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Asmita Mukherjee

Publications and source records attributed to Asmita Mukherjee.

At least 19 recordsLinked to original sources
arXiv2026

Gravitational transverse momentum dependent distributions for the gluons

We investigate the momentum-space structure of the gauge-invariant gluon energy-momentum tensor (EMT) for spin-$0$ and spin-$\tfrac{1}{2}$ hadrons in the light-front formalism. We parameterize the nonlocal gluon EMT in terms of so-called gluon gravitational transverse-momentum-dependent distributions (gravitational TMDs) and derive their connections to twist-2 and twist-3 gluon TMDs. Moreover, we demonstrate that particular components of the gluon EMT encode information about the average kinetic four-momentum of gluons and the internal mechanical properties of hadrons-such as pressure and shear distributions.

hep-ph↗
arXiv2026

Relativistic spatial distributions of transverse angular momentum

In our previous work [C. Lorc\'e et al., Phys. Lett. B 868 (2025) 139792], we investigated the 2D spatial distributions of transverse total angular momentum, including orbital angular momentum and intrinsic spin, relative to the canonical center (or center of spin). In the present work, we extend this analysis in two directions. First, we study the corresponding transverse boost distributions relative to the canonical center. Second, since the definition of generalized angular momentum density depends crucially on the choice of pivot, we analyze how the spatial distributions of transverse total angular momentum and boost are modified when they are defined relative to different relativistic centers, viz.~the relativistic centers of mass, energy, and spin. Considering spin-1/2 targets, we derive the corresponding 2D spatial distributions in the transverse plane, and further investigate how the spatial patterns evolve under longitudinal Lorentz boosts. Additionally, we provide the corresponding light-front distributions in the transverse plane, establishing a clear connection between the instant-form and light-front descriptions of transverse angular momentum and boost.

hep-ph↗
arXiv2026

The effect of TMD evolution on the Sivers asymmetry in back-to-back $J/\psi+\gamma$ and $J/\psi+\text{jet}$ production at the Electron-Ion-Collider

We present an estimate of the Sivers asymmetry in back-to-back $J/\psi$-photon and $J/\psi$-jet production in electron-proton collisions in the kinematics of the upcoming Electron-Ion Collider (EIC) in a transverse momentum dependent (TMD) factorization framework, and also incorporating the TMD evolution. We use the non-relativistic Quantum Chromodynamics (NRQCD) model to study the production mechanism of $J/\psi$. The gluon induced channel dominates, and these are promising probes of the less known gluon Sivers function. We incorporate the TMD evolution in the cross section and Sivers asymmetry in the Collins-Soper-Sterman (CSS) approach and show that the asymmetry is sizable even after the evolution. Although the cross section for $J/\psi$-jet production depends on the long-distance matrix element (LDME) set chosen, the asymmetry remains largely unaffected. The asymmetry is independent of the LDME at leading order for $J/\psi$-photon production. Thus, the Sivers asymmetry in both processes is a robust probe of the gluon Sivers function.

hep-ph↗
arXiv2026

Gravitational transverse momentum distribution of proton

We present the first study of quark gravitational transverse-momentum distributions within the light-front quark--diquark model (LFQDM) inspired by the soft-wall AdS/QCD framework. We derive analytical expressions for the six unpolarized (T-even) gravitational transverse-momentum-dependent distributions (gravitational--TMDs) for up and down quarks within the model and compute the corresponding gravitational parton distribution functions (gravitational--PDFs). We further verify that these unpolarized gravitational--TMDs satisfy the model-independent relations with quark TMDs. In addition, we explore the connection of gravitational TMDs with the transverse isotropic pressure and shear-force distributions in momentum space, as well as with the average longitudinal momentum carried by up and down quarks within the model.

hep-ph↗
arXiv2026

Spin-Orbit Correlations in the Pion and the Role of Quark-gluon Interaction

We study the spin-orbit correlations (SOCs) of the pion using overlap of light-front wave functions (LFWFs). Going beyond the leading Fock sector, we incorporate one gluon in the wave function. The analytic form of the higher Fock component of the LFWF is constructed by incorporating a perturbative gluon to the pion state. This allows us to explore the role of quark-gluon interactions in the spin-orbit correlation within a model calculation. We investigate the kinetic and canonical spin-orbit correlations of quarks in the pion, which arise from different decompositions of the energy-momentum tensor. We further explore the difference between kinetic and canonical SOC arising from the inclusion of higher Fock sector containing gluon.

hep-ph↗
arXiv2025

Gluon generalized transverse momentum dependent parton distributions and Wigner functions of the Proton

