Sumit K. Garg

MSGUT : From bloom to doom

Abstract By a systematic survey of the parameter space we confirm our surmise [C.S. Aulakh, MSGUTs from germ to bloom: Towards falsifiability and beyond, hep-ph/0506291] that the Minimal Supersymmetric GUT (MSGUT) based on the 210 ⊕ 126 ⊕ 126 ¯ ⊕ 10 Higgs system is incompatible with the generic Type I and Type II seesaw mechanisms. The incompatibility of the Type II seesaw mechanism with this MSGUT is due to its generic extreme sub-dominance with respect to the Type I contribution. The Type I mechanism although dominant over Type II is itself unable to provide neutrino masses larger than ∼ 10 −3 eV anywhere in the parameter space. Our Renormalization Group based analysis shows the origin of these difficulties to lie in a conflict between baryon stability and neutrino oscillation. The MSGUT completed with a 120-plet Higgs is the natural next to minimal candidate. We propose a scenario where the 120-plet collaborates with the 10-plet to fit the charged fermion masses. The freed 120-plet couplings can then give sub-dominant contributions to charged fermion masses and enhance the Type I seesaw masses sufficiently to provide a viable seesaw mechanism. We give formulae required to verify this scenario.

The New Minimal Supersymmetric GUT : Spectra, RG analysis and Fermion Fits

The supersymmetric SO(10) GUT based on the 210⊕10⊕120⊕126⊕126¯ Higgs system provides a minimal framework for the emergence of the R-parity exact MSSM at low energies and a viable supersymmetric seesaw explanation for the observed neutrino masses and mixing angles. We present formulae for MSSM decomposition of the superpotential invariants, tree level light charged fermion effective Yukawa couplings, Weinberg neutrino mass generation operator, and the d=5, ΔB=ΔL≠0 effective superpotential in terms of GUT parameters. We use them to determine fits of the 18 available fermion mass-mixing data in terms of the superpotential parameters of the NMSGUT and SUGRY (NUHM) type soft supersymmetry breaking parameters ({mf˜,m1/2,A0,MH,H¯2}) specified at the MSSM one-loop unification scale MX0=1016.33GeV. Our fits are compatible with electroweak symmetry breaking and Unification constraints and yield right-handed neutrino masses in the leptogenesis relevant range: 108–1013GeV. Matching the SM data requires lowering the strange and down quark Yukawas in the MSSM via large tanβ driven threshold corrections and characteristic soft Susy breaking spectra. The standard model Higgs mass emerges less than 130 GeV. The Susy spectra have light pure Bino LSP, heavy exotic Higgs(inos) and large μ, A0, MH,H¯ parameters ∼100 TeV. Typically third generation sfermions are much heavier than the first two generations. The smuon is often the lightest charged sfermion thus offering a Bino–CDM co-annihilation channel. The parameter sets obtained are used to calculate B violation rates which are found to be generically much faster (∼10−28yr−1) than the current experimental limits. Improvements which may allow acceptable B violation rates are identified.

Anomalous triple gauge boson couplings in e−e+→γγ for noncommutative standard model

Abstract We investigate e + e − → γ γ process within the Seiberg–Witten expanded noncommutative standard model (NCSM) scenario in the presence of anomalous triple gauge boson couplings. This study is done with and without initial beam polarization and we restrict ourselves to leading order effects of noncommutativity i.e. O ( Θ ) . The noncommutative (NC) corrections are sensitive to the electric component ( Θ → E ) of NC parameter. We include the effects of Earthʼs rotation in our analysis. This study is done by investigating the effects of noncommutativity on different time averaged cross section observables. We have also defined forward backward asymmetries which will be exclusively sensitive to anomalous couplings. We have looked into the sensitivity of these couplings at future experiments at the International Linear Collider (ILC). This analysis is done under realistic ILC conditions with the center of mass energy (c.m.) s = 800 GeV and integrated luminosity L = 500 fb − 1 . The scale of noncommutativity is assumed to be Λ = 1 TeV . The limits on anomalous couplings of the order 10 − 1 from forward backward asymmetries while much stringent limits of the order 10 − 2 from total cross section are obtained if no signal beyond SM is seen.

Anomalous triple gauge boson couplings in

Abstract We investigate e + e − → γ γ process within the Seiberg–Witten expanded noncommutative standard model (NCSM) scenario in the presence of anomalous triple gauge boson couplings. This study is done with and without initial beam polarization and we restrict ourselves to leading order effects of noncommutativity i.e. O ( Θ ) . The noncommutative (NC) corrections are sensitive to the electric component ( Θ → E ) of NC parameter. We include the effects of Earthʼs rotation in our analysis. This study is done by investigating the effects of noncommutativity on different time averaged cross section observables. We have also defined forward backward asymmetries which will be exclusively sensitive to anomalous couplings. We have looked into the sensitivity of these couplings at future experiments at the International Linear Collider (ILC). This analysis is done under realistic ILC conditions with the center of mass energy (c.m.) s = 800 GeV and integrated luminosity L = 500 fb − 1 . The scale of noncommutativity is assumed to be Λ = 1 TeV . The limits on anomalous couplings of the order 10 − 1 from forward backward asymmetries while much stringent limits of the order 10 − 2 from total cross section are obtained if no signal beyond SM is seen.

e^{-}e^{+} \to \gamma \gamma

We show that superheavy threshold corrections in the New Minimal Supersymmetric GUT based on the SO(10) Higgs system can comfortably correct the prediction for the value of α3(MZ) from the relatively large value predicted by the two-loop RG equations to the central value determined by the current world average. The unification scale is raised above the one-loop value over almost all of the viable parameter space.

for noncommutative standard model

We analyze e+e− → γγ, e−γ → e−γ and γγ → e+e− processes within the Seiberg-Witten expanded noncommutative scenario using polarized beams. With unpolarized beams the leading order effects of non commutativity starts from second order in non commutative (NC) parameter i.e. O(Θ2), while with polarized beams these corrections appear at first order (O(Θ)) in cross section. The corrections in Compton case can probe the magnetic component

CORRECTING α3(MZ) in the NMSGUT

\left( {{{\overrightarrow \Theta }_B}} \right)

TeV scale implications of non commutative space time in laboratory frame with polarized beams

while in Pair production and Pair annihilation probe the electric component

Top Yukawa coupling measurement with indefinite CP Higgs in e(+)e(-) -> t(t)over-bar Phi

\left( {{{\overrightarrow \Theta }_E}} \right)

Probing the indefinite CP nature of the Higgs boson through decay distributions in the process e(+)e(-) -> t(t)over-bar Phi

of NC parameter. We include the effects of earth rotation in our analysis. This study is done by investigating the effects of non commutativity on different time averaged cross section observables. The results which also depends on the position of the collider, can provide clear and distinct signatures of the model testable at the International Linear Collider (ILC).