Searcharxiv⌕ Search

arXiv subjects

A. A. Billur

Publications and source records attributed to A. A. Billur.

28 records · Page 2Linked to original sources
arXiv2016

Anomalous $WWγ$ couplings with beam polarization at the Compact Linear Collider

We study the anomalous $WWγ$ couplings at the Compact Linear Collider through the processes $e^{+}e^{-}\to W^+W^-$, $e^{-}e^{+} \to e^{-} γ^{*} e^{+} \to e^{+} ν_{e} W^-$ and $e^{-}e^{+}\to e^{-} γ^{*} γ^{*} e^{+} \to e^{-} W^+ W^- e^{+} $ $ (γ^{*}$ is the Weizsacker-Williams photon). We give the 95\% confidence level limits for unpolarized and polarized electron (positron) beam on the anomalous couplings for various values of the integrated luminosities and center-of-mass energies. We show that the obtained limits on the anomalous couplings through these processes can highly improve the current experimental limits. In addition, our limits with beam polarization are approximately two times better than the unpolarized case.

hep-ph↗
arXiv2015

Improved bounds on the dipole moments of the tau-neutrino at high-energy $γ^* e^-$ and $γ^* γ^*$ collisions: ILC and CLIC

In this work we study the potential of the processes $e^+e^- \to e^+γ^* e^- \to e^+τ\barν_τν_e $ and $e^+e^- \to e^+γ^* γ^* e^- \to e^+ν_τ\barν_τe^- $ at a future high-energy and high-luminosity linear electron positron collider, such as the ILC and CLIC to study the sensibility on the anomalous magnetic and electric dipole moments of the tau-neutrino. For integrated luminosity of 590\hspace{1mm}$fb^{-1}$ and center-of-mass energy of 3\hspace{1mm}$TeV$, we derive $95 \% \hspace{1mm}C. L.$ limits on the dipole moments: $μ_{ν_τ}\leq 1.44 \times 10^{-6}μ_B$ and $d_{ν_τ}\leq 2.78 \times 10^{-17}\hspace{1mm} e\hspace{0.5mm} cm$ in the $γ^* e^-$ collision mode and of $μ_{ν_τ}\leq 3.4 \times 10^{-7}μ_B$ and $d_{ν_τ}\leq 6.56 \times 10^{-18}\hspace{1mm} e\hspace{0.5mm}cm$ with the $γ^*γ^*$ collision mode, improving the existing limits.

hep-ph↗
arXiv2015

Graviton production through photon-quark scattering at the LHC

We have investigated real graviton emission in the ADD and RS model of extra dimensions through the photoproduction process pp-> p gamma p-> pGqX at the LHC. We have considered all contributions from the subprocesses gamma q -> G q, where q=u,d,c,s,b,anti-u,anti-d, anti-c, anti-s, anti-b quark. The constraints on model parameters of the ADD and RS model of extra dimensions have been calculated. During numerical calculations we have taken account of 3, 4, 5 and 6 large extra dimensional scenarios. The constraints on RS model parameters have been calculated by considering G -> gamma gamma, e^- e^+, mu^- mu^+ decay channels of the graviton.

hep-ph↗
arXiv2014

Anomalous interactions of the top quark with photon via flavor changing neutral currents at the CLIC

Photon-photon reaction provides an excellent opportunity to isolate the $tqγ$ vertex. For this purpose, we have examined the potential of the $e^{-}e^{+}\rightarrow e^{-}γ^{*}γ^{*}e^{+}\rightarrow e^{-}t\bar{q}e^{+}\rightarrow e^{-}W b\bar{q}e^{+}$ ($γ^{*}$ is the Weizsacker-Williams photon and $q=u,c$) process to investigate the anomalous $tqγ$ couplings in $γ^{*}γ^{*}$ collisions at the CLIC. We have obtained $95\%$ confidence level limits on the anomalous couplings for various values of the center-of-mass energy and integrated luminosity. We have shown that the limit on anomalous $κ_{tqγ}$ coupling is more restricted with respect to current experimental limits.

hep-ph↗
arXiv2014

Probe of electromagnetic moments of the tau lepton in gamma-gamma collisions at the CLIC

We have investigated the electromagnetic moments of the tau lepton in $e^{+}e^{-} \rightarrow e^{+}γ^{*} γ^{*} e^{-}\rightarrow e^{+}τ\barτe^{-}$ process at the CLIC. We have obtained 95% confidence level bounds on the anomalous magnetic and electric dipole moments for various values of the integrated luminosity and the center of mass energy. We have shown that the $e^{+}e^{-} \rightarrow e^{+}γ^{*} γ^{*} e^{-}\rightarrow e^{+}τ\barτe^{-}$ process at the CLIC leads to a remarkable improvement in the existing experimental bounds on the anomalous magnetic and electric dipole moments.

hep-ph↗
arXiv2013

Probe of extra dimensions in gamma q->gamma q at the LHC

We have examined TeV scale effects of extra spatial dimensions through the processes gamma q-> gamma q where q=u,d,c,s,b, anti-u, anti-d, anti-c, anti-s, anti-b. These processes have been treated in a photon-proton collision via the main reaction pp-> p gamma p-> p gamma qX at the LHC. We have employed equivalent photon approximation for incoming photon beams and performed statistical analysis for various forward detector acceptances.

hep-ph↗
arXiv2012

Anomalous Wtb couplings in gamma-proton collision at the LHC

We study the possibility for the process $pp \rightarrow pγp \rightarrow pW^-t(W^+\bar t)X$ with anomalous Wtb couplings in a model independent effective Lagrangian approach at the LHC. We find 95% confidence level bounds on the anomalous coupling parameters for various values of the integrated luminosity. The improved constraints on the anomalous Wtb couplings have been obtained compared to current limits.

hep-ph↗
arXiv2012

Search for excited electrons through $γγ$ scattering

We study the potential of $γγ$ option of future high energy linear $e^{+}e^{-}$ colliders to search for excited electrons with spin-1/2. We calculate single production cross sections, give the angular distributions and $f-m^*$ contour plots for $\sqrt{s}=0.5$ TeV and $\sqrt{s}=3$ TeV both using the standard (tree level) couplings and anomal couplings.

hep-ph↗
arXiv2011

Anomalous WWgamma couplings in gamma-proton collision at the LHC

We examine the potential of pp-> p gamma p -> p W q X reaction to probe anomalous WWgamma couplings at the LHC. We find 95% confidence level bounds on the anomalous coupling parameters with various values of the integrated luminosity. We show that the reaction pp -> p gamma p -> p W q X at the LHC highly improve the current limits.

hep-ph↗