We present a calculation of the leading-twist (twist-2) generalized transverse momentum distributions (GTMDs) for unpolarized and longitudinally polarized gluons in the proton, using a recently developed light-front gluon spectator model inspired by the soft-wall AdS/QCD prediction. We calculate the gluon GTMDs for non-zero skewness, using overlaps in terms of light-front wave functions. We also compute the gluon Wigner distributions for various polarization configurations of the proton target, including unpolarized, longitudinally polarized, and transversely polarized states. We present these Wigner distributions and the associated spin densities in both the transverse momentum plane and the transverse impact parameter plane. Furthermore, we evaluate the gluon orbital angular momentum and spin-orbit correlations, and extract the generalized parton distribution and transverse momentum-dependent distribution limits of the GTMDs.

hep-ph↗
arXiv2025

Mapping the transverse spin sum rule in position space

We discuss in detail the relativistic spatial distribution of transverse angular momentum, including both orbital and intrinsic spin contributions. Using the quantum phase-space formalism, we begin with the definition of the three-dimensional spatial distributions of transverse orbital angular momentum and intrinsic spin in a generic Lorentz frame. By integrating these three-dimensional spatial distributions over the longitudinal axis, we derive for the first time the relativistic spatial distributions of transverse orbital angular momentum, intrinsic spin, and total angular momentum for spin-0 and spin-1/2 targets in the transverse plane. We verify the transverse spin sum rule about the relativistic center of spin for spin-0 and spin-1/2 systems, and find that the transverse total angular momentum distribution is non-trivial, even for spin-0 targets. We also show how the distributions of transverse orbital angular momentum, intrinsic spin, and total angular momentum change with the target momentum.

hep-ph↗
arXiv2025

Gluon gravitational form factors of the proton in a light-front spectator model

We calculate the gluon gravitational form factors (GFFs) of the proton using a light-front spectator model based on soft-wall AdS/QCD, where the active parton is a gluon. The model parameters are determined by fitting the unpolarized gluon distribution function to the NNPDF3.0nlo dataset. Subsequently, we predict the polarized gluon distribution, finding consistency with global analyses. Our predictions for the gluon GFFs show good agreement with recent lattice QCD simulations and experimental extractions. Using these gluon GFFs, we compute the contribution of the gluon to the proton mass and mechanical radii. We also analyze the gluonic contribution to the two-dimensional Galilean densities, including energy density, radial and tangential pressure, isotropic pressure, and pressure anisotropy of the proton.

hep-ph↗
arXiv2024

Gluon contribution to the angular momentum distribution of a dressed quark state

We compute the contribution of the gluonic component of the energy-momentum tensor (EMT) to the angular momentum density in various decompositions. We use the light-front Hamiltonian technique, and a two-component formalism in light-front gauge, where the constrained degrees of freedom are eliminated. Instead of a nucleon, we consider a simple composite spin-$1/2$ state, namely a quark dressed with a gluon. We present two dimensional light-front distributions in transverse impact parameter space, and compare the different angular momentum decompositions at the density level. Incorporating also the contribution coming from the quark part of the EMT, we verify the spin sum rule for such a state.

hep-ph↗
arXiv2024

Proton gluonic distributions in a light front spectator model

We investigate the leading-twist gluonic distribution functions within the proton by formulating a light-front spectator model. The proton light-front wave functions (LFWFs) are adopted from the soft-wall AdS/QCD predictions, and the model parameters are determined using the gluon unpolarized parton distribution function from the NNPDF3.0nlo dataset. Furthermore, we demonstrated the model calculations for gluon transverse momentum distributions (TMDs) and generalized parton distributions (GPDs). We also predicted the gluon spin and orbital angular momentum (OAM) contributions to the total proton spin.

hep-ph↗
arXiv2024

TMD evolution effect on $\cos2\phi$ azimuthal asymmetry in a back-to-back production of $J/\psi$ and jet at the EIC

A back-to-back semi-inclusive $J/\psi + jet$ production is a promising process to study gluon transverse momentum distribution (TMDs) at the future electron-ion collider (EIC). A back-to-back configuration allows a higher transverse momentum for $J/\psi$. We present an extension of a previous work where we studied $\cos2\phi$ azimuthal asymmetry within the TMD factorization framework for this process. We present and compare the effect of TMD evolution on the asymmetry, in two approaches that differ in the parameterization of the perturbative tails of the TMDs and the non-perturbative factors. We show that the asymmetry depends on the parameterizations of the non-perturbative Sudakov factors in the larger $b_T$ region and on the perturbative part of the evolution kernel. We use NRQCD to estimate the $J/\psi$ production and show the effect of using different long-distance matrix element (LDME) sets. Overall, the asymmetry after incorporating TMD evolution is small, but increases with the transverse momentum imbalance of the $J/\psi$-jet pair.

hep-ph↗
arXiv2024

Angular momentum distribution for a quark dressed with a gluon: different decompositions

