arXiv subjects

M. Sajjad Athar

Publications and source records attributed to M. Sajjad Athar.

At least 109 records · Page 6Linked to original sources

arXiv2012

$ν(\barν)$-$^{208}$Pb deep inelastic scattering

Nuclear-medium effects in the weak structure functions $F_2(x,Q^2)$ and $F_3(x,Q^2)$ in the charged current neutrino and antineutrino induced deep inelastic reactions in $^{208}$Pb have been studied. The calculations have been performed in a theoretical model using relativistic nuclear spectral functions which incorporate Fermi motion, binding and nucleon correlations. We also consider the pion and rho meson cloud contributions calculated from a microscopic model for meson-nucleus self-energies. Using these structure functions, the results for the differential cross section have been obtained and compared with the CERN Hybrid Oscillation Research apparatUS (CHORUS) data. The results for the ratios $\frac{2F_{i}^{Pb}}{208F_i^D}$, $\frac{4F_{i}^{Pb}}{208F_i^{He}}$, $\frac{12F_{i}^{Pb}}{208F_i^C}$, $\frac{16F_{i}^{Pb}}{208F_i^O}$, and $\frac{56F_{i}^{Pb}}{208F_i^{Fe}}$ (i=2,3) have also been obtained and a few have been compared with some of the phenomenological fits.

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arXiv2011

Antineutrino induced antikaon production off the nucleon

The charged current antikaon production off nucleons induced by antineutrinos is studied at low and intermediate energies. We extend here our previous calculation on kaon production induced by neutrinos. We have developed a microscopic model that starts from the SU(3) chiral Lagrangians and includes background terms and the resonant mechanisms associated to the lowest lying resonance in the channel, namely, the Sigma*(1385). Our results could be of interest for the background estimation of various neutrino oscillation experiments like MiniBooNE and SuperK. They can also be helpful for the planned antineutrino experiments like MINERvA, NOvA and T2K phase II and for beta-beam experiments with antineutrino energies around 1 GeV.

hep-ph↗

arXiv2011

Nuclear medium effects in $ν(\barν)$-nucleus deep inelastic scattering

We study the nuclear medium effects in the weak structure functions $F_2(x,Q^2)$ and $F_3(x,Q^2)$ in the deep inelastic neutrino/antineutrino reactions in nuclei. We use a theoretical model for the nuclear spectral functions which incorporates the conventional nuclear effects, such as Fermi motion, binding and nucleon correlations. We also consider the pion and rho meson cloud contributions calculated from a microscopic model for meson-nucleus self-energies. The calculations have been performed using relativistic nuclear spectral functions which include nucleon correlations. Our results are compared with the experimental data of NuTeV and CDHSW.

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arXiv2011

Strange particle production at low and intermediate energies

The weak kaon production off the nucleon induced by neutrinos and antineutrinos is studied at low and intermediate energies of interest for some ongoing and future neutrino oscillation experiments. We develop a microscopical model based on the SU(3) chiral Lagrangians. The studied mechanisms are the main source of kaon production for neutrino energies up to 2 GeV for the various channels and the cross sections are large enough to be amenable to be measured by experiments such as Minerva, T2K and NO$ν$A.

hep-ph↗

arXiv2011

Nuclear medium effects in $ν/\barν$-A DIS

Nuclear medium effects in the weak structure functions $F_2(x,Q^2)$ and $F_3(x,Q^2)$ have been studied for deep inelastic neutrino/antineutrino reactions in iron nucleus by taking into account Fermi motion, binding, pion and rho meson cloud contributions, target mass correction, shadowing and anti-shadowing corrections. The calculations have been performed in a local density approximation using relativistic nuclear spectral functions which include nucleon correlations. Using these structure functions we have obtained the ratio $R_{F2,F3}^A(x,Q^2)= \frac{2F_{2,3}^A(x,Q^2)}{AF_{2,3}^D(x,Q^2)}$, the differential scattering cross section $\frac{1}{E}\frac{d^2σ}{dxdy}$ and the total scattering cross section $σ$. The results of our numerical calculations in $^{56}Fe$ are compared with the experimental results of NuTeV and CDHSW collaborations.

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arXiv2011

Neutral Current $ν$ Induced Reactions in Nuclei at Supernova Neutrino Energies

We calculate cross sections for the neutral current induced neutrino/antineutrino reaction from $^{208}Pb$ target and applied it to study Supernova neutrino event rates. The calculations are done in local density approximation taking into account Pauli blocking, Fermi motion effects and renormalization of weak transition strengths in the nuclear medium. The numerical results for the neutrino nucleus total cross sections have been averaged over the various Supernova neutrino/antineutrino fluxes available in literature.

