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A. S. Cornell

Publications and source records attributed to A. S. Cornell.

At least 55 records · Page 3Linked to original sources
arXiv2006

Little Higgs model effects in $γγ\to γγ$

Though the predictions of the Standard Model (SM) are in excellent agreement with experiments there are still several theoretical problems associated with the Higgs sector of the SM, where it is widely believed that some ``{\it new physics}'' will take over at the TeV scale. One beyond the SM theory which resolves these problems is the Little Higgs (LH) model. In this work we have investigated the effects of the LH model on $\gggg$ scattering \cite{Choudhury:2006xa}.

hep-ph↗
arXiv2006

Little Higgs model effects at $γγ$ collider

Though the predictions of the Standard Model (SM) are in excellent agreement with experiments there are still several theoretical problems, such as fine-tuning and the hierarchy problem. These problems are associated with the Higgs sector of the SM, where it is widely believed that some {\it ``new physics"} will take over at the TeV scale. One beyond the SM theory which resolves these problems is the Little Higgs (LH) model. In this work we shall investigate the effects of the LH model on $\gggg$ scattering; where the process $\gggg$ at high energies occurs in the SM through diagrams involving $W$, charged quark and lepton loops (and is, therefore, particularly sensitive to any new physics

hep-ph↗
arXiv2006

Graviton emission from a higher-dimensional black hole

We discuss the graviton absorption probability (greybody factor) and the cross-section of a higher-dimensional Schwarzschild black hole (BH). We are motivated by the suggestion that a great many BHs may be produced at the LHC and bearing this fact in mind, for simplicity, we shall investigate the intermediate energy regime for a static Schwarzschild BH. That is, for $(2M)^{1/(n-1)}ω\sim 1$, where $M$ is the mass of the black hole and $ω$ is the energy of the emitted gravitons in $(2+n)$-dimensions. To find easily tractable solutions we work in the limit $l \gg 1$, where $l$ is the angular momentum quantum number of the graviton.

hep-th↗
arXiv2005

CP violation in the $B \to K \ell^+ \ell^-$ decay

Standard Model (SM) CP asymmetries in $B \to K \ell^+ \ell^-$ are expected to be very small. This feature could help in the understanding of new physics scenarios which predict the existence of CP odd phases in various Wilson coefficients. In this paper we have analyzed the $B \to K \ell^+ \ell^-$ decay in beyond the SM scenarios where the Wilson coefficients have new CP odd phases. The sensitivity of the CP asymmetries on these new weak phases is discussed.

hep-ph↗
arXiv2005

FB asymmetries in the $B \to K^* \ell^+ \ell^-$ decay: A model independent approach

Among the various "rare" semi-leptonic decays of $B$-mesons the $B \to K^* \ell^+ \ell^-$ mode is of special interest. This is because it has the highest branching ratio among all the semi-leptonic B decays within the SM. This channel also provides us with a very large number of possible observables, such as the Forward Backward (FB) asymmetry, lepton polarization asymmetry etc. Of special interest is the zero which the FB asymmetry has in this decay mode. In this work we have studied this zero in the most general model independent framework.

hep-ph↗
arXiv2005

Signatures of new Physics in dileptonic B-decays

Leptonic decays of $B$-mesons are theoretically very clean probes for testing the Standard Model (SM) and possible physics beyond it. Amongst the various leptonic decays of the $B$-meson, the pure dileptonic decay $B \to \ell^+ \ell^-$ is very important as this mode is helicity suppressed in the SM but can be substantially enhanced in some of the models beyond the SM, such as supersymmetric (SUSY) theories and the two Higgs doublet model (2HDM). Although the purely dileptonic decay mode is helicity suppressed in the SM its associated mode $B \to \ell^+ \ell^- γ$ does not have the same suppression, due to the presence of the $γ$ in the final state. In this paper we will also analyse the effects of enhanced $Z$-penguins on these two decay modes.

hep-ph↗
arXiv2005

Lepton polarization asymmetries for $B \to K^* \ell^+ \ell^-$: A Model Independent approach

In this work we shall derive expressions for the single and double lepton polarization asymmetries for the exclusive decay $B \to K^* \ell^+ \ell^-$, using the most general model independent effective Hamiltonian. We have conducted this study with this particular channel as it has the highest branching ratio among the various purely leptonic and semi-leptonic decay modes, making this mode particularly useful for studying physics beyond the SM. We have also analyzed the effects on these polarization asymmetries, and hence the physics underlying it, when complex phases are included in some of the Wilson coefficients.

hep-ph↗
arXiv2004

The effects of enhanced Z penguins on lepton polarizations in $B \to X_s \ell^+ \ell^-$