We present a recent calculation of the quark and gluon contributions to the angular momentum of a composite spin -$1/2$ state in QCD. The state we consider is a quark dressed with a gluon, and we use the two-component framework in light-front Hamiltonian QCD. We compare the results from different decompositions available in the literature. We also present the angular momentum distributions.

hep-ph↗
arXiv2024

Unraveling Gluon TMDs in $J/\psi$ and Pion production at the EIC

We investigate the azimuthal asymmetries such as $\cos2{\phi_T}$ and Sivers symmetry for $J/\psi$ and $\pi^\pm$ production in electron-proton scattering, focusing on scenarios where the $J/\psi$ and the pion are produced in an almost back-to-back configuration. The electron is unpolarized, while the proton can be unpolarized or transversely polarized. For the $J/\psi$ formation, we use non-relativistic QCD (NRQCD), while $\pi^\pm$ is formed due to parton fragmentation. In this kinematics, we utilize the transverse momentum-dependent factorization framework to calculate the cross sections and asymmetries. We consider both quark and gluon-initiated processes and show that the gluon contribution dominates. We provide numerical estimates of the upper bounds on the azimuthal asymmetries, as well as employ a Gaussian parametrization for the gluon transverse momentum distributions (TMDs), within the kinematical region accessible by the upcoming Electron-Ion Collider (EIC).

hep-ph↗
arXiv2024

BharatBench: Dataset for data-driven weather forecasting over India

Advanced weather and climate models use numerical techniques on grided meshes to simulate atmospheric and ocean dynamics, which are computationally expensive. Data-driven approaches are gaining popularity in weather and climate modeling, with a broad scope of applications. Although Machine Learning (ML) has been employed in this domain, significant progress has occurred in the past decade, leading to ML applications that are now competitive with traditional numerical methods. This study presents a user-friendly dataset for data-driven medium-range weather forecasting focused on India. The dataset is derived from IMDAA reanalysis datasets and optimized for ML applications. The study provides clear evaluation metrics and a few baseline scores from simple linear regression techniques and deep learning models. The dataset can be found at https://www.kaggle.com/datasets/maslab/bharatbench, while the codes are available at https://github.com/MASLABnitrkl/BharatBench. We hope this dataset will boost data-driven weather forecasting over India. We also address limitations in the current evaluation process and future challenges in data-driven weather forecasting.

physics.ao-ph↗
arXiv2024

Gravitational Form Factors and Mechanical Properties of Quarks in Protons: A Basis Light-Front Quantization Approach

We compute the gravitational form factors (GFFs) and study their applications for the description of the mechanical properties such as the pressure, shear force distributions, and the mechanical radius of the proton from its light-front wave functions (LFWFs) based on basis light-front quantization (BLFQ). The LFWFs of the proton are given by the lowest eigenvector of a light-front effective Hamiltonian that incorporates a three-dimensional confining potential and a one-gluon exchange interaction with fixed coupling between the constituent quarks solved in the valence Fock sector. We find acceptable agreement between our BLFQ computations and the lattice QCD for the GFFs. Our $D$-term form factor also agrees well with the extracted data from the deeply virtual Compton scattering experiments at Jefferson Lab, and the results of different phenomenological models. The distributions of pressures and shear forces are similar to those from different models.

hep-ph↗
arXiv2024

Gluon generalized parton distributions of the proton at non-zero skewness

Using a recently developed light-front spectator model that incorporates gluon, where the light-front wave functions are modeled from the soft-wall AdS/QCD prediction, we examine the leading twist gluon generalized parton distributions (GPDs) inside the proton. We derive the chirally even and odd distributions by using the overlap representation of the light-front wave functions. In terms of GPDs at non-zero skewness, we investigate the entire three-dimensional representation of gluons. We analyse the gluon impact parameter distributions at $\xi=0$ using the Fourier transform of GPDs. We address the total angular momentum contribution of the gluons by using the Ji's sum rule and also give our predictions for both the canonical and kinetic orbital angular momentum in the light-cone gauge.

hep-ph↗
arXiv2023

Spatial distribution of Angular Momentum Inside a Quark State Dressed with a Gluon

We investigate the different decompositions of the angular momentum in QCD for a relativistic spin $1/2$ composite state, namely a quark dressed with a gluon. We use light-front Hamiltonian perturbation theory, and in the light-front gauge, use the two-component framework by eliminating the constrained degrees of freedom. We also investigate the different decompositions of the angular momentum at the level of two-dimensional densities in the front form, including the effect of the so-called potential term. In this work, we consider the contribution coming from the quark part of the energy-momentum tensor. We contrast the different decompositions and also compare with other calculations in the literature. We also present the gravitational form factor related to the antisymmetric part of the energy-momentum tensor.

hep-ph↗