Sterile analysis status and plans stefania bordoni NuPRISM - - PowerPoint PPT Presentation

Sterile analysis status and plans

stefania bordoni

NuPRISM workshop 21-24 April 2016

Stefania Bordoni (CERN / IFAE)

Analysis status (I)

Short reminder of the analysis:

• νe appearance with the 3+1 model
• 4m radius detector
• shape + rate analysis based on both the reconstructed energy and the off-axis
• signal events are calculated by re-weighting the νe background according to the

νe/νµ flux ratio

• Apply the oscillation probability

2

uInt15, Osaka 13

T2K-II statistics

Analysis still based on the expected performances

• f NuPRISM extrapolated from SK

A sample of muon neutrino is also considered but νµ disappearance probability is considered negligible

• Build of a χ2 estimator for correlated Gaussian

distributions with a covariance matrix :

Stefania Bordoni (CERN / IFAE)

Analysis status (II)

• A further step was done to allow for possible muon neutrino disappearance
• Need to develop the analysis in terms of the effective mixing angle
• Marginalisation over |U𝜈4|2 to produce the usual sin22𝜄-Δm2 contours
• John’s results were promising and interesting but needed to be validated with dedicated

studies

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• 𝑉𝜈4

2:

𝑉𝜈4

2

𝑉𝜈4

2

sin2(𝜄𝜈𝑓) 𝑉𝜈4

2 ≈ (0,0.02)

4∣U μ 4∣

2=sin 2(2θμe)/∣U e 4∣ 2

• After John’s departure a part of the code is

no more available and need to be re- implemented

Stefania Bordoni (CERN / IFAE) 4

Next developments

• 1. The new reconstruction and nue-selection has recently become available
• My idea is first start using it out-of the box as was done for the current analysis.
• Possible optimisation of the selection can be studied on a second time as well as the use
• f constraints (nue-background, ND280..)
• I need to better understand how to use the selection and how to apply systematics to be

able to provide a new sensitivity estimation for the June PAC meeting

• Are now MC files produced for all off-axis position?
• Even remotely, I hope to profit of the workshop to progress on how to run the new jobs
• 2. I am working on recovery the developments done by John to consider also the muon

neutrino disappearance and marginalise over it

• Small progresses on the re-implementation but still under development

Stefania Bordoni (CERN / IFAE)

Commitment to the analysis

5

• I have recently changed institution and I am no more (100%) T2K
• Synergies with T2K are very well considered and I am encouraged to continue work in T2K
• Negotiations on the way to do this are on-going
• My activities in NuPRISM are also supported (NuPRISM possibly related to T2K-II or DUNE? )

In practice:

• it is still difficult to estimate the time I will be able to commit on the further developments of this

analysis

• I will do my best to apply at least out-of-the-box the new nue-selection based on the reconstruction

and see how the sensitivity

• I am looking forward to find someone to share the work for those developments or to take over to

ensure regular progresses and delivery of new results.

Stefania Bordoni (CERN / IFAE)

Supplementary

6

Stefania Bordoni (CERN / IFAE)

Some numbers

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Bkg intrinsic νe from νµ 5893 5574 νµ to oscillate signal

(sin22ϑ = 0.002, Δm2=3.14 )

661694 676.4 Background events Signal events

1.1 < OAA ≤ 1.8 1.8 < OAA ≤ 2.5 2.5 < OAA ≤ 3.2 3.2 < OAA ≤ 3.9 K+ 427 450 388 346 µ+ 1152 970 677 429 K0 170 128 160 130 π+ 18 23 22 11

Intrinsic νe background composition νµ background composition

1.1 < OAA ≤ 1.8 1.8 < OAA ≤ 2.5 2.5 < OAA ≤ 3.2 3.2 < OAA ≤ 3.9 CCQE 309 180 85 49 CCπ0 74 28 18 7 NCπ0 1407 586 229 145 CCOthers 340 128 31 18 NCOthers 1017 395 181 113