The sensitivity of the $B \to πK$ mode to electroweak penguins and the recent experimental data for the $B \to ππ$, $πK$ modes has given rise to what is known as the ``$B \to πK$ puzzle''. Recently it has been observed that this {\sl puzzle} can be resolved by considering the new physics which can enter via $Z^0$ penguins. In this note we analyze the effect of this enhanced $Z^0$ penguins on the lepton polarization asymmetries of $b \to s \ell^+ \ell^-$.

hep-ph↗
arXiv2004

Supersymmetric effects on Forward Backward asymmetries of $B \to K \ell^+ \ell^-$

Leptonic and semi-leptonic rare decays of B-mesons are very clean (both theoretically and experimentally) signatures of any new physics beyond the Standard Model (SM). More specifically the decay \btokll has been theoretically observed to be very sensitive to new physics as the Forward Backward (FB) asymmetry in this decay mode vanishes in the SM. Supersymmetry, however, predicts a non-vanishing value of this asymmetry. In this work we will study the polarized lepton pair FB asymmetry, i.e. the FB asymmetry of the lepton when one (or both) final state lepton(s) are polarized. We will study these asymmetries both within the SM and for Supersymmetric corrections to the SM.

hep-ph↗
arXiv2003

The Forward Backward asymmetries of $B \to X_s τ^+ τ^-$ in the MSSM

The relatively clean theoretical probes of the Standard Model (SM), and the various theories beyond the SM, provided by radiative, semi-leptonic and (purely) leptonic decays of B-mesons have become increasingly important. Due to the large number of possible distributions in the semi-leptonic decays based on the quark level transition $b \to s \ell^+ \ell^-$ (not just the branching ratio), these transitions have become very useful. A study of the Forward-Backward asymmetries for the inclusive decay ($B \to X_s \ell^+ \ell^-$) is carried out in this paper. This study shall be performed in the SM and a minimal supersymmetric extensions of the SM, namely the mSUGRA model.

hep-ph↗
arXiv2003

Lepton polarization correlations in $B \to K^* τ^- τ^+$

In this work we will study the polarizations of both leptons ($τ$) in the decay channel $B\to K^* τ^- τ^+$. In the case of the dileptonic inclusive decay $B\to K^* \ell^- \ell^+$, where apart from the polarization asymmetries of single lepton $\ell$, one can also observe the polarization asymmetries of both leptons simultaneously. If this sort of measurement is possible then we can have, apart from decay rate, FB asymmetry and the six single lepton polarization asymmetries (three each for $\ell^-$ and $\ell^+$), nine more double polarization asymmetries. This will give us a very useful tool in more strict testing of SM and the physics beyond. We discuss the double polarization asymmetries of $τ$ leptons in the decay mode $B\to K^* τ^- τ^+$ within the SM and the Minimal Supersymmetric extensions of it.

hep-ph↗
arXiv2002

Non-Abelian Monopole and Dyon Solutions in a Modified Einstein-Yang-Mills-Higgs System

We have studied a modified Yang-Mills-Higgs system coupled to Einstein gravity. The modification of the Einstein-Hilbert action involves a direct coupling of the Higgs field to the scalar curvature. In this modified system we are able to write a Bogomol'nyi type condition in curved space and demonstrate that the positive static energy functional is bounded from below. We then investigate non-Abelian sperically symmetric static solutions in a similar fashion to the `t Hooft-Polyakov monopole. After reviewing previously studied monopole solutions of this type, we extend the formalism to included electric charge and we present dyon solutions.

hep-th↗
arXiv2002

Weak Scale Quantum Gravity Effects for $γγ\to ZZ$ in the TeV region

We consider the effect of massive spin-2 gravitons that occur as Kaluza-Klein excitations of the graviton in a Weak scale Quantum Gravity scenario on the process $γγ\to ZZ$, which in the Standard Model can proceed through loop diagrams. For a wide range of parameters, we show that the massive gravitons leave behind signatures that should be verifiable in a TeV scale scattering experiment.

hep-ph↗
arXiv2001

TeV-scale electron Compton scattering in the Randall-Sundrum scenario

The spin-2 graviton excitations in the Randall-Sundrum gravity model provides a t-channel contribution to electron Compton scattering which competes favourably with the standard QED contributions. The phenomenological implications of these contributions to the unpolarized and polarized cross-sections are evaluated.

hep-ph↗
arXiv2000

Radion signature in $γγ$ scattering

We investigate the phenomenological consequences of the possible existence of the radion at a TeV-scale for $γγ$ scattering in the TeV range. We find that polarized cross-sections only give possible experimental signatures for the radion.

hep-ph↗