arXiv subjects

I. Sahin

Publications and source records attributed to I. Sahin.

31 records · Page 2Linked to original sources

arXiv2009

Effect of top quark spin on the unparticle couplings in γγ\to t\bar{t}

We investigate the potential of $γγ$ collisions to probe scalar unparticle couplings via top-antitop quark pair production. We find 95% confidence level limits on the unparticle couplings with an integrated luminosity of $500 fb^{-1}$ and $\sqrt{s}=1$ TeV energy. We investigate the effect of top quark spin polarization on the unparticle couplings. It is shown that spin polarization of the top quark leads to a significant improvement in the sensitivity limits.

hep-ph↗

arXiv2008

Charged current reactions in the NuSOnG and a test of neutrino-W couplings

We explore the physics potential of NuSOnG experiment to probe new physics contributions to $Wμν_μ$ couplings in inverse muon decay and charged current deep inelastic scattering processes. We show that NuSOnG provides two order of magnitude improvement in $Wμν_μ$ compared to LEP bound at 95% C.L.. Combining the results presented here with our earlier results, we obtain a significant improvement in the limits on neutrino flavor universality violation in neutrino-W and neutrino-Z couplings.

hep-ph↗

arXiv2008

Tests of flavor universality for neutrino-Z couplings in future neutrino experiments

We investigate the physics potential of NuSOnG experiment to probe new physics contributions to Z-neutrino-neutrino couplings in muon-neutrino electron elastic and neutral-current deep-inelastic scattering processes. We employ an effective Lagrangian approach and do not a priori assume universality of the coupling of neutrinos to Z. We obtain 95% C.L. limits on possible universality violating couplings.

hep-ph↗

arXiv2008

Anomalous quartic WWgammagamma and WWZgamma couplings through WWZ production in gamma gamma colliders

We find 95% confidence level limits on the anomalous coupling parameters $a_0$, $a_c$ and $a_n$ with an integrated luminosity of $500fb^{-1}$ and $\sqrt s =0.5, 1$ and 1.5 TeV energies. We take into account incoming beam polarizations and also the final state polarizations of the gauge bosons in the cross-section calculations to improve the bounds. We show that polarization leads to a significant amount of improvement in the sensitivity limits.

hep-ph↗

arXiv2008

Anomalous Higgs couplings in egamma collision with initial beam and final state polarizations

We investigate the constraints on the anomalous WWH couplings through the process $e^{-}γ\to ν_{e} W^{-} H$. Considering incoming beam polarizations and the longitudinal and transverse polarization states of the final W boson, we find 95% confidence level limits on the anomalous coupling parameters with an integrated luminosity of 500 $fb^{-1}$ and $\sqrt{s}$= 0.5 and 1 TeV energy. We show that initial beam and final state polarizations highly improve the sensitivity limits of the anomalous coupling parameters $b_{W}$ and $β_{W}$.

hep-ph↗

arXiv2008

Unparticle Physics in the Moller Scattering

We investigate the virtual effects of vector unparticles in the Moller scattering. We derive the analytic expression for scattering amplitudes with unpolarized beams. We obtain 95% confidence level limits on the unparticle couplings $λ_{V}$ and $λ_{A}$ with integrated luminosity of $L_{int}=50, 500 fb^{-1}$ and $\sqrt{s}=100, 300$ and 500 GeV energies. We show that limits on $λ_{V}$ are more sensitive than $λ_{A}$.

hep-ph↗

arXiv2008

Polarized Single Top Quark Production in eγCollision and Anomalous Wtb Couplings

We investigate the potential of $eγ$ collisions to probe anomalous $Wtb$ couplings via the polarized single top quark production process $e^{+} γ\to t \bar{b} \bar{ν_{e}}$. We find 95% confidence level limits on the anomalous coupling parameters $F_{2L}$ and $F_{2R}$ with an integrated luminosity of $500 fb^{-1}$ and $\sqrt{s}=0.5, 1$ and 1.5 TeV energies. The effects of top quark spin polarization on the anomalous $Wtb$ couplings are discussed. It is shown that polarization leads to a considerable improvement in the sensitivity limits.

