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A. Fatima

Publications and source records attributed to A. Fatima.

18 recordsLinked to original sources
arXiv2026

Weak charged current induced electron and positron scattering off proton at JLab and MAMI energies

The development of next-generation, high-luminosity, and high-precision charged lepton beam facilities at JLab and MAMI has opened, in recent years, a new frontier in the exploration of weak interaction processes induced by electrons and positrons in the neutral current sector, which can also be used to study weak interaction processes induced by charged currents. In particular, these processes in the intermediate energy regime, spanning from a few hundred MeV to a few GeV, play a crucial role in understanding electroweak dynamics, nucleon structure, and hadronic response functions. This review presents a comprehensive theoretical study of weak charged-current interactions of electrons and positrons with free protons, encompassing quasielastic scattering in both the strangeness conserving and strangeness changing channels, together with inelastic production of the $P_{33}$(1232), $P_{11}$(1440), $S_{11}$(1535) resonances, $\eta$ and $K$ mesons, and associated production of strange particles. We analyse differential and total cross sections, polarization observables of the final baryons, and spin asymmetries of the proton target, demonstrating their sensitivity to the underlying weak interaction dynamics and to possible second class currents, thereby enabling stringent tests of G- and T- invariance. The explored kinematic region also offers a unique and independent opportunity to constrain the axial vector sector of the weak interaction, and it provides a discussion of alternative ways to determine the axial dipole mass in the quasielastic scattering region, a fundamental parameter that is in debate for nearly two decades. It also focuses on the study of the axial-vector form factors associated with the excitation of the $P_{33}(1232)$ resonance in a manner that is free from the uncertainties inherent in their determination from studies of (anti)neutrino-induced weak processes.

hep-ph↗
arXiv2026

Charged current induced electron-proton scattering and the axial vector form factor

We investigate the total scattering cross section($\sigma$), the differential cross section$\left(\frac{d\sigma}{dQ^2}\right)$, the longitudinal($A_L(E_e,Q^2)$) and perpendicular($A_P(E_e,Q^2)$) spin asymmetries of the polarized target proton, as well as the longitudinal($P_L(E_e,Q^2)$), perpendicular($P_P(E_e,Q^2)$), and transverse($P_T(E_e,Q^2)$) polarization components of the final neutron, in the weak charged current induced electron-proton scattering relevant to the future experiments at the Thomas Jefferson National Accelerator Facility(JLab) and Mainz Microtron(MAMI). The analysis is performed assuming time-reversal(T) invariance as well as without assuming T invariance, allowing for a nonvanishing transverse polarization component of the final nucleon, perpendicular to the production plane. Numerical results are presented for the above mentioned observables, and their sensitivities to the various parameterizations of the axial vector form factor $g_1(Q^2)$ and a nonzero weak electric form factor $g_2(Q^2)$ are examined. We find that the cross section depends strongly on the parameterizations used for the axial vector form factor. Moreover, the dipole parameterization of $g_1(Q^2)$ with a higher value of the axial dipole mass $M_A$ simulates the apparent enhancement in $\sigma$ obtained using the non-dipole parameterizations like the $z$-expansion and Faddeev equation form. The cross sections are found to depend only weakly on the weak electric form factor $g_2(Q^2)$, which is associated with the violation of G-invariance. On the contrary, the spin observables both $A_{L,P}(E_e, Q^2)$ and $P_{L,P}(E_e, Q^2)$ are found to be strongly dependent on $g_2(Q^2)$. This study may be useful in the analysis of the neutrino oscillation experiments to provide an alternative constrain on the parameterization of axial vector form factor, which currently has large uncertainties.

hep-ph↗
arXiv2025

Charged current neutrino and antineutrino induced associated particle production from nucleons

