao, Taku Izubichi +7
We present lattice results on the valence-quark structure of the pion using a coordinate space method within the framework of Large Momentum Effective Theory (LaMET). In this metho…
Numerical determination of monopole scaling dimension in parity-invariant three-dimensional non-compact QED
Nikhil Karthik, Rajamani Narayanan
We present a direct Monte-Carlo determination of the scaling dimension of a topological defect operator in the infrared fixed point of a three-dimensional interacting quantum field…
A curious behavior of three-dimensional lattice Dirac operators coupled to monopole background
Nikhil Karthik, Rajamani Narayanan
We investigate numerically the effect of regulating fermions in the presence of singular background fields in three dimensions. For this, we couple free lattice fermions to a backg…