arXiv subjects

Siddhesh Padval

Publications and source records attributed to Siddhesh Padval.

4 recordsLinked to original sources

arXiv2025

Exploring the gluon Sivers function in photon + jet production

We study transverse single spin asymmetries (TSSAs) in back-to-back photon plus jet production in the scattering of unpolarized beams of protons off a transversely polarized proton target as probes of Gluon Sivers Function (GSF). We provide estimates within the region where the imbalance $\vec{q}_{\perp} \equiv \vec{p}_{\gamma\perp} + \vec{p}_{J\perp}$ between the transverse momenta of the photon and the jet is much smaller than the average of the transverse momenta $\vec{p}_{\perp} \equiv \lvert \vec{p}_{\gamma\perp} - \vec{p}_{J\perp} \rvert / 2$ i.e. the back-to-back region. The presence of these two scales in the process makes it particularly suitable for applying transverse momentum dependent (TMD) factorization, in contrast to single-scale processes that rely on the generalized parton model approach. We present our preliminary results of the transverse single spin asymmetry for this process at $\sqrt{s} $ = 200 GeV.

hep-ph↗

arXiv2021

Gluon Sivers function and transverse single spin asymmetries in $e + p^\uparrow \rightarrow γ+ X$

We present estimates of transverse single-spin asymmetry in prompt photon production in the scattering of low virtuality photons off a polarized proton target and discuss the possibility of using this as a probe to get information about the gluon Sivers function (GSF). Using a generalized parton model (GPM) framework, we estimate the asymmetries at electron-ion collider energy ($\sqrt{s}$ =140 GeV) taking into account both direct and resolved photon processes and find that the dominant contribution, up to $10\%$, comes from quark Sivers function (QSF) while the contribution from GSF is found to be up to $2\%$. However, upon taking into account the effects of the process-dependent initial and final state interactions through the color-gauge invariant generalized parton model approach we find that the situation is significantly changed, with near zero contributions from the QSFs and up to a $1\%$ level contribution from the \textit{f}-type GSF. Our results indicate that this process may be useful for distinguishing between GPM and color-gauge invariant generalized parton models and can be used as a good probe of \textit{f}-type GSF.

hep-ph↗

arXiv2019

Probing the Gluon Sivers Function through direct photon production at RHIC

We study the production of prompt-photons at RHIC in the context of a generalised parton model framework, with a view to obtain information on the gluon Sivers function (GSF). At RHIC energy ($\sqrt{s}=200$ GeV), the Compton process, $gq\toγq$ contributes significantly to the production of direct-photons at midrapidity and dominates it in the negative (backward) rapdity region. We find that for direct photons, asymmetries of upto 10\% are allowed by a maximal gluon Sivers function. However, the asymmetry obtained using existing fits of the GSF available is literature is negligible. We also estimate the impact that photons produced via fragmentation can have on the signal and find that their inclusion can dilute the asymmetry by between 10-50\% of the direct-photon value. Finally, using the Colour-Gauge Invariant generalised parton model (CGI-GPM) approach, we consider the effects of initial state and final state interactions which can affect the universality of the Sivers functions in different processes. We find that the inclusion of these effects leads to the size of the gluon contributions being roughly halved. However, in the backward region which we are interested in, the sizes of the quark contributions are suppressed even further, leading to increased dominance of the gluon contributions.

hep-ph↗

arXiv2018

Transverse Single Spin Asymmetry in $J/ψ$ Production

We estimate transverse single spin asymmetry (TSSA) in electroproduction of $J/ψ$ for J-Lab and EIC energies. We present estimates of TSSAs in $J/ψ$ production within generalized parton model (GPM) using recent parametrizations of gluon Sivers function (GSF) and compare the results obtained using color singlet model (CSM) with those obtained using color evaporation model (CEM) of quarkonium production.

hep-ph↗