arXiv subjects

Abhijit Samanta

Publications and source records attributed to Abhijit Samanta.

21 records · Page 2Linked to original sources

arXiv2001

Electroweak Precision Data, Light Sleptons and Stability of the SUSY Scalar Potential

The light slepton-sneutrino scenario with non-universal scalar masses at the GUT scale is preferred by the electroweak precision data. Though a universal soft breaking mass at or below the Plank scale can produce the required non-universality at the GUT scale through running, such models are in conflict with the stability of the electroweak symmetry breaking vacuum. If the supergravity motivated idea of a common scalar mass at some high scale along with light sleptons is supported by future experiments that may indicate that we are living in a false vacuum. In contrast SO(10) D-terms, which may arise if this GUT group breaks down directly to the Standard Model, can lead to this spectrum with many striking phenomenological predictions, without jeopardizing vacuum stability.

hep-ph↗

arXiv2001

New Bounds on Slepton and Wino Masses in Anomaly Mediated Supersymmetry Breaking Models

We show how the spectrum of the minimal anomaly-mediated supersymmetry breaking model can be constrained from the condition that the electroweak symmetry breaking minimum of the scalar potential is the deepest point in the field space. Applying the current experimental bounds and scanning over the whole parameter space, we rule out selectrons below 378 GeV and staus below 269 GeV, the numbers having a modest uncertainty. We also find a new upper bound on the wino-like chargino mass for a given slepton mass. This rules out the possibility of slepton pair production at ongoing or upcoming colliders like the Tevatron or the Next Linear Collider at $\sqrt{s}=500$ GeV, where pair production of charginos may be the only available signal.

hep-ph↗

arXiv2000

Yukawa Unification and Unstable Minima of the Supersymmetric Scalar Potential

Motivated by the possibilities of $b-τ$ or $t-b-τ$ Yukawa unification in the supersymmetric Grand Unified Theories, we consider the dangerous directions of the supersymmetric potential for large values of $\tanβ(\geq 30)$, in two versions of the minimal supergravity model with and without common soft breaking scalar masses at the GUT scale, where the potential may become unbounded from below. We find that for the common trilinear coupling $A_0 \leq 0$ the requirement of $b-τ$ unification in conjunction with the stability condition on the potential yields highly restrictive sparticle spectra with upper, and in many cases, lower bounds stronger than the available experimental lower bounds, on the soft SUSY breaking common scalar mass and the common gaugino mass. Over a significant region of the parameter space, the model becomes even more restrictive if the common sfermion soft mass is different from the soft mass for the Higgs sector. We also find that the bulk of this restricted parameter space can be probed at the LHC. Im models with $t-b-τ$ Yukawa unification, $A_0 \leq 0$ is ruled out from potential constraints.

hep-ph↗