Particle and Nuclear Physics Seminar at J-PARC

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DATE: 2015 July. 7th 15:00-16:00

PLACE:Tokai 1st Buiding Room115

TITLE:
New results of 13 measurement via the Hydrogenchannel using full data with the Double Chooz Far detector



LANGUAGE: English

SPEAKER: Prof. Ralitsa Sharankova
(Tokyo University of Technology)

CONTACT: Prof. Shunzo Kumano,
j-parc-pn-seminar-(AT)-ml.post.kek.jp




Abstract:

Double Chooz is a reactor neutrino experiment aimed
at precise measurement of the neutriro mixing angle 13.
Inverse beta decays from antineutrino interactions are
observed as coincidences of a prompt signal (positron)
and a delayed signal (neutron capture). The main analysis
channel uses neutron captures on Gadolinium. However
a supplementary channel exists that uses captures on
Hydrogen.
In this talk we report new results of the Double Chooz
13 measurement via the Hydrogen capture channel
using the full Far detector-only dataset. In this analysis
backgrounds are greatly suppressed due to innovative
background rejection techniques. These include a
neural-network- based multivariate analysis and pulse
shape discrimination that takes advantage of the full
channel readout by Flash-ADCs. The neutrino spectrum
distortion that was observed in the Gd analysis is
checked using the independent H capture sample.
Combining the H and Gd samples results in more
than a factor two increase in statistics.This could be
used to enhance the sensitivity of our Near+Far detector
analysis, especially in the early phase.