S. H. Ahn

Characteristics of hybrid plastic scintillators for slow neutron measurements

In this paper, we report the characteristics and the performance of the hybrid plastic scintillators for slow neutron measurements. The 10B-doped and Gd-layered scintillators were manufactured and tested for slow and fast neutrons, and gamma rays. The slow neutrons were provided by an energy moderation of the fast neutrons emitted from a 0.5 Ci 252Cf source. The energy of the slow neutrons ranged from 10 to 600 meV with a peak at 75 meV. Neutron response functions for the hybrid plastic scintillators were measured with the calibrated slow neutron flux. Furthermore, the pulse-shape analysis was performed to differentiate the slow neutrons from the gamma rays. For the 10B-doped scintillators, the difference lying in the tail-to-total charge ratio distribution of the pulses was conductive to estimate the fraction of the gamma rays in the neutron data. However, for the Gd-layered scintillators, the difference was insignificant.

Search for the Higgs boson in H ---> WW(*) decays in p anti-p collisions at s**(1/2) = 1.96-TeV.

We present a search for the standard model Higgs boson in H --> WW(*) decays with e+e-, e+/-mu-/+, and mu+mu- final states in pp collisions at a center-of-mass energy of square root of s = 1.96 TeV. The data, collected from April 2002 to June 2004 with the D0 detector, correspond to an integrated luminosity of 300-325 pb(-1), depending on the final state. The number of events observed is consistent with the expectation from backgrounds. Limits from the combination of all three channels on the Higgs boson production cross section times branching ratio sigma x BR(H --> WW(*) are presented.