In this work, we study the charged-current (anti)neutrino-induced associated particle($K\Lambda$) production($\Delta S=0$) from free nucleons in the energy region of a few GeV, relevant to the (anti)neutrino oscillation experiments with accelerator and atmospheric neutrinos. We employ a model based on effective Lagrangians to evaluate the contributions from the nonresonant and the resonant diagrams. The nonresonant background terms are calculated using a microscopic model derived from the SU(3) chiral Lagrangians. For the resonant contributions, we consider the low-lying spin-$\frac{1}{2}$ resonances, such as $S_{11}(1650)$, $P_{11}(1710)$, $P_{11}(1880)$, and $S_{11}(1895)$, and spin-$\frac{3}{2}$ resonances, such as $P_{13}(1720)$ and $P_{13}(1900)$, which have finite branching ratios to the $K\Lambda$ channel. These resonant contributions are modelled using an effective phenomenological Lagrangian approach, with strong couplings determined from the experimental branching ratios and the decay widths to the $K\Lambda$ channel. To fix the parameters of the vector current interaction, the model is first used to reproduce satisfactorily the MAMI experimental data on the real photon induced scattering off the nucleon resulting an eta meson in the final state and with the CLAS data for the $K\Lambda$ production in the final state. The PCAC hypothesis and the generalized Goldberger-Treiman relation are used to fix the parameters of the axial vector interaction. The model is then applied to study the weak production of $K\Lambda$ induced by the neutrinos and antineutrinos, and predicts the numerical values for the $Q^2$-distribution, the kaon kinetic energy distribution, and the total scattering cross sections with and without a cut on the CM energy W. The results presented in this work are relevant for the present and future accelerator and atmospheric neutrino experiments.

hep-ph↗
arXiv2024

Charged current neutrino scattering from nucleons

In this work, we study the charged current induced neutrino and antineutrino scattering from the free nucleon target. This study has been performed in the energy range of a few GeV, relevant for the (anti)neutrino oscillation experiments with accelerator and atmospheric neutrinos. For a few GeV neutrino, the contribution to the cross section mainly comes from the quasielastic, the inelastic production of mesons like pion, kaon, eta, and hyperons as well as from the deep inelastic scattering by the weak currents in $\Delta S$=0 and $\Delta S$=1 sectors. The numerical results are presented for the $Q^2$ distribution of the differential cross section for all the aforementioned processes. The effect of the cut on the center of mass energy $W$ has been explicitly discussed.

hep-ph↗
arXiv2024

Charged current weak production of $\Delta(1232)$ induced by electrons and positrons

The charged current weak production of $\Delta (1232)$ from the free proton target induced by the electron/positron in the intermediate energy range corresponding to the beam energy available at JLab and Mainz, has been studied. The results for the differential scattering cross section $\frac{d\sigma}{dQ^2}$, the angular distribution $\frac{d\sigma}{d\Omega_{\Delta}}$, and the total scattering cross section $\sigma(E_e)$ for both the electron and positron induced processes are presented, for the various energies in the range of 0.5--4~GeV. The cross section $\sigma(E_e)$ is found to be of the order of $10^{-39}$~cm$^{2}$ for the electron/positron energies in the few GeV range. The availability of electron/positron beams having well defined energy and direction with very high luminosity of the order of $10^{38}-10^{39}$~cm$^{-2}$~sec$^{-1}$, makes it possible to observe the weak charged current production of $\Delta(1232)$ and determine the axial vector form factors $C_{i}^{A} (Q^2);~(i=3-5)$. The sensitivity of the differential cross section $\frac{d\sigma}{dQ^2}$ to the subdominant form factors $C_{3}^{A}(Q^2)$ and $C_{4}^{A} (Q^2)$ is found to be strong enough, especially in the low $Q^2$ region, which can be used to determine them phenomenologically and to test the various theoretical models proposed to calculate them.

hep-ph↗
arXiv2023

Weak production of $\eta$ mesons induced by $\nu_{\mu}(\bar{\nu}_\mu)$ at MicroBooNE energies

We have studied neutral and charged current (anti)neutrino induced $\eta$ production off the free nucleon target at MicroBooNE energies, in the light of recent results reported by the MicroBooNE collaboration for the total $\eta$ production cross section. This study has been made using a theoretical model in which the weak hadronic current receives contribution from the nonresonant Born terms as well as from the resonance excitations. The Born terms are obtained using the SU(3) symmetric chiral model, used earlier in the study of $K-$meson production. The contribution from the resonance terms is considered from the excitation of five nucleon resonances viz. $S_{11}(1535)$, $S_{11}(1650)$, $P_{11}(1710)$, $P_{11}(1880)$, and $S_{11}(1895)$. To fix the parameters of the vector current interaction, this model is first used to study the electromagnetic production of $\eta$ mesons induced by real and virtual photons, and the theoretical results have been compared with the data from the MAINZ and JLab experiments. The partially conserved axial-vector current hypothesis and generalized Goldberger-Treiman relation are used to fix the parameters of the axial-vector current interaction. The results are presented for the total cross section for the neutral and charged current induced $\eta$ production, ratio of the cross sections for the charged current to neutral current, MicroBooNE flux averaged cross section $\langle \sigma \rangle$, $\left \langle \frac{d\sigma}{dQ^2} \right\rangle$ and $\left\langle \frac{d\sigma}{dp_\eta} \right\rangle$, which may be useful in the future analysis of MicroBooNE as well as other accelerator and atmospheric neutrino experiments being performed in the ${\cal O}$(1)~GeV energy region.