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arXiv2011

Nuclear medium modification of the F2 structure function

We study the nuclear effects in the electromagnetic structure function F2(x,Q^2) in nuclei in the deep inelastic lepton nucleus scattering process by taking into account Fermi motion, binding, pion and rho meson cloud contributions. Calculations have been done in a local density approximation using relativistic nuclear spectral functions which include nucleon correlations for nuclear matter. The ratios over deuteron structure function are obtained and compared with the recent JLAB results for light nuclei with special attention to the slope of the x distributions. This magnitude shows a non trivial A dependence and it is insensitive to possible normalization uncertainties. The results have also been compared with some of the older experiments using intermediate mass nuclei.

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arXiv2010

Weak Kaon Production off the Nucleon

The weak kaon production off the nucleon induced by neutrinos is studied at the low and intermediate energies of interest for some ongoing and future neutrino oscillation experiments. This process is also potentially important for the analysis of proton decay experiments. We develop a microscopical model based on the SU(3) chiral Lagrangians. The basic parameters of the model are fpi, the pion decay constant, Cabibbo's angle, the proton and neutron magnetic moments and the axial vector coupling constants for the baryons octet, D and F, that are obtained from the analysis of the semileptonic decays of neutron and hyperons. The studied mechanisms are the main source of kaon production for neutrino energies up to 1.2 to 1.5 GeV for the various channels and the cross sections are large enough to be amenable to be measured by experiments such as Minerva and T2K.

hep-ph↗

arXiv2009

CC1$π^+$ to CCQE cross sections ratio at accelerator energies

MiniBooNE and K2K collaborations have recently reported the ratio for the $ν_μ$ induced charge current 1$π^+$ production cross section to the charged current induced quasielastic lepton production cross section i.e. $R(E)=\frac{σ^{CC1π^+}}{σ^{CCQE}}$. In this paper we study, theoretically, in a local density approximation the effect of nuclear medium in charged current quasielastic(CCQE) and charged current one pion production(CC1$π^+$) processes for the $ν_μ$ induced reaction in nuclei. The theoretical results have been compared with the results of experimental observations by the MiniBooNE and K2K collaborations. The ratio R(E) for $ν_μ$ induced reaction in water for the proposed T2K experiment is also presented.

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arXiv2009

A study of nuclear effect in $F_3$ structure function in the deep inelastic $ν(\barν)$ reactions in nuclei

We study nuclear effect in the $F^A_3(x)$ structure function in the deep inelastic neutrino reactions on iron by taking into account Fermi motion, binding, target mass correction, shadowing and anti-shadowing corrections. Calculations have been done in a local density approximation using relativistic nuclear spectral functions which include nucleon correlations for nuclear matter. Results for $F^A_3(x)$ have been compared with the results reported at NuTeV and also with some of the older experiments reported in the literature.

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arXiv2009

Theoretical study of lepton events in the atmospheric neutrino experiments at SuperK

Super-Kamiokande has reported the results for the lepton events in the atmospheric neutrino experiment. These results have been presented for a 22.5kT water fiducial mass on an exposure of 1489 days, and the events are divided into sub-GeV, multi-GeV and PC events. We present a study of nuclear medium effects in the sub-GeV energy region of atmospheric neutrino events for the quasielastic scattering, incoherent and coherent pion production processes, as they give the most dominant contribution to the lepton events in this energy region. We have used the atmospheric neutrino flux given by Honda et al. These calculations have been done in the local density approximation. We take into account the effect of Pauli blocking, Fermi motion, Coulomb effect, renormalization of weak transition strengths in the nuclear medium in the case of the quasielastic reactions. The inelastic reactions leading to production of leptons along with pions is calculated in a $Δ$- dominance model by taking into account the renormalization of $Δ$ properties in the nuclear medium and the final state interaction effects of the outgoing pions with the residual nucleus. We present the results for the lepton events obtained in our model with and without nuclear medium effects, and compare them with the Monte Carlo predictions used in the simulation and the experimentally observed events reported by the Super-Kamiokande collaboration.

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arXiv2008

Quasielastic and inelastic neutrino reactions in $^{12}C$ at K2K energies

In this paper, we present the results of a study made for the effect of nuclear medium in the charged current induced quasielastic lepton production(CCQE) and the incoherent and coherent one pion production (CC1$π^+$)processes from $^{12}C$ in the $ν_μ$ energy region of 0.4-3GeV. The theoretical results are compared with the recent experimental results for the ratio of charged current $ν_μ$ induced one pion production cross section to the quasielastic lepton production cross section reported by K2K collaboration. We also present the results for the angular and momentum distributions of leptons and pions produced in these processes.

