We determine the strong coupling constant alpha_s from the au; hadronic width using renormalization group summed expansion of the QCD Adlerfunction. The main theoretical uncertainty in the extraction of alpha_s is due tothe way in which renormalization group invariance is implemented and the yetuncalculated higher order terms in the QCD perturbative series. We show that new expansion exhibitsnice renormalization group improvement and the behaviour of the series is similar tostandard CIPT expansion. We further study the convergence properties of this expansion improved byBorel transformation and the analytical continuation in the Borel plane. We find that thenew, non-power expansions for different conformal mappings have remarkable convergence. Finally weprovide the value of strong coupling alpha_s using the new, non-power perturbative expansionswhich is alpha_s(M_ au ) = 0.3189+0.0145−0.0115, which translates to alpha_s(M_Z ) =0.1184+0.0018−0.0015.
17/04/2013 at 4:00 pm
Mr. Suprabh Prakash, IIT, Bombay
HEP Seminar
Lecture Hall Block A, Institute of Physics
Document Date:
Exploring 3-flavor effects with present and next generation long baseline superbeam neutrino experiments
Exploring 3-flavor effects with present and next generation long baseline superbeam neutrino experiments
Abstract
Various neutrino experiments till now, have explored the dominant 2-flavoreffects in neutrino oscillations.They have been very successful in constraining some of the oscillationparameters. The next step in thisfield is building experiments which will probe the sub-dominant 3-flavoreffects and the related oscillationparameters. This is a difficult task. In this talk, I will start with abrief discussion of the physics of neutrinooscillations. This will be followed by a discussion of the present statusof the neutrino oscillation parameters.Finally, I will present my work which is phenomenology of present and nextgeneration long baselinesuperbeam neutrino experiments.
16/04/2013 at 4:00 pm
Prof. Naresh Dadhich, Jamia Milia Islamia University
The Higgs boson is believed to have been discovered at the Large HadronCollider.The task now is to verify whether the boson is indeed the scalar Higgs asproposedin the Standard Model of particle physics, or something more esoteric asproposedin the plethora of extensions to the Standard Model. We present a step bystepmethodology to determine the properties of this resonance without makinganyassumptions about its couplings. We present the analysis in terms ofmeasurementsthat would require the minimum number of events. We show that by studyingthe threeuni-angular distributions and other readily measurable observables, one canunambiguouslyconfirm whether the new boson is indeed the Higgs with J^{PC} = 0^{++} andwith couplingsto Z bosons exactly as predicted in the Standard Model.
