High Energy Physics Seminars
Search for a light Higgs boson in the radiative decays of Y(1S)
by Dr. Vindhyawasini Prasad ((IIT Guwahati, Assam))
Tuesday, October 9, 2012
from
to
(Asia/Kolkata)
at Colaba Campus ( AG 66 )
at Colaba Campus ( AG 66 )
TIFR
Description |
The Higgs boson is essential to explain the origin of mass of elementary particles within the Standard Model (SM) via Higgs mechanism through spontaneous breaking of the electroweak symmetry. The Large Hadron Collider (LHC) experiment at CERN has recently found an evidence for a Higgs-like state with a mass of ≈ 126 GeV/c2. However, a light Higgs boson is also predicted by many extensions of the SM including the Next-to-Minimal Supersymmetric Standard Model (NMSSM). The Higgs sector of the NMSSM contains a total of three CP-even, two CP-odd and two charged Higgs bosons. The lightest CP-odd Higgs boson (A0) could have a mass smaller than twice the mass of b-quark, making it detectable via radiative Y(nS)→γA0 (n=1,2,3) decays. These Υ(nS) resonances have narrow width and are produced below the BBbar threshold, providing a clean environment for new physics searches. We search for di-muon decays of a light Higgs boson in the fully reconstructed decay chain of Y(2S,3S) → π+π- Y(1S), Y(1S)→γA0, A0→μ+μ- using the datasets of (92.8 ± 0.8) million Υ(2S) and (116.8 ± 1.0) million Υ(3S) events collected by BaBar experiment at SLAC, USA. The Y(1S) sample is selected by tagging the pion pair in the Y(2S,3S) → π+π-Y(1S) transitions. We find no evidence for A0 production in the Y(2S) and Y(3S) datasets and set 90% C.L. upper limits on the product branching fraction B(Y(1S)→γA0)×B(A0→μ+μ-) as well as effective Yukawa coupling of b-quark to the A0. |