hep-ph↗
arXiv2022

Charged current (anti)neutrino induced eta production off the nucleon

The charged current (anti)neutrino induced eta production from the nucleons is studied in a model based on the effective Lagrangians to evaluate the contribution from the nonresonant and resonant diagrams. The contribution from the nonresonant background terms has been obtained using a microscopic model based on the SU(3) chiral Lagrangians. The contribution from the resonant diagrams due to the low lying $S_{11}(1535)$, $S_{11} (1650)$, and $P_{11} (1710)$ resonances has been evaluated using an effective phenomenological Lagrangian with its parameters determined from the experimental values of their branching ratios and decay widths to the $N\eta$ channel. The model is first used to reproduce satisfactorily the experimental data from the MAINZ and JLab on the total cross sections for the photo- and electro- production of $\eta$ mesons, which fixes the model parameters in the vector current interaction. The PCAC hypothesis and generalized Goldberger-Treiman relation are used to fix the parameters of the axial vector interaction. The model is then applied to study the weak production of eta mesons induced by the neutrinos and antineutrinos, and predicts the numerical values for the $Q^2$-distribution, $\eta$-momentum distribution, and the total cross section for the reactions $\nu_{\mu} + n \longrightarrow \mu^{-} + p + \eta$ and $\bar{\nu}_{\mu} + p \longrightarrow \mu^+ + n + \eta$ in the energy region up to 2 GeV. It is found that the photo, electro, and (anti)neutrino production of eta mesons is dominated by the contribution from the $S_{11}(1535)$ resonance. The results discussed in this work are relevant for the present and future accelerator experiments like MicroBooNE, T2K, NOvA, MINERvA, T2-HyperK and DUNE as well as for the atmospheric neutrino experiments.

hep-ph↗
arXiv2022

Neutrinos and their interactions with matter

We have presented a review of the properties of neutrinos and their interactions with matter. The different (anti)neutrino processes like the quasielastic scattering, inelastic production of mesons and hyperons, and the deep inelastic scattering from the free nucleons are discussed and the results for the scattering cross sections are presented. The polarization observables for the leptons and hadrons produced in the final state, in the case of quasielastic scattering, are also studied. The importance of nuclear medium effects in the low, intermediate and high energy regions, in the above processes along with the processes of the coherent neutrino-nucleus scattering, coherent meson production, and trident production, have been highlighted. In some cases the results of the cross sections are also given and compared with the available experimental data as well as with the predictions in the different theoretical models. This study would be helpful in understanding the (anti)neutrino interaction cross section with matter in the few GeV energy region relevant to the next generation experiments like DUNE, Hyper-Kamiokande, and other experiments with accelerator and atmospheric neutrinos. We have emphasized the need of better theoretical models for some of these processes for studying the nuclear medium effects in nuclei.

hep-ph↗
arXiv2022

Hyperon production in quasielastic $\bar{\nu}_{\tau}-$nucleon scattering

The theoretical results for the total cross sections and polarization components of the $\tau^{+}$ lepton produced in the charged current induced $|\Delta S| = 1$ quasielastic $\bar\nu_\tau - N$ scattering leading to hyperons ($\Lambda, \Sigma$) have been presented assuming T invariance. The theoretical uncertainties arising due to the use of different vector, axial vector and pseudoscalar form factors as well as the effect of SU(3) symmetry breaking have been studied. We have also presented, for the first time, a comparison of the total cross sections for the production of $e,\mu,\tau$ leptons to facilitate the implications of lepton flavor universality~(LFU) in the $|\Delta S| = 1$ quasielastic reactions induced by the antineutrinos of all flavors i.e., $\nu_{l};~l=e,\mu,\tau$.

hep-ph↗
arXiv2021

T-violating effect in $\nu_{\tau} (\bar{\nu}_{\tau})-$nucleon quasielastic scattering

The production cross sections and polarization observables of the $\tau$ leptons produced in the $|\Delta S| = 0$ and $1$ induced $\nu_{\tau}(\bar{\nu}_{\tau})-N$ quasielastic scattering have been studied. The effect of T violation, in the case of $\Delta S=0$ and 1 processes, and the SU(3) symmetry breaking effects, in the case of $\Delta S=1$ processes, on the total scattering cross sections as well polarization observables are explored. Experimentally, it would be possible to observe these effects in the forthcoming (anti)neutrino experiments like DUNE, SHiP and DsTau.