hep-ph↗

arXiv2008

$WZ$ Production at $eγ$ Colliders and Anomalous Quartic $WWZγ$ Coupling

We investigate the constraints on the anomalous quartic $W^{+}W^{-}Zγ$ gauge boson coupling through the process $e^{-}γ\to ν_{e}W^{-}Z$. Considering incoming beam polarizations and the longitudinal and transverse polarization states of the final W and Z boson we find 95% confidence level limits on the anomalous coupling parameter $a_{n}$ with an integrated luminosity of 500 $fb^{-1}$ and $\sqrt{s}$=0.5, 1 TeV energies. We show that initial beam and final state polarizations improve the sensitivity to the anomalous coupling by up to factors of 2 - 3.5 depending on the energy.

hep-ph↗

arXiv2008

Rare decay Z \to ν\barνγγvia tensor unparticle mediation

The decay width of the rare decay Z \to ν\barνγγis strictly constrained from the LEP data. Tensor unparticles provide a tree-level contribution to this rare decay. We have calculated the tensor unparticle contribution to the rare decay Z\to ν\barνγγ. The current experimental limit have been used to constrain unparticle couplings ν\barνZ {U}^{μν} and γγ{U}^{μν}.

hep-ph↗

arXiv2007

Top Quark Spin Polarization in e γCollision

We investigate the degree of spin polarization of single top quarks in the $eγ$ collision via the process $e^{+} γ\to t \bar{b} \bar{ν_{e}}$ with center of mass energies $\sqrt{s}$=0.5, 1 and 1.5 TeV of the parental linear $e^{+}e^{-}$ collider. Dominant spin fractions and spin asymmetries for the various top quark spin bases are investigated. We show that $e^{+}$-beam direction is the favorite top quark spin decomposition axis. It is found to be comparable with the ones in $pp$ and $ep$ collisions.

hep-ph↗

arXiv2007

Anomalous Quartic $WWγγ$ and $ZZγγ$ Couplings in $eγ$ Collision With Initial Beams and Final State Polarizations

The constraints on the anomalous quartic $WWγγ$ and $ZZγγ$ gauge boson couplings are investigated through the processes $eγ\to W^{-}γν_{e}$ and $eγ\to Zγe$. Considering the longitudinal and transverse polarization states of the final W or Z boson and incoming beam polarizations we find 95% confidence level limits on the anomalous coupling parameters $a_{0}$ and $a_{c}$ with an integrated luminosity of 500 $fb^{-1}$ and $\sqrt{s}$=0.5, 1 TeV energies. Assuming the $W^{+}W^{-}γγ$ couplings are independent of the $ZZγγ$ couplings we show that the longitudinal polarization state of the final gauge boson improves the sensitivity to anomalous couplings by a factor of 2-3 depending on energy and coupling. An extra enhancement in sensitivity by a factor of 1.3 comes from a set of initial beam polarizations.

hep-ph↗

arXiv2004

$ZZγ$ and $Zγγ$ couplings at linear $e^{+} e^{-}$ collider energies with the effects of Z polarization and initial state radiation

The constraints on the neutral gauge boson couplings, $ZZγ$ and $Zγγ$, are investigated at linear $e^{+}e^{-}$ collider energies through the $Zγ$ production with longitudinal and transverse polarization states of the final Z boson. Because of high energy of linear electron- positron beams, initial state radiation (ISR) considerably changes the production cross section. We obtain an increase in the cross section by a factor of 2-3 due to ISR for transverse polarization and by a factor of 10-100 for longitudinal polarization states depending on the energy. We find the 95% C.L. limits on the CP conserving form factors $h_{3}^{Z}$, $h_{4}^{Z}$, $h_{3}^γ$ and $h_{4}^γ$ with integrated luminosity 500$fb^{-1}$ and $\sqrt{s}=$0.5, 1, 1.5 TeV energies. It is shown that the longitudinal polarization of the Z boson, together with ISR, can improve sensitivities by factors 2-3.

hep-ph↗

arXiv2003

$ZZγ$ and $Zγγ$ couplings in $γe$ collision with polarized beams

The potential of $γ$e mode of linear $e^{+}e^{-}$ collider to probe $ZZγ$ and $Zγγ$ vertices is investigated through the Z boson production from the procees $γe\to Z e$. Considering the longitudinal and transverse polarization states of the Z boson and incoming polarized beams we find the 95% C.L. limits on the form factors $h_{3}^{Z}$, $h_{4}^{Z}$, $h_{3}^γ$ and $h_{4}^γ$ with integrated luminosity 500$fb^{-1}$ and $\sqrt{s}=$0.5, 1, 1.5 TeV energies. It is shown that the polarization can improve sensitivities by factors 2-3 depending on the energy.

hep-ph↗