arXiv subjects

F. Zolfagharpour

Publications and source records attributed to F. Zolfagharpour.

6 recordsLinked to original sources

arXiv2016

Pionic contribution in the Drell-Yan dilepton production cross section in p-Cu collision in the framework of the shell and Fermi gas models

To investigate the high mass dilepton production cross section produced due to the Drell-Yan process in hadronic collisions such as nucleon- nucleus, the valence and sea quarks distribution functions inside nucleus is used. In this study, in the framework of the shell and Fermi gas models, by adding quarks distribution functions of pions inside nucleus besides the quarks distribution functions of bound nucleons, the changes in the dilepton production cross section were investigated. For this reason, pionic contribution in the structure function of 63Cunucleus and its EMC ratio was first studied using the aforementioned models. Then, in the framework of the Drell-Yan process using GRV's nucleons and pions quarks distribution functions, the high mass dilepton production cross section in p-cu collision was calculated and compared with the available experimental data. The extracted results, based on the two mentioned models, were greatly the same and by considering the pionic contribution, the theoretical results were consistent with the experimental data.

nucl-th↗

arXiv2016

Investigation of pionic contribution in the lepton and anti-lepton production cross section in p-Cu and p-Pt collision

For detailed explanation of the experimental results of lepton production cross section in hadronic collisions such as nucleon-nucleon or nucleon-nuclei, it is of great importance to use quarks and sea quarks distribution function inside free and bound nucleons. In this paper the role of pion cloud inside the nucleus in the structure function of Cu and Pt nuclei and the EMC ratio of these nuclei were investigated by using harmonic oscillator model.

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arXiv2014

Form factors and decay rate of $B_c^\ast \rightarrow D_{s}~l^+ l^-$ decays in the QCD sum rules

Rare exclusive $B_c^\ast \rightarrow D_{s}~l^+ l^-$ decays are analyzed in the framework of the three--point QCD sum rules approach. The two gluon condensate corrections to the correlation function are included and the form factors of this transition are evaluated. Using the form factors, the decay width and integrated decay rate for these decays are also calculated.

hep-ph↗

arXiv2008

EMC effect with different oscillator-model parameters $hω$ for different shells by considering difference between proton and neutron structure functions

The magnitude of binding energy used in the conventional nuclear theory to explain the EMC experimental data, seems to be larger than the one expected. In this paper to get sufficient depletion in the binding energy, different oscillator-model parameters $ \textit{$hω$} $ for different shells and the proton (neutron) structure function that have good agrement with experimental data are used. The extracted results for $^4He, ^{12}C, ^{40}Ca$ and $^{56}Fe$ nuclei show that one can get improved results in medium x ranges by less binding energy.

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arXiv2007

Double Lepton Polarization in $Λ_b -->Λl^+ l^-$ Decay in the Standard Model with Fourth Generations Scenario

This study investigates the influence of the fourth generation quarks on the double lepton polarizations in Λ_b --> Λ\ell^+ \ell^- decay by taking |V^\ast_{t's}V_{t'b}|= 0.005,0.01,0.02,0.03 with phase \{60^\circ,90^\circ,120^\circ\}. We will try to obtain a constrain on the mass of the 4th generation top like quark t', which is consistent with the $b--> s\ell^+\ell^- rate . With the above mentioned parameters, we will try to show that the double lepton(muon, tau) polarizations are quite sensitive to the existence of fourth generation. It can serve as a good tool to search for new physics effects, precisely, to search for the fourth generation quarks(t', b') via its indirect manifestations in loop diagrams.

hep-ph↗

arXiv2005

The effect of quark exchange in A=3 mirror nuclei and neutron/proton structure functions ratio

By using the quark-exchange formalism, realistic Faddeev wave functions and Fermi motion effect, we investigate deep inelastic electron scattering from A=3 mirror nuclei in the deep-valence region. The initial valence quarks in put are taken from the GRV's next-to-leading order calculations on $F_2^p(x,Q^2)$ which give very good fit to the available data in the $(x,Q^2)$-plane. It is shown that the free neutron to proton structure functions ratio can be extracted from corresponding EMC ratios for $^3He$ and $^3H$ mirror nuclei by using self-consistent iteration procedure and the results are in good agreement with other theoretical models as well as present available experimental data, especially the one expected form the proposed 11 GeV Jefferson Laboratory.

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