hep-ph↗
arXiv2021

$\bar{\nu}_{\mu}$ induced quasielastic production of hyperons leading to pions

The quasielastic production cross sections and polarizations of the hyperons induced by ${\bar\nu}_\mu$ on the free nucleon as well as from $^{40}$Ar in the sub-GeV energy region has been reviewed [1-5]. The effects of the second class currents in the axial vector sector with and without T-invariance as well as the effect of SU(3) symmetry breaking are also studied. We find that the cross sections and the various polarization components can effectively be used to determine the axial vector transition form factors in the strangeness sector and to test the validity of various symmetries of the weak hadronic currents like G-invariance, T-invariance and SU(3) symmetry. These hyperons decay dominantly into pions giving an additional contribution to the weak pion production induced by the antineutrinos. In the case of nuclear targets like $^{40}$Ar, this contribution is shown to be significant when compared with the pion production by the $\Delta$ excitations in the energy range of $E_{\bar{\nu}_{\mu}} \le 0.7$ GeV [1]. This study could be useful for the DUNE experiment where argon will be used as the target material and the electronic imaging of particles is possible and the particle tracks can be identified.

hep-ph↗
arXiv2021

Super-Resolution Time-Resolved Imaging using Computational Sensor Fusion

Imaging across both the full transverse spatial and temporal dimensions of a scene with high precision in all three coordinates is key to applications ranging from LIDAR to fluorescence lifetime imaging. However, compromises that sacrifice, for example, spatial resolution at the expense of temporal resolution are often required, in particular when the full 3-dimensional data cube is required in short acquisition times. We introduce a sensor fusion approach that combines data having low-spatial resolution but high temporal precision gathered with a single-photon-avalanche-diode (SPAD) array with set of data that has high spatial but no temporal resolution, such as that acquired with a standard CMOS camera. Our method, based on blurring the image on the SPAD array and computational sensor fusion, reconstructs time-resolved images at significantly higher spatial resolution than the SPAD input, upsampling numerical data by a factor 12x12, and demonstrating up to 4x4 upsampling of experimental data. We demonstrate the technique for both LIDAR applications and FLIM of fluorescent cancer cells. This technique paves the way to high spatial resolution SPAD imaging or, equivalently, FLIM imaging with conventional microscopes at frame rates accelerated by more than an order of magnitude.

eess.IV↗
arXiv2020

Quasielastic production of polarized $\tau$ leptons in $\nu_{\tau}$ and $\bar{\nu}_{\tau}$ scattering from nucleons

The cross sections and polarization components of the $\tau$ leptons produced in the charged current induced quasielastic $\nu_\tau~(\bar\nu_\tau) - N$ scattering have been studied. The theoretical uncertainties arising due to the use of different vector form factors and the axial dipole mass in the axial vector form factor have been investigated. Due to the high mass of $\tau$ lepton, the contributions from the term containing pseudoscalar and second class current form factors are non-negligible and contribute to the uncertainty in the cross section and polarization observables as these form factors are not well known. In view of the currently proposed experiments by DUNE, SHiP and DsTau collaborations to study the production of $\tau$ lepton, an updated calculation of the cross sections and polarizations of tau leptons in the case of quasielastic production have been done and the numerical results have been presented along with a discussion of the theoretical uncertainties.

hep-ph↗
arXiv2020

Photon induced K$\Lambda$ production on the proton in the low energy region

The associated photoproduction of $K\Lambda$ from the proton in the low energy region is studied using an isobar model in which the non-resonant contributions are obtained from the non-linear sigma model with chiral SU(3) symmetry which predicts, in a natural way, the contact term with its coupling strength along with the coupling strengths of the various Born terms predicted by the non-linear sigma model. The present model is an extension of the non-linear sigma model with chiral SU(2) symmetry, used earlier to study the photo, electro, and neutrino productions of pions. In the resonance sector, the contributions from the well established nucleon resonances ($R$) in the $s$ channel, the hyperon resonances ($Y^{*}$) in the $u$ channel, and the kaon resonances ($K^{*}$ and $K_{1}$) in the $t$ channel having spin $\le \frac{3}{2}$ and mass $<2$ GeV with a significant branching ratio in $K\Lambda$ decay mode, have been considered. The strong and electromagnetic couplings of the $s$ channel nucleon resonances are taken from experiments while the couplings for the resonances in the $t$ and $u$ channels are fitted to reproduce the current data on the associated photoproduction of $K\Lambda$ in this energy region. The numerical results are presented for the total and differential cross sections and are compared with the available experimental data from CLAS and SAPHIR as well as with some of the recent theoretical models.

