arXiv subjects

S. Penaranda

Publications and source records attributed to S. Penaranda.

24 records · Page 2Linked to original sources

arXiv2004

SUSY-electroweak one-loop contributions to Flavour-Changing Higgs-Boson Decays

The SUSY-EW one-loop quantum contributions to flavour-changing MSSM Higgs-boson decays into $b \bar s$ and $s \bar b$ are computed and discussed. We use the full diagrammatic approach that is valid for all $\tan β$ values and do not rely on the mass-insertion approximation for the characteristic flavour-changing parameter. We analyze in full detail the dependence of these flavour-changing partial widths on all the relevant MSSM parameters and also study the non-decoupling behaviour of these widths with the SUSY mass parameters. We find that these contributions are sizable as compared to the SM ones, and together with the SUSY-QCD contributions they can be very efficient as an indirect method in the future search for Supersymmetry.

hep-ph↗

arXiv2003

Higgs decays in the Two Higgs Doublet Model: Large quantum effects in the decoupling regime

We study the Higgs-boson decays h0 -> b \bar{b}, h0 -> γγand h0 -> γZ within the framework of the Two Higgs Doublet Model (THDM) in the context of the decoupling regime, together with tree level unitarity constraints. We show that when the light CP-even Higgs boson of the THDM mimics the Standard-Model Higgs boson, not only the one-loop effects to h0 -> {γγ,γZ} but also the one-loop contribution to h0 -> b \bar{b} can be used to distinguish between THDM and SM. The size of the quantum effects in h0 -> b \bar{b} are of the same order as in h0 -> {γγ,γZ} and can reach 25% in both cases.

hep-ph↗

arXiv2001

Decoupling Properties of MSSM particles in Higgs and Top Decays

We study the supersymmetric (SUSY) QCD radiative corrections, at the one-loop level, to $h^0$, $H^{\pm}$ and t quark decays, in the context of the Minimal Supersymmetric Standard Model (MSSM) and in the decoupling limit. The decoupling behaviour of the various MSSM sectors is analyzed in some special cases, where some or all of the SUSY mass parameters become large as compared to the electroweak scale. We show that in the decoupling limit of both large SUSY mass parameters and large CP-odd Higgs mass, the $Γ(h^0\to b \bar b)$ decay width approaches its Standard Model value at one loop, with the onset of decoupling being delayed for large $\tanβ$ values. However, this decoupling does not occur if just the SUSY mass parameters are taken large. A similar interesting non-decoupling behaviour, also enhanced by $\tanβ$, is found in the SUSY-QCD corrections to the $Γ(H^+\to t \bar b)$ decay width at one loop. In contrast, the SUSY-QCD corrections in the $Γ(t\to W^+ b)$ decay width do decouple and this decoupling is fast.

hep-ph↗

arXiv1999

The SM as the Quantum Low Energy Effective Theory of the MSSM

In the framework of the Minimal Supersymmetric Standard Model we compute the one-loop effective action for the electroweak bosons obtained after integrating out the different sleptons, squarks, neutralinos and charginos, and present the result in terms of the physical sparticle masses. In addition we study the asymptotic behaviour of the two, three and four point Green's functions with external electroweak bosons in the limit where the physical sparticle masses are very large in comparison with the electroweak scale. We find that in this limit all the effects produced by the supersymmetric particles can be, either absorbed in the Standard Model parameters and gauge bosons wave functions, or else they are supressed by inverse powers of the supersymmetric particle masses. This work, therefore, completes the proof of decoupling of the heavy supersymmetric particles from the standard ones in the electroweak bosons effective action and in the sense of the Appelquist-Carazzone Theorem that we started in a previous work. From the point of view of effective field theories this work can be seen as a (partial) proof that the SM can be obtained indeed from the MSSM as the quantum low energy effective theory of this latter when the SUSY spectra is much heavier than the electroweak scale.

hep-ph↗

arXiv1998

Do heavy sfermions decouple from low energy Standard Model?

We explore analytically how does the Standard Model emerge as the quantum low energy effective theory of the Minimal Supersymmetric Standard Model (MSSM) in the decoupling limit where the sparticles are much heavier than the electroweak scale. In this work we integrate the sfermions to one-loop and compute their contributions to the effective action for standard electroweak gauge bosons. A proof of decoupling of sfermions is performed by analyzing the resulting effective action in the asymptotic limit $m_{\tilde f} \gg m_z$. A discussion on how the decoupling takes place in terms of both the sparticle physical masses and the non-physical MSSM parameters is included.

hep-ph↗

arXiv1997

Decoupling of Supersymmetric Particles in the MSSM

A heavy supersymmetric spectrum at the Minimal Supersymmetric Standard Model is considered and the decoupling from the low energy electroweak scale is analyzed. A formal and partial proof of decoupling of supersymmetric particles in the limit where their masses are larger than the electroweak scale is performed by integrating out all the sparticles to one loop and by evaluating the effective action for the standard electroweak gauge bosons $W^{\pm}, Z$ and $γ$. The Higgs sector is not considered here. Analytical results for the two-point functions of the electroweak gauge bosons and the $S, T$ and $U$ parameters, to be valid in that limit, are also presented. A discussion on how the decoupling takes place in terms of both the physical sparticle masses and the non-physical mass parameters as the $μ$-parameter and the soft-breaking parameters is included.

hep-ph↗