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arXiv2008

Nuclear effects in F_3 structure function of nucleon

We study nuclear effects in the $F^A_3(x)$ structure function in the deep inelastic neutrino reactions on iron by using a relativistic framework to describe the nucleon spectral functions in the nucleus. The results for the ratio $R(x,Q^2)=\frac{F^A_3(x,Q^2)}{AF^N_3(x, Q^2)}$ and the Gross-Llewellyn Smith(GLS) integral $G(x,Q^2)=\int_x^1 dx F^A_3(x,Q^2)$ in nuclei are discussed and compared with the recent results available in literature from theoretical and phenomenological analyses of experimental data.

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arXiv2008

Neutrino nucleus cross sections

We present the results of our calculation which has been performed to study the nuclear effects in the quasielastic, inelastic and deep inelastic scattering of neutrinos(antineutrinos) from nuclear targets. These calculations are done in the local density approximation. We take into account the effect of Pauli blocking, Fermi motion, Coulomb effect, renormalization of weak transition strengths in the nuclear medium in the case of the quasielastic reaction. The inelastic reaction leading to production of pions is calculated in a $Δ$- dominance model taking into account the renormalization of $Δ$ properties in the nuclear medium and the final state interaction effects of the outgoing pions with the residual nucleus. We discuss the nuclear effects in the $F_{3}^{A}(x)$ structure function in the deep inelastic neutrino(antineutrino) reaction using a relativistic framework to describe the nucleon spectral function in the nucleus.

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arXiv2008

Neutral Current induced $π^0$ production and neutrino magnetic moment

We have studied the total cross section, $Q^2$, momentum and angular distributions for pions in the $ν$($\bar ν$) induced $π^0$ production from nucleons. The calculations have been done for the weak production induced by the neutral current in the standard model and the electromagnetic production induced by neutrino magnetic moment. It has been found that with the present experimental limits on the muon neutrino magnetic moment $μ_{ν_μ}$, the electromagnetic contribution to the cross section for the $π^0$ production is small. The neutrino induced neutral current production of $π^{0}$, while giving an alternative method to study the magnetic moment of neutrino $μ_{ν_μ}$, does not provide any improvement over the present experimental limit on $μ_{ν_μ}$ from the observation of this process in future experiments at T2K and NO$ν$A.

hep-ph↗

arXiv2007

Nuclear effects in Neutrino Nuclear Cross-sections

Nuclear effects in the quasielastic and inelastic scattering of neutrinos(antineutrinos) from nuclear targets have been studied. The calculations are done in the local density approximation which take into account the effect of nucleon motion as well as renormalisation of weak transition strengths in the nuclear medium. The inelastic reaction leading to production of pions is calculated in a $Δ$ dominance model taking into account the renormalization of $Δ$ properties in the nuclear medium.

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arXiv2007

Single Pion production from Nuclei

We have studied charged current one pion production induced by $ν_μ(\barν_μ)$ from some nuclei. The calculations have been done for the incoherent pion production processes from these nuclear targets in the $Δ$ dominance model and take into account the effect of Pauli blocking, Fermi motion and renormalization of $Δ$ properties in the nuclear medium. The effect of final state interactions of pions has also been taken into account. The numerical results have been compared with the recent results from the MiniBooNE experiment for the charged current 1$π$ production, and also with some of the older experiments in Freon and Freon-Propane from CERN.

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arXiv2007

Charged current anti-neutrino reactions from $^{12}$C at MiniBooNE energies

A study of charged current induced anti-neutrino interactions from nuclei has been done for the intermediate energy ($<2$GeV) anti-neutrinos and applied to $^{12}$C, relevant for ongoing experiment by MiniBooNE collaboration. The calculations have been done for the quasielastic and inelastic lepton production as well as for the incoherent and the coherent pion production processes. The calculations are done in local density approximation. In the case of the quasielastic reaction the effects of Pauli blocking, Fermi motion effects, renormalization of weak transition strengths in nuclear medium and the Coulomb distortion of the outgoing lepton have been taken into account. For the inelastic processes the calculations have been done in the $Δ$ dominance model and take into account the effect of Pauli blocking, Fermi motion of the nucleon and renormalization of $Δ$ properties in a nuclear medium. The effect of final state interactions of pions is also taken into account. The numerical results for the total cross sections for the charged current quasielastic scattering and incoherent pion production processes are compared with earlier experimental results available in Freon and Freon-Propane. It is found that nuclear medium effects give strong reduction in the cross sections leading to satisfactory agreement with the available data.

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