hep-ph↗
arXiv2018

Weak quasielastic hyperon production leading to pions in the antineutrino-nucleus reactions

In this review, we have studied the quasielastic production cross sections and polarization components of $\Lambda$, $\Sigma^0$ and $\Sigma^-$ hyperons induced by the weak charged currents in the antineutrino reactions on the nucleon and the nuclear targets like $^{12}$C, $^{16}$O, $^{40}$Ar and $^{208}$Pb. It is shown that the energy and the $Q^2$ dependence of the cross sections and the various polarization components can be effectively used to determine the axial vector transition form factors in the strangeness sector and test the validity of various symmetry properties of the weak hadronic currents like G-invariance, T-invariance and SU(3) symmetry. In particular, the energy and the $Q^2$ dependence of the polarization components of the hyperons is found to be sensitive enough to determine the presence of the second class current with or without T-invariance. These hyperons decay dominantly into pions giving an additional contribution to the weak pion production induced by the antineutrinos. This contribution is shown to be quantitatively significant as compared to the pion production by the $\Delta$ excitation in the nuclear targets in the sub-GeV energy region relevant for the $\bar{\nu}_\mu$ cross section measurements in the oscillation experiments. We have also included a few new results, based on our earlier works, which are in the kinematic region of the present and future (anti)neutrino experiments being done with the accelerator (anti)neutrinos at T2K, MicroBooNE, MiniBooNE, NO$\nu$A, MINER$\nu$A and DUNE, as well as for the atmospheric (anti)neutrino experiments in this energy region.

hep-ph↗
arXiv2018

Second class currents and T violation in quasielastic neutrino and antineutrino scattering from nucleons

The effect of the second class currents with and without time reversal invariance has been studied in the quasielastic production of nucleons and hyperons induced by neutrinos and antineutrinos from the nucleons. The numerical results are presented for the total scattering cross section~($\sigma$) as well as for the longitudinal, perpendicular and transverse components of the polarization of the final baryons ($p$, $n$, $\Lambda$, $\Sigma^-$, $\Sigma^0$) and muon produced in the quasielastic (anti)neutrino-nucleon scattering induced by the weak charged current. In the case of the production of $\Lambda$ hyperon, which is the most suitable candidate for making the polarization measurements, we have also calculated the $Q^2$ dependence of the polarization observables and the differential scattering cross section ($d\sigma/dQ^2$). The measurement of the polarization observables and their $Q^2$ dependence provides an independent way to determine the nucleon-hyperon transition form factors at high $Q^2$ which can provide tests of the symmetries of the weak hadronic currents like G-invariance, T invariance and SU(3) symmetry.

hep-ph↗
arXiv2018

Polarization observables and T-noninvariance in the weak charged current induced electron proton scattering

In this work, we have studied the total scattering cross section ($\sigma$), differential scattering cross section ($d\sigma/dQ^2$) as well as the longitudinal ($P_L(E_e,Q^2)$), perpendicular ($P_P(E_e,Q^2)$), and transverse ($P_T(E_e,Q^2)$) components of the polarization of the final hadron ($n$, $ \Lambda$ and $\Sigma^0$) produced in the electron proton scattering induced by the weak charged current. We have not assumed T-invariance which allows the transverse component of the hadron polarization perpendicular to the production plane to be non-zero. The numerical results are presented for all the above observables and their dependence on the axial vector form factor and the weak electric form factor are discussed. The present study enables the determination of the axial vector nucleon-hyperon transition form factors at high $ Q^2$ in the strangeness sector which can provide test of the symmetries of the weak hadronic currents like T-invariance and SU(3) symmetry while assuming the hypothesis of conserved vector current and partial conservation of axial vector current.

hep-ph↗
arXiv2017

Weak quasielastic electroproduction of hyperons with polarization observables

With the availability of high luminosity electron beam at the accelerators, there is now the possibility of studying weak quasielastic hyperon production off the proton, i.e. $e^-p \to \nu_e Y(Y=\Lambda,\Sigma^0)$, which will enable the determination of the nucleon-hyperon vector and axial-vector transition form factors at high $ Q^2$ in the strangeness sector and provide test of the Cabibbo model, G-invariance, CVC, PCAC hypotheses and SU(3) symmetry. In this work, we have studied the total cross section, differential cross section as well as the longitudinal and perpendicular components of polarization of the final hyperons ($ \Lambda$ and $\Sigma^0$ produced in these reactions) and presented numerical results for these observables and their sensitivity to the transition form factors.

